基于卫星测高与卫星测温的表层流产品生成方法应用评估

提高海洋表层流的精度与分辨率对于相关应用领域至关重要。研究引入海表面温度(sea surface temperature,SST)信息对高度计导出流场的改进效果,计算了2018年每日无间隔的全球海洋表层流速度。通过增加热量守恒方程约束,引入卫星测温产品,在地转流基础上生成表层流产品,并与现场漂流浮标速度比较,评估了使用多源卫星遥感获取海流的质量。研究表明,本文方法在不改变沿等温线的切向流速分量的前提下,沿等温线的法向流速分量得到了改进,方法能充分利用海表温度信息提取流场特征信息;方法不适用于海表面温度梯度较小区域,在梯度较大区域可获得明显改进;优化流场能更好地刻画海面海流变化,证明结合卫星测高与卫星测温可改善海洋表层流动;存在强烈中尺度活动和热梯度区域,增加SST观测能够弥补测高资料的不足。

APPLICATION EVALUATION OF SURFACE CURRENTS PRODUCT GENERATION METHOD BASED ON SATELLITE ALTIMETRY AND SATELLITE TEMPERATURE MEASUREMENT

Improving the accuracy and resolution of ocean surface currents is crucial for related applications. By introducing sea surface temperature (SST) data, the calculation of current field derived from altimeter data could be improved, which was validated by the calculation of the daily gapless global ocean surface current velocities in 2018. By adding constraints of the heat conservation equation, introducing satellite temperature measurement products, generating surface current products on the basis of geostrophic current, and comparing with the in-situ drifting buoy velocities, the quality of currents obtained by multi-source satellite remote sensing was evaluated. The method does not change the tangential velocity component along the isotherm, and the normal velocity component along the isotherm can be improved. The method makes full use of the sea surface temperature information to extract the flow field characteristic information. In addition, the method worked well with significant improvement for regions in strong SST gradient, but not for those in low SST gradient. The optimized current field can better describe the change of sea surface current, proving that the combination of satellite altimetry and satellite temperature measurement can improve the surface flow of the ocean. In the areas with strong mesoscale activities and thermal gradients, increasing SST observations is the ideal way to compensate the lack of altimetry data.