An objective method for estimating tropical cyclone intensity and structure from NOAA-15 Advanced Microwave Sounder Unit (AMSU) data

The Advanced Microwave Sounder Unit (AMSU) on the NOAA-15 satellite has much greater horizontal and vertical resolution than the Microwave Sounder Unit (MSU) on previous NOAA polar-orbiting satellites. AMSU retrieval techniques provide temperature soundings from near the surface to above 50 hPa and vertically integrated measurements of atmospheric moisture with a horizontal resolution of up to 50 km. The pressure, density, and tangential winds as a function of radius and height were calculated from the AMSU temperature profiles using hydrostatic and gradient balance for about 100 Atlantic and East Pacific tropical cyclone cases from the 1999 hurricane season. Parameters from these analyses are used to develop an objective method for estimating tropical cyclone intensity. Preliminary results suggest this method performs best for tropical storms and weak hurricanes, where the objective version of the Dvorak method, based upon GOES Infrared imagery, is less reliable. The potential for using the AMSU analyses to estimate the radii of 34 and 50 kt winds will also be described.