Analysis Of Environmental Characteristics Of Tropical Cyclones And Sensible Heat

The low vortex on the plateau is the main weather system that causes precipitation in the plateau and its surrounding areas in the east.It is of great scientific significance to master the rules and changes of its activities.This paper mainly analyzes the relationship between the low vortex system of the Qinghai-Tibet Plateau and the plateau surface sensible heat in summer.According to the definition of plateau low vortex,the grid points that meet the conditions are counted,and their climatic characteristics are analyzed.The statistical analysis of the surface sensible heat on the plateau was calculated using the overall transport method of sensible heat flux,using ERA-INTERIM reanalysis data of 1 ° × 1 ° from 1979 to 2015 and70 conventional meteorological stations on the Qinghai-Tibet Plateau from1982 to 2012.Ground observation data,and calculated daily data of surface heat.The basic climatic characteristics of surface sensible heat on the Tibetan Plateau are discussed and analyzed.The empirical orthogonal function decomposition(EOF)was used to obtain the sensible heat flux,and the time series of the first two modalities were taken at the same time,and then the correlation between the low vortex activity of the Qinghai-Tibet Plateau and the surface sensible heat flux in summer was discussed.The influence of the special terrain of the Qinghai-Tibet Plateau on the vertical shear of wind speed is reflected by the change of low vortex on the plateau.For tropical cyclones with similar structure,wind shear is also one of its environmental field factors.Explore analysis.The occurrence of climate change in recent years has significantly increased the intensity of frequent tropical cyclones.Studying the impact of climate change on the tropical cyclone environmental field is of great scientific significance for estimating the meteorological disasters it brings,and it is important for future shipping and landing The socio-economic impact of the economy is wide.The reduction of vertical wind shear and the increase of water vapor in global warming are invariant in different climate models and greenhouse gas emission schemes,but the sea surface temperature pattern has a significant impact on atmospheric circulation and sea surface precipitation changes.The diversity of sea surface temperature among models should be very important to the uncertainty of tropical cyclone environment change.In this paper,a multi-model ensemble analysis is used to compare wind speeds by establishing a dynamic factor decomposition method that takes wind speed vertical shear and sea surface temperature change patterns asrepresentative parameters,and uses data from the Intergovernmental Climate Change Commission's Coupled Climate Model Comparison Project(CMIP5).Effects of weakened vertical shear and elevated sea surface temperature on tropical cyclone environmental fields.Two kinds of indexes are mainly used for exploration: Maximum Potential Intensity(MPI),which represents the maximum potential development intensity of tropical cyclones and Genesis Potential Index(GPI),and the possibility of cyclones.The following conclusions were reached:(1)The number of low vortexes on the plateau in summer has been increasing year by year,and the number of low vortexes on the plateau has increased significantly since the 1990 s.Compared with the three months in summer,the surface temperature is higher in July,and the atmospheric circulation over the area is mostly an anticyclonic wind field,which is beneficial to the formation of low vortices.The second is the second,and the surface temperature in June is relatively low,and the atmospheric circulation is mostly cyclonic,which is not conducive to the formation of low plateau vortices,and the number is the smallest.In summer,low-vortex generation sources in the plateau are mainly concentrated in Yushu Prefecture of Qinghai Province,Golmud region of Qinghai Province,and Nagqu region of Tibet.A few low-vortex generation sources in the easternpart of the plateau tend to move south with time.(2)The sensible heat in the western part of the Qinghai-Tibet Plateau is stronger than the sensible heat in the east.In addition,the sensible heat flux in the three months of summer has been decreasing year by year.The average sensible heat value in June is the highest,and it decreases in July and August.(3)The first mode of temporal and spatial distribution of summer sensation in the Qinghai-Tibet Plateau is a north-south inversion.Before the 1990 s,the sensation in the plateau was strong in the south and weak in the north,and after the 1990 s,the heat was strong in the south and weak in the north.The temporal and spatial distribution of the second mode of sensible heat in the plateau in summer is the east-west inversion type.Before 2003,it was mainly the west-strong east-weak type,and after 2003 it was mainly the west-weak east-strong type.There is a significant negative correlation between the first modal time series of sensible heat in the Qinghai-Tibet Plateau in summer and the number of low vortices generated on the plateau.(4)When the surface sensible heat flux on the Qinghai-Tibet Plateau increases in summer,the number of low-vortex generation on the plateau decreases,and when the sensible heat weakens,the number of low-vortex generation on the plateau increases.In summer,the number of low vorticesgenerated on the plateau is high(less),which has a good correspondence(negative correlation).When the sensible heat flux is strong,the surface temperature rises,and the high-altitude negative potential vorticity will correspond to the occurrence of an anticyclonic wind field.This wind field is not conducive to the generation of low vorticity on the plateau,the sensible heat is weak,and the surface temperature decreases.The corresponding high-altitude potential vorticity is the positive potential vorticity anomaly.The center of the high-altitude positive potential vorticity anomaly and the surrounding area will correspond to a cyclonic wind field,which is conducive to the generation of low plateau vortices.(5)Calculate the MPI and GPI indices,and conduct partial deduction for the sea surface temperature and vertical wind speed shear in the formula respectively to obtain the main dynamic factors of tropical cyclones affected by the environment.The formula of the maximum potential development intensity index of tropical cyclones shows that the calculation results are mainly related to sea surface temperature,and the possibility index of tropical cyclone occurrence also takes into account the vertical shear of wind speed.(6)Sea surface temperature-related changes will be closer to MPI in both the ensemble average and the mode.The uncertainty of sea surface temperature is mainly manifested in the difference between summer andwinter,and the difference between different sea areas.Anomalies in sea surface temperature can cause changes in environmental factors such as vertical wind speed shear and relative humidity,thereby causing the greatest potential for tropical cyclones.The development intensity and the possibility of a cyclone change.Sea surface temperature has a positive correlation with the maximum potential development intensity,and vertical shear of wind speed has a negative correlation with the possibility of cyclones.