Tropical cyclone wind radii composite from the remotely sensed satellite winds

We evaluate the tropical cyclone ocean surface wind observations from the remotely sensedsatellites. The satellite instruments that are capable of measuring the winds near the ocean surface are thescatterometers and the microwave radiometers. The scatterometer is an active radar instrument designedto measure both wind speeds and wind directions by indirectly derive the wind vectors from the measuredradar backscatter at the ocean surface. The scatterometers currently are in orbits include two ASCAT onboard the Metop-A and Metop-B satellites and the Scatsat-1. The microwave radiometer is a radiometricinstrument that are passively collect the brightness temperatures over the ocean surface and the atmosphere.The microwave radiometers currently are in orbits include AMSR-2, SMAP and Windsat. Unlike thescatterometers, the radiometers are capable of measuring only the wind speeds but not wind directionsexcept for the Windsat which are a polarimetric radiometer. In this paper, we use the wind observationsfrom the above scatterometers and the radiometers over the tropical cyclone to create the wind radiicomposite.Each of the satellite orbits will be spatially and temporally collocated within 500-km radius and90-minute time window, respectively, with the tropical cyclone best track data to create the matchup scenesFor each scene, the standard wind radii of 34-knot, 50-knot and 64-knot will be computed and comparedagainst the wind radii reported in the best track and then the normalized wind radii will be determined.Before the wind radii composite will be made, additional step is needed to normalize the different stormheading direction from each scene. The quality flags from each sensor will be applied appropriately.Finally, the wind radii composite will be constructed for each tropical cyclone track for each sensor.Finally, the statistical analysis of the wind radii composite derived from the different satellite sensors willbe presented.