Implementation of cloud retrievals for TES atmospheric retrievals: 2. Characterization of cloud top pressure and effective optical depth retrievals
Implementation of cloud retrievals for TES atmospheric retrievals: 2. Characterization of cloud top pressure and effective optical depth retrievals
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TES大气反演云反演的实现：2.云顶压力特征和有效光学深度反演
DOI：
10.1029/2007jd008858
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发表时间：
2008
影响因子：
--
通讯作者：
G. Osterman
中科院分区：
文献类型：
--
作者：
A. Eldering;S. Kulawik;J. Worden;K. Bowman;G. Osterman
我们将对流层发射光谱仪（TES）估算的有效云光学深度和云顶高度与EOS上的中分辨率成像光谱仪（MODIS）、大气红外探测器（AIRS）和模拟数据进行了比较，并对TES的云产品进行了表征和验证。TES测量红外光谱区域（650-2260 cm−1），在该区域，云对测量的辐射有普遍的影响，因此对痕量气体剖面的检索也有影响。在TES检索中，云的辐射贡献是根据一组频率相关的非散射有效光学深度和云高度参数化的。这种独特的方法联合检索云参数与地表温度，发射率，大气温度和微量气体，如臭氧从TES光谱辐射。我们计算了在单散射反照率和相位函数范围内TES有效光学深度与真实光学深度之间的关系，以显示其随云类型的变化情况。我们使用涵盖广泛云案例的模拟数据集估计检索云参数的误差。对于辐射无噪声的模拟，云高误差小于30 hPa，有效光学深度符合输入光学深度小于3的预期行为。在考虑辐射随机噪声和大气变量的情况下，云高误差约为200 hPa，估算有效光学深度的灵敏度在0.3 ~ 10之间。模拟的估计误差与TES与MODIS和AIRS的云顶高度和光学深度的差异是一致的。
[1] We characterize and validate the cloud products from the Tropospheric Emission Spectrometer (TES) by comparing TES estimates of effective cloud optical depth and cloud top height to those from the Moderate Resolution Imaging Spectroradiometer (on EOS) (MODIS), the Atmospheric Infrared Sounder (AIRS), and to simulated data. TES measures in the infrared spectral region (650–2260 cm−1), where clouds have a ubiquitous impact on measured radiances and therefore on trace gas profile retrievals. The radiance contribution of clouds is parameterized in TES retrievals in terms of a set of frequency-dependent nonscattering effective optical depths and a cloud height. This unique approach jointly retrieves cloud parameters with surface temperature, emissivity, atmospheric temperature, and trace gases such as ozone from TES spectral radiances. We calculate the relationship between the true optical depth and the TES effective optical depth for a range of single-scatter albedo and phase functions to show how this varies with cloud type. We estimate the errors on retrieved cloud parameters using a simulated data set covering a wide range of cloud cases. For simulations with no noise on the radiances, cloud height errors are less than 30 hPa, and effective optical depth follows expected behavior for input optical depths of less than 3. When random noise is included on the radiances, and atmospheric variables are included in the retrieval, cloud height errors are approximately 200 hPa, and the estimated effective optical depth has sensitivity between optical depths of 0.3 and 10. The estimated errors from simulation are consistent with differences between TES and cloud top heights and optical depth from MODIS and AIRS.