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CHG rainfall products

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

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CHG rainfall products

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  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. Objectives: Results: CHIRP (1981 - present) and FTIP (2000 - 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. Objectives: Results: CHIRP (1981 - present) and FTIP (2000 - present) Global unbiased 0.05 degree pentads available with 2 day lag tinyurl.com/chg-products Improved Results: CHIRP/FTIP blended with station data, 1 pentad lag

  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 (2000 - present) and B1 IR data (1981 - 2008) • CHIRP (1981-present) = FCLIM * (IRP %normal) • Use TRMM-RT7 data (2000 - present) • FTIP (2000-present) = FCLIM * (IRP %normal + TRMM-RT7 %normal)/2 • SPACE TIME

  5. CHIRP 2012.09.6 0.05º, global, unbiased, rainfall pentad [mm] with 2 day lag.

  6. FTIP 2012.09.6 0.05º, 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 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] • for each data set to validate, CHIRP, FTIP, TRMM, ECMWF… • build cubes of 2 month totals based on growing season. time series time series FTIP ‘True’ latitude latitude longitude longitude correlation bias ratio mean absolute error misses

  9. TRMM-RT7 ECMWF Correlation with interpolated stations CHIRP FTIP -0.5 0.0 0.5 0.7 1.0

  10. TRMM-RT7 ECMWF Bias ratio to interpolated stations CHIRP FTIP 0.0 0.5 0.8 1.2 1.5 >1.5

  11. TRMM-RT7 ECMWF Mean Absolute Error with interpolated stations CHIRP FTIP 0 40 60 100 >100

  12. TRMM-RT7 ECMWF Misses compared to interpolated stations CHIRP FTIP 0 1 4 9 >9

  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, 0.05º, 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 CHG Stations database FCLIMS, 1920 present, 5Km, 5days FCLIM FTIPS 2005-prst, 5Km, 5days FTIP CHIRPS 1980-present, 5Km, 5days CHIRP IRP 2000-prnt Join 80-prst BIRP 1980-2008 CCD model

  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 CHIRP clim 09.6 pentad, pixel, = 2176 points/year p-3 p-2 p-1 p p+1 p+2 p+3

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

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

  27. CMORPH ECMWF Validation - Correlations red TRMM-RT7 FTIP-RT7 -1.0 0.0 0.5 0.7 1.0

  28. PERSIANN TRMM-V6 Validation - Correlations 2 red TRMM-V7 CHIRP-V7 -1.0 0.0 0.5 0.7 1.0

  29. PERSIANN TRMM-V6 Validation - Correlations 2 blue TRMM-V7 CHIRP-V7 -1.0 0.0 0.5 0.7 1.0

  30. PERSIANN TRMM-V6 Validation - Mean Absolute Error 2 TRMM-V7 CHIRP-V7 0 40 60 100 >100

  31. PERSIANN TRMM-V6 Validation - Bias ratio 2 TRMM-V7 CHIRP-V7 0.0 0.5 0.8 1.2 1.5 >1.5

  32. PERSIANN TRMM-V6 Validation - Misses 2 TRMM-V7 CHIRP-V7 0 1 4 9 >9

  33. TRMM-RT7 ECMWF Correlation with interpolated stations CHIRP FTIP -1.0 0.0 0.5 0.7 1.0

  34. TRMM-RT7 ECMWF Bias ratio to interpolated stations CHIRP FTIP 0.0 0.5 0.8 1.2 1.5 >1.5

  35. TRMM-RT7 ECMWF Mean Absolute Error with interpolated stations CHIRP FTIP 0 40 60 100 >100

  36. TRMM-RT7 ECMWF Misses compared to interpolated stations CHIRP FTIP 0 1 4 9 >9

  37. B1 fails

  38. B1 fails 4

  39. 0.05º, global, unbiased, rainfall pentad [mm] with 2 day lag. CHIRP 2012.09.5

  40. 0.05º, global, unbiased, rainfall pentad [mm] with 2 day lag. FTIP 2012.09.5

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