Evaluation of AIRS Cloud-Thermodynamic-Phase Determination with CALIPSO
Evaluation of AIRS Cloud-Thermodynamic-Phase Determination with CALIPSO
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DOI：
10.1175/jamc-d-13-0137.1
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发表时间：
2014-04
影响因子：
3
通讯作者：
H. Jin;S. Nasiri
中科院分区：
文献类型：
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作者：
H. Jin;S. Nasiri
利用云-气溶胶激光雷达和红外探路者卫星观测(CALIPSO)的云热力学相对基于红外的大气红外测深仪(AIRS)的云热力学位相进行了评估。AIRS云相是由8-12 mm窗口内的光谱信息得到的，CALIPSO利用532 nm通道的去偏振能力提供了一致的像素尺度的云相观测。对单层(占所有云的48.5%)、异质层(45.9%)和多层(5.6%)云的AIRS和CALIPSO云相观测进行了比较。在全球90%以上的一致观测中，AIRS冰相与CALIPSO是一致的，在高纬度和多层云中发现的差异最大。AIRS的水相总体上遵循CALIPSO的空间型，但频率要低约2倍。冰和waterphasesofAIRSbothshowmisclassificationsabout1%ofthetimewhencomparedwithCALIPSO.Not所有的云在AIRS谱上表现出很强的位相特征，这导致AIRS将未知位相分类为CALIPSO约10%的冰云和60%的CALIPSO水云。这项研究表明，thealgorithmiscapableofdetectingicecloudswithintheAIRSfieldofviewandcanbeusedasthefirststepin进一步反演了冰云光学厚度和有效粒子尺寸。
Atmospheric Infrared Sounder (AIRS) infrared-based cloud-thermodynamic-phase retrievals are evaluated using the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) cloud thermodynamic phase. The AIRS cloud phase is derived from spectral information contained within the 8‐12-mm window, and CALIPSO provides coincident pixel-scale observations of cloud phase using the depolarization capabilityof the532-nmchannel.Comparisons are performed betweentheAIRS andCALIPSOcloud-phase observations for single-layer (48.5% of all clouds), heterogeneous-layer (45.9%), and multilayered (5.6%) clouds. The AIRS ice phase is in agreement with CALIPSO for more than 90% of coincident observations globally, with the largest discrepancies found in high latitudes and multilayered clouds. AIRS water phase generally follows CALIPSO spatial patterns, but the frequency is lower by about a factor of 2. The ice and waterphasesofAIRSbothshowmisclassificationsabout1%ofthetimewhencomparedwithCALIPSO.Not all clouds demonstrate strong phase signatures in the AIRS spectrum, which leads AIRS to classify unknown phase to around 10% of CALIPSO’s ice clouds and 60% of CALIPSO’s water clouds. This study shows that thealgorithmiscapableofdetectingicecloudswithintheAIRSfieldofviewandcanbeusedasthefirststepin further retrievals of ice-cloud optical thickness and effective particle size.