Transport in the subtropical lowermost stratosphere during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers

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Read Full Article (file size: 9723420 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, D08304, doi:10.1029/2006JD007851, 2007 Transport in the subtropical lowermost stratosphere during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers–Florida Area Cirrus Experiment Jasna V. Pittman Departments of Earth and Planetary Sciences and of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA Elliot M. Weinstock Departments of Earth and Planetary Sciences and of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA Robert J. Oglesby Department of Geosciences, University of Nebraska, Lincoln, Nebraska, USA David S. Sayres Departments of Earth and Planetary Sciences and of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA Jessica B. Smith Departments of Earth and Planetary Sciences and of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA James G. Anderson Departments of Earth and Planetary Sciences and of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA Owen R. Cooper Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA Steven C. Wofsy Departments of Earth and Planetary Sciences and of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA Irene Xueref Departments of Earth and Planetary Sciences and of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA Cristoph Gerbig Departments of Earth and Planetary Sciences and of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA Bruce C. Daube Departments of Earth and Planetary Sciences and of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA Erik C. Richard Earth System Research Laboratory, NOAA, Boulder, Colorado, USA Brian A. Ridley Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado, USA Andrew J. Weinheimer Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado, USA Max Loewenstein NASA Ames Research Center, Moffett Field, California, USA Hans-Jurg Jost Bay Area Environmental Research Institute, Sonoma, California, USA Jimena P. Lopez Bay Area Environmental Research Institute, Sonoma, California, USA Michael J. Mahoney Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA Thomas L. Thompson Earth System Research Laboratory, NOAA, Boulder, Colorado, USA William W. Hargrove Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA Forrest M. Hoffman Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA Abstract We use in situ measurements of water vapor (H₂O), ozone (O₃), carbon dioxide (CO₂), carbon monoxide (CO), nitric oxide (NO), and total reactive nitrogen (NO_y) obtained during the CRYSTAL-FACE campaign in July 2002 to study summertime transport in the subtropical lowermost stratosphere. We use an objective methodology to distinguish the latitudinal origin of the sampled air masses despite the influence of convection, and we calculate backward trajectories to elucidate their recent geographical history. The methodology consists of exploring the statistical behavior of the data by performing multivariate clustering and agglomerative hierarchical clustering calculations and projecting cluster groups onto principal component space to identify air masses of like composition and hence presumed origin. The statistically derived cluster groups are then examined in physical space using tracer-tracer correlation plots. Interpretation of the principal component analysis suggests that the variability in the data is accounted for primarily by the mean age of air in the stratosphere, followed by the age of the convective influence, and last by the extent of convective influence, potentially related to the latitude of convective injection (Dessler and Sherwood, 2004). We find that high-latitude stratospheric air is the dominant source region during the beginning of the campaign while tropical air is the dominant source region during the rest of the campaign. Influence of convection from both local and nonlocal events is frequently observed. The identification of air mass origin is confirmed with backward trajectories, and the behavior of the trajectories is associated with the North American monsoon circulation. Received 28 July 2006; accepted 21 November 2006; published 20 April 2007. Keywords: transport; monsoon; composition. Index Terms: 0341 Atmospheric Composition and Structure: Middle atmosphere: constituent transport and chemistry (3334); 3362 Atmospheric Processes: Stratosphere/troposphere interactions; 0340 Atmospheric Composition and Structure: Middle atmosphere: composition and chemistry; 3319 Atmospheric Processes: General circulation (1223). Read Full Article (file size: 9723420 bytes) Cited by Citation: Pittman, J. V., et al. (2007), Transport in the subtropical lowermost stratosphere during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers–Florida Area Cirrus Experiment, J. Geophys. Res., 112, D08304, doi:10.1029/2006JD007851. Copyright 2007 by the American Geophysical Union.

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