Svalbard ice cores and climate variability
In the project we have data from three different Svalbard ice core sites. These cores are providing information on the spatial variability component in addition to the temporal record. Most extensive work have been performed on the 1997 Lomonosovfonna ice core, drilled on the highest ice field on Svalbard 1250 m asl. Dating with an ice-flow model suggests that the core contains about 800 years of climate and environmental information. The ample evidence that the 1900s were the warmest century of at least the past 600 years, suggests that the older parts of the ice cores records should be less disturbed by melting and that the climate records from this time period have even better preserved information than the recent time period.
During the period from 1911 when instrumental meteorological data are available the ice core data from Lomonosovfonna have been thoroughly evaluated with respect to post-depositional alterations of the ice core record due to percolation of melt water For example, comparing the Lomonosovfonna 18O record to the instrumental record, we found that the overall pattern in the d18O records is similar to the Longyearbyen air temperature record. Thus, Svalbard ice cores generally provide proxies for winter conditions.
In 1998 and 1999, a Japanese team with Norwegian participants drilled two cores on the summit of Austfonna, at 600 m asl. The Austfonna ice cores have been analyzed at 25 cm resolution (equivalent to 1-10 years) for the same components as the Lomonosovfonna core, with the deepest core dating back to about 1200 AD.
The most recently drilled ice core is from Holtedahlfonna about 30 km NE from Ny Ålesund and was drilled in 2005. The core is 125 m and is estimated to cover the past 400 years, the uppermost 50 m is covering the 1900s. The elevation at the drill site is 1150 m asl.
In this project we are updating the core stratigraphy with shallow ice cores and snow pits to investigate the changes during the most recent years at these sites. We are also investigating the input of a variety of contaminants to these glaciers. Strong emphasis are given to the statistical exploration of the data sets.