Department of Climate and Space Sciences and Engineering in the College of Engineering at the University of Michigan

CLaSP Special Seminar - Dr. Ashley Payne

Date: January 23, 2018
Time: 3:30 pm - 4:30 pm
Location: SRB Auditorium, room 2246

Title: "Atmospheric Rivers over the North Pacific"

Abstract: Research over the last decade has highlighted the essential role that atmospheric rivers play in the hydrology of the United States, particularly in their ability to result in prolonged periods of extreme precipitation. Atmospheric rivers are filamentary features with high water vapor transport in the lower troposphere that are found in major basins globally and serve as a major mechanism of poleward mid-latitude moisture transport. Landfalling atmospheric rivers are linked to heavy precipitation and extreme flooding, most notably along the western coast of North America. However, despite their importance, models struggle to provide medium to long-term forecasts of atmospheric river characteristics such as landfall location, intensity and the amount and timing of precipitation. An investigation of the large-scale mechanisms influencing their behavior prior to landfall is essential to improving the ability to forecast hydrologically significant landfalling events.
I will show that characteristics such as atmospheric river intensity and duration along the coastline are ultimately modulated by large-scale extratropical dynamics. In particular, I will demonstrate that a close relationship exists between atmospheric river intensity at landfall and an increase in the frequency of an cyclonic Rossby wave breaking over the eastern North Pacific. Persistent atmospheric river events lasting more than 60 hours along the coastline show distinct differences from the climatology of all other landfalling atmospheric rivers and are characterized not only by a strengthened and eastward shifted an cyclonic Rossby wave breaking signature, but also by an over-all increase in atmospheric moisture. I will also examine the influence of climate change on atmospheric river behavior using 28 different models participating in CMIP5. This work highlights the potential for future efforts to investigate the driving mechanisms behind the formation and development of atmospheric rivers with the goal of improving medium to long-term forecasts of their intensity at landfall. 

Biography: Dr. Ashley Payne is currently a fellow of the University of Michigan’s President’s Postdoctoral Fellowship Program working with Christiane Jablonowski in the Department of Climate and Space Sciences and Engineering. She completed her M.S. (2012) and Ph.D. (2016) in Earth System Science at the University of California, Irvine, advised by Gudrun Magnusdottir. Prior to graduate school, she worked with Jay Banner and Dan Breecker at the University of Texas on a project centered on understanding the CO2 in Central Texas cave air. She graduated from the University of Texas in 2010 with a B.Sc. in geoscience.​ ​Dr. Payne is interested in using observations and reanalysis datasets to investigate the impacts, characteristics and climatology of extreme weather events. She uses process-based studies to evaluate models and employ simple perturbation experiments to develop a mechanistic understanding of weather extremes and their response to climate change.

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