CLIMATE CHANGE AND ECOSYSTEM IMPACTS ASSOCIATED WITH SHIFTS IN THE MID-LATITUDE STORM TRACK IN THE WESTERN UNITED STATES

Persistent Link:
http://hdl.handle.net/10150/194001
Title:
CLIMATE CHANGE AND ECOSYSTEM IMPACTS ASSOCIATED WITH SHIFTS IN THE MID-LATITUDE STORM TRACK IN THE WESTERN UNITED STATES
Author:
McAfee, Stephanie
Issue Date:
2009
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
One of the more robust 21st century projections from the most recent Intergovernmental Panel on Climate Change report (IPCC AR4) is a northward shift in the mean location of the Northern Hemisphere storm track. In the western United States, cool-season precipitation provides most of the water for domestic and industrial consumption, irrigation and power generation. In addition, winter precipitation is particularly effective in recharging soil moisture; as a result, it provides a strong control on the productivity of vegetation and on wildfire. Consequently, there is great interest in understanding 1) how changes in the storm track influence regional climate; 2) spatial and temporal variability in its impact; 3) how well general circulation models simulate the regional climate dynamics that bring precipitation to the West; and 4) whether errors in climate simulation might impact assessment of ecological changes. In order to investigate climate change in the western United States associated with shifts in the storm track, I analyzed the relationship between climate and the Northern Annular Mode (NAM). When the storm track is displaced to the north, there is an earlier transition to warm-season circulation patterns and weather conditions. However, the relationship between the winter NAM and climate is not stable over time. Further analysis identified changes in the correlations between the NAM and tree-ring width, precipitation and temperatures associated with changes in the phase of the Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation. Examining 18 of the IPCC AR4 coupled climate models demonstrated cool-season precipitation errors approaching 300% over western North America. These errors are related to difficulties in representing orography, given the coarse resolution of models, and they may influence the quality of precipitation projections into the future. A simple test using the Köppen classification system found that these precipitation errors lead to underestimating the area of the United States in dryland ecosystem types by up to 89% and consequently allowed for much greater expansion of dryland in the future than is actually likely. These studies suggest that the West is likely to experience greater drought in the future. However, no single tool can yet quantify that change.
Type:
text; Electronic Dissertation
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Geosciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Russel, Joellen; Overpeck, Jonathan
Committee Chair:
Russel, Joellen

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleCLIMATE CHANGE AND ECOSYSTEM IMPACTS ASSOCIATED WITH SHIFTS IN THE MID-LATITUDE STORM TRACK IN THE WESTERN UNITED STATESen_US
dc.creatorMcAfee, Stephanieen_US
dc.contributor.authorMcAfee, Stephanieen_US
dc.date.issued2009en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractOne of the more robust 21st century projections from the most recent Intergovernmental Panel on Climate Change report (IPCC AR4) is a northward shift in the mean location of the Northern Hemisphere storm track. In the western United States, cool-season precipitation provides most of the water for domestic and industrial consumption, irrigation and power generation. In addition, winter precipitation is particularly effective in recharging soil moisture; as a result, it provides a strong control on the productivity of vegetation and on wildfire. Consequently, there is great interest in understanding 1) how changes in the storm track influence regional climate; 2) spatial and temporal variability in its impact; 3) how well general circulation models simulate the regional climate dynamics that bring precipitation to the West; and 4) whether errors in climate simulation might impact assessment of ecological changes. In order to investigate climate change in the western United States associated with shifts in the storm track, I analyzed the relationship between climate and the Northern Annular Mode (NAM). When the storm track is displaced to the north, there is an earlier transition to warm-season circulation patterns and weather conditions. However, the relationship between the winter NAM and climate is not stable over time. Further analysis identified changes in the correlations between the NAM and tree-ring width, precipitation and temperatures associated with changes in the phase of the Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation. Examining 18 of the IPCC AR4 coupled climate models demonstrated cool-season precipitation errors approaching 300% over western North America. These errors are related to difficulties in representing orography, given the coarse resolution of models, and they may influence the quality of precipitation projections into the future. A simple test using the Köppen classification system found that these precipitation errors lead to underestimating the area of the United States in dryland ecosystem types by up to 89% and consequently allowed for much greater expansion of dryland in the future than is actually likely. These studies suggest that the West is likely to experience greater drought in the future. However, no single tool can yet quantify that change.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorRussel, Joellenen_US
dc.contributor.advisorOverpeck, Jonathanen_US
dc.contributor.chairRussel, Joellenen_US
dc.contributor.committeememberRussel, Joellenen_US
dc.contributor.committeememberOverpeck, Jonathanen_US
dc.contributor.committeememberWoodhouse, Connieen_US
dc.contributor.committeememberFlessa, Karlen_US
dc.contributor.committeememberBetancourt, Julioen_US
dc.identifier.proquest10533en_US
dc.identifier.oclc752260920en_US
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