Land ice

Progress (May 2018)

We have recently produced our first mass balance trends results for Greenland using the BHM framework. However, applying a method developed for Antarctica (in the RATES project) to Greenland has proved more complex than we anticipated. This is mainly because the nature of the processes that govern ice accumulation and melt are very different, requiring them to be incorporated differently and necessitating much code to be rewritten.

Figure 2. Comparison of our current BHM mass trend result (black line) with the weighted mean (white line) and range (orange bars) of other published studies

While the overall mass trend now appears sensible (and fits well against other published studies), a ‘source separation’ issue remains whereby the BHM is not allocating the total change correctly between the two main contributory processes, ice dynamics and surface mass balance. Work is ongoing to develop a method for better separating these processes and to therefore provide more robust results at both ice sheet and basin scales.

Progress (April 2018)

Considerable progress has been made with regards to using a BHM approach to understand ice mass trends for Antarctica and Greenland. Using a BHM framework allows us to produce statistically-rigorous estimates of ice sheet mass balance and the contribution of component parts at the drainage basin scale. Error-bounded estimates of Antarctic ice mass balance trends have now been obtained for 2003 to 2015 (an update of RATES project), and we have recently started to apply the BHM framework to explore mass balance trends for Greenland.

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