Alert is the most northerly site in the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Network. It is located on the northeastern tip of Ellesmere Island in Nunavut, far removed from the major industrial regions of the Northern Hemisphere.
Alert is also the site of a military station (CFS Alert) staffed with around 60 personnel, and a MSC Upper Air Weather Station. The air chemistry observatory is located on a plateau about 6 km SSW of the main camp. The plateau rises abruptly to an elevation of about 200 m (with local hills rising to 500 m). The plateau forms the northern edge of the Hazen Plateau, which continues to rise to the south, reaching a typical elevation of 1000 m and extending through the central part of northern Ellesmere Island. The southeastern edge of the Hazen Plateau is defined by the 7500 km2 Agassiz Ice Cap, a permanent feature with a central elevation greater than 2000 m.
Southwest of Alert is the rugged United States range, with peaks exceeding 2500 m. The Greenland coast is 60 km east of Alert. The terrain in the immediate area of Alert is steeply rolling, on the order of 100-150 m above sea level, with frequent deep ravines and high cliffs. The land is covered with snow for almost ten months of the year. During the summer, the land is covered with a sparse covering of polar desert vegetation. Alert experiences 106 days of full darkness (October 30th to February 13th), 153 days of 24-hour daylight (April 7th to September 7th), and two 53-day transition periods with some diurnal cycle going from virtually total daylight to total darkness (and vice-versa).
The annual mean air temperature at the Observatory is -18°C and the monthly mean air temperature increases to 3°C in August and decreases to below -30°C from December to the end of March. The annual mean value of the wind velocity is 3.5 m s-1. The prevailing winds are SSE to WWS due to channelling by the mountainous regions of northern Ellesmere Island and Greenland. A more detailed meterological summary can be found in Hopper and Hart .
Hopper, J.F. and W. Hart .Meteorological aspects of the 1992 Polar Sunrise Experiment, Journal of Geophysical Research, 99, (D12), 25315-25328, 1994.
|Parameter||Formula||First Sample Date||Status||Carbon Dioxide||CO2||1985-06-10||Ongoing||Methane||CH4||1985-06-10||Ongoing||Carbon Monoxide||CO||1990-10-05||Ongoing||Molecular Hydrogen||H2||1990-10-05||Ongoing||Nitrous Oxide||N2O||1995-11-03||Ongoing||Sulfur Hexafluoride||SF6||1995-11-03||Ongoing||Carbon-13/Carbon-12 in Carbon Dioxide||d13C (CO2)||1992-04-30||Ongoing||Oxygen-18/Oxygen-16 in Carbon Dioxide||d18O (CO2)||1992-04-30||Ongoing||Carbon-13/Carbon-12 in Methane||d13C (CH4)||2000-08-11||Ongoing||D/H in Methane||dD (CH4)||2005-04-20||Terminated - 2009-10-28||Methyl Chloride||CH3Cl||2005-09-07||Ongoing||Benzene||C6H6||2006-11-09||Ongoing||toluene||C7H8||2006-11-09||Ongoing||ethane||C2H6||2005-09-07||Ongoing||ethene||C2H4||2005-09-07||Ongoing||propane||C3H8||2005-09-07||Ongoing||propene||C3H6||2005-09-07||Ongoing||i-butane||i-C4H10||2005-09-07||Ongoing||n-butane||n-C4H10||2005-09-07||Ongoing||i-pentane||i-C5H12||2005-09-07||Ongoing||n-pentane||n-C5H12||2005-09-07||Ongoing||n-hexane||n-C6H14||2005-09-07||Ongoing||Wind Speed||ws||1992-07-03||Ongoing||Wind Direction||wd||1992-07-03||Ongoing||Temperature||temp||2004-08-05||Terminated - 2004-08-26||isoprene||C5H8||2006-11-09||Ongoing||Acetylene||C2H2||2010-01-07||Ongoing|
HATS Flask Sampling
|Parameter||Formula||First Sample Date||Status||HFC-134a||CH2FCF3||1994-12-08||Ongoing||HCFC-22||CHF2Cl||1992-01-20||Ongoing||Methyl Chloride||CH3Cl||1993-12-30||Ongoing||HCFC-142b||CH3CF2Cl||1992-01-20||Ongoing||Halon-1211||CBrClF2||1992-01-20||Ongoing||methyl bromide||CH3Br||1992-11-28||Ongoing||HCFC-141b||CH3CCl2F||1993-02-11||Ongoing||CFC-113||CCl2FCClF2||1992-01-20||Ongoing||dichloromethane||CH2Cl2||1994-05-12||Ongoing||tetrachloroethylene||C2Cl4||1993-11-18||Ongoing||carbonyl sulfide||COS||2000-05-18||Ongoing||HFC-152a||CH3CHF2||2000-07-06||Ongoing||Halon 2402||CBrF2CBrF2||1995-02-16||Ongoing||HFC-227ea||CF3CHFCF3||2011-05-04||Ongoing||HFC-365mfc||CH3CF2CH2CF3||2009-07-22||Ongoing||Methyl Chloroform||CH3CCl3||1991-11-15||Ongoing|
Aerosol Surface In-Situ
Radiation In-Situ Observatory
|Parameter||Formula||First Sample Date||Status||Direct Beam||2004-08-13||Ongoing||Shortwave Global||2004-08-13||Ongoing||Diffuse||2004-08-13||Ongoing||Reflected Shortwave||2004-08-13||Ongoing||Downward Longwave||2004-08-13||Ongoing||Upward Longwave||2004-08-13||Ongoing|
Baseline Surface Radiation Network