Evaluation of planetary boundary layer schemes in WRF model for simulating sea-land breeze in Shanghai, China

The applicability of the planetary boundary layer (PBL) scheme in the WRF model varies in different regions due to the influences of topography, underlying surface, and atmospheric background. As a secondary circulation, when a sea-land breeze (SLB) process is simulated, the numerical result is very sensitive to the choice of the WRF PBL scheme. In the present study, the meteorological characteristics of a typical SLB event in Shanghai are simulated by employing eleven PBL schemes of the WRF model. The simulations are validated against the nearsurface meteorological data from five local meteorological stations as well as enhanced sounding observation data and then compared with the hourly near-surface meteorology during the SLB event. The results show that, except for the YSU, MYNN2.5, and SH schemes, the statistical values of the simulation results of the other schemes can only partially match the near-surface observations and sounding observation data. Although the statistical results of the MYNN2.5 scheme are consistent with the observational data, the results differ significantly from the hourly meteorological data during the occurrence of the SLB, which leads to a risk of overestimating the sea breeze intensity and consequently underestimating the inland temperature. Therefore, only the YSU and SH schemes are applicable to simulate the SLB in Shanghai. When the two schemes are applied to simulate the variations of sea breeze intensity and near-surface temperature, the results are in good agreement with the hourly observations from the coastal and inland meteorological stations. Moreover, YSU and SH schemes are appropriate for simulating the coupled structure of sea-land circulation and heat island circulation.

Automated summary

The applicability of the planetary boundary layer (PBL) scheme in the WRF model varies in different regions. The choice of the WRF PBL scheme is crucial when simulating a sea-land breeze (SLB) process. The study found that only the YSU and SH schemes are suitable for simulating SLB in Shanghai, as they provide accurate results and can simulate the coupled structure of sea-land circulation and heat island circulation.