HAO 2010 PROFILES IN SCIENCE: Dr. Alan Burns
Contact
303-494-2178
aburns@ucar.edu
Dr. Alan Burns received his graduate degree from the University of Canterbury in Christchurch, New Zealand. His thesis involved middle atmosphere studies. He came to NCAR/HAO in 2000. Dr. Burns does research into the physics of the thermosphere and ionosphere with particular emphasis on neutral composition and geomagnetic storm effects. Current efforts are centered on CISM verification and development, producing a new capability to image the thermosphere in FUV (GOLD mission) and developing science from the COSMIC data.
Publications:
Burns, A.G., S.C. Solomon, W. Wang, G. Jee, C.H. Lin, C. Rocken, and Y.H. Kuo (2010), The Summer Evening Anomaly and conjugate effects, J. Geophys. Res., doi:10.1029/2010JA015648
(accepted 11 October 2010).
Abstract: The Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) GPS occultation data have been analyzed to provide a better understanding of Summer Evening Anomalies (SEA). There are distinct enhancements of the peak electron density NmF2 and increases in the height of this maximum hmF2 as soon as the conjugate footprint of the field line on the winter terminator is seen at middle latitudes in the summer hemisphere. This effect is most pronounced where the Weddell Sea Anomaly is formed, but it also occurs across the South Pacific Ocean in the southern summer, and across much of the North Atlantic Ocean, Siberia and Kamchatka during the northern summer. An hmF2 increase occurs between the two terminators even at locations where there is no increase in NmF2. A similar, but reversed, effect occurs in hmF2 near dawn. This behavior appears to be most consistent with upward and poleward ion drifts in the evening, but neutral wind and downward precipitation may make important contributions to this effect.
Figure caption: Global plots of NmF2 for two universal times: a) 0000 UT; b) 0500 UT. These plots are median plots of NmF2 for the periods from October 15–February 15 2006–2007 and 2007–2008. The color scale is saturated at 8 x105 /cc electrons. The hatched line represents the terminator, the dashed line the magnetic conjugate locations of the terminator in the other hemisphere (footprints of the flux tube running through the terminator in the opposite hemisphere) and the dotted line represents the magnetic equator.