Scatterometer data collected by polar orbiting satellites provide near real-time observations of wind speed and direction over open ocean. These data fills a void of in-situ wind observations over the open ocean waters, as well as over large seas and lakes. The NASA QuikSCAT satellite, launch in June 1999, generates 25km resolution wind vectors from the satellite's scatterometer known as SeaWinds. Data from SeaWinds has been available to the operational community since January 2000.

Unfortunately, when rainfall is present, scatterometer data can be erroneous. The degree of error is dependent on changes in sea surface roughness caused by the raindrops as well as backscatter and attenuation of the active radar energy from the scatterometer.

To develop a method to account and correct for the erroneous scatterometer data, a collaborative team consisting of a research meteorologist, a university electrical engineer, a government oceanographer and operational National Weather Service meteorologists was formed and funded through the COMET. The group collected and documented the affects of rainfall scatterometer data using in-situ buoy data and land based NEXRAD data. The team is currently in the process of developing a method to correct scatterometer data for the presence of rainfall.

This paper describes the affect of rainfall on scatterometer measurements of sea surface winds, the use of the scatterometer data in an operational setting, the importance of correcting scatterometer data for rainfall, and the current efforts to develop an algorithm to make corrections to the data.