Next-Generation Global Precipitation Climatology Project (GPCP) Data Products
The suite of current Global Precipitation Climatology Project (GPCP) precipitation products (Version 2) based on global observational data has become a science community standard, having been used in over 2500 journal articles. The current monthly (1979-present), pentad (1979-present), and daily products (1997-present) have been developed by research groups over the last 15 years and are produced by a consortium of those groups, supported and sometimes funded by various agencies. The GPCP is the precipitation component of an internationally coordinated set of (mainly) satellite-based global products dealing with the Earth s water and energy cycles, under the auspices of the Global Water and Energy Experiment (GEWEX) Data and Assessment Panel (GDAP) of the World Climate Research Program (WCRP). The GDAP (Chair: C. Kummerow) is coordinating the development and production of the next generation of products covering the water and energy cycles to enhance the community s ability to analyze the Earth s climate processes for the satellite era (~30 years).
We propose to produce the next generation (Version 3) of GPCP merged precipitation products, which will involve a significant shift to new data streams, modern Level 2 algorithms, advanced merger techniques, and finer time and space resolutions. We will complete the development of the techniques, implement the techniques to merge the relevant data sets into a consistent, globally complete observationally based precipitation analysis at various time scales from monthly to 3-hourly, and provide quality control, validation, and uncertainty estimation for the products. In parallel, precipitation estimates from numerical reanalyses will be merged with the observations to provide additional joint observation-model products with improved quality where model use is acceptable. Throughout, the CDR standards of consistency and homogeneity will be emphasized. The final result will be on-going production of an improved suite of inter-consistent products over the time span 1979-present with resolutions matching the other GEWEX-related water/energy cycle products. Specifically, the products will cover the period 1979-present at the monthly and pentad (10-day) time scales, the period 1982-present for daily, and the period 1998-present for 3-hourly. One important difference from other data sets is that all these products will be inter-consistent for all overlapping time spans.
Leveraging NASA-funded products and research is a key part of the work. The analyses will utilize a number of NASA and NASA-supported data sets, algorithms and products, including those based on Special Sensor Microwave Imager (SSMI) and Special Sensor Microwave Imager/Sounder (SSMIS) (using the Goddard Profiling Algorithm [GPROF]), Atmospheric Infrared Sounder (AIRS), Tropical Rainfall Measuring Mission (TRMM), and the forthcoming Global Precipitation Measurement (GPM). This proposal will also be linked to the current Making Earth System Data Records for Use in Research Environments (MEaSUREs) effort to provide error estimates for precipitation products at monthly to 3-hr time scales (see "Next-Generation Global Precipitation Climatology Project (GPCP) Data Products"), so that the new GPCP Version 3 products will have attached bias and random error estimates.
We expect these data sets to provide key input to the climate community in the broad sense, namely users who require long, global records of precipitation that emphasize CDR characteristics ahead of instantaneous precision. The various time resolutions are intended to support modern requirements for distributions of precipitation rate at a variety of time scales. This consistent set of products over a range of time resolutions will allow the critical study of climate-scale fluctuations and their connection to weather-scale variations and extremes.
George Huffman - PI, Science Systems and Applications, Incorporated
Last Updated: Nov 15, 2017 at 12:49 PM EST