GENERAL INFORMATION

1. Title of Dataset: Data from: Accelerating ice loss from peripheral glaciers in North Greenland.

2. Author Information
Shfaqat A. Khan*1, William Colgan2, Thomas A. Neumann3, Michiel R. van den Broeke4, Kelly M Brunt3, Brice Noël4, Jonathan L. Bamber5,6, Javed Hassan1, and Anders A Bjørk7

1.	DTU Space, Technical University of Denmark, Denmark
2.	Department of Glaciology and Climate, Geological Survey of Denmark and Greenland, Denmark.
3.	NASA Goddard Space Flight Center, Greenbelt, MD, USA
4.	Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, The Netherlands.
5.	Bristol Glaciology Centre, University of Bristol, UK.
6.	Department of Aerospace and Geodesy, Data Science in Earth Observation, Technical University of Munich, Germany
7.	Department of Geosciences and Natural Resources, University of Copenhagen, Denmark


* corresponding author e-mail: abbas@space.dtu.dk


3. Date of data collection: 2003-2021

4. Geographic location of data collection: Greenland.

5. Funding sources that supported the collection of the data: Danmarks Frie Forskningsfond, Award: 1026-00085B, and H2020 European Research Council, Award: 694188 (GlobalMass)

6. Recommended citation for this dataset: Khan, Shfaqat Abbas et al. (2022), Data from: Accelerating ice loss from peripheral glaciers in North Greenland, Dryad, Dataset, https://doi.org/10.5061/dryad.zpc866tb8

DATA & FILE OVERVIEW

1. Description of dataset

(1) Mean elevation change rates of the Greenland peripheral glaciers during, Feb 2003 - Oct 2009, Oct 2008 - Apr 2019, and Oct 2018 – Dec 2021 obtained from
 from ICESat and ICESat-2 data. The grid resolution is 500x500 meters.

(2) Mean elastic uplift rates of the bedrock (in mm/yr) due to ice loss during, Feb 2003 - Oct 2009, Oct 2008 - Apr 2019, and Oct 2018 – Dec 2021.

(3) Mean firn compaction rates in m/yr during, Feb 2003 - Oct 2009, Oct 2008 - Apr 2019, and Oct 2018 – Dec 2021.

(4) Glacial Isostatic Adjustment- GIA rates in mm/yr from the GNET-GIA empirical model of Khan et al. (2016).

(5) Time series of mean surface air temperature in degrees Celcius during May-September in north, northwest, southeast, southwest, and northwest Greenland from RACMO2.3p2.
time span=during 1959-2021

2. File List: 
	File 1 GRL_Khan_2022GL098915.zip

This compressed file contains five directories:

	Directory 1 "dhdt": Description: Mean elevation change rates of the Greenland peripheral glaciers during, Feb 2003 - Oct 2009, Oct 2008 - Apr 2019, and Oct 2018 – Dec 2021
      Directory 2 "elastic" Description: Mean elastic uplift rates of the bedrock (in mm/yr) due to ice loss during, Feb 2003 - Oct 2009, Oct 2008 - Apr 2019, and Oct 2018 – Dec 2021.
      Directory 3 "firn" Description: Mean firn compaction rates in m/yr during, Feb 2003 - Oct 2009, Oct 2008 - Apr 2019, and Oct 2018 – Dec 2021.
      Directory 4 "GIA" Description: Glacial Isostatic Adjustment- GIA rates in mm/yr from the GNET-GIA empirical model of Khan et al. (2016).
      Directory 5 "temp" Description: Time series of mean surface air temperature in degrees Celcius during May-September in north, northwest, southeast, southwest, and northwest Greenland from RACMO2.3p2.

	
METHODOLOGICAL INFORMATION

We use ICESat data from February 2003 to October 2009 to estimate elevation changes over the ice surface. We estimate height changes over the ice surface, on a regular grid with a resolution of 500x500 m that covers all of Greenland’s peripheral glaciers. We use all available ICESat data to create height time series at each grid point. At each grid point, we fit a trend, a second-order surface topography, and a seasonal term to account for the annual surface changes.
The observed height change rates from ICESat are interpolated into a regular grid of 500x500 m. The interpolation is performed using the ordinary kriging method. We used the observed elevation change rates to estimate an empirical semi-variogram. Next, we fit an exponential model variogram (with a range of 60 km) to the empirical semi-variogram to take the spatial correlation of elevation change rates into account in the error budget. For each grid point, we estimate elevation change rate dh and associated error. 
We correct the observed height change rates for firn compaction, elastic uplift rates from present-day mass changes, and long-term past ice changes (Glacial Isostatic Adjustment- GIA). We correct for GIA, using the GNET-GIA empirical model of Khan et al. (2016). For each grid point, we estimate the GIA uplift rate and the associated uncertainty. To correct for elastic uplift of the bedrock, we convolve ice loss estimates of peripheral glaciers and the Greenland ice sheet with the Green’s functions derived by Wang et al. (2012) for elastic Earth model iasp91 with refined crustal structure from Crust 2.0.


Khan, S. A. et al. (2016). Geodetic measurements reveal similarities between post-Last Glacial Maximum and present-day mass loss from the Greenland ice sheet. Sci. Adv. 2, e1600931, https://doi.org/10.1126/sciadv.1600931

Wang, H. et al. (2012). Load Love numbers and Green’s functions for elastic Earth models PREM, iasp91, ak135, and modified models with refined crustal structure from Crust 2.0, Computers and Geosciences. 49: 190-199. https://doi.org/10.1016/j.cageo.2012.06.022.

