The NASA Water Vapor Project (NVAP) dataset is an existing earth system data record consisting of global blended total column and layered water vapor from a variety of sensors. This existing dataset provides gridded daily water vapor fields from 1988-2001, and has been used in a diverse assortment of climate, modeling, process, and weather studies. The heritage dataset was produced in several phases; however each phase merely extended the period of coverage and no reanalysis was ever performed on existing data.

A current project under the NASA Making Earth Science Data Records for Use in Research Environments (MEaSUREs) program has both reanalyzed this dataset and extended it to cover 1987-2010. The reanalyzed and extended dataset is referred to as NVAP-MEaSUREs (NVAP-M) and includes data inputs from the High Resolution Infrared Sounder (HIRS), Special Sensor Microwave Imager (SSM/I), Atmospheric Infrared Sounder (AIRS), water vapor from ground-based Global Positioning System (GPS) and radiosondes.

NVAP-M is a stable, climate-quality earth system data record (ESDR) that has removed several of the time dependent biases found in the heritage NVAP dataset by using consistent instrument inputs and algorithms through the entire dataset. NVAP-M is observation-based and has minimal influence from model outputs.

NVAP-M offers multiple data streams, each catering to a variety of user needs. NVAP-Climate stresses a constant mix of data through time at a small cost to spatial and temporal resolution. A similar product was produced covering only the global oceans (NVAP-Ocean). Meanwhile, the weather-oriented component (NVAP-Weather) uses a changing assortment of inputs to provide higher spatial and temporal coverage at the cost of long-term temporal stability.

The 24-year NVAP-M water vapor record is being made available to experienced potential users for preliminary investigation, and several examples of available products and preliminary results will be shown. The final dataset will be publicly available in the NASA Langley Atmospheric Science Data Center (ASDC) in the first quarter of 2012.