Impact of geomagnetic excursions on atmospheric chemistry and dynamics ...

• Main Authors: Suter, I., Zech, Roland, Anet, J.G., Peter, Thomas
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2014
• Subjects: Antarc*; Antarctica; Geomagnetic Pole
• Online Access: https://dx.doi.org/10.3929/ethz-b-000087120; http://hdl.handle.net/20.500.11850/87120

Geomagnetic excursions, i.e. short periods in time with much weaker geomagnetic fields and substantial changes in the position of the geomagnetic pole, occurred repeatedly in the Earth's history, e.g. the Laschamp event about 41 kyr ago. Although the next such excursion is certain to come, little is known about the timing and possible consequences for the state of the atmosphere and the ecosystems. Here we use the global chemistry climate model SOCOL-MPIOM to simulate the effects of geomagnetic excursions on atmospheric ionization, chemistry and dynamics. Our simulations show significantly increased concentrations of nitrogen oxides (NOx) in the entire stratosphere, especially over Antarctica (+15%), due to enhanced ionization by galactic cosmic rays. Hydrogen oxides (HOx) are also produced in greater amounts (up to +40%) in the tropical and subtropical lower stratosphere, while their destruction by reactions with enhanced NOx prevails over the poles and in high altitudes (by −5%). Stratospheric ozone ... : Climate of the Past, 10 (3) ...