Presenting Author: Frank Wentz
Wind measurements from satellites are vital to climate research and weather prediction. A variety of satellite sensors provide estimates of the wind over the oceans by measuring the sea-surface roughness. These sensors include scatterometers, polarimetric radiometers, and conventional radiometers, the latter of which provide only wind speed. In the pursuit of providing the community with better satellite wind products from all these sensors, we focused on a number of calibration and algorithmic issues. First, we're developing a new retrieval algorithm for conventional radiometers (i.e., SSMI and AMSR) that will provide useful wind speed measurements in storms and hurricanes. The existing wind algorithms for satellite microwave (MW) radiometers perform very poorly in the presence of rain, typically giving spuriously high winds. Paradoxically, NOAA's primary airborne sensor for measuring tropical cyclone wind speed is also a MW radiometer: the Step Frequency Microwave Radiometer (SFMR). We will report some preliminary results of the retrieval storm winds. The second activity is the precise calibration and optimum interpolation of WindSat observations. WindSat is the first fully polarimetric radiometer in space. For a number of reasons, the calibration, data handling, sampling, and retrieval algorithms for WindSat are more complex than for previous radiometers. These complexities have somewhat masked the true capabilities of this sensor. We will present a number of advanced methods for processing the WindSat observations. Other activities include redevelopment of the QuikScat geophysical model function (GMF) and cal/val for the European scatterometer ASCAT. Now that we have nearly a decade of QuikScat observations, it seems prudent to review the QuikScat GMF and make improvements where necessary. We investigate whether the amplitude of the harmonics continues to increase with wind speed or does the relationship flatten out. We also explore the effect of ocean currents on the buoy versus QuikScat intercomparisons used in the original GMF derivations.
2019 International OVWST Meeting
May 29-31 in Portland, Maine, USA