摘要:
利用2002-2011年南海海面风场、高度场和温度场的月平均资料分析了这些要素的变化趋势及年际变化特征.计算得到区域平均海面风东分量的线性趋势为(-0.012±0.014) (m·s-1)·a-1,北分量的线性趋势为(-0.014±0.019) (m·s-1)·a-1,其年际变化与NIN~O3指数相关系数可达0.63,滞后1个月;区域平均海面风应力旋度的线性趋势为(0.099±0.330)×10-9 (N·m-3)·a-1,其年际变化与中太平洋厄尔尼诺(EMI)指数呈高度相关,达到-0.85,滞后3个月;区域平均海面高度的线性趋势为(0.665±0.200) cm·a-1,其年际变化与EMI指数相关系数可达-0.80,滞后2个月;区域平均海表温度的线性趋势为(-0.016±0.017) °C·a-1,其年际变化与NIN~O3指数相关系数可达0.68,滞后4个月.其中海表温度的负趋势与近期全球变暖的停滞相一致.采用经验正交函数分解方法分析了各要素的年际变化特征,结果显示海面风场的第一模态呈现海盆尺度的反气旋格局,其对应的时间序列与NIN~O3.4指数相关系数最大可达0.68,滞后5个月.海面高度场的第一模态沿南海东边界和越南东部出现较高值,其对应的时间序列的变化滞后于EMI指数3个月,呈负相关,但系数最大为-0.32.海面温度场的第一模态呈西高东低的分布状态,其对应的时间序列与NIN~O3指数的相关系数最大可达0.62,滞后4个月.%The monthly products of the surface winds (SW),sea surface height (SSH) and sea surface temperature (SST) of the South China Sea (SCS) from satellite observations during 2002-2011 are used to analyze trends and interannual variability.Time series are smoothed with a 12-month running mean filter.The linear trends of the east and north components of the regional mean SW,wind stress curl,SSH and SST are (-0.012±0.014) m/(s·a),(-0.014±0.019) m/(s·a),(0.099±0.33)×10-9 N/(m3·a),(0.665±0.200) cm/a,(-0.016±0.017s) °C/a,respectively.The interannual variability of regional mean SW,wind stress curl,SSH and SST correlates with NIN~O3,EMI (El Ni(n)o Modoki Index),EMI and NIN~O3 with coefficient of about 0.6,-0.85,-0.80 and 0.68,and with lag of 1,3,2 and 4 months,respectively.The negative warming rate of the SCS SST is consistent with the global warming hiatus since the end of the last century.Empirical Orthogonal Function (EOF) analysis shows that the first EOF of the SW is characterized by a basin-wide anticyclonic pattern.The corresponding time coefficient function (TCF) correlates with the NIN~O3.4 index at the 99% confidence level (correlation coefficient=0.68),with a lag of 5 months.The first EOF of the SSH is characterized by high sea level along the east boundary and east of Vietnam.The corresponding TCF correlates with the EMI with a coefficient of-0.32 and a lag of 3 month.The first EOF of the SST is characterized by high values in the west and low values in the east.The corresponding TCF correlates with NIN~O3 index at 99% confidence level (correlation coefficient=0.63),with a lag of 4 months.