Airborne validation of radiative transfer modelling of ice clouds at millimetre and sub-millimetre wavelengths
Airborne validation of radiative transfer modelling of ice clouds at millimetre and sub-millimetre wavelengths
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DOI：
10.5194/amt-2018-308
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发表时间：
2018-09
期刊：
影响因子：
2.9
通讯作者：
S. Fox;J. Mendrok;P. Eriksson;Robin Ekelund;S. O'Shea;K. Bower;R. Harlow;J. Pickering
中科院分区：
文献类型：
--
作者：
S. Fox;J. Mendrok;P. Eriksson;Robin Ekelund;S. O'Shea;K. Bower;R. Harlow;J. Pickering
抽象的。下一代欧洲极地轨道气象卫星将携带一种新型仪器——冰云成像仪（ICI），它使用 183 至 664 GHz 之间的被动观测来对云冰进行日常全球观测。成功利用这些观测结果需要对云冰散射进行精确建模，本研究使用机载大气测量设施 (FAAM) BAe-146 研究飞机的两次飞行的机载观测结果，利用大气辐射传输模拟器 (ARTS) 和最先进的云冰光学特性数据库，验证 325 至 664 GHz 频率下卷云的辐射传输模拟。特别注意通过结合同一云的遥感和现场观测来确保辐射传输模型的输入代表真实的大气状态，以创建与观测到的颗粒尺寸分布和大块冰质量一致的云特性的真实垂直剖面。将模拟结果与国际亚毫米机载辐射计 (ISMAR) 的测量结果进行比较，ISMAR 是 ICI 的机载演示器。结果表明，虽然它们通常能够重现观测到的云信号，但对于给定的冰水路径（IWP），对云微物理（包括云内冰质量的分布和冰颗粒习性）具有相当大的敏感性。因此，ICI 的准确检索需要云微物理特性的真实表示。
Abstract. The next generation of European polar orbiting weather satellites will carry a novel instrument, the Ice Cloud Imager (ICI), which uses passive observations between 183 and 664 GHz to make daily global observations of cloud ice. Successful use of these observations requires accurate modelling of cloud ice scattering, and this study uses airborne observations from two flights of the Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft to validate radiative transfer simulations of cirrus clouds at frequencies between 325 and 664 GHz using the Atmospheric Radiative Transfer Simulator (ARTS) and a state-of-the-art database of cloud ice optical properties. Particular care is taken to ensure that the inputs to the radiative transfer model are representative of the true atmospheric state by combining both remote-sensing and in-situ observations of the same clouds to create realistic vertical profiles of cloud properties that are consistent with both observed particle size distributions and bulk ice mass. The simulations are compared to measurements from the International Submillimetre Airborne Radiometer (ISMAR), which is an airborne demonstrator for ICI. It is shown that whilst they are generally able to reproduce the observed cloud signals, for a given ice water path (IWP) there is considerable sensitivity to the cloud microphysics including the distribution of ice mass within the cloud and the ice particle habit. Accurate retrievals from ICI will therefore require realistic representations of cloud microphysical properties.