Share icon
We propose to develop a prototype Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model. The NAIRAS model combines observations of Earth's near-space and atmospheric variables with radiation environment and transport models to provide science results to decision support systems in the aviation area of national priority. The NAIRAS model will provide the first-ever, global, real-time, data-driven, atmospheric ionizing radiation dosimetry package for archiving and assessing biologically harmful radiation exposure levels at commercial airline altitudes. The source of biologically harmful (i.e., ionizing) atmospheric radiation is galactic cosmic rays (GCR), and the solar energetic particle events (SEP) that can accompany disturbances on the Sun's surface. The sources, composition, and energy-spectra of atmospheric ionizing radiation are subject to sources and variability of space weather phenomena. As a result, the NAIRAS model directly responds to the priority to provide space weather decision support tools related to radiation impacts on crew and passengers of long-range aircraft, as specified in this year's DECISIONS solicitation for the aviation national area of priority. The NAIRAS model will enhance the performance of the decision support tools provided by the NOAA Space Environment Center (SEC), since this decision support system currently does not monitor or estimate the ionizing radiation present in the atmosphere at commercial airline altitudes. The end-user communities that will benefit from the NAIRAS model are the commercial airline industry (airline corporations and aircrew professional associations), the FAA, NIOSH, and NOAA/SEC. Results from the NAIRAS model will provide a tool for its end-user organizations to develop policy and procedures for mitigating biologically harmful radiation exposure and aircrew career planning - especially during SEP events. NAIRAS results will also aid in the formulation of recommended aircrew annual and career radiation dose limits, and will enhance epidemiological studies conducted to better understand the biological effects of atmospheric ionizing radiation on passengers and aircrew. Observations are utilized from the ground (neutron monitors), from the atmosphere (the METO analysis), and from space (NASA/ACE and NOAA/GOES). Dose rates are simulated using the AIR (Atmospheric Ionizing Radiation) model, which is a validated parametric model, and the HZETRN (High Charge and Energy Transport) model, which is a state-of-the-art, physics-based galactic cosmic ray (GCR) and SEP radiation transport code. The physics-based CMIT (Coupled Magnetosphere-Ionosphere-Thermosphere) and SEP-trajectory models are employed to benchmark the magnetosphere-ionosphere-thermosphere response to GCR and SEP events to facilitate the transition of research space radiation environment models to real-time operational usage.