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Research Programs

Upper Tropopshere / Lower Stratosphere Initiative
FY2006 activities

TIIMES Theme:
UTLS

Compiled by Laura Pan - ACD - TIIMES

Research Teams:

  • START05:
    Investigators: Kenneth Bowman (Texas A&M University), Teresa Campos--ACD, Chris Davis-MMM, Ru-shan Gao (NOAA-ESRL), Laura Pan-ACD& TIIMES, William Randel-ACD, Sue Schauffler-ACD, Melvyn Shapiro-MMM
    Internal Collaborators: Jorgen Jensen-EOL, William Cooper-EOL, David Rogers-EOL, Jeffrey Stith-EOL
    External Collaborators: Christopher Barnet (NOAA-NESDIS), Jennifer Wei (NOAA-ESRL)

  • T-REX:
    UTLS Investigators: Teresa Campos-ACD, Laura Pan-ACD& TIIMES, Ilana Pollack-ACD, William Randel-ACD, Brian Ridley-ACD, Sue Schauffler-ACD, Andy Weinheimer-ACD
    Key Internal Collaborators: Joachim Kuettner(JOSS)
    Key External Collaborators: James Doyle (NRL), Vanda Grubisic (DRI), Ron Smith (Yale)

  • START08:
    Principal investigators: Elliot Atlas (University of Miami), Laura Pan-ACD& TIIMES

  • DC3:
    Principal investigators: Mary Barth-ACD, William Brune (Penn State), Chris Cantrell-ACD, Steven Rutledge (CSU)

UTLS
Flight track for the first research flight of HIAPER

Flight track for the first research flight of HIAPER and the dynamical tropopause during a tropopause fold sampled by the aircraft during the flight (December 1, 2005).

measurements of ozone and water vapor on board the aircraft

In situ measurements of ozone and water vapor on board the aircraft. Using the correlation of these two tracers, mixing between the stratosphere and troposphere is identified (blue points).

The region of  ~5 kilometers above and below the tropopause is usually referred to as the upper troposphere and lower stratosphere (UTLS). Investigation of the processes occurring in the UTLS is crucial for understanding long-term global climate change and tropospheric air quality. The interaction between chemistry and clouds in this region and the perturbations of dynamical processes to the radiatively-sensitive species on both sides of the tropopause presents a challenge to the performance of climate models. The new Gulfstream V (G-V+) research aircraft, with its high altitude and long-range capabilities, offers new and exciting opportunities for photochemistry, cloud, aerosol, radiation, and transport research in this region. The goals of the UTLS Initiative are to plan and conduct field campaigns, using this new aircraft, to investigate the coupled dynamical, chemical and microphysical processes in the UTLS and to complement the aircraft studies with satellite observations and multiscale NCAR models.

During FY06, the UTLS Initiative team participated in the first two field deployments of the G-V and obtained initial results of observing the UTLS region from the new aircraft. The first experiment, the Stratosphere-Troposphere Analyses of Regional Transport (START05), was conducted as a component of the G-V Progressive Science Mission in December, 2005. The behavior of the tropopause as a chemical transport boundary was observed under a variety of dynamical conditions. The experiment was led jointly by staff from the Earth and Sun Systems Laboratory - ESSL (Laura Pan, William Randel, Melvyn Shapiro, Christopher Davis, Teresa Campos, and Sue Schauffler) and staff from the Earth Observing Laboratory - EOL (William Cooper, Jorgen Jensen, Jeffrey Stith, David Rogers), along with external collaborators Ru-shan Gao (National Oceanic and Atmospheric Administration/Earth System Research Laboratory [NOAA/ESRL]), Kenneth Bowman (Texas A&M University), Jennifer Wei and Christopher Barnet (NOAA/National Earth Satellite Data and Information System [NESDIS]). These initial flights successfully demonstrated the new aircraft’s capability to sample detailed structure in the region of tropopause folds. The second experiment, Terrain-induced Rotor Experiment (T-REX) was conducted during March-April, 2006. ESSL staff who participated include Pan, Ilana Pollack, Campos, Brian Ridley, Schauffler, and Randel), in collaboration with the T-REX Science Team (led by Vanda Grubisic, Desert Research Institute), investigated the chemical signature of mountain waves near the tropopause. Using a small suite of in situ tracer measurements (O3, CO and H2O vapor) and analyses of meteorological variables, transport pathways between the stratosphere and troposphere were probed during these two field experiments.

Two more extensive field experiments have been planned for FY07-09 (START08 Experiment [FY08] and Deep Convective Clouds and Chemistry (DC3) Experiment [FY09]). The focus in FY07 is to carry out the planning, proposal, and preparation for these two experiments. The START08 experiment, with an instrument payload to measure chemical and microphysical tracers will identify the transport pathways and characterize the transport boundary in the extratropical UTLS region. The DC3 experiment targets the chemical impact of the convective transport and cloud processing. Results from both experiments will contribute to the observational database for process-oriented validation and diagnoses of chemistry-climate models. Co-leading the START08 effort are Elliot Atlas (University of Miami) and Pan. The DC3 effort is co-led by Mary Barth (NCAR), Christopher Cantrell (NCAR), William Brune (Pennsylvania State University) and Steven Rutledge (Colorado State University).