A Tropospheric Emission Spectrometer HDO/H 2 O retrieval simulator for climate models
A Tropospheric Emission Spectrometer HDO/H 2 O retrieval simulator for climate models
复制标题
用于气候模型的对流层发射光谱仪 HDO/H 2 O 反演模拟器
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
R. Healy
中科院分区：
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作者：
R. Field;C. Risi;G. Schmidt;J. Worden;A. Voulgarakis;A. Legrande;A. Sobel;R. Healy
大气对流层发射光谱仪（TES）的水汽同位素组成的反演在约束气候模式中的潮湿过程中具有独特的价值。模拟值和检索值之间的准确比较要求排除检索较差的模型剖面，并将仪器操作器应用于剩余剖面。通常情况下，这是通过在卫星测量点采样模型输出，并使用质量标志和平均内核从个别检索在特定的地点和时间。当影响反演灵敏度的模式气象条件与仪器在短时间尺度上观测到的气象条件不同时，这种方法是不可靠的，自由运行的气候模拟就是这种情况。在这项研究中，我们描述了一种替代的，“分类”的方法来应用仪器操作员，在美国宇航局GISS ModelE大气环流模型。反演质量和平均核结构是根据模式条件经验预测的，而不是从卫星观测中获得的。该方法可用于任意模式配置，且不要求卫星反演气象与模式气象在短时间尺度上的一致性。为了测试这种方法，使用基于检索的操作符和分类操作符进行了轻推模拟。云量、地面温度和自由对流层含水量是反演质量和平均核结构的最重要预测因子。在应用基于反演的和更详细的分类算子后，D场之间有很好的一致性，相对于原始模型场，海洋上的D场增加了30 ‰，陆地上的D场减少了40 ‰。猫- egorical算子在海洋上比在陆地上表现得更好，并且需要进一步改进以用于热带以外。应用TES算子后，与TES D相比，ModelE在海洋上的D偏差为8 ‰，在陆地上的D偏差为34 ‰，这小于使用原始模型D场的偏差。
Retrievals of the isotopic composition of water vapor from the Aura Tropospheric Emission Spectrometer (TES) have unique value in constraining moist processes in climate models. Accurate comparison between simulated and retrieved values requires that model profiles that would be poorly retrieved are excluded, and that an instrument op- erator be applied to the remaining profiles. Typically, this is done by sampling model output at satellite measurement points and using the quality flags and averaging kernels from individual retrievals at specific places and times. This ap- proach is not reliable when the model meteorological con- ditions influencing retrieval sensitivity are different from those observed by the instrument at short time scales, which will be the case for free-running climate simulations. In this study, we describe an alternative, "categorical" approach to applying the instrument operator, implemented within the NASA GISS ModelE general circulation model. Retrieval quality and averaging kernel structure are predicted empiri- cally from model conditions, rather than obtained from collo- cated satellite observations. This approach can be used for ar- bitrary model configurations, and requires no agreement be- tween satellite-retrieved and model meteorology at short time scales. To test this approach, nudged simulations were con- ducted using both the retrieval-based and categorical opera- tors. Cloud cover, surface temperature and free-tropospheric moisture content were the most important predictors of re- trieval quality and averaging kernel structure. There was good agreement between the D fields after applying the retrieval-based and more detailed categorical operators, with increases of up to 30 ‰ over the ocean and decreases of up to 40 ‰ over land relative to the raw model fields. The cat- egorical operator performed better over the ocean than over land, and requires further refinement for use outside of the tropics. After applying the TES operator, ModelE had D bi- ases of 8 ‰ over ocean and 34 ‰ over land compared to TES D, which were less than the biases using raw model D fields.