FY-3E plays a vital role in the meteorological global earth observing system. Precipitable water vapor (PWV) is an essential parameter for the water cycle and global climate change. Here, we carry out the PWV retrieval using the MERSI-LL sensor onboard the FY-3E satellite for the first time. The retrieval accuracy under different cloudage conditions is validated by the extra PWV from ground-based GNSS and spaceborne occultation. For the results against ground-based GNSS, the total accuracy shows an RMSE of 2.69–3.36 mm as the clouds increase, and correlation coefficients higher than 0.95. The spatial accuracy distribution indicates that inland stations have higher accuracy than the coast and island stations. As for the results against spaceborne occultation, the verification accuracy varies with the spatial pairing distance, showing poor accuracy in the low latitude area. This study can provide an essential reference for the community to understand the current water vapor inversion performance of MERSI-LL.

中文翻译：

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使用 FY-3E 机载 MERSI-LL 进行首次 PWV 反演，并使用共平台掩星和地面 GNSS 进行交叉验证

FY-3E在气象全球对地观测系统中发挥着至关重要的作用。可降水蒸气（PWV）是水循环和全球气候变化的重要参数。在这里，我们首次利用FY-3E卫星上的MERSI-LL传感器进行PWV反演。通过地基GNSS​​和星载掩星的额外PWV验证了不同云量条件下的反演精度。对于地面 GNSS 的结果，随着云层的增加，总精度显示 RMSE 为 2.69-3.36 mm，相关系数高于 0.95。空间精度分布表明内陆站的精度高于沿海和岛屿站。对于星载掩星结果，验证精度随空间配对距离的不同而变化，在低纬度地区精度较差。本研究可为业界了解MERSI-LL当前水汽反演性能提供重要参考。