Quality Evaluation of Sea Level Height Data of HY-2C Satellite
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摘要: 卫星海面高度数据对于监测全球海面高度具有重要的意义,所以卫星高度数据的定标和检验变得至关重要。海洋二号C(HY-2C)卫星是继海洋二号B卫星的第二颗业务卫星于2020年成功发射升空。然而,目前对HY-2C卫星高度计的数据质量了解甚少,所以对HY-2C卫星的海面高度数据进行质量分析具有重要的意义。本文以同期观测的HY-2B卫星和Jason-3卫星的地球物理数据(GDR)为参考,对HY-2C卫星遥感地球物理数据(SGDR)的海面高度进行数据质量分析。结果显示:在星星交叉定标中使用三种常见的交叉定标插值方法对HY-2C卫星的海面高度异常数据进行自交叉点分析时,HY-2C卫星海面高度异常数据质量分析的结果不同。其中使用三次样条插值方法质量分析的结果最优,得到海平面高度异常差的平均值是0.03 cm,标准差6.17 cm。此外,对HY-2C卫星和HY-2B卫星互交叉点海面高度异常差异的平均值是-0.47 cm,标准差是5.32 cm;HY-2C卫星SGDR产品与Jason-3卫星GDR产品的海面高度异常数据进行互交叉点分析,得到海平面高度异常差的平均值是-0.3 cm,标准差是5.32 cm;这些数据表明HY-2C卫星的测高精度与HY-2B卫星、Jason-3卫星一致。因此HY-2C高度计产品数据质量稳定,能满足海洋应用和科学研究的需要。Abstract: As an important part of monitoring oceanic phenomenon, it is essential to calibrate altimeter sea level height data. In 2020, the Haiyang-2C (HY-2C) satellite altimeter was sent to orbit as a follow-up mission of the HY-2B satellite altimeter. However, the quality of HY-2C sea level height is not fully known yet. In this paper, the quality and accuracy of HY-2C Sensor Geophysical Data Records (SGDR) of the latest version were assessed through the comparison with the HY-2B Geophysical Data Records (GDR) data and Jason-3 GDR data measured at the same time. According to the results: Self-crossover points analysis is carried out by Star cross calibration of HY-2C satellite. The quality analysis results of Sea level anomaly data of HY-2C SGDR data are different. Through the comparison results, the optimal cubic spline interpolation method has the best quality analysis performance, with mean value is 0.03 cm and the standard deviation is 6.17 cm. The mean and standard deviation of Sea level anomaly at the dual-crossing calibration of HY-2C and HY-2B satellites are -0.47 cm and 5.32 cm. The mean and standard deviation of Sea level anomaly at the intersection of HY-2C and Jason-3 satellites are -0.3 cm and 5.32 cm. These results show that HY-2C has the same precision as HY-2B satellite and Jason-3 satellite. Data quality of HY-2C satellite is enough to meet the requirements of marine scientific research and application.
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Key words:
- HY-2C /
- Radar altimeter /
- Sea Level Height /
- Crossover analysis
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表 1 HY-2C和HY-2B、Jason-3卫星高度计和辐射计数据编辑的参数阈值
Tab. 1 Main editing thresholds values of HY-2C、HY-2B、Jason-3 satellite altimeter and microwave radiometer
观测量 最小值 最大值 20 Hz测距数目 10 − 20 Hz测距标准差/mm 0 200 轨道高度-测距值/mm −130 000 100 000 模型干对流层校正/mm −2 500 −1 900 辐射计湿对流层校正/mm −500 −1 Ku波段电离层校正/mm −400 40 Ku波段海况偏差/mm −500 0 潮汐校正/mm −5 000 5 000 固体潮校正/mm −1 000 1 000 极潮校正/mm −150 150 Ku波段有效波高/mm 0 11 000 Ku波段向后散射系数/db 7 30 风速/(m·s−1) −0 30 Ku波段偏指向角平方/(°)2 −0.2 0.64 后向散射系数标准差/db − 1 后向散射系数观测数 10 − 表 2 HY-2C卫星自交叉点海面高度异常数据精度的比较
Tab. 2 Comparison of accuracy in HY-2C self-crossover SLA data
临近点插值 选取最近点 三次样条插值 交叉点数量(SLA<20 cm) 14 746 14 699 14 312 mean 0.03 cm 0.03 cm 0.03 cm std 6.63 cm 6.89 cm 6.17 cm 表 3 HY-2B卫星自交叉点海面高度异常数据精度的比较
Tab. 3 Comparison of accuracy in HY-2B self-crossover SLA data
临近点插值 选取最近点 三次样条插值 交叉点数量(SLA<20 cm) 5 005 5 045 4 936 mean 0.01 cm 0 cm 0.01 cm std 4.60 cm 5.1 cm 4.21 cm 表 4 Jason-3卫星自交叉点海面高度异常数据精度的比较
Tab. 4 Comparison of accuracy in Jason-3 self-crossover SLA data.
临近点插值 选取最近点 三次样条插值 交叉点数量(SLA<20 cm) 22 639 22 610 22 233 mean −0.01 cm −0.01 cm 0 cm std 6.63 cm 5.45 cm 4.70 cm 表 5 HY-2C卫星和HY-2B卫星、Jason-3卫星互交叉点海面高度异常数据精度的比较
Tab. 5 Comparison of accuracy in HY-2C and HY-2B, HY-2C and Jason-3 cross-crossover SLA data
HY-2C和HY-2B HY2C和Jason-3 交叉点数(SLA<20 cm) 15 470 15 799 mean −0.47 cm −0.3 cm std 5.32 cm 5.32 cm -
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