Mass-balance model inputs for the Kaskawulsh River headwaters

This dataset contains the input files necessary to run the mass-balance model (see Young et al. (2021), Robinson et al. (2024)) for the Kaskawulsh River headwaters from 1980–2022. Downscaled/bias corrected temperature/precipitation inputs will be uploaded separately due to the large file sizes.

Downscaling > CoarseNARR_KRH

This folder contains the coarse North American Regional Reanalysis (NARR) data that were downscaled to obtain the temperature/precipitation inputs used to drive the Kaskawulsh River headwaters mass-balance model (see Robinson, 2024). 

All files contain an array of 6 x 6 gridcells, centered on the Kaskawulsh Glacier, Yukon, Canada. The bottom left corner of the grid has coordinates 502592 E, 6624579 N and is located over Yakutat Bay, Alaska. 

Variables: 

• air: NARR 3-hourly multi-level air temperatures

• hgt: NARR 3-hourly multi-level geopotential height

• apcp: NARR daily total surface precipitation

• KRH_CE.nc: Time-invariant elevation of NARR gricells

Input_geometry > KRH

This folder contains the input geometries needed to run the model for the Kaskawulsh River headwaters.

KRH_Xgrid.txt / KRH_Ygrid.txt - contains the Easting/Northing (UTM 7N) of each gridcell in the model domain. 

Zgrids - a folder containing the annual surface elevation grids (m a.s.l.) for 1979–2022 (see Robinson et al. (2024) for details on how these were derived.

KRH_SfcType.txt - a value of 0 indicates the gridcell is glacierized terrain, a value of 1 indicates that the gridcell is non-glacierized terrain. 

KRH_Tributaries.txt - gridcell value indicates which portion of the Kaskawulsh Glacier the gridcell belongs to (1 = South Arm, 2 = Stairway Glacier, 3 = Central Arm, 4 = North Arm, 5 = Trunk). 

Solar

Contains one file per year with the 3-hourly potential direct clear-sky solar radiation, calculated using the shading program from the Hock (1999) Distributed Enhanced Temperature-Index Model (DETIM). For details see Hock (1999).

Debris

‘KRH_debrismap.txt’ is a text file with dimensions  x,y = 230 gridcells x 329 grid cells. Gridcells are 200 m x 200 m. Each gridcell contains either a value representing the estimated debris thickness (in meters), or NaN if the gridcell is not debris covered. Debris thicknesses are from the Rounce et al. (2021) global debris thickness dataset, interpolated to the Kaskawulsh River headwaters 200 m domain by Robinson (2024).

For details on the debris thickness estimate, see Rounce et al. (2021). For details on the interpolation of the original debris thickness estimate to the gridcell size of the model, see Robinson (2024).

Tuning > parameters

This directory contains a folder ‘initial_params’ with all the original values of a_ice, a_snow, and MF used to tune all the mass-balance models in Robinson et al. (2024) (in groups of 10,000 param combinations). 

Each additional directory contains the final 100 parameter combinations tuned for each model presented in Robinson et al. (2024), including:

1. The reference model.

2. The debris-free model.

3. The model with sub-debris melt-scaling from Rounce et al. (2021).

4. The model with uncorrected accumulation.

5. The model with accumulation bias corrected with precipitation gauge data.

Tuning > snowlines

Contains 53 .npy files with the rasterized versions of observed snow cover on the Kaskawulsh Glacier delineated from satellite images (see Robinson, 2024). These rasters are used in the second stage of tuning  to compare modelled and observed snowlines.