Environmental modulators such as ocean heat content (OHC) and vertical wind shear (VWS) influence on the intensity change of tropical cyclones (TCs). Park et al. (2012; Tropical Cyclone Research and Review) showed that OHC and VWS influence the intensity change of TCs in terms of a two-dimensional phase diagram (hereafter PEH diagram) using reanalysis data for the atmosphere and ocean. They showed an interesting result, however, were not able to evaluate the relationship between them correctly. In the present study, we try to evaluate the relationship between them for T1013 (Megi) using a coupled atmosphere-ocean non-hydrostatic model, Cloud Resolving Storm Simulator (CReSS) and Non-Hydrostatic Ocean model for Earth Simulator (NHOES), CReSS-NHOES with horizontal grid resolution of 0.02 degree both for latitude and longitude (approximately 2 km). The simulation is conducted for 7 days from 00 UTC on October 14, 2010, after one day of the formation of T1013.
The simulation well reproduces its track and the tendency of minimum central pressure. The reproduced minimum central pressure (889 hPa) corresponds the observed one (885 hPa). When T1013 intensifies, VWS between 850 and 200 hPa is lesser than 6 m s-1 and OHC defined by heat content above the depth of 26 degree Celsius is larger than 90 kJ cm-2. These environmental modulators are suitable for the intensification of TCs shown in previous studies. When T1013 suppresses its intensity, VWS increases above 7.5 m s-1 and OHC decreases below 90 kJ cm-2. Using the PEH diagram, we reproduce well the relationship between these modulators and the intensification of T1013.
As a result, the impact of the dynamical process around the center of TCs on the environment (VHS) should be needed to evaluate the intensity change of TCs. The interaction of TCs and ocean should be included to evaluate it.