中低纬度海表面温度日变化特征分析

Diurnal variabilities of sea surface temperature in the low-and mid-latitudes

针对海表面温度日变化幅度,基于观测数据,建立经验诊断模型。利用30 a再分析数据计算得到时间跨度为30 a、水平分辨率约为0.3°的DSST逐日数据集,并对DSST时空变化规律进行了分析。分析表明:DSST空间变化明显,北半球的平均DSST高于南半球。DSST具有明显的季节变化,西太平洋暖池区域在秋季DSST值域较大,东太平洋则四季均具有较大的DSST;热带大西洋全年整体DSST变化不明显;印度洋由于受季风影响,阿拉伯海和孟加拉湾的DSST值域夏季小于冬季。太阳短波辐射和风速因素是造成上述特征的主要原因。DSST 30 a的异常值长期变化不大,但年际振荡明显,整体年际变化异常趋势存在下降趋势。DSST与ENSO事件具有较好的相关性。

Aiming at the sea surface temperature diurnal amplitude（DSST）, this study develops an empirical diagnosis model based on the observation data. Based on the 30 a reanalysis data, the DSST data set with a horizontal resolution 0.3°×0.3° is established. The temporal and spatial variation characteristics of DSST at the middle and low latitude are analyzed. The results show that the spatial variation is obvious, with a higher DSST value in the northern hemisphere and a lower DSST value in the southern hemisphere. The DSST has obvious seasonal variation. DSST value in the warm pool area of Western Pacific is higher in autumn, and in the eastern Pacific is high in four seasons. In the tropical Atlantic sea DSST value changes without obvious characteristic.Influenced by monsoon, the DSST value in the Arabian Sea and the Bay of Bengal is lower in summer compared to that in winter. The solar shortwave radiation and wind speed are the main reasons for the above characteristics.DSST anomaly over the past 30 years doesn＇t change obviously, while the interannual variation is obvious. The overall abnormal tendency of the interannual variation has downward trend, and the values have a certain correlation with Nino 3.4 index.