Early Rapid Intensification of Typhoon Nepatak and Its Cause

Abstract

Rapid intensification of tropical cyclones deserves a special attention, since its damage can be disastrous without much time for evacuation. Further early intensification is worth examining the mechanism of its generation. Typhoon Nepatak got intensified as strong typhoon of category 5, early July in 2016, in the Northwestern Pacific, lasting nearly two days as category 5. Typhoon Nepatak lasts extraordinarily as category 5 from 00h 06Jul16 to 12h 07Jul16, even in early summer. Since ocean heat energy is expected to ultimately contribute to the intensification of tropical cyclones, the near 10 year-long argo profile data of 2006 to 2016 have been collected, first, The ocean heat content (OHC) over 26&#8304 C appears to range over 80 KJ/cm2, even reaching over 100 KJ/cm2, from available argo profile data, and we succeeded in finding the cases showing the high OHC signals over 80 KJ/cm2 along the tracks, suggesting the possibility of the positive correlation. Meanwhile, the argo profile data are not many enough to compare the OHC values from argo data with intensity changes all along the tracks, due to the scarcity of data along the propagation tracks of the typhoon Nepatak. Therefore, we collected model results available. The model rusults from HYCOM, NEMO, and MOM5 are also used to compute the heat content along the track. It is likely that the high OHC value originating from many eddies in the low latitude regak got intensified as strong typhoon of category 5, early July in 2016, in the Northwestern Pacific, lasting nearly two days as category 5. Typhoon Nepatak lasts extraordinarily as category 5 from 00h 06Jul16 to 12h 07Jul16, even in early summer. Since ocean heat energy is expected to ultimately contribute to the intensification of tropical cyclones, the near 10 year-long argo profile data of 2006 to 2016 have been collected, first, The ocean heat content (OHC) over 26&#8304 C appears to range over 80 KJ/cm2, even reaching over 100 KJ/cm2, from available argo profile data, and we succeeded in finding the cases showing the high OHC signals over 80 KJ/cm2 along the tracks, suggesting the possibility of the positive correlation. Meanwhile, the argo profile data are not many enough to compare the OHC values from argo data with intensity changes all along the tracks, due to the scarcity of data along the propagation tracks of the typhoon Nepatak. Therefore, we collected model results available. The model rusults from HYCOM, NEMO, and MOM5 are also used to compute the heat content along the track. It is likely that the high OHC value originating from many eddies in the low latitude reg