Impact Propagation of Radiosonde Data Assimilation over the Kuroshio and Kuroshio Extension: Case Study on the Early Summer (Baiu) in 2012

Journal of the Meteorological Society of Japan

Takeshi ENOMOTO¹  Akira KUWANO-YOSHIDA¹  Qoosaku MOTEKI²  Atsuyoshi MANDA³  Hisashi NAKAMURA⁴  Yoshimi KAWAI⁶ 

[1] Application Laboratory, Japan Agency for Marine–Earth Science and Technology, Yokohama, Japan;Department of Coupled Ocean-Atmosphere-Land Processes Research, Japan Agency for Marine–Earth Science and Technology, Yokosuka, Japan;Disaster Prevention Research Institute, Kyoto University, Uji, Japan;Graduate School of Bioresources, Mie University, Tsu, Japan;Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan;Research and Development Center for Global Change, Japan Agency for Marine–Earth Science and Technology, Yokosuka, Japan

关键词: data assimilation;    radiosonde;    Kuroshio;    North Pacific;    observing system experiment;   

DOI  :  10.2151/jmsj.2017-004

学科分类：大气科学

来源: Meteorological Society of Japan

【 摘 要 】

 The present study investigated how impacts of the inclusion of radiosonde observations conducted locally in the early summer of 2012 over the Kuroshio and Kuroshio Extension (KE) can spread over time across the North Pacific basin to influence the predictability of synoptic and large-scale tropospheric circulation. For that purpose, observing system experiments (OSEs) were performed where each of two extra sets of radiosonde data, one obtained over the East China Sea in mid-May and the other over the KE in early July, was added to an atmospheric ensemble data assimilation system for comparison with the corresponding analyses without those data. The experiments show that the impact of the extra data assimilated propagates eastward mainly due to advection by the subtropical jet (STJ) in May and July. The strong STJ in May allows the upper-tropospheric impact to travel across the basin only within two days. Under the weaker STJ, the corresponding impact in July tends to remain within the western Pacific, until it eventually reaches the eastern portion of the basin. Assimilation of the extra radiosonde data over the Kuroshio or KE can lead to a decrease of pressure over the Gulf of Alaska in both May and July.

【 授权许可】

Unknown