Data set: "Poleward shift of subtropical highs drives Patagonian glacier mass loss"

This data set includes the materials required to reproduce the figures and tables presented in the study: "Poleward shift of subtropical highs drives Patagonian glacier mass loss". The data consist of:

ASCII files:

SMB-components.MAR3v14.1940-2023.PAT.txt: time series of spatially integrated Patagonian glacier annual surface mass balance (SMB) components in Gt per year from ERA5-forced MAR3v14 at 5 km, statistically downscaled to 500 m resolution (1940-2023). SMB components include SMB, total precipitation (PR), snowfall (SF), rainfall (RA), runoff (RU), total melt (ME), refreezing and retention (RF), total sublimation (SU). Note that MAR3v14 does not account for drifting snow erosion (ER).

SMB-components.RACMO2.3p2.1979-2023.PAT.txt: time series of spatially integrated Patagonian glacier annual SMB components in Gt per year from ERA5-forced RACMO2.3p2 at 5.5 km, statistically downscaled to 500 m resolution including precipitation adjustment (1979-2023). SMB components include SMB, total precipitation (PR), snowfall (SF), rainfall (RA), runoff (RU), total melt (ME), refreezing and retention (RF), total sublimation (SU), and drifting snow erosion (ER). 

Netcdf files:

XXXX.1940-2023.MAR3v14.PAT.0.5km.YY.nc: map of annual SMB component XXXX expressed in kg per m² or mm w.e. per year from ERA5-forced MAR3v14 at 5 km, statistically downscaled to 500 m resolution covering Patagonian glaciers and icefields (1940-2023).

XXXX.1979-2023.RACMO2.3p2.PAT.0.5km.YY.nc: map of annual SMB component XXXX expressed in kg per m² or mm w.e. per year from ERA5-forced RACMO2.3p2 at 5.5 km, statistically downscaled to 500 m resolution with precipitation adjustment covering Patagonian glaciers and icefields (1979-2023).

SMB components XXXX include: SMB (smb_rec), total precipitation (precip), snowfall, rainfall (precip - snowfall), runoff, total melt (snowmelt), refreezing and retention (refreeze), total sublimation (subl), and drifting snow erosion (sndiv). Note that MAR3v14 does not account for drifting snow erosion. Annual mean glacier near-surface temperature (t2m) is also available from statistically downscaled MAR3v14 and RACMO2.3p2 at 500 m (ºC).

      3. PAT_icemask_lon_lat_0.5km.nc: fractional ice mask ranging from 0 (ice-free) to 1 (fully ice-covered), and longitude/latitude of the 500 m grid.

The projection used for statistical downscaling is Polar Stereographic South (EPSG:3031) with a spatial resolution of 500 m x 500 m. 

Additional data: The gridded, daily downscaled SMB data sets from the ERA5-forced MAR3v14 (1940-2023) and RACMO2.3p2 reconstructions (1979-2023) are freely available from the authors upon request and without conditions (contact: [e-mail]).

Abstract: Patagonian glaciers have been rapidly losing mass in the last two decades, but the driving processes remain poorly known. Here we use two state-of-the-art regional climate models to reconstruct long-term (1940-2023) glacier surface mass balance (SMB), i.e., the difference between precipitation accumulation, surface runoff and sublimation, at about 5 km spatial resolution, further statistically downscaled to 500 m. High-resolution SMB agrees well with in-situ observations and, combined with solid ice discharge estimates, captures recent GRACE/GRACE-FO satellite mass change. Glacier mass loss coincides with a long-term SMB decline (-0.35 Gt yr−2), primarily driven by enhanced surface runoff (+0.47 Gt yr−2) and steady precipitation. We link these trends to a poleward shift of the subtropical highs favouring warm northwesterly air advections towards Patagonia (+0.14ºC dec−1 at 850 hPa). Since the 1940s, Patagonian glaciers have lost 1,350 ± 449 Gt of ice, equivalent to 3.7 ± 1.2 mm of global mean sea-level rise.