全球导航卫星系统反射测量技术 (GNSS-R) 凭借其低成本、信号穿透性强、全天候观测等优势, 在海面风速反演领域展现出巨大潜力。然而, 由于CYGNSS卫星的覆盖范围有限, 当前星载GNSS-R研究主要集中于低纬度区域, 缺乏对GNSS-R风速反演在全球范围内适用性的系统验证。为此, 本文基于天目一号气象星座 (TM-1) L2海面风速产品, 结合欧洲中期天气预报中心第五代全球再分析资料ERA5, 从风速区间、GNSS信号源及地理区域三个维度系统评估GNSS-R风速反演的全球适用性。统计结果表明: TM-1风速产品具备全球范围反演能力, 整体均方根误差 (RMSE) 为2. 22m/s, 且反演精度呈现显著的风速依赖性。10m/s以下的低风速区间反演精度较高, 但随风速增大反演精度逐渐下降, 尤其在高风速条件下对海洋表面粗糙度变化的感知能力存在一定局限性。此外, 不同GNSS信号源的风速反演精度存在差异, 其中Galileo信号最优, Glonass信号最差。在地理分布上, 风速反演精度随纬度增加呈下降趋势, 表现出明显的纬度梯度特征。这一现象表明, GNSS-R在低纬度地区具有良好的适用性, 但在高纬度极地地区受海冰覆盖、风浪增强等因素影响, 反演误差显著增加。本研究为GNSS-R风速反演的全球适用性提供了量化评估, 为未来GNSS-R在中高纬度及高风速条件下的优化应用奠定了基础。

Global Navigation Satellite System Reflectometry (GNSS-R) technology demonstrates significant potential in sea surface wind speed retrieval due to its advantages of low cost, strong signal penetration, and all-weather observation capabilities. However, current spaceborne GNSS-R research primarily focuses on low-latitude regions owing to the limited coverage of CYGNSS satellites, lacking systematic validation of GNSS-R wind speed retrieval' s global applicability. Therefore, this study systematically evaluates the global applicability of GNSS-R wind speed retrieval from three dimensions—wind speed range, GNSS signal sources, and geographical regions—using the Tianmu-1 meteorological constellation (TM-1) L2 sea surface wind speed product combined with ERA5, the fifth-generation global reanalysis data from the European Centre for Medium-Range Weather Forecasts. Statistical results indicate that TM-1 wind speed products exhibit global inversion capability with an overall root mean square error (RMSE) of 2. 22m/s, and the inversion accuracy shows a significant dependence on wind speed. The inversion accuracy is higher in the low wind speed range below 10m/s, but the inversion accuracy gradually decreases with increasing wind speed, particularly demonstrating limitations in sensing sea surface roughness variations under high wind speeds. Furthermore, wind speed retrieval accuracy varies among different GNSS signal sources, with Galileo signals showing optimal performance and Glonass signals the poorest. Geographically, inversion accuracy decreases with increasing latitude, displaying distinct latitudinal gradient characteristics. This phenomenon suggests GNSS-R maintains good applicability in low-latitude regions, while experiencing significantly increased inversion errors in high-latitude polar areas due to sea ice coverage and enhanced wind-wave interactions. This research provides quantitative assessment of GNSS-R' s global applicability for wind speed retrieval and establishes a foundation for optimizing GNSS-R applications in mid-high latitude regions and high wind speed conditions.