Improved Sea Ice Fraction Characterization for L-Band Observations by the Aquarius Radiometers
Improved Sea Ice Fraction Characterization for L-Band Observations by the Aquarius Radiometers
复制标题
改进了 Aquarius 辐射计 L 波段观测的海冰分数表征
DOI：
--
复制
发表时间：
2017
影响因子：
8.2
通讯作者：
L. Brucker
中科院分区：
文献类型：
--
作者：
E. Dinnat;L. Brucker
工作在L波段(1.4GHz)的辐射计被用来在无冰海洋上反演海面盐度，最近也被用来研究冰冻层。在高纬度地区使用它们的一个障碍是混合场景的优势，在这种场景中，海水和海冰都出现在传感器的视野(FOV)中。准确地描述场景对于海洋学和冰冻圈应用是至关重要的。为此，使用了海冰比例模型，该模型由被动微波海冰浓度反演和一个仪器模拟器组成，该模拟器综合了天线周围的辐射功率。我们研究了目前用于推导影响宝瓶座观测的冰分数的模型，并表明它可以显著改进。一方面，目前的模型倾向于高估边缘冰区的海冰比例，因为在边缘冰区，观测数据被用于盐度反演。另一方面，目前的模型低估了冰包中的冰比例，在冰包中，观测是用来推导海冰特性的。对于北半球，我们还发现了海冰类型对L波段辐射观测影响的证据。我们提出了一个模型，利用先进的微波扫描辐射计2 Bootstrap算法计算海冰浓度，并在传感器的视场上使用高分辨率积分，从而得到与宝瓶座辐射观测更一致的海冰分数。
Radiometers operating at L-band (1.4 GHz) are used to retrieve sea surface salinity over ice-free oceans and have been used recently to study the cryosphere. One hindrance of their use in the high latitudes is the preponderance of mixed scenes, where seawater and sea ice are both present in the sensor’s field of view (FOV). Accurately characterizing the scene is crucial for oceanographic and cryospheric applications. To that end, a sea ice fraction model, composed of passive microwave sea ice concentration retrievals and an instrument simulator that integrates radiative power coming from all around the antenna, is used. We investigate the model currently used operationally to derive the ice fraction affecting the Aquarius observations and show that it can be significantly improved. On the one hand, the current model tends to overestimate sea ice fraction in the marginal ice zone where observations are used for salinity retrievals. On the other hand, the current model underestimates ice fraction within the ice pack where observations are used to derive sea ice properties. For the northern hemisphere, we also find evidence of the sea ice type impact on L-band radiometric observations. We present a model to derive sea ice fractions that are in better agreement with Aquarius radiometric observations using the Advanced Microwave Scanning Radiometer 2 Bootstrap algorithm for sea ice concentration and using high-resolution integration over the sensor’s FOV.