基于IPCC预测结果的北太平洋海表面温度变化分析

Variation of sea surface temperature in the North Pacific based on different IPCC scenarios

利用IPCC-AR4气候模式诊断与比较计划(PCMDI)20C3M试验和A1B情景试验模拟数据,研究了在温室气体排放情景下,北太平洋海表面温度的变化及其对太平洋风应力旋度变化的响应。结果表明,温室气体中等排放A1B情景与20C3M情景相比,北太平洋年平均海表面温度表现为一致增温的趋势,且最大的增温中心位于黑潮及其延伸体区。与20C3M试验相比,CO2增加情景下北太平洋中部东风加强,增加向北的Ekman输送,使得北太平洋内区增温。风应力旋度零线也向北略有移动,导致黑潮延伸体向北移动并得到加强,从而引起延伸体区较强增温。风应力旋度零线的纬度附近产生的Rossby波,向西传播到黑潮延伸体区,进一步加强黑潮延伸体区的温度异常。海洋对北太平洋风应力场变化的局地响应及延迟响应,使黑潮延伸体海域海表面增温远大于周围海区。

Using the multimodel datasets of 20C3M and the SRESA1B scenario projection from Program for Climate Model Diagnosis and Intercomparison for IPCC-AR4 ,we have investigated the sea surface temperature （SST） changes in the North Pacific and its response to wind stress changes in the North Pacific under different atmospheric greenhouse gases scenarios. The analysis shows that the SST will increase in most parts of the North Pacific as a result of the effect of higher atmospheric CO2 concentration, with the maximum increasing center located along the Kuroshio Extension region. We conclude that the warming in the SRESAIB scenario over the North Pacific espe- cially along the Kuroshio Extension might be attributable to the stronger easterlies prevail in the central Pacific and poleward shift of the zero wind stress curl line. This Ekman response is local and fast. On the other hand, because the zero wind stress curl line displaced to higher latitudes,it generates stronger Kuroshio and its extention. It also generates anomalous Rossby waves at the latitude of zero wind stress curl line which propagate to the west. The Rossby waves change the thermocline in the Kuroshio Extension region and eventually warm the SST. The changes of wind stress in the interior North Pacific eventually generate SST warm anomalies in the Kuroshio Extension region several years later.