An Estimation of Typhoon Intensity and the Prediction of Its Track by Using MSU Data

Abstract

This study uses both airborne and NOAA (National Oceanic and Atmospheric Administration) MSU (Microwave Sounding Unit) observational data, covering the Taiwan area during 1990 TATEX (Taiwan Area Typhoon Experiment) period to develop a typhoon intensity estimation model. Although some previous studies have shown that the temperature difference of the typhoon center and its environment estimated by the MSU at 250-mb level has a positive relationship with the maximum wind speed, the results in this paper show that they are not as satisfactory as expected. When using only the 250-mb temperature anomaly, the value of the correlation is roughly about 0.6, and the RMSE (Root Mean Square) being 19kts. According to the sensor readings of the weighting function, this outcome suggests that the maximum typhoon wind speed is strongly related to the brightness temperature, which is contributed throughout each layer of the typhoon. Thus, the wind speed information is not complete when only the upper levels of the temperature information are considered. Because the weighting function of the third MSU information can be extracted for the predicting the typhoon intensity accuracy with the correlation and RMSE equaling 0.7 and 16.5kts, respectively when both the 250 and 700-mb temperature anomalies are considered simultaneously.

We also used a 700-mb cold-core location in predicting the path a typhoon follows. The results showed a value of 0.9 R-squared and an RMSE of 13.1 degrees in angle. Generally speaking, the results were rather impressive and pave the way for further exploration of the method's potential application in monitoring a typhoon's track.

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