Greenland Exam

Question 1

Introduction

Answer 1

The surface mass balance of the Greenland ice sheet is essentially the mass gained from solid accumulation minus the mass lost from meltwater runoff, with evaporation and sublimation being negligible (Box et al., 2006).

Question 2

Effect of temperature (melt)

Answer 2

A rise = enhanced surface melting and run-off occurs.

The ablation that occurs means the basal region of the glaciers is exposed to the greatest amounts of surface water.

Melting of surface snow may occur at elevations of about 1,300 m in north Greenland, whilst up to 2,700 m in south Greenland (Diamond, 1960).

Question 3

The individual basins response to heat is therefore likely to be characteristic of what?

Answer 3

Its topography, atmospheric circulation and latitudinal gradient (Sicart et al., 2008).

Question 4

Effect of sea contact

Answer 4

Enhanced melting caused due to rising ocean temperatures which causes glaciers to thin (Rignot et al., 2008).

North/North-Eastern basins of Greenland border the Arctic Ocean

South and Western basins border the warmer Atlantic Ocean.

Question 5

The mass balance of the polar ice sheets is affected by numerous factors, including…

Answer 5

Changes in precipitation and snowfall patterns

Summer melting of snow

Changes in ice sheet albedo

Changes in the extent of supraglacial lakes

Submarine melting of the floating ice shelves at the tongue of marine outlet glaciers (Wouters et al., 2015)

Icebergs breaking off of glaciers

Question 6

Greenland is losing mass…

Answer 6

34 billion tonnes lost per year over the period 1992–2001 to 215 billion tonnes lost per year over the period 2002–2011.

In 2012, an exceptional loss estimated at more than 500 billion tonnes was recorded.

Question 7

From 1992 to 2012, the contribution to the global sea level has been estimated to have been approximately…

Answer 7

8.0 mm

Question 8

Atmospheric effects

Answer 8

The increased melting has been attributed to changes in general circulation in summer, creating warmer conditions over Greenland

(Fettweis et al., 2013)

Question 9

Having said this, a warmer climate can arguably cause…

Answer 9

Increased atmospheric moisture content, the effect of this being an increase in solid accumulation.