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CIA-RDP85T00287R000600580001-4
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RIPPUB
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S
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18
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January 12, 2017
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July 19, 2011
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1
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May 13, 1983
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MEMO
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Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 .' " ?' 4Y 1333 MEMORANDUM FOR: -(See Addressees List) FROM: 25X1 1e , Strategic Resources Division, OGI SUBJECT: PRED: A Predictive Weather Model for Crop Forecasting 25X1 1. The attached memorandum describes a new weather forecasting model which will be used primarily in future assessments of the Soviet grain crop. 2. This paper was prepared byl ~ Agricultural Assessments Branch, Strategic Resources Division, Office of Global Issues. 3. Comments and queries are welcome and may be addressed to the Chief, Agricultural Assessments Branch, on Attachment: PRED: A Predictive Weather Model for Crop Forecasting, May 1983, GI M 83-10129 25X1 25X1 25X1 25X1 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 SUBJECT: PRED: A Predictive Weather Model for Crop Forecasting Mr. Elmer Klumpp Special Assistant to the Under Secretary International Affairs and Commodity Programs Department of Agriculture Dr. Terry N. Barr, Acting Chairman, World Agriculture Outlook Board Department of Agriculture Mr. . Jimmy Murphy Acting Assistant Administrator International Agriculture Statistics Department of Agriculture Mr. Donald J. Novotny Director, Grain and Feed Division Foreign Agriculture Service Department of Agriculture Mr. David Schoonover Director, Centrally Planned Economics Division Foreign Agriculture Service Department of Agriculture. Mr. Gerald A. Bange Director, Foreign Production Estimates Division Department of Agriculture Mr. Anton F. Malish Chief, USSR/Eastern Europe-Branch Economic Research Service Department of Agriculture Mr. Keith Severin Foreign Production Estimates Division USSR/Eastern Europe Department of Agriculture Mr. Frank Game Foreign Agriculture Service Department of Agriculture Mr. John Danylyk Bureau of Intelligence and Research Office of Economic Analysis Department of State Mr. David Peterson Director, Office of Intelligence Liaison Department of Commerce Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 I I SUBJECT: PRED: A Predictive Weather Model for Crop Forecasting OGI/SRD/AAA I(13 May 1983) Distribution List: (Attachment with Each Copy) Orig - Each Addressee 1 - D/GI 1 - DD/E 1 - DD/SOVA 1 - C/SOVA/SE 1 - SOVA/SE/R 1 - C/ECD/CM 1 - C/SRD 4 - C/SRD/AA 8 - OGI/PS Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 I I Central Intelligence Agency DIRECTORATE OF INTELLIGENCE 3 fi~~AY 1x33 Pred: A Predictive Weather Model For Crop Forecasting Sutunary The estimation of grain output in the USSR will be significantly improved this year by the introduction and use of the PRED model. In the past the estimation of crop yield has been handicapped by the lack of a reliable predictive weather input to UPSTREET's agronomically based, weather driven, crop-growth simulation model. In the absence of this essential data, analysts could only forecast the maximum yield. This required an evaluation of the impact of elapsed weather on crop yield and the assumption that ideal growing weather would prevail for the remainder of-the season. With the completion of PRED, which has the capacity to produce representative weather data for an entire season, the acceptance of the ideal weather assumption is no longer necessary. Furthermore, the accuracy and utility of the assessments produced during the early season are enhanced. In this report the use of the PRED model, as an adjunct to the UPSTREET analytical effort, is examined and evaluated. This paper was prepared by thel (Agricultural Assessments Branch, Strategic Resources Division, Office of Global Issues (AAB/SRD/OGI). Comments and queries may be addressed to the Chief, AAB/SRD/OGI 25X1 25X1 L_ 25X1 25X1 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 PRED: A Predictive Weather Model for Crop Forecasting PRED was developed to provide predictive weather inputs to the crop model used in the UPSTREET analysis of grain production in the USSR. By its calculated employment of historical weather data to determine the likely character of future weather, beyond the date on which the crop model is run, PRED provides information that has previously been unavailable. By generating a variety of representative weather scenarios, an average, (i.e. best estimate) crop yield can be determined-as well as information regarding the uncertainty of this estimate. This approach enhances the applicability of the UPSTREET methodology and lends credence to assessments of crop production made early in the growing season. The following sections describe the PRED model. Section I describes how the historical data is processed and details the creation of 200 independent, season long weather scenarios. Section II describes how a sample of weather scenarios (typically 25) are selected from this collection of 200 to reflect specified long term weather projections; Section III then describes the calculation and analysis of summary weather and crop-yield statistics. Section I: Data Collection and Assembly The first section of PRED compiles historical weather data2 to provide a base for generating parameters to describe weather conditions and develop weather scenarios. The historical weather data base includes at least eight years of information on daily maximum and minimum temperatures, precipitation, and evapotranspiration (ETP) for up to 3000 locations. To create future weather scenarios, the historical data are processed according to a serifs of statistical routines which establish probabilities, expressed as curves , for the following weather parameters: o occurrence of precipitation 1 UPSTREET - The UPSTREET methodology is an interdisciplinary approach to grain production forecasting developed by CIA. It was first employed to forecast Soviet grain production in 1975. The methodology is dynamic and improvements are made nearly every year. 2 The historic weather data is obtained from ETAC, the Envirormental Technical Applications Center, of the US Air Force. 25X1 3 ETP - The potential mount of moisture lost because of the combined effects of evaporation from the earth's surface and transpiration from leaves and other parts of plants. 4 These are actually cumulative probability curves with, for example, maximum temperature values on_ the x-axis and cumulative probability values ranging from 0 to 1.0 on they-axis. Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 o amount of precipitation o maximum temperature level o minimum temperature level o ETP There are two sets of probability curves for the temperatures and ETP: one for days with precipitation and one for days without. For maximum and minimum temperature and ETP, probability curves are derived for each half-month period in the year. For precipitation amount, a probability. curve is derived for each month. From these probability curves, 200 weather scenarios are created. The occurrence of precipitation, temperature, precipitation and ETP values for each day are selected from the probability distributions using a randan number generator. It is assumed that these 200 scenarios are a representative sample of all possible weather situations, given past history. In the second section of PRED, a subset of scenarios, usually 25, is selected to represent the weather at each location and to serve as input to the crop model. Each scenario created in Section I of PRED is characterized as above normal, normal, or below normal in terns of both precipitation and temperature. Scenario selection is initiated by the user who provides forecasts for each location. These are usually monthly forecasts but can be for any interval of time. The user can derive forecasts independently or use forecasts that are available from several universities and the National Weather Service Long Range Predictive Group. Each forecast consists of four declarations: o temperature - below, near, or above normal o confidence - a subjective probability that the temperature will actually fall into the above categories . o precipitation - below, near, or above normal o confidence - a subjective probability that the precipitation will actually fall into the above categories. Since weather is never totally predictable, this type of declaration lets some of the 25 scenarios chosen fall outside of the forecasted precipitation and temperature categories. Table 1 presents some examples of scenario selection for different forecasts. For example, if the forecast is for near normal temperatures and near normal precipitation,' with 90% confidence levels for both forecasts, then the vast majority of the scenarios selected will be normal in both temperature and precipitation. With the same forecast but only a 60% confidence level on both forecasts, only five of the scenarios selected will be. normal in both temperature and precipitation. As the confidence level decreases, the dispersion in the scenarios selected increases. 25X1 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 I I Examples of 25 Scenarios Selected for 3 Different Forecasts Number of Scenarios in Each Example Forecast Temperature Precipitation Class Example 1 B N A Near Normal Temperature (N) B 0 2 0 Near Normal Precipitation (N) Precip N 1 19 1 with 90% Confidence on both A 0 2 0 Example 2 B N A Near Normal Temperature (N) B 2 3 21 Near Normal Precipitation (N) Precip N 3 5 3 with 60%.Confidence on both A 2 3 2 imp Example 3 B = Below Normal N = Near Normal A = Above Normal B N A Above Normal Temperature (A) B 2 1 3 Above Normal Precipitation (A) Precip N 2 2 3 with 60% Confidence on both A 3 4 5 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Section III: Utilization of PRED Output Once the sample of weather scenarios has been selected for each location, it is simply a matter of appending them, one at a time to observed weather to date, and running the crop model. The results are 25 (or whatever number was selected) end-of-season percent of maximum-yield-remaining estimates for each location. PRED averages crop yields over all scenarios to give a best estimate of the final yield at that location. The average yield is given along with ?ne standard deviation above and below the average (68% confidence Applications and Limitations PRED significantly enhances the capacity of UPSTREET-type analysis by developing in a rational and objective way, predictive weather which can be used to drive the UPSTREET crop model. PRED is not restricted in use to the USSR; it can be used in any country for which historical weather data is available. In addition, it also has potential for use with CROPCAST, a generic version of the UPSTREET crop model, also used primarily for grain estimates; with regression-type models designed for the assessment of grains and non-grains; and with the Ritchie generic crop growth model which can be employed to forecast yields of a wide variety of crops. F__] PRED also can be used to assess the effect of weather on crops in any given season. In this operational mode the user inputs a forecast of average temperature and precipitation for the entire growing season. The resulting yield values. can be compared with yield values obtained by running the crop model on actual weather for the full growing season. Furthermore, PRED has the potential to project the range of grain yields within established time frames by forecasting extremes in weather, i.e., in seasons that are excessively dry or very cool. It does not have the capacity to forecast short-term weather conditions, however, and it can neither anticipate such phenomena nor accept forecasts of the likelihood of their occurrence. Finally, PRED is structurally limited to 40 stations or locations per run, but multiple runs can be made. In an area as large as the USSR, it will therefore be most useful when applied to key indicative areas. 5 See the appendix for examples of output. 25X1 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 I I Appendix 1 This appendix describes the functions and interrelationships of files and programs that collectively canprise the PRED model. It will be most valuable when used in conjunction with the diagram of the entire PRED model (see figure 1). Sections I, II and III are divided by dotted lines on the figure. The crop model and random number generator module shown on the figure are exterior routines. Appendix 2 describes the files and their required Section I of PRED compiles historical weather data and arranges it for use in developing weather scenarios. It contains a total of six files (the Historic Data Base file; the Historic Monthly file; the Monthly Check file; the Station Statistics file; the Scenario file; and the Scenario Attributes file) and three programs (MONFILE 2, CLIMSTAT, and SCENARIO). Section II of PRED selects predictive weather for input to the crop model. Within this Section there are three files (the Forecast Input file; the PREDMET file; and the PREDMET Output file) and one program (PREDMET). Section III identifies the locations in the crop model that correspond to the PRED stations, and provides PRED weather to the crop model so that it can compute final yields. This Section contains a total of six files (the PRED Cell List; the Yield Strip file; the Last Day Model file; the Last Day Strip file; the Last Day PRED file; and the LOSS file) and the PREDSTRPR (PRED Stripper) and LOSS programs. This file is canprised of daily weather records of maximum and minimum temperatures (in degrees C), precipitation amounts (in millimeters) and evapotranspiration (ETP) rates (in millimeters) for a maximum of 3,000 locations. Stations for which less than eight years of data are available are not included. The data, arranged chronologically, are derived fran reports generated by stations participating in the World Meteorological Organization (WM10) reporting program; they are quality controlled and reformatted for agricultural applications by the US Air Force Environmental Technical Applications Center. The data base includes information on the USSR dating from 1968. Historical Data Base Variable Description Station Number Year Julian Day ETP (MM) Precipitation (mm) Maximum Temperature (C) Minimum Temperature (C) I4onfile 2 Program The MONFILE 2 program reads the Historical Data Base file, groups and Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Figure 1 PRED Flow Diagram Historic Data Base Station Statistics File RANDOM M RINAE Predmet Input File PRED Cell List Yield Strip File MON W 2 CLIMSTA' REDI5IET PREDSTRPR Historic Monthly File Monthly Check Data File Scenario File ~7 Scenario Attributes File t ff et 1 Strip File Last Day ----- I I CROP MODEL Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Last Day Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 I I reformats the information into monthly increments, and stores the results in the Historic Monthly file. Historic Monthly File The Historic Monthly file is the repository of data reformatted by the t4)NFILE 2 program. In this file the data for each location are grouped into monthly records, which became input to the CLIMSTAT program. Monthly Check Data File The Monthly Check Data file is built by the user and contains information used to control operation of the CLIMSTAT program. The information includes: the station number, the total number of months of weather data in the station's data base, and a processing flag which indicates if the station is to be processed. CLIMSTAT.Program The CLIMSTAT program reads the Monthly Check Data file to establish, for each half-month in the year, precipitation, temperature, and evapotranspiration parameters for each station. The probability of precipitation for a certain day is defined by a first order Markov chain which expresses the probability of precipitation as a function of whether or not precipitation occurred on the previous day. The values of temperature and ETP are assumed to follow normal distributions that are defined by a mean and standard deviation computed from historical data. The amount of precipitation is assumed to follow an Incomplete Gamma distribution defined by two parameters--gamma and beta. For maximum and minimum temperatures and ETP, distributions are defined for. each half-month; for precipitation amount, the resolution is at the whole month level. This file receives and stores the output of the CLIMSTAT program, in which one set of statistics per station is produced. Each set of statistics contains climatological parameters for each station, and these parameters (a total of 16) are organized by half-month increments. Station Statistics File Parameters Precipitation Probabilities for the Next Day: 1. Probability when previous day had precipitation. 2. Probability when previous day had no precipitation. For a Precipitation Day: 3. Maximum temperature - mean 4. Maximum temperature - standard deviation 5. Minimum temperature - mean 6. Minimum temperature - standard deviation 7. ETP - mean Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 8. ETP - standard deviation 9. Gamma -- (Used to define the Incomplete Gamma Function 10. Beta -- that describes the amount of precipitation). For a Dry Day: 11. Maximum temperature - mean 12. Maximum temperature - standard deviation 13. Minimum temperature - mean 14. Minimum temperature - standard deviation 15. ETP - mean 16. ETP - standard deviation Scenario Program The Scenario program uses data in the Station Statistics file, in conjunction with a random number generator, to build 200 season-long weather scenarios for each station. Random numbers are used to translate the parameters from CLIMSTAT into weather outcomes for each day. The program also builds the Scenario Attributes file, which contains the day-today accumulations of temperature and precipitation for each scenario. The Scenario file is created by the SCENARIO program and is the repository of the 200 season-long weather scenarios produced by the latter. This very large file is used by the PREDMET program. To save space the . records contain no information on stations or date; hence PRED software must be provided with accurate information or, the sequence of stations as well as the start and end dates of the scenarios. The user must keep separate records on the order of data in this file. The Scenario Attributes file contains accumulations of temperature and precipitation for each scenario in the Scenario file. The records in this file are used by the PREEMET program to evaluate relative warmth and wetness of the developed scenarios in the scenario selection process. In addition, the Scenario Attributes file allows the user to make comparisons of any . portion of a scenario with a like portion of any other scenario. Forecast Input File The Forecast Input file is created by the user and contains weather forecasts for each station for specified time periods. The forecasts indicate whether temperature and precipitation will be below average, average, or above average. Forecasts can be given for a maximum of 11 time intervals. A confidence level is also established for each forecast. This file contains a temperature forecast code, atemperature confidence level, a precipitation forecast code and a precipitation confidence level for each of the 11 forecast intervals. 25X1 25X1 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Forecast Input File Description 3-Month Forecast - 3 Locations Location Month 1 1 1 2 1 3 2 1 2 2 2 3 3 1 3 2 3 3 A = Above Normal N = Normal B = Below Normal Temperature Precipitation Forecast-Confidence Forecast-Confidence A 90% N 80% N 70% N 70% N 60% N 60% B 80% A 80% B 70% N 70% N 60% N 60% N 90% A 90% N 70% N 70% N 70% A 70% PREDMET Input File The PREDMET Input file is created to control the operation of the PREDMET run. These controls establish starting and stopping dates for each run, state the number of iterations to be included in the run, define the forecast intervals to be employed, and list the stations that are to be assessed. The file is updated by the user as needed. The Random Module uses random numbers fran 0.0 to 1.0 as probabilities to determine whether or not precipitation occurs, the amount of that ,precipitation, maximum and minimum temperatures, and ETP for each day in building a year-long scenario. It is also used in selecting the subset of scenarios by the PREEMET program. PREDMET Program The PREE1ET program uses the Forecast Input file, PRE71DET Input file, Scenario file, Scenario Attributes file, and the Random Module to control the selection of scenarios covering the period that extends fran a selected date to the end of the growing season or other selected stopping date. The 25 scenarios thus selected for each location will be biased toward the forecast but with a statistically meaningful sample spanning a broader range of conditions. Program output is stored in the PREEMET Output file and serves as the meteorological input for the crop model. PREEf1ET Output File The PREEMET Output file is structured exactly like the meteorological data input file (MET) used by the crop assessment model. Information in it can thus be used by the crop model without change. This file contains the daily meteorological data of the 25 scenarios selected for each location. Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Each record in this file contains a day's worth of meteorological information for a single location and one of the 25 iterations. Last Day Model File This file is created by the crop model, using actual weather up to the day PRED is run. PRED uses this file to generate the Last Day Strip file and, via the crop model, the Last Day PRED file. The PRED Cell List is a control file that matches the selected locations in PRED with locations in the crop model.6 PREDSTRPR Program The PREDSTRPR program (PRED Stripper) reads the output of the Last Day rbdel file and selects records that pertain to the locations specified in the PRED Cell List. It creates the Last Day Strip file, which inputs to the crop model, and the Yield Strip file, which inputs directly to the LOSS program. F Last Day Strip File The Last Day Strip file, generated by PREDSTRPR, is. identical to the Last Day Model file except that it also contains an iteration number that corresponds to the weather scenario being processed. It is input to the crop Yield Strip File This file contains the estimated percent of yield remaining, as of the beginning day on which the crop model is run on PRED data, at each crop model location. Last Day PRED File The Last Day PRED file is the output Last Day file derived fran running the crop model or. PRED data. It contains end-of-season values, expressed in yield percent, for each location and each weather scenario. This is input to the LOSS program. LOSS Program The LOSS program canputes the mean and standard deviation of the results of the Last Day PRED file. Wien weather data are not available for all locations in a region, the results of the Last Day PRED file are used in conjunction with the Yield Strip file to determine the mean incremental change in yield and its standard deviation. These results are assigned to locations using a nearest neighbor assignment scheme. This output forms the LOSS 6 The crop model runs on a gridded cell format. Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 file. The LOSS file is the output mean and standard deviation for all locations in the LOSS program. Figure 2 demonstrates these results for one location. Tb illustrate, this average end-of-season crop yield for spring wheat is given to be 54.1% of the historical maximum yield for location 1. Some gather scenarios deteunined crop yields that were less than this, sane more, as indicated by the spread in the distribution. The actual standard deviation (SD) was calculated to be 6.2, so that a 95% confidence interval about 54.1% would be 54.1% +,12.4% (i.e., + 2 standard deviations). The interval 41.7% to 66.5% will contain the true or actual yield 95% of the time. Table 2 contains a sample output for 30 locations. Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Figure 2 Distribution of Crop Yield as a Percent of Maximum for Location 1 Percent of Maximum Yield Remaining Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-R DP85T00287R000600580001-4 25X1 I I Location Estimated Crop Yield As A Percentage of Thtal With One Standard Deviation Limit Spring Vheat 47.9 54.1 60.3 59.8 66.3 72.8 54.4 58.7 63.0 43.6 50.0 56.4 52.6 56.3 60.0 66.8 70.7 74.6 63.3 68.8 74.3 45.3 48.8 52.3 57.0 61.8 66.6 55.2 60.4 65.6 64.0 67.5 71.0 53.5 58.7 63.9 .66.9 72.3 77.7 44.7 47.2 49.7 69.8 73.0 76.2 68.9 73.5 78.1 72.1 76.1 80.1 69.1 73.8 78.5 63.9 67.3 70.7 62.4 66.2 70.0 81.1 84.5 87.9 50.6 54.0 57.4 55.6 57.9 60.2 61.0 65.0 69.0 81.8 85.3 88.8 73.1 76.9 80.7 78.3 81.5 84.7 73.4 78.3 83.2 68.5 74.1 79.7 69.3 73.4 77.5 25X1 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4 I I Appendix 2 Description Files Created By Used By Medium Storage (Bytes) Historic Data Base External MONFILE2 Tape 8000/location/year Historic Monthly MJNFILE2 CLIMSTAT Tape 6000/location/year Monthly Check Data User CLIMSTAT Disk 14/location Station Statistics CLIMSTAT SCENARIO Tape or Disk 1536/location Scenario SCENARIO PREDMET Tape 600,000/location Scenario Attributes SCENARIO PRELIU11ET Tape 300,000/location Predmet Input User PREDMET Disk 1000 Forecast Input User PREDMET Disk 200/location Predmet Output PREDMET Crop Model Tape or Disk 28/location/iteration/day Pred Cell List user PREDSTRPR Disk 7/location Yield Strip PREDSTRPR LOSS Disk 32/location Last Day Strip PREDSTRPR Crop Model Disk 264/location/iteration Last Day Pred PREDI OD LOSS Disk or Tape 264/location/iteration Last Day Model Crop Model PREDSTRPR/LOSS Tape 264/crop model locations LOSS External Disk or Tape 92/crop model locations Notes: number of locations : 20-40 number of years : 10-15 number of iterations: 25-50 number of days : 30-300 25X1 13 Sanitized Copy Approved for Release 2011/07/19: CIA-RDP85T00287R000600580001-4