Sea Surface Temperature (SST) is crucial for the development and maintenance of a tropical cyclone(TC) particularly below the storm core region. However, storm data below the core region is the mostdifficult to obtain, hence it is not clear yet that how sensitive the radial distribution of the SST impactthe storm characteristic features such as its inner-core structures, translational speed, track, rainfalland intensity particularly over the Bay of Bengal. To explore the effects of radial SST distributionon the TC characteristics, a series of numerical experiments were carried out by modifying the SSTat different radial extents using two-way interactive, triply-nested, nonhydrostatic Advanced WeatherResearch and Forecast (WRF-ARW) model. It is found that not only the SST under the eyewall (coreregion) contribute significantly to modulate storm track, translational speed and intensity, but also thoseoutside the eyewall region (i.e., 2–2.5 times the radius of maximum wind (RMW)) play a vital role indefining the storm’s characteristics and structure. Out of all the simulated experiments, storm wherethe positive radial change of SST inducted within the 75 km of the storm core (i.e., P75) produced thestrongest storm. In addition, N300 (negative radial changes at 300 km) produced the weakest storm.Further, it is found that SST, stronger within 2–2.5 times of the RMW for P75 experiment, plays adominant role in maintaining 10 m wind speed (WS10), surface entropy flux (SEF) and upward verticalvelocity (w) within the eyewall with warmer air temperature (T) and equivalent potential temperature(θe) within the storm’s eye compared to other experiments.
Volume 128 | Issue 8
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