Related Research Areas
Atmospheric Composition

In attempting to quantify anthropogenic sources for tropospheric ozone, stratosphere- troposphere exchange (STE) remains a major contributor. An improved understanding of ozone structures involved in STE would improve our capability to model the distribution of ozone and other important trace constituents. It would also improve our understanding of transport pathways during STE and the dynamics of the upper troposphere and lower stratosphere (UTLS). Current global atmospheric models which assimilate satellite constituent distributions, such as NASA’s Global Earth Observing System (GEOS), can represent ozone structures in the UTLS in association with STE. Yet comparison with in situ data shows that fine structure is not adequately represented in some cases.
Significant uncertainty also exists in our knowledge of synoptic / mesoscale dynamical processes in the UTLS associated with STE, especially details of transport pathways in the lowest stratosphere.
Questions to be addressed include: 1) What are typical errors in ozone near tropopause folds and how do they depend on model resolution? 2) How can we improve representation of STE and ozone transport in numerical models? Ozone error statistics will be grouped by synoptic situation, with analysis of the dynamical structure and transport guiding recommendations for enhancements in simulations and observations.
Associated dynamical questions include: 3) How do the ozone transport pathways in the UTLS relate to Rossby wave breaking and the energetics of baroclinic life cycles? 4) What role do inertia-gravity waves and PV streamers play in creating ozone structures in the UTLS during STE? Detailed analysis of ozone structures in explicit UWNMS representations of synoptic and inertia-gravity waves will be carried out for selected weather events. Idealized tracers and trajectories in the UWNMS are useful for illuminating complex air mass pathways.
We propose to analyze ozone structures in the UTLS associated with STE, including the warm conveyor belt, dry intrusion, and split pathways, informed by detailed tracer observations and high resolution modeling. The University of Wisconsin Nonhydrostatic Modeling System (UWMNS) will be driven by GEOS data for selected periods of 2005 and 2006 for comparison with in situ ozone and satellite data.
In the first phase we will intercompare Mt. Bachelor surface ozone, commercial aircraft observations from the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) project, and INTEX-B Ozonesonde Network Study, 2006 (IONS-06) data. In the second phase, satellite ozone data from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) and the Atmospheric InfraRed Sounder (AIRS) instruments will be compared with UNWMS / GEOS ozone structures.
This intercomparison across in situ data, satellite data, and nested assimilation models will improve understanding of air mass pathways in the UTLS, energetics and mixing during synoptic Rossby wave breaking, ozone STE, and of the dynamical settings for ozone errors in global models. This proposal in the area of atmospheric composition would integrate satellite, aircraft, balloon, ground-based observations, and models, with a focus in stratosphere-troposphere exchange. It will contribute to our understanding of how the general circulation controls the distribution of climatically important trace gases.

Project PI: Matthew Hitchman/University of Wisconsin - Madison

Department of Atmospheric and Oceanic Sciences University of Wisconsin - Madison 1225 West Dayton Street Madison, WI 53706

Phone: (608) 262-4653



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Started: Sep 03, 2010

Last Activity: Feb 02, 2011


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