Accurate Liquid Water Path Retrieval from Low-Cost Microwave Radiometers Using Additional Information from a Lidar Ceilometer and Operational Forecast Models
Accurate Liquid Water Path Retrieval from Low-Cost Microwave Radiometers Using Additional Information from a Lidar Ceilometer and Operational Forecast Models
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DOI：
10.1175/jtech2053.1
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发表时间：
2007-09
影响因子：
2.2
通讯作者：
N. Gaussiat;R. Hogan;A. Illingworth
中科院分区：
文献类型：
--
作者：
N. Gaussiat;R. Hogan;A. Illingworth
摘要水云对地球辐射平衡有重要影响。使用地基双频微波辐射计推导液态水路径（LWP）和水汽路径（WVP）是公认的，但不确定性的干，水汽和液态水的吸收系数和辐射校准可能会导致错误的检索LWP。本文介绍了一种利用激光雷达云高计的附加信息来识别液态水云及其高度的方法。当这种云不存在时，两个频率的辐射校准被最佳地调整，使得检索到的LWP被强制为零;当它们存在时，校准是从之前和之后最近的晴朗天空时段内插的，并且云的温度被用于改进液态水吸收系数（从预报模型中获取的温度廓线）。这个过程是不敏感的吸收模型的选择，…
Abstract Water clouds have an important impact on the radiative balance of the earth. The use of ground-based dual-frequency microwave radiometers to derive both liquid water path (LWP) and water vapor path (WVP) is well established, but uncertainties over the dry, water vapor, and liquid water absorption coefficients and the radiometric calibration can lead to errors in the retrieved LWP. A method in which additional information from a lidar ceilometer is used to identify the presence of liquid water clouds and their altitude is described. When such clouds are absent, the radiometric calibrations of the two frequencies are optimally adjusted so that the retrieved LWP is forced to zero; when they are present the calibrations are interpolated from the nearest clear-sky periods before and after, and the temperature of the cloud is used to refine the liquid water absorption coefficient (with the temperature profile taken from a forecast model). This procedure is insensitive to the choice of absorption model,...