Simulation Of Dynamic Downscaling Of Meteorological Elements In Southwest China

Meteorological service products are derived from historical meteorological data,and the existing historical aviation meteorological data are mostly derived from civil aviation ground meteorological observations,but these traditional historical meteorological data have greater limitations.Most historical civil aviation meteorological data are site data and time The spatial resolution is low,and it is difficult to meet the demand development of civil aviation meteorological service products.The civil aviation industry in Southwest my country is developed,but the terrain is complex and the climate is complex and changeable.Through the dynamic downscaling method,a set of high-quality,refined,and high temporal and spatial resolution historical meteorological element data sets that conform to the climate characteristics of the Southwest region are obtained.The development of regional aviation meteorological services plays a vital role.This thesis firstly explores the simulation capability of dynamic downscaling based on the WRF model by simulating the near-surface 10 m wind speed and surface 2m temperature in the southwest in July 2019,and compares and analyzes16 different planetary boundary layer and near-surface parameter schemes for southwest China.In the research on the simulation of regional meteorological elements,select the combination of parameter schemes that can better describe different meteorological elements to downscale the same month,analyze and compare the effects of the spectral approximation scheme and the SST update scheme on the downscaling simulation ability,and finally select the one with better description.The combination of the test scheme conducts downscaling simulations in the southwest region from 2016 to 2018,and explores the geospatial field of precipitation,near-surface 10 m wind,and 2m temperature,and the monthly and hourly results verification analysis.The main conclusions are as follows:1)The low wind speed simulation value of the WRF model in the Sichuan-Chongqing area is too large,and the high wind speed simulation value is small,and the simulation effect of the basin plain area is better than that of the edge of the mountain basin.The wind speed in the geospatial field in the southwest region presents two high-value areas,Chongqing Mountain,Foshan,and Guizhou Weining,and these two areas present low-value areas at the temperature of 2 m near the ground.In terms of planetary boundary layer scheme selection,ACM2 and YSU schemes have better description effect on near-surface wind speed and temperature in southwest China.2)Under the premise that the parameters of the planetary boundary layer and the near-surface layer are kept unchanged,3km and 9km do not show better simulation results than 27 km,but each scheme shows better results on the basis of improved resolution.The phenomenon that the wind speed is simulated increases,among which the MYJ scheme and the TEMF scheme show obvious performance.Hourly precipitation and 2m near-surface temperature did not show significant differences at different horizontal resolutions.Overall,higher model resolution does not show obvious advantages in dynamic downscaling of meteorological elements in southwest China.3)Whether the spectral approximation option is turned on more affects the model value of the precipitation deviation center.After the model resolution is improved,the average deviation of the western mountainous area increases;the SST update has little effect on the model value distribution of the simulated near-surface wind speed in the southwest region.,and only opening the spectral approximation scheme of spectral approximation uv variables above 750 hpa will have a greater impact on the distribution of model values.After the model resolution increases,the wind speed simulation value increases.When the wind speed is large,it is recommended to use a higher spatial resolution;The temperature deviation in the western mountainous area exceeds 2 °C,the model simulation temperature is too small,and the simulation effect is poor.The average deviation in the basin is-0.2 °C,and the overall model simulation value in the basin is higher than the observed value.Spectral approximation,SST update,and model resolution There is no significant optimization for the simulation effect of dynamic downscaling temperature in southwest China.4)The analysis of the meteorological element data set reconstructed by the dynamic downscaling method in the southwest region shows that the southwest region has less precipitation in winter and less precipitation in summer but frequent precipitation.Although the spatial field distribution information of precipitation is simulated,the overall simulation effect is not good.Good;the large value of wind speed in winter mainly occurs near Weining Observation Station in Guizhou and the mountainous areas in western Sichuan.In summer,the large value area shifts from Weining area in Guizhou to the southeast area.The overall wind speed is lower than that in winter.At about 1.6m/s,the model has a small simulation value for the large wind speed area and a large simulation value when the wind speed is small;the simulation effect of the two-meter temperature space field on the ground in the southwest region is the best,but it still retains the characteristics of poor downscaling effect in the west.The simulated temperature is much lower than the actual temperature.The average deviation of the simulation effect in the eastern basin plain is only 1°C,and the root mean square error is only ±1°C,which can meet the requirements in winter and summer.