NWT RESEARCH DATABASE

Regions: North Slave Region

Tags: physical sciences, greenhouse gases, atmospheric sciences

Objective(s): To conduct high quality ground-based atmospheric measurements of carbon dioxide, methane and other greenhouse gases from coastal, interior and Arctic regions in Canada.

Project Description: Environment Canada’s (EC) Greenhouse Gases (GHGs) Measurement Program conducts high quality ground-based atmospheric measurements of carbon dioxide (CO2) and methane (CH4) and other GHGs from coastal, interior and Arctic regions in Canada. The goal is to provide high quality data to put observational constraints on large-scale sources and sinks, and improve understanding of the carbon cycle. The long lifetime and rapid mixing of CO2 and CH4 in the atmosphere provides a large scale integration of surface fluxes. With sufficient measurement precision and surface coverage (measurement sites), a signature of individual surface source or sink regions can be detected and quantified. The GHG measurement program is maintained by the Climate Chemistry Measurements and Research (CCMR) section at Environment Canada. The simultaneous measurement of atmospheric CO2 and CH4 is made possible by using a Picarro G1301 gas analyzer. The measurement technology, based on cavity ring down detection, is new to the measurement community engaged in precise and accurate GHG measurements. A small pump, located inside the observatory (and at the back of the analyzer), is used to supply ambient air to the Picarro unit from the top of a 200 foot tower. Located upstream of the sample pump, the ambient air stream passes through a 7 micron stainless steel membrane. The ambient air then passes through a pressure relief valve set at ~1 atmosphere to release excess pressure (and minimize the air residence time in the sampling tube). The ambient air is then dried to a dew point of around -30 degrees Celsius by passing it through a dual channel Peltier cooler (Model MC 30). Two 30 litre aluminum standard tanks equipped with high-purity, two-stage gas regulators are used as gas standards. The lifetime of these station standards are expected to be two years and will be changed by CCMR staff during scheduled annual maintenance visits. Stainless steel tubing is used for the standard gas sample lines and for the ambient sample line after the cold trap. Selection of ambient sample or standard tank gas is performed by electrical actuation of a 1/16” 8-port stream selection valve. All flow rates are maintained around 400 ml/min using an electronic flow controller. All data is posted on the World Meteorological Organizations GHG data centre maintained by the Japanese Meteorological Agency in Tokyo, Japan. Web site: http://gaw.kishou.go.jp/wdcgg/ The fieldwork for this study will be conducted from January 1, 2011 to December 31, 2011.