Description:
Greenland ICESat mass balance maps from Zwally et al. (2011) are available as maps or in an ASCII file. The data are defined on a 50km. polarstereographic grid with standard latitude 70°N, orientation 315°E, nodes at the centers of the cells, using the Topex/Poseidon ellipsoid:
Semimajor axis:  6378136.300 m  Semiminor axis:  6356751.601 m 
Inverse Flattening:  298.2570000  Eccentricity:  0.08181922146 
The data were masked at the edge of the coterminous ice sheet as defined by the surface type mask from Ekholm (1996). The actual edge was abstracted from this grid using an IDL™ routine (find_boundary.pro) developed by David Fanning (http://www.idlcoyote.com) that uses the chaincode algorithm; the boundary was then edited to remove anomalies. This edge was used to determine the fraction of each grid cell at the margin that is on the coterminous ice sheet. The nominal area of each grid cell is 2500 square km. The actual area varies slightly with latitude due to the projection, but areas in the table that are significantly less than 2500 square km. are for cells that are only partially on the coterminous ice sheet.
The data included in the file are:
 Lat (deg N), Lon (deg E) of the centers of the 50km cells
 dH/dt and its uncertainty (cm/year)
 dC_T/dt and its uncertainty (cm/year)
 dB/dt and its uncertainty (cm/year)
 dI/dt (cm/year)
 dM/dt and its uncertainty (Gt/year/(50km)^{2})
 Area of grid cell on ice sheet (km^{2})
 Elevation at center of grid cell (m above the EGM96 geoid), based on the ICESat DEM generated by DiMarzio et al. (2007)
 A flag marking cells for which dH/dt was kriged
Downloads:
Greenland mass balance data used in Zwally et al. 2011 [download data]
Figures
Smoothed 
Grid cells 

dH/dt 
σ _{dH/dt} 
dH/dt 
σ _{dH/dt} 
dC_T/dt 
σ _{dC_T/dt} 
dC_T/dt 
σ _{dC_T/dt} 
dB/dt 
σ _{dB/dt} 
dB/dt 
σ _{dB/dt} 
dI/dt 

dI/dt 

dM/dt 
σ _{dM/dt} 
dM/dt 
σ _{dM/dt} 
Area 

Area 

Elevation 

Elevation 
Citation
Use the following reference for this page or the data accessed from this page. Please fill in the date on which the page or data were accessed.
Zwally, H. Jay, Jun LI, Anita C. Brenner, Matthew Beckley, Helen G. Cornejo, John DiMarzio, Mario B. Giovinetto, Thomas A. Neumann, John Robbins, Jack L. Saba, Donghui Yi, and Weili Wang, 2011, Greenland ice sheet mass balance data, GSFC Cryospheric Sciences Laboratory.
REFERENCES
DiMarzio, J., A. Brenner, R. Schutz, C. A. Shuman, and H. J. Zwally, 2007, GLAS/ICESat 1 km laser altimetry digital elevation model of Greenland, Boulder, Colorado USA: National Snow and Ice Data Center. Digital media.
Ekholm, Simon, 1996, “A full coverage, highresolution, topographic model of Greenland computed from a variety of digital elevation data”, Journal of Geophysical Research, 101 (B10), 2196121972, 1996 Oct 10.
Zwally, H. Jay, Jun LI, Anita C. Brenner, Matthew Beckley, Helen G. Cornejo, John DiMarzio, Mario B. Giovinetto, Thomas A. Neumann, John Robbins, Jack L. Saba, Donghui Yi, Weili Wang, 2011, "Greenland ice sheet mass balance: distribution of increased mass loss with climate warming; 200307 versus 19922002" , Journal of Glaciology, Vol. 57, No. 201, pp 88102, 2011.