Greenland - Release Level 05 (RL-05)
(Go to RL-04)

Below are updated results continued from our recent
paper Harig and
Simons [2012]. As of the last update January 2013, these results
use the Release level 5 UTCSR
(http://www.csr.utexas.edu/grace/)
data solutions from January 2003 up to and including January 2013.
The past few years have seen unprecedented melting in Greenland measured by a variety of indicators (see the 2011 Arctic Report Card: Greenland for a good scientific summary). For GRACE mass measurements this means that recent years have increased the trend estimated since 2003. The RL-05 data do not include months from 2002 that appear in the RL-04 data. As a result, Greenland estimates will be somewhat larger than estimates using RL-04 data since the months from 2002 were all below the average melting trend.

The latest trend estimate increased from our paper to -241 Gigatons per year by (1) using more months from September 2011 to January 2013 and (2) the absence of 2002 data. The trend estimate is an average for the middle of the time period. So the slope of the time around 2007 is about -241 Gt/yr. 2003 was actually melting less than this, while 2012 was melting much more than this. The estimate just for 2012 is that Greenland lost 412 Gt of ice mass (see Fig 3).

Figure 1: Total mass change trend for Greenland. The solid black
line is the raw GRACE monthly solution. Here we use a bandwidth of 60
spherical harmonic degrees and a 0.5 degree buffer region. The solid
blue line is the best-fitting exponential trend. For more technical
details please see the Methods/Code
webpage. CLICK
HERE for a high resolution version of the published figure
from Harig and
Simons [2012]

Figure 2: Geographical pattern of the cumulative mass change over
Greenland for the period between 1/2003 and 1/2012. The integral value
"Int" for the entire epoch is shown in Gigatons. The zero cm water
contour shown in black. For more technical details please see
the Methods/Code
webpage. CLICK
HERE for a high resolution version of the published figure
from Harig and
Simons [2012]

Figure 3: Yearly-resolved maps of mass change over Greenland from
2003 to 2011. For every year we show the difference of the signal
estimated between January of that year and January of the next. The
integral values of the mass change per year are shown as "Int",
expressed in Gigatons. The zero cm/yr water contours are shown in
black. For more technical details please see
the Methods/Code
webpage. CLICK
HERE for a high resolution version of the published figure
from Harig and
Simons [2012]

References (see also Publications)

Harig, C. and F. J. Simons. Mapping Greeenland's mass loss in space
and time. *Proc. Natl. Acad. Sc.*, 109(49), 19934-19937. doi:10.1073/pnas.1206785109, 2012.