TEsting isotopologues as Diabatic heating proxy for atmospheric Data analYses

云和水蒸气控制着大气的辐射加热/冷却，而水的凝结或蒸发则决定了潜热加热或潜热消耗发生的位置。然后，加热模式驱动大气环流，从而导致额外的蒸发/冷凝，并影响水蒸气和云的分布，这反过来又改变了大气的潜在和辐射加热模式。水分路径、非绝热加热和大气环流之间的这种强耦合是重要的气候反馈机制和许多恶劣天气事件演变的原因。在这种情况下，它是相当令人担忧的，从不同的当前全球再分析得到的非绝热加热率显示出显着的不一致性。本项目的目的是开发和评估一种新的方法，使大气再分析更好地符合实际的大气加热率。该方法包括在探索过程中的信息存在于大气中的水蒸气同位素组成内的一种新的数据同化框架。由于同位素组成与大气非绝热潮湿过程密切相关，其额外的同化提供了一个有希望的可能性，更好地约束分析的大气状态对实际的大气加热速率。专家之间的密切合作将有效地实现这一目标。德国的水蒸气同位素天基遥感专家将利用红外大气探测干涉仪传感器测得的光谱，生成一组具有全面特征的观测数据，这些数据代表晴空和均匀低云条件，并在2014-2016年三年内每天两次提供准全球覆盖。日本全球同位素体建模和数据同化专家将改进其局部包络变换卡尔曼滤波同化工具，以确保每天两次对全球同位素体观测进行计算效率高和准确的同化。德国和日本科学家将在2014-2016年期间共同进行不同的同化实验，并记录该方法的挑战及其改善大气分析的潜力。这次评估的一个特别重点将是马登-朱利安振荡的加热率和降水模式以及哈德利和步行者环流的加热率、水平风和垂直速度。观测数据和开发的工具将免费提供，从而使同位素同化工具能够与任何同位素启用的大气环流模型一起持续使用。

Clouds and water vapour control atmospheric radiative heating/cooling and condensation or evaporation of water determines where latent heating or latent heat consumption takes place. The heating patterns then drive atmospheric circulation, thereby causing additional evaporation/condensation and impacting on the distribution of water vapour and clouds, which in turn again modify the latent and radiative heating patterns of the atmosphere. This strong coupling between moisture pathways, diabatic heating and atmospheric circulation is responsible for important climate feedback mechanisms and for the evolution of many severe weather events. In this context it is rather worrisome that the diabatic heating rates obtained from different current global reanalyses show significant inconsistencies.The aim of this project is to develop and evaluate a novel method for bringing atmospheric reanalyses in better accordance to the actual atmospheric heating rates. The method consists in exploring the process information present in the atmospheric water vapour isotopologue composition within a novel data assimilation framework. Because the isotopologue composition is closely linked to atmospheric diabatic moist processes, its additional assimilation offers a promising possibility for better constraining the analysed atmospheric state towards the actual atmospheric heating rates. The aim will be efficiently achieved by a close collaboration between experts. German experts in space-based remote sensing of water vapour isotopologues will use spectra measured by the sensor IASI (Infrared Atmospheric Sounding Interferometer) and generate a comprehensively characterized observational data set representative for clear sky and homogeneously low cloud conditions and offering quasi global coverage two times per day for the three years 2014-2016. Japanese experts in global isotopologue modelling and data assimilation will refine their Local Ensemble Transform Kalman Filter (LETKF) assimilation tool in order to ensure a computationally efficient and accurate assimilation of global isotopologue observations twice per day. The German and Japanese scientists will together run different assimilation experiments for the 2014-2016 time period and document the challenges of the approach and its potential for improving atmospheric analyses. A particular focus of this evaluation will be on the heating rates and precipitation patterns of the Madden-Julian oscillation and the heating rates, horizontal winds and vertical velocities of the Hadley and Walker circulations. The observational data and the developed tools will be made freely available, thereby permitting continual usage of the isotopologue assimilation tool with any isotopologue enabled atmospheric general circulation model.