Process-evaluation of tropospheric humidity simulated by general circulation models using water vapor isotopologues: 1. Comparison between models and observations
Process-evaluation of tropospheric humidity simulated by general circulation models using water vapor isotopologues: 1. Comparison between models and observations
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DOI：
10.1029/2011jd016621
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发表时间：
2012-03
影响因子：
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通讯作者：
C. Risi;D. Noone;J. Worden;C. Frankenberg;G. Stiller;Michael T. Kiefer;B. Funke;K. Walker;P. Bernath;M. Schneider;D. Wunch;V. Sherlock;N. Deutscher;D. Griffith;P. Wennberg;K. Strong;D. Smale;E. Mahieu;S. Barthlott;F. Hase;O. García;J. Notholt;T. Warneke;G. Toon;D. Sayres;S. Bony;Jeonghoon Lee;D. Brown;R. Uemura;C. Sturm
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作者：
C. Risi;D. Noone;J. Worden;C. Frankenberg;G. Stiller;Michael T. Kiefer;B. Funke;K. Walker;P. Bernath;M. Schneider;D. Wunch;V. Sherlock;N. Deutscher;D. Griffith;P. Wennberg;K. Strong;D. Smale;E. Mahieu;S. Barthlott;F. Hase;O. García;J. Notholt;T. Warneke;G. Toon;D. Sayres;S. Bony;Jeonghoon Lee;D. Brown;R. Uemura;C. Sturm
本研究的目的是确定如何使用水蒸气中的 H2O 和 HDO 测量来检测和诊断大气环流模型 (GCM) 中控制对流层湿度的过程表示中的偏差。我们分析了大量对整个自由对流层不同高度敏感的同位素数据集（四颗卫星、十六颗地面遥感数据、五个表面原位数据集和三个飞机数据集）。尽管数据集之间存在显着差异，但我们确定了一些观察到的 HDO/H2O 特征，这些特征在数据集中具有稳健性，并且可用于评估模型。我们评估同位素 GCM LMDZ，考虑时空采样和仪器灵敏度的影响。我们发现 LMDZ 很好地再现了对流层中低层和中层的空间模式。然而，它低估了亚热带和中纬度地区各级同位素组成季节性变化的幅度，并且这种偏差在所有数据集中都是一致的。与卫星数据集相比，LMDZ 还低估了观测到的经向同位素梯度以及干燥和对流热带地区之间的对比。与 SWING2 项目中其他六种同位素启用的 GCM 进行比较表明，LMDZ 所表现出的偏差对于所有模型都是常见的。 SWING2 GCM 显示同位素行为的分布非常大，与湿度的行为没有明显相关，这表明水蒸气同位素测量可用于暴露模型的缺陷。在一篇配套论文中，模型之间的同位素差异是根据控制湿度过程的表示偏差来解释的。版权所有 © 2012 美国地球物理联盟。
The goal of this study is to determine how H2O and HDO measurements in water vapor can be used to detect and diagnose biases in the representation of processes controlling tropospheric humidity in atmospheric general circulation models (GCMs). We analyze a large number of isotopic data sets (four satellite, sixteen ground-based remote-sensing, five surface in situ and three aircraft data sets) that are sensitive to different altitudes throughout the free troposphere. Despite significant differences between data sets, we identify some observed HDO/H2O characteristics that are robust across data sets and that can be used to evaluate models. We evaluate the isotopic GCM LMDZ, accounting for the effects of spatiotemporal sampling and instrument sensitivity. We find that LMDZ reproduces the spatial patterns in the lower and mid troposphere remarkably well. However, it underestimates the amplitude of seasonal variations in isotopic composition at all levels in the subtropics and in midlatitudes, and this bias is consistent across all data sets. LMDZ also underestimates the observed meridional isotopic gradient and the contrast between dry and convective tropical regions compared to satellite data sets. Comparison with six other isotope-enabled GCMs from the SWING2 project shows that biases exhibited by LMDZ are common to all models. The SWING2 GCMs show a very large spread in isotopic behavior that is not obviously related to that of humidity, suggesting water vapor isotopic measurements could be used to expose model shortcomings. In a companion paper, the isotopic differences between models are interpreted in terms of biases in the representation of processes controlling humidity. Copyright © 2012 by the American Geophysical Union.