Sea Ice Motion Vector Retrievals from AMSR2 89-GHz Data: Validation Algorithm with Simultaneous Multichannel Observations
Sea Ice Motion Vector Retrievals from AMSR2 89-GHz Data: Validation Algorithm with Simultaneous Multichannel Observations
复制标题
从 AMSR2 89 GHz 数据检索海冰运动矢量：具有同时多通道观测的验证算法
DOI：
10.1175/jtech-d-22-0049.1
复制
发表时间：
2023
影响因子：
2.2
通讯作者：
and K. Shimada
中科院分区：
文献类型：
--
作者：
Yoshizawa E.;T.;Kamoshida;and K. Shimada
在反演海冰运动矢量（SIMVs）的基础上被动微波观测，使用的高分辨率89 GHz通道的先进微波扫描辐射计2（AMSR 2）的优势，提高理论精度的相关运动跟踪。然而，它对大气湿度的敏感性比低频通道更高，将最大互相关峰值与离群向量联系起来，并掩盖了有效向量的信号。本研究开发了一种算法，以选择有效的矢量从候选人检测的多个互相关峰值的基础上验证与大规模海冰位移提取19-和37-GHz的数据后，可疑的矢量进行预过滤，通过比较它们与再分析表面风和邻近的矢量。该算法选择一个对应于大规模运动的矢量作为最优矢量。2013 - 2020年的反演结果表明，通过用第二或第三个互相关峰检测到的有效向量替换离群向量，同时观测的验证可以在冬季从89 GHz数据中反演超过60%的北极运动场，但在夏季只有10%，因此，使用较低频率的数据进行反演。使用海洋系泊装置声学测量的现场数据进行的不确定性评估表明，在理想的冬季条件下，该算法提供的每日SIMV的均方根误差仅为1-2 cm s-1，并且不存在昼夜亮温（Tb）变化，这使得跟踪Tb场的相似性变得困难。分析还说明了该算法的适用范围限制夏季restoration.Significance StatementAn算法开发，以验证海冰运动矢量从AMSR 2 89-GHz的数据从低频数据检索。通过同时观测的验证，使有效的矢量从无效的天气影响。
In retrievals of sea ice motion vectors (SIMVs) based on passive microwave observations, the use of the high-resolution 89-GHz channel of the Advanced Microwave Scanning Radiometer 2 (AMSR2) has the advantage of enhancing the theoretical precision of correlation-based motion tracking. However, its higher sensitivity to atmospheric moisture than lower-frequency channels links maximum cross-correlation peaks to outlier vectors and obscures signals of valid vectors. This study develops an algorithm to select valid vectors from candidates detected by multiple cross-correlation peaks based on validations with large-scale sea ice displacements extracted from 19- and 37-GHz data after questionable vectors are prefiltered by comparing them with reanalysis surface wind and neighboring vectors. The algorithm selects a vector corresponding to large-scale motion as the optimal vector. The retrieved results from 2013 to 2020 show that by replacing outlier vectors with valid ones detected by second or third cross-correlation peaks, validation with simultaneous observations enables retrieval of more than 60% of the Arctic motion field from 89-GHz data in winter but only 10% in summer; therefore, lower-frequency data are employed for retrievals. The uncertainty assessment using in situ data from acoustic measurements from ocean moorings shows that the algorithm provides daily SIMVs with root-mean-square errors of only 1–2 cm s–1in idealized winter conditions with the absence of diurnal brightness temperature (Tb) changes that make tracking of the similarity of Tb fields difficult. The analysis also illustrates the applicability limit of the algorithm for summer retrievals.Significance StatementAn algorithm was developed to validate sea ice motion vectors retrieved from AMSR2 89-GHz data by those from lower-frequency data. The validation via simultaneous observations enabled that valid vectors are sorted from invalid ones resulting from weather effects.