Kinematic GPS survey of geometry changes on Svalbard glaciers

The difficulty of using traditional direct mass-balance methods on large glaciers and ice caps requires the development of new methods. The objective of this paper is to evaluate whether a precise global positioning system (GPS) survey of geometry changes can be used to detect and monitor mass-balance changes. A joint project between Norway, Poland and Russia has investigated three high-altitude, large ice masses on Spitsbergen (Lomonosovfonna, Amundsenisen and Kongsvegen). The GPS survey was conducted using two methods. (1) Static GPS survey of stakes drilled into the ice was used for flow-velocity and emergence-velocity measurements. (2) Kinematic GPS survey was used to measure longitudinal profiles of surface elevation between the stakes. The accuracy of the measurements has proved to be better than 5 cm in horizontal position and 10 cm in height. Comparisons show that the GPS survey is applicable and gives sufficient accuracy to replace traditional methods and is thus especially useful on large glaciers where traditional surveying by electronic distance meter is impossible.