Project Title: Global Precipitation Variations and Extremes PI: R. Adler (UMD) Co-I’s: G. Huffman (SSAI/GSFC), G. Gu (UMD/GSFC), S.Curtis (ECU) Science issue: Determine how the characteristics of global precipitation are changing in terms of means, variations and extremes and integrate this info. into energy/water cycle studies Approach:Analyze the GPCP record along with other shorter, high quality data sets such as TRMM . Satellite-based data: GPCP, TRMM radar and passive estimates, SSM/I, AMSR, TRMM Multi- satellite Precipitation Analysis (TMPA) 3-hr data Other data and models:Other water cycle/ reanalysis data sets Study Period:1979-present for long-term studies; 1998-present (TRMM period) for focused comparisons and extremes Progress toward Implementation Plan: • Determination of climatological rain and bias error using multiple products for water cycle closure. Estimate of bias error for global precipitation is =.25 mm/d ; /= 9.5% . • New GPCP V2.1 released: Main changes over land due to new gauge analysis. Global mean now 2.68 mm/d (+2% globally; +6% over land from V2). Trend pattern similar, tropical ocean positive trend reduced . Should improve land water balances. • Rainfall comparison with MERRA initiated. Means, inter-annual New GPCP V2.1 Means and Trends GPCP ‘98-’07 Mean () Std.Dev. () of products # of input products / mm/d mm/day/ decade mm/day GPCP V2.1 Mean (1979- 2007) GPCP V2.1 Trend (1979- 2007) Adler, R.F., G. Gu, J.-J. Wang, G.J. Huffman, S. Curtis and D. Bolvin, 2008: Relationships between Global Precipitation and Surface Temperature on Inter-annual and Longer Time Scales (1979-2006). J. Geophys. Res., 113, D22104, doi:10.1029/2008JD010536. Huffman, G. J., R. F. Adler, D. T. Bolvin, and G. Gu (2009), Improving the global precipitation record: GPCP Version 2.1, Geophys. Res. Lett., 36, L17808, doi:10.1029/2009GL040000. variations, daily distributions, extremes, temp./rain relations. Early results indicate recent ocean means a little high over tropics, a little low in mid- latitudes , generally better than other re- analyses. ENSO pattern and magnitudes good , but trends

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Project Title : Global Precipitation Variations and Extremes PI: R. Adler (UMD) Co-I’s: G. Huffman (SSAI/GSFC), G. Gu (UMD/GSFC), S.Curtis (ECU). GPCP ‘98-’07 Mean ( ). Std.Dev. ( ) of products. mm/d. # of input products. /. New GPCP V2.1 Means and Trends. - PowerPoint PPT Presentation

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Page 1: Project Title : Global Precipitation Variations and Extremes

Project Title: Global Precipitation Variations and ExtremesPI: R. Adler (UMD) Co-I’s: G. Huffman (SSAI/GSFC), G. Gu (UMD/GSFC), S.Curtis (ECU)

Science issue: Determine how the characteristics of global precipitation are changing in terms of means, variations and extremes and integrate this info. into energy/water cycle studiesApproach:Analyze the GPCP record along with other shorter, high quality data sets such as TRMM. Satellite-based data: GPCP, TRMM radar and passive estimates, SSM/I, AMSR, TRMM Multi-satellite Precipitation Analysis (TMPA) 3-hr data Other data and models:Other water cycle/ reanalysis data sets Study Period:1979-present for long-term studies; 1998-present (TRMM period) for focused comparisons and extremes

Progress toward Implementation Plan:

• Determination of climatological rain and bias error using multiple products for water cycle closure. Estimate of bias error for global precipitation is =.25 mm/d; /= 9.5%.

• New GPCP V2.1 released: Main changes over land due to new gauge analysis. Global mean now 2.68 mm/d (+2% globally; +6% over land from V2). Trend pattern similar, tropical ocean positive trend reduced. Should improve land water balances.

• Rainfall comparison with MERRA initiated. Means, inter-annual

New GPCP V2.1 Means and Trends

GPCP ‘98-’07 Mean ()

Std.Dev. () of products

# of input products /

mm/d

mm/day/decade

mm/day

GPCP V2.1 Mean (1979-2007)

GPCP V2.1 Trend (1979-2007)Adler, R.F., G. Gu, J.-J. Wang, G.J. Huffman, S. Curtis and D. Bolvin, 2008: Relationships between Global Precipitation and Surface Temperature on Inter-annual and Longer Time Scales (1979-2006). J. Geophys. Res., 113, D22104, doi:10.1029/2008JD010536.

Huffman, G. J., R. F. Adler, D. T. Bolvin, and G. Gu (2009), Improving the global precipitation record: GPCP Version 2.1, Geophys. Res. Lett., 36, L17808, doi:10.1029/2009GL040000.

variations, daily distributions, extremes, temp./rain relations. Early results indicate recent ocean means a little high over tropics, a little low in mid-latitudes, generally better than other re-analyses. ENSO pattern and magnitudes good, but trends problematic.