This dataset contains the forcing provided to all models for the firn meltwater Retention Intercomparison Project (RetMIP).
The forcing files consist of 1) three-hourly time series of snow surface temperature, net accumulation (positive for snowfall and vapor deposition and negative for sublimation) and melt and 2) initial profiles for firn density, temperature and liquid water content. These fields are available at four sites located in different climate zones of the Greenland ice sheet: Summit, Dye-2, KAN_U and the firn aquifer site (FA). At the Dye-2 sites, two forcing data files are available: one covering 1998-2015 and another one derived from more recent instruments over the 2016 melt season.
At Summit and Dye-2 (for 1998-2015), we use data from the
GC-Net automatic weather stations (AWS), at Dye-2 for 2016 we use the AWS from
Samimi et al. (2020), at KAN_U data from the
PROMICE AWS, and at FA data from the AWS maintained by
IMAU at Utrecht University.
Surface temperature and vapour fluxes were calculated at hourly resolution using the surface energy budget closure from
van As (2005), as implemented in
Vandecrux et al. (2018). The energy budget used measurements of air temperature, humidity, pressure and net shortwave radiation. Downward longwave radiations was measured at Dye-2 (for 2016), KAN_U and FA but were extracted from the closest cell in HIRHAM regional climate model at Dye-2 (1998-2015) and Summit. Sensible and latent heat fluxes were calculated using the bulk approach and upward longwave radiation was solved iteratively at each time step.
Snowfall was derived from surface height observations available at each station, first with an a-priori surface snow density of 315 kg m-3 (
Fausto et al., 2016), then adjusted to multiple snowpit observations available at each site.
Gap-free meteorological fields were obtained using the approach from
Vandecrux et al. (2018) which adjusts the output from HIRHAM climate model to match at best the observations and use these adjusted values to fill the gaps in the instrumental records.
More information about the RetMIP protocol and on the recommended boundary conditions can be found in Vandecrux et al. (2020) and on the
RetMIP webpage.
The model outputs for the RetMIP are available here:
Vandecrux, Baptiste; Peter L. Langen; Peter Kuipers Munneke; Sebastian Simonsen; Vincent Verjans; C. Max Stevens; Sergey Marchenko; Ward van Pelt; Colin Meyer, 2020, "The firn meltwater retention model intercomparison project (RetMIP): model outputs", https://doi.org/10.22008/FK2/CVPUJL, GEUS Dataverse
