Cosmic Radiation Dose‐Rates for Civil Aviation in the Middle East: Vertical Structure, Solar Modulation, and Comparison With Models

Abstract

Abstract High‐altitude balloon measurements were conducted over southern Israel (30°35′N, 34°45′E; 850 m a.s.l., geomagnetic rigidity cutoff 10.3 GV) to characterize the vertical profiles of atmospheric ionization and radiation up to ∼35 km. Six balloon launches between October 2014 and August 2016 recorded the variability of atmospheric ionization during the declining phase of Solar Cycle 24. The Regener–Pfotzer maximum was observed at ∼17–20 km, consistent with mid‐latitude conditions. The gamma‐equivalent dose‐rate proxy, derived from calibrated Geiger–Müller tube measurements, increased with altitude to a maximum near the Regener–Pfotzer altitudes and decreased sharply above it. At civil aviation altitudes (∼10 km), the measured dose rates were in the range ∼0.9–1.3 μSv hr −1 and exhibited an inverse relationship with solar activity ( r = −0.71). A strong linear dependence on heliospheric modulation potential was observed, with extrapolated values indicating a 40%–60% increase in dose rates under solar minimum conditions. Comparison with the EXPACS/PARMA atmospheric radiation model shows that the measurements closely match the electromagnetic component (photons and electrons/positrons) of the radiation field, typically within ∼10%–15%, while the total ambient dose equivalent H*(10) was dominated by neutrons. These results demonstrate that balloon‐borne measurements can provide a robust characterization of the vertical radiation structure and its solar modulation, while highlighting the distinction between electromagnetic dose proxies and total radiation exposure.