Correlation Structures between Satellite All-Sky Infrared Brightness Temperatures and the Atmospheric State at Storm Scales
Correlation Structures between Satellite All-Sky Infrared Brightness Temperatures and the Atmospheric State at Storm Scales
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DOI：
10.1007/s00376-021-0352-3
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发表时间：
2021-04
影响因子：
5.8
通讯作者：
Yunji Zhang;E. Clothiaux;D. Stensrud
中科院分区：
文献类型：
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作者：
Yunji Zhang;E. Clothiaux;D. Stensrud
本研究探讨了GOES-16卫星上先进基线成像仪（ABI）三个水汽通道的红外（IR）亮度温度（bt）与大气状态之间的相关结构。基于集成的数据同化技术，如集成卡尔曼滤波（EnKF），依靠相关性将bt的创新传播到模型状态变量的增量。由于这3个水汽通道对对流层不同层的水汽都很敏感，因此它们与晴空区水汽相关性最强的高度与其各自加权函数的峰值密切相关。在多云地区，最强的相关性出现在深云的云顶，冰水成物与BT的相关性通常比液态水成物更强。随着垂直和水平距离的增加，相关性的大小从峰值开始下降。相关性如何降低取决于云的场景和云的结构，以及模型变量。在完全多云地区，bt与水汽以及水成物之间的水平相关性在约30公里处降至几乎为零。晴空地区与大气状态变量的水平相关性更广，在~ 100公里范围内保持非零值。本研究结果为水平和垂直定位方案中截断半径的合理选择提供了参考。它们还提供了最有效和最有效地利用不同水蒸气通道的见解。
This study explores the structures of the correlations between infrared (IR) brightness temperatures (BTs) from the three water vapor channels of the Advanced Baseline Imager (ABI) onboard the GOES-16 satellite and the atmospheric state. Ensemble-based data assimilation techniques such as the ensemble Kalman filter (EnKF) rely on correlations to propagate innovations of BTs to increments of model state variables. Because the three water vapor channels are sensitive to moisture in different layers of the troposphere, the heights of the strongest correlations between these channels and moisture in clear-sky regions are closely related to the peaks of their respective weighting functions. In cloudy regions, the strongest correlations appear at the cloud tops of deep clouds, and ice hydrometeors generally have stronger correlations with BT than liquid hydrometeors. The magnitudes of the correlations decrease from the peak value in a column with both vertical and horizontal distance. Just how the correlations decrease depend on both the cloud scenes and the cloud structures, as well as the model variables. Horizontal correlations between BTs and moisture, as well as hydrometeors, in fully cloudy regions decrease to almost 0 at about 30 km. The horizontal correlations with atmospheric state variables in clear-sky regions are broader, maintaining non-zero values out to ∼100 km. The results in this study provide information on the proper choice of cut-off radii in horizontal and vertical localization schemes for the assimilation of BTs. They also provide insights on the most efficient and effective use of the different water vapor channels.