Reliability of Antarctic air temperature changes from Polar WRF: A comparison with observations and MAR outputs

Abstract

This study investigates the near-surface air temperature changes over the Antarctic Ice Sheet (AIS) since 1979 using the Polar Weather Research and Forecasting model (Polar WRF, version 3.9.1) at a horizontal resolution of 27 km. Its performance is estimated by quality-controlled monthly temperature measurements from 46 automatic and manual weather stations, and the outputs of the Regional Atmosphere Model (Modèle Atmosphérique Régional, MAR) forced by ERA-Interim (MAR-ERAI) and ERA-5 (MAR-ERA5). Although warm mean biases at interior stations and cold mean biases at coastal stations are observed for the annual and seasonal mean temperatures, all simulations exhibit robust consistency with the year-to-year variability in the observed temperatures. Compared to MAR, Polar WRF presents a warmer temperature, especially on the West AIS (WAIS). Moreover, while Polar WRF shows a poorer performance than MAR over the AP (Antarctic Peninsula) with respect to the observations, Polar WRF can generally capture the trends on the East AIS (EAIS) and WAIS and shows smaller mean biases in winter and autumn. For 1979–2018, Polar WRF shows a warming trend east of 60°E in the EAIS and parts of the AP and WAIS and an insignificant cooling trend in other regions for the annual temperature. The MAR simulations agree on the warming trend in most regions of the EAIS and WAIS but show different annual warming trends over the AP and East Antarctic Plateau.