NSF Org:	AGS Division of Atmospheric and Geospace Sciences
Recipient:
Initial Amendment Date:	January 28, 2015
Latest Amendment Date:	January 12, 2016
Award Number:	1433290
Award Instrument:	Fellowship Award
Program Manager:	Eric DeWeaver edeweave@nsf.gov  (703)292-8527 AGS  Division of Atmospheric and Geospace Sciences GEO  Directorate for Geosciences
Start Date:	February 1, 2015
End Date:	January 31, 2017 (Estimated)
Total Intended Award Amount:	$86,000.00
Total Awarded Amount to Date:	$172,000.00
Funds Obligated to Date:	FY 2015 = $86,000.00 FY 2016 = $86,000.00
History of Investigator:	John Dwyer (Principal Investigator)
Recipient Sponsored Research Office:	Dwyer John G New York NY  US  10027-0000
Sponsor Congressional District:
Primary Place of Performance:	Massachusetts Institute of Technology Cambridge MA  US  02139-4301
Primary Place of Performance Congressional District:	07
Unique Entity Identifier (UEI):
Parent UEI:
NSF Program(s):	Climate & Large-Scale Dynamics, Postdoctoral Fellowships
Primary Program Source:	01001516DB NSF RESEARCH & RELATED ACTIVIT 01001617DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s):	4444, 5740, 7137, OTHR
Program Element Code(s):	574000, 713700
Award Agency Code:	4900
Fund Agency Code:	4900
Assistance Listing Number(s):	47.050

ABSTRACT

This award provides funds for a 2-year Postdoctoral Research Fellowship for the PI, who will work under the mentorship of Professor Paul O'Gorman at the Massachussetts Institute of Technology. The research topic is the effect of sea ice loss on atmospheric circulation and extreme weather in the middle latitudes of the Northern Hemisphere. Three issues in the atmospheric response to sea ice decline are considered: 1) The location, strength, seasonality, and variability of the eddy-driven jet and associated storm tracks, as well as the dominant modes of atmospheric variability such as the Northern Annular Mode; 2) The propagation of atmospheric waves and eddies, and atmospheric blocking patterns; and 3) Extreme weather phenomena such as heat waves, cold spells, extreme precipitation, droughts, and intense extratropical cyclones. The research is conducted through analysis of observations and climate model simulations of sea ice decline and atmospheric circulation change. A hierarchy of models at varying levels of complexity is used to identify and isolate specific climate processes that determine the atmospheric response to sea ice loss. Factors to be considered include a possible relationship between sea ice loss and the mean available potential energy of the midlatitude atmosphere, the reduction in pole-to-equator temperature gradient accompanying sea ice loss, and changes in the timing of the seasonal cycle.

The work has broader impacts given the societal consequences of extreme weather events and the benefits that would come for a better understanding of how these events may change due to the dramatic loss of sea ice in the Arctic. In addition, the project supports a postdoctoral researcher who is at the beginning of his scientific career, thereby providing for the future scientific workforce in this area. An undergraduate student will also be engaged in the research and mentored by the PI.

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

Precipitation extremes intensify with global warming in observations and simulations, but changes in their duration or spatial extent are not well understood. These extreme precipitation events can cause severe flooding and have a very large societal and economic cost. Improving our understanding of these extreme events could help emergency planners and managers better prepare. Using state-of-the-art, comprehensive climate models we found that the duration of midlatitude precipitation extremes is expected to decrease over the 21st century, although the magnitude of the decrease is less than 1%/K when averaged across the models. This is a smaller effect than the roughly 7%/K increase in the intensity of extreme precipitation. We also found that the duration of precipitation extremes is linked to a time scale given by the spatial extent of the extreme events divided by the average wind speed. This scale describes the duration in terms of the climatology, differences between models, and differences in response to climate change. In simulations with an idealized climate model, a stronger equator-to-pole temperature difference decreases the duration despite increases in the zonal length of events. This is due to a relatively larger strengthening of the midlatitude winds by the thermal wind relation compared to an increasing Rossby deformation radius.

 

Last Modified: 03/28/2017
Modified by: John G Dwyer

Please report errors in award information by writing to: awardsearch@nsf.gov.