The influence of local land use on the local weather

Abstract

Change of land use may be an important tool in mitigating future climate extremes. Studies in the past have shown that deforestation in the tropics has led to a decrease in precipitation, but there is less evidence that such an effect exists in the Netherlands, on a smaller scale. In order to explore the possibilities of this, simulations with the regional climate model HCLIM from 2018-2022 are performed in which the input files for land use, ECOCLIMAP-SG, are manipulated. Within a square around the Dutch province Limburg, all vegetation types are set to either temperate deciduous broadleaf, temperate evergreen needleleaf, or kept the same. A resulting difference is more average precipitation in Limburg in winter in the forest experiments, which is explained by effects associated with the higher roughness length for trees in comparison to low vegetation. In addition, a case study of August 2019 shows higher precipitation values for two precipitation events in the forest simulations, compared to the control simulation. This difference may be explained by a higher sensible heat flux in the forest simulations in the days before these precipitation events. Furthermore, it is found that also the yearly average latent heat flux is smaller over Limburg in the forest experiments. Three additional simulations indicate that the chosen values for the minimal stomatal resistance in HCLIM may be partly, but cannot be solely responsible for the difference in latent heat flux.