THE STRUCTURE OF TROPICAL CYCLONE BY TOVS AND ITS APPLICATION IN NUMERICAL WEATHER PREDICTION

Abstract:

The TOVS data are used to study the structure of a number of tropical cyclones for the year 2000. Differences are found to some extent between what is found and classic conceptual models in that (1) the horizontal structure is asymmetric and variable so that the low-value centers at low levels of the geopotential height field (or the high-value centers at high levels) do not necessarily coincide with the high-value centers of the temperature field; (2) the vertical structure is also variable in the allocation of the anomalies of the geopotential height field between low values at low levels and high values at high levels. It is especially noted that the centers of the anomalies are tilting at both high and low levels or the high level is only at the edge of a high-pressure zone. There is not any significant high-value anomalous center in a corresponding location with the tropical cyclone. The structure of tropical cyclone in the TOVS is also used as reference to modify the structure of typhoon BOGUS in the numerical prediction model system of tropical cyclones. It is found that the modified BOGUS performs better in coordinating with the environment and predicting the track of the tropical cyclone. The demonstration is two-fold ― the structure of the typhoon BOGUS is such that it means much in the track prediction and the use of the TOVS-based tropical cyclone structure really helps in improving it. It provides the foundation for modification and evolution of typhoon BOGUS.