Evaluation of the WRF model on simulating the vertical structure and diurnal cycle of the atmospheric boundary layer over Bordj Badji Mokhtar (southwestern Algeria)

The assessment of desert dust and its transport in global atmosphere is highly influenced by the atmospheric boundary layer (ABL) structure and its time evolution over dust sources regions. In this paper, simulations were carried out using three widely used Planetary Boundary Layer (PBL) parameterizations in the Weather Research and Forecasting (WRF) model at the arid site of Bordj Badji Mokhtar, southwest Algeria (BBM, 21.38 degrees N, 0.93 degrees E, 420 m above sea level) characterized by its high dust emission potential. The main objectives were: (1) to investigate the structure and diurnal cycle of wind and temperature in the ABL (2) to evaluate and determine the PBL scheme suitable for mineral dust modelling in this region. Experiments were conducted under dry summer conditions on 08-13 June 2011 using three different PBL schemes: [Mellor-Yamada-Janjic (MYJ), Yonsei University (YSU) and Mellor-Yamada-Nakanishi-Niino (MYNN2)]. Predicted wind and temperature were validated against observed surface and upper air radiosonde data collected during a field measurement campaign undertaken at BBM in June 2011. It was found, that WRF model was able to reproduce the vertical structure and diurnal evolution of the dry ABL mainly during stability conditions. Among the three PBL schemes, WRF-MYNN2 PBL scheme performed better at surface level. However YSU scheme performed better in the ABL level with least errors and was the most suitable for this region. (C) 2017 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.