基于多波束激光测高卫星ICESat-2观测的垂线偏差解算

Deflections of the vertical determination based on multi-beam laser altimetry satellite ICESat-2 data

卫星测高技术中,传统的微波雷达海洋测高卫星轨道倾角近90°,且只能利用沿轨海面高数据计算垂线偏差,导致其解算垂线偏差卯酉分量比子午分量精度差。ICESat-2搭载的ATLAS系统可同时发射6条激光波束测量海面高,有望通过计算跨轨垂线偏差来提高卯酉分量精度。本研究以中国南海(0°N~30°N,105°E~125°E)为研究区域,基于ICESat-2海面高产品ATL12计算沿轨垂线偏差和跨轨垂线偏差,并利用最小二乘配置法反演1′×1′规则网格垂线偏差。实验结果表明:ICESat-2沿轨海面高数据解算的子午分量和卯酉分量与XGM2019e_2159-DOV模型的验证精度分别为0.90″和1.91″,子午分量精度明显高于卯酉分量。而跨轨海面高数据解算的子午分量和卯酉分量与XGM2019e_2159-DOV模型的验证精度分别为2.63″和1.66″,卯酉分量精度明显提高且高于子午分量。

In satellite altimetry,the traditional microwave radar ocean altimeter satellite has an orbital inclination of nearly 90°and only along-track deflection of vertical can be calculated by using along-track sea surface height data,resulting in the lower precision of the prime vertical component than that of the meridian component.ICESat-2 is equipped with an ATLAS system that can simultaneously transmit six laser beams to measure the sea surface height,which is expected to improve the precision of the prime vertical component by calculating the cross-track deflection of the vertical.In this paper,ICESat-2’s sea surface height product,ATL12,was used to calculate the along-track deflection of the vertical and cross-track deflection of vertical in the South China Sea(0°N~30°N,105°E~125°E).The 1′×1′gridded deflection of the vertical was inverted by using the least-squares collocation method.The results show that the meridian and prime vertical components calculated by the along-track sea surface height data are verified by XGM2019e_2159-DOV model with the precision of 0.90″and 1.91″respectively.The precision of the meridian component is significantly higher than that of the prime vertical component.The meridional and prime vertical components calculated by cross-track sea surface height data are verified by XGM2019e_2159-DOV model with the precision of 2.63″and 1.66″,respectively.The precision of the prime vertical component is improved and higher than that of the meridian component.