摘要: |
根据“向阳红五号”调查船于1992-1993年TOGA-COARE(Tropical Ocean and Global Atmosphere-Coupled Ocean Atmosphere Response Experiment)强化观测期(IOP)期间,在赤道西太平洋观测到的CTD、海面气象等资料,计算了海表barrier layer(壁垒层)厚度。并对该海区壁垒层厚度的变化特征及机制作初步分析研究。结果表明,该海区观测期间壁垒层平均厚度为11.9m,较历史平均值薄,并有明显的逐日变化。局地强降水及海面风速主要通过影响海表混合层深度的变化,大尺度风场、流况主要通过影响等温层深度的变化而使壁垒层厚度发生变化。 |
关键词: TOG-COARE 赤道西太平洋 壁垒层 |
DOI: |
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基金项目:国家海洋局耦合海气响应实验项目91-4-08号 |
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OBSERVATION AND ANALYSIS OF BARRIER LAYER IN THE WESTERN EQUATORIAL PACIFIC DURING TOGA-COARE IOP |
XU Bing-rong,Lin Chuan-lan,DoNG Ru-zhou,LI Shan-hua
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Second Institute of Oceanography, State Oceanic Administration, Hangzhou, 310012
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Abstract: |
Analyses of the variational features and mechanism of the barrier layer thickness (Db) in the Western equatorial Pacific using data collected by the R/V “Xiangyonghong 5" during TOGA-COARE IOP cruises showed that:
(1) During the observational period the mean of Db is 11.9 m, the occurrence frequency of Db >=10m was 53%, both being less than those estimated from historical data. but consistent with the observational results from the R/V “Franklin” in the same period and from the Sino-US TOGA program during El Nino period cruises.
(2) Local elements influencing variation of Db were local sea surface wind speed and rainfall. These two elements could be indicated by sea surface buoyancy flux (B). When B was a larger positive (negative) value, due to shallowing (deepening) of the mixed layer, Db became thicker (thinner).
(3) Large scale elements influencing Db variation were sea surface wind field and current state. When steady westerly (easterly) winds blew over the study area and eastward(westward) currents prevailed in the sea surface layer, due to deepening (shallowing) of isothermal layer depth, Db thickens (thins). The inter-annual variation of sea surface wind field, current state and rainfall in the western equatorial Pacific were highly correlated with the ENSO cycle, so the Db variation responded accordingly with the ENSO event. |
Key words: TOGA-COARE, Western equatorial Pacific, Barrier layer |