Space Weather Nowcast of Atmospheric Ionizing Radiation for Aviation Safety NAIRAS Team –Chris Mertens (PI) –Kent Tobiska (Co-I), Space Environment Technologies, Inc, Pacific Palisades, CA. –Brian Kress (Co-I), Dartmouth College, Hanover, NH. –Stan Solomon (Co-I), NCAR/HAO, Boulder, CO. –Mike Wiltberger (Co-I), NCAR/HAO, CO. –Joe Kunches (Collaborator), NOAA/Space Environment Center, Boulder, CO. –Barbara Grajewski (Collaborator), CDC/NIOSH, Cincinnati, OH –Steve Blattnig, (Collaborator), LaRC RT/Space Radiation Group –John Norbury (Collaborator), LaRC RT/Space Radiation Group –Tony Slaba (Collaborator), LaRC RT/Space Radiation Group NASA Applied Science Weather Program Review Boulder, Colorado, November 19, 2008

Outline Project Overview Summary of Milestones Discussion of Milestones Publications Summary

Earth System Models Radiation Dose Rates: AIR (parametric) HZETRN (physics-based) Near-Earth Space Environment Badhwar/O’Neill GCR Model Empirical Cutoff Rigidity ( IGRF+T05) Physics-based Cutoff Rigidity (LFM/CMIT+SEP-trajectory) Earth System Models Radiation Dose Rates: AIR (parametric) HZETRN (physics-based) Near-Earth Space Environment Badhwar/O’Neill GCR Model Empirical Cutoff Rigidity ( IGRF+T05) Physics-based Cutoff Rigidity (LFM/CMIT+SEP-trajectory) Value & Benefits to Society Improvements in the decision- making, decisions, and actions First-ever, data-driven, real-time prediction of biologically harmful radiation exposure levels at commercial airline altitudes Quantitative and qualitative benefits from the improved decisions Comprehensive database of radiation dose rates to formulate recommended annual and career limits to ionizing radiation exposure Comprehensive database of radiation dose rates for airlines to assess cost/risk of polar routes Real-time prediction of radiation exposure levels to enable optimal balance between airline cost and air traveler health risk during solar storm (SEP) events Improve understanding of biological effects of atmospheric ionizing radiation on aircrew and passengers through collaboration of epidemiological studies by NIOSH Value & Benefits to Society Improvements in the decision- making, decisions, and actions First-ever, data-driven, real-time prediction of biologically harmful radiation exposure levels at commercial airline altitudes Quantitative and qualitative benefits from the improved decisions Comprehensive database of radiation dose rates to formulate recommended annual and career limits to ionizing radiation exposure Comprehensive database of radiation dose rates for airlines to assess cost/risk of polar routes Real-time prediction of radiation exposure levels to enable optimal balance between airline cost and air traveler health risk during solar storm (SEP) events Improve understanding of biological effects of atmospheric ionizing radiation on aircrew and passengers through collaboration of epidemiological studies by NIOSH Predictions/Forecasts Observations, Parameters & Products Earth Observations Near-Earth Space Environment NASA/ACE NASA/HEAO-3 NOAA/GOES Assimilated Atmospheric Atmospheric Depth (NCAR/NCEP) Ground-Based Neutron Count Monitors Earth Observations Near-Earth Space Environment NASA/ACE NASA/HEAO-3 NOAA/GOES Assimilated Atmospheric Atmospheric Depth (NCAR/NCEP) Ground-Based Neutron Count Monitors Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) Ionizing Radiation Nowcast 3-D Dose Equivalent 3-D Differential Flux NAIRAS Distributed Network System High-Performance Computer Systems Server Interface Operational and Archival Databases Differential Particle Flux HZE Particles (Z=5-26) Light-Ions (Z=1-4) Neutrons Pions and Muons Electromagnetic Cascasde Particles Ionizing Radiation Nowcast 3-D Dose Equivalent 3-D Differential Flux NAIRAS Distributed Network System High-Performance Computer Systems Server Interface Operational and Archival Databases Differential Particle Flux HZE Particles (Z=5-26) Light-Ions (Z=1-4) Neutrons Pions and Muons Electromagnetic Cascasde Particles Decision Support Systems, Assessments, Management Actions NAIRAS decision support tool for NOAA/SEC space weather forecasts, warnings, and advisories NAIRAS available at NOAA/ADD experimental aviation-related weather forecasts, observations, and analysis Specific analyses to support the decision making Predict real-time radiation exposure at commercial airline altitudes (includes background GCR and SEP events) Provide accumulated radiation exposures for representative set of domestic, international, and polar routes Specific Decisions / Actions Limit aircrew flight hours to within recommended annual and career limits Alter route and/or altitude during SEP events Decision Support Systems, Assessments, Management Actions NAIRAS decision support tool for NOAA/SEC space weather forecasts, warnings, and advisories NAIRAS available at NOAA/ADD experimental aviation-related weather forecasts, observations, and analysis Specific analyses to support the decision making Predict real-time radiation exposure at commercial airline altitudes (includes background GCR and SEP events) Provide accumulated radiation exposures for representative set of domestic, international, and polar routes Specific Decisions / Actions Limit aircrew flight hours to within recommended annual and career limits Alter route and/or altitude during SEP events

Real-time Neutron Monitor Data (e.g., IZMIRAN and LOMICKY) Physics-Based Atmospheric Ionizing Radiation Dosimetry HZETRN + Dosimetry Fit to Climax NMC Badhwar+O’Neill GCR Model NOAA GOES Data Spectral Fitting Magnetospheric Magnetic Field (e.g., T05) Effects on Cutoff Rigidity Cutoff Rigidity (IGRF) Atmospheric Density NCAR/NCEP Reanalysis Atmospheric Dose and Dose Equivalent NASA/ACE Solar Wind and IMF Data

Important Milestones Achieved(1) NAIRAS operational distributed network system –System designed and implementation underway –Model I/O requirements and sources defined –Redundancy established for all input data products Operational HZETRN –Automated canonical radiation flux and dose rate calculations performed on 2-D (rigidity, atmospheric depth) grid –Preliminary coupling to SEP fluence spectral fit model, cutoff rigidity model, and NCAR/NCEP Reanalysis Data (air temperature and geopotential height) –Working on including directional anisotropy in rigidity, flux, and subsequent dose predictions Directionally-coupled low-energy neutron transport –Tony Slaba’s PhD thesis and post-doc work (ODU) –Validated against Monte Carlo Codes (FLUKA and HET-HEADS) for September 1989 SEP event –Now Implemented in NAIRAS –Factor 4 greater doses rates in polar cap region

Important Milestones Achieved(2) SEP proton and alpha fluence spectral fitting to ACE/GOES –Version 1 operational algorithm implemented with preliminary testing –Funded two students through the Langley Aerospace Research Summer Scholars (LARSS) Program to contribute to this work Analysis of Halloween 2003 SEP events –Storm-time geomagnetic effects on cutoff rigidities critical  Magnetospheric effects reduce mid- to high-latitude cutoffs by as much as a 1 GV.  Increase total dose by as much as a factor of 4 –ICRP prenatal exposure exceeded during typical commercial polar routes

NAIRAS Operational Distributed Network System Next Slide

NAIRAS Operational Distributed Network System

NAIRAS Models and I/O Definitions Next Two Slides

SEP Proton and Alpha Fluence Spectral Fitting Next Five Slides

SEP Event 3 From Previous Slide Event-Averaged Analysis for Event 3 in Next Section

HZETRN SEP Atmospheric Transport Incident SEP spectra: non-linear least-squares spectral fit to NOAA/GOES and NASA/ACE Double power-law spectrum [Mewaldt, 2003]

Analysis of Halloween 2003 SEP Event Next Six Slides

High-latitude routes can exceed ICRP prenatal limit (1 mSv) ICRP annual limit (20 mSv)

Flight Path Dose Eq. T05S (mSv) Dose Eq. T05Q (mSv) Dose Eq. IGRF (mSv) Dose Ratio T05S/IGRF Dose Ratio T05S/T05Q Dose Ratio T05Q/IGRF JFK-LHR ORD-ARN ORD-PEK Summary of Total Dose Equivalent and Influence of Geomagnetic Effects T05S: Tsyganenko (T05) Storm Field T05Q: Tsyganenko (T05) Quiet Field ICRP prenatal limit (1 mSv) exceeded Neglect geomag effects underestimates dose by factor 4 IGRF underestimates geomag quiet condition by ~ 40%

Publications Journal of Space Weather (January, 2009) – Geomagnetic effects on high-latitude radiation exposure during a Halloween 2003 solar energetic particleevent (Mertens et al.) Journal of Space Weather (January 2009) –Variations in geomagnetic shielding of energetic solar ions during severe geomagnetic storms (Kress et al.) AIAA Paper ( AIAA , January, 2008 ) –Influence of space weather aircraft ionizing radiation exposure (Mertens et al.)

Summary Operational distributed network system development on schedule Operational HZETRN development on schedule Directionally-coupled, low-energy neutron transport with coupling to light-ion transport implemented and tested in NAIRAS. SEP proton and alpha fluence spectral fitting model developed. Initial testing in progress. Atmospheric radiation exposure during Halloween 2003 SEP event exceeded ICRP prenatal exposure limit (1 mSv) for typical polar route. Some high-latitude routes reached ~ 85% of ICRP prenatal limit. Neglecting time-dependent geomagnetic storm influences on cutoff rigidity during SEP events significantly underestimates radiation dose from ~ 30% to over a factor of 4 IGRF field can result in underestimation of high-latitude radiation dose by ~40% for SEP events without accompanying geomagnetic storm Two peer-reviewed journal articles in progress. One AIAA paper published.