A Coupled Numerical Modeling Study of a Sea Fog Case After the Passage of Typhoon Muifa Over the Yellow Sea in 2011. Issue 3 (8th February 2021)

• Record Type: Journal Article
• Authors: Kim, Subin; Moon, Jae‐Hong; Kim, Taekyun
• Is Part Of: Journal of geophysical research. Volume 126:Issue 3(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-02-08
• Subjects: air‐sea coupling -- atmospheric stability -- horizontal moisture convergence -- sea fog forecast -- sea surface cooling; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2020JD033875
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Satellite remote sensing data revealed a widespread sea fog event over the central/southern Yellow Sea (YS), following Typhoon Muifa passage in August 2011. Despite the importance of sea fog prediction for coastal safety, improving accuracy remains a challenging issue. By analyzing results from air‐sea coupled and uncoupled simulations, this study aims to investigate how the air‐sea coupling improves the sea fog formation and duration and examine atmospheric responses to spatiotemporally varying sea surface temperature (SST) over the YS. Unlike the uncoupled model, the SST simulated by the coupled model dramatically decreased and maintained its low temperature for more than a week after the typhoon passed over the YS, showing better agreement with the observations. The sharp SST decrease over the YS cools the air temperature at low‐level atmosphere and enhances horizontal convergence in the moisture flux over the cooler ocean, which provides favorable conditions for sea fog formation. The long‐lasting oceanic cooling stabilizes the atmospheric boundary layer and suppresses atmospheric vertical mixing, delaying the dissipation of sea fog for more than a week. This study highlights that air‐sea coupling can improve the sea fog simulation by providing more realistic oceanic conditions. Plain Language Summary: Because sea fog poses a severe risk to many human activities, such as shipping and aviation in coastal regions, accurately predicting the sea fog is of extreme importance for coastal and marine safety. Despite its importance, improving the sea fog simulation still remains a challenging issue. In this study, we investigate how air‐sea coupling improves the accuracy of sea fog simulation and analyze atmospheric responses to spatial and temporally varying sea surface temperature (SST) over the Yellow Sea (YS). To do so, we used a fully coupled ocean–atmosphere modeling system and computed comparative experiments of coupled and uncoupled simulation for Typhoon Muifa that passed over the central YS in August 2011. The comparison shows that typhoon‐induced SST cooling enhances horizontal convergence in moisture flux and vertical stability, providing favorable conditions for the formation and duration of sea fog. This study demonstrates that air‐sea coupling is instrumental in producing oceanic and atmospheric conditions and simulating associated extreme weather events in the YS. Key Points: Abrupt and widespread sea surface temperature cooling occurred with decreasing surface air temperature due to typhoon‐induced strong vertical mixing in the Yellow Sea Oceanic cooling enhances horizontal convergence in moisture flux and vertical stability, providing favorable conditions for sea fog formation Air‐sea coupling improves sea fog simulation by providing more rapidly altered oceanic conditions