The first multi-model ensemble of regional climate simulations at kilometer-scale resolution, part I: evaluation of precipitation

Nikolina Ban (1) , Cécile Caillaud (2) , Erika Coppola (3) , Emanuela Pichelli (3) , Stefan Sobolowski (4) , Marianna Adinolfi (5) , Bodo Ahrens (6) , Antoinette Alias (2) , Ivonne Anders (7) , Sophie Bastin (8) , Danijel Belušić (9) , Ségolène Berthou (10) , Erwan Brisson (2) , Rita M. Cardoso (11) , Steven C. Chan (12) , Ole Bøssing Christensen (13) , Jesús Fernández (14) , Lluís Fita (15) , Thomas Frisius (16) , Goran Gašparac (17) , Filippo Giorgi (3) , Klaus Goergen (18, 19) , Jan Erik Haugen (20) , Øivind Hodnebrog (21) , Stergios Kartsios (22) , Eleni Katragkou (22) , Elizabeth J. Kendon (10) , Klaus Keuler (23) , Alvaro Lavin-Gullon (24) , Geert Lenderink (25) , David Leutwyler (26) , Torge Lorenz (4) , Douglas Maraun (27) , Paola Mercogliano (5) , Josipa Milovac (24) , Hans-Juergen Panitz (28) , Mario Raffa (5) , Armelle Reca Remedio (16) , Christoph Schär (29) , Pedro M. M. Soares (11) , Lidija Srnec (30) , Birthe Marie Steensen (21) , Paolo Stocchi (31) , Merja H. Tölle (32) , Heimo Truhetz (27) , Jesus Vergara-Temprado (29) , Hylke de Vries (25) , Kirsten Warrach-Sagi (33) , Volker Wulfmeyer (33) , Mar Janne Zander (34)

1 ACINN - Department of Atmospheric and Cryosphere Sciences [Innsbruck]
2 CNRM - Centre national de recherches météorologiques
3 ICTP - Abdus Salam International Centre for Theoretical Physics [Trieste]
4 BCCR - Bjerknes Centre for Climate Research
5 REMHI - REgional Model and geo-Hydrological Impacts
6 IAU - Institute for Atmospheric and Environmental Sciences [Frankfurt/Main]
7 DKRZ - Deutsches Klimarechenzentrum [Hamburg]
8 SPACE - LATMOS
9 SMHI - Swedish Meteorological and Hydrological Institute
10 MOHC - Met Office Hadley Centre for Climate Change
11 Instituto Dom Luiz
12 Newcastle University [Newcastle]
13 DMI - Danish Meteorological Institute
14 Santander Meteorology Group
15 CIMA - Centro de Investigaciones del Mar y la Atmósfera
16 GERICS - Climate Service Center [Hambourg]
17 Croatia Control Ltd.
18 IBG - Institute of Bio- and Geosciences [Jülich]
19 HPSC TerrSys - Centre for High-Performance Scientific Computing in Terrestrial Systems
20 MET - Norwegian Meteorological Institute [Oslo]
21 CICERO - Center for International Climate and Environmental Research [Oslo]
22 Department of Meteorology and Climatology [Thessaloniki]
23 BTU - Brandenburg University of Technology [Cottbus – Senftenberg]
24 IFCA - Instituto de Física de Cantabria
25 KNMI - Royal Netherlands Meteorological Institute
26 MPI-M - Max-Planck-Institut für Meteorologie
27 WEGC - Wegener Center for Climate and Global Change
28 IMK - Institute for Meteorology and Climate Research
29 IAC - Institute for Atmospheric and Climate Science [Zürich]
30 DHMZ - Croatian Meteorological and Hydrological Service
31 ISAC - CNR Institute of Atmospheric Sciences and Climate
32 CESR - Center for Environmental Systems Research [Kassel]
33 IPM - Institute of Physics and Meteorology [Stuttgart]
34 Department of Environmental Sciences [Wageningen]

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 ∼ 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 (∼ 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 ∼ −40% at 12 km to ∼ −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.

Keywords: Regional climate models; Multi-model ensemble simulations; Kilometer-scale resolution; Precipitation

Domains: Climatology

Nikolina Ban, Cécile Caillaud, Erika Coppola, Emanuela Pichelli, Stefan Sobolowski, et al.. The first multi-model ensemble of regional climate simulations at kilometer-scale resolution, part I: evaluation of precipitation. Climate Dynamics, 2021, 57, pp.275-302. ⟨10.1007/s00382-021-05708-w⟩. ⟨insu-03195477v2⟩