Influence of the Kuroshio Interannual Variability on the Summertime Precipitation over the East China Sea and Adjacent Area

Abstract

Much attention has been paid to the climatic impacts of changes in the Kuroshio Extension, instead of the Kuroshio in the East China Sea (ECS). This study, however, reveals the prominent influences of the lateral shift of the Kuroshio at interannual time scale in late spring [April–June (AMJ)] on the sea surface temperature (SST) and precipitation in summer around the ECS, based on high-resolution satellite observations and ERA-Interim. A persistent offshore displacement of the Kuroshio during AMJ can result in cold SST anomalies in the northern ECS and the Japan/East Sea until late summer, which correspondingly causes anomalous cooling of the lower troposphere. Consequently, the anomalous cold SST in the northern ECS acts as a key driver to robustly enhance the precipitation from the Yangtze River delta to Kyushu in early summer (May–August) and over the central ECS in late summer (July–September). In view of the moisture budget analysis, two different physical processes modulated by the lateral shift of the Kuroshio are identified to account for the distinct responses of precipitation in early and late summer, respectively. First, the anomalous cold SST in the northern ECS induced by the Kuroshio offshore shift is likely conducive to the earlier arrival of the mei-yu–baiu front at 30°–32°N and its subsequent slower northward movement, which may prolong the local rainy season, leading to the increased rain belt in early summer. Second, the persistent cold SST anomalies in late summer strengthen the near-surface baroclinicity and the associated strong atmospheric fronts embedded in the extratropical cyclones over the central ECS, which in turn enhances the local rainfall.

Interaction of the Westerlies with the Tibetan Plateau in Determining the Mei-Yu Termination

“…merits further investigations. Recent studies suggest that variation of sea surface temperature over the East China Sea to the northwestern Pacific affect seasonal migration (Gan et al, 2019) and intensity (Kuwano-Yoshida et al, 2013) of the mei-yu-baiu rainband.…”

A Mesoscale Ocean–Atmosphere Coupled Pathway for Decadal Variability of the Kuroshio Extension System

“…The time-lagged maximum covariance analysis (MCA) was first used in the pioneering work of Czaja and Frankignoul (2002) to study the impact of Atlantic SST anomalies on the North Atlantic Oscillation (NAO). Afterwards, this powerful analysis tool has been widely used in the studies seeking for the climatic imprints of the midlatitude oceanic variability in the presence of internal atmospheric variability (e.g., Frankignoul and Kestenare 2005;Liu et al 2006;Wu 2013, 2015;Wen et al 2016;Zhang et al 2018;Gan et al 2019…”

Interannual and decadal variations of the Kuroshio axis in the East China Sea

“…The Kuroshio carries a huge amount of heat from the tropics to ECS, as the strongest ocean current in coastal water of China, the Kuroshio in ECS is considered to significantly impact on the hydrography, fisheries, and plays a very important role in the climate change of East Asia (Nitani 1972 [1][2][3][4] [5][6] [7][8] [9] . In the last thirty years, the Kuroshio transport (KT) has attracted much attention due to the periodic variations and remote responses to the climate signals in the Pacific Ocean including the Pacific decadal oscillation (PDO) and the El Niño-Southern Oscillation (ENSO), although to what extent such the relationship between the KT and path meander in the ECS and the climate signals remains poorly understood.…”