Interactive comment on “ Evaluation of a Unique Approach to High-Resolution Climate Modelling using the Model for Prediction Across Scales ( MPAS ) version 5 . 1 ”

Abstract

We present multi-seasonal simulations representative of present-day and future thermodynamic environments using the global Model for Prediction Across Scales-Atmosphere (MPAS) version 5.1 with high resolution (15 km) throughout the Northern Hemisphere. We select ten simulation years with varying phases of El Niño-Southern Oscillation 10 (ENSO) and integrate each for 14.5 months. We use analysed sea surface temperature (SST) patterns for present-day simulations. For the future climate simulations, we alter present-day SSTs by applying monthly-averaged temperature changes derived from a 20-member ensemble of Coupled Model Intercomparison Project Phase 5 (CMIP5) general circulation models (GCMs) following the Representative Concentration Pathway (RCP) 8.5 emissions scenario. Daily sea ice fields, obtained from the monthly-averaged CMIP5 ensemble mean sea ice, are used for present-day and future simulations. 15 The present-day simulations provide a reasonable reproduction of large-scale atmospheric features in the Northern Hemisphere such as the wintertime midlatitude storm tracks, upper-tropospheric jets, and maritime sea-level pressure features as well as annual precipitation patterns across the tropics. The simulations also adequately represent tropical cyclone (TC) characteristics such as strength, spatial distribution, and seasonal cycles for most of Northern Hemispheric basins. These results demonstrate the applicability of these model simulations for future studies examining climate change effects on 20 various Northern Hemispheric phenomena, and, more generally, the utility of MPAS for studying climate change at spatial scales generally unachievable in GCMs. Plain Language Summary. We expect that high-impact weather events will change in a warmer climate. Computational constraints limit global climate models to resolutions that are too coarse to fully capture many societally significant weather 25 events, such as tropical cyclones and flooding rains in middle-latitude low-pressure systems. While these global models often provide reliable projections of changes in mean temperatures and global circulation patterns, they cannot tell us how intense, high-impact events may be altered in response to climate change. Here, we present a novel set of atmospheric simulations designed to address changes in high-impact weather events. The model covers the globe, but has higher resolution in the Northern Hemisphere. We simulate ten years sampling a range of tropical climate conditions, as represented 30 by observed ocean surface temperatures, and we carry out simulations for current and projected late 21st-century climate Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2019-34 Manuscript under review for journal Geosci. Model Dev. Discussion started: 3 April 2019 c © Author(s) 2019. CC BY 4.0 License.