| OPERATIONAL SITES |
| UNAM, Mexico | 19 N, 99 W | PI: Anne Thompson (Penn State) |
| Barbados | 13.2 N, 59.5 W | PI: Sam Oltmans (NOAA/ESRL/GMD) |
| R/V/ Ron Brown | Gulf of Mexico | PI: Daniel Wolfe (NOAA) |
| Canada |
| Kelowna, British Columbia | 49.9 N, 119.4 W | PI: David Tarasick (Environment Canada) |
| Stonyplain, Alberta | 53.6 N, 114.1 W | PI: David Tarasick (Environment Canada) |
| Bratt's Lake, Saskatchewan | 50.2 N, 104.7 W | PI: David Tarasick (Environment Canada) |
| Egbert, Ontario | 44.2 N, 79.8 W | PI: David Tarasick (Environment Canada) |
| Sable Is., Nova Scotia | 44.0 N, 60.0 W | PI: David Tarasick (Environment Canada) |
| Walsingham, Ontario | 42.6 N, 80.6 W | PI: Trevor Carey-Smith (Environment Canada) |
| Yarmouth, Nova Scotia | 43.9 N, 66.1 W | PI: David Tarasick (Environment Canada) |
| USA |
| Beltsville, Maryland | 39.0 N, 76.5 W | PI: Everette Joseph (Howard University)
Bojan Bojkov (UMBC at NASA/GSFC)
David Whiteman (NASA/GSFC) |
| Boulder, Colorado | 40.3 N, 105.2 W | PI: Samuel Oltmans (NOAA/ESRL/GMD) |
| Richland, Washington | 46.0 N, 119.0 W | PI: Anne Thompson (Penn State) |
| Holtville, California | 32.8 N, 115.4 W | PI: Robert Chatfield (NASA/Ames) |
| Houston, Texas | 29.7 N, 95.4 W | PI: Gary Morris (Valparaiso Univ.) |
| Huntsville, Alabama | 35.3 N, 86.6 W | PI: Mike Newchurch (Univ. Alabama - Huntsville) |
| Socorro, New Mexico | 36.4N, 106.9W | PI: Mavendra K Dubey (Los Alamos Nat. Lab.) |
| Paradox, New York | 43.9 N, 73.6 W | PI: Shermane Austin (Medger Evers, CUNY) |
| Table Mountain, California | 34.4 N, 117.7 W | PI: Thierry Leblanc (NASA/JPL) |
| Narragansett, Rhode Is. | 41.5 N, 71.4 W | PI: John Merrill (Univ. Rhode Is.) |
| Trinidad Head, Calfornia | 40.8 N, 124.2 W | PI: Samuel Oltmans (NOAA/ESRL/GMD) |
| Valparaiso, Indiana | 41.5 N, 87.0 W | PI: Gary Morris (Valparaiso Univ.) |
| Wallops Is, Virginia | 37.9 N, 75.5 W | PI: Frank Schmidlin (NASA/WFF) |
