NINE CHAPTERS (XI-XIX) FROM THE BOOK ENTITLED 'DYNAMIC METEOROLOGY'

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CIA-RDP82-00039R000100220017-9
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360
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December 22, 2016
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March 23, 2012
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17
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February 28, 1952
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REPORT
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Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 STAT Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 V. A. BELINSKIY Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 ' na anva3aw,so,...,.. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 CHAPTER XI VARIATIONS IN GEOSTROPHIC WIND1ITH HEIGHT The geostrophic wind equations show that, due to altitude variations in atmospheric density and in the pressure gradient force, the velocity and direction of the geostrophic wind are functions of altitude. This conclusion remains true even when the horizontal component o1' wind velocity is constant. In the follow rig paragraphs the regularities, to whl.ch the variations of ieostrophic wind w_i th height are subject will be stu.da_ecl. Assuming that 1 = 2 ~) sin p , we write the geostrophic wind equation as fol?aows: 1t v1p. . y ' I) Eliminating the density with the aid of the equation of state we obtain: ~ ate, V ~ a/np___ a/np J y 7__J ax T - '~ 2z c2> Differentiating the first two equations (2) by Z , and the last one by J/ and , ., respectively, and eliminating the com- pound derivatives, we find: _/vI 1 ?7f), z: ( ' r:J ? . I y I 7 1" ~z ( 7/ J C Ti' Declassified in Part -Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 precise formulas, which determine the variations of the velocity components of the geostrophic wind with changes in altitude. iL~r 7_ '- ?zJry . . r r Completing thef1ifferenti_ation and reducing by T, we obtain the aZ r aZ Tyr ~K Let us ascertain the condition, under which the geostrophic wind does not change with height, that is, under what condition u_ = v =0 0 z ~ _z as per (1), we obtains It follows from (~) that, in the absence of change in the u=_ i2:7-_)PT: ~1 -tp (fir az az ay )v 2r geostrophic wind with height the following condition must be satis- : ayr. ar ?-,?.P_ar a ~K y'aZ-~a'=' This means that the isobaric surfaces must, at the same time, be ,isothermi.c surfaces, and therefore, also isosteric surfaces, i. Ce the air must be barotropic If this condition does not exist, the velocity of the geostrophic wind will vary with height. Thus, the variation of the geostrophic wind with height is a result of the baro- Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Equations (9) show that the pressure gradient force at a given upper level can also be considered as consisting of two components: (a) a pressure gradient force conditioned upon the pressure distri- bution at the lower level, and (b) a pressure gradient force conditioned upon the temperature distribution in the given atmospheric layer. By analogy with the "thermic" and "baric" winds, we will call the last item the "thermic" component of the pressure gradient force, and will designate it by ( I&TY) the first item =-- the.'tbaric'l component, which we will designate B upper level. . Obviously: is the pressure gradient force at the Supposing first, that in the atmospheric layer, within which the variations of the geostrophtc wind with height are being con- sidered, the horizontal temperature gradient is absent, that as, we wall first contemplate the variation of the ttbarictt wind with altitude, termined by: 7) and (8), the velocity of the "baric" wind is de- Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 from where: that is: This means, that the direction of the 11baric" wind (determined by the angle , which is formed by the wind with the x-axis) does ~ not change with altitude, coinciding all the time with the direction of the geostrophic wind at the lower level, but the only thing that changes is the absolute value of velocity. we obtain: Thus with the reduction of temperature with altitude (O ),. the o the "baric" wind is, diminished (Q c < d } velocity - zn the isothermic layer (=0)it remains unchanged (Q = 0 ) 9 and ~ in the inversion layer ( yO and r> Q , Q >O Thus, we arrive at the hemisphere, Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 VARIATIONS OF TP ERNIO PhD ;JITH ALTITUDE egrees per 100 kilometers Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 I degree per 100 kilometers 2 degrees per 100 kilometers 1L4.6 10.0 7.8 3 degrees per 100 kilometers L3.2 - 21.9 15.0 11.7 ??9 8.7 8.1 7.8 1~.Ls 7,3 5.0 3.9 3.3 2.9 2.7 2.6 2.. 72.2 36.7 2;.0 19.5 16.3 11.5 13.3 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 goo latitudes only. ? 1n the low latitudes, and, in to presence of higher temperature gradients, even in the high latitudes, the value of the "thermic"wind is not to be overlooked, since in this case, its value is o.f the same order of magnitude, as the velocity of the geostrophic ;+ kilometers, can the value of the "thermic" wind be overlooked (in the formula), and this for high As per egpression (9) in Section 1 and expression (2) in this section, the thermal component of the pressure gradient force is determined by equations x L 7" Equations (6) show, that the thermal components of the pressure gradient :rorce Q & is directed along the temperature gradient' its absolute value is in direct ratio to the absolute value of the temperature gradient pheric layer, as depicted below in Table 11.2, and computed from the we obtain the following values for the variation of the ttthermictt corn- ponent of the pressure gradient force within the 1 - kilometer atmos-? _i de reCs per second, T - 273 degrees Centigrade, B. = 287 M2 Sec~2 per 100 kilometers, Qz in kilometers, and assuming that g = 10 meters r Expressing Q&in millibars per 100 kilometers, in degrees Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 wa~~..aw:m..u..~a.+e..w.t.+?F3.1+~Ya~9~-i~~.ie+i ~a.3'd.".+~W~Ya.e..1:._~,..uYG~:.k.,fl.,r..cY).'~3f`.C"a/-,~KY,YA~.._w..?'1,~w.tX* ~' _ i _. .-. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 millibars `7 RIATIONO IN TH1L TFiE t L COMPONENT OF THE 1 degree per 100 kilometers G.46 0.41 0.32 0.23 0.14 0.09- 0.05 2 degrees per 100 kilometers 0.9 0.8 0.6 0.5 0.3 0b2 0.1 3 degrees per 100 kilometers 1.4 1.2 0.9 0.7 C.h 0.3 0.1 5 degrees per 100 kilometers 2.3 2.0 1.6 1.1 0.7 0.5 0.2 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 pressure gradient force is ever more increasing, in conformance With increase in altitude, the thermal component of the with which there is a steeper inclination of the isobaric surface, as determined by equation It follows from (8) that the isobaric surfaces, with reference to the horizon, will always have a considerable smaller angle of inclination, than the corresponding isothermic surfaces. These angles ~rrherePr is the angle of inclination of the isothermic surface, and zT is the temperature differential at the boundaries of the contem- plated atmospheric layer. Section 3. Variation in Geostrophic ~Ji nd with Height in. Relation to the a~utual ~ispos~:tian of the ire; sure Gradient Force and the dermal In the presence of the ressure gradient force and the thermal gradient, the variations of the geostrophic wind with height may be diverse, with relation to the mutual ciisposition of the above gradients/, or in other ?ords, with relation to the mutual disposition of the iso- bars and isotherms. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 v.euor t;C, i. e, the geostropha..c wind below an' a pointed ou, above, the velocity vector. y ctor of the geostrophic wind at an altitude, can be considered as a product of two vectors: . , vec for J c , 1. the nthermic'wind, wh_~eh is predicated on the mean - therma]. gradient * 'in the conteznlaced atmos)he ~ rjc layer vector C0 is determa.ned in magnitude and direction bY the pressure gradient force vector (j 9 and vector c~ is ci.etermined in magnitude and direction by the the y rural gradient vector / , it being known that vec for Finally vector C is determined by the pressure gradient force Thus, the presure gradient force vector ( can be com:; 1 u ted gradient forced accordance with (7) of Section 2 which s ~" ecla,als which is mul t~.pl i ed by --? times , nd the therri~al component of the pressure a as the vector slum of the pressure gradient force P Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 The greater the thickness of the contemplated atmospheric layer, the less the effect of the first items in equations (1) and and the more the effect of the second items. In confornian c e with this, the cL.rect?on of vector C, with altitude, approximates more and more the direction C , and the di.rec Lion of vector apZ , roxzla to s the direction of vector f . Thus, t~rith increLse in altitude, the direction of the geostrophic wind apYroxirnates the. direction of the isotherm, and the direction of the pressure gradient force approximates the direction of the thermal gradient. Figures 98 and 99 are a diagranurlatic presentation of the variation, with altitude, of the velocity of the geostro hic b p ~.nd and the pressure gradient force. 'they show clearly that the altitud.inal changes in the velocities of the wind tiLll vary, with relation to the disposition of the pressure gradient force and the temperature gradient. Figure 98. The geostrophic wind, with higher altitudes more and more approximates the isotherm altitude. Figure 99'. Variations in the pressure gradi..ent force, with Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Above, we discussed the altitudinal variation of the ttthermict' wind vector4c This variation determines the altitudinal change r in the geostrophic wind. For practical purposes, the wind is con- with relation to the angle O between the pressure and the thermal gradients. . variations in the modulus of velocity and the direction of the wind, the angle determining the direction of the air current, tii!e will derive the corresponding formulas, which express the altitudl.nal scalar magnitudes, the velocity raodulus of the motion of the air and sidered in meteorology not as a vector, but as an aggregate of the two vector sum ~a 1,LIC.1.. , Let us designate the angle formed by velocity c with the x - axis (the isobar at the lower level) as It is obvious that the angle 4lwr r with the isobare The wind velocity c will be the dire Let us the x - axis along the isobar, and the y - axis along the pressure gradient force at the lower level (Figure 100). The ''thermic" wind L~C will be directed along the isotherm, forn~ng Figure 100. Attitudinal var:i..ation in .the velocity and direction of the geostrophic wind, with relation to the angle between the pressure and temperature gradients Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Differentiating equation (6), we derive:. Q u- = 4 c was B effect of to pressure component of the gradient, 7L:: ZL therefore, whe,ice ,Q c szBtc cos ELI B. Since we are disregarding the change in the ti_nd under the L Dr C cos 6 - c2.c/rt L:1e = = 4 c caS O) T (9) , after solving (9) for and L 6 . C .: 0 c:os (G( or, taking into consideration (3) 1_ .._,_ .._ tr cosi' -, 40 4 ,QT c Equations (ii) show that the altitudinal change in the geostrophic wand depends substantially upon the angle (O ), formed between the i.sotherins and the isobars. then (QC - ) is C. when the isobars coincide with tine isotherms, then uz there as no rotation of the wind with higher altitude. z 0 and also in the case when (d) = 180 degrees. If (d- ~ ) = ? 90 degrees,. L1 c w - 0, i, e. the wand changes direction only, without a change in Liz . the magnitude of its velocity, it being the case, that when (OC`-~ )30, Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 0, Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 there is left-hand rotation of the wind,. and when (' 6) 0 there is right-hand rotation. Generally, the smaller the angle (d? ) the more rapid the change in the magnitude of the wind velocity, and the slower the change in its direction. h~hen the thickness of the contemplated atmospheric layer is not too great, the angle (- ) can be considered as the angle that j-s formed by the thermal gradient with the p~ e;sure gradient force at the lower level. hen the thickness of the contemplated atmospheric layer is considerable, the angle 0 ) is an angle that is formed by the pressure gradient force with the thermal gradient at the center level of the atmospheric layer. y y the same token, the magnitude of C, in this case, is to be its magnitude at the center level of the contemplated atmospheric layer. Table L3 characterizes the altitudinal variations in the velocity modulus of the geostrophic wind for various values of the angle (-e ) ~ee page 20 for Table ) 7 The variations in the direction of the wind within a l kilometer atmospheric layer, for various values of (-e) and C are given in Table L2.I. ee page 21 for Table L7 The computations were made on the assumption that - O - 60 degrees, T = 273 degrees Centigrade, = degrees per 100 kilometers, by the formula 4 __ (-6) 83 ? / , A Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 and r . The Table is c om~.uted. for T = 273 degrees Centigrade; Cf 60 degrees; ~. = 1 kilometer, by she forrriula -- Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 TABLE 143 G~+~ziA?7onV ac v~~ocirr 4opv~.u5 o~ GEcasrRMic W'rvD 10 20 34 L.0 50 60 70 80 90 1 degree per 100 kilometers 2.9 2.9 2.7 2.5 2.2 1.9 1.1~. 1.0 0.5 0.0 2 degrees per 100 kilometers 5.8 5.7 5.L. 5?Q 4.1~ 3.7 2.9 2.0 1.0 0.0 N O 3 degrees per 100 kilometers 8.7 8.6 8.1 7.5 6.6 5.6 1t,3 3.0 1.5 0.0 degrees per 100 kilometers 1~.5 11.3 13.6 12.6 11.1 9.3 7.2 5.0 2.5 Az0 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 .20 r sec Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 .CHANGE IN D I PJI a'ION OF GEOSTROPHIC y iNTD 29 Jl.1 59 63 72 78 82 83 3 6 8 11 13 1!t 1Z 16 - 17 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 The above Table shows that in the case of high wind velocities (i., e. in the presence of great preEsure gradient forces), the change of direction in the wind, with higher altitudes, is small. Inversely, in the case of mild winds, the change in. direction, with higher altitude, is sharp. or example, within the 1 - kilometer air layer, a wind with a velocity of 20 meters per second, will tern only Li. degrees, while a 3 meter per second wind, under the same conditions., will turn 28 degrees. Low-velocity Uainds, irrespective of their direction at lower level, will rapidly approximate the isotherm at higher altitude.. in the presence of great velocities, the change in direction is slower. However, at great altitudes, in a homogeneous air mass, the air still has a tendency to move in the direction of the isotherms, since accretion of velocity in this case is great, but the direction coincides with the isotherm. ince the actual wind at great atmos :ieri.c altitudes frequently is not much distinct from the geostrophic wind, the predominance of the general westerly current, which is observed in the troposphere of the temperate latitudes, may be explained by the diminution in tomperatiire from the equator to the pole through out the troposphere. In the stratosphere, the western component of the c..rind diminishes with altitude, in conformance with the inversion of the thermal gradient. The above considerations make it l:~os?ble to reverse the order of comput..tion: by the altitudinal change in the velocity and direction of the wind, to determine the horizontal temperature distribution. For example .?- acord:ing to pilot balloon observations, bhe -22 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 velocity of the id_nd at the lower level equals C0 (Figure ioi), and at the upper level, it equals C. By determining vectorially, ~C=e- Q , we derive all the required values for the determination of the thermal gradient / in the contemplate: atmospheric layer. Indeed, the thermal gradient f' is perpendicular to 4 and directed to the left of it (in the northern hemisphere), and its magnitude is de- termined by the equation: fL1z (12) These considerations can be utilized in the extrapolation of synoptic charts. Given a network of pilot ballon observation points, it is possible to get :adequately corn; fete data on the pressure and temperature distribution beyond the cut-off of the synoptic chart. However, in the practical application of these deductions, it must be remembered, that all the above said relates to the geostr.ophic wind, and therefore, it holds true only for 'homogeneous atmospheric layers, located outside the ground turbulent zone, i. e. for atmos- pheric altitudes in excess of 500 - 1000 meters. Figure 101. ~etermi.nation of the horizontal temperature gradient by the attitudinal changes in the gelstrophic wind Lean be studied from original texg. 23 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Section ).. Variations of Temperature and Pressure in Tine with Relaton?to the Altitudinal Change of Direction of the Geostrophc Wind. The variation in the temperature of. the air at a given point can be expressed by: a T = dT_ ?T _ aT aT at dtf u ~y- v a y - zu ~Z (1) Assuming that the air.masses are shifting without a change in dT I temper Lure, i. C. -= 0 . Then, due i to the geostrophic wind being horizontal: - ? ~ ---- -- -- & --j ------ C ~Gos~ /) Converting; to finite increments, we derive { where is the temperature variation for a unit of time, and (9) is the angle between the thermal and the pressure gradients (or be- tween the isobar and the isotherm). The angle is counted off from the pressure gradient to the thermal gradient. From (2) it can be seen that the change in temperature with time, which is taking place at a given point, on account of the inflow of air with a different temperature, is in direct ratio to the thermal gradient and wind velocity, and also to the sine of the angle formed by the wind.direction and the isotherm. The direction of the wind is . determined by the mutual disposition of the gradients: if the thermal Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Assuming at a certain height h, the pressure Ph being constant, we will, from the barometric equation which is true in the case of the geostrophic wind, derive by differentiating by t: Ar or, by substituting for --, as per equation (3) : Equation (6) shows that, in the case of a right rotation of the d9 wind with height (- 0 - v < Q 2 Southern hemisphere o > 0 t - v~ > 0 ' < o fa? oc Figure 110 shoves a diagram of the values of the geostrophio wind at a front. We see that the discontinuity of the wind has cyclonic characteristics both for the warm and the cold fronts. We thus obtain a result which is in conformity withthe behavior of the iso- bars in the vicinity of a front. It must be kept in mind, however, that the rule derived for the isobars was derived with complete rigidity. It is, therefore, true for all fronts without exception while the rule for the wind was derived only after a series of simplifkying assumptions, and is, therefore, less rigid. In individual cases it may occur that the horizontal accelera- tions are so significant that they will change the cyclonic rotation of the wind at the front into an anticyclonic rotation. However, such cases are rare and of short duration. . Thus, any front may be detected by the cyclonic rotation of the wind, irrespective of the circumstance as to What type of aix mass lies to, the right of the front, and what type of air mass lies to the left of it. In determining the relative displacement of air masses at a front the following rule may be followed Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 'If the observer facing the front is being displaced together with one air mass,the second air mass lying late is true in the case of any air mass and any front, displaced,,with relation to the observer, to the left Let us finally note that during direction of the wind at a given point changes "the wind turns to the right1'. (Figure 114) Figure 114. During the passing of any front the wind with tins turns to the right. However, even though a front is accompanied by a wind rota- Lion, it does not follow that any rotation line of the wind is a front. A line of rotation of the wind will be a front only in that case when there is present a locality of discontinuity of density what 1L4)79, or, is the sameA a discontinuity of temperature. Section 6._ Change in Gradientind with Hei ht, in the Area of a celeration in passing from a cold mass into a warm mass is in with a sudden shift, it being the case that the vector of wind ac- wind distribution along a vertical line. This formula shows that in its ascent through a frontal surface the gradient wind changes Equation (1) in Section 5 may be applied to the analysis of Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 direct ratio to the incline of the front fan d( and to the jump in, temperature at the front and is directed parallel with the,line of the front in such a manner that the wedge of cold air remains, to the left and the warm air remains to the right. This rule follows from the analysis of the problem on the rotation of the gradient wind; with height in a homogeneous air mass.(Chapter XI). In the case of a warm front tai 7? 4 (Figure 115, A),, and,. consequently4V=U --'dos i.e?, before a warm front the gradient wind sustains a discontinuity in such a way that the rotation of the wind with height in the area of a front is to the right (Figure 115, A). In the case of a cold front, &D1 Q O, and LI = Therefore, behind a cold front the rotation of the wind with height at the frontal surface is to the left (Figure 115, C). Figure 115. Change in wind with height in the vicinity of a front (a) warm front, (b) warm air mass; (c) cold front. . , dp,ps ' Whirr -- -,_ Fl ure // # tr, utro~ o f wind ctf 'hc ra~va a vs~', Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 . Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 If the .front is stationary, the gradient wind with height becomes decelerated with a sudden shift, retaining the: direction of the cold current,or becomes accelerated with a sudden shift, or, finallyreverses its direction with a sudden shift. Equation (1) in Section 5.shows that sharply accentuated fronts with a significant discontinuity of temperature and a steep incline are accompanied by a considerable change in the gradient wind with height. And, inversely, fronts mildly accentuated in `a temperature field, and with small angles of incline are accompanied by a mild shift in wind with height. . Thus, radiosonde observations can be used for? the determinate tion of the location of fronts in the free atmosphere. But, together with that, as already mentioned above a sudden shift in wind -will indicate the presence of a front only when a discontinuity in density (or temperature) occurs. Therefore, radiosonde observa- tions can only be used as a supplement to temperature sounding. We shall also note that when the wind with height rotates to the right the height of the frontal.. surface is increased in the direction of the wind (Figure 115, A). When the wind with height rotates to the left the height of the frontal surface decreases in the direction of the wind (Figure 115, C). face of the first order with relation to density and the pressure gradient. Therefore, the tropopause is a discontinuity surface of the first order, also with relation to wind velocity, i.e., the velo- We have seen above that the tropopause is a discontinuity sur- city of the wind at the tropopause will change continuously. ,~, .~~. a R r. t r., 14 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 As is known, the tropopause under normal conditions is inclined to the Pole. Figure 116 shows the possible distribu~ Lion of the vuind T~vith height ' in the vicinity of the tropopause. Disposition of a Surface of 'Separation in a Non-Stationary Wind Fielde that at an initial moment a certain surface of separation is inclined to the horizon more steeply than a stationary surface of separation, the inclination of which is determined from. the formula (8) in Section 3, i.e., in Figure 117. Fure 11.7? Evolution of ;accelerations in the vicinity of a non stationary surface of separation, with c > c(a ?? Let us assume in addition that no perturbations are acting upon the currents. An elementary but cumbersome analysis shows that in this case a discontinuity of the acceleration components, normal to the front, occurs, it being the case that Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Ze i'.5 ,5S*d'1 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 7;~r4?tiei- ?a); phis r~edr' #; b'1 ~~r QCC' 1'/,ere aJ~G vcc J' 5 " Cara e ?' 'iscanr~inuI y oa dis- placed greater 7%2>>U o>2.>j of c.G~ d h >a>z < . z ~ Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 (-?IaPt . >u>O; ?>>O; for in . I Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 ascending currents developing in both the cold and the warm air (the ascending warrc. air overtakes the ascending cold air). The emerged normal components of velocity induce tangen~ tial accelerations which are predicated on the rotation of the earth. These supplerr~ntary accelerations in the first case have the same direction with the absolute value of the warm mass ac- celeration greater than that of the cold mass and with the warm air remaining to the right with relation to the cold air. In case No. 2, the air masses being considered are being dis- hoed toward each other, i.e=, both masses are moving toward the p cold air . front. It being understood that. the front proper will not undergo displacement only in the case when the accelerations of the air masses in their absolute values are equal to each other. If the accelerations in their absolute values are not the same, the front will underga~ displacement in the direction of the cold mass (when a = and in the direction of the warm mass (when ~~ ) ? In conformity with this the front may be stationary (when ._- 4 ) warns ~wh ~a I1>1u21J or cc/d (h I uz j) _ In this case regardless of the nature of the front an ascend- ing motion will develop in the warm air and a descending one in the Accelerations which are tangent to the front are of opposite directions and they contribute to the evolution of cyclonic motion at the front Finally.in case No 3, both air masses will be displaced in the direction of the warm rriass with the cold-mass ' sustaining a Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 II' Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 a Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 cold mass. The accelerations analyzed above result in that (1) either the warm air will overtake the receding cold air and rise at a greater vertical velocity along the wedge of the simultaneously rising cold air. Together with this the existing discontinuity in velocity at the front, will increase which circumstance entails' a greater angle of?inclination of the stationary surface of separa- tion. (2) Or the warm air will flow into the wedge of the descend- ing cold air encountered by it. In this case the present disoon- tinui-by in velocity will increase which circumstance also entails a greater value in the angle of inclination of the stationary surface of separation. (3) Or the cold air vdll flow under the receding warm air with the warm air in its receding . lagging in its vertical motion behind the. more rapidly descending cold air. The discon~ tinuity in the tangential velocities will also become greater, which circumstance will entail for purposes of equilibrium a steeper angle of inclination of the surface of separation. greater (in absolute value) acceleration than the vuarm mass. This motion will be accompanied by descending currents developing in both air masses, it being the. case that the cold mass will be descending more rapidly than the warm mass., The accelerations which. are tangential to the front w111 again bu in the ~same direction with the acceleration of the warm. mass in absolute value being 1o~uer than the acceleration of the In all cases as a result of accelerations the angle of in- cllnation of the surface of separation will be diminished while the q! .. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 intensified discontinuity in the tangential oornponent of wind t'~'GessiN/ velocity is increased so thatT' low-sloping surface of separation (Figure' 118) is already not in conformity with conditions of equilibrium. In such a case accelerations having an inverted sign begin to develop at the surface of separation which results in that either (i) both masses will be displaced in the direction of the warm mass descending at the same time with the warm mass, moving more rapidly and overtaking the descending cold mass, or (2) both masses will flow in different direotionsywith the warm mass descend-. ing along the wedge of the ascending cold mass, or (3) both the warm and cold mass will move in the direction of the cold mass, as- tending simul Eaneously)with the cold mass receding more rapidly, overtaking the warm mass along a vertical line. Together with this in all the above cases the tangential oom- ponen-ts of the generated accelerations have anticyclonic character- istics~ as a result of which, with time, the discontinuity in velo- city at the front is gradually diminished, and may even change its sign. The angle of inclination of the surface of separation will increase while at the same time for a stationary surface the re- quisite angle of inclination will already be smaller, Thus, we returned to the initial postulate from which we began our analysis. A more detailed investigation shows that a surface of separa- tion oscillates somewhat about the position of equilibrium which is not coincident with the position of a stationary surface but, deflected from the latter in the same direction as is the initial position of a surface of separation. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Fiell84 Evolution of aocelerations in the vicinity of a non- stationary surface of separations with c as Section 8. Classification of Fronts. The above described characteristics of fronts relating to their position in a pressure field, wind field, and temperature field, are applicable to both shifting fronts and stationary (mo- tionless) fronts. By these charaoteristics the presence or absence of fronts in a synoptic chart or in a vertical section may be judged. However, with relation to the movement of fronts and to the relative position of the warm and cold air masses and their stabi- lity it is possible to establish a series of additional character- istics for any given type of front. Thus, it becomes possible to classify fronts by their characteristics. Such a classification relegates a contemplated front to its proper type. Fronts may be classified by their geographic index. There are four basic types of air masses: arctic, polar, tropical and equatorial air, Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 are usually characterized by great horizontal' homogeneity in tem'- perature as a result of which no secondary fronts are evolved with'- Declassified Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Besides the general frontal characteristics, such as disconw tinuity in temperature discontinuity an the tangential oomponent of wind velocity and others which were discussed in the preceding g text and which are applicable to all fronts, there are no other particular` characteristics which would determine the geographical classification of the fronts. Nevertheless, the usefulness of such a classification is obvjous. Since the main fronts predominate over, the secondary ones, by the frequency of their emergence, by the vastness 'of the area occupied and by the duration of their exist ence,the clarification of weather data that is tied in with the ex- istence of fronts for the purpose of a synoptic analysis is con-. corned, first of all, with the primary fronts. Only in the case when a particular weather feature under analysis cannot be explained 's by the existence of the main front attention to be drawn to the secondary fronts. In so doing it is recommended to pay particular attention to the clarification of the processes promoting the for- mation, as well as the disappearance, of these secondary fronts. The most essentialclassification of fronts is their classificaw tion with relation to the characteristic of the novement of the front and the migration of the air masses. Within this classifi- cation there are 4.types of fronts: (1) A warm front, i.e. a front moving in such a way that the warm air displaces the cold air; (2) A cold front, i.e. a front moving in such a way that the cold air displaces the warm air; A stationary front, i.e. a front that is motionless; Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 ULLG vY Lj. t~1L ueang roreea out after a more rapidly moving cold front reaches a slowly moving warm front. .n occluded front is generated vuhen between the cold air receding before a warm front and the cold air advancing behind the cold front there exists a discontinuity in temperature. It can be shown that the movement of a front is determined by the formula When the vertical velocities w are very small it can be as- sumed with approximation that the velocity of the movement of the front is equal to the wind velocity component which is normal to the front. It is, of course, understood that in this case we are considering not the velocity of the surface wind but the velocity of the geostrophic wind which is observed above the friction 1eve1. Consequently a fast moving front must cross the isobars at an almost right angleawith the isobars themselves running adequately close to each others Stationary fronts must be parallel to the isobars. Strictly stationary 'fronts occur very rarely in the atmosphere. Very slowly moving fronts are encountered more frequently. Such a slow moving front called a quasi stationary front,greatly complicates the pro- blem of weather forecasting, since its subsequent movement is in this case there is no displacement of one air mass by anothex; (4) n occluded fronts i.e. a front generated as a result Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Therefore, the classification of fronts or surfaces of separation is done with relation to the behavior of the warm air mass There are surfaces of uppslope sliding or anafronts when 0 and surfaces of dovanslope sliding or katafronts, when w;L < 0 . Differentiating also warm (~ ,> D) , cold (c,c d) , the isobars are d splaced along the pressure worce (C. 0) , and in the area of negative barometric ten- gradient .L If s (T dA'L , the Ri number asymptotically approximates the Finally, Obukhov computes theoretically the change in the coefficient of turbulence' K with heights Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 But -- - -? , consequently ~- -- z . -the behavior of function , basically speaking, is known; therefore it is simple to investigate the variations of k(z) with re1ativr~ly small (as cornpax'od v/.'1,h L. ),and relatively great values of z. therefore when --> , then, with L , Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Further: 1(e)- r z~L when c_>? f ?t ; consequently, Thus, Obukhov arrived theoretically at the following result: with love values of z, the coefficient of turbulence K increases linearly with height, and with high values of z, the coefficient of, turbulence asymptotically approximates its ultimate value / uL If the scale L is eliminated from (30) with the aid of (17), k00 will be expressed thus; Obukhov computed the following Table of ultimate values ...,~ --1 /4 gram/centimeter second (Table 48). as Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Calories cm2 mmn 0.01 0.02 0.05 0.31 degrees centigrade/100 meters, grace/ Oo meters. 0.1 0.15 0.2 0.3 - As seen from the above 'fable, the values of the parameters of turbulence theoretically derived have the same order of values of these parameters, established from observations. . Obukhov cites the following example to show hove ~ve11 the theoretical values of the turbulence parameters coincide with their observational values: When uo~ 5 meters/second, u* 0,25 meter/second, and q 0.1 clorie/s uare centimeter, K~ ' 1.82 square meters/second, a ~. Air, a 22.4 grams/centimeter second L 18.2 rosters, -0.69 degrees centi- Table 48. Ultimate value of the coefficient of turbulent exohange Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 gram centimeter~1 second ~~ for a stable atmosphere. u me se 20 u* ter S/ cond u sec 0.5 2.5, 0.0224 Oe0112 1 5 O?3567 0.1722 2 10 5.7195 2.8536 3 15 28.905 14.514 . 4 20 91.512 45756 5 25 .11.684 30 10 50 0.00443 0.00221 0.OO15 0.0010 0.000738 0.0738 0.0369 0.0246 0.0123 0.0123 1.1439 0.5658 0.3813 0.2829 0.1845 5.781 2.829 1.968 1.476 0.98 18.327 9.102 6.150 4.551 3.08 44.895 22386 14.883 11.95 7.38 93 .l 11 46.371 30.873 23.124 15.38 X238.743 178.719 119.19 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 This example shows that the value of the temperature gra~ client computed by the theoretically derived value of Kam, also conforms well to observational magnitudes. Let us take note of the fact that in his computations Obukhov assumed a value for Ri ultimate that was obtained by Sverdrup from observations, namely; I (Ri) ultimate Section 3. Variation of Wind with Heig t and Turbulent Exchange in .the Planetary Boundary _Layer. One of the raost known manifestations of the effect of turbuw lence in the atmosphere is undoubtedly the variation. of the velo- city and direction of the wind with height in the lowest atmospheric layer. In a homogeneous air mass the increase in the velocity of the wind vrith height is manifested with perfect clarity, also its rotation to the right in the northern hemisphere, and to the left in the southern hemisphere. Such a change in the velocity of the wind begins at a height of 1020 meters, and extends in our latitudes to a height of about 1 kilometer. Below the level of 1020 meters the direction of the. wind remains constant and the velocity magnitude varies logarithiM mically or in accordance with the law of exponents. The change in the direction of the wind with height in the higher atmospheric layers is obviously stipulated by the combined effect of the deflecting force of the earth's rotation and turbu- fence . The layer in which the wind rotates with height, the Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 fW~ Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 rotation stipulated by the combined effect of turbulence and the deflecting force of the earth's rotation, is called the planetary boundary layer. `The most substantial characteristic of this layer is the angle , which is formed by the direction of the wind 'Z with the direction of the pressure gradient force (Figure 130)0 This angle "angle of deflection", . gl~ cc; rt/? 1 of is .k .own as the ~ s d;rzhi of /e '' fI)e u? /e ?jD d /e~h M ;s ~ail~d the :9 6f 1/ 71hc Figure 130. Angle of deflection and angle of inclination 9 of the wind, 1~;fhin the limits of the planetary boundary layer the angle of inclination of the wind is more or less substantially different from zero and the angle of deflection is always an acute angle. The magnitude of the angle of deflection is a function of the height As shown by numerous observations the angle of inclination of the wind depends not only on the height, but changes also with time (annual and diurnal cycles), latitude and orography of a locality. Thus, for example at the, earth's surface the angle of inclination of the wind is usually. smaller in the summer than in the winter, smaller in the higher latitudes than in the lower ones, u~ ip,t k;li gar Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R0001002200 1 7-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 smaller over the surface of the `sea' than it is over land. ire will now analyze theoretically the . change in the velo- city and direction of the wind with height under the effect of turbulence and the deflecting force of the `eartht s rotation. d~ Assuming the motion"horizontal and the field of velocities u d along a horizontal '"`homogeneous, we will proceed from the averaged equations of motion of the atmosphere which can be written down as follows dz 1 4 au d T : + O) Z) fit` z P r /) (1) c - dL %o ' r ~z: (- ?zJ Let us also make the following simplifying assumptions (1) The motion of the air is homogeneous and rectilinear, therefore d d~ d (2) The pressure gradient does not change with height. Therefore, directing the x-axis along the isobar, and the y-axis along the gradient, we have: Density does not change with height, i.e. /? M coast. (4), The coefficient of turbulent exchange 'does not change with height, i.e. A M const. ._.~- ~. Q Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Then, the equations of motion will assume` the following form: dz 2 ,I Now we f o rmul ate the boundary conditions: (1) At the earths surface there takes place adhesion of air so that lzs/7e.1 Z = (2) At great heights the wind becomes a geostrophic wind (U , ), consequ.ently, with Z-- cx --~ d ~ z'- r 0 The problem of integrating the system of equations (2) with two unknown functions Ua V , oan be reduced to the problem of integrating one equation but with a complex unimown. function W = zF:iv To accomplish this we multiply the second one of equations (2) by , and add the result to the first equation. ~ ar2~v dz a ?G (3) Thus, we obtain an ordinary linear differential equation of the second order with constant coefficients which can be re-written as follows: 4. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Consequently, the final solution of equation (4) is like this: 7.- {L, We now separate the imaginary and the' essential parts of solution (12). since consequently ' Applying the Euler formula Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 r we find 15) and finally e ('cos (fix c /i; aZ) -a C45 G Z~ : a c-' 1 -?--~ 2Le,e s?rr a Thus, we derived the components of wind velocity as func- tions of height z. We now find the absolute value of velocity 2 z and the angle of inclination if _ e - c( cos qZ (17) (18) Formulas (17) and (18) show that with the increase in height z, the velocity value increases and the angle of inclination diniin- fishes so that the wind approximates the geostrophic wind in magni- tude as well as direction. greater the value of GC's This 'process is the more rapid, the 71Li.e. the lower the turbulent exchange and the higher the latitude of a locality. From (18) it follows that at some heights the wind. assumes the direction of the ~eo str ophi e wind so that 00 with ~, The minimum he ight 51;9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 at which the `wind assumes the direction of the geostrophic wind, is called the level of friction. Although with subsequent in- crease in height the wind is somewhat deflected from the direction of the geostrophie wind, these deflections are so small that practw ically they cannot be detectedy as can be seen from Table 50. Therefore, the level of. friction which is determined by equation (19) can be. accepted as the upper limit of the planetary boundary layer. Table 49 gives the thickriess of the planetary boundary layer for various values of the coefficient of turbulent exchange and -3 -3 latitude vuith 1.25 x l0 gram centimeter , Table 49. Level of friction with coefficient of turbulent exchange constant. 100 300 50? 600 9Q0 1 -1. - sec 10 gram cm 790 470 380 350 330 50 1770 1040 840 790 740 100 2500 1470 1190 1120 1040 150 3060 1800 1460 1370 1280 As can be seen from formula (19) and Table 49, the level of friction is the higher, the greater the coefficient.of turbulent exchange and the lower the latitude of a location. The velocity value at the level of friction Which is ex- pressed by formula e J>Z4;$) ???(20) Irj''11h'' byp Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 When Z >00 -- ' t When z= O formula (18) results in an undeterminate form of the type Evaluating it in accordance with the LtIEIospital's y rule we derive s d -~z .Y d.#.~... (e sir- c(z) ~-ar G ~ aZ z o d..... (J-eos!) Thus, at the earth's surface the arngle of deflection under all conditions equals 45 degrees height in the planetary boundary layer. 4 ~a -'J/ is greater than the velocity of the geostrophic wind since is an essentially positive magnitude. Thus, the velocity of the wind attains in absolute magnitude the velocit3r "value of the geo- strophic wind somewhat below the level of friction. Assigning definite values to OC. it becomes possible to eom- 4ji(17,hz 2a(/~) C puce the corresponding values for and -- . Assuining that 9 : 450, :: 10- gram,/em3, A " 25.2 gram crn sec and, con- sequently O( = 0.004775 m, we derive the following Table of values for and' for various heights (Table .50)? and the wind becomes geostrophica 10 20 40 100 200 400 . 800 1200 m 0.075 0.145 0.286 0.584 0.893 1.068 1.005 0.999 43 42 39 31 20 5 -1 0 Table 50s Variation in the velocity and direction of the wind with Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 In constructing by table. 50 a diagram of the, wind velocities as function of the height z, we derive a spiral which is known in geophysics under the name of the Eckman spiral (in honor of Eck- direction of ocean currents under the effect of turbulence and the logarithmic spiral with an angle of 45 degrees.. It passes through the origin of coordinates and approaches asymptotically the point Figure 151. The Eckman spiral. shown` that under the combined effect of the Coriolis force end turn bulence, the velocity of the wind increases with height, simultane- ously turning to the right (in the northern hemisphere). At some height the wind becomes equal to the geostrophic wind, first in magnitude and then continuing to increase at some greater height becomes equal to the geostrophic wind in direction. At the earth's surface the angle of deflection is always equal to 45 degrees. Accumulated empirical data shows that the factual mean.dis-' tribution of 'the wind by height at an adequate distance from the earth's surface., concurs well with the theoretical distribution, Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 but in the :lowest dekameters there is no such concurrence. Thus, at the earth's surface the angle of inclination of the wind is considerably less than 45 degrees and in addition:it does not rem main oonstant, but varies within rather wide limits, decreasing over the sea during the summer and during the day and increasing over land during the winrber and during to night The factual magnitude of the wind velocity at the anemoscope :i,evel is consi- derably`above its theoretical value The subsequent efforts of the soientists were directed toward the further development of the theory relating to the change in the wind with height, the beginning of which was laid by the work of Eckrnan and Okkerblor. . Gessel'berg and Sverdrup took into account the change with height in the pressure gradient forces considering this change as taking place in accordance with the linear rule, but assumed, as before, than P and A are constants. However, they completely excluded from consideration the layer below the anernoscope levely assuming justly that conditions of turbulent exchange predonr.nat- ing there are different from those in the layers above. With the indicated assumptions, Gessel'berg and Sverdrup laid out a model of Wind distribution with height, which concurred well with results of observations. Figure 132 shows a rectified (in accordance with Gessel'berg and Sverdrup) Eckman spiral for the atmospheric layer above the level of the anemometer. For comparison purposes the same Figure shows a spiral constructed as a result of developing the data obtained by 99 observations in Lindenberg. Figure 133 shows the distribution by height of. the l";f Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 absolute magnitude of velocity, obtained both theoretically and Figure 132. The Eckman spiral for the layer above the anemoreter. The solid line is the mean of all observatjons9 the dotted line - the mean of all computations4 Figure 133. The absolute magnitude of wind velocity as a funetio?n of height above the anemometer. The solid line is the observation our, the dotted line M the computation curve. The research by Gessel 'berg and Sverdrup substantially im- Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 proved the Eckman-Okkerblorn theory. However, the solution they arrived at is by far not an exhaustive one. The change in the angle of inclination with relation to the time of the year and orography Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 A considerable contribution to the solution of the con- ,-em fated problem Was made by the labors of Soviet scientists, which we are going to analyze in the Section irnnedia e1y follow- ing. Section 4. Variation of Wind with Height iii the hePesence of a Variable Coefficient of Turbulent 'exchange. The state of turbulencet any point is determined by one number- the coefficient of exchange. Having assumed in the pre- g .. paragraph that the coefficient of exchange was the same for cedin all heights, we have by the virtue of this accepted the state of turbulence as the same for all heights. Yet, the state of turbulence and, consequeltlY, the coeffi-' dent of exchange in the atmosphere are subject to considerable variations. The principal factors affecting the value of the co- efficient of exchange are : the velocity of the ge o strophi c wind ( or the pressure gradient that determines it), the roughness of the underlying surface, the stability of atmospheric stratifioar Lion vertical temperature gradient), the height above the earth? $ surface, Since the coefficient of exchange is not measured three' ly, but is computed on the basis of measurements of other moteoro- loggical elements, it follows that a correctly assigned character of variation of the coefficient of exchange is very 'important to such computations. The assumption of constancy of the coefficient of exchan e by height, in, some cases, does not allow the correct g evaluation from observations of even the order of rnagnx.tude of the coefficient of exchange. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 On the other hand the assumpbiofl that the coefficient of exchange in the entire planetary boundary layer increases accord- ing to the linear l.aw leads to incorrect results, namely; to ex- cessively large values of the coefficient of exchange. ?In their latest works, Soviet' scientists use one of these two computation patterns, outlining the variation of the coeffi- cient of exchange with height. l~atbern A; the coefficient of turbulent exchange increases with height asymptotically approaching the constant value. . e_m) (1) Y ~ where #)' 6 is molecular viscosity. This pattern was suggested by B. I. Izvekov. Pattern B: the coefficient of exchange first increases with height according to the linear law up to a certain height h, after which it remains constant, i.e. : . ch, whz}h, ~ Pattern A is deficient in the sense that its use leads into more complex computations. Pattern B is more convenient for corn- utntions although it leads to the solution of a two-layer problem. p In this Section we will analyze the problem of the varia- tion of wind with height, 'accepting, pattern B as the coefficient of exchange. This pattern was first suggested by M. E. Shvets and Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 M., I. Yudin who derived an adequately simple and precise solution of the contemplated problem. Yudin and Shvets, assuming the motion to be homogeneous, proceed from the following equations Multiplying the second equation by i, subtracting result froxrL first, and interpolating the complex velocity the two equations (3) are reduced to one Equation (.5) is rewritten in the following form; height. I?t. is assumed that the pressure gradient does not change with Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 This is one of the forms of the well known Bessel r s equa- tion, which is integrated by the use of special sopcalled cylindri- cal functions which have been extensively studied: gration constants, which are determined from the boundary conditions; Io is a Bessel function of the zero order; No is a Neumann function of the zero order; ~,~~~^ the eostro- ?2c::)@Y phic wind. For the layer above level h we derive the Okkerblom solu- tion already analyzed before: where A. and B are arbitrary integration constants, which are deter- 2 om the bo min d f d d t e r un ary con i ions and = Yudin and.Shvets assume the following boundary conditions:. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 (3; At infinity the force of friction is finite: C'(a~ ~z . )/ it being the case that the value of arbitrary constant is determined from condition (27). Shvets and Yudin computed several examples of the distribu.. Lion of wind with height, assuming the following values for the parameters: imaginary part we find: ir j z Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 3.88 5.75 12.8 20 6.62 0.1 0.1 0.1 0.1 0.1 0.077 3.44 3.82 42.3 20.9 10.52 m/sec 190 lvi 1.77 m2/sec The analysis of Tables compiled by the authors led them to formulate the following deductions resulting from theoretical re-i search and agreeing well with observations (1) The angle of inclination of the wind is increased with the increase in the roughness of the underlying surface. (2) Turbulent viscosity is increased with an increase in the pressure gradient. (3 ) ,The velocity of the vlind at the height of the anemometer is about one half of the geostrophic wind velocity. (4) yith increased height the wind in magnitude and direction approximates the geostrophic wind, it being the case that the velocity magnitude attains the geostrophic value before the direction does., (5) lAlith greater turbulent viscosity the angles of inclina- tion are smaller. (6) In the case of winds of great force the height at which the wind attains the geostrophic values is greater than in the case of mild winds. meter height and the velocity of the geostrophic wind, is tied in (7) The ratio between the velocity of the wind at the anemo. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 vlith this velocity, roughness of the underlying surface and the angle of inclination. With a decrease in any of these 3 values, the above ratio is increased, (s) At some heights the value of the velocity of the wind exceeds the value of the velocity of the geostrophic wind at the earths surface. Section 5. Diurnal Variation in the Velocity of the Wind. The diurnal variation in the velocity of the Wind is tied in with the At the earthts surface under conditions prevailing over a plain the velocity of the wind has a clearly pronounced diurnal variation unless this variation is disrupted by perturbations, which are stipulated by changes in v'eather. The wind is at its lnaxirnurn velocity soon after middayd At night there is a wide minimum. The angle of deflection of the wind from the isobar is at its minimum during the day, and at its maximum during the night, season of the year, the underlying surface, and the air mass, the surface of the sea this diurnal variation is almost completely absent0 summer when turbulence is greater , the height of rotation attains 300 on the season of the year and the force of the wind. During the Above a certain level the velocity of the wind has an inver-b ed diurnal variation: the maximum is observed at night and the minimum during the day. The height of rotation of the diurnal vari.a- tion of the velocity of the wind varies within wide limits, dependent meters, while during the winter it is only 30-50 meters, Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 A computation shows that the diurnal variation in the velo-city of the wind cannot be explained by the diurnal variation in pressure since wind velocities induced by the diurnal variation in pressure do not exceed 10 centimeters per second, while actually observed diurnal wind velocity ranges are tens of titles greater than the above indicated value 0 On the other hand, the enumerated pecul.iar?iti.es of the di- urnal variation in the wind indicate clearly that the _di.urnal vari- ation in the velocity of the wind is tied in yvith the diurnal van-' ? ~. ation in turbuience a The first attempt to explain the diurnal variation in the velocity of the wind with the aid of the equations of hY? drozrnechan' zcs was made by B. I. Izvekov, He considered the kinematic coefficient cf turbulent viscosity as non-varying with height, but as a periodi- cal function of time. where is the mean diurnal value of tlie kinematic coefficient G of turbulent viscosity, 6 is the diurnal variation amplitude of this coefficient and W is the angular velocity of the earth. However, having assumed the coefficient of turbulent viscosjM ty as non-varying with height, Izvekov arrived at rather unsatis- factory results. The velocity of the wind, as per Izvekov9 does not approximate with height the velocity of the gradient wind. The condi'taon cif the air adhering to the earth's. surface also remains unsatisfied, Finally, the rotation of the diurnal variation of wind velooity at the upper levels of the boundary layer is also absent, Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 1 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Pzm=Ae -2wxc G~? where A is the arbitrary integration ccnstant. It was also shown there that after determining the arbitrary constants of integration there remain two equations tying in three magnitudes s'C(t) /L&), o (, where G(. is the angle between the direction of the wind and the direction of the isobar at the earth's surface . These equations can be ~vritten like this: 1J2"n t ~L ~a z. J J2 I~( zo %oo J ..-4 _. z I. - -....~.-. rn e 4jz where -J ~r i j a = (k. Jz ~d Z a nz t c when Z k) (10) wk ) LIN0'(yf;I) (12) Eliminating from equation (ii) angle 0Xwe derive one equa-' tion tying in ) and k(' 4 0 2 ,, ' z_(G ) Z (13) (2L::L ,J.2 ,. ( * Jt iR Accepting as the coefficient of turbulent viscosity ) at a height above the level z ^ h,? the condition = c(M(&,)= (ZtEs.1n )2), Shvets determines c(t and h(t) from equations (13) and (14), 14) then by the Tables he constructed he derives the distribution of the wind with height, Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 matic characteristics of rule (it), Irrespect%ve of the sche . iciont of turbulent viscos~.ty with the vara.ations a~' the coef f b~ ~hvats, will agree wa:th obser- time, as derived theoret~.cally :r vatianal values. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 CHJ PTER XTII THE ENERGY OF ATMOSPHERIC 1VIOTION3 Section le Transformation of .ergy in the 'Atmosphere? For the atrnospheric processes under study in dynamic meteor- ology, the following forms of enemy are of" essential significance: (1) Radiation energy (R); . (2) Kinetic energy of averaged large scale currents of the order of general circulation or currents in cyclones and anticy- clones (E); (3) Kinetic energy of the turbulent motions which is. tied in with the presence in the averaged currents of additional veto- cities (Es). . (4) Potential energy of th,e air masses (TI); Internal energy of ai r (U). We are not concerned here with. electric and magnetic energy, which have considerable significance for some individual phenomena in the atmosphere, but for the processes under study in dynamic meteorology, are not essential. The potential and internal energy of the air are in direct ratio to temperature T; therefore, as will be shcwn below there is,. a close and direct relationship betvueen there to to 'effect'that the increase in the internal energy of the atmosphere is ?always accompanied by an increase` in its potential energy and vice versa. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 A continuous transformation of energy from one form into r one is continuously taking place in the atmosphere The anothe basic mechanisms for wuch trasfo rn~ata on are absorption and radix' tin, mechanical work and the dissipation of mechanical energy into heat . The following transformations of energy are possible in the atrosphere 9 - >(Ufr E >.(u E '- (U (Ut ) , (u~ ) -> E_ (U*7T)a Radian on energy cannot be converted into kinetic energy directly. It has no significance for the atmosphere until such time as the atmosphere will absorb it, i.e. until such time as it Will be transformed into internal energy! It being the case that in atmospheric conditians (in a gravitational field) an increase in internal energy is always accompanied by an increase in poten- tial energy, therefore, I'LT, I77) Internal energy can again be transformed into radiation energy by way of atmospheric radiation, it being the case that a decrease in internal energy is alway$ accompanied by a corresponding decrease in potential energy The internal and potential energies, accumulated as a result of absorption of solar radiation, may subsequently be transformed into kinetic energy Which sometimes assumes the form of kinetic scale motions (J#7T).-*E, or the form of kinetic energy of large .. w u4.~~~ r Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 ' 4 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 energy of turbulent motions (U)E. The transformation of potential and inbernal energies into kinetic energy is one 'of the most important aspects of modern _dynamic meteorology, since the general circulation of the atmosphere and the evolution of cyclones and anticyclones are specifically' tied in with such trans' formation. In its turn kinetic energy may be transformed into pa- tential and internal energies either by vray of direct transition of kinetic energy into potential E y (C/t T1~. by way of dis- sipation of mechanioal energy into thermal energy. In the latter case, the gradual process of degradation of kinetic energy by vray of the breaking up of vortices takes place. The kinetic energy of large currents is converted into kinetic energy of progressively smaller vortices E'E " until such time as it is dissipated into heat energy under the effect of viscosity ,f -f? .. The process of transformation of kinetic energy of large currents into turbulent kinetic energy is an irreversible processe A process which would lead to the straightening of the lines of flow and to the increase in total velocity of a current at the expense of a diminution in the velocities of the additional motions is not possible in nature. .ection 2,. Equation of the Ener balance of an Individual Air Particles Let us develop the equation of the energy balance 'of an in- dividual air particle having a' mass equal to unity. We.. will assume that frict ofl is completely absent, and the air is in motion as the ideal liquid. In this case the equations can be written 'down this way: ;2I " Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Multiplying equation (1) respectively by t Z/ W and adding the results we derive the equa b.on of the mechanical energy balance or the equation of live forces; dt (2) is simplified, dt P a~ dv - s aP 2 w Stn E'p where c is the velocity of the wind, is the component of the pressure ascendent in the direction of velocity. . 'iVe note that the deflecting force of the earth' s rotation did not orr er the equation of live forcoS,,vahioh was to be expected since the amount of work performed by the force of inertia is iden- tically equal to zero, due to the direction of velac?ty and the force of inertia being perpendicular to each other, Uthen the motion is horizontal (fz)C , an equation d~ . d d(zJ ../o ~5 It follows from equation (3) that if pressure drops in the a r is increased of t she motion >ororlni..ts m, Izvekov, and Shvets repeated the com- putat,:i.ons for theconstruction of the Kochin model of zonal circulation, proceeding from a more perfect sir tern of equations and basing themselves on new data for temperature and pressure distribution. They succeeded in proving that, in the case of zonal circulation, there are present in the atmosphere 3 basic "rings" of a distinctly pronounced circulation in a vertical plane. The tropical and the polar rings are of thermal origin. Teynoperate" as simple thermodynamic machines. The heaters are below at high pressure, the refrigerators are above at low pressure. The middle ring of the temperate zones is of dynamic origin. At the belt of high pressure (in he horse latitudes), the meridional currents di- verge, and the loss of mass is comInsated by descending currents. In the I low prey ure belt (in the subarctic) the convergi A currents are compen- sated by ascending currents. Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 frad t _7/ $r d - , I ,O F- 2/ vJ . ( i) .Get us remove the vortex from both parts of this equation. Section 9. T'he_Hydrorl., ,arni c ~l~eory of pressure eaves and A-~mos~here; E. N. Bliriova analyzed the problem of long tend forecasting of pressure, temperature, and. wind, proceeding from the equations of hydromechani_c s. The results/ which she obtained consti tu:t,e a valuable contra bution in the co3tructio1 of mathernaticaT theoxr of the general circulation of the atmosl:here. The earth is consider :d as a globe having a radius c~ . The gravitational force and the Coriolis force at upon the atmosi'here, 1 !hc force of friction is assufi~ed. not to exist. A5 the initial equation the Fridman equation (16) from Section 1, Chapter IX is utilized. It deternnnes the change in the vortex vector of a given particle of 1?- quid. In order to derive this equation, we take Luler's equation in its vectorial form Assuming tai V , we derive the following equation, which is the Fric1 an ecuati.on: - rya' T2 Tr () 7w Converting to coord:i hate equations, Clinova interpolates the fol1owi.ng spherical coorclinatesc r -. the dista f nce rom the center of the ear'ti1 - the co-latituc e ( at the no.: tli Polo, nn at the south. pole ) , anti - the longitude of locat:i on . Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 The problert~ considers the motion of the ,atmosphere as consisting of Lhe basic motion, w}ich is the zonal circulation, and the perturbations of this motion herefore, the component velocities along and )- , and pressure can be taken as P-p(B~tp(B Let us note that here, as well as i n the :[urther procedure, all axes 8 values are averaged with relation to height. All the elements of are considered. small. Assuming that where is the angular velocity of the air in its motion relative to the earth, but not depend on . The ratio. is called the circulation index. Considering ?r,h.e v1ind as a gradient wind, we obtain the follotiling formula for pressure Mlle temperature formula is taken as foli..ows r= 1- r ltT?~a,~, t~ Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 where ?is the mean (monthly or seasonal) temperature distri- bution, stip1ated by radiation, turbulence, and di_Sposi t.ion of conti- nents and oceans. This distribution is considered. as fixed, with the zonal temperature given by the formula which is analogous with formula (5) for zonal pressure: 77)T-)-4f5;2O (7) , where and iW are constant magnitudes, 7it is the departure from steady temperature di.stributione 1agnitudes rand r ich express the perturbations of the zonal t.em .erature, are considered small. Assuming that there are no vertical velocities, and disregarding the variatiGns in density, t~linova interpolates the stream function ) , proceeding from the equation of ontinuity It is obvious that the stream function ' for a small perturbation may be presented as the sum of 2 star'earn functions O( A1 ) =- '( A) -1 92 " t,) is a stream function, which is not dependent on time, and it expresses the steady part of the perturbaT,ion0of~r zonal circulation. 'Ihi.s function is stipulated by the presence of the steady perturbation. of the zonal temperature di stri1:uti.,on, expressed by term A in 1 equality (6), and is the stream function expressing the non- steady perturbation of zonal circulation. ny~ . , 1.._. , ?- t: ', ,r. ,.. 1. .., .., ,.f , . ,: W s Y Fv. :L' ,.~. .ti ., ~,.., ..- v. '... r. r,n , ~.. ,. ,. ,,:,.. ... ,. _, , ..,.;... ,, .. .,. s .r..,. ,. i. r ~. -t _..b.m . ~i? t, -. .. ~,. ,.n: ,;XI,a v. k. .. ~ 1:'. .~a., ., .. ... .. ...... .,.., ,. .. .. h .4. .r ,. r:. 4C re. .~ f....k. 4. ., _., F-e~ .... ,. ~,. ~,~. .. v. .... .' ... . , u .~. ~ ,.. .._ ' . r 'l. ' 1. . .. n,. t. - w,.: . f W. I. aY.C. ,Cs ,. r?. R. ~:., d,, .,w. ,, .c ,a -.,,i' w, ,,. Ar,. .. ~:~.... , .r ,w t. ,. 6...e r .,n.?qs ~ .:>...c.N, .rk.Mw.,, ..~,,ux.e hl~,a9sr:r s ,u*.. Pl+aSw.,, ..v ...a, roz rdu `P'.am.4nYt,u~v,ur P4:.J,,,,PA P9~~kaxrl#,d.~~M kaz. d.l~iW:~lFrt3 ..w?r... Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 Declassified in Part - Sanitized Copy Approved for Release 2012/03/23 : CIA-RDP82-00039R000100220017-9 2 ( ~) $a~ B ~ ~J t 2,~aC ~Gt~) e'en 8 The equation of motion, taken for axis , has the form of Finally, l linova takes the equation of heat inflow in the form of Dy the same token, the pressure perturbation t is taken f 1 as the sum of two components: which is the steady perturbation of zonal pressure di. stributio~rt, and t~ t), ih ich is thy' / e non-steady perturbation: By projecting the Fridman equation (2) onto axis r, by substi- tutang the velocity components with the respective derivatives of the stream function, and by disregarding the small terms, J3linova deri..ves 0 ?he followJ..ng basic equation of the i. rcblen She simplifies somewhat this equation by d.isreg