使用QuikSCAT月平均数据研究南海及邻近海域海面风场季节性变化的空间差异。矢量经验正交函数分析方法的结果表明, 受季风影响该海域海面风场以季节性变化为主, 包括年循环和半年周期循环, 并且季风对各区域的影响强度也有所不同。通过计算各网格点风速时间序列的方差及季节性循环所占的比例可以得知, 纬向风和经向风方差的空间分布形式不同, 最大值分别发生在长山山脉以南和以东海面; 与经向风相比, 纬向风年周期循环所占的比例从南到北空间变化很大, 从80%下降到10%, 而在东海南部海域则以半年周期变化为主。选取5个代表性区域进行比较, 可见海面风年变化形式也具有明显的空间差异。
Monthly Quick Scatterometer (QuikSCAT) wind data are employed to study the spatial patterns in seasonal variability of sea surface wind over the South China Sea and its adjacent ocean. The results of vector empirical orthogonal function method indicate that the sea surface wind is dominated by seasonal variability due to the monsoon, including the annual cycle and the semi-annual cycle. In addition, the impact of monsoon differs spatially. Variance of zonal or meridional wind exhibits different spatial pattern, with the maximum value to the south and east of Annam Cordillera, respectively. In contrast to the meridional wind, the zonal wind shows a large spatial variation, with its annual cycle variance decreasing from 80% in the south to 10% in the north and the semi-annual cycle dominating the southern part of the East China Sea. Five representative sea areas are chosen to compare with each other; these results show that the form of annual variation also experiences pronounced spatial dependence.
[1] 杨亮. 基于遥感数据的西北太平洋海面风场时空特征分析[D]. 青岛: 国家海洋局第一海洋研究所, 2007: 1.
[2] 谢强, 王东晓, 王卫强, 等. 南海几种海面风应力资料的比较分析[J]. 热带海洋学报, 2001, 20(1): 91-100.
[3] CHELTON D B, SCHLAX M G, FREILICH M H, et al. Satellite measurements reveal persistent small-scale features in ocean winds[J]. Science, 2004, 303: 978-983.
[4] LIU W T, XIE XIAOSU. Space-based observations of the seasonal changes of South Asian monsoons and oceanic response[J]. Geophys Res Lett, 1999, 26(10): 1473-1476.
[5] 王东晓, 周发琇, 李永平. 南海表层水温和海面热收支的年循环特征[J]. 海洋学报, 1997, 19(3): 33-44.
[6] 周发琇, 高荣珍, 张涛. 南海表层水温年循环的谐波特征[J]. 青岛海洋大学学报, 1999, 29(2): 173-179.
[7] 高荣珍, 王东晓, 王卫强, 等. 南海上层海洋热结构的年循环与半年循环[J]. 大气科学, 2003, 27(3): 345-353.
[8] HU JIANYU, KAWAMURA HIROSHI, HONG HUASHENG, et al. A review on the currents in the South China Sea: seasonal circulation, South China Sea warm current and Kuroshio intrusion[J]. J Oceanogr, 2000, 56: 607-624.
[9] 程旭华, 齐义泉, 王卫强. 南海中尺度涡的季节和年际变化特征分析[J]. 热带海洋学报, 2005, 24(4): 51-59.
[10] 齐义泉, 施平, 毛庆文. 南海海面风速季节特征的卫星遥感分析[J]. 热带海洋, 1996, 15(1): 68-73.
[11] 刘春霞, 何溪澄. QuikSCAT散射计矢量风统计特征及南海大风遥感分析[J]. 热带气象学报, 2003, 19(增刊): 107- 117.
[12] 郭小钢, 靖春生, 李立. 南沙群岛海域风场特征-卫星散射计观测资料分析[J]. 热带海洋学报, 2003, 22(4): 18-25.
[13] VON AHN J M, SIENKIEWICZ J M, CHANG P S. Operational impact of QuikSCAT winds at the NOAA Ocean Prediction Center[J]. Weather Forecasting, 2006, 21: 523-539.
[14] PAN JIAYI, YAN XIAOHAI, ZHENG QUANAN, et al. Interpretation of scatterometer ocean surface wind vector EOFs over the Northwestern Pacific[J]. Rem Sen Envir, 2002, 84: 53-68.
[15] 赵喜喜, 候一筠, 齐鹏. 中国海海面风场时空变化特征分析[J]. 高技术通讯, 2007, 17(5): 523-528.
[16] FANG GUOHONG, CHEN HAIYING, WEI ZEXUN, et al. Trends and interannual variability of the South China Sea surface winds, surface height, and surface temperature in the recent decade[J]. J Geophys Res, 2006, 111: C11S16. doi: 10.1029/2005JC003276.
[17] TORRENCE C, COMPO G P. A practical guide to wavelet analysis[J]. Bull Amer Meteor Soc, 1998, 79(1): 61-78.
[18] LEGAARD K R, THOMAS A C. Spatial patterns in seasonal and interannual variability of chlorophyll and sea surface temperature in the California Current[J]. J Geophys Res, 2006, 111: C06032. doi: 10.1029/2005JC003282.
[19] ACCADIA C, ZECCHETTO S, LAVAGNINI A, et al. Comparison of 10-m wind forecasts from a regional area model and QuikSCAT scatterometer wind observations over the Mediterranean Sea[J]. Mon Wea Rev, 2007, 135: 1945-1960.
[20] NORTH G R, BELL T L, CAHALAN R F, et al. Sampling errors in the estimation of empirical orthogonal functions[J]. Mon Wea Rev, 1982, 110: 699-706.
[21] 齐义泉, 施平, 毛庆文, 等. 基于T/P资料分析南海海面风、浪场特征及其关系[J]. 水动力学研究与进展, 2003, 18(5): 619-624.
[22] XIE SHANG-PING, XIE QIANG, WANG DONGXIAO, et al. Summer upwelling in the South China Sea and its role in regional climate variations[J]. J Geophys Res, 2003, 108(C8): 3261. doi: 10.1029/2003JC001867.
