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EOS Microwave Limb Sounder observations of “frozen‐in” anticyclonic air in Arctic summer
Author(s) -
Manney G. L.,
Livesey N. J.,
Jimenez C. J.,
Pumphrey H. C.,
Santee M. L.,
MacKenzie I. A.,
Waters J. W.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl025418
Subject(s) - anticyclone , microwave limb sounder , geology , climatology , atmospheric sciences , latitude , arctic , stratosphere , oceanography , geodesy
A previously unreported phenomenon, a “frozen‐in” anticyclone (FrIAC) after the 2005 Arctic spring vortex breakup, was discovered in Earth Observing System (EOS) Microwave Limb Sounder (MLS) long‐lived trace gas data. A tongue of low‐latitude (high‐N 2 O, low‐H 2 O) air was drawn into high latitudes and confined in a tight anticyclone, then advected intact in the summer easterlies through late August. A similar feature in O 3 disappeared by early April as a result of chemical processes. The FrIAC was initially advected upright at nearly the same speed at all levels from ∼660 to 1300 K (∼25–45 km); increasing vertical wind shear after early June tilted the FrIAC and weakened it at higher levels. The associated feature in PV disappeared by early June; transport calculations fail to reproduce the remarkable persistence of the FrIAC, suggesting deficiencies in summer high‐latitude winds. The historical PV record suggests that this phenomenon may have occurred several times before. The lack of a persistent signature in O 3 or PV, along with its small size and rapid motion, make it unlikely that a FrIAC could have been reliably identified without hemispheric daily long‐lived trace gas profiles such as those from EOS MLS.