High Summertime Aerosol Loadings Over the Arabian Sea and Their Transport Pathways
尘埃输送途径的MV-EOF分析
第4.2节中的结果表明，在整个研究领域，矿物尘埃气溶胶在陆地和海洋上的总气溶胶负荷中占主导地位。在本节中，研究了尘埃气溶胶的运输途径。在2000年至2016年的北方夏季，MODIS Terra AOD和ERAI风的MV-EOF分析证明了气溶胶与大气环流之间的关系（图 6）。图中的轮廓和箭头 6中分别以相关标准偏差为单位表示AOD和循环的协方差。阿拉伯海，阿拉伯半岛南部，和伊朗-阿富汗-巴基斯坦强阳性AOD方差加上强低级别（850百帕）西北在阿拉伯半岛（图第一MV-EOF部件 6，含义）西北方向可以将源头区域（阿拉伯半岛）的尘埃气溶胶输送到其下风区域（阿拉伯海和南印度）。印度北部的飓风有利于降水，这可能导致北印度的AOD变化。数字 6b（第二个MV-EOF分量）显示出与北阿拉伯海和南阿拉伯半岛上的西风相关的强正AOD变化。
MV‐EOF analysis of Moderate Resolution Imaging Spectroradiometer‐Terra Aerosol optical depth and ERAI wind (m/s). The left and right columns use winds at 850 and 500 hPa, respectively. The analysis uses June–July–August 2000–2016 monthly anomalies. Gray colors indicate missing values. The numbers in the upper‐right corner of each panel represent the variance explained by each mode of the MV‐EOF analysis. Note that the normalized EOF results has been scaled back to the actual units. MV‐EOF = Multivariate empirical orthogonal function.
Back trajectory analysis. Back trajectories of air masses at three locations over the Arabian Sea from northwest to southeast. The left and right columns represent back trajectories at the altitude of 500 and 5,000 m, respectively. Various colors of curves indicate various clusters of these back trajectories represented by thick lines with solid cycles overlaid. Each cycle represents the location of air mass that is 12 hr ahead or behind its neighbors, so totally it tracks back to 84 hr. The percent numbers represent the percent of back trajectories in each cluster in the total back trajectories.
