SNOWPACK simulations forced by MERRA-2 for Antarctic Ice Shelves

This repository contains the SNOWPACK simulations used in the manuscript:
Banwell, A., Wever, N., Dunmire, D. and Picard, G. (2023): Quantifying Antarctic-wide ice-shelf surface melt volume using microwave and firn model data: 1980 to 2021. Geophys. Res. Lett. (accepted).

For each MERRA-2 grid point that is on an ice shelf, the zip file of the corresponding simulation is named: <latitude>_<longitude>_ICESHELVES.zip

Each zip file then contains the following files:

• output/-72.000_69.375_ICESHELVES.ini: This file contains the model settings as used for the simulation
• output/-72.000_69.375_ICESHELVES.pro: This file contains the detailed, layered SNOWPACK output, with for each layer, for example, temperature, density, liquid water content, grain size, etc. Can be visualized using niViz.
• output/-72.000_69.375_ICESHELVES.smet: This file contains the SNOWPACK time series output, like surface sublimation, snow surface temperature, latent heat flux, etc. Can be visualized using niViz.
• output/-72.000_69.375_ICESHELVES.sno: This file contains the SNOWPACK model state at the end of the simulation.
• output/-72.000_69.375_ICESHELVES.snobackup: This file contains the SNOWPACK model state from the last backup point during the simulation.
• output/-72.000_69.375_ICESHELVES.haz: This file contains very specific SNOWPACK model output and was ignored in the study associated with this dataset.
• output/-72.000_69.375_ICESHELVES.hazbackup: This file contains very specific SNOWPACK model output from the last backup point during the simulation and was ignored in the study associated with this dataset.

Also available are statistics derived from the SNOWPACK model output using the code published at doi: 10.5281/zenodo.7957639 (GitHub repository):

statistics.zip
==========

Contains statistics calculated from the SNOWPACK output. Statistics per region are stored in the folders stats622 (for yearly statistics) and stats_per_day622 (for daily statistics). Statistics per ice shelf are stored in the folders stats_iceshelves622 (for yearly statistics) and stats_iceshelves_per_day622 (for daily statistics). For each ice shelf and region, the following files are available:

• melt_RX.txt and melt_SX.txt: sum of melt amount (kg/m2) for region RX or ice shelf SX, respectively.
• meltdays_Amm_RX.txt and meltdays_Amm_SX.txt: number of days exceeding A mm of melt for region RX or ice shelf SX, respectively.
• mswater_Amm_RX.txt and mswater_Amm_SX.txt: number of days with total firn column water content exceeding A kg/m2 for region RX or ice shelf SX, respectively.
• mswaterA_B_Cmm_RX.txt and mswaterA_B_Cmm_SX.txt: number of days with more than C kg/m2 amount of liquid water in the firn between A and B meters below the surface for region RX or ice shelf SX, respectively.

Each of the files report the year, respectively the date, in the first column, followed by the statistics for each grid point in the region/ice shelf, followed by the mean and standard deviation over all grid points in the respective region/ice shelf listed in the preceding columns. The first line is a header.

To find out the sequence by which MERRA-2 points appear in the output columns, please refer to the list in the file list_points.txt. This list is constructed as follows. First there is a header indicating that what follows are regions. Then, each line contains a comma-delimited list of the region number, latitude, and longitude, respectively. The first line for a region is reported in the column with header 1 in the statistics file, the second line in the column with header 2, and so on. After all regions are listed, there is again a header line denoting that what follows are the ice shelves. Similar to the section for the regions, each following line contains a comma-delimited list of the ice shelf number, latitude, and longitude, respectively. The numbering of regions and ice shelves is listed in the tables below.

forcingstatistics.zip
===============

Contains monthly statistics of the forcing variables TA (air temperature, K), QI (specific humidity, -), ILWR (incoming longwave radiation W/m2), ISWR (incoming shortwave radiation, W/m2), PSUM (precipitation, kg/m2/h), and VW (wind speed, m/s). The statistics for each region and ice shelf are stored in monthlystats and monthlystats_iceshelves, respectively. Each file name contains the forcing variable and the region/ice shelf number. The numbering of regions and ice shelves can be found in the tables below. Each file then contains the month (expressed as YYYYMM), followed by means of the specific variable for each MERRA-2 grid point in the region/ice shelves (in the same sequence as for the statistics files discussed above), followed by the mean and standard deviation over all MERRA-2 grid points listed in the preceding columns.