Greenland meltdown

fter a record-breaking 2010 in terms of surface melt area in Greenland [Tedesco et al, 2011], numbers from 2011 have been eagerly awaited. Marco Tedseco and his group have now just reported their results. This is unrelated to other Greenland meltdown this week that occurred at the launch of the new Times Atlas.
The melt index anomaly is the number of days with detectable surface melt compared to the baseline period of 1979-2010. The higher the number, the more melt days there were. While this did not match the record 2010 levels, depending on the analysis 2011 was either the 3rd or 6th year in the rankings.
Analysis of the surface mass balance via regional modelling demonstrates that there has been an increasing imbalance between snowfall and runoff over recent years, leading to a lowering of ice elevation, even in the absence of dynamical ice effects (which are also occurring, mostly near the ice sheet edge).


Figure 2. Regional model-based estimates of snowfall (orange), surface melt and runoff (yellow) and the net accumulation (Gt/yr) (blue) since 1958.
The estimated 2010 or 2011 surface mass imbalance (~300 Gt/yr) is comparable to the GRACE estimates of the total mass loss (which includes ice loss via dynamic effects such as the speeding up of outlet glaciers) of 248 ± 43 Gt/yr for the years 2005-2009 [Chen et al, 2011]. Data for 2010 and 2011 will thus be interesting to see.

Continue Reading: http://www.realclimate.org/index.php/archives/2011/09/greenland-meltdown/