HDO/H 2 O ratio retrievals from GOSAT
HDO/H 2 O ratio retrievals from GOSAT
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DOI：
10.5194/amt-6-599-2013
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发表时间：
2012-09
影响因子：
3.8
通讯作者：
H. Boesch;N. Deutscher;T. Warneke;K. Byckling;A. Cogan;D. Griffith;J. Notholt;R. Parker;Zhiting Wang
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文献类型：
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作者：
H. Boesch;N. Deutscher;T. Warneke;K. Byckling;A. Cogan;D. Griffith;J. Notholt;R. Parker;Zhiting Wang
抽象的。我们报告了一个新的短波红外（SWIR）检索的列平均HDO/H2O比从日本温室气体观测卫星（GOSAT）。通过综合模拟研究，我们估计，推断的δD值通常具有20‰（沙漠表面和30°太阳天顶角）和120‰（针叶树表面和60°太阳天顶角）之间的随机误差。我们发现，检索将有一个小的，但显着的灵敏度卷云的存在下，HDO的先验轮廓形状和大气温度，这有可能引入一些区域尺度的偏差在检索。通过与总碳柱观测网络（TCCON）的地基柱观测值进行比较，我们发现GOSAT和TCCON的δD之间的差异在北方半球站点约为−30‰，而在澳大利亚站点则增加到−70‰。澳大利亚网站的偏差显着降低时，减少空间共址的标准，这表明，空间平均有助于观察到的差异在澳大利亚。GOSAT反演允许映射全球分布的δD及其随季节的变化，我们发现在我们的全球GOSAT反演的预期强纬度梯度与显着增强的热带地区。与地面TCCON网络和全球反演结果的比较是非常令人鼓舞的，它们表明，从GOSAT反演的δD应该是一个有用的产品，可以用来补充热红外探测器和地面网络的数据集，并扩展最近结束的SCIAMACHY使命建立的SWIR反演的δD数据集。
Abstract. We report a new shortwave infrared (SWIR) retrieval of the column-averaged HDO/H2O ratio from the Japanese Greenhouse Gases Observing Satellite (GOSAT). From synthetic simulation studies, we have estimated that the inferred δD values will typically have random errors between 20‰ (desert surface and 30° solar zenith angle) and 120‰ (conifer surface and 60° solar zenith angle). We find that the retrieval will have a small but significant sensitivity to the presence of cirrus clouds, the HDO a priori profile shape and atmospheric temperature, which has the potential of introducing some regional-scale biases in the retrieval. From comparisons to ground-based column observations from the Total Carbon Column Observing Network (TCCON), we find differences between δD from GOSAT and TCCON of around −30‰ for northern hemispheric sites which increase up to −70‰ for Australian sites. The bias for the Australian sites significantly reduces when decreasing the spatial co-location criteria, which shows that spatial averaging contributes to the observed differences over Australia. The GOSAT retrievals allow mapping the global distribution of δD and its variations with season, and we find in our global GOSAT retrievals the expected strong latitudinal gradients with significant enhancements over the tropics. The comparisons to the ground-based TCCON network and the results of the global retrieval are very encouraging, and they show that δD retrieved from GOSAT should be a useful product that can be used to complement datasets from thermal-infrared sounder and ground-based networks and to extend the δD dataset from SWIR retrievals established from the recently ended SCIAMACHY mission.