[A-CG32] Extratropical oceans and atmosphere

[ACG32-15] Climatic Hotspot2 project for further understandings of mid-latitude air-sea interactions

*Masami Nonaka¹ (1.Application Laboratory, Japan Agency for Marine-Earth Science and Technology)

Keywords:air-sea interactions, mid-latitude, Climatic hotspot

The frequency of extreme rainfall and snowfall has increased in recent years, and these events severely affect human life and property. It has been considered that tropical ocean and atmosphere variability, as well as the warming climate, remotely influence mid-latitude extreme weather/climate, while the mid-latitude ocean is passive to atmospheric variability. However, recent analyses of high-resolution ocean/atmospheric data have revealed that the mid-latitude ocean also influences atmospheric circulations and their variability. By rediscovering the strong warm current and associated strong ocean frontal zones as a “climate hotspot”, we have elucidated mechanisms of ocean-atmosphere interactions in the mid-latitudes. The progress in research has prompted a new crucial task: the application of such new knowledge to prediction of extreme rainfall/snowfall and climate variability. For this new task, the five-year research project “Climatic Hotspot2”, started in 2019, has conducted studies to further our understanding of mid-latitude ocean-atmosphere interaction processes. In the project, several observational campaigns and high-resolution oceanic and atmospheric numerical modeling studies have been conducted. These studies have revealed the crucial influence of ocean currents and oceanic surface and subsurface structures on climate extreme events. In this presentation, we introduce the results of the projects to summarize the project.