Arid Zone Research ›› 2021, Vol. 38 ›› Issue (1): 163-177.doi: 10.13866/j.azr.2021.01.18

• Weather and Climate • Previous Articles     Next Articles

Impact of boundary layer parameterization schemes on the simulation of a dust event over Northwest China

WEI Qian1(),LONG Xiao1(),ZHAO Jianhua2,HAN Zifei1,WANG Siyi1   

  1. 1. College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, Gansu, China
    2. Institute of Arid Meteorology, China Meteorological Administration, Lanzhou 730020, Gansu, China
  • Received:2020-04-27 Revised:2020-05-24 Online:2021-01-15 Published:2021-03-05
  • Contact: Xiao LONG E-mail:weiq17@lzu.edu.cn;longxiao@lzu.edu.cn

Abstract:

In this study, WRF-Chem(version 3.4) model was used to compare the performance of different Planetary Boundary Layer (PBL) parameterization namely, the YSU(Yonsei University), MYJ(Mellor-Yamada-Janjic), QNSE(Quasi-Normal Scale Elimination), MYNN2.5(Mellor-Yamada-Nakanisfii and Niino 2.5) and BouLac PBL schemes, over the dust event in northwest china on 27 March 2007. Surface observations were used for comparisons and evaluating model performance for meteorological variables. It is shown that simulations with the five PBL schemes can successfully reproduce the evolution of the dust event. The YSU and BouLac schemes produced higher surface friction velocity, 10 m wind speed, 2 m air temperature and surface PM10 concentration and lower 2-mrelative humidity, thus simulating stronger weather processes than those of the MYJ, QNSE and MYNN2.5 schemes. These results indicate that different boundary layer schemes affect the dust emission flux and PM10 concentration through different simulation effects of friction velocity. The dust emission flux and PM10 concentration tend to increase with higher friction velocity. Therefore, the dust event was enhanced due to the high friction velocity and the characteristics of high temperature as well as lower humidity in near-surface layer in the afternoon. As a result, the simulated dust event with the BouLac scheme was the strongest while the weakest by the QNSE scheme. Observations from Minqin meteorological station are used to validate the simulated results over Minqin region. Statistical analysis of the five simulations shows that the QNSE scheme simulated better PM10 concentration, the BouLac scheme performs well for 10 m wind speed and the YSU scheme resulted in the best model performance for simulating air temperature and relative humidity at 2 m. Overall, the YSU scheme was concluded as the best PBL scheme for the dust storm and the QNSE scheme was the worst one.

Key words: WRF-Chem, sand and dust, planetary boundary layer, numerical simulation