The impact of planetary boundary layer parameterisation over the Yangtze River Delta region, China, part 1: meteorological simulation.

Zhu, Ansheng; Shi, Lishu; Huang, Ling; Gu, Ying; Wang, Yangjun; Chan, Andy; Li, Li

Abstract

The planetary boundary layer (PBL) is the main region for the exchange of matter, momentum, and energy between land and atmosphere. The transport processes in the PBL determine the distribution of temperature, water vapour, wind speed and other physical quantities and are very important for the simulation of the physical characteristics of the meteorology. Based on the two non-local (YSU, ACM2) and two local closure PBL schemes (MYJ, MYNN) in the Weather Research and Forecasting (WRF) model, seasonal and daily cycles of meteorological variables over the Yangtze River Delta (YRD) region are investigated. It is shown that all four PBL schemes overestimate 10-m wind speed and 2-m temperature, while underestimate relative humidity. Inter-comparisons among the different PBL schemes show that the MYNN scheme results in closer match of 2-m temperature and 10-m wind speed to surface observations in summer, while the MYJ scheme shows the smallest bias of 2-m temperature and relative humidity in winter. Compared to the observed PBL height obtained from a micro-pulse lidar system, the MYNN scheme exhibits lowest mean bias while the ACM2 scheme shows the highest correlation. It is also found that there is a varying degree of sensitivity of the PBL height in winter and summer, respectively; a best-performing PBL scheme should be chosen under different seasons to predict various meteorological conditions over complicated topography like the YRD region.

Citation

ZHU, A., SHI, L., HUANG, L., GU, Y., WANG, Y., CHAN, A. and LI, L. 2021. The impact of planetary boundary layer parameterisation over the Yangtze River Delta region, China, part 1: meteorological simulation. Preprint on Authorea [online]. April 20, 2021. Available from: https://doi.org/10.1002/essoar.10506840.1

• Publicly Available Date: Apr 7, 2023
• Keywords: Planetary boundary layer scheme; WRF; seasonal sensitivity; Yangtze River Delta
• Public URL: https://rgu-repository.worktribe.com/output/1888453