Heatwave Simulations with WRF - BEP - BEM: Why Are Simulated Wind Speeds So Erratic While Station Observations Are Smooth?

[luyixiao]

I'm currently using the WRF - BEP - BEM model to simulate heatwave events in my study area. However, I've encountered a puzzling issue regarding 10m wind speed. The simulated wind speeds exhibit extremely violent fluctuations, whereas the observational data from meteorological stations are relatively smooth.

I've attached a graph for your reference, which clearly shows the stark contrast between the two. The red line representing the simulated wind speed has large and frequent spikes, while the blue line of the observational data varies in a much more stable manner.

Has anyone else faced a similar issue when using the WRF - BEP - BEM model for heatwave simulations? Any suggestions on diagnosing and solving these problems, especially improving the model's performance regarding the wind speed fluctuations and the low 2m air temperature, would be greatly appreciated. Thank you!

 

[cenlinhe]

Are you using the urban parameters from table values or an input 2-D map? You may want to improve/tune urban parameters to increase building height or plan area index or surface roughness length parameters to reduce wind speed (which may give you smoother wind timeseries). You may also want to test changing your PBL physics option.

 

[luyixiao]

Thank you! Based on your suggestions, I found some defects in my static geographic data. I used the GloUCP dataset provided by Liao et al., and the paper link is GloUCP: A global 1 km spatially continuous urban canopy parameters for the WRF model. When I used ncview to check the URB_FRC2D variable and URB_PARAM variable in my geo_em.nc file, although the displayed value range is 0-51.2891, the values within my domain are almost all 0. I'm looking forward to your any suggestions for this situation.

 

[cenlinhe]

There may be some issues with your method of using the GloUCP data in WPS. If you have zero FRC_URB2D, the model will use urban parameter table values for urban grids.