Past climate variability: model analysis and proxy intercomparison
This thesis investigates the climate variability of the late Quaternary (21 000 yrs BP to present day) using model simulations and proxy data. The thesis consists of four manuscripts and one appendix. In the first two manuscripts and the appendix I, the extratropical Northern Hemisphere atmospheric...
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ftunivbergen:oai:bora.uib.no:1956/9433 2023-05-15T16:40:46+02:00 Past climate variability: model analysis and proxy intercomparison Pausata, Francesco S. R. 2015-02-24T14:48:50Z application/pdf https://hdl.handle.net/1956/9433 eng eng The University of Bergen Paper I: Pausata, F. S. R., Li, C., Wettstein, J. J., Nisancioglu, K. H., and Battisti, D. S.: Changes in atmospheric variability in a glacial climate and the impacts on proxy data: a model intercomparison. Clim. Past, 5, 489-502 (2009). The article is available at: http://hdl.handle.net/1956/9430 Paper II: Pausata, F. S. R., Li, C., Wettstein, J. J., Nisancioglu, K. H., Kageyama, M.: The key role of topography in altering North Atlantic atmospheric circulation during the last glacial period. Clim. Past, 7, 1089 -1101 (2011). The article is available at: http://hdl.handle.net/1956/9431 Paper III: Andersson, C., Pausata, F. S. R., Jansen, E., Risebrobakken, B., and Telford, R. J.: Holocene trends in the foraminifer record from the Norwegian Sea and the North Atlantic Ocean. Clim. Past, 6, 179-193 (2010). The article is available at: http://hdl.handle.net/1956/9432 Paper IV: Pausata, F. S. R., Battisti D. S., Nisancioglu, K. H., Bitz C.: Eastern Chinese stalagmites: proxies for Indian Summer Monsoon during abrupt climate changes. Published as: Chinese stalagmite δ18O controlled by changes in the Indian monsoon during a simulated Heinrich event. Nature Geosci, 4(7), 474-480.The article is not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1038/ngeo1169 urn:isbn:978-82-308-1624-0 https://hdl.handle.net/1956/9433 cristin:295289 Copyright the author. All rights reserved Doctoral thesis 2015 ftunivbergen https://doi.org/10.1038/ngeo1169 2023-03-14T17:42:14Z This thesis investigates the climate variability of the late Quaternary (21 000 yrs BP to present day) using model simulations and proxy data. The thesis consists of four manuscripts and one appendix. In the first two manuscripts and the appendix I, the extratropical Northern Hemisphere atmospheric circulation in different Quaternary time slices (preindustrial, PI, 1750 AD; Mid Holocene, MH, 6 kyrs BP; Last Glacial Maximum, LGM, 21 kyrs BP) is investigated using different climate models. The contributions of greenhouse gases, ice-sheet topography and albedo on the atmospheric mean climate and its variability are analyzed. In general, the models show no major changes in atmospheric circulation nor in its interannual variability in a climate slightly warmer (MH) than the PI one. In the LGM simulations, the models show decreased sea level pressure interannual variability relative to PI; on the other hand, the interannual variability of surface temperature is increased. The leading mode of sea level pressure variability in the North Atlantic is characterized by a NAO-like behavior in all climate states; however, it represents less total variance and the centers of action are weaker at the LGM. The presence of the Laurentide ice-sheet over North America during the LGM accounts for most of the changes observed in the LGM climate. Finally, the models show that the link between atmospheric and surface climate (temperature and precipitation) variability is altered in a glacial climate compared to the PI. Therefore, assuming present-day climate-proxy relationships when interpreting proxy records may well lead to a misinterpretation of past climates. The results of the first manuscript point out that certain proxies may record seasonal rather than annual climate changes or that they could be tape recorders for climate changes far afield rather than local. These issues are tackled in the second and third manuscripts. In paper III, various marine proxy records from the North Atlantic Ocean that spann the Holocene (10-0 kyrs ... Doctoral or Postdoctoral Thesis Ice Sheet North Atlantic University of Bergen: Bergen Open Research Archive (BORA-UiB) Nature Geoscience 4 7 474 480 |
institution |
Open Polar |
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University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
description |
This thesis investigates the climate variability of the late Quaternary (21 000 yrs BP to present day) using model simulations and proxy data. The thesis consists of four manuscripts and one appendix. In the first two manuscripts and the appendix I, the extratropical Northern Hemisphere atmospheric circulation in different Quaternary time slices (preindustrial, PI, 1750 AD; Mid Holocene, MH, 6 kyrs BP; Last Glacial Maximum, LGM, 21 kyrs BP) is investigated using different climate models. The contributions of greenhouse gases, ice-sheet topography and albedo on the atmospheric mean climate and its variability are analyzed. In general, the models show no major changes in atmospheric circulation nor in its interannual variability in a climate slightly warmer (MH) than the PI one. In the LGM simulations, the models show decreased sea level pressure interannual variability relative to PI; on the other hand, the interannual variability of surface temperature is increased. The leading mode of sea level pressure variability in the North Atlantic is characterized by a NAO-like behavior in all climate states; however, it represents less total variance and the centers of action are weaker at the LGM. The presence of the Laurentide ice-sheet over North America during the LGM accounts for most of the changes observed in the LGM climate. Finally, the models show that the link between atmospheric and surface climate (temperature and precipitation) variability is altered in a glacial climate compared to the PI. Therefore, assuming present-day climate-proxy relationships when interpreting proxy records may well lead to a misinterpretation of past climates. The results of the first manuscript point out that certain proxies may record seasonal rather than annual climate changes or that they could be tape recorders for climate changes far afield rather than local. These issues are tackled in the second and third manuscripts. In paper III, various marine proxy records from the North Atlantic Ocean that spann the Holocene (10-0 kyrs ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Pausata, Francesco S. R. |
spellingShingle |
Pausata, Francesco S. R. Past climate variability: model analysis and proxy intercomparison |
author_facet |
Pausata, Francesco S. R. |
author_sort |
Pausata, Francesco S. R. |
title |
Past climate variability: model analysis and proxy intercomparison |
title_short |
Past climate variability: model analysis and proxy intercomparison |
title_full |
Past climate variability: model analysis and proxy intercomparison |
title_fullStr |
Past climate variability: model analysis and proxy intercomparison |
title_full_unstemmed |
Past climate variability: model analysis and proxy intercomparison |
title_sort |
past climate variability: model analysis and proxy intercomparison |
publisher |
The University of Bergen |
publishDate |
2015 |
url |
https://hdl.handle.net/1956/9433 |
genre |
Ice Sheet North Atlantic |
genre_facet |
Ice Sheet North Atlantic |
op_relation |
Paper I: Pausata, F. S. R., Li, C., Wettstein, J. J., Nisancioglu, K. H., and Battisti, D. S.: Changes in atmospheric variability in a glacial climate and the impacts on proxy data: a model intercomparison. Clim. Past, 5, 489-502 (2009). The article is available at: http://hdl.handle.net/1956/9430 Paper II: Pausata, F. S. R., Li, C., Wettstein, J. J., Nisancioglu, K. H., Kageyama, M.: The key role of topography in altering North Atlantic atmospheric circulation during the last glacial period. Clim. Past, 7, 1089 -1101 (2011). The article is available at: http://hdl.handle.net/1956/9431 Paper III: Andersson, C., Pausata, F. S. R., Jansen, E., Risebrobakken, B., and Telford, R. J.: Holocene trends in the foraminifer record from the Norwegian Sea and the North Atlantic Ocean. Clim. Past, 6, 179-193 (2010). The article is available at: http://hdl.handle.net/1956/9432 Paper IV: Pausata, F. S. R., Battisti D. S., Nisancioglu, K. H., Bitz C.: Eastern Chinese stalagmites: proxies for Indian Summer Monsoon during abrupt climate changes. Published as: Chinese stalagmite δ18O controlled by changes in the Indian monsoon during a simulated Heinrich event. Nature Geosci, 4(7), 474-480.The article is not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1038/ngeo1169 urn:isbn:978-82-308-1624-0 https://hdl.handle.net/1956/9433 cristin:295289 |
op_rights |
Copyright the author. All rights reserved |
op_doi |
https://doi.org/10.1038/ngeo1169 |
container_title |
Nature Geoscience |
container_volume |
4 |
container_issue |
7 |
container_start_page |
474 |
op_container_end_page |
480 |
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1766031176280047616 |