Sensitivity Study of Simulations of Two Fog Events at Ardebil Airport to the PBL Scheme, Using WRF model

In this study, numerical simulation of two advection and radiation fog events at Ardabil Airport in January 2015 was performed using the Weather Research and Forecasting (WRF) model and SW99 visibility algorithm. Six Planetary Boundary Layer (PBL) schemes including YSU, MYJ, ACM2, MYNN2.5, MYNN3 and QNSE were used to evaluate the sensitivity of fog simulation to the PBL schemes. The results show that the simulation of these two fog events is sensitive to PBL. Also, due to the importance of accurate prediction of 2-m relative humidity, temperature and dew point temperature and 10-m wind speed in fog forecasting, the sensitivity of simulation of these variables to PBL scheme was investigated. The results showed that the simulation of advection fog event was successfully performed using most of PBL schemes mentioned above. YSU, ACM2 and MYNN2.5 schemes performed better in simulation of advection fog. The QNSE scheme was not successful in simulating the advection fog event. In radiant fog simulation, most PBL schemas were not able to simulate the moisture required to form fog at the time of fog occurrence.Most PBL schemes were not able to simulate the moisture required for formation of fog at the time of the radiation fog event. A few hours before the onset of the radiation fog event, the WRF model with most schemes simulated the visibility reduction due to the fog. Generally, QNSE and MYJ schemes performed worse than other schemes in simulating temperature, dew point temperature, relative humidity and wind speed.