Improving the global precipitation record: GPCP Version 2.1

Authors

  • George J. Huffman,

    1. Global Precipitation Climatology Project, Laboratory for Atmospheres, Global Merge Development Centre, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
    2. Science Systems and Applications, Inc., Lanham, Maryland, USA
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  • Robert F. Adler,

    1. Global Precipitation Climatology Project, Laboratory for Atmospheres, Global Merge Development Centre, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
    2. Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, USA
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  • David T. Bolvin,

    1. Global Precipitation Climatology Project, Laboratory for Atmospheres, Global Merge Development Centre, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
    2. Science Systems and Applications, Inc., Lanham, Maryland, USA
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  • Guojun Gu

    1. Global Precipitation Climatology Project, Laboratory for Atmospheres, Global Merge Development Centre, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
    2. Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, USA
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Abstract

[1] The GPCP has developed Version 2.1 of its long-term (1979–present) global Satellite-Gauge (SG) data sets to take advantage of the improved GPCC gauge analysis, which is one key input. As well, the OPI estimates used in the pre-SSM/I era have been rescaled to 20 years of the SSM/I-era SG. The monthly, pentad, and daily GPCP products have been entirely reprocessed, continuing to require that the submonthly estimates sum to the monthly. Version 2.1 is close to Version 2, with the global ocean, land, and total values about 0%, 6%, and 2% higher, respectively. The revised long-term global precipitation rate is 2.68 mm/d. The corresponding tropical (25°N-S) increases are 0%, 7%, and 3%. Long-term linear changes in the data tend to be smaller in Version 2.1, but the statistics are sensitive to the threshold for land/ocean separation and use of the pre-SSM/I part of the record.

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