热带大西洋海温梯度的季节变化趋势研究

A Study on the Seasonal Variation Trend of the Tropical Atlantic SST Gradient

摘要: 本文利用英国哈德莱气候预测研究中心提供的HadISST海表温度资料，通过滑动平均，Theil-Sen无参趋势计算方法，首先分析了热带大西洋海表温度的年平均，季节平均及其季节变化趋势。然后再通过对热带大西洋东西海域分别进行区域平均，分析其各自的时间序列和季节变化趋势，最后对热带大西洋东西海温梯度的季节特征及长期趋势进行探究。研究结果表明：1) 从纬向上看，热带大西洋年平均海温总体由低纬向高纬递减；从经向上看，同纬度西部海域温度要高于东部海域。海温距平总体上由低纬向高纬递增，由东至西递减；春季和冬季，在赤道及赤道以南以正距平为主，赤道以北以负距平为主；夏季和秋季的距平分布则刚好相反。2) 春季，热带大西洋海温在赤道以南呈上升趋势，赤道以北呈下降趋势；秋季海温的南北趋势则刚好相反；夏季，海温在0˚N~15˚N范围内呈上升趋势，15˚N以北呈下降趋势，赤道以南，西岸呈上升趋势，东岸呈下降趋势；冬季，海温总体呈下降趋势。3) 春季，热带东大西洋海温呈上升趋势，西大西洋呈下降趋势；夏季和秋季，热带东西大西洋海温均呈上升趋势；冬季，热带东西大西洋海温均呈下降趋势；4) 春季和冬季，热带西大西洋海温要低于东大西洋，夏季和秋季则相反。春季和冬季，海温梯度呈递减趋势，夏季和秋季呈递增趋势。

Abstract: In order to study the seasonal characteristics and trends of the SST gradient in the tropical Atlantic, this paper uses the data of SST (HadISST) from the Hadley Center in the UK. Based on the method of moving average and Theil-Sen parameterless trend calculation, this paper first analyzes the annual average, seasonal average and seasonal trend of the SST in the tropical Atlantic. Then, the regional averages of the eastern and western tropical Atlantic are analyzed to research their respective time series and seasonal trends. At last, the seasonal characteristics of east-west SSTA gradients and long-term trends of the tropical Atlantic are analyzed. The research results show that: 1) From the latitude upward, the annual average SST in the tropical Atlantic generally shows a decreasing trend from low latitude to high latitude. From the perspective of the longitude, in the equatorial Atlantic Ocean, the SST in the western sea area is higher than that in the eastern sea area at the same latitude. SSTA generally increases from low latitudes to high latitudes, and decreases from east to west. In spring and winter, the SSTA in the tropical Atlantic is mainly positive near the equator and in the south of the equator, but negative in the north of the equator. Summer and autumn are just the op-posite. 2) In spring, the SSTA in the tropical Atlantic increases yearly in the south of the equator, but opposite in the north of the equator, the north-south trend of the autumn SSTA is just the opposite. In summer, the SSTA shows an upward trend in the range of 0˚N~15˚N , the north of 15˚N shows a downward trend, and the south of the equator, SSTA on the west coast is increasing, while on the east coast is decreasing. In winter, the SSTA in the equatorial Atlantic generally declines. 3) In spring, the SST is increasing in the tropical east Atlantic and decreasing in the tropical west Atlantic. In summer and autumn, the SSTA in the tropical east and west Atlantic Ocean both shows an increasing trend. In winter, the SSTA in the tropical east and west Atlantic Ocean shows a decreasing trend. 4) In spring and winter, the SSTA in the tropical western Atlantic is lower than in the eastern Atlantic, while the opposite is true in summer and autumn. The SSTA gradient in spring and winter decreases yearly, and in summer and autumn, it shows an increasing trend.