Title The 16-day wave in the Arctic and Antarctic mesosphere and lower thermosphere
Author Day, K.A.; Mitchell, N.J.
Author Affil Day, K.A., University of Bath, Centre for Space, Atmospheric and Oceanic Science, Bath, United Kingdom
Source Atmospheric Chemistry and Physics, 10(3), p.1461-1472. Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1680- 7316
Publication Date 2010
Notes In English. Published in Atmospheric Chemistry and Physics Discussions: 25 November 2009, http://www.atmos-chem-phys- discuss.net/9/25213/2009/acpd-9-25213-2009.ht ml; accessed in May, 2011. 39 refs. GeoRef Acc. No: 310099. CRREL Acc. No: 65006754
Index Terms climate; radar; remote sensing; statistical analysis; temperature; Arctic region; Sweden--Esrange; Sweden--Kiruna; Antarctica--Rothera; angular momentum; Antarctica; atmosphere; energy; Esrange Sweden; Europe; Kiruna Sweden; mesosphere; Norrbotten Sweden; radar methods; Rossby waves; Rothera Antarctica; satellite methods; Scandinavia; seasonal variations; Sweden; thermosphere; time series analysis; Western Europe; winds
Abstract The 16-day planetary wave in the polar mesosphere and lower thermosphere has been investigated using meteor radars at Esrange (68N, 21E) in the Arctic and Rothera (68S, 68W) in the Antarctic. The measurements span the 10-year interval from October 1999 to July 2009 and the 5-year interval February 2005 to July 2009, respectively. The height range covered is about 80-100 km. In both polar regions the wave is seen to occur in intermittent bursts, where wave amplitudes typically reach a maximum of about 15 m s-1, and never more than about 20 m s-1. Horizontal wind variance within a wave-period range of 12 to 20 days is used as a proxy for the activity of the 16-day wave. Wave activity is strong for 3 to 4 months in winter, where it is present across the entire height range observed and monthly wave variance reaches about 65 m2 s-2. Some weak and intermittent activity is observed throughout the other seasons including summer. However, there is a high degree of inter-annual variability and in some individual years wave activity is almost absent. The data are used to construct a representative climatology for the Arctic and Antarctic. The seasonal cycle of the 16-day wave is found to be very similar in both polar regions. The 16-day wave has slightly greater amplitudes in the zonal component of the winds than in the meridional. Mesospheric temperatures measured by the radars were used to further investigate the 16-day wave. The temperatures reveal a clear signature of the 16-day wave. Temperature amplitudes are generally only a few Kelvin but occasional bursts of up to 10 K have been observed. Observations of the wave in summer are sometimes consistent with the suggestion of ducting from the winter hemisphere.
URL http://www.atmos-chem-phys.net/10/1461/2010/acp-10-1461-2010.pdf
Publication Type journal article
Record ID 91459