The Variability Of Atmosphere Heat Source Over The Tibetan Plateau And Its Influences On The Circumglobal Teleconnection In The Northern Hemisphere Summer

The diabatic heating of the Tibetan Plateau(TP)has an important influence on northern hemisphere weather and climate.However,the uncertainty of long-term reanalysis or satellite radiation products restricts the study of spatiotemporal variation of TP heating.This paper uses station observation to assess 4 satellite radiation products,analyse the applicability of satellite radiation products over the TP and the causes of the error,and then establish a long-term fusion radiation product which reflect the TP radiation characteristics correctly.Based on the reanalysis and AGCM,the vertical structure of the TP heating and it's influence on the circulation global teleconnection(CGT)are explored.The results are as follows:(1)The deviations of radiation flux climatology are within 5% during 1984-2017.FH radiation fluxes are properly increasing in winter,the trends of downward shortwave(SWD)and upward longwave(LWU)is contrary to observation.Air temperature error would overestimate FH's downward(LWD)climatology and trend,and the influence of surface temperature to LWU is opposite.The radiation model,cloud and moisture differences may result in appreciable underestimation of LWD,while the calculation process of FH partly corrects the underestimation of LWU.The fusion radiation product established in this paper make up for the deficiency of FH and other satellite radiation product,and performance longterm variation and linear trend of radiation fluxes over the TP correctly.(2)The temperature difference between surface and air impacts the spatial distribution of sensitive heat(SH)over the TP.SH is strong(weak)over southeast-TP and weak(strong)over northwest-TP in winter(summer).The wind speed and temperature difference between surface and air are weak from early-1970 s to late-1990 s,and begin to increase in the early-20 th.Concurrently influenced by temperature difference and wind speed,the interdecadal variation of SH over the TP from 1961 to 2017 is increasing-decreasing-increasing,and the two interdecadal abrupt change occur in 1975 and 1999,respectively.Q1 significantly weaken before 2000,since the net radiation of air column(RC),SH and latent heat(LH)consistently weaken.However,the increasing Q1 slowdown in the 20 th.(3)The heating rate of WTP decreases with the increase of height.In the same pressure layer,the intensity and variability of atmospheric heating on the main TP are stronger than that on the southwest side of the TP.Accordingly,a strong heat source is formed in the middle and upper troposphere over the main TP.The CGT,represented by the second EOF mode of 200 h Pa potential height field in the northern hemisphere,is enhanced when the WTP Q1 is stronger.We call the relationship between the two factors as TP-CGT teleconnection.Two energy transmission tracks of WTP diabatic heating are investigated,the firstly is eastward through the westerly jet,the other is eastward by the Gill type Rossby wave which enhanced by the WTP diabatic heating anomaly,the transmission of energy from WTP to adjacent CGT nodes would take 1-7 days.CGT is an internal mode of the atmosphere circulation,but the influence of LH variation over the WTP on the CGT is up to 18%.