Description
Aerosols affect climate through scattering and absorbing radiation. Their high variability challenges their representation within climate models, which would benefit from the use of high resolution. Regional Climate Models (RCMs) can provide such small-scale information, however most of them use simplified schemes to treat aerosol radiative effects. The main goal of this project is to assess the influence of the aerosol-radiation interactions within a Regional Climate Model (RCM), contributing to reduce the model-derived uncertainty in climate modeling and to explore their effect over a topographically complex and vulnerable region: the Mediterranean area. The radiative effect due to aerosol-radiation interaction over the Mediterranean, a highly complex and vulnerable region to climate change, will be assessed using the NMMB/BSC-CTM as a RCM. The system sensitivity to the aerosols’ definition will be explored, taking advantage of the expertise in aerosols’ effects on climate of the Norwegian Meteorological Institute, donor partner, and the experience in regional climate modelling of the project promoter, Polytechnic University of Catalonia. The results of the project will benefit the science community.
Summary of project results
The aerosols influence on climate is one of the hot spots of climate research, as they continue to contribute the largest uncertainty to estimates and interpretations of the Earth’s changing energy budget. This project aims to analyse the impact of the aerosol definition on regional climate projections over North-Africa, Middle East and Europe, considering aerosol-radiation interactions, at high resolution, extending the range of applicability of the Non-Hydrostatic Multiscale Meteorological Model on the B Grid – BSC Chemical Transport Model (NMMB/BSC-CTM) from near-t4erm to long-term simulations. Three specific objectives were pursued and attempted: 1) Inter-comparison of the different aerosol climatologies commonly used within RCMs, regarding their spatio-temporal variability and optical properties. 2) Analysis of the direct effect of aerosols on RCM projections and identification of the key characteristics that influence model results. 3) Assessment of the mineral dust-climate feedbacks over the North African, Middle East and Euro-Mediterranean area, by the application of an online coupled RCM. The project activities were presented in several internal seminars at the Norwegian Meteorological Institute and at the Technical University of Cataluña, and a scientific article is in preparation, to be submitted to an international peer-reviewed journal. Primary beneficiaries of the project results are the aerosols’ and regional climate modelling scientific communities. This project provides an additional evaluation on the currently used schemes for aerosol characterization within regional climate and numerical weather prediction models, as well as a quantification of their effects upon regional climate projects. More importantly, it provides insight on the key parameters (temporal variability, optical properties, etc.) that influence model results, and therefore a diagnosis of those aspects that should be reviewed or accounted for. In this sense, it also contributes to the assessment of uncertainties on regional climate modelling, improving our understanding of the aerosol-radiation interactions and its influence in areas particularly vulnerable to climate change, it tests the ability of new integrated modelling systems to be used for long-term regional model simulations.
Summary of bilateral results
The partnership among the Engineering projects Department of the Technical University of Catalonia (UPC) and the Earth Sciences Department of the Barcelona Supercomputing Center (ES-BSC-CNS) on the one side, and the Climate Modeling and Air Polution Division of the Norwegian Meteorological Institute (MetNO) on the other side, made possible the development of the project. The ES-BSC-CNS provided the necessary means for the simulations performed, including the software and computational resources. All simulations were run at the MareNostrum Supercomputing. Expertise on regional climate modelling and analysis of high resolution climate data constituted the main contribution of the granted researcher to the project. The Climate Modelling and Air Pollution Division of the MetNO, and specifically the partner researcher, constitutes an international reference on aerosols’ and climate research. He contributed to the project development from the fist stages, giving advice on the project goals definition and the scenarios design. His expertise on aerosol modelling and effects upon climate also constituted a fundamental asset on the interpretation of results and conclusions. The project contributed to establish stronger relations and to plan further joint activities. The collaboration between both partner institutions will continue in the framework of the project and beyond. The Earth Sciences Department of the BSC-CNS (Barcelona SuperComputing Centre) will contribute to the AEROCOM phase-II project (
http://aerocom.met.no), leaded by Dr. M. Shulz, the hosting researcher at MetNo. The NMMB7BSC-CTM model will be applied at the global scale and included in the AEROCOM ensemble. One-year long runs to assess the aerosol optical properties and 10-year long runs to investigate aerosol trends will be performed. In order to guarantee the sustainability of the joint cooperation, partners foresee to submit applications to different funding schemes. An application was submitted to the Spanish Supercomputation Network, and a project proposal on the elaboration of a mineral dust reanalysis using the NMMB/BSC-CTM, suitable for high resolution meteorological and climatological applications, will be prepared to the RETOS call of the Spanish State plan of Scientific and Technical Research.