Central Asia – East Asia: High resolution climate modelling with a focus on mesoscale convective systems and associated precipitation over the Third Pole region

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The Third Pole (TP) is the Tibetan Plateau and all the mountain ranges that surround it. It has the world’s largest store of ice and snow outside the Arctic and Antarctic regions. The TP plays a significant role in the global climate system and is highly sensitive to humaninduced climate change. More than 10 major rivers originate from the TP, and the dramatic changes in the cryosphere have a great impact on water cycle, ecosystem and society over the TP and the surrounding regions. Due to the complex topography and harsh environment, ground-based observations are scarce over the TP, making the study of regional climate and its impact on other systems such as water and ecosystem difficult. Horizontal resolution of prevailing global reanalysis datasets is generally coarser than 30 km, which is not sufficient to examine convection and other mesoscale systems over the TP. High-resolution regional downscaling is badly needed for understanding processes and improve projections. This project aims at enhancing our understanding of the regional characteristics of water cycle changes over the TP region with a special focus on the convection and precipitation. The spatial scale of annual precipitation is generally small. Convection system contributes significantly to the total precipitation over the TP, and is therefore a key to understand the water cycle of the region. Thus, we will investigate the impact of convection system on the water cycle, especially precipitation. The contribution of Mesoscale Convective Systems (MCSs) to the precipitation over the TP will be addressed by using the Rain Cell Tracking method. A multi-model and/or multischeme approach will be utilized to assess the ability of regional climate model (RCM) in simulating convective precipitation over the TP, with the aid of satellite observations and water isotope observations. The targeted resolution is 2-9 km with a focus on convectionpermitting simulations (2-4 km). The simulations from different models or model configurations will be intercompared. We will start with a test simulation of one year. When this is done successfully, we plan to run a subset of models/model setups for a multi-year period between 1979 and 2018. The exact number of years will depend on the evaluation of the one year test and the computing resources available. The outcomes of the project are expected to enhance our understanding of processes relevant for cloud and precipitation formation, convection, MCS, and local wind system. They should also be useful to future high resolution regional climate modeling and regional reanalysis over the TP. Other studies, such as the water cycle will also benefit from the results of this project. An international was established for this project, including experts in regional climate modeling, relevant observation, statistical analysis, water isotope modeling and observations, as well as regional cryosphere and climate studies. Most of the teams have been actively engaged in or are in leading positions for an international research program the Third Pole Environment (TPE) which calls for such an effort. This project has a great potential to be successful and useful to WCRP in general and CORDEX in particular.