83rd Annual

Tuesday, 11 February 2003
Diagnostics of Intensive Atmospheric Vortices over the Multiwave Satellite-Derived Sounding Data
Alexander F. Nerushev, Institute of Experimental Meteorology, Obninsk, Russia; and N. V. Tereb and E. K. Kramchaninova
Poster PDF (622.9 kB)
Remote sensing of the ocean-atmosphere system from space is the most efficient method to study tropical cyclone (TC) genesis and to obtain on-line and most complete information on TC parameters. Most important are complexized in time and space soundings of vortices at different wavelengths.

Described are two independent methods proposed by the authors of the paper to determine tropical cyclone parameters (effective dimensions of storm and hurricane wind zones, maximum surface wind speed and minimum pressure in the TC center, depth of hurricane "eye" cloud wall, etc.) important for predicting TC motion, for the preparation of storm warnings, for assessing possible damages, etc. The methods are based on the application of remote sounding data for the ocean-atmosphere system in the UV and microwave spectral ranges. The results are given of definite calculations of tropical cyclones in the Atlantic and Pacific in 1998 and 1999 made with the data of the microwave radiometer SSM/I and the ozone mapper TOMS.

The method of determining the TC characteristics over the data of soundings in the microwave spectrum range is based on the connection of typical features of TC radiobrightness images in the radiometer SSM/I high-frequency channel (85.5 GHz) with the TC structural parameters. Based on the comparison of the results of processing the sounding data of TC in the Atlantic with the data of independent observations accuracy is estimated of the determination of the TC effective dimensions of storm and hurricane wind zones and intensity. It is shown that the relative values of the root-mean-square deviation in the calculated storm and hurricane wind zones effective dimensions from the data of independent observations make correspondingly 23% and 44 %. The absolute values of the root-mean-square deviation practically coincide with the mean spatial resolution of the SSM/I radiometer channels. The estimation of TC intensity is based on the link of maximum surface wind speed and minimum pressure in the cyclone center with the radiobrightness temperature of the hurricane "eye" cloud wall at the frequency of 19.35 GHz.

The method proposed makes it possible to determine a smoothed spatial distribution of the surface wind speed in the whole region of cyclone action from the center to its periphery. Some examples of retrieval of the surface wind speed smoothed spatial structure are given for the TC active zone for several days of its lifetime.

The method of determining TC parameters over the sounding data within the UV spectrum range is based on the connection of the characteristics of the negative ozone anomaly generated by a developing TC with its energy parameters. The calculation results demonstrate that the highest connection of the negative ozone anomaly characteristics determined from the TOMS data is observed with the effective dimensions of the storm and hurricane wind zones.

The effective dimensions of the Atlantic TC storm and hurricane wind zones calculated with the use of two independent methods are compared.

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