Doctoral Dissertation Research: Understanding the Climate Mechanisms Associated with Past Drought and Vegetation Change.

University Of Utah, Salt Lake City UT

Investigators

Abstract

NATIONAL SCIENCE FOUNDATION GEOGRAPHY SPATIAL SCIENCES (GSS) PROGRAM ABSTRACT This doctoral dissertation research project will use the modern climate analog technique to investigate the synoptic and dynamic climate processes associated with drought in the western U.S. and the possible responses of ecosystems to past megadroughts. The doctoral student will provide new insights into how vegetative responses to past hydroclimate variability and disturbances can help protect and mitigate ecological communities against future environmental change. An understanding of the climate processes associated with modern drought will provide deeper insights into past drought variability and the mechanisms that caused megadroughts evident in paleoecological records. The student will work closely with local communities and government agencies by providing useful knowledge to resource managers regarding past hydroclimate variability and impacts to valuable natural resources. In addition, the new insights into biodiversity dynamics associated with past megadroughts will inform policy-related discussions regarding ecological sustainability and land-management issues. Results from this research would be useful for a broad range of uses, including species range modeling, predicting future ecosystem migration patterns in response to future climate change, and fire management in certain ecosystems. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career. Understanding the range of natural variability related to past drought and wet periods is important for providing context to water resource managers for future water planning. The doctoral student whose dissertation research will be supported by this award will use modern climate data during past dry and wet events as analogs for the events seen in the sedimentary record. The project will focus on two core questions: (1) What were the prevailing seasonal atmospheric circulation patterns and surface conditions over western North America during the megadrought centered around 4,200 years BP? (2) What were the prevailing seasonal atmospheric circulation patterns over western North America during the wet event that followed the megadrought? In order to identify possible synoptic and dynamic patterns that may have caused these two events in the western U.S., the student will apply a modern climate analog technique, which is a conceptual model that uses modern extremes as analogs of past events. To accomplish this, a composite of anomaly values for selected modern climate analog case years will be mapped and analyzed for their spatiotemporal variability of surface and atmospheric conditions.