Overview

This document mainly provides an overview of the precipitation data from the Global Precipitation Climatology Project, version 2.3 (GPCP V2.3). The data provided is of monthly frequency and is considered a Climate Data Record. Monthly mean data comes with uncertainty estimates. The data are archived at the NOAA National Centers for Environmental Information (NCEI). The dataset is part of the Global Energy and Water Cycle Exchanges (GEWEX) effort under the World Climate Research Program (WCRP). A 1 Degree Daily (1DD) precipitation estimate from GPCP also exists.

With the recent release of version 3.1 (GPCP V3.1), some information is found in this document about it. Information about the new version was released (as of March 10, 2021) and can be found in the Algorithm Theoretical Basis Document. GPCP V3.1 products are at monthly resolution with daily and 3-hourly products to come next.

Provider’s contact information

GPCP is produced through a joint effort between the University of Maryland and NASA.

Dataset Point of Contact:

NOAA CDR Program
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
+1 (828) 271-4800
gpcp_contacts@noaa.gov

Additional information is available from U of Maryland at http://eagle1.umd.edu/GPCP_ICDR/.

Licensing and citation

For V2.3, cite as:

Adler, R.F., M.R.P. Sapiano, G.J. Huffman, J.-J. Wang, G. Gu, D. Bolvin, L. Chiu, U. Schneider, A. Becker, E. Nelkin, P. Xie, R. Ferraro, and D.-B. Shin, 2018: The Global Precipitation Climatology Project (GPCP) Monthly Analysis (New Version 2.3) and a Review of 2017 Global Precipitation. Atmosphere, 9, 138. https://doi.org/10.3390/atmos9040138

Variable name and units (for V2.3)

Spatial coverage and resolution

This dataset combines observations and satellite precipitation data into a 2.5°x2.5° global grid.

Monthly precipitation from GPCP V3.1 will be at 0.5°x0.5° spatial resolution.

Temporal coverage and resolution

Monthly precipitation values are provided through from 1979/01 through present, with recent months considered ‘interim’.

For V3.1, the monthly precipitation record will begin from January 1983.

Information about observations (number, homogeneity)

Satellite data over the land and ocean are combined with gauge analysis over land. Passive Microwave estimates are based on Special Sensor Microwave Imager/Special Sensor Microwave Imager Sounder (SSMI/SSMIS) data. Infrared precipitation estimates are included using Geostationary Operational Environmental Satellite (GOES) data and Polar-orbiting Operational Environmental Satellite (POES) data, as well as other low earth orbit data and in situ observations.

Primary sensors include:

• RSS SSMI T­b CDR from 1996-2008
• RSS SSMIS Tb CDR from 2009-present
• GPCP Monthly Analysis V2.3 from 1996-present
• TOVS precipitation from 1996-2002
• AIRS V6 precipitation from 2003-present (replaces TOVS)
• IR 3 hourly files, Tb from CPC from 1996-present

See Climate Algorithm Theoretical Basis Document for GPCP Monthly Analysis for sensor data timeline and details.

Methodology

The GPCP monthly precipitation dataset combines observations and satellite precipitation to populate a 2.5°x2.5° global grid. Gauge data comes from the Global Precipitation Climatology Center (GPCC) of the Deutscher Wetterdienst (DWD). Precipitation estimates come from polar-orbit passive microwave satellites (SSMI, SSMIS), polar orbit IR sounders (TOVS, AIRS), and geostationary infrared satellites (GOES, MeteoSat, GMS, MTSat).

Note a major update in V3.1: there is input from the Tropical Combined Climatology (TCC) and the Merged CloudSat, Tropical Rainfall Measuring Mission (TRMM), and Global Precipitation Climatology (GPM) Climatology (MCTG). The MCTG climatology is applied as a ratio to adjust the mid- and high-latitude precipitation values, which may improve the representation of precipitation in the Canadian North. Poleward of 65 N, the precipitation climatology is only based on CloudSat (it does not have a signal saturation issue).

Specific to higher latitudes (V2.3): Note that the polar orbit of the Special Sensor Microwave/Imager (SSM/I) and Special Sensor Microwave Imager/Sounder SSMIS give nominal coverage between 85° N-S but limitations in retrieval techniques prevent useful precipitation estimates over cold land (scattering), land (emission), or sea ice (both scattering and emission). From 70°N to North Pole, TOVS data are adjusted to the bias of the available monthly rain gauge data. From 60°-70°, there is a smooth transition with increased weighting of TOVS data relative to SSM/I with increasing latitude except where SSM/I observations are missing.

Information about the technical and scientific quality

While GPCP V2.3 has been used for global applications, it is somewhat limited in skill at high latitudes due to poor retrieval performance over icy or snowy surfaces, limited station measurements, or gaps requiring interpolation. Previous studies have used CloudSat climatology to adjust GPCP V2.3 values before performing analysis. For this reason, it may be preferable to use GPCP V3.1 when it becomes available, though it is not considered a Climate Data Record, so may have inhomogeneity (specifically in the TOVS/AIRS record)

Limitations and strengths for application in North Canada

V2.3 is not leveraging satellites and datasets which improve sampling over North Canada.

Different satellites are used at different latitudes, leading to spatial heterogeneity.

References to documents describing the methodology and/or the dataset

Adler, R.F., G.J. Huffman, A. Chang, R. Ferraro, P. Xie, J. Janowiak, B. Rudolf, U. Schneider, S. Curtis, D. Bolvin, A. Gruber, J. Susskind, and P. Arkin, 2003: The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979-Present). J. Hydrometeor., 4, 1147-1167.

Climate Algorithm Theoretical Basis Document for GPCP Monthly Analysis V2.3 (https://www.ncei.noaa.gov/data/global-precipitation-climatology-project-gpcp-monthly/doc/CDPR-ATBD-0848%20Rev%201%20Precipitation%20-%20GPCP%20Monthly%20C-ATBD%20(01B-34)%20(DSR-1083).pdf)

Climate Algorithm Theoretical Basis Document for GPCP Monthly Analysis V3.1 (https://docserver.gesdisc.eosdis.nasa.gov/public/project/MEaSUREs/GPCP/GPCP_ATBD_V3.1.pdf)

Source code is available for reference to maintain the transparency of the algorithm and processes. Found here (https://www1.ncdc.noaa.gov/pub/data/sds/cdr/CDRs/Precipitation_GPCP-Monthly/SourceCode_01B-34.tar.gz)

Link to download the data and format of data

NCEI Direct Download of Monthly V2.3 Data (https://www.ncei.noaa.gov/data/global-precipitation-climatology-project-gpcp-monthly/)

Download Monthly V3.1 data from the NASA GESDISC DATA ARCHIVE (https://measures.gesdisc.eosdis.nasa.gov/data/GPCP/GPCPMON.3.1/)

Data are in netCDF-4 file format.

Publications including dataset evaluation or comparison with other data in Canada

Hegyi, B. M., and Y. Deng, 2011: A dynamical fingerprint of tropical Pacific sea surface temperatures on the decadal-scale variability of cool-season Arctic precipitation. Journal of Geophysical Research, 116(D20). https://doi.org/10.1029/2011jd016001

Kusunoki, S., R. Mizuta, and M. Hosaka, 2015: Future changes in precipitation intensity over the Arctic projected by a global atmospheric model with a 60-km grid size. Polar Science, 9(3), 277–292. https://doi.org/10.1016/j.polar.2015.08.001

Song, Y., A. Behrangi, and E. Blanchard-Wrigglesworth, 2020: Assessment of satellite and reanalysis cold season snowfall estimates over Arctic sea ice. Geophysical Research Letters, 47, e2020GL088970. https://doi-org.myaccess.library.utoronto.ca/10.1029/2020GL088970.