DOI: 10.5281/zenodo.16902106
title: Monthly RACMO2.4p1 data for Antarctica (11 km) forced with ERA5 (1979-2023), CESM2 (1985-2100) and MPI-ESM (1985-2100)

description: This data set includes the surface mass balance (SMB) components, surface energy budget (SEB) variables and near-surface climate variables as is simulated by the regional atmospheric climate model RACMO2.4p1 over Antarctica. Included are simulations forced with ERA5 (1979-2023), MPI-ESM (1985-2014 historical and 2015-2100 ssp370) and CESM2 (1985-2014 historical and 2015-2100 ssp370). RACMO is forced at the lateral boundaries with multilevel data of wind speed, temperature, humidity and pressure and at the sea-surface boundary with sea ice extent and sea surface temperature from ERA5 or the GCM. RACMO is run with 40 vertical levels and on an 11 km horizontal resolution grid. The domain includes Antarctica, the Drake passage and parts of Patagonia.

Variables are monthly-averaged (named monthlyA), monthly-accumulated (named monthlyS), or part of the mask file. Variables ending with ‘gl’ are for glaciated surfaces only. Integrating a variable over the domain (e.g., calculating the SMB in Gigaton per month) requires multiplying the variable with the grid cell area (‘Area’) and ice mask (‘IceMask’) fields, both can be found in the PXANT11_masks.nc file. The ice mask is a fractional field since RACMO2.4p1. If limiting the integration to the ice sheet only, the considered variable has to be multiplied with the ‘Icesheet_Only’ field that is also available in the mask file, in addition to multiplying it with the grid cell area and ice mask. The mask file includes more fields, which are also listed below. Unlisted variables and listed variables with a higher temporal resolution are available on request. This data set includes the following variables: 

Surface mass balance (SMB) variables (in kg m-2 mo-1 or mm water equivalent mo-1):

smbgl: (Specific) Surface mass balance

mltgl: Surface snow melt production

rfrzgl: Refreezing of liquid water

sf: Solid precipitation

pr: Total precipitation (to determine rain: ra = pr – sf)

totrunoff: (Near-)surface meltwater runoff on glaciated surfaces

subltot: Sublimation of snow (including sublimation of suspended snow in the atmosphere caused by blowing snow). Negative values are sublimation, positive values are riming.

sndivgl: Erosion of blowing snow

 

Surface Energy Budget (SEB) variables (in J m-2): 

To convert to W m-2, divide by the number of seconds in a month.

rsds: Downwelling shortwave radiation at the surface

rsusgl: Upwelling shortwave radiation at the surface

rlds: Downwelling longwave radiation at the surface

rlusgl: Upwelling longwave radiation at the surface

hfssgl: Sensible heat flux, defined positive towards the surface

hflsgl: Latent heat flux, defined positive toward the surface

gbot: Ground heat flux for glaciated surfaces

 

Other variables:

tas: Near-surface air temperature (2 m above the surface)

huss: Near-surface specific humidity (2 m above the surface)

ps: Surface pressure

sfcwind: Near-surface wind speed

 

Fields available in the mask file (PXANT11_masks.nc):

lat: Latitude

lon: Longitude

lat_bnds: Latitude of the four corners of each grid point

lon_bnds: Longitude of the four corners of each grid point

IceMask: Ice mask fraction (grounded ice and ice shelves)

LSM: Land-sea mask (0 or 1)

Geopotential: Geopotential height

Topography: Topographic height of the surface

Area: Surface area of each grid point

Basins: Drainage basins following the IMBIE convention

LakeMask: Lake mask fraction

Icesheet_Only: Mask showing which grid points are considered to be part of the Antarctic ice sheet (0 or 1)IceShelf: Ice shelve ID with naming given in iceshelf_mapping.csv