Journal Article

Modelling the climate and surface mass balance of polar ice sheets using RACMO2 – Part 2: Antarctica (1979–2016)

van Ulft, Lambertus H., Krüger, Konstantin, Lenaerts, Jan T. M., Reijmer, Carleen H., van Tricht, Kristof, Ligtenberg, Stefan R. M., Wouters, Bert, Jakobs, Constantijn L., van Meijgaard, Erik, Noël, Brice P. Y., Birnbaum, Gerit, Trusel, Luke D., van de Berg, Willem Jan, Wuite, Jan, van den Broeke, Michiel R., Amory, Charles, Medley, Brooke, van Wessem, Jan Melchior, Lhermitte, Stef

2018

Overview

We evaluate modelled Antarctic ice sheet (AIS) near-surface climate, surface mass balance (SMB) and surface energy balance (SEB) from the updated polar version of the regional atmospheric climate model, RACMO2 (1979–2016). The updated model, referred to as RACMO2.3p2, incorporates upper-air relaxation, a revised topography, tuned parameters in the cloud scheme to generate more precipitation towards the AIS interior and modified snow properties reducing drifting snow sublimation and increasing surface snowmelt. Comparisons of RACMO2 model output with several independent observational data show that the existing biases in AIS temperature, radiative fluxes and SMB components are further reduced with respect to the previous model version. The model-integrated annual average SMB for the ice sheet including ice shelves (minus the Antarctic Peninsula, AP) now amounts to 2229 Gt y−1, with an interannual variability of 109 Gt y−1. The largest improvement is found in modelled surface snowmelt, which now compares well with satellite and weather station observations. For the high-resolution (∼ 5.5 km) AP simulation, results remain comparable to earlier studies. The updated model provides a new, high-resolution data set of the contemporary near-surface climate and SMB of the AIS; this model version will be used for future climate scenario projections in a forthcoming study.

• Publisher: Copernicus GmbH,Copernicus Publications
• Subject: Analysis / Annual variations / Antarctic ice sheet / Arctic research / Atmospheric models / Climate / Climate models / Clouds / Computer simulation / Drifting snow / Earth sciences & physical geography / Energy balance / Fluxes / Future climates / Glaciation / High resolution / Ice / Ice sheets / Ice shelves / Interannual variability / Land ice / Mass balance / Mass balance of ice sheets / Modelling / open climate campaign / Physical, chemical, mathematical & earth Sciences / Physique, chimie, mathématiques & sciences de la terre / Polar environments / Precipitation / Rainfall / Resolution / Satellite observation / Satellites / Sciences de la terre & géographie physique / Snow / Snowdrifts / Snowmelt / Sublimation / Surface energy / Surface energy balance / Surface properties / Topography (geology) / Weather stations