By Clare Boston
Developments in remote sensing during the last 30 years have greatly increased the spatial resolution of satellite and airborne images, producing a wealth of remotely sensed products of unprecedented accuracy. This information is becoming increasingly relied on for monitoring snow and ice cover in the Arctic following a decline in meteorological observations on the ground. In Geography Compass, Allan Frei discusses this increasing importance for assessing changes in snow cover in the northern hemisphere. He considers the use of remote sensing in climatological analyses and assesses the use of these observations to calibrate the representation of snow in climate models.
However, data from a recent expedition to the Arctic demonstrates the ongoing need for ground observations. The Catlin Arctic Survey, as it is known, undertaken between March and May this year, provides new information on ice thickness, currently unavailable from satellite data. This data suggests that if current trends continue, the Arctic Ocean could be ice-free in the summer within as little as 20 years, demonstrating that both remotely sensed and ground observations in the Arctic hold important implications for future climate modelling in the region.
Geography Directions 
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