A 5 km Resolution Regional Climate Simulation for Central Europe: Performance in High Mountain Areas and Seasonal, Regional and Elevation-Dependent Variations

Abstract

Mountain regions with complex orography are a particular challenge for regional climate simulations. High spatial resolution is required to account for the high spatial variability in meteorological conditions. This study presents a very high-resolution regional climate simulation (5 km) using the Weather Research and Forecasting Model (WRF) for the central part of Europe including the Alps. Global boundaries are dynamically downscaled for the historical period 1980–2009 (ERA-Interim and MPI-ESM), and for the near future period 2020–2049 (MPI-ESM, scenario RCP4.5). Model results are compared to gridded observation datasets and to data from a dense meteorological station network in the Berchtesgaden Alps (Germany). Averaged for the Alps, the mean bias in temperature is about −0.3 °C, whereas precipitation is overestimated by +14% to +19%. R 2 values for hourly, daily and monthly temperature range between 0.71 and 0.99. Temporal precipitation dynamics are well reproduced at daily and monthly scales (R 2 between 0.36 and 0.85), but are not well captured at hourly scale. The spatial patterns, seasonal distributions, and elevation-dependencies of the climate change signals are investigated. Mean warming in Central Europe exhibits a temperature increase between 0.44 °C and 1.59 °C and is strongest in winter and spring. An elevation-dependent warming is found for different specific regions and seasons, but is absent in others. Annual precipitation changes between −4% and +25% in Central Europe. The change signals for humidity, wind speed, and incoming short-wave radiation are small, but they show distinct spatial and elevation-dependent patterns. On large-scale spatial and temporal averages, the presented 5 km RCM setup has in general similar biases as EURO-CORDEX simulations, but it shows very good model performance at the regional and local scale for daily meteorology, and, apart from wind-speed and precipitation, even for hourly values.

Management Intensity Controls Nitrogen-Use-Efficiency and Flows in Grasslands—A 15N Tracing Experiment

“…• 07 E, herein referred to as low elevation "LE"), is characterized by a MAT of 8.9 • C and 956 mm MAP and was used to simulate climate change conditions for intact lysimeters translocated within a space-for-time approach from Graswang to the Fendt site. This climate change treatment represents projected temperature increases of +2 • C and summer precipitation reduction as projected by regional climate modeling of the mid-21st century [12][13][14][15][16]. However, it does not include free air CO 2 enrichment.…”

“…Samples were transported to the facilities of KIT/IMK-IFU in Garmisch-Partenkirchen, Germany for further processing and analysis. Plant biomass yield and N export was measured during 2012-2017, while analysis of 15 N recovery was only conducted during labeling with 15 N enriched slurry in 2017.…”

“…where N pool is the amount of N in mg in the plant or depth-specific soil N pool and (atomic percent excess) APE is the 15 All results were scaled to the lysimeters by multiplying the calculated 15 N excess (mg kg −1 sdw) by the respective sdw (kg) of the lysimeter layer sampled. Tracer recovery in AGB was always calculated with cumulated 15 N excess, thereby accounting for the previously exported 15 N excess across multiple seasonal biomass harvests.…”

“…With climate warming, biomass production of grasslands in the alpine and pre-alpine region may increase [9,10], thus enabling farmers to achieve higher yields and to expand the intensive management from the lowlands into montane regions. This is of special interest in the European alpine and pre-alpine regions, where climate warming is occurring at twice the rate compared to global average, a trend, projected to continue during the next decades [11][12][13][14][15]. Changes in seasonal precipitation and in precipitation extremes are also expected, but the direction and magnitude of effects in the Alps may vary strongly across regions and elevation [12,[14][15][16][17].…”

“…Earlier studies have indicated that climate change in the alpine and pre-alpine grassland region could lead to SOC loss [2] and nitrogen (N) mining (when N export exceeds input causing a depletion of soil N) from extensively managed grassland soils [19]. This is mainly activated by increased mineralization of soil organic matter (SOM) and associated liberation of nutrients, thereby stimulating both N losses and grassland productivity [2,15,20]. This can be relevant for the overall N balance because harvest export is the dominant N loss pathway in montane grasslands [21].…”