基于卫星遥感的海浪斜率方差验证与差异原因分析
doi: 10.11728/cjss2026.03.2025-0076 cstr: 32142.14.cjss.2025-0076
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郎姝燕 女, 1983年出生于山西, 硕士研究生学历, 现为国家卫星海洋应用中心研究员, 主要研究方向为海洋遥感. E-mail: langshuyan@mail.nsoas.org.cn -
李秀仲 男, 1985年出生于山东, 博士研究生学历, 现为南京信息工程大学海洋科学学院副教授, 硕士生导师, 主要研究方向为海洋微波遥感. E-mail: lixiuzhong@nuist.edu.cn
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通讯作者:
Validation and Discrepancy Analysis of Sea Surface Mean Square Slope Measured by SWIM and CYGNSS
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摘要: 海面斜率方差MSS(Mean Square Slope)是海洋微波遥感领域表征海面粗糙度的关键参数, 对研究海气耦合过程及海洋气象监测意义重大. 对中法海洋卫星CFOSAT(China France Oceanography Satellite)搭载的海浪波谱仪SWIM(Surface Waves Investigation and Monitoring)和旋风全球卫星导航系统CYGNSS (Cyclone Global Navigation Satellite System)所反演的MSS展开对比分析. SWIM 通过拟合不同入射角和方位角下的二维归一化雷达后向散射截面反演MSS, CYGNSS则在初步观测基础上减去一个校正量以获取局地风引起的MSS. 对2023年1月数据进行时空匹配后进行直接对比, 发现小风速下SWIM反演的MSS大于CYGNSS, 而风速超过约7m·s–1时CYGNSS的MSS大于SWIM反演的MSS, 这主要归因于二者微波波段不同及CYGNSS反演过程中减去涌浪产生的 MSS校正量. 利用Elfouhaily谱模型对SWIM MSS校正后, 二者平均偏差约为0.03, 随机均方误差为0.0323, 此误差源于涌浪产生的MSS及截止波长差异. 研究结果明确了两种星载传感器反演MSS的差异与误差来源, 为MSS数据校准及后续海洋研究与应用提供了重要参考.
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关键词:
- 海面斜率方差 /
- 微波遥感 /
- 中法海洋卫星 /
- SWIM /
- 旋风全球卫星导航系统
Abstract: The Mean Square Slope (MSS) of the sea surface is a key parameter for characterizing sea surface roughness in the field of marine microwave remote sensing, and it is of great significance for studying the air-sea coupling process and marine meteorological monitoring. This paper conducts a comparative analysis of the MSS retrieved by the Surface Waves Investigation and Monitoring (SWIM) on the China-France Oceanography Satellite (CFOSAT) and the Cyclone Global Navigation Satellite System (CYGNSS). SWIM retrieves the MSS by fitting the two-dimensional normalized radar backscatter cross-section under different incident angles and azimuth angles. CYGNSS obtains the MSS caused by local winds by subtracting a correction amount on the basis of preliminary observations. In this paper, after collocating the data from SWIM and CYGNSS in January 2023, a direct comparison has been made. It is found that the MSS derived from SWIM is higher than that retrieved by CYGNSS under low wind speeds, while when the wind speed exceeds approximately 7 m·s–1, the MSS derived from CYGNSS is higher than that given by SWIM. This is mainly attributed to the differences in the microwave bands of the two and the correction amount of the MSS generated by swell subtracted during the retrieval process of CYGNSS. After correcting the SWIM MSS using the Elfouhaily spectrum model, the bias between the two is approximately 0.03, and the random root mean square error is 0.0323. This error is caused by the MSS generated by swell and the differences in the cutoff wavelength. The research results clarify the differences and error sources of the MSS retrieved by the two spaceborne sensors, providing an important reference for the calibration of MSS data and subsequent marine research and applications. -
图 4 SWIM与CYGNSS MSS之差随风速的变化
Figure 4. Dependence of the difference between SWIM and CYGNSS MSS on wind speed
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