Tuesday, 16 January 2007
The WindSat passive microwave radiometer: forecaster applications
Exhibit Hall C (Henry B. Gonzalez Convention Center)
Launched in 2003, the WindSat instrument aboard the Coriolis satellite is the first space borne fully polarimetric microwave radiometer specifically designed to retrieve ocean surface wind speeds and direction. A research prototype, it has successfully demonstrated this capability in preparation for future polar orbiting environmental satellites. This poster explores how wind vector retrievals can be exploited by forecasters to assess the marine environment. First, we explore potential applications for WindSat, including: 1.assessing topographic influences on winds in the nearshore environment, including the effects of headlands, terrain gaps, and islands; 2. investigating relatively unobserved oceans of the world including the Arctic and Antarctic; 3. use of WindSat retrievals and other products in or around tropical cyclones; 4. introducing the potential of WindSat for data assimilation. In these applications we compare WindSat retrievals to those of QuikScat, the latter being much more familiar to forecasters. Some limitations of WindSat are: 1. compared to QuikScat, the retrievals of WindSat are more degraded in the presence of heavy cloudiness and especially precipitation; 2. WindSat directional accuracies are degraded at low speeds; 3. It can not estimate winds closer to shore than about 50 km, compared to QuikScat that can accurately measure winds within about 25 km. One particular advantage of WindSat is that it has polarimetric receiving capabilities at three channels, permitting the retrieval of rain rate, cloud liquid water, total precipitable water, and sea ice concentration, in addition to the wind vector. Thus, unlike QuikScat, rain and cloud contamination can be quantified specifically. We illustrate the capabilities of WindSat in a series of case examples.