| In this paper,the high-resolution second-order sounding data from June 2014 to September 2017 is used to analyze the temporal and spatial distribution of buoyancy frequency and gravity fluctuation flux in East Asia,and Gaussian modeling of momentum flux in East Asia is better.Revealing the causes of the formation of the gravity wave source spectrum,the main conclusions are as follows:?1?The overall distribution of atmospheric brunt-vaisala frequency increases with height,the lower stratosphere is larger than the troposphere,and the buoyancy frequency remains constant in the troposphere and low stratosphere.The troposphere is 1.12*10-4s-2,low stratosphere.It is 5*10-4s-2.The buoyancy frequency in the troposphere is greatly affected by the topography,and the plateau region is a small value area,and gradually increases from west to east with the change of longitude;the buoyancy frequency in the low stratosphere is less affected by the topography,mainly with the latitude,the southern region Greater than the northern region.The buoyancy frequency in the troposphere?5-10km?and the low stratosphere does not change significantly with the season,and the seasonal variation of the troposphere to the stratosphere transition layer?10-18km?is larger;below 5km,the seasonal variation is obvious,and the winter change is the largest.The influence of the large terrain on the Qinghai-Tibet Plateau is weak in winter and strong in summer.The tropospheric buoyancy frequency is greater in winter than in summer,and the stratospheric buoyancy frequency is greater in winter than in winter;the buoyancy frequencies in the troposphere and low stratosphere at 18-19 km in the north and south have a one-year periodic change,and the northern region is the peak region in winter,and the southern region is 6-9.The month is the peak zone;at 18-19km,the small-value zone is from December to June.The change of the buoyancy frequency has a great influence on the gravity wave parameters.The second-level sounding data can grasp the changing characteristics of the atmosphere more accurately than the common air-test data,and reflect the state of the atmosphere.?2?In the vertical direction,the latitudinal momentum flux in the troposphere increases first and then decreases with the height.In the low stratosphere,the meridional momentum flux increases first and then decreases,and the latitudinal momentum flux decreases first.After the increase;the latitude and longitude momentum fluxes appear in the western part of the troposphere,the meridional momentum flux is the northward large value center,the latitudinal momentum flux is the westward large value center,in the low stratosphere The latitudinal and latitudinal momentum fluxes from west to east appear“fault”at 100-129°E;the latitudinal and latitudinal momentum fluxes vary little with latitude in the troposphere,and vary with latitude in the lower stratosphere.In the large-value center with a denser range,the meridional momentum flux appears to the south of the large value center in the low stratosphere,and the latitudinal momentum flux is the eastward large value center;the geographical distribution of the latitude and longitude momentum flux is:The momentum fluxes to the north and east of the troposphere dominate,and the momentum fluxes to the south and east in the low stratosphere dominate,and the influence of the large terrain of the Qinghai-Tibet Plateau on the troposphere is greater than that of the stratosphere.The latitude and longitude momentum flux in the vertical direction changes with height in winter compared with summer;the latitude and longitude momentum flux in the troposphere and stratosphere is more intense in winter than in other seasons;latitude and longitude momentum flux in the troposphere The change over time is not very obvious.In the low stratosphere,the latitude and longitude momentum fluxes show periodic changes with a period of one year,and winter is a large value area of??momentum fluxes to the south and west.?3?The peak of the troposphere winter is one order of magnitude larger than that of the low stratosphere,but the difference between the troposphere and the low stratosphere is not very large,indicating that the total tropospheric flux is greater than the low stratosphere,and the low stratosphere is intrinsic.The phase velocity is larger than the troposphere as a whole,which indicates that when the tropospheric gravity wave propagates through the jet stream and the low stratosphere,the jet stream absorbs and reflects part of the gravity wave,which results in the momentum flux in the low stratosphere being smaller than the momentum flux in the troposphere.For many reasons,the low stratospheric phase velocity is greater than the troposphere because the fluctuations in the wind travel,the background wind absorbs the fluctuations of the phase velocity,and only the phase velocity fluctuations can propagate to the lower stratosphere,so the low advection The phase velocity of the layer is greater than the troposphere. |
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