| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
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| Initial Amendment Date: | March 24, 2017 |
| Latest Amendment Date: | April 1, 2019 |
| Award Number: | 1640452 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Eric DeWeaver
edeweave@nsf.gov (703)292-8527 AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | April 1, 2017 |
| End Date: | March 31, 2022 (Estimated) |
| Total Intended Award Amount: | $539,093.00 |
| Total Awarded Amount to Date: | $539,093.00 |
| Funds Obligated to Date: |
FY 2018 = $185,712.00 FY 2019 = $185,041.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
21 N PARK ST STE 6301 MADISON WI US 53715-1218 (608)262-3822 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
1225 W Dayton St Madison WI US 53706-1612 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Climate & Large-Scale Dynamics |
| Primary Program Source: |
01001819DB NSF RESEARCH & RELATED ACTIVIT 01001920DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Winter storms have significant societal and economic impacts in North America. For over 50 years, forecasters have noted that the location of the southern extent of pre-existing snow cover appears to affect the tracks and intensity of storms that follow afterwards. However, neither the validity nor the physical mechanisms underlying this forecasting rule-of-thumb have been rigorously investigated. Understanding how and where these storms form, both currently and in the future, in relation to the snow line, requires advances in theories and models of large-scale climate dynamics. This project will conduct a comprehensive statistical analysis of a greater range of snow cover and cyclone observations in central/eastern North America, and evaluate hypotheses of the underlying mechanisms using numerical model simulations. These findings will then be used to address how this process is represented in climate models and identify changes to mid-latitude storm trajectories arising from past and projected retreats and advances of the mid-latitude snow line.
Better understanding of how features of the Earth system, particularly snow cover, manifest in weather systems, will lead to improvements in both weather and climate forecasting and benefit risk management of weather hazards. New databases on snow cover and mid-latitude storm tracks will be made publicly and freely available. This project supports a PhD student and two undergraduate students who will be trained in the emerging field of the weather-climate interface.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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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.
Winter storms have significant impacts in North America. Prior observational studies have shown that the location of the southern extent of pre-existing snow cover appears to affect the tracks and intensity of these winter storms, also known as mid-latitude cyclones. Here, we conducted a modeling study to investigate the role that this snow cover has on the projected forecasts of mid-latitude cyclones.
Climate model projections project a poleward shift in storm tracks by the late 21st century and a coincident poleward retreat of the snow cover. We applied a method to impose projected snow retreat in the 21st century from the Coupled Model Intercomparison Project Phase Five (CMIP5) to model the effect of snow retreat on 20 historical cold season cyclone cases as they tracked over the North American Great Plains. The ensemble of simulations was conducted with the Weather Research and Forecast Model. We found that while cyclone trajectories shifted poleward and their central sea level pressure deepened, they did not change substantially. Snow retreat did favor stronger increases in near-surface wind speed and precipitation, with a greater fraction of rain over snow, and poleward shifts in cyclone-associated precipitation. These responses were larger in mid-winter than the shoulder months.
A detailed analysis of storm structure reveals opposing mechanisms that constrain this effect. Diagnosis of the potential vorticity field isolates how changes in surface temperature, static stability, and relative vorticity affect the developing cyclone. The surface warm anomaly lowered heights and strengthened cyclonic circulation.This effect, however, is mitigated by the stability response. A similar results was seen in diagnosis of Arctic storms with sea ice margin retreat in a large ensemble of climate model simulations.
Our findings lend insight into improvements in forecasting of weather systems in a changing climate. We presented findings to groups of researchers, broadcast and forecast meteorologists, and the general public over the life of the project. In addition to several publications, the model runs have been archived for public use by future researchers. The project trained one M.S. student, one post-doc, and two undergraduate researchers.
Last Modified: 07/15/2022
Modified by: Ankur R Desai
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