The tropical cyclone intensity estimation based on MODIS data: a case study

Knowledge of tropical cyclone intensity is good for pre-analysis on its development and its possible damage. It is the lack of observations in situ and the drawback of numerical model that make the remotely sensing from space be a useful method for tropical cyclone study. In this paper, a preliminary study on estimating tropical cyclone intensity by using MODIS (Moderate Resolution Imaging Spectroradiometer) data is present. The typhoon 0922 Nida is as a case for this study and the maximum wind speed in the cyclone is used to an index of cyclone intensity. By detecting the typhoon body from MODIS observation, the eyewall and edge of Nida is identified. The cloud-top height and cloud-top temperature in tropical cyclone region, which are two key parameters for estimating tropical cyclone intensity, is also obtained from MODIS observations. The retrieved cloud-top height is compared and validated with the CloudSat radar observations, which just cross the neighborhood of the 0922 storm center. According to a physically based framework, the maximum wind speed is estimated approximately from the background sea surface temperature, cloud-top temperature and cloud-top height. A simple result indicates that the technique for estimating cyclone intensity from MODIS observation is feasible. On the other hand, the future applications and some potential uncertainties on means are needed to be on second thoughts and discussed.