Routine Vertical Profiling

Since its inception in 1992, the NOAA/ESRL/GML Global Greenhouse Gas Reference Network’s Aircraft Program has been dedicated to collecting air samples in vertical profiles over North America. The Ozone and Water Vapor group began sampling with the aircraft program in 2004, and now many sites include an ozone analyzer (see Table). The program's mission is to capture seasonal and inter-annual changes in trace gas mixing ratios throughout the boundary layer and free troposphere (up to 10,000m). At present, most aircraft program flights collect 12 flask samples at different altitudes as well as continuous ozone, temperature, and relative humidity profiles. These flask samples are stored in glass flasks for later analysis of Carbon Dioxide (CO2), Carbon Monoxide (CO), Nitrous Oxide (N2O), Methane (CH4), Molecular Hydrogen (H2), and Sulfur Hexafluoride (SF6), as well as isotopes of CO2 and CH4, and multiple Halo- and Hydrocarbons.

Ozone Instrument inside aircraft
Repackaged 2B Ozone Monitor shown in the front luggage compartment of aircraft that flies profiles over ESRL/GML’s baseline observatory located at Trinidad, CA. Yellow circles highlight the instrument and the inlet location. Both luggage and inlet locations may vary depending on aircraft design. Inlets may be located in a removable pilot window, coming out a wing or forward of the propellers (shown here on a Cessna 340).
Inlet locations may vary depending on aircraft design. Wing inlet on Cessna 210 that flies over Briggsdale, CO.

Vertical profiling at each site occurs at a frequency of 2-3x/week to 1x/month, dependent on the site. For each of these routine flights, the pilot loads equipment into a small aircraft, flies to the desired latitude and longitude (see Table 1) and then ascends to the desired altitude (typically 26,000 ft). The ozone and T/RH are being recorded at 10-second intervals, but in order to fill flask samples, the pilot descends to multiple altitude levels and circles for approximately two minutes to flush and fill each flask. The pilot then ships the flask samples back to NOAA/ESRL for analysis, while only the ozone, GPS coordinates, and T/RH data (rather than the instrument itself) is sent back. Our aircraft data sets contain ozone mixing ratios, GPS coordinates, and T/RH profiles. Data from the flask packages is located through the Interactive Data Viewer.

Code Name Latitude Longitude Elevation (meters) Date of Active Site* (month/year) Country
AAO Airborne Aerosol Observing, Bondville, Illinois 40.05 -88.37 230.0 1/2006-1/2010 United States
BGI Bradgate, Iowa 42.82 -94.41 355.1 6/2005-11/2005 United States
BNE Beaver Crossing, Nebraska 40.80 -97.18 465.9 1/2005-current United States
CAR Briggsdale, Colorado 40.37 -104.30 1740.0 3/2004-current United States
CMA Cape May, New Jersey 38.83 -74.32 0.0 8/2005-current United States
ESP Estevan Point, British Columbia 49.58 -126.37 7.0 3/2009-current Canada
FWI Fairchild, Wisconsin 44.66 -90.96 334.3 7/2005-11/2005 United States
HIL Homer, Illinois 40.07 -87.91 201.5 9/2005-current United States
NHA Worcester, Massachusetts 42.95 -70.63 0.0 5/2005-current United States
OIL Oglesby, Illinois 41.28 -88.94 192.6 9/2005-10/2005 United States
SCA Charleston, South Carolina 32.77 -79.55 0.0 10/2005-current United States
SGP Southern Great Plains, Oklahoma 36.80 -97.50 314.0 6/2006-current United States
THD Trinidad Head, California 41.05 -124.15 107.0 4/2005-current United States
ULB Ulaanbaatar 47.40 106.00 1350.0 11/2004-10/2008 Mongolia
WBI/RIA West Branch, Iowa/Rowley, Iowa 41.73/42.40 -91.35/-91.84 241.7/298.7 1/2005-5/2011 United States
Tropospheric Aircraft Ozone Measurement Program’s site locations and measurement collection dates.
*Ozone measurement data is available during active site dates.