The Atmospheric Laser Doppler Instrument (ALADIN) onboard the Aeolus wind mission was the first High Spectral Resolution Lidar operating in the Ultra Violet (UV) region deployed in space. This study explores and documents the feasibility of deriving ocean optical properties using data from ALADIN. A three steps (i.e. data screening, analytical estimation of the total in-water signal contribution, Look Up Table-based estimation of the in-water attenuation) retrieval algorithm was developped combining data analysis and signal simulations from a radiative transfer model. The algorithm has been implemented using the signal acquired by the Mie channel, and tested for 1-year of Aeolus observations. This approach allowed estimating the first Aeolus derived Ocean Color (OC) products in terms of the total in-water signal contribution and the in-water attenuation term in a spectral region (355 nm) not covered, during Aeolous lifetime, by operational OC products. The validation process involved comparing these products with both Biogeochemical-Argo (BGC-Argo) field measurements and satellite OC dataset distributed by ESA Ocean Color Climate Change Initiative across a set of 7 selected oceanic regions representing diverse open-ocean scenarios. These validation exercises attested the general accordance between OC reference measurements and the proposed Aeolus OC parameters. Thus, this study was able to provide statistical evidence of the sensitivity of the retrieved Aeolus in-water lidar attenuation term to the CDOM variability on a temporal/seasonal and spatial/regional basis. A preliminary estimation of the uncertainty associated to the retrieved quality controlled , was performed assuming the radiometric noise as unique source of uncertainty. As a result, a median/average value of absolute relative percent difference of about 50/80% was obtained. Limits of the developed technique, possible improvements, potential adaptation to planned/future space lidar missions are discussed.

中文翻译：

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探索 Aeolus 激光雷达任务在海洋色彩应用中的潜力


风神风任务中搭载的大气激光多普勒仪器 (ALADIN) 是部署在太空中的第一个在紫外线 (UV) 区域运行的高光谱分辨率激光雷达。本研究探索并记录了使用 ALADIN 数据推导海洋光学特性的可行性。结合数据分析和辐射传输模型的信号模拟，开发了三步（即数据筛选、水中总信号贡献的分析估计、基于查找表的水中衰减估计）检索算法。该算法已使用 Mie 通道获取的信号实现，并针对 Aeolus 一年的观测进行了测试。这种方法可以根据总水内信号贡献和在 Aeolus 生命周期内未覆盖的光谱区域 (355 nm) 中的水中衰减项来估计第一批 Aeolus 衍生的海洋颜色 (OC) 产品。验证过程涉及将这些产品与生物地球化学-Argo (BGC-Argo) 现场测量和由 ESA 海洋颜色气候变化倡议在代表不同公海情景的 7 个选定海洋区域分发的卫星 OC 数据集进行比较。这些验证练习证明了 OC 参考测量值与建议的 Aeolus OC 参数之间的总体一致性。因此，本研究能够提供检索到的 Aeolus 水下激光雷达衰减项对时间/季节和空间/区域基础上 CDOM 变化的敏感性的统计证据。假设辐射噪声作为唯一的不确定性来源，对与检索的质量控制相关的不确定性进行了初步估计。 结果，获得约50/80％的绝对相对百分比差异的中值/平均值。讨论了所开发技术的局限性、可能的改进以及对计划/未来空间激光雷达任务的潜在适应。