Greenland - Release Level 04 (RL-04) (Go to RL-05)
These are updated results continued from our paper Harig and Simons [2012]. They use the Release level 4 UTCSR (http://www.csr.utexas.edu/grace/) data solutions from April 2002 up to and including April 2012. Since the RL04 series has been discontinued, these results represent our final RL04 update, and additional updates will be done on the RL05 Greenland page. This page is kept more as a historical purpose and RL05 should be used for scientific purposes since they are inproved monthly solutions.

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 2002. The latest RL04 trend estimate increased to -212 Gigatons per year by using more RL04 months from September 2011 to April 2012.
Total Trend
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]
In the updated total map below, we see that the overall cumulative pattern of mass change over the last 10 years is smiliar to each year. You can see in Figure 3 that the mass change for 2011 follows the general pattern for the previous years, so we would not expect big changes in the 10 year pattern. Note the increased scale bar in this figure compared to the previous published figure shows the increase in magnitudes for both melt on the coasts and changes in the high elevation interior.
Total Map
Figure 2: Geographical pattern of the cumulative mass change over Greenland for the period between 1/2003 and 1/2011. 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]
Below are the mass loss maps for each year, updated through 2011. We can see that 2011 was a record year for ice melt in Greenland. Nearly all coastal areas experienced mass loss and at much higher rates of loss (deeper reds) than previous years. In addition, the middle of Greenland shows increased mass accumulation, with magnitudes of over 20 cm/yr of water equivalent. (Note: this last conclusion is not as strong in RL05 data.)
Yearly Maps
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 About/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.