摘要
利用高分辨率的海温分析资料模式资料,分析了黑潮暖舌与我国气温的关系,初步探讨了太平洋年代际振荡(PDO)等造成黑潮暖舌变化的可能原因。结果表明,冬季和春季东海黑潮暖舌存在明显的年际和年代际变化。暖舌在1996/1997年发生了一次突变,此前暖舌处在偏冷的状态,之后转为偏暖的状态。我国冬季和春季气温存在一定的年代际变化,1997年之后,冬季除东北和新疆外,气温有所偏高,而春季气温全国表现为一致的显著偏高。冬季和春季气温对黑潮暖舌存在邻(域)响应。冬季东海黑潮暖舌指数与冬季我国东部气温存在正相关,并且这一相关性能够延续到次年春季。冬季黑潮暖舌指数与我国4月海陆热力差异指数也存在显著的正相关。当冬季暖舌偏强(弱)时,4月海陆热力差异指数偏高(低),即东亚地区海陆热力差异偏大(小)。春季黑潮暖舌指数与春季我国中部及南方地区气温也存在正相关,当春季黑潮暖舌偏强(弱)时,上述地区气温将偏高(低)。PDO和黑潮暖舌之间的相互作用存在一个反馈机制。西风的增强,可通过使海洋向大气释放热量增加和向南的埃克曼(Ekman)输送,降低北太平洋中部的SST,而这一地区SST的降低对应着PDO的暖位相。增强的负风应力旋度在北太平洋副热带流涡中强迫出的向南斯维尔德鲁普(Sverdrup)流也偏强,而向北流动的东海黑潮的增强正是补偿了这一向南的海流。黑潮增强后经过两个月将大量热量输送至北太平洋中部,增强了这一地区的SST,而这对应着PDO的冷位相。
Based on the high-resolution analysis data and the sea surface temperature derived from LASG/IAP（State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics/Chinese Academy of Sciences） Climate systems Ocean Model 2.0（LICOM2.0）, the relationship between the Kuroshio warm tongue in the East China Sea and temperature in China is analyzed using correlation and composite analysis methods. Possible reasons for the Kuroshio warm tongue changes are discussed. The results show that the interannual and interdecadal variations in the warm tongue during the winter and spring are significant. There was an abrupt change from cold to warm in the warm tongue in the winter of 1996. Besides, the warm tongue underwent a similar abrupt change in the spring of 1997, when it changed from cold to warm as well. Accordingly, the variability of temperature in winter and the following spring on the time scales from interannual to interdecadal has been detected in China. Temperature in winter after 1997 was higher compared with that before 1997, and the temperature increase is more significant in spring than in winter. In this paper, the border zone response of East-Asia circulation and climate to the SSTA in the Kuroshio region is mainly reflected in the positive correlation between the index of Kuroshio warm tongue（IKWT） and temperature in East China in winter. The high correlation can maintain until the following spring. The significant positive correlation can also be detected between the IKWT and the index of land-sea thermal difference（ILSTD） in April. When the warm tongue is strong（weak） in winter, the ILSTD is high（low）. The positive correlation between the IKWT and temperature can be found in the central and southern regions of China in spring as well. When the springtime warm tongue is strong（weak）, the temperature is high（low） in these regions. There is possibly a feedback mechanism for the interaction between PDO（Pacific Decadal Oscillation） and the warm tongue. The enhancement of the westerly winds can lead to decreases in the SST in the central Pacific by increasing the heat release from the ocean to the atmosphere and displacing isotherms southwestward by Ekman drift. The central Pacific cooling corresponds to a PDO warm phase. Enhanced negative wind-stress-curl forces stronger southward Sverdrup flow in the subtropical North Pacific gyre, which is compensated by a stronger Kuroshio in the East China Sea. Two months later, the heat carried by the Kuroshio arrives in the central North Pacific, leading to increases in SST in this region. This period corresponds to a cold PDO phase.
出处
《气候与环境研究》
CSCD
北大核心
2016年第3期333-345,共13页
Climatic and Environmental Research
基金
国家重点基础研究发展计划(973计划)项目2013CB956200
国家自然科学基金项目41490642
41375069~~
