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Information

Aircraft Home Newsletters

Methods

Sampling Measurements Data Archive Quality Control

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Special Projects

Data

Data Data Visualization (IADV) Publications

Aircraft Program

aircraft flying over mountains during measurement campaign

Latest News

NOAA and United Airlines partner to measure greenhouse gases, pollutants with high-tech flight instruments

July 23, 2024

NOAA and United Airlines announced an agreement to equip a Boeing 737 with a sophisticated instrument package that will measure greenhouse gases and other pollutants during domestic flights. It’s a first step in establishing a partnership that could significantly improve monitoring of carbon dioxide, methane and other greenhouse gases, and improve weather forecast accuracy in the United States.

Overview

GML’s Aircraft Program supports multiple measurement and monitoring efforts that include regular sampling at sites across the United States under the Global Greenhouse Gas Reference Network, intensive sampling campaigns, and the NOGAP (National Observations of Greenhouse gases Aircraft Profiles) program that samples the atmosphere in a near continuous path around the continental U.S. with the objective of filling sampling gaps.

The aircraft program's mission is to capture seasonal and interannual changes in greenhouse gas concentrations in the lower part of Earth’s atmosphere. The small aircraft collect samples in flasks at sites across the United States (including Alaska and Canada) while descending from altitudes as high as 8000m/26000 ft.

In recent years, GML has developed a commercial aircraft program with instruments that directly sample the atmosphere at a near-continuous rate. This program includes mid-size passenger planes, which allow for a significant increase in the altitude (12,000m/39,000ft) and frequency of measurements, and smaller commercial aircraft.

GML has made dedicated measurements with small planes in Africa and Brazil. A recently announced collaboration with United Airlines will fly instruments on Boeing 737 aircraft on flights to metropolitan areas throughout the United States and in neighboring countries. More frequent flights will improve monitoring in urban regions that produce the majority of U.S. greenhouse gas emissions.

Air collected in GML’s aircraft program is analyzed for carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), and water vapor. Samples taken using flasks can also be analyzed for nitrous oxide (N2O), molecular hydrogen (H2), and sulfur hexafluoride (SF6), as well as isotopes of CO2 and CH4 and multiple halo- and hydrocarbons.

These measurements help us understand changes in the large-scale horizontal and vertical distribution of the major and minor greenhouse gases across the United States. They also improve our ability to better understand specific sources of greenhouse gas emissions. Data are publically available via NOAA’s Global Greenhouse Gas Reference Network, a foundational tool used by climate scientists.

Project Goals and Instrumentation

GML’s Aircraft Program has been developed to deliver:
  1. Better understanding of vertical gradients of greenhouse gases in the atmosphere that ground- or satellite-based instruments can’t accurately capture
  2. Direct measurements of greenhouse gases in the atmospheric column to compare, contrast, and improve satellite column estimates of GHGs
  3. More accurate model estimates of greenhouse gas emissions through improved representation of the vertical gradients in greenhouse gases

A key feature of GML’s Aircraft Program is the development of automated systems—whether portable, automated flask sampling systems or instruments that remain unattended for continuous measurements and subsequent upload to GML—eliminating the need for on-site technical expertise.

Sites

Yellow markers indicate discontinued sites
Code Name Lat Lon Elevation (masl) Status Bottom altitude (m) Top altitude (m) Average Flight Frequency1 (days)
AAO Airborne Aerosol Observatory, Bondville, Illinois 40.0500 -88.3700 230.00 Terminated 374 4860 4
ACG Alaska Coast Guard 57.7366 -152.5042 6.00 Ongoing 0 9291 99
AFO Africa Aircraft Flights of Opportunity -25.9900 28.1400 -9999.99 Ongoing Not available
BGI Bradgate, Iowa 42.8200 -94.4100 355.10 Terminated 599 8075 14
BNE Beaver Crossing, Nebraska 40.8000 -97.1800 465.90 Terminated 597 8157 27
CAR Briggsdale, Colorado 40.6347 -104.3269 1488.00 Ongoing 1586 11879 19
CMA Offshore Cape May, New Jersey 38.8300 -74.3200 0.00 Ongoing 247 8143 12
CRV Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) 64.9863 -147.5980 611.43 Terminated 2 7850 9
DND Dahlen, North Dakota 47.5000 -99.2400 472.44 Terminated 518 8131 19
ESP Estevan Point, British Columbia 49.3830 -126.5441 7.00 Ongoing 18 5820 13
ETL East Trout Lake, Saskatchewan 54.3541 -104.9868 493.00 Ongoing 599 7823 22
FAM FAAM Aircraft -99.9999 -999.9999 -9999.99 Terminated 129 2000 38
FTL Fortaleza -3.5200 -38.2800 3.00 Terminated 152 4267 93
FWI Fairchild, Wisconsin 44.6600 -90.9600 334.30 Terminated 590 8073 14
GAP National Observations of Greenhouse Gases using Aircraft Profiles (NOGAP) -99.9999 -999.9999 -9999.99 Ongoing 123 6553 5
HAA Molokai Island, Hawaii 21.2300 -158.9500 3.00 Terminated 4 8104 21
HFM Harvard Forest, Massachusetts 42.5378 -72.1714 340.00 Terminated 582 8063 19
HIL Homer, Illinois 40.0700 -87.9100 201.50 Ongoing 322 8117 14
HOW Howland, Maine 42.2000 -68.1300 -9999.99 Terminated 122 3048 184
INX INFLUX (Indianapolis Flux Experiment) 39.5805 -86.4207 -9999.99 Terminated 302 3518 40
LEF Park Falls, Wisconsin 45.9451 -90.2732 472.00 Ongoing 537 5060 20
NHA Offshore Portsmouth, New Hampshire (Isles of Shoals) 42.9500 -70.6300 0.00 Ongoing 0 8136 15
NSK Northern Saskatchewan 58.7300 -104.9000 401.00 Terminated 820 6799 24
OIL Oglesby, Illinois 41.2800 -88.9400 192.60 Terminated 530 8121 12
PFA Poker Flat, Alaska 64.9000 -148.7600 210.00 Ongoing 131 7618 16
RTA Rarotonga -21.2500 -159.8300 3.00 Ongoing 13 6528 21
SAN Santarem -2.8500 -54.9500 78.00 Terminated 300 5200 43
SCA Offshore Charleston, South Carolina 32.7700 -79.5500 0.00 Ongoing 218 13279 23
SGP Southern Great Plains, Oklahoma 36.6070 -97.4890 314.00 Ongoing 152 12949 16
TGC Offshore Corpus Christi, Texas 27.7300 -96.8600 0.00 Ongoing 19 8255 16
THD Trinidad Head, California 41.0541 -124.1510 107.00 Ongoing 152 8131 17
UGD Kajjansi Airfield, Kampala, Uganda 0.2000 32.5500 1141.00 Terminated Not available
ULB Ulaanbaatar 47.4000 106.0000 1350.00 Terminated 1512 5944 25
WBI West Branch, Iowa 41.7248 -91.3529 241.70 Ongoing 543 8204 14
WGC Walnut Grove, California 38.2645 -121.4904 2.00 Terminated 6 3177 19
1 Average number of days between flights during the last two years of sampling.

Airborne Aerosol Observatory, Bondville, Illinois (AAO)

40.0500 °N | 88.37 °W | 230.00 m

  • First Sample Date: 2006-06-07
  • Last Sample Date: 2009-09-18
  • Top Altitude: 4860 m/15944 ft
  • Bottom Altitude: 374 m/1227 ft
  • Average Flight Frequency: Every 4 days
  • Aircraft: Fixed Wing Single-Engine T206H Cessna
  • Status: Terminated
  • Data Visualization
Plane used at AAO
Sample Inlet on AAO plane
The NOAA Airborne Aerosol Observatory was a mobile observatory based near Bondville, Illinois. Samples were collected over the flat, agricultural lands of east central Illinois. The AAO aircraft is specifically outfitted for atmospheric monitoring. Instruments on the aircraft make measurements of aerosol optical properties, hygroscopic growth, aerosol composition, particle number, and size distribution. In addition to aerosol measurements, the aircraft also carried the automated sampling equipment for carbon cycle gas collection. AAO was one of the most frequently sampled locations, often conducting two sampling flights per week. Sample collection began in June 2006, but the site was discontinued in September 2009 because of funding cuts.

Alaska Coast Guard (ACG)

57.7366 °N | 152.5042 °W | 6.00 m

  • First Sample Date: 2009-04-30
  • Last Sample Date: 2024-09-26
  • Top Altitude: 9291 m/30482 ft
  • Bottom Altitude: 0 m/0 ft
  • Average Flight Frequency: Every 102 days
  • Aircraft:
  • Status: Ongoing
  • Data Visualization
Plane used at ACG

Africa Aircraft Flights of Opportunity (AFO)

-25.9900 °N | 28.14 °E | -9999.99 m

  • First Sample Date: 2023-06-29
  • Last Sample Date: 2023-12-14
  • Top Altitude: m/0 ft
  • Bottom Altitude: m/0 ft
  • Average Flight Frequency: Not available
  • Aircraft:
  • Status: Ongoing
  • Data Visualization

Bradgate, Iowa (BGI)

42.8200 °N | 94.41 °W | 355.10 m

  • First Sample Date: 2004-09-13
  • Last Sample Date: 2005-11-18
  • Top Altitude: 8075 m/26492 ft
  • Bottom Altitude: 599 m/1965 ft
  • Average Flight Frequency: Every 14 days
  • Aircraft: Cessna 421B
  • Status: Terminated
  • Data Visualization
Plane used at BGI
Sample Inlet on BGI plane
BGI samples were collected over flat, agricultural lands near Bradgate in northwestern Iowa. Sample collection at BGI started in September 2004, but the site was discontinued in November 2005 because of funding cuts. BGI flights were conducted by Jeff Smalley and Dr. Dirk Brom of Hap’s Air Service based in Ames, Iowa.

Beaver Crossing, Nebraska (BNE)

40.8000 °N | 97.18 °W | 465.90 m

  • First Sample Date: 2004-09-15
  • Last Sample Date: 2011-05-11
  • Top Altitude: 8157 m/26761 ft
  • Bottom Altitude: 597 m/1958 ft
  • Average Flight Frequency: Every 30 days
  • Aircraft: Cessna 421B
  • Status: Terminated
  • Data Visualization
Plane used at BNE
Sample Inlet on BNE plane
Samples are collected over flat, agricultural land near Beaver Crossing in southeastern Nebraska. Sample collection at BNE started in September 2004. These flights are conducted by Jeff Smalley and Dr. Dirk Brom of Hap’s Air Service based in Ames, Iowa.

Briggsdale, Colorado (CAR)

40.6347 °N | 104.3269 °W | 1488.00 m

  • First Sample Date: 1992-11-09
  • Last Sample Date: 2025-04-10
  • Top Altitude: 11879 m/38973 ft
  • Bottom Altitude: 1586 m/5203 ft
  • Average Flight Frequency: Every 18 days
  • Aircraft: Cessna 210
  • Status: Ongoing
  • Data Visualization
Plane used at CAR
Sample Inlet on CAR plane
Samples are collected over flat, mixed plains and agricultural land near Briggsdale in northeastern Colorado. The Carbon Cycle group’s longest vertical-profile record comes from this area, with sample collection beginning in November 1992 during the initial development and testing phase of the automated flask sampling system. Sampling flights were originally conducted over Carr, Colorado, but in December 2004 the site was moved 40 miles southeast to Briggsdale to be in proximity to an Ameriflux tower. Regular sampling flights continue to be flown, but CAR also acts as the test site for new and modified sampling equipment. Flights at CAR are conducted by John Weisbart, ATP, of Weisbart Aircraft Services, LLC.

Offshore Cape May, New Jersey (CMA)

38.8300 °N | 74.32 °W | 0.00 m

  • First Sample Date: 2005-08-17
  • Last Sample Date: 2025-04-09
  • Top Altitude: 8143 m/26715 ft
  • Bottom Altitude: 247 m/810 ft
  • Average Flight Frequency: Every 11 days
  • Aircraft: Cessna Piper Comanche Twin
  • Status: Ongoing
  • Data Visualization
Plane used at CMA
Sample Inlet on CMA plane
CMA samples are collected over the Atlantic Ocean off the coast of Cape May, New Jersey. Sample collection at CMA started in August 2005.

Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) (CRV)

64.9863 °N | 147.598 °W | 611.43 m

  • First Sample Date: 2017-04-26
  • Last Sample Date: 2017-11-05
  • Top Altitude: 7850 m/25754 ft
  • Bottom Altitude: 2 m/6 ft
  • Average Flight Frequency: Every 14 days
  • Aircraft:
  • Status: Terminated
  • Data Visualization
Plane used at CRV
Sample Inlet on CRV plane

Dahlen, North Dakota (DND)

47.5000 °N | 99.24 °W | 472.44 m

  • First Sample Date: 2004-09-21
  • Last Sample Date: 2016-11-15
  • Top Altitude: 8131 m/26676 ft
  • Bottom Altitude: 518 m/1699 ft
  • Average Flight Frequency: Every 16 days
  • Aircraft: Cessna 340A
  • Status: Terminated
  • Data Visualization
Plane used at DND
Sample Inlet on DND plane
Samples are collected over flat, agricultural land in northeastern North Dakota. Sample collection at DND started in November 2004.

Estevan Point, British Columbia (ESP)

49.3830 °N | 126.5441 °W | 7.00 m

  • First Sample Date: 2002-11-22
  • Last Sample Date: 2025-03-06
  • Top Altitude: 5820 m/19094 ft
  • Bottom Altitude: 18 m/59 ft
  • Average Flight Frequency: Every 12 days
  • Aircraft: Cessna 182
  • Status: Ongoing
  • Data Visualization
Plane used at ESP
Sample Inlet on ESP plane
Samples are collected over the Estevan Point Lighthouse on the west coast of Vancouver Island, British Columbia. Sample collection at ESP started in November 2002. Flights are conducted by Hal Schulz who is based in Comox, British Columbia.

East Trout Lake, Saskatchewan (ETL)

54.3541 °N | 104.9868 °W | 493.00 m

  • First Sample Date: 2005-10-15
  • Last Sample Date: 2025-02-25
  • Top Altitude: 7823 m/25666 ft
  • Bottom Altitude: 599 m/1965 ft
  • Average Flight Frequency: Every 23 days
  • Aircraft: Beechcraft King Air A100
  • Status: Ongoing
  • Data Visualization
Plane used at ETL
Sample Inlet on ETL plane
Samples are collected over forest land in central Saskatchewan and directly above a tower beside East Trout Lake, Saskatchewan. Flights are synchronized with the collection of air samples from two air inlets at different heights on the tower. The coordination of the sampling and the subsequent analysis of the tower air are conducted by our collaborators in the Climate Chemistry Measurements and Research Division (CRD) of Environment Canada’s Atmospheric Science and Technology Directorate. Sample collection began in October 2005. Flights are conducted by Transwest Air out of Prince Albert, Saskatchewan.

FAAM Aircraft (FAM)

-99.9999 °N | 999.9999 °W | -9999.99 m

  • First Sample Date: 2014-07-09
  • Last Sample Date: 2015-05-12
  • Top Altitude: 2000 m/6561 ft
  • Bottom Altitude: 129 m/423 ft
  • Average Flight Frequency: Every 38 days
  • Aircraft:
  • Status: Terminated
  • Data Visualization

Fortaleza (FTL)

-3.5200 °N | 38.28 °W | 3.00 m

  • First Sample Date: 2000-12-09
  • Last Sample Date: 2003-03-25
  • Top Altitude: 4267 m/13999 ft
  • Bottom Altitude: 152 m/498 ft
  • Average Flight Frequency: Every 85 days
  • Aircraft:
  • Status: Terminated
  • Data Visualization
Plane used at FTL
Sample Inlet on FTL plane

Fairchild, Wisconsin (FWI)

44.6600 °N | 90.96 °W | 334.30 m

  • First Sample Date: 2004-09-20
  • Last Sample Date: 2005-11-18
  • Top Altitude: 8073 m/26486 ft
  • Bottom Altitude: 590 m/1935 ft
  • Average Flight Frequency: Every 14 days
  • Aircraft: Cessna 421B
  • Status: Terminated
  • Data Visualization
Plane used at FWI
Sample Inlet on FWI plane
Samples were collected over mixed agricultural and forested land near Fairchild in west central Wisconsin. Sample collection at FWI started in September 2004, but the site was discontinued in November 2005 because of funding cuts. Flights were conducted by Jeff Smalley and Dr. Dirk Brom of Hap’s Air Service based in Ames, Iowa.

National Observations of Greenhouse Gases using Aircraft Profiles (NOGAP) (GAP)

-99.9999 °N | 999.9999 °W | -9999.99 m

  • First Sample Date: 2024-02-05
  • Last Sample Date: 2025-03-09
  • Top Altitude: 6553 m/21499 ft
  • Bottom Altitude: 123 m/403 ft
  • Average Flight Frequency: Every 5 days
  • Aircraft:
  • Status: Ongoing
  • Data Visualization

Molokai Island, Hawaii (HAA)

21.2300 °N | 158.95 °W | 3.00 m

  • First Sample Date: 1999-05-31
  • Last Sample Date: 2008-04-22
  • Top Altitude: 8104 m/26587 ft
  • Bottom Altitude: 4 m/13 ft
  • Average Flight Frequency: Every 16 days
  • Aircraft: Cessna 421
  • Status: Terminated
  • Data Visualization
Plane used at HAA
Sample Inlet on HAA plane
Samples were collected over the Pacific Ocean west of Honolulu, Hawaii. In addition to providing a vertical profile of carbon cycle gas measurements in this area, HAA samples were also used to help calibrate the Measurement Of Pollution In The Troposphere (MOPITT) instrument flown aboard NASA's Earth System Enterprise (ESE) Terra satellite. Sample collection at HAA started in May 1999, but the site was discontinued in April 2008 because of funding cuts.

Harvard Forest, Massachusetts (HFM)

42.5378 °N | 72.1714 °W | 340.00 m

  • First Sample Date: 1999-11-11
  • Last Sample Date: 2007-11-18
  • Top Altitude: 8063 m/26453 ft
  • Bottom Altitude: 582 m/1909 ft
  • Average Flight Frequency: Every 18 days
  • Aircraft: Cessna TU206
  • Status: Terminated
  • Data Visualization
Plane used at HFM
Sample Inlet on HFM plane
Samples were collected over the forest lands of Harvard Forest in north central Massachusetts. In addition to providing a vertical profile of carbon cycle gas measurements in this area, HFM samples were also used to help calibrate the Measurement Of Pollution In The Troposphere (MOPITT) instrument flown aboard NASA's Earth System Enterprise (ESE) Terra satellite. Sample collection at HFM started in November 1999, but the site was discontinued in December 2007 because of funding cuts. These flights were conducted by Dick Hordom of Four Star Aviation.

Homer, Illinois (HIL)

40.0700 °N | 87.91 °W | 201.50 m

  • First Sample Date: 2004-09-16
  • Last Sample Date: 2025-03-20
  • Top Altitude: 8117 m/26630 ft
  • Bottom Altitude: 322 m/1056 ft
  • Average Flight Frequency: Every 14 days
  • Aircraft: Piper PA 34-220T
  • Status: Ongoing
  • Data Visualization
Plane used at HIL
Sample Inlet on HIL plane
Samples are collected over relatively flat, agricultural land near Homer in east central Illinois. Sample collection at HIL started in September 2004.

Howland, Maine (HOW)

42.2000 °N | 68.13 °W | -9999.99 m

  • First Sample Date: 1996-12-21
  • Last Sample Date: 1997-06-23
  • Top Altitude: 3048 m/10000 ft
  • Bottom Altitude: 122 m/400 ft
  • Average Flight Frequency: Every 184 days
  • Aircraft:
  • Status: Terminated
  • Data Visualization

INFLUX (Indianapolis Flux Experiment) (INX)

39.5805 °N | 86.4207 °W | -9999.99 m

  • First Sample Date: 2010-10-27
  • Last Sample Date: 2016-05-19
  • Top Altitude: 3518 m/11541 ft
  • Bottom Altitude: 302 m/990 ft
  • Average Flight Frequency: Every 33 days
  • Aircraft: Beechcraft
  • Status: Terminated
  • Data Visualization
Plane used at INX

Park Falls, Wisconsin (LEF)

45.9451 °N | 90.2732 °W | 472.00 m

  • First Sample Date: 1998-04-10
  • Last Sample Date: 2025-04-08
  • Top Altitude: 5060 m/16601 ft
  • Bottom Altitude: 537 m/1761 ft
  • Average Flight Frequency: Every 19 days
  • Aircraft: Cessna 172
  • Status: Ongoing
  • Data Visualization
Plane used at LEF
Sample Inlet on LEF plane
Samples are collected over forest land near Park Falls in north central Wisconsin. Flights are conducted over a tall communications tower that also houses air sampling equipment. Air samples are collected at the surface as well as from the tower. Sample collection via aircraft at LEF began in April 1998.

Offshore Portsmouth, New Hampshire (Isles of Shoals) (NHA)

42.9500 °N | 70.63 °W | 0.00 m

  • First Sample Date: 2003-09-12
  • Last Sample Date: 2025-04-09
  • Top Altitude: 8136 m/26692 ft
  • Bottom Altitude: 0 m/0 ft
  • Average Flight Frequency: Every 14 days
  • Aircraft: Cessna T210
  • Status: Ongoing
  • Data Visualization
Plane used at NHA
Sample Inlet on NHA plane
Samples are collected over the Atlantic Ocean off the coast of New Hampshire and just south of the Isle of Shoals. Sample collection at NHA started in September 2003.

Northern Saskatchewan (NSK)

58.7300 °N | 104.9 °W | 401.00 m

  • First Sample Date: 2020-12-26
  • Last Sample Date: 2021-02-13
  • Top Altitude: 6799 m/22306 ft
  • Bottom Altitude: 820 m/2690 ft
  • Average Flight Frequency: Every 24 days
  • Aircraft:
  • Status: Terminated
  • Data Visualization

Oglesby, Illinois (OIL)

41.2800 °N | 88.94 °W | 192.60 m

  • First Sample Date: 2004-09-16
  • Last Sample Date: 2005-11-19
  • Top Altitude: 8121 m/26643 ft
  • Bottom Altitude: 530 m/1738 ft
  • Average Flight Frequency: Every 12 days
  • Aircraft: Piper PA 31-325
  • Status: Terminated
  • Data Visualization
Plane used at OIL
Sample Inlet on OIL plane
Samples were collected over flat, agricultural land near Oglesby in central Illinois. Sample collection at OIL started in September 2004, but the site was discontinued in November 2005 because of funding cuts.

Poker Flat, Alaska (PFA)

64.9000 °N | 148.76 °W | 210.00 m

  • First Sample Date: 1999-06-27
  • Last Sample Date: 2025-03-19
  • Top Altitude: 7618 m/24993 ft
  • Bottom Altitude: 131 m/429 ft
  • Average Flight Frequency: Every 13 days
  • Aircraft: Piper PA 31-325
  • Status: Ongoing
  • Data Visualization
Plane used at PFA
Sample Inlet on PFA plane
Samples are collected over the forest land of Poker Flat Research Range northeast of Fairbanks, Alaska. In addition to providing a vertical profile of carbon cycle gas measurements in this area, PFA samples were also used to help calibrate the Measurement Of Pollution In The Troposphere (MOPITT) instrument flown aboard NASA's Earth System Enterprise (ESE) Terra satellite. Sample collection at PFA started in June 1999.

Rarotonga (RTA)

-21.2500 °N | 159.83 °W | 3.00 m

  • First Sample Date: 2000-04-16
  • Last Sample Date: 2025-04-08
  • Top Altitude: 6528 m/21417 ft
  • Bottom Altitude: 13 m/42 ft
  • Average Flight Frequency: Every 18 days
  • Aircraft: Embraer Bandeirante 110
  • Status: Ongoing
  • Data Visualization
Plane used at RTA
Sample Inlet on RTA plane
Samples are collected over the South Pacific near Rarotonga in the Cook Islands. In addition to providing a vertical profile of carbon cycle gas measurements in this area, RTA samples were also used to help calibrate the Measurement Of Pollution In The Troposphere (MOPITT) instrument flown aboard NASA's Earth System Enterprise (ESE) Terra satellite. This is a unique site because these are currently the only CCGG network vertical profiles being measured in the Southern Hemisphere. Sample collection at RTA started in April 2000. Flights are conducted by Alistair Macquarie & crews from Air Rarotonga.

Santarem (SAN)

-2.8500 °N | 54.95 °W | 78.00 m

  • First Sample Date: 2000-12-07
  • Last Sample Date: 2003-08-20
  • Top Altitude: 5200 m/17060 ft
  • Bottom Altitude: 300 m/984 ft
  • Average Flight Frequency: Every 73 days
  • Aircraft:
  • Status: Terminated
  • Data Visualization
Plane used at SAN
Sample Inlet on SAN plane

Offshore Charleston, South Carolina (SCA)

32.7700 °N | 79.55 °W | 0.00 m

  • First Sample Date: 2003-08-22
  • Last Sample Date: 2025-04-17
  • Top Altitude: 13279 m/43566 ft
  • Bottom Altitude: 218 m/715 ft
  • Average Flight Frequency: Every 26 days
  • Aircraft: Cessna 337C Turbo
  • Status: Ongoing
  • Data Visualization
Plane used at SCA
Sample Inlet on SCA plane
Samples are collected over the Atlantic Ocean off the coast of Charleston, South Carolina. Sample collection at SCA started in August 2003.

Southern Great Plains, Oklahoma (SGP)

36.6070 °N | 97.489 °W | 314.00 m

  • First Sample Date: 1998-03-02
  • Last Sample Date: 2025-03-26
  • Top Altitude: 12949 m/42483 ft
  • Bottom Altitude: 152 m/498 ft
  • Average Flight Frequency: Every 13 days
  • Aircraft: Cessna 337C Turbo
  • Status: Ongoing
  • Data Visualization
Plane used at SGP
Sample Inlet on SGP plane
Samples are collected over relatively flat, agricultural land of the Southern Great Plains region of north central Oklahoma. Sampling is conducted in collaboration with Lawrence Berkeley National Laboratory and the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Program / Cloud and Radiation Testbed. Limited sample collection via aircraft at SGP started in September 2002 using a modified manual sampling method. Sample collection with the current programmable flask packages at SGP started in March 2006.

Offshore Corpus Christi, Texas (TGC)

27.7300 °N | 96.86 °W | 0.00 m

  • First Sample Date: 2003-09-09
  • Last Sample Date: 2025-03-20
  • Top Altitude: 8255 m/27083 ft
  • Bottom Altitude: 19 m/62 ft
  • Average Flight Frequency: Every 15 days
  • Aircraft: Cessna 421B
  • Status: Ongoing
  • Data Visualization
Plane used at TGC
Sample Inlet on TGC plane
Samples are collected over the Gulf of America (formerly the Gulf of Mexico) off the coast of Corpus Christi, Texas. Sample collection started at TGC in September 2003.

Trinidad Head, California (THD)

41.0541 °N | 124.151 °W | 107.00 m

  • First Sample Date: 2003-09-02
  • Last Sample Date: 2025-03-29
  • Top Altitude: 8131 m/26676 ft
  • Bottom Altitude: 152 m/498 ft
  • Average Flight Frequency: Every 16 days
  • Aircraft: Mooney M20M
  • Status: Ongoing
  • Data Visualization
Plane used at THD
Sample Inlet on THD plane
Samples are collected over the Pacific Ocean off the coast of Trinidad Head, California. Sample collection started at THD in September 2003.

Kajjansi Airfield, Kampala, Uganda (UGD)

0.2000 °N | 32.55 °E | 1141.00 m

  • First Sample Date: 2020-12-15
  • Last Sample Date: 2022-06-22
  • Top Altitude: m/0 ft
  • Bottom Altitude: m/0 ft
  • Average Flight Frequency: Not available
  • Aircraft:
  • Status: Terminated
  • Data Visualization

Ulaanbaatar (ULB)

47.4000 °N | 106 °E | 1350.00 m

  • First Sample Date: 2004-03-25
  • Last Sample Date: 2009-03-05
  • Top Altitude: 5944 m/19501 ft
  • Bottom Altitude: 1512 m/4960 ft
  • Average Flight Frequency: Every 33 days
  • Aircraft: Cessna 208
  • Status: Terminated
  • Data Visualization
Plane used at ULB
Sample Inlet on ULB plane
Samples were collected over the forested mountains of central Mongolia, southwest of the capital Ulaanbaatar. These flights were conducted in collaboration with the Mongolian Hydrometeorological Research Institute. Sample collection at ULB started in March 2004, but the site was discontinued in March 2009 because of funding cuts.

West Branch, Iowa (WBI)

41.7248 °N | 91.3529 °W | 241.70 m

  • First Sample Date: 2004-09-14
  • Last Sample Date: 2025-03-28
  • Top Altitude: 8204 m/26916 ft
  • Bottom Altitude: 543 m/1781 ft
  • Average Flight Frequency: Every 14 days
  • Aircraft: Cessna 421B
  • Status: Ongoing
  • Data Visualization
Plane used at WBI
Sample Inlet on WBI plane
Samples are collected over flat agricultural land near West Branch in east central Iowa. Flights are conducted over a tall communications tower that also houses air sampling equipment. Sample collection via aircraft began in September 2004, originally over Rawley, Iowa (RIA), approximately 90 km to the northwest of the current site. The aircraft sampling was relocated to WBI in January 2008 to coordinate with air sample collection and monitoring at the WBI tower. Flights are conducted by Jeff Smalley and Dr. Dirk Brom of Hap’s Air Service based in Ames, Iowa.

Walnut Grove, California (WGC)

38.2645 °N | 121.4904 °W | 2.00 m

  • First Sample Date: 2008-05-23
  • Last Sample Date: 2009-03-08
  • Top Altitude: 3177 m/10423 ft
  • Bottom Altitude: 6 m/19 ft
  • Average Flight Frequency: Every 19 days
  • Aircraft:
  • Status: Terminated
  • Data Visualization
Plane used at WGC
Sample Inlet on WGC plane