Upper ocean response to tropical cyclone wind forcing： A case study of typhoon Rammasun （2008）

• Published in: 中国科学：地球科学英文版 2015 (9), p.1623-1632
• Main Author: PEI YuHua ZHANG RongHua CHEN DaKe
• Format: Article
• Language: English
• Subjects: Argo资料; 上层海洋; 台风中心; 海洋环流模式; 热带气旋; 表面层; 西北太平洋; 风强
• ISSN: 1674-7313; 1869-1897

The characteristics of the upper ocean response to tropical cyclone wind （TCW） forcing in the northwestern Pacific were in- vestigated using satellite and Argo data, as well as an ocean general circulation model. In particular, a case study was carried out on typhoon Rammasun, which passed through our study area during May 6-13, 2008. It is found that the local response fight under the TCW forcing is characterized by a quick deepening of the surface mixed layer, a strong latent heat loss to the atmosphere, and an intense upwelling near the center of typhoon, leading to a cooling of the oceanic surface layer that persists as a cold wake along the typhoon track. More interestingly, the upper ocean response exhibits a four-layer thermal structure, including a cooling layer near the surface and a warming layer right below, accompanied by another pair of cooling/warming layers in the thermocline. The formation of the surface cooling/warming layers can be readily explained by the strong vertical mixing induced by TCW forcing, while the thermal response in the thermocline is probably a result of the cyclone-driven upwelling and the associated advective processes.