CORDEX-WRF v1.3: development of a module for the Weather Research and Forecasting (WRF) model to support the CORDEX community

Lluís Fita (1) , Jan Polcher (2) , Theodore M. Giannaros (3) , Torge Lorenz (4) , Josipa Milovac (5) , Giannis Sofiadis (6) , Eleni Katragkou (6) , Sophie Bastin (7)

1 CIMA - Centro de Investigaciones del Mar y la Atmósfera
2 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
3 IERSD - Institute for Environmental Research and Sustainable Development
4 BCCR - Bjerknes Centre for Climate Research
5 IPM - Institut für Physik und Meteorologie [Stuttgart]
6 Department of Meteorology and Climatology [Thessaloniki]
7 SPACE - LATMOS

The Coordinated Regional Climate Downscaling Experiment (CORDEX) is a scientific effort of the World Climate Research Program (WRCP) for the coordination of regional climate initiatives. In order to accept an experiment, CORDEX provides experiment guidelines, specifications of regional domains, and data access and archiving. CORDEX experiments are important to study climate at the regional scale, and at the same time, they also have a very prominent role in providing regional climate data of high quality. Data requirements are intended to cover all the possible needs of stakeholders and scientists working on climate change miti-gation and adaptation policies in various scientific communities. The required data and diagnostics are grouped into different levels of frequency and priority, and some of them even have to be provided as statistics (minimum, maximum, mean) over different time periods. Most commonly, scientists need to post-process the raw output of regional climate models, since the latter was not originally designed to meet the specific CORDEX data requirements. This post-processing procedure includes the computation of diagnos-tics, statistics, and final homogenization of the data, which is often computationally costly and time-consuming. Therefore , the development of specialized software and/or code is required. The current paper presents the development of a specialized module (version 1.3) for the Weather Research and Forecasting (WRF) model capable of outputting the required CORDEX variables. Additional diagnostic variables not required by CORDEX, but of potential interest to the regional climate modeling community, are also included in the module. "Generic" definitions of variables are adopted in order to overcome the model and/or physics parameterization dependence of certain diagnostics and variables, thus facilitating a robust comparison among simulations. The module is computationally optimized, and the output is divided into different priority levels following CORDEX specifications (Core, Tier 1, and additional) by selecting precompilation flags. This implementation of the module does not add a significant extra cost when running the model; for example, the addition of the Core variables slows the model time step by less than a 5 %. The use of the module reduces the requirements of disk storage by about a 50 %. The module performs Published by Copernicus Publications on behalf of the European Geosciences Union. 1030 L. Fita et al.: WRF module for CORDEX output neither additional statistics over different periods of time nor homogenization of the output data.

Domaines: Physique Atmosphérique et Océanique [physics.ao-ph]; Climatologie

Lluís Fita, Jan Polcher, Theodore M. Giannaros, Torge Lorenz, Josipa Milovac, et al.. CORDEX-WRF v1.3: development of a module for the Weather Research and Forecasting (WRF) model to support the CORDEX community. Geoscientific Model Development, 2019, 12 (3), pp.1029-1066. ⟨10.5194/gmd-12-1029-2019⟩. ⟨insu-02101108⟩