基于遥感资料的夏季广东沿岸上升流分布特征

【目的】研究广东沿岸夏季上升流的时空变化规律及其对沿岸区域气候的影响。【方法】采用Sobel梯度算法,综合MODIS海表温度和QuikSCAT海面风场资料对2003年夏季广东沿海上升流的范围、强度、持续时间等时空分布特征进行综合分析。【结果】广东沿岸海域存在明显的上升流现象,整体呈现强弱强的特征,在7月初出现具有明显上升流特征的低温表层水,至7月底低温水活动减弱至最低,于8月初又存在一个增强的过程;同时,上升流并非始终稳定存在。【结论】对比海表温度数据和风场资料可以发现,上升流的强度、持续时间等与风场的变化存在密切联系,风场是上升流的一个重要影响因素,此外,沿岸水团的分布也是影响广东沿岸上升流空间分布的重要因素。

Characteristics of the Distribution of Upwelling Flow off Guangdong Coast in Summer Based on Remote Sensing Dataset

[Objective] The upwelling off Guangdong coast was studied in order to understand the characteristics of its spatial and temporal distributions, as well as its influence on the coastal regional climate.[Methods] Based on the MODIS sea surface temperature(hereafter, SST) data and sea surface wind of QuikSCA, the upwelling off Guangdong coast was surveyed in the summer of 2003. The characteristics of spatial and temporal distributions, including the range, the intensity, and the duration, have been comprehensively analyzed using the Sobel gradient algorithm.[Results] The upwelling phenomena were obvious off Guangdong coast, which changed overall from stronger to weaker and then to stronger again.The low surface waters with clear upwelling appeared in early July, decreased to the lowest in late July, and increased again in early August.Meanwhile the upwelling phenomena did not always stably exist.[Conclusion] Comparison of SST with wind field suggested that the intensity and duration of upwelling were closely associated with wind variations.The wind field was one of the main factors affecting the upwelling.Furthermore, the distribution of water mass off Guangdong coast had an important influence on the spatial distributions of upwelling.