Journal Article
The first multi-model ensemble of regional climate simulations at kilometer-scale resolution, part I: evaluation of precipitation
Nikolina Ban; Cécile Caillaud; Erika Coppola; Emanuela Pichelli; Stefan Sobolowski; Marianna Adinolfi; Bodo Ahrens; Antoinette Alias; Ivonne Anders; Sophie Bastin; Danijel Belušić; Ségolène Berthou; Erwan Brisson; Rita M. Cardoso; Steven C. Chan; Ole Bøssing Christensen; Jesús Fernández; Lluís Fita; Thomas Frisius; Goran Gašparac; Filippo Giorgi; Klaus Goergen; Jan Erik Haugen; Øivind Hodnebrog; Stergios Kartsios; Eleni Katragkou; Elizabeth J. Kendon; Klaus Keuler; Alvaro Lavin-Gullon; Geert Lenderink; David Leutwyler; Torge Lorenz; Douglas Maraun; Paola Mercogliano; Josipa Milovac; Hans-Juergen Panitz; Mario Raffa; Armelle Reca Remedio; Christoph Schär; Pedro M. M Soares; Lidija Srnec; Birthe Marie Steensen; Paolo Stocchi; Merja H. Tölle; Heimo Truhetz; Jesus Vergara-Temprado; Hylke de Vries; Kirsten Warrach-Sagi; Volker Wulfmeyer; Mar Janne Zander
Climate Dynamics · Vol. 57, Issue 1-2 · pp. 275-302 · 2021
Abstract
Here we present the first multi-model ensemble of regional climate simulations at kilometer-scale horizontal grid spacing over a decade long period. A total of 23 simulations run with a horizontal grid spacing of $$\sim $$ ∼ 3 km, driven by ERA-Interim reanalysis, and performed by 22 European research groups are analysed. Six different regional climate models (RCMs) are represented in the ensemble. The simulations are compared against available high-resolution precipitation observations and coarse resolution ( $$\sim $$ ∼ 12 km) RCMs with parameterized convection. The model simulations and observations are compared with respect to mean precipitation, precipitation intensity and frequency, and heavy precipitation on daily and hourly timescales in different seasons. The results show that kilometer-scale models produce a more realistic representation of precipitation than the coarse resolution RCMs. The most significant improvements are found for heavy precipitation and precipitation frequency on both daily and hourly time scales in the summer season. In general, kilometer-scale models tend to produce more intense precipitation and reduced wet-hour frequency compared to coarse resolution models. On average, the multi-model mean shows a reduction of bias from $$\sim \,$$ ∼ −40% at 12 km to $$\sim \,$$ ∼ −3% at 3 km for heavy hourly precipitation in summer. Furthermore, the uncertainty ranges i.e. the variability between the models for wet hour frequency is reduced by half with the use of kilometer-scale models. Although differences between the model simulations at the kilometer-scale and observations still exist, it is evident that these simulations are superior to the coarse-resolution RCM simulations in the representing precipitation in the present-day climate, and thus offer a promising way forward for investigations of climate and climate change at local to regional scales.