The latest GPCP Daily and Monthly Products: Current Status, Assessments, and the Future Plans

The Global Precipitation Climatology Project (GPCP) is a popular combined satellite-gauge precipitation dataset in which the long-term CDR standards of consistency and homogeneity are emphasized. This presentation is composed of four major parts: (1) a brief overview of the latest GPCP Daily and Monthly products (V3.2) and satellite-gauge input data sets used in them; (2) comparison of the GPCP V3.2 products with the previous version of GPCP Daily (V1.3) and Monthly (V2.3) products and highlighting major changes; (3) assessment of the GPCP V3.2 products over the oceans using Passive Aquatic Listeners (PALs), over sea ice using snow depth data from a combination of ICESat-2 and Cryosat-2 observations plus ERA5 estimates, and over Antarctica using CloudSat; (4) insights from the latest GPM (V07) products as they are related to GPCP and the update of GPCP to GPCP V3.3. Several major changes occurred in GPCP V3.2, including: (1) moving from Monthly 2.5°x2.5° and Daily 1.0°x 1.0° spatial resolution in V2.3 to 0.5°x0.5° for both Monthly and Daily products; (2) calibrations to climatologies based on high-accuracy satellite missions, including TRMM, CloudSat, GPM, and GRACE; and (3) use of new precipitation retrieval and calibration methods. Compared to V2.3, GPCP V3.2 shows about a 6.5% increase in global oceanic and about a 4.5% increase in global (land and ocean) precipitation rates with some major changes over the ocean between 40^°S and 60^°S. Similar to V2.3, near-zero global precipitation trend is observed in V3.2.  However, regional trends, which are substantial, remain generally similar between V2.3 and V3.2. Evaluations over the oceans using PALs showed that GPCP V3.2 substantially outperforms GPCP V2.3 in representing rain occurrence and rain intensity at daily scale, likely due to the use of IMERG in the GPCP V3.2 Daily product. Our study suggests that GPCP V3.2 generally captures the snowfall accumulation pattern over sea ice, compared to that obtained from the combined ICESat-2 and Cryosat-2 observations, as well as that from ERA5. However, this set of products shows considerable differences in the amount of snowfall accumulation, with ERA5 often showing the highest values. We will end the presentation by briefly discussing our plans for further improvement of GPCP, including higher spatial and temporal resolution, lower latency, and the use of more-advanced gauge analysis and precipitation retrieval methods.