K Goergen, J Junk, JJ Beersma, L Pfister, L Hoffmann

This study assesses projected future regional climate changes in the G. D. of Luxembourg based on a six-member RCM ensemble from the EU ENSEMBLES project with a focus on air temperature and precipitation and the impacts of those changes on vegetation. The motivation lies in the facts that although publications exist on observed changes indicating rising minimum and maximum temperatures and precipitation amounts and despite there are numerous regional climate change studies for Central Europe, there seems to be no study on future changes specifically for Luxembourg; and secondly as agriculture is the dominant land use in Luxembourg possible effects on crops and more general vegetation are relevant. Five different RCMs at 25 km spatial and a daily temporal resolution, ranging from 1961 to 2100 dynamically downscale three different GCMs, based on the SRES A1B emission scenario. To reduce systematic biases in the RCM-derived time-series, a bias correction is applied. Multi-model annual mean temperatures are projected to rise by 3.1°C between the control time-span (1961 to 1990) and the far future (2071 to 2100). Clear change signals are also found in seasonal bivariate frequency distributions of air temperature and precipitation. These changes’ impacts are an elongation of the thermal vegetation period by 6.2 days per decade due to an earlier onset in spring. Growing degree-day sums show a substantial increase leading to potentially better growth conditions. Albeit the earlier onset of the vegetation period causes also a clear increase in late frost risk, especially in the near future (2021 to 2050) projections. Within the vegetation period also the number of dry spell events and days increases by about 55%. At the same time the number of heavy precipitation events is nearly doubled.

Bibliographic data

K Goergen, J Junk, JJ Beersma, L Pfister, L Hoffmann. DEZE MAG WEG!
Status: submitted, Journal: Meteor. Z., Year: 2010