TY - BOOK

T1 - Advanced methods of glaciological modelling and time series analysis.

AU - Grinsted, Aslak

PY - 2006

Y1 - 2006

N2 - This thesis covers a wide range of methods and research subjects and is thus broad inscope. The methods are applied to ice cores, Antarctic blue ice areas, sea level, and largescale climate variability.Two new ice core proxies for continentality and summer melt were developed for theLomonosovfonna ice core, central Svalbard. The melt proxy was based on thepreferential washout different ions and the continentality proxy on the amplitudes of theannual signal in d18O. These proxies suggest that summers in the Barents region were aswarm (or warmer) than the present during the medieval warm period. A high qualitychemical record of environmental changes was proven to be preserved in the core.A simple and flexible flow model based on the continuity equation was developedwith the purpose of dating the ancient surface ice in Antarctic blue ice areas. The modelhas been applied to three very different ice fields in East and West Antarctica.The wavelet coherence and singular spectrum analysis methods were advanced and aphase-aware teleconnections method was developed. The methods were utilized inisolating a ~14 year quasi-periodic component in multiple climate series from the Arcticand the equatorial Pacific. It was determined that the signals shared a common source anda linking mechanism was found. The same techniques were applied for signalenhancement in ground penetrating radar.The proposed wide spread influence of decadal solar variability on climate wasscrutinized and it was concluded that the 11-year cycle sometimes seen in climate proxyrecords 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 the1990s. The impact of major volcanic eruptions on global sea level was studied and it wasfound that a disturbance of the global water cycle causes a rise in sea level in the firstyear following an eruption.

AB - This thesis covers a wide range of methods and research subjects and is thus broad inscope. The methods are applied to ice cores, Antarctic blue ice areas, sea level, and largescale climate variability.Two new ice core proxies for continentality and summer melt were developed for theLomonosovfonna ice core, central Svalbard. The melt proxy was based on thepreferential washout different ions and the continentality proxy on the amplitudes of theannual signal in d18O. These proxies suggest that summers in the Barents region were aswarm (or warmer) than the present during the medieval warm period. A high qualitychemical record of environmental changes was proven to be preserved in the core.A simple and flexible flow model based on the continuity equation was developedwith the purpose of dating the ancient surface ice in Antarctic blue ice areas. The modelhas been applied to three very different ice fields in East and West Antarctica.The wavelet coherence and singular spectrum analysis methods were advanced and aphase-aware teleconnections method was developed. The methods were utilized inisolating a ~14 year quasi-periodic component in multiple climate series from the Arcticand the equatorial Pacific. It was determined that the signals shared a common source anda linking mechanism was found. The same techniques were applied for signalenhancement in ground penetrating radar.The proposed wide spread influence of decadal solar variability on climate wasscrutinized and it was concluded that the 11-year cycle sometimes seen in climate proxyrecords 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 the1990s. The impact of major volcanic eruptions on global sea level was studied and it wasfound that a disturbance of the global water cycle causes a rise in sea level in the firstyear following an eruption.

M3 - Ph.D. thesis

SN - 952-484-054-5

T3 - Arctic Centre Reports

BT - Advanced methods of glaciological modelling and time series analysis.

PB - Lapin Yliopisto

CY - Rovaniemi, Finland

ER -