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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, D18111, doi:10.1029/2007JD008685, 2007

Observations of fine-scale transport structure in the upper troposphere from the High-performance Instrumented Airborne Platform for Environmental Research

Kenneth P. Bowman

Department of Atmospheric Sciences, Texas A&M University, College Station, Texas, USA


Laura L. Pan

National Center for Atmospheric Research, Boulder, Colorado, USA


Teresa Campos

National Center for Atmospheric Research, Boulder, Colorado, USA


Rushan Gao

Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA


Abstract

The Progressive Science Mission in December 2005 was the first research use of the new NCAR High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) aircraft. The Stratosphere-Troposphere Analyses of Regional Transport (START) component of the mission was designed to investigate the dynamical and chemical structure of the upper troposphere and lower stratosphere. Flight 5 of the Progressive Science mission was a START flight that sampled near the tropopause in an area between the main jet stream and a large, quasi-stationary, cutoff low. The large-scale flow in this region was characterized by a hyperbolic (saddle) point. In this study the in situ measurements by HIAPER are combined with flow analyses and satellite data to investigate the quasi-isentropic stirring of trace species in the upper troposphere. As expected from theoretical considerations, strong stretching and folding deformation of the flow near the hyperbolic point resulted in rapid filamentation of air masses and sharp gradients of constituents. Calculations of the stirring using operational meteorological analyses from the NCEP Global Forecast System model produced excellent agreement with HIAPER and satellite observations of trace species. Back trajectories indicate that elevated ozone levels in some filaments likely came from a large stratospheric intrusion that occurred upstream in the jet over the north Pacific Ocean. The methods presented here can be used with operational forecasts for future flight planning.

Received 21 March 2007; accepted 11 July 2007; published 26 September 2007.

Keywords: atmospheric transport; mixing; stratosphere-troposphere exchange.

Index Terms: 0368 Atmospheric Composition and Structure: Troposphere: constituent transport and chemistry; 0341 Atmospheric Composition and Structure: Middle atmosphere: constituent transport and chemistry (3334); 3362 Atmospheric Processes: Stratosphere/troposphere interactions; 3319 Atmospheric Processes: General circulation (1223); 4504 Oceanography: Physical: Air/sea interactions (0312, 3339).

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Citation: Bowman, K. P., L. L. Pan, T. Campos, and R. Gao (2007), Observations of fine-scale transport structure in the upper troposphere from the High-performance Instrumented Airborne Platform for Environmental Research, J. Geophys. Res., 112, D18111, doi:10.1029/2007JD008685.