Upper tropospheric humidity and climate change

在我们头顶许多公里以上的空气中，少量的水蒸气对地球的温室效应和持续的气候变化至关重要。它通过吸收向外发射的红外辐射来调节地球的自然冷却系统，湿度超过饱和点的地方决定了高空云的分布和厚度。对流层上层湿度是一个重要的气候变量，因为它控制着关键的大气过程，包括水蒸气和云反馈，这些过程可以放大气候系统对二氧化碳等其他温室气体增加的反应。因此，了解对流层上层湿度的过去变率和变化，并在复杂的气候预测模式中评估这些关键过程是至关重要的。该项目将利用最先进的全球卫星测量和新的诊断工具来评估数据集的质量，量化大气湿度在空间和时间上的变化，并利用这些信息来推进对重要大气过程的理解，以及询问和改进对社会有很大好处的详细天气和气候预测模型。这项研究将在地球观测和气候模拟之间提供一个有价值的接口，并阐明对气候变化至关重要的反馈过程，因此与决策者有很大的相关性。监督小组将提供气候科学和地球观测方面的广泛专业知识，并将有机会与英国气象局参与天气和气候模型开发的科学家以及驻扎在欧洲气象卫星组织（EUMETSAT）的直接参与生产和扩展关键卫星观测系统的科学家合作。该项目将解决一些重要的问题，包括：对流层上层的湿度在多大程度上放大了气候变化？-目前最先进的气候模式能否捕捉到决定对流层上层湿度变率和变化的过程？-对流层上层湿度的特征是否会为高空云反馈提供新的见解？-对流层上层的湿度如何控制地球的辐射能量平衡，是否存在热带超级温室效应？该项目将利用现有的数据、数值模型和诊断工具，并推动这些系统更好地将地球观测和气候建模结合起来，并开发与反馈过程有关的概念，这些概念对政策相关的定量气候科学至关重要，如下所列：-利用新的卫星测量UTH。-利用合作伙伴提供的现有软件开发技术，在当前气候模式中模拟一致的对流层上层湿度诊断-如何将对流层上层湿度测量与地球辐射预算和水循环测量相结合。将有机会与参与开发对流层上层湿度数据集的EUMETSAT合作伙伴联系并学习。欧空局水汽气候变化倡议和英国气象局合作使用和评估气候模型模拟。这将提供应用于模型和地球观测的跨学科数据分析技能的全面培训。

The tiny quantities of water vapour in the air many kilometres above our heads is of central importance to theEarth's greenhouse effect and ongoing climate change. It regulates the planet's natural cooling system throughabsorption of outgoing infrared radiation and where the humidity exceeds saturation point determines thedistribution and thickness of high altitude clouds. Upper tropospheric humidity is an essential climate variablebecause it controls key atmospheric processes, including water vapour and cloud feedbacks that can amplify theclimate system's response to increases in other greenhouse gases such as carbon dioxide. It is therefore vital tounderstand past variability and change in upper tropospheric humidity and evaluate these key processes incomplex climate prediction models.This project will exploit state of the art global satellite measurements and novel diagnostic tools to evaluatedataset quality, quantify the variability of atmospheric humidity in space and time and use this information toadvance understanding of important atmospheric processes as well interrogate and improve detailed weather andclimate prediction models that are of great benefit to society. The research will provide a valuable interfacebetween Earth Observation and climate modelling, as well elucidating feedbacks processes fundamental toclimate change and therefore of great relevance to policymakers. The supervision team provides a broadexpertise across climate science and Earth Observation and there will be the opportunity to work with scientistsfrom the UK Met Office involved in the development of weather and climate models and with scientistsstationed in EUMETSAT who are directly involved in producing and extending key satellite observing systems.The project will tackle some important questions including:- How much does upper tropospheric humidity amplify climate change?- Can state of the art climate models capture the processes determining variability and change in uppertropospheric humidity?- Will signatures from upper tropospheric humidity provide new insight into high altitude cloud feedbacks?- How does upper tropospheric humidity control Earth's radiative energy balance and is there a tropical supergreenhouse effect?The project will exploit existing data, numerical models and diagnostic tools and advance these systems to better interface Earth Observation and climate modelling as well as developing concepts relating to feedbacks processes that are fundamental for policy relevant quantitative climate science as listed below: - Exploitation of new satellite measurements of UTH.- Development of techniques to simulate consistent upper tropospheric humidity diagnostics in current climate models using existing software available from partners- How can upper tropospheric humidity measurements by combined synergistically with Earth radiation budget and water cycle measurementsThere will be opportunities to liaise and learn from EUMETSAT partners involved in developing UpperTropospheric Humidity datasets, the ESA Water Vapour Climate Change Initiative and the Met Office partnerson using and evaluating climate model simulations. This will provide comprehensive training in cross-disciplinary data analysis skills applied to models and Earth observations.