High frequency wind-related seasonal mean latent heat flux changes
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High frequency wind‑related seasonal mean latent heat flux changes Renguang Wu1,2,3 · Yuqi Wang2,4 · Yang Jiao5 Received: 13 April 2020 / Accepted: 23 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Surface latent heat flux (LHF) is an important component in the heat exchange between ocean and atmosphere. Seasonal mean LHF changes are often interpreted using seasonal mean wind changes. The present study analyzes the high-frequency wind-induced seasonal mean LHF changes. The changes in daily mean variables are decomposed into synoptic, intraseasonal, and low-frequency components and the respective contributions of the three components to seasonal mean LHF are estimated based on the bulk formula. It is shown that the high-frequency wind-induced LHF contributes an important part to climatological seasonal mean LHF and year-to-year variations of seasonal mean LHF in regions where low-frequency seasonal mean winds are weak, in particular, over the tropical Indian Ocean and western Pacific. A prominent feature is that the high-frequency and low-frequency wind-induced LHF anomalies tend to be opposite in those weak wind regions. In these regions, the reduced seasonal mean winds suppress seasonal mean wind-related LHF, but favors the accumulation of the high-frequency wind-induced LHF that increases in both active and inactive phases of high-frequency variations. Due to the shift of weak seasonal mean wind region with the low-frequency wind variations, the region of prominent high-frequency wind-induced seasonal mean LHF displaces with the season. The present results indicate an important upscale feedback of high-frequency wind variations to seasonal mean LHF. Keywords Latent heat flux · Low and high frequency components · Wind speed effects · Seasonal move
1 Introduction Latent heat flux (LHF) is an important component in the air-sea heat exchange. It plays an important role in the formation of several climate modes in the tropics. The development of the tropical Atlantic meridional mode is shown to be closely related to the wind-evaporation effect (Chang et al.
* Renguang Wu [email protected] 1
Department of Atmospheric Sciences and Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province, School of Earth Sciences, Zhejiang University, Hangzhou, China
2
Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
3
Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
4
College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
5
Guangzhou Meteorological Observatory, Guangzhou, China
1997; Ruiz-Barradas et al. 2000; Chiang and Vimont 2004). The formation of the Indian Ocean dipole mode in boreal summer is associated with a positive wind-evaporation feedback in southeastern tropical Indian Ocean (Saji et al. 1999; Webster et al. 1999; Huang and Kinter 2002; Wang et al. 2003). The maintenance of an anomalous anticyclone i
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