1 / 15

Introduction Methods M odified inverse Empirical search method Data

Circulation in the South China Sea in summer 1998 by a modified inverse model LIU Yonggang, YUAN Yaochu, SU Jilan and JIANG Jingzhong Key Lab of Ocean Dynamic Processes and Satellite Oceanography, SOA, China Second Institute of Oceanography, SOA, China. Introduction Methods M odified inverse

abby
Download Presentation

Introduction Methods M odified inverse Empirical search method Data

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Circulation in the South China Sea in summer 1998 by a modified inverse modelLIU Yonggang, YUAN Yaochu, SU Jilan and JIANG JingzhongKey Lab of Ocean Dynamic Processes and Satellite Oceanography, SOA, China Second Institute of Oceanography, SOA, China • Introduction • Methods Modified inverse Empirical search method • Data • Computed results and discussion Velocity distribution Circulation and mesoscale eddies Volume transport • Summary

  2. Modified inverse model ( Yuan et al., 1992,1998 ) Model equations: Surface B.C. Bottom B.C.

  3. Weighting matrix Matear(1993) Heat inequalities Empirical Search method Fiaderio & Veronis(1982)

  4. Topography, observed stations, sections and computation boxes.(a. Dongsha Islands, b. Xisha Islands, c. Zhongsha Islands, d. Nansha Islands, e. Balawan Island)

  5. Horizontal distribution of water temperature a. 100m, b. 700m, c. 1200m

  6. Geopotential anomaly (10-2m2/s2) referred to 1500 dbar a. Surface, b. 500dbar, c. 1000dbar and ADCP vectors averaged between 25-75m levels

  7. Velocity distribution at sections in the northern SCS (cm/s, + northeastward, - southwestward)a. N1, b. N2, c. N3

  8. Velocity distribution at Sections HV and E1 (cm/s, + eastward, - westward)

  9. Velocity distribution at Sections S3 and S2 (cm/s, + northward, - southward)

  10. ADCP vectors averaged between 25-75m and 75-125m levels and geopotential anomaly (10-2m2/s2) (surface relative to 1500 dbar)

  11. Net volume transport through each station-pair (106m3/s)

  12. Summary Based on the hydrographical and meteorological data obtained by R/V Xiangyanghong No.14 in the South China Sea (SCS) in summer 1998, current velocity and volume transport are calculated by using a modified inverse model. Circulation in the SCS is analyzed by combining the calculated results with ADCP and altimetry data. The following results are obtained. (1) The upper layer circulation in the SCS is quite different from that in the lower layer. In the upper layer, the northern SCS is dominated mainly by a cyclonic gyre, and the central SCS is occupied by two anticyclonic circulation systems and one cyclonic eddy, while in the southern SCS, there is a weak anticyclonic eddy over the Nansha Trough. However, in the deep layer below 500m level, the cyclonic gyre in the northern SCS decreases in scope, and is substituted by an anticyclonic eddy, and the warm eddy west off Philippines also decreases in scope, and the anticyclonic eddy over the Nansha Trough turns cyclonic in the deep layer. (2) There is "multi-eddy phenomenon" in the SCS. A cold eddy east off Vietnam and a warm eddy southeast off Vietnam are the strongest ones, and they have large vertical extents. (3) Western currents are generally stronger than eastern ones except those near the Bashi Strait. (4) Eastward and westward currents exist alternately from the northern to the southern part of the section near the Bashi Strait. (5) A branch of the Kuroshio flows northwestward through the Bashi Strait, and it makes an anticyclonic turn southwest off the Taiwan Island and then flows out of SCS.

More Related