A message sent out on cryolist:
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Dear all,
On behalf of a number of colleagues and collaborators we would like to alert you to an unusually early melt event over the Greenland ice sheet this week.
We calculate around 11.8% of the area of the ice sheet melted yesterday and according to our analysis (back to 1990, we will extend this back to 1980 shortly), this is a full month earlier over such a large area (more than 10% of the ice sheet) than has occurred previously.
Observations from Greenland show that for example, Kangerlussuaq measured 17.8C (only 0.2C off the record temperature measured for the whole of Greenland in April) and Summit station -6.6C, a new record for April. PROMICE station KAN_U showed a daily mean temperature of 0.5C with a maximum hourly temperature of 3.05C, most of the lower PROMICE stations recorded temperatures between 5 and 10C.
The culprit driving melt at this time is an interesting omega pressure pattern with a very cold north America and warm air over Greenland.
We have assembled some information from AWS, radiosondes and models in the attached pdf document to explain the context of this strange start to the melt season in 2016. As usual, since 2013, daily updated surface mass balance plots, and PROMICE observations as well as GRACE total mass balance can all be viewed here (in English):
http://polarportal.dk/en/groenlands-indlandsis/nbsp/isens-overflade/ Data and model output is available for research purposes.
On behalf of Polar Portal scientists at DMI, DTU and GEUS,
Best wishes
Ruth Mottram