ESDS Program

Improvement of the NVAP Global Water Vapor Data Set for Climate, Hydrological and Weather Studies

Principal Investigator (PI): Thomas Vonder Haar, Science and Technology Corp.

This proposal utilizes the Aqua retrievals of total column and layered precipitable water to extend the global water vapor data record, and to improve and refine NASA's historical Water Vapor Project (NVAP) global products.

From 1992 to 2003 in three separate efforts, the principal investigator and his team at Science and Technology Corporation (STC)-Meteorological Satellite (METSAT) have developed this unique 14-year climate data set (1988-2001) for NASA's Earth System Science Pathfinder. The existing NVAP dataset has been cited in over 150 scientific papers, but a reanalysis is needed to make the dataset consistent for detection and understanding of long-term trends which are hypothesized to occur as Earth warms.

By continuing to expand the temporal coverage of water vapor measurements from satellites and improving the analysis, we create a record of variability of Earth's water vapor on various scales. The use of Aqua water vapor retrievals will greatly improve the error characteristics of the historical NVAP data, and also allow for much improved studies on long-term variability and climate trends. Key features of this dataset for researchers are the daily, vertical-layer water vapor fields over BOTH land and ocean.

This enables advanced climate and weather research as well as studies of interest to hydrologists. In our approach, years 2003 and 2004 will be "bridge" years, where the heritage NVAP approach will be compared to the powerful Aqua measurements from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and Atmospheric Infrared Sounder (AIRS).

This will extend the influence of the Aqua instruments back in time by comparing the pre-Aqua data set approach to the Aqua record. The final result will be a 24-year global water vapor dataset spanning 1987 - 2010 called NVAP-Making Earth System Data Records for Use in Research Environments (MEaSUREs), or NVAP-M.

The proposed effort will support the research aims of the new Intergovernmental Panel on Climate Change First Assessment Report (FAR) and will lay the groundwork for additional Suomi National Polar-orbiting Partnership (Suomi NPP) and NPOESS contributions to the global water vapor record.

Visit the NVAP-M dataset

Distributed by NASA's Atmospheric Science Data Center (ASDC)

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