| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
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| Initial Amendment Date: | October 22, 2020 |
| Latest Amendment Date: | October 22, 2020 |
| Award Number: | 2054706 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Chungu Lu
AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | November 1, 2020 |
| End Date: | October 31, 2021 (Estimated) |
| Total Intended Award Amount: | $21,976.00 |
| Total Awarded Amount to Date: | $21,976.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
506 S WRIGHT ST URBANA IL US 61801-3620 (217)333-2187 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
506 S. Wright Street Urbana IL US 61801-3620 |
| 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): | Physical & Dynamic Meteorology |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
On 10 August 2020, a particularly intense derecho produced widespread high-wind damage from eastern Nebraska through northern Indiana, resulting in 3.8 billion USD in estimated agricultural losses in Iowa. Derechos, or long-lived windstorms produced by mesoscale convective systems (MCSs), remain an important atmospheric phenomenon to understand because they produce large-scale wind damage areas, varying from 20 ? 200 km in width to hundreds of kilometers long. This award will allow a multidisciplinary scientific team (i.e., atmospheric scientists, remote sensing experts, wind and structural engineers) to perform high-resolution numerical simulations and detailed damage surveys across multiple spatial scales to investigate storm processes in derechos. Relating detailed documentation of high-wind damage with storm processes can provide vital information on extreme wind production in derechos and storm damage potential, leading to improved understanding of severe-storm processes, radar interpretation, and risk communication associated with warnings to the general public.
Storm characteristics and near-surface wind flow of 10 August 2020 derecho will be investigated through 1) high-resolution simulations of the event using a state-of-the-art numerical modeling system as a proxy for the real event, and 2) detailed comparisons of radar signatures to damage information provided by 2D and 3D analyses of unpiloted aerial systems (UAS) data, satellite imagery, and ground truth surveys. Simulations that best depict the evolution of the derecho will be analyzed to explore the mechanisms responsible for the unique physical characteristics of this event that were responsible for the extreme wind production. The large-scale character of the damaging winds over vegetation and crops susceptible to long-term damage and passage of the derecho?s core close to Des Moines and Davenport National Weather Service radars in Iowa provide a unique opportunity to better connect damage information to velocity structures sampled by radar. The detailed analysis of wind damage produced in this study will provide an unprecedented validation dataset for the high-resolution numerical simulations. This unusually comprehensive dataset will be used to understand the physical processes responsible for extreme wind damage. Additionally, detailed damage documentation can also be used to calibrate satellite-based assessments in future high-wind events and could enable the development of additional damage descriptors based to vegetation.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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.
The derecho event of 10 August 2020 is considered the most costly thunderstorm event in the US History. As a large proportion of the losses were in rural and agricultural areas measurements of near-surface wind speeds were very sparse. This sparsity, coupled with the fact that "official" observing stations lost power during the event necessitated a rapid and detailed investigation of the damage left in the wake of the event.
A major objective of this RAPID project was the multi-scale characterization of damage produced by the derecho to refine near-surface wind speed estimates in both rural and built environments. The PI traveled to the area two times following the event to collected aerial and ground-based imagery, along with damage data to the perform these near-surface wind speed estimations. Once the data was collected, near-surface wind speed estimation was carried out through any and all available methods which included pattenrs of corn-fall, sign damage analysis and existing anemometry. Wind speed estimates were generated through the use of analytical and physical modeling.
Two major findings were discovered as a result of the research. The first finding was that for an event of this type with very large swaths of high wind speeds (compared to building scales) that exposure appears to have played a significant role in wind speeds and subsequent damage levels. Highly exposed structures (e.g., open terrain, multiple stories) with long-axis perpendicular to the wind suffered the most damage while tighly packed single story structures in the same general area suffered little or no damage.
The second finding was that the estimated wind speed in standard conditions (open terrain, 10 m) were approximately 115-120 mph in the Cedar Rapids area -- corresponding closely to a 1700 yr. event, which is at or above a "design wind event" for most structure types. Future research will aim at better classifying these wind events in empirical and probabilistic models to better estimate their occurrence and better understand overall derecho risk for buildings and other structures. Images relating to this research are provided within this report.
Last Modified: 03/03/2022
Modified by: Franklin Lombardo
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