Water exchange through the Kerama Gap estimated with a 25-year Pacific HYbrid Coordinate Ocean Model

• Published in: Chinese journal of oceanology and limnology Vol. 35; no. 6; pp. 1287 - 1302
• Main Author: 周文正;于非;南峰
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.11.2017; Springer Nature B.V
• Subjects: Annual variations; Autumn; correlation; Earth and Environmental Science; Earth Sciences; East China Sea; environmental models; Estimating techniques; Hybridization; Limnology; Ocean models; Oceanography; Oceans; Pacific Ocean; Physics; Ryukyu Archipelago; Science; spring; Summer; Transport; Upstream; Variation; Water exchange; Water resources; 估计; 太平洋; 年际变化; 换水; 标准偏差; 海洋模式; 混合坐标; 间隙; Pacific Ocean; East China Sea; Ryukyu Archipelago; Kuroshio; Ryukyu Current; Kerama Gap; HYbrid Coordinate Ocean Model (HYCOM); water exchange
• ISSN: 0254-4059; 2096-5508; 1993-5005; 2523-3521
• DOI: 10.1007/s00343-017-6141-2

Variations in water exchange through the Kerama Gap （between Okinawa Island and Miyakojima Island） from 1979 to 2003 were estimated with the 0.08° Pacific HYbrid Coordinate Ocean Model （HYCOM）. The model results show that the mean transport through the Kerama Gap （KGT） from the Pacific Ocean to the East China Sea （ECS） was 2.1 Sv, which agrees well with the observed mean KGT （2.0 Sv） for 2009- 2010. Over the time period examined, the monthly KGT varied from -10.9 Sv to 15.8 Sv and had a standard deviation of ＋5.0 Sv. The water mainly enters the ECS via the subsurface layer （300-500 m） along the northeastern slope of the Kerama Gap and mainly flows out of the ECS into the southwest of the Kerama Gap. The seasonal and interannual variations of the KGT and the Kuroshio upstream transport were negatively correlated. The Kuroshio upstream transport was largest in summer and smallest in auamm while the KGT was smallest in summer （1.02 Sv） and largest in spring （2.94 Sv） and autumn （2.44 Sv）. The seasonal and interarmual variations in the Kuroshio downstream （across the PN-line） transport differed significantly from the Kuroshio upstream transport but corresponded well with the KGT and the sum of the transport through the Kerama Gap and the Kuroshio upstream, which indicates that information about variation in the KGT is important for determining variation in the Kuroshio transport along the PN-line.