The question of how sensitive the regional and local climates are to
different land cover maps and fractions is important, as land cover
affects the atmospheric circulation via its influence on heat, moisture,
and momentum transfer, as well as the chemical composition of the
atmosphere. In this study, we used three independent land cover data
sets, GlobCover 2009, GLC2000 and ESACCI-LC, as the lower boundary of
the regional climate model COSMO-CLM (Consortium for Small Scale
Modeling in Climate Mode, v5.0-clm15) to perform convection-permitting
regional climate simulations over the large part of Europe covering the
years 1999 and 2000 at a 0.0275° horizontal resolution. We studied how
the sensitivity of the impacts on regional and local climates is
represented by different land cover maps and fractions, especially
between warm (summer) and cold (winter) seasons. We show that the
simulated regional climate is sensitive to different land cover maps and
fractions. The simulated temperature and observational data are
generally in good agreement, though with differences between the
seasons. In comparison to winter, the summer simulations are more
heterogeneous across the study region. The largest deviation is found
for the alpine area (−3 to +3 °C), which might be among different
reasons due to different classification systems in land cover maps and
orographical aspects in the COSMO-CLM model. The leaf area index and
plant cover also showed different responses based on various land cover
types, especially over the area with high vegetation coverage. While
relating the differences of land cover fractions and the COSMO-CLM
simulation results (the leaf area index, and plant coverage)
respectively, the differences in land cover fractions did not
necessarily lead to corresponding bias in the simulation results. We
finally provide a comparative analysis of how sensitive the simulation
outputs (temperature, leaf area index, plant cover) are related to
different land cover maps and fractions. The different regional
representations of COSMO-CLM indicate that the soil moisture,
atmospheric circulation, evaporative demand, elevation, and snow cover
schemes need to be considered in the regional climate simulation with a
high horizontal resolution.