Updated vegetation information in high resolution regional climate simulations using WRF

Climate studies show that the frequency of heat wave events and above-average high temperatures during the summer months over Europe will increase in the coming decades. Such climatic changes and long-term meteorological conditions will impact the seasonal development of vegetation and ultimately modify the energy distribution at the land surface. In weather and climate models it is important to represent the vegetation variability accurately to obtain reliable results. The weather research and forecasting (WRF) model uses a green vegetation fraction (GVF) climatology to represent the seasonal variation of vegetation parameters. The climatology describes the fractional vegetation cover within each grid cell but is additionally used to scale other parameters such as LAI, roughness, emissivity and albedo within predefined intervals. The climatology does not reflect recent climatic changes or changes in management practice since it is derived more than twenty years ago. In this study, a new high resolution, high quality GVF product is applied in a WRF climate simulation over Denmark during the 2006 heat wave year. The new GVF product reflects the year 2006 and it was previously tested in a climate run at low spatial resolution showing good performance. The new simulations are carried out at higher resolution and the performance is quantified against (1) a control run using the default GVF data and (2) two gridded data sets (E-OBS and DMI Climate grid) at lower resolution for which the simulations are aggregated to match the resolutions of the gridded data. The comparison include temperature, wind and precipitation