Horizontal winds at 850 hPa from tropical cyclones retrieved using the nonlinear balance equation, where the mass field was determined from Advanced Microwave Sounding Unit (AMSU) temperature soundings, are compared with the surface wind fields derived from NASA’s Quick Scatterometer (QuikSCAT) and Hurricane Research Division H*Wind analyses. It was found that the AMSU-derived wind speeds at 850 hPa have linear relations with the surface wind speeds from QuikSCAT or H*Wind. There are also characteristic biases of wind direction between AMSU and QuikSCAT or H*Wind. Using this information to adjust the speed and correct for the directional bias, a new algorithm was developed for estimation of the tropical cyclone surface wind field from the AMSU-derived 850-hPa winds. The algorithm was evaluated in two independent cases from Hurricanes Floyd (1999) and Michelle (2001), which were observed simulta-neously by AMSU, QuikSCAT, and H*Wind. In this evaluation the AMSU adjustment algorithm for wind speed worked well. Results also showed that the bias correction algorithm for wind direction has room for improvement.

The Advanced Microwave Sounding Unit (AMSU) has better horizontal resolution and vertical temperature sounding abilities than its predecessor, the Microwave Sounding Unit (MSU). Those improved capabilities are demonstrated with observations of two cyclonic weather systems located in the South Pacific Ocean on 1 March 1999. These weather systems appear quite similar in conventional infrared satellite imagery, suggesting that they are comparable in structure and intensity. However, an analysis using temperature retrievals created from the AMSU shows that their vertical thermal structure is quite different. This is just one example of an application highlighting the improved sounding capabilities available with the AMSU instrument suite. A preliminary look at what the AMSU can provide in data-void regions and a discussion of future plans to create AMSU-based products to better diagnose synoptic-scale weather systems are presented.

A neural network approach for temperature retrieval from AMSU-A measurements onboard NOAA-15 and NOAA-16 satellites and a case study during Gonu cyclone

A neural network approach for temperature retrieval from AMSU-A measurements onboard NOAA-15 and NOAA-16 satellites and a case study during Gonu cyclone Atmósfera, vol. 23, núm. 3, enero, 2010, pp. 225-239

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Abstract not found

Scientific progress often comes about as a result of new instruments for making scientific observations. The Advanced Microwave Sounding Unit (AMSU) is

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. 1.

A method is described of retrieving a mean spatial structure of wind speed near a sea surface spatial structure in zones of intensive atmospheric vortices action from the data of sounding the ocean-atmosphere system in the microwave wavelength range. The method can be used for vortices with distinct structural parameters – the eye, the eye cloud wall, zones of hurricane and storm winds. Tropical cyclones and polar mesocyclones (Polar Lows) can be in the number of such vortices. The basic idea of the method is that the knowledge of major structural parameters of atmospheric vortices (effective dimensions of the storm and hurricane wind zones, maximum wind speed and effective dimensions of maximum winds) gives a possibility to determine a mean spatial distribution of wind speed near a sea surface in the whole region of vortex action – from the center to periphery. The structural parameters can be determined on the basis of their connection (found experimentally) with characteristics of the vortex radiobrightness images in different channels of a radiometer. The effective dimensions of the storm and hurricane wind zones can be determined from the data of soundings not only in the microwave but also in the UV wavelength range. The accuracy of determining the major structural parameters of atmospheric vortices was estimated based on the examples of processing sounding data of tropical cyclones in the Northern Atlantic and North-West Pacific obtained with the use of the microwave radiometer SSM/I and the ozone mapper TOMS and after a comparison with the data of independent measurements. Presented are the calculation results of wind speeds near the sea surface in the tropical cyclones in the Atlantic and Pacific in 1994, 1998 and 1999. 1.

The 2001 northern hemisphere hurricane season marks the third year of passive microwave warm core observations using the NOAA-KLM series Advanced