热带海表风速与海表温度日变化关系分析

摘要

利用热带测雨卫星（TRMM）搭载的微波成像仪（TMI）探测结果，在像元分辨率上同步反演的10年海表温度（SST）和海表风速（SSW）资料，研究了热带地区非降水条件下 SSW变化对 SST 日变化的影响。结果表明热带地区SST日变化显著，SST日最小值多出现在早晨03：00（当地时间，下同）至06：00，日最大值多出现在午后17：00至19：00，SST日绝对振幅为1.9～3.4°C，日相对振幅为5%～7%。SSW变化对SST日最小值和日最大值的出现时间及SST日振幅均有明显的影响，且均呈现出区域性差异。热带地区SST日绝对振幅随SSW增大而减小，当SSW增加至9 m/s之后，SST日绝对振幅变化不再明显；二者符合特定的正弦函数关系。在风速小的情况下，暖池区域平均SST日绝对振幅异常减小了0.16°C；在风速大的情况下，秘鲁沿岸区域平均SST日绝对振幅异常增大了0.17°C，且SST随时间变化波动较大。上述研究结果为下一步研究海表感热和潜热日变化打下了基础。%Based on sea surface temperature (SST) and sea surface wind speed (SSW) data retrieval from the tropical rainfall measuring mission (TRMM) microwave imager (TMI) from 1998 to 2007, the authors investigated the features of diurnal variation of SST under the influence of SSW in the tropics under non-precipitation conditions. The retrieved SST and SSW data were matched at TMI resolution within the TMI orbit swath. The results suggest a notable diurnal variation of SST over the topical ocean. The minimum value of the diurnal cycle of SST appears during 0300 LST to 0600 LST and the maximum occurred during 1700 LST to 1900 LST. The diurnal absolute amplitude of SST is about 1.9-3.4 °C, and the relative amplitude is about 5%-7%. The effect of SSW on the diurnal SST amplitude is significant and shows the regional characteristics, just as it influences the time of the minimum/maximum value. The diurnal SST amplitude decreases with an increase of the SSW, but it changes only slightly with increasing SSW when the SSW is greater than 9 m/s. Statistical analysis shows a significant sinusoidal correlation between the diurnal SST amplitude and SSW. In particular, reduced SSW leads to a decrease of 0.16 °C in the diurnal SST amplitude in the western equatorial Pacific, whereas enhanced SSW leads to an increase of 0.17 °C in the diurnal SST amplitude over the coastal area of Peru. The above results provide a basis for further research on diurnal variations of latent and sensible heat fluxes.