Evaluation of a unique approach to high-resolution climate modeling using the Model for Prediction Across Scales – Atmosphere (MPAS-A) version 5.1

Abstract

We present multi-seasonal simulations representative of present-day and future environments using the global Model for Prediction Across Scales -Atmosphere (MPAS-A) version 5.1 with high resolution (15 km) throughout the Northern Hemisphere. We select 10 simulation years with varying phases of El Niño-Southern Oscillation (ENSO) and integrate each for 14.5 months. We use analyzed 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. The present-day simulations provide a reasonable reproduction of large-scale atmospheric features in the Northern Hemisphere such as the wintertime midlatitude storm tracks, uppertropospheric 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 Northern Hemisphere basins. These results demonstrate the applicability of these model simulations for future studies examining climate change effects on various Northern Hemisphere phenomena, and, more generally, the utility of MPAS-A for studying climate change at spatial scales generally unachievable in GCMs.

Climatological Changes in the Extratropical Transition of Tropical Cyclones in High-Resolution Global Simulations

“…We analyze a set of time-slice simulations conducted using the atmospheric component of MPAS, version 5.1 (Skamarock et al 2012); a complete technical description of these simulations is presented in Michaelis et al (2019). Our global model domain employs a variableresolution mesh with 15-km horizontal grid spacing throughout the entire Northern Hemisphere, expanding to 60 km in the Southern Hemisphere (Fig.…”

“…Additionally, we incorporate daily sea ice derived from this GCM ensemble under future climate conditions and set carbon dioxide (CO 2 ) concentrations in the future climate simulations to 936 ppm, consistent with the RCP8.5 emissions scenario projections for the year 2100 (Meinshausen et al 2011). With this configuration and experimental design, MPAS-A is able to produce and maintain temperature change patterns that are remarkably similar to those produced by IPCC-class GCMs (Michaelis et al 2019).…”

“…As a complement to pseudo-global warming (PGW) case studies such as Lackmann (2015) and Jung and Lackmann (2019), here we analyze a set of novel highresolution (15-km grid) multiseasonal simulations conducted in present and projected future environments using the Model for Prediction Across Scales-Atmosphere [MPAS-A; see Michaelis et al (2019) for a complete technical description of the simulation design]. In addition to high resolution, these simulations include a unique approach to lower boundary forcing that retains detailed, realistic SST features for both present-day and future simulations.…”

Development and evaluation of CO<sub>2</sub> transport in MPAS-A v6.3

“…Accurate meteorological fields are critical for an accurate CO 2 transport simulation. Michaelis et al (2019) has assessed MPAS simulated meteorology accuracy using extensive observation data. Before evaluating the simulated CO 2 , we first evaluate the MPAS simulated horizontal wind fields considering their importance in CO 2 advection.…”

Performance of MPAS-A and WRF in predicting and simulating western North Pacific tropical cyclone tracks and intensities

“…Huang et al 2017Huang et al , 2019 and for "climatological" studies (e.g. Davis et al 2016;Michaelis et al 2019). However, the major shortcoming for the standard variableresolution meshes lies in the lack of flexibility for customizing meshes based on users' specific needs (e.g.…”