LIMS (Limb Infrared Monitor of the Stratosphere) observation of traveling planetary waves and potential vorticity advection in the stratosphere and mesosphere

Journal Article · Wed Feb 20 04:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JD02340· OSTI ID:5560823

Dunkerton, T J ^[1]

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1. Northwest Research Associates, Inc., Bellevue, WA (USA)

Eastward and westward traveling waves were observed by the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) during the northern winter 1978-1979. Eastward waves were prevalent in early winter and were involved in a minor Canadian warming in December 1978. A large westward traveling wave, as described by previous authors, was observed in January 1979 during a series of minor warmings. By comparing these two events, it is shown that in both cases the superposition of traveling and quasi-stationary waves led to constructive interference that was responsible for the warmings. However, there was significant asymmetry between eastward and westward traveling components. Eastward disturbances were confined mostly within the polar vortex, whereas quasi-stationary and westward traveling components propagated to the vortex periphery and beyond, into the tropics and mid-latitude mesosphere. This behavior is consistent with Rossby wave propagation and indicates that the location and magnitude of planetary wave breaking is sensitive to the frequency spectrum entering the middle atmosphere. However, this asymmetry is also a signature of the nonlinear critical layer as it projects onto the frequency spectrum. Both interpretations are shown to be valid during wave events observed by LIMS. A local Eulerian analysis of potential vorticity (PV) transport indicates that adiabatic, geostrophic advection by the resolvable scales of motion explains qualitatively (but not quantitatively) the observed potential vorticity tendencies in the LIMS northern hemisphere winter. In particular, calculated advection explains the eastward rotation of the main vortex, intrusion of low PV air into the polar cap, and formation of high PV filaments at the vortex periphery.

• OSTI ID: 5560823
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:D2; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ADVECTION
CANADA
DEVELOPED COUNTRIES
EARTH ATMOSPHERE
EARTH PLANET
ELECTROMAGNETIC RADIATION
INFRARED RADIATION
MASS TRANSFER
MESOSPHERE
NORTH AMERICA
NORTHERN HEMISPHERE
PLANETS
POLAR REGIONS
RADIATIONS
STRATOSPHERE
TRAVELLING WAVES
VORTICES
WAVE PROPAGATION