[M-IS13] Integrated Analysis of Geoscience Observations from the Floor to Surface of the Ocean

[MIS13-05] High frequent ocean observations using ARGO floats under explosive cyclones in the Northwestern Pacific

★Invited Papers

*Akira Kuwano-Yoshida^1,2, Shigeki Hosoda³ (1.Disaster Prevention Research Institute, Kyoto University, 2.Application Laboratory, JAMSTEC, 3.Research and Development Center for Global Change, JAMSTEC)

Keywords:Explosive cyclone, ARGO float, atmosphere-ocean interaction

The Northwestern Pacific Ocean is the deepest ocean above which explosive cyclones frequently develop in winter. Numerical simulations of eddy resolving Ocean general circulation model show that explosive cyclones induce large horizontal divergence within the surface-mixed layer and upward flow that reaches 2000 m depth. However, normal observations of ocean cannot capture the oceanic response to explosive cyclones. Sea-surface temperature observations from satellite are not sensitive to explosive cyclones because of deep mixed layer in winter. The time interval of ARGO floats, usually 10 days, is too long to observe rapid change associated with explosive cyclones within 1 day. To observe the oceanic response, high-frequency observations using ARGO floats has been conducted in two winters in 2015/2016 and 2016/2017 in the Northwestern Pacific. The ARGO floats used for the special observations allow real-time change of observation mission including time interval and depth of profile observation through satellite communication. The mission change was operated based on medium-range ensemble forecast data by Japan Meteorological Agency. When an explosive cyclone was predicted with high probability by the forecast, 6-hourly observations with 650 m depth were conducted. Otherwise daily observations with 2000 m depth were conducted between November and March in each winter. 1148 profiles were observed until March 2017, and 73 profiles observed under explosive cyclones. In the presentation, we will show the results for the most explosively developing cyclone on March 1, 2016 among observed cyclones.