ESSL LAR

Laura Pan (Ting)

 

Scientist II
TIIMES - ACD
UTLS

 

Contact Information:
PO Box 3000, Boulder, CO 80307-3000
Office: FL0-2160
Telephone: 303-497-1467
Email: liwen@ucar.edu
Home Page

Laura Pan
 

Project Summary:

START-05 Data-Ozone & Water Vapor

Click on picture to view the entire figure.


Figure 1: Tracer-tracer correlation (top) from ozone and water vapor measured December 1, 2005, onboard HIAPER during the START experiment, identifies the stratosphere airmass (red), troposphere airmass (green) and a mixture (blue). These identifications are mapped back to the flight track (bottom), together with the background meteorological field, based on NCEP GFS analyses. This analyses shows that the mixed air mass is minimal on the anticyclonic (equatorward) side of the jet (jet position is shown as gray shaded region), but extensive on the cyclonic (poleward) side of the jet.

During FY07, Laura Pan has been working on data analyses from the Stratosphere Troposphere Analyses of Regional Transport (START-05) and Terrain-Induced Rotor Experiment Main Study Page (TREX) field campaign investigate chemical transport and mixing near the extratropical tropopause.  The main scientific issues are related to the question of how the dynamical processes of different scale control the chemical composition of the upper troposphere and lower stratosphere (UTLS).

 

START-05 campaign

The questions related to the behavior of the extratropical tropopause were investigated using the aircraft measurements made on NSF/NCAR G-V during the Stratosphere Troposphere Analyses of Regional Transport (START-05) experiment, conduced during the HIAPER Progressive Science missions December 2005.

Using ozone and water vapor measurements onboard the GV and tracer correlation technique, air masses of mixed stratospheric and tropospheric characteristics were identified. This analysis for the first research flight of HIAPER aircraft is shown in Figure 1. As the figure indicates, a depth of mixed air (~5 km in vertical distribution) was found on the cyclonic side of the polar jet, where the thermal gradient is weak and significant separation occurs between the thermal and the dynamical tropopause.  Away from the jet or on the anticyclonic side of the jet, where the stability gradient was strong, the chemical transition across the tropopause was much more abrupt and shows minimum mixing.  The results of this analysis suggest that, if the extratropical tropopause is treated as a transition layer, the thickness of the layer appears to have strong spatial variation.  The depth of transition layer will be the subject of further investigated in upcoming experiment START-08.

This result also suggests that significant mixing maybe associated with the region where the dynamical tropopause is significantly below the thermal tropopause.  We have examined this relationship using global satellite measurements of ozone and water vapor from AIRS on Aqua satellite.  The result is consistent with the aircraft observations.

 

TREX - Ozone & CO time series

Click on picture to view the entire figure.


Figure 2. The time series of O3 and CO during a 7 minutes segment of the ferry leg of flight 9 (April 15, 2006). The flight segment was over central Nevada (38.6N and 115W) and at 47 Kft pressure altitude. The estimated GV speed was ~260 m/s. The two groups of waves have estimated wavelength of ~9 km.

T-REX campaign

The Terrain-Induced Rotor Experiment Main Study Page (TREX) is a coordinated effort to explore the structure and evolution of atmospheric rotors. The main scientific objective of T-REX is a comprehensive study of the coupled mountain-wave, rotor, and boundary-layer system.  T-REX field activities took place in Owens Valley in March and April 2006.

In addition to the meteorological parameters, a small suite of chemical tracers, including ozone (O3), carbon monoxide (CO) and water vapor (H2O), were measured onboard the G-V during the T-REX mission.  The ozone measurements were made with the NCAR Ozone Chemiluminescence instrument. The CO measurements were made with a VUV resonance fluorescence instrument. The water vapor was measured with a MayComm Open-Path Laser Hygrometer (OPLH) sensor.  All three instruments were providing data at ~ 1 second sampling rate.   These tracers provide information on perturbations of the chemical composition in the upper troposphere and lower stratosphere (UTLS) by the mountain waves. The variation and correlation of these tracers provide a unique perspective how the air mass is affected by the waves and whether mixing has occurred.  In particular, O3 and CO are frequently used tracers in stratosphere-troposphere exchange (STE) studies [Fischer et al., 2000; Zahn et al., 2000; Hoor et al., 2002; Pan et al., 2004].   O3 increases rapidly above the tropopause and is often used as a tracer for stratospheric air.  CO, on the other hand, decreases rapidly above the tropopause and is used as a tracer for the tropospheric air.  The mixing ratios of both tracers go through steep gradients in the tropopause region, which helps identify the chemical transition from stratosphere to troposphere. The correlation between the two tracers often highlights the mixing between the stratospheric and tropospheric air masses.  The measurements of tracers and tracer relationships during T-REX will be compared with background statistics based on past measurements to study the impact of mountain waves to the chemical transition across the tropopause.

During the T-REX missions, the chemical tracers have also shown to be a very effective measure of the wave activities, providing strong signals of waves throughout the UTLS.  A striking case of mountain wave perturbation to the lower stratospheric chemical distribution was observed on T-REX flight 9 (April 15) after exiting the T-REX IOP box. As the G-V ascended to 47Kft level over the mountain ranges of central Nevada  (the area of Toiyabe national forest), large amplitude waves began to appear in the ozone signal. Several groups of mountain waves were seen in the ozone data, with large amplitudes of greater than 300 ppbv in ozone mixing ratio, which represent a factor of 2 or more in the change of flight level ozone values.   Figure 2 shows the O3 and CO time series for a 7 minute segment of this flight. The mountain wave signature in the CO time series is anti-correlated with O3. The O3 and CO forms a compact relationship in the tracer space.  Comparisons with measurements in similar latitude and season will be made to characterize the influence of the wave to the vertical mixing of the chemical tracers.
 

Community Service:

  • Member - AMS Middle Atmosphere committee, American Meteorological Society (AMS)
  • Member - AMS Middle Atmosphere, American Meteorological Society (AMS)
  • Member - IAMAS/International Commission on Middle Atmosphere (ICMA), The International Association of Meteorology and Atmospheric Sciences (IAMAS)
  • Member - International Commission on Middle Atmosphere (ICMA), The International Association of Meteorology and Atmospheric Sciences (IAMAS)
 

Presentations:

  • Chemical Behavior of the Tropopause observed during the first year HIAPER operation, Boulder USA, October 2006
  • Chemical Behavior of the Tropopause Observed during the Stratosphere-Troposphere Analyses of Regional Transport (START) experiment, San Francisco USA, December 2006
  • Chemical Behavior of the Tropopause, Beijing CHN, November 2006
  • Chemical Behavior of the Tropopause, College Station USA, November 2006
  • Chemical Behavior of the Tropopause, College Station USA, October 2006
  • Chemical Behavior of the Tropopause, Peking CHN, November 2006
  • Observational Study of the Extratropical Tropopause during the first year of HIAPER Operation, Oberpfaffenhofen DEU, April 2007
  • Observational Study of the Extratropical Tropopause during the first year of HIAPER Operation, Boulder USA, April 2007
  • Observational Study of the Extratropical Tropopause, Beijing CHN, November 2006
  • Observational Study of the Extratropical Tropopause, Vienna AUS, April 2007
 

TIIMES External Collaborators:

Joan Alexander, NorthWest Research Associates
Elliot Atlas, University of Miami
Linnea Avallone, University of Colorado
Chris Barnet, National Oceanic & Atmospheric Administration (NOAA)
Timothy Bertram, University of California, Berkeley
Jianchun Bian, Chinese Academy of Sciences
Greg Bodeker, National Institute of Water & Atmospheric Research (NIWA)
Kenneth Bowman, Texas A&M University
Wiliam Brune, Pennsylvania State University
Tony Clarke, University of Hawaii
Ron Cohen, University of California, Berkeley
Owen Cooper, University of Colorado
James Crawford, Langley Research Center (LARC) - NASA
Joost deGouw, National Oceanic & Atmospheric Administration (NOAA) - ERL
Timothy Dunkerton, NorthWest Research Associates
Jim Elkins, National Oceanic & Atmospheric Administration (NOAA)
Steve Gahn, Pacific Northwest National Laboratory
Ru-Shan Gao, National Oceanic & Atmospheric Administration (NOAA)
Tim Garrett, University of Utah
George Grell, University of Colorado
Michaela Hegglin, University of Toronto
John Helsdon, South Dakota School of Mines & Technology (SDSMT)
Chen Hongbin, Chinese Academy of Sciences
Steve Howell, University of Hawaii
Greg Huey, Georgia Institute of Technology
Dale Hurst, University of Colorado-Cooperative Institute for Research in Environmental Sciences (CIRES)
Jose-Luis Jimenez, University of Colorado
Si-Wan Kim, National Oceanic & Atmospheric Administration (NOAA) - ESRL, University of Colorado
Paul Konopka, Research Center-Juelich
Paul Krehbiel, New Mexico Institute of Technology
Timothy Lang, Colorado State University
Andy Langford, National Oceanic & Atmospheric Administration (NOAA) - ESRL
Don MacGorman, National Oceanic & Atmospheric Administration (NOAA) - NSSL
Adrian McDonald-Buller, Canterbury University
Kathleen Monahan, Canterbury University
Fred Moore, University of Colorado-Cooperative Institute for Research in Environmental Sciences (CIRES)
Rolf Mueller, Research Center-Juelich
Gretchen Mullendore, University of California, Los Angeles
Walter Petersen, University of Alabama, Huntsville
Kenneth Pickering, Goddard Space Flight Center (GSFC) - NASA
Lorenzo Polvani, Columbia University
Steven Rutledge, Colorado State University
Kim Si-Wan, National Oceanic & Atmospheric Administration (NOAA) - ESRL, University of Colorado
Darin Toohey, University of Colorado
Wen-wen Tung, Purdue University
Pao Wang, University of Wisconsin
Jennifer Wei, National Oceanic & Atmospheric Administration (NOAA)
Charles Wilson, University of Denver
Steve Wofsy, Harvard University
Fuqing Zhang, Texas A&M University
Mark Zondlo, Southwest Sciences
 

Publications:

Monaham, K. P., L. L. Pan, A. J. McDonald, G. E. Bodeker, J. Wei, S. E. George, C. D. Barnet, E. Maddy, 2007: Validation of AIRS v4 ozone profiles in the UTLS using ozonesondes from Lauder, NZ and Boulder, USA. J. Geophys. Res., 112, D17304, doi: 10.1029/2006JD008181.

Bowman, K. P., L. L. Pan, T. Campos, 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., American Geophysical Union, 112, D18111, doi: 10.1029/2007JD008685.

Pan, L. L., K. P. Bowman, M. Shapiro, W. J. Randel, R. S. Gao, T. Campos, C. Davis, S. Schauffler, B. A. Ridley, J. C. Wei, C. Barnet, 2007: Chemical behavior of the tropopause observed during the Stratosphere-Troposphere Analysis of Regional Transport experiment. J. Geophys. Res., American Geophysical Union, 112, D18110, doi: 10.1029/2007JD008645.

Konopka, P., G. Guenther, R. Mueller, F. H. S. dos Santos, C. Schiller, F. Ravegnani, A. Ulanovsky, H. Schlager, C. M. Volk, S. Viciani, L. L. Pan, D.-S. McKenna, M. Riese, 2007: Contribution of mixing to upward transport across the tropical tropopause layer (TTL). Atmos. Chem. Phys., 7, 3285-3308.

Pan, L. L., J. C. Wei, D. E. Kinnison, R. R. Garcia, D. J. Wuebbles, G. P. Brasseur, 2007: A set of diagnostics for evaluating chemistry-climate models in the extratropical tropopause region. J. Geophys. Res., 112, D09316, doi: 10.1029/2006JD007792.

Randel, W. J., D. J. Seidel, L. L. Pan, 2007: Observational characteristics of double tropopauses. J. Geophys. Res., 112, D07309, doi: 10.1029/2006JD007904.

Young, L.-H., D. R. Benson, W. M. Montanaro, S.-H. Lee, L. L. Pan, D. C. Rogers, J. Jensen, J. L. Stith, C. A. Davis, T. L. Campos, K. P. Bowman, W. A. Cooper, L. R. Lait, 2007: Enhanced new particle formation observed in the northern midlatitude tropopause region. J. Geophys. Res., 112, D10218, doi: 10.1029/2006JD008109.

Kinnison, D. E., G. P. Brasseur, S. Walters, R. R. Garcia, D. R. Marsh, F. Sassi, V. L. Harvey, C. E. Randall, L. Emmons, J. F. Lamarque, P. Hess, J. J. Orlando, X. X. Tie, W. Randel, L. L. Pan, A. Gettelman, C. Granier, T. Diehl, U. Niemeier, A. J. Simmons, 2007: Sensitivity of chemical tracers to meteorological parameters in the MOZART-3 Chemical Transport Model. J. Geophys. Res.. (In Press)

Bian, J. C., A. K. Gettelman, H. Chen, L. L. Pan, 2007: Validation of satellite ozone profile retrievals using Beijing ozonesonde data. J. Geophys. Res., 112, D06305, doi: 10.1029/2006JD007502.