| Based on the observation data of single station(Emeishan Station,Danka Station and Pailong Station)located on the Tibetan Plateau and its eastern edge area,the surface energy flux was calculated and the soil heat flux was estimated by temperature prediction-correction(TDEC).The characteristics of surface energy exchange in Emeishan area are analyzed and compared with the Qinghai-Tibetan Plateau.Also the changes of site surface heating field and precipitation is analyzed.Then the monthly mean surface heat flux in the European center and tropical precipitation data of TRMM 3b43 from 1998-2018 are used.Empirical Orthogonal Function(EOF)and Singular Value Decomposition(SVD)methods are used to analyze the temporal and spatial distribution characteristics of surface heat flux and precipitation in the Qinghai-Tibetan Plateau and its eastern margin,as well as the influence of surface heating on precipitation.The main results are as follows:(1)The sensible heat flux was positive in the daytime and negative at night on studied site of the Tibetan Plateau and its eastern edge area.The latent heat flux is positive all day.From November to May in Emeishan Station and Pailong Station, and from November to April in Danka Station,sensible heat is dominant in heat flux.The each component of surface radiation have a single peak in its diurnal variation.The peak value of shortwave radiation in Emei Mountain area appears around at 13:00,in Danka Station and Pailong Station appears around at 14:30.While the peak time of long wave radiation is later than that of short wave radiation.The diurnal variation of surface albedo appears to be"U"shape,and the winter surface albedo>spring>autumn>summer.Compared with the Danka and Pailong Station,there is a large surface albedo in the winter of Emeishan Station.(2)The phenomenon of non-closure-energy in three stations is very obvious,and the energy closure has a notable difference between day and night time.So surface soil heat storage has an important effect on energy balance at night.Energy closure rate in summer>autumn>spring>winter.When there is rainfall at night,the peak value of latent heat flux on the second day will be higher than that without rainfall,and the peak value of sensible heat flux will be lower.The abnormal closure point appears obviously in the rainfall period,and the range of energy balance ratio is obviously larger than other weather.Therefore,the rainfall has a great influence on the energy closure rate.(3)The annual average sensible heat flux in the Qinghai-Tibetan Plateau and its east side is positive,with an average of 33.73 w·m-2.It is characterized by large in the north and west,small in the south and east.The seasonal distribution is not consistent,the sensible heat flux in spring>summer>autumn>winter.The annual average latent heat flux is positive,with an average of 42.71 w·m-2.It is characterized by large in the south and east,small in the north and west.The seasonal distribution is consistent,the latent heat flux in summer>spring> autumn>winter.The annual average and seasonal distribution of precipitation are the same,with showing the characteristics of small in the northwest and large in the southeast.The average annual accumulated precipitation is 670.69 mm.(4)The sensible heat of the main body of the plateau and its east side and Sichuan Basin is negatively correlated with precipitation,that is,when the sensible heat flux of the main body of the plateau and its east side and Sichuan Basin is large(small),the local precipitation is less(more).There is a positive correlation between sensible heat flux and precipitation in Kunlun and Tanggula mountains. The latent heat of the main body of the plateau and its east side,Sichuan Basin is positively correlated with precipitation,that is,when the latent heat flux of the main body of the plateau and its east side,Sichuan Basin is large(small),the local precipitation is more(less).There is a negative correlation between latent heat flux and precipitation near Hengduan Mountain in the southeast of the plateau.The changing trend of sensible heat and latent heat fluxes in plateau is consistent with that of precipitation. |
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