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CHG rainfall products Make best possible rainfall products for monitoring crop stress in areas of rain fed agriculture. Objectives:

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Presentation on theme: "CHG rainfall products Make best possible rainfall products for monitoring crop stress in areas of rain fed agriculture. Objectives:"— Presentation transcript:

1 CHG rainfall products Make best possible rainfall products for monitoring crop stress in areas of rain fed agriculture. Objectives:

2 CHG rainfall products Make best possible rainfall products for monitoring crop stress in areas of rain fed agriculture. Results: Objectives: CHIRP ( present) and FTIP ( present) Global unbiased 0.05 degree pentads available with 2 day lag tinyurl.com/chg-products

3 CHG rainfall products Make best possible rainfall products for monitoring crop stress in areas of rain fed agriculture. Improved Results: Objectives: CHIRP/FTIP blended with station data, 1 pentad lag Results: CHIRP ( present) and FTIP ( present) Global unbiased 0.05 degree pentads available with 2 day lag tinyurl.com/chg-products

4 Quick overview of how we get there… Start with long term monthly average rainfall maps FCLIM Aside: build monthly models of rainfall trained on TRMM-V7 –derive coefficients a and b, such that rain rate = a * CCD + b (IRP) –where CCD is the percentage of observation where IR temp < threshold Calculate IRP pentads from CPC IR data ( present) and B1 IR data ( ) CHIRP (1981-present) = FCLIM * (IRP %normal) Use TRMM-RT7 data ( present) FTIP (2000-present) = FCLIM * (IRP %normal + TRMM-RT7 %normal)/2 SPACE TIME

5 CHIRP º, global, unbiased, rainfall pentad [mm] with 2 day lag.

6 FTIP º, global, unbiased, rainfall pentad [mm] with 2 day lag.

7 FCLIM derived wet season JFM FMA MAM AMJ MJJ JJA JAS ASO SON OND NDJ DJF

8 Validation analysis for each data set to validate, CHIRP, FTIP, TRMM, ECMWF… build cubes of 2 month totals based on growing season. Season time series (2001 – 2011) JFM [J1+F1, J1+M1, F1+M1, …, J11+F11, J11+M11, F11+M11]... JAS [J1+A1, J1+S1, A1+S1, …, J11+A11, J11+S11, A11+S11]... NDJ [N1+D1, N1+J2, D1+J2, …, N11+D11, N11+nan, D11+nan] longitude latitude time series longitude latitude time series ‘True’ FTIP correlation bias ratio mean absolute error misses

9 Correlation with interpolated stations TRMM-RT7 ECMWF CHIRP FTIP

10 Bias ratio to interpolated stations >1.5 TRMM-RT7 ECMWF CHIRP FTIP

11 Mean Absolute Error with interpolated stations >100 TRMM-RT7 ECMWF CHIRP FTIP

12 Misses compared to interpolated stations >9 TRMM-RT7 ECMWF CHIRP FTIP

13 CHG Station Climate Database Daily rainfall observations from many public and private sources going back to the 1800’s Currently ~950,000 records in db Used to create spatially interpolated fields Challenge identifying duplicates, non-zero zeroes Constantly topping off db from available sources Blended into satellite rainfall products

14 January 2009 Original

15 January 2009 Fixed

16 B1 fails 2

17 B1 fails 3

18 Summary 2 rainfall products, CHIRP (1981-present) & FTIP (2000-present) Global, 0.05 º, unbiased, pentads with 2 day lag. Compare very well with existing rainfall products. Developing an extensive station rainfall database Used to blend station data with CHIRP and FTIP

19 Thank You … Chris Funk Greg Husak Joel Michaelsen Diego Pedreros Andrew Verdin Marty Landsfeld Boleslo Romero FEWS NET Data available via anonymous ftp: tinyurl.com/chg-products

20 CHG Rainfall Product Paths FCLIM CHG Stations database FTIPS 2005-prst, 5Km, 5days CCD model IRP prnt BIRP Join 80-prst CHIRP CHIRPS 1980-present, 5Km, 5days FTIP FCLIMS, 1920 present, 5Km, 5days Source Datasets Station Average monthly rainfall Rainfall predictors TRMM7-RT 2000-prsnt IR-B CPC-IR – 2000-prsnt TRMMV present

21 Some data issues. B1 glitches Station zeroes not zero

22 IDW weights for nearest 3 neighbors mapped to red, green, blue

23 Geostarionary coverage

24 How to make FAT clims pentad, pixel, p-3 p-2 p-1 p p+1 p+2 p+3 = 2176 points/year CHIRP clim 09.6

25 FCLIM derived wet season JFM FMA MAM AMJ MJJ JJA JAS ASO SON OND NDJ DJF

26 Validation - Africa correlations CMORPH CPC-Unified PERSIANN TRMM-V6 TRMM-V7 TRMM-RT7 CHIRP FTIP-V7 FTIP-RT7

27 Validation - Correlations red CMORPH ECMWF TRMM-RT7 FTIP-RT

28 Validation - Correlations 2 red PERSIANN TRMM-V6 TRMM-V7 CHIRP-V7

29 Validation - Correlations 2 blue PERSIANN TRMM-V6 TRMM-V7 CHIRP-V

30 Validation - Mean Absolute Error >100 PERSIANN TRMM-V6 TRMM-V7 CHIRP-V7

31 Validation - Bias ratio >1.5 PERSIANN TRMM-V6 TRMM-V7 CHIRP-V7

32 Validation - Misses 2 PERSIANN TRMM-V6 TRMM-V7 CHIRP-V >9

33 Correlation with interpolated stations TRMM-RT7 ECMWF CHIRP FTIP

34 Bias ratio to interpolated stations >1.5 TRMM-RT7 ECMWF CHIRP FTIP

35 Mean Absolute Error with interpolated stations >100 TRMM-RT7 ECMWF CHIRP FTIP

36 Misses compared to interpolated stations >9 TRMM-RT7 ECMWF CHIRP FTIP

37 B1 fails

38 B1 fails 4

39 CHIRP º, global, unbiased, rainfall pentad [mm] with 2 day lag.

40 FTIP º, global, unbiased, rainfall pentad [mm] with 2 day lag.


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