UTLS Science:

UTLS - Science - START-05 Campaign

START-05

(Stratosphere-Troposphere Analyses of Regional Transport)

HIAPER Progressive Science Mission
21 November - 23 December 2005

Investigators (see information to the right)

Internal Collaborators:
Jorgen Jensen (EOL), William Cooper (EOL), David Rogers (EOL), Jeffrey Stith (EOL)

External Collaborators:
Christopher Barnet (NOAA-NESDIS), Jennifer Wei (NOAA-ESRL)

Principal Investigators

Laura Pan
NCAR
303.497.1467

Co-Investigators

Teresa Campos
NCAR

Mel Shapiro
NCAR

Figure 1.
G-V flight track for START05 Flight 1, 2005-12-01. The 2 PVU surface (orange), based on NCEP/GFS analyses, indicates the spatial structure of a tropopause fold sampled by G-V. Colors on the flight track indicate the in situ ozone value from measurement on board G-V.

Figure 2. 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.

Figure 3. The G-V flight track for START05 flight 1 colored according to the classifications given in Figure 2. Also shown in the figure are GFS based potential vorticity contours (black solid), thermal tropopause (black broken), isentropes (magenta), and the position of the jet core (gray shaded).

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 (START-05), 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 by staff from the Earth and Sun Systems Laboratory - ESSL (Laura Pan, William Randel, Melvyn Shapiro, Christopher Davis, Teresa Campos, and Sue Schauffler) and in collaboration with 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 Future:

Two more extensive field experiments have been planned for FY07-09 (START08 Experiment [FY08] and Deep Convective Clouds and Chemistry (DC3) Experiment [FY10]). The focus in FY07 is to carry out the planning, proposal, and preparation for these two experiments. Click on the links provided for additional information.

Publications:

Pan, L. L., K. P. Bowman, M. Shapiro, W. J, Randel, R. Gao, T. Campos, C. Davis, S. Schauffler, B. A. Ridley, J. C. Wei, and C. Barnet, Chemical Behavior of the Tropopause Observed during the Stratosphere-Troposphere Analyses of Regional Transport (START) experiment, submitted to J. Geophys. Res., 2007.
Bowman, K., P., L. L. Pan, Teresa Campos, and Rushan Gao, Observations of fine-scale transport structure in the upper troposphere from HIAPER, submitted to J. Geophys. Res., 2007.
Young, L-L., James C. Wilson, David R. Benson1, William M. Montanaro, Shan-Hu Lee, Laura L. Pan, David C. Rogers, Jorgen Jensen, Jeff Stith, Christopher A. Davis, Teresa L. Campos, Kenneth P. Bowman, William A. Cooper, and Leslie R. Lait, Enhanced New Particle Formation Observed in the Northern Midlatitude Tropopause Region, J. Geophys. Res., in press 2007.