FAQ
    
    AGREEMENT STATES
    
    Facility Locator
    
    What's New
    
    Site Help
    
    Index A-Z
    
    Contact Us
    
    Email Updates
      
      
      
      
       
      Report a Safety Concern
                  Search
        Nuclear Reactors
  
  Power Reactors
Research & Test ReactorsOperating Reactors
New ReactorsOperator Licensing
Research ActivitiesNuclear Reactor Quick LinksNuclear Materials
  
  Types of Nuclear Materials
Fuel Cycle Facilities
Medical, Industrial, & Academic UsesUranium Recovery
Materials TransportationMaterials Environmental Reviews
National Materials ProgramNuclear Materials Quick LinksRadioactive Waste
  
  Decommissioning of Nuclear Facilities
Low-Level Waste
Waste Incidental to Reprocessing
High-Level WasteUranium Mill Tailings
Low-Level Waste Disposal
High-Level Waste DisposalStorage of Spent Nuclear Fuel
Transportation of Spent Nuclear Fuel
Research ActivitiesRadioactive Waste Quick LinksNuclear Security
  
  Domestic Safeguards
Information Security
Radioactive Material SecurityRequired Reporting for Clearance Holders
Insider Threat Program for Licensees
CybersecurityCriminal History & Firearms Checks
Contact UsPublic Meetings & Involvement
  
  The NRC Approach to Open Government
About Meetings Open to the Public
Conferences & SymposiaDocuments for Comment
NRC Rules and Petitions
Facilitating Stakeholder InvolvementNRC Information Quality Guidelines
Subscribe to E-mail UpdatesCommission Schedule
Public Meeting ScheduleAdjudications (Hearings)
Adjudicatory SubmissionsNRC Library
  
  Basic References
Document Collections
ADAMS Public Documents
Public Document Room
LSN LibraryFOIA & Privacy Act
Photos & Videos
Records Management
Training CoursesFAQ Index
Get Copies of Documents
Withholding of Sensitive Information
Controlled Unclassified Information Program (CUI)Electronic Hearing DocketAbout NRC
  
  The Commission
Organization & Functions
Governing Legislation
Plans, Budget, & Performance
Locations
History
Values
Direction-Setting & Policymaking
Research Activities
Radiation ProtectionFire Protection
Safety Culture
How We Regulate
Emergency Preparedness & Response
Public Affairs
Congressional Affairs
Enforcement
International Programs
State & Tribal ProgramsAlternative Dispute Resolution Programs
Privacy Program
Civil Rights Program
Contact Us
Career Opportunities
Contracting Opportunities
Small Businesses
Grant Opportunities
Generic SchedulesOther Links
  
  FAQ
Glossary
Facility Locator
What's NewSite Help
Index A-Z
Contact Us
Email UpdatesNRC Facebook
NRC Twitter Feed
NRC Linkedin
NRC Youtube Channel
NRC Flickr Gallery
NRC Blog Archived
NRC Email Subscriptions - GovDelivery Home
          NRC Library  Document Collections  NUREG-Series Publications  Publications Prepared by NRC ContractorsConvection-Permitting Modeling for Intense Precipitation Processes (NUREG/CR-7290)

On this page:

Publication Information
	AbstractDownload complete document

NUREG/CR-7290 (PDF – 7.11 MB)Publication Information

**Manuscript Completed:** September 2021**Date Published:** May 2023

**Prepared by:**
Andreas F. Prein
Jordan G. Powers
Erin L. Towler
David Ahijevych
Ryan A. Sobash
Craig S. Schwartz

National Center of Atmospheric Research (NCAR)
3090 Center Green Dr.
Boulder, CO 80301

Elena Yegorova, NRC Project Manager
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington DC 20555-0001

Availability Notice

Abstract

This report documents work sponsored by the U.S. Nuclear Regulatory Commission (NRC) and conducted by the National Center for Atmospheric Research (NCAR) as part of the RES project, "Convection-Permitting Modeling for Intense Precipitation Processes." This project was undertaken as part of the Probabilistic Flood Hazard Assessment (PFHA) Research Program. The objective of the PFHA Research Program is to develop tools and guidance on the use of PFHA methods to risk-inform NRC's licensing of new facilities as well as the licensing and oversight of currently operating facilities as they relate to flooding hazards.

Many flooding scenarios of interest to nuclear power plant (NPP) licensing and oversight involve extreme precipitation events occurring at the plant site or within the watershed of the plant. Generating probabilistic assessments of extreme precipitation within a catchment is challenging due to typically short observational records, insufficient data coverage, and climatic variation. Furthermore, traditionally used estimators of extreme precipitation, such as Probable Maximum Precipitation (PMP), do not allow for the quantification of uncertainties in hazard estimates in either a physical or a risk sense. The application of numerical atmospheric models to the problem offers a way forward. State-of-the-art convection-permitting models (CPMs) can explicitly simulate deep convection and can accurately represent orography on fine scales, and thus they present powerful tools for investigating extreme precipitation events. Using convection-permitting models is, therefore, a valuable alternative approach in the provision of more physically-based and probabilistic flood risk assessments.

This report includes a thorough literature review and analysis that summarize the state of the science in simulating extreme precipitation events with convection-permitting models while outlining key challenges, opportunities, and promising research areas. Based on the literature review, we assess the ability of CPMs to capture extreme precipitation in recent flood events in the contiguous U.S. (CONUS) east of the Rocky Mountains by leveraging three existing convection-permitting ensemble datasets. These cover 10,570 36-hour simulations/forecasts at 3-km horizontal grid spacing (Δx=3 km) and 810 36-hour simulations at Δx=1 km spacing. Additionally, we analyze the impact of observational uncertainties on the results by using a selection of high-quality multi-sensor and gauge-based rainfall datasets.

The central finding is that numerical weather prediction models configured with convection permitting resolutions can capture heavy precipitation events in the Eastern U.S. Many aspects of the simulations are verified by multi-sensor observational datasets, and the precipitation output from the convection-permitting (CP) model configurations shows less error than precipitation estimates based on station data. This demonstrates the potential value of incorporating CP model outputs in flood risk assessments. However, CP model configurations are not perfect and sometimes show systematic biases, as revealed in case examples of the underestimation of event peak accumulations by up to 30%. While one way to reduce these biases is by statistical post-processing, over the long-term model development to improve fidelity is the preferred way to address the issue.

The report closes with two recommendations for future work on the usage of CPM output for probabilistic flood risk assessments. First, targeted downscaling of heavy precipitation events in global climate models with CPMs would allow the building of a catalog of heavy precipitation events that are physically plausible, but unprecedented in the observational record. Second, events from this catalog and existing CPM heavy precipitation simulations could be used in combination with statistical approaches, such as stochastic storm transposition, to generate a large set of plausible heavy rainfall events to generate input for hydrologic models (e.g., WRF-Hydro).

      
      Page Last Reviewed/Updated Wednesday, May 03, 2023  Home
NEWS RELEASES

EVENT REPORTS

ADAMS

OPEN GOV

DIGITAL GOVERNMENT

THE STUDENT CORNER

PHOTOS & VIDEOS

FOR DEVELOPERS
        About Us
STRATEGIC PLAN

BUDGET & PERFORMANCE

AGENCY FINANCIAL REPORT

LICENSE FEES

HISTORY OF THE NRC

CAREER OPPORTUNITIES

NRC ETHICS

AGENCY STATUS

CONTACT US
        Popular Documents
INFO DIGEST

FACT SHEETS & BROCHURES

FORMS

ELECTRONIC SUBMITTALS APPLICATION

ADJUDICATORY SUBMISSIONS

NRC REPORTS - NUREG

NRC REGULATIONS - 10-CFR

INSPECTION REPORTS

PLAIN WRITING

ENFORCEMENT ACTIONS

RULEMAKING

GLOSSARY
        Stay Connected
    
    
    
    
    United States Nuclear Regulatory Commission
    
    
    
    
    Regulations.gov

USA.gov

FOIA

Whistleblower Protection

No Fear EEO

Inspector General

Site Map

Accessibility

Privacy Policy

Site Disclaimer

For Employees