Abstract
Abstract. Increasing computational resources and the demands of impact modelers, stake holders, and society envision seasonal and climate simulations with the convection-permitting resolution. So far such a resolution is only achieved with a limited-area model whose results are impacted by zonal and meridional boundaries. Here, we present the setup of a latitude-belt domain that reduces disturbances originating from the western and eastern boundaries and therefore allows for studying the impact of model resolution and physical parameterization. The Weather Research and Forecasting (WRF) model coupled to the NOAH land–surface model was operated during July and August 2013 at two different horizontal resolutions, namely 0.03 (HIRES) and 0.12° (LOWRES). Both simulations were forced by the European Centre for Medium-Range Weather Forecasts (ECMWF) operational analysis data at the northern and southern domain boundaries, and the high-resolution Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA) data at the sea surface.The simulations are compared to the operational ECMWF analysis for the representation of large-scale features. To analyze the simulated precipitation, the operational ECMWF forecast, the CPC MORPHing (CMORPH), and the ENSEMBLES gridded observation precipitation data set (E-OBS) were used as references.Analyzing pressure, geopotential height, wind, and temperature fields as well as precipitation revealed (1) a benefit from the higher resolution concerning the reduction of monthly biases, root mean square error, and an improved Pearson skill score, and (2) deficiencies in the physical parameterizations leading to notable biases in distinct regions like the polar Atlantic for the LOWRES simulation, the North Pacific, and Inner Mongolia for both resolutions.In summary, the application of a latitude belt on a convection-permitting resolution shows promising results that are beneficial for future seasonal forecasting.
Highlights
On longer timescales, like seasonal, decadal, and climate predictions, global general circulation models (GCMs) are commonly applied with a typical horizontal resolution in the range of 1–2◦ (e.g., Taylor et al, 2012)
The Weather Research and Forecasting (WRF) model coupled to the NOAH land– surface model was operated during July and August 2013 at two different horizontal resolutions, namely 0.03 (HIRES) and 0.12◦ (LOWRES)
The reason to choose a 0.12◦ resolution is that the current resolution of the European Centre for Medium-Range Weather Forecasts (ECMWF) operational model is similar and it is similar to the resolution applied in the EURO-Coordinated Regional Downscaling Experiment (CORDEX) experiment (e.g., Jacob et al, 2014)
Summary
Like seasonal, decadal, and climate predictions, global general circulation models (GCMs) are commonly applied with a typical horizontal resolution in the range of 1–2◦ (e.g., Taylor et al, 2012). In the Coordinated Regional Downscaling Experiment (CORDEX; http://www.cordex.org; Giorgi et al, 2009), several RCMs are applied with grid distances of 0.44◦ for different continental-scale regions around the globe at affordable computing power. As this resolution still suffers from a horizontal resolution that is too coarse, e.g., the EURO-CORDEX project (http: //www.euro-cordex.net/) focuses on regional climate simulations for Europe at 0.11◦ resolution. Evaluation studies of Kotlarski et al (2014), Vautard et al (2013), and Prein et al (2015a) indicated that increasing the resolution from 0.44 to 0.11◦ results in beneficial effects with respect to the simulation of 2 m temperatures with biases in the range of ±2 K. Prein et al (2015a) show a Published by Copernicus Publications on behalf of the European Geosciences Union
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
