The Change Characteristics And Effect Factors Of The Heat Source And Moisture Sink Over The Tibetan Plateau

The thermal-dynamical effects and moisture transport over the Tibetan Plateau have significant impacts on the atmospheric circulation and climate change not only within the Asian region but also across the world.The vertically integrated apparent heat source(?Q₁?)and apparent moisture sink(?Q₂?)can reflect features and evolutions of heat and moisture budgets.In this study,we focus on the variation of?Q₁?and?Q₂?over the Tibetan Plateau from 1980 to 2017 by analyzing JRA-55.And investigate the impact of internal climate variability modes such as the El Ni?o-Southern Oscillation(ENSO)and North Atlantic Oscillation(NAO)on?Q₁?and?Q₂?over the Tibetan Plateau on the different time scales.We also analyze the differences between the CMIP6 historical simulation result and reanalysis data,and make corrections to the simulation result.Finally,we employ the correlated CMIP6models to analyze the future variability of Decadal Modulated Oscillations(DMOs)of?Q₁?and?Q₂?under different emission scenarios in CMIP6 future predicted data.The main conclusions are as follows:(1)During the period of 1980-2017,the variations of seasonal?Q₁?and?Q₂?over the Tibetan Plateau were different,especially in winter.The wavelet analysis results indicated that the characteristics of the winter?Q₁?and?Q₂?on the decadal time scales were continuous with the most obvious fluctuations,and the main period of?Q₁?and?Q₂?is 12 year and 20 year,respectively.(2)The impact of ENSO and NAO indices on the?Q₁?and?Q₂?over the Tibetan Plateau is small on the inter-annual time scales,but the most significant correlation occurs at the decadal time scales.The composite analysis revealed that positive and negative phase transition of ENSO and NAO indices has a significant effect on the spatial distribution of?Q₁?and?Q₂?over the Tibetan Plateau on the decadal time scales.(3)The CMIP6 historical simulation didn't reproduce the main characteristics of the trend of annual?Q₁?and?Q₂?over the Tibetan Plateau and couldn't simulate the inter-annual components accurately,comparing with reanalysis data.So we selected the models that can simulate the DMOs of?Q₁?and?Q₂?over the Tibetan Plateau correctly,and found that the oscillation periods of the ensemble mean of DMOs from these correlated CMIP6 models will be shorten with the intensification of emission scenarios.