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CATEGORIES:British Antarctic Survey
SUMMARY:Tropical fingerprints on the polar mesosphere - Dr
  R E Hibbins\, British Antarctic Survey
DTSTART;TZID=Europe/London:20071121T140000
DTEND;TZID=Europe/London:20071121T150000
UID:TALK9235AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/9235
DESCRIPTION:An analysis of 11 years of horizontal wind data de
 rived from meteor wind observations from a SuperDA
 RN radar at Halley\, Antarctica shows clear eviden
 ce of a quasi-biennial modulation of the high lati
 tude southern hemisphere semidiurnal tide in the u
 pper mesosphere. The tide is enhanced when the equ
 atorial stratospheric QBO above 10 hPa is in the w
 esterly phase. This enhancement is greatest in the
  summer time when the S=1 non-migrating component 
 is known to dominate the semidiurnal wind field at
  high latitudes\, and is coincident with an enhanc
 ement of the summertime planetary wave activity in
  the upper mesosphere. These results strongly supp
 ort the hypothesis that the S=1 component of the s
 emidiurnal tide observed at high latitudes is due 
 to a non-linear interaction between the migrating 
 S=2 semidiurnal tide and quasi-stationary S=1 plan
 etary waves\, the propogation of which is dependen
 t on the critical level filtering driven by the eq
 uatorial QBO.\n
LOCATION:British Antarctic Survey\, Room 330B
CONTACT:Tracy Moffat-Griffin
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