NORSAR’s extensive network of infrasound and seismic stations has proven to provide novel observations of weather and climate related phenomena both in the atmosphere and the cryosphere, such as in glaciers.
Regarding the atmosphere, one of the world’s most modern and advanced infrasound stations, called IS37, was installed in 2013 in Bardufoss, northern Norway. This station is part of the global system for monitoring compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), and its primary goal is to detect possible atmospheric nuclear explosions.
However, the observed infrasound wavefield at IS37, originating from various natural and man-made sources, has given us data which provide unique information about the state and dynamics of the middle and upper atmosphere. Direct observations of winds and temperatures at these high altitudes are rare and are to a large extent ignored in weather and climate models. NORSAR has therefore established a program for research on infrasound and other technologies aiming at improving the models of the middle and upper atmosphere. In these studies, data from IS37 is supplemented with observations at several smaller infrasound stations in the region, as well as with other stations of the global CTBT network.
Seismic signals from glaciers
Seasonal and more long-term temperature variations influence the dynamics of glaciers and large ice-sheets like those found on Greenland, on Svalbard and in the Antarctica. Glacial movements and calving generate both seismic signals propagating underground and acoustic (sound) signals in the air which are observable by highly sensitive permanent and mobile instrumentation.
For example, several studies conducted by NORSAR scientists have addressed the occurrence of so-called ice-quakes and other glacial phenomena both in the Arctic and the Antarctic regions. The spatial-temporal distribution and characteristics of these phenomena are strongly correlated with weather and climate in the Polar Regions. The long time-series provided by NORSAR’s networks and mobile instrumentation provide key information for such studies.