[A-OS18] Kuroshio Large Meander

[AOS18-05] Comparison of the processes of their response to the Kuroshio Large Meander between explosive cyclones that differ in the development type

*Hidetaka Hirata¹, Ryuichi Kawamura², Masami Nonaka³ (1.Rissho University, 2.Kyushu University, 3.Japan Agency for Marine-Earth Science and Technology)

Keywords:Explosive cyclone, Kuroshio Large Meander, Cloud Resolving Model

Recent studies pointed out that the Kuroshio Large Meander affects the development of extratropical cyclones. However, the processes related to the cyclones’ response to the Kuroshio Large Meander are still under debate. This study conducted multiple numerical sensitivity experiments with respect to sea surface temperature (SST) and examined the processes of their response to the Kuroshio Large Meander between extratropical cyclones that differ in the type of the intensification. We focused on two explosively developing extratropical cyclones: One is a cyclone that developed mainly due to the diabatic process (case 1), and the other is a cyclone that intensified primarily due to the baroclinic process (case 2). In both cases, the decreases in the central pressure of cyclones were suppressed in experiments with cold SST anomalies associated with the Kuroshio Large Meander path, compared with experiments with warm SST anomalies associated with the Kuroshio Straight path. Thus, the response of the cyclone central pressure to the SST anomalies of cases 1 and 2 were similar. However, primary causes leading to the cyclones’ response differed between the two cases. In case 1, the SST anomalies derived from the variation of the Kuroshio path influenced the time evolution of the cyclone central pressure through the diabatic process. On the other hand, in case 2, the SST anomalies affected the central pressure via the baroclinic process. These results suggest that the main process causing the cyclones' response to the Kuroshio Large Meander varies owing to the development types.