Nightglow on Venus

Noting that nightglow emissions are important tracers of upper atmospheric transport, Gйrard et al. study Venus’s nightglow using data from the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board the European Space Agency’s Venus Express spacecraft. Past research has shown that solar ultraviolet light splits CO2 molecules on Venus’s dayside, releasing oxygen atoms; these atoms are transported to the nightside where they combine to form oxygen molecules, releasing energy and producing nightglow. Through VIRTIS images, the authors characterize the distribution of excited oxygen molecules over most of the southern hemisphere and find that the nightglow observed requires that approximately 50 percent of the oxygen atoms produced in the dayside be carried to the nightside by global circulation. This requirement will be important to refine circulation models of Venus’s atmosphere.-American Geophysical Union