ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-11-6115-2011 Jet characterization in the upper troposphere/lower stratosphere (UTLS): applications to climatology and transport studies Manney G. L. 1 2 Hegglin M. I. 3 Daffer W. H. 1 Santee M. L. 1 Ray E. A. 4 5 Pawson S. 6 Schwartz M. J. 1 Boone C. D. 7 Froidevaux L. 1 Livesey N. J. 1 Read W. G. 1 Walker K. A. 3 7 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA New Mexico Institute of Mining and Technology, Socorro, NM, USA University of Toronto, Toronto, Ontario, Canada Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA Earth Systems Research Laboratory, NOAA, Boulder, CO, USA NASA/Goddard Space Flight Center, Greenbelt, MD, USA University of Waterloo, Waterloo, Ontario, Canada 29 06 2011 11 12 6115 6137 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/11/6115/2011/acp-11-6115-2011.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/6115/2011/acp-11-6115-2011.pdf

A method of classifying the upper tropospheric/lower stratospheric (UTLS) jets has been developed that allows satellite and aircraft trace gas data and meteorological fields to be efficiently mapped in a jet coordinate view. A detailed characterization of multiple tropopauses accompanies the jet characterization. Jet climatologies show the well-known high altitude subtropical and lower altitude polar jets in the upper troposphere, as well as a pattern of concentric polar and subtropical jets in the Southern Hemisphere, and shifts of the primary jet to high latitudes associated with blocking ridges in Northern Hemisphere winter. The jet-coordinate view segregates air masses differently than the commonly-used equivalent latitude (EqL) coordinate throughout the lowermost stratosphere and in the upper troposphere. Mapping O<sub>3</sub> data from the Aura Microwave Limb Sounder (MLS) satellite and the Winter Storms aircraft datasets in jet coordinates thus emphasizes different aspects of the circulation compared to an EqL-coordinate framework: the jet coordinate reorders the data geometrically, thus highlighting the strong PV, tropopause height and trace gas gradients across the subtropical jet, whereas EqL is a dynamical coordinate that may blur these spatial relationships but provides information on irreversible transport. The jet coordinate view identifies the concentration of stratospheric ozone well below the tropopause in the region poleward of and below the jet core, as well as other transport features associated with the upper tropospheric jets. Using the jet information in EqL coordinates allows us to study trace gas distributions in regions of weak versus strong jets, and demonstrates weaker transport barriers in regions with less jet influence. MLS and Atmospheric Chemistry Experiment-Fourier Transform Spectrometer trace gas fields for spring 2008 in jet coordinates show very strong, closely correlated, PV, tropopause height and trace gas gradients across the jet, and evidence of intrusions of stratospheric air below the tropopause below and poleward of the subtropical jet; these features are consistent between instruments and among multiple trace gases. Our characterization of the jets is facilitating studies that will improve our understanding of upper tropospheric trace gas evolution.

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