星载单光子激光雷达海面回波信号模型

Model of Sea Surface Echos from Spaceborne Single Photon Lidar

过去几十年中激光雷达的发展对于海洋监测有着重大意义,而星载单光子激光雷达以更高的分辨率和测量精度展现了其在海洋遥感中的优势地位。结合单光子探测器的响应特性,依据海面反射模型,提出了一个定量计算海面回波信号强度的理论模型。使用ICESat-2(The Ice, Cloud, and land Elevation Satellite 2)对地观测激光测高卫星搭载的先进地形激光测高系统(ATLAS)的参数作为输入,采用ICESat-2获取的ATL03数据统计回波信号强度和全球风场数据验证模型,模型在菲律宾海域统计的多轨数据较好,在海面风速为4~10 m/s的情况下,其均值误差为0.0037个光子/脉冲,均方根误差为0.153个光子/脉冲。分析得出了星载单光子海洋测高仪回波强度和海平面上方平均风速的关系,该结论对海平面上方风速反演提供了重要的理论依据。

Over the past few decades, the development of lidars has great significance for ocean monitoring. The spaceborne single photon lidar shows its advantage in marine remote sensing because of high resolution and precision. In this paper, based on the response characteristics of single photon detectors and the sea surface reflection model, a theoretical model for quantitatively calculating the intensity of sea surface returns was proposed. Inputting the system parameters of the advanced topographic laser altimeter system(ATLAS) carried by ICESat-2(the Ice, Cloud, and land Elevation Satellite 2), we verified the model with the echo intensity based on the measured point cloud data ATL03 from ICESat-2 and the global wind field data. The results show that this model performs well according to many tracks’ data above the Philippine Sea. When the sea surface wind speed is in the range of 4--10 m/s, the mean error is 0.0037 count/pulse, and the root mean square error is 0.153 count/pulse. The relationship between the echo intensity of the spaceborne single-photon ocean altimeter and the average wind speed above the sea level was analyzed. The conclusion provides an important theoretical basis for the wind speed inversion above the sea level.