Study of dissolved oxygen responses to tropical cyclones in the Bay of Bengal based on Argo and satellite observations

Huabing Xu; Danling Tang; Jinyu Sheng; Yupeng Liu; Yi Sui

doi:10.1016/j.scitotenv.2018.12.384

Study of dissolved oxygen responses to tropical cyclones in the Bay of Bengal based on Argo and satellite observations

Sci Total Environ. 2019 Apr 1:659:912-922. doi: 10.1016/j.scitotenv.2018.12.384. Epub 2018 Dec 26.

Authors

Huabing Xu¹, Danling Tang², Jinyu Sheng³, Yupeng Liu¹, Yi Sui³

Affiliations

¹ Guangdong Key Laboratory of Ocean Remote Sensing, State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China.
² Guangdong Key Laboratory of Ocean Remote Sensing, State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China. Electronic address: Lingzistdl@126.com.
³ Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada.

PMID: 31096421
DOI: 10.1016/j.scitotenv.2018.12.384

Abstract

Effects of tropical cyclones (TCs) on dissolved oxygen (DO) in subsurface waters (20-200 m) over the Oxygen Minimum Zones (OMZs) in the Bay of Bengal (BoB) are examined based on Argo and satellite data. Five TCs (Hudhud, Five, Vardah, Maarutha and Mora) during 2013-2018 are considered. Analyses reveal three types of DO temporal variability caused by the storm-induced mixing and upwelling. The first type features temporal DO increases in subsurface waters (37-70 m) caused mainly by intense vertical mixing and downwelling. The second type features DO reductions in subsurface waters after the storms attributed to storm-induced upwelling. The third type features temporal DO increases at depths between 40 and 79 m and decreases at depths between 80 and 150 m due to the combined effect of strong vertical mixing and upwelling. These three types of DO responses can occur in different areas, depending on TC intensity, translational speed and Ekman pumping. The temporal DO variability is also influenced by the shallow oxycline (58.3 ± 16.7 m), mesoscale eddies and biochemical processes. Due to TC intensification, a pre-existing oceanic cyclonic eddy produced a large upwelling and induced a long time of DO decrease in the subsurface layer. This study suggests three different types of DO responses along the TC track in the OMZ, which is useful to evaluate the influence of TCs on the OMZ.

Keywords: DO; Mesoscale eddy; Mixing; Oxygen Minimum Zone; Tropical cyclone; Upwelling.