Influence of land cover on lightning and convective precipitation over the European continent

Abstract

The impact of land cover on lightning and convective precipitation in the summertime over Europe was analysed using five-year data. Lightning data were obtained with the Optical Transient Detector (OTD) at a 0.5° × 0.5° spatial resolution and the convective precipitation data were calculated by the NCEP/DOE AMIP-II Reanalysis at a ∼1.9° × 1.9° spatial resolution. Data concerning land cover were obtained from the Global Land Cover Facility, although the original 14 categories were grouped into seven categories (water, forest, shrubland, grassland, cropland, bare ground and urban). For all latitude ranges, forested areas tend to increase convective activity during the warm period of the year, and the general effect of shrubland areas is to suppress convective activity. The behaviour of convection in relation to grasslands and croplands depends on latitude. At low latitudes both vegetation types tend to increase convection during the summer. At high latitudes, grassland and cropland areas appear to be associated with the opposite effect in relation to convection: grass suppresses and crops enhance it. Finally, bare soil tends to decrease convective activity. These results seem to be related to the impact of vegetation on soil moisture and roughness. In general, vegetation areas associated with high soil moisture contents and high values in roughness length tend to enhance convective activity.