Stratospheric ozone variations caused by solar proton events between 1963 and 2005

Abstract

Some solar eruptions lead to solar proton events (SPEs) at the Earth, which typically last a few days. High energy solar protons associated with SPEs precipitate on the Earth’s atmosphere and cause increases in odd hydrogen (HOx) and odd nitrogen (NOy) in the polar cap regions (>60° geomagnetic). The enhanced HOx leads to short-lived ozone depletion (~days) due to the short lifetime of HOx constituents. The enhanced NOy leads to long-lived ozone changes because of the long lifetime of the NOy family in the stratosphere and lower mesosphere. Very large SPEs occurred in 1972, 1989, 2000, 2001, and 2003 and were predicted to cause maximum total ozone depletions of 1–3%, which lasted for several months to years past the events. A long-term data set of solar proton fluxes used in these computations has been compiled for the time period 1963–2005. Several satellites, including the NASA Interplanetary Monitoring Platforms (1963–1993) and the NOAA Geostationary Operational Environmental Satellites (1994–2005), have been used to compile this data set.