摘要
本文在大量调查资料的基础上,分析了1975—1984年南海环境要素的年际变化及其在1982—1983年的表现。研究发现,与正常年份比较,各要素在1982—1983年的表现都比较特殊,沿岸江河径流量猛增;气温、水温、盐度、pH值偏低;海水含氧量偏高,温、盐、密跃层强度增大;南海暖流和黑潮南海分支流轴的平均位置移到调查海区的最南面。作者认为,这一异常现象与1982—1983年赤道太平洋海域发生的强E1 Ni(?)o过程密切相关。
Based on voluminous data from 1975-1984 standard section investigations in the northern South China Sea (SCS), the annual variation of the environmental factors (hydrography, meteorology, chemistry, etc.) in the SCS is analysed and mainly their behaviour during 1982-1983 is discussed. The results showed that during the 10 years, all the factors had significant annual variations with approximately 3-4 year period that was in step with the El Nino oscillating cycles. These environmental factors in 1982-1983 differed from the normal in other years. In particular, the most obvious deviation from normal was that coastal river runoff and oxygen contents in the seawater increased to maximum but that the atmospheric temperature, water temperature, salinity and pH declined to the lowest of the past years. It is considered that the above characteristics were somehow related to the earlier coming of the rainy season, the more than usual rainfall, the obvious increase of the runoffs to the sea in 1983, the strong cold air invading the South China Sea from Dec. 1982 to Jan.-Mar. of 1983 and the strong subtropical High which lead to lower temperature and rainy weather in the northern South China Sea. The frequent intrusion of cold air was certainly the main reason for the lower atmospheric and sea water temperature in the northern South China Sea. The lasting rainy weather increasing river runoff increase sharply resulted in minimum salinity and pH values. The maximum oxygen contents in the seawater were due to the massive input of oxygen-rich river water. Further analysis of the investigation data in the same period indicates that there were two periods of strong thermoclines, haloclines and pycnoclines in the El Nino years of 1976 and 1982. The average position of the flow axis(located near the 500m isobath of the coatinental slope area) of the kuroshio branch in the S. C. S., and the average position (located approximately near the 100m isobath) of the flow axis of the warm current in the S. C. S. moved to the southern most position in 1982. It is notable that these movements in the strong El Nino years of 1982-1983 were similar to the southward movement of the Intertropical Convergence Zone. It is concluded that the strong El Nino in the East pacific was closely related to the abnormalities the environmental factors and their development in the S. C. S. as well as the shift of the flow axis of the warm current and the kuroshio branch in the S. C. S.. This indicates that the E1 Nino not only severely affects the weather and the hydrographic features of the coast region of the East Pacific, but also has a great influence on the weather and climate of our country and the environmental factors of the S. C. S.
出处
《海洋与湖沼》
CAS
CSCD
北大核心
1992年第4期379-386,共8页
Oceanologia Et Limnologia Sinica
基金
自选课题
关键词
南海
环境因素
年际变化
气温
Environmental factors, Annual variation, EI Nino.
