This thesis covers a wide range of methods and research subjects and is thus broad in
scope. The methods are applied to ice cores, Antarctic blue ice areas, sea level, and large
scale climate variability.
Two new ice core proxies for continentality and summer melt were developed for the
Lomonosovfonna ice core, central Svalbard. The melt proxy was based on the
preferential washout different ions and the continentality proxy on the amplitudes of the
annual signal in d18O. These proxies suggest that summers in the Barents region were as
warm (or warmer) than the present during the medieval warm period. A high quality
chemical record of environmental changes was proven to be preserved in the core.
A simple and flexible flow model based on the continuity equation was developed
with the purpose of dating the ancient surface ice in Antarctic blue ice areas. The model
has been applied to three very different ice fields in East and West Antarctica.
The wavelet coherence and singular spectrum analysis methods were advanced and a
phase-aware teleconnections method was developed. The methods were utilized in
isolating a ~14 year quasi-periodic component in multiple climate series from the Arctic
and the equatorial Pacific. It was determined that the signals shared a common source and
a linking mechanism was found. The same techniques were applied for signal
enhancement in ground penetrating radar.
The proposed wide spread influence of decadal solar variability on climate was
scrutinized and it was concluded that the 11-year cycle sometimes seen in climate proxy
records is unlikely to be driven by solar forcing.
Global sea level was reconstructed from tide gauge data using a new ‘virtual station’
method. The 1920-1945 rate of sea level rise was as large as the rate observed during the
1990s. The impact of major volcanic eruptions on global sea level was studied and it was
found that a disturbance of the global water cycle causes a rise in sea level in the first
year following an eruption.