Characterising space radiation and its impact on climate change
Large geomagnetic space storms, whose occurrence and intensity follows the 11-year solar cycle, increase the radiation trapped in near-Earth space in the Van Allen belts by several orders of magnitude over timescales of hours to days, weeks and months. This radiation is lost from the Van Allen belts via precipitation into the atmosphere, creating additional ionization as these particles, of energies of ~100 keV to several MeV, impact the atmosphere at altitudes of ~50-80 km. Recent research has shown that the ionization resulting from the precipitation of this space radiation is a significant source of NO (from the dissociation of molecular nitrogen) in the upper stratosphere, and that this NOx chemistry causes significant ozone depletion. The changes in ozone concentration affect the thermal balance, and the atmospheric chemistry, and ultimately can result in climatic change in the lower atmosphere.
State of the art global climate models do not currently include these space radiation effects although recent observational studies (e.g., Randall et al., GRL, 2005) have verified that the ozone and hence potentially climatic effects could be important. This proposal will provide timely seed funding to kick-start a new and innovative interdisciplinary research collaboration that will determine the impact of space radiation on atmospheric chemistry and climate. This will be achieved through the hosting of a Workshop, to be held following but contiguous with an upcoming international Chapman Conference “The Dynamics of the Earth’s Radiation Belts and Inner Magnetosphere” to be held in Canada in July 2011. The Chapman Conference will provide an efficient mechanism for the partners to understand the international state-of-the-art in Earth space radiation.
In the follow-on 2-day WUN RDF workshop, a Collaboration Plan defining the steps the team will take to quantify the impact of solar driven space radiation on upper stratospheric NOx and ozone chemistry, and hence their role in climate change, will be developed and then implemented.