A Mesoscale Regional Reanalysis for Ireland

Abstract

Introduction: Climate reanalyses are an important source of information for monitoring climate as well as for the validation and calibration of numerical weather prediction models. MÉRA (Met Éireann ReAnalysis) is a 35-year reanalysis project being undertaken by Met Éireann staff. The HARMONIE-AROME canonical configuration of the HIRLAM-ALADIN system is being used to produce a high resolution gridded dataset of atmospheric, near surface and surface parameters for the period 1981 to 2015. The data assimilation component of HARMONIE-AROME is described in Brousseau et al. (2011) and the forecast component is described in Seity et al. (2011) with updates included in Bengtsson et al. (2016). HARMONIE-AROME uses the SURFEX externalised surface scheme (Masson et al., 2013) for surface data assimilation and the modelling of surface processes. The harmonie-38h1.2 tagged version of HARMONIE-AROME is being used to carry out the atmospheric simulations. The MÉRA dataset will extend the knowledge gained from observations as the model grid is much finer than observational coverage over Ireland and will include many parameters that are not routinely observed. It will be completed in spring 2017 with data being made available soon after. This article provides an overview of the HARMONIE-AROME implementation used for the MÉRA project as well as a preliminary analysis of the final ten years of data.