Observational studies in the Kuroshio Extension region, Northwest Pacific—a review and outlook

doi:10.13745/j.esf.sf.2021.3.16

Abstract

Abstract:

The Kuroshio Extension (KE) in the Northwest Pacific is one of the regions that are dynamically most complex, most sensitive to climate change and have the most productive fishing ground in the global ocean. However, it is also a region with the least long-term continuous observation, which can hinder our understanding of the physical, ecological and biogeochemical processes in the region. This paper reviews the recent progress and accomplishments in the international KE observations as well as the ongoing efforts by Chinese scientists-including in 2020 the successful construction of the Kuroshio Extension Mooring System (KEMS), the first real-time data-transmission mooring array in the Northwest Pacific. During the construction of the KEMS, it was found that subduction by eddy lateral advection accounted for more than 50% of the total subduction rate for mode waters. The mesoscale eddies could trap and transport such mode waters southwestward to the western boundary of the subtropical gyre within one and a half year. By simultaneous temperature/salinity measurements and velocity measurement from the mooring arrays, the dynamic features of subthermocline eddies (STEs) in the KE region were examined in detail. For the first time in situ evidence of three types of STEs were obtained in this region, which provided a solid observational basis for further investigation of the detailed generation and erosion mechanisms of the KTEs as well as the global subsurface mass/heat transport processes. The paper proposes that future observational systems should include integrated open-ocean observational platforms for multisphere, multidisciplinary studies, which can provide important observational support for the understanding of multiscale physical biological coupling, deep-ocean energy cascade and its climate effects, and deep-ocean carbon cycle.

Key words: Northwest Pacific, Kuroshio Extension, observation system, multi-sphere, multi-disciplinary

CLC Number:

P714
P721

CHEN Zhaohui, LIN Xiaopei, MA Xin, GUAN Yanfeng, ZHOU Chun, ZHANG Yueqi, MA Ke. Observational studies in the Kuroshio Extension region, Northwest Pacific—a review and outlook[J]. Earth Science Frontiers, 2022, 29(5): 13-22.

Figures/Tables 7

Fig.1 Diagram of ocean material and energy cycle

Fig.2 Diagram of ocean multi-scale processes. Adapted from [4].

Fig.3 Diagram of KESS program. Adapted from [18].

Fig.4 Moored buoys in Kuroshio Extension region

Fig.5 Diagram of Kuroshio Extension Mooring System

Fig.6 Seasonal variation characteristics of potential vorticity (PV) on core layer of model water based on Argo floats. Adapted from [34].

Fig.7 Dual-core STE captured by M1 of KEMS. Adapted from [45].

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