中文摘要：

利用新的SODA海表温废资料，研究了2002～2007年南海表层水温（SST）的均方差特征，探讨其对声速变化的影响。分析结果表明：在所选取的南海海域中，南海SST均方差随季节和纬度都有所变化，整个南海SST均方差值变化范围为1—6。1～3月高于18°N海域，海温年际变化较大，基本接近4．低于18°N海域均方差值随月份减弱；4～6月南海海域海温年际变化小，随月份和纬度增大而略微增大；7~9月海温变化不明显，基本保持同样的变化趋势；10～12月在高于12°N附近海域，海温均方差值先变小，到12月份又开始增大，低于120N附近海域，均方差值保持在1左右变化。南海海表声速较大，但随季节变化不明显，夏、秋两季比春、冬两季较高。

英文摘要：

Using the sea surface temperature （SST） of the new Simple Ocean Data Assimilation （SODA） data during 2002-2007, monthly mean square deviation in the South China Sea is analyzed and the effect on sound speed is discussed. The results show that in the South China Sea, with the changing of the season and the latitude, the mean square deviation changes too, and its variation range is 1 to 6. The SST interannual variability above 18°N sea changes largely from January to March, and its variation range is about 4, the mean square deviation decreases with the increase of month in the latitude under 18°N; the interannual variability changes lesser from April to June; the SST changes a little from July to September, and they also have the same variation trend; above 12°N sea, the SST decreases in November, and then increases in December, the SST mean square deviation is not monotonously under the 12°N sea. The sound speed in the South China Sea is high, and its variation is not monotonously with the season changing.