1:45 PM - 3:15 PM
[AAS08-P05] Simulation Case Study of the Evaporation Duct in Winter over South China Sea
Keywords:Evaporation Duct, SCSTIMX, WRF Model, PBL Scheme
The transmission path of electromagnetic waves will be changed due to variances in the physical properties of the atmosphere, affecting the performance of communication and radar equipment. The phenomenon that the atmospheric environment enhanced the distance of electromagnetic wave transmission is called the atmospheric duct. The method to determine atmospheric duct is analyzing the vertical variances of the modified refractive index in the atmosphere. Electromagnetic waves would be trapped in the atmospheric duct and could be transmitted a great distance. All kinds of atmospheric duct, especially the evaporation duct occurs in water areas frequently and worth to research.
In this study, analyzing the observation data of the 2017 South China Sea Twin-Island Monsoon Experiment (SCSTIMX), and three different planet boundary layer schemes were used to simulate and calculate the modified refractive index in the atmosphere, and determine the height of the evaporation duct. Compared with sounding data of the R/V OR1. The results of three different schemes are all underestimated. The reason for the lower evaporation duct is that the sea surface temperature is lower in the numerical model but the actual sea surface temperature is higher. Therefore, the calculation results of the inversion layer on the model ocean are also low, which makes the water vapor suppressed in the model near the sea surface, resulting in a low height of the evaporation duct. Comparing the results of three different PBL schemes, the MYJ scheme is more capable of presenting the temperature inversion and water vapor suppression in the lower atmosphere, thereby effectively simulating the process and mechanism of the evaporation duct.
In this study, analyzing the observation data of the 2017 South China Sea Twin-Island Monsoon Experiment (SCSTIMX), and three different planet boundary layer schemes were used to simulate and calculate the modified refractive index in the atmosphere, and determine the height of the evaporation duct. Compared with sounding data of the R/V OR1. The results of three different schemes are all underestimated. The reason for the lower evaporation duct is that the sea surface temperature is lower in the numerical model but the actual sea surface temperature is higher. Therefore, the calculation results of the inversion layer on the model ocean are also low, which makes the water vapor suppressed in the model near the sea surface, resulting in a low height of the evaporation duct. Comparing the results of three different PBL schemes, the MYJ scheme is more capable of presenting the temperature inversion and water vapor suppression in the lower atmosphere, thereby effectively simulating the process and mechanism of the evaporation duct.