Mesoscale Numerical Simulation Of Evaporation Duct In The South China Sea Based On WRF

Atmospheric duct environment changes the normal propagation path and range of electromagnetic wave,and has important influence on radar detection and radio communication.Especially,evaporation duct has the highest occurrence compared to other types of atmospheric duct over sea.And it has the greatest impact on radar detection system on naval ships and along the shore.Fully utilizing and effectively avoiding evaporation duct effect has become the focus of national defense all over the world,so it is very necessary to study evaporation duct.Based on a new mesoscale atmospheric numerical model WRF and coupled with the evaporation duct diagnostic model NPS at sea,a numerical simulation system for evaporation duct at sea is developed.Among them,the NPS model is used to solve the problem that the resolution of the underlying data in the vertical direction is insufficient.The numerical simulation system was used to simulate the evaporation duct in the designated area and time of the South China Sea.And Numerical simulation results are compared,analyzed and validated by the experimental sounding data of the evaporation duct detection system built in the South China Sea and other statistical results.Specific work includes the following points:(1)In order to obtain the actual atmospheric correction refractive index profile and atmospheric duct characteristic parameters in the South China Sea,an evaporation duct detection system(experiment platform)was built in the South China Sea.A large number of measured meteorological data were collected and stored,which provides a guarantee for the subsequent analysis and verification of numerical simulation.The basic principle of the diagnostic model of the evaporation duct is studied,and the diagnosis process of the NPS model used in this paper is mainly deduced,and the diagnosis and error analysis are carried out.(2)The working principle of atmospheric numerical model and the composition module of WRF model and its implementation process are studied.Then,a preliminary framework of atmospheric duct numerical simulation system is proposed.On the local Linux server,an evaporation duct numerical simulation system based on WRF mode and coupled with NPS model is built and installed.A sample numerical simulation experiment was carried out to verify the correctness of the WRF model development environment.(3)The evaporation duct process over the South China Sea from November 1,2014 to 5(5 days)is simulated numerically with the new numerical simulation system respectively.The simulation results are compared with tower observation data,and the results fit well and have a basically consistent variation.The average error of evaporation duct height of the 5 days is 1.289 m.Besides,the numerical simulation system is used to simulate the evaporation duct over the South China Sea during the whole year of 2011.Spatial-temporal features of evaporation duct for 12 months are statistically analyzed and the conclusion of the analysis is consistent with the conclusions of other literatures.The experiment proves the reliability and feasibility of the new evaporation duct numerical simulation system proposed in this paper.Numerical simulation of mesoscale evaporation duct is realized,which provides a theoretical reference and practical basis for further research on numerical simulation and prediction of ocean evaporation duct.