Performance evaluation of an integrated eddy covariance system in a cold environment

Sensor self-heating is known to degrade the quality of the CO2 flux measured with open-path eddy covariance. The problem arises from the density correction algorithm that uses the temperature fluctuations measured outside the optical-path of its gas analyzer. In this study, we compared an integrated open-path eddy covariance system (IRGASON, Campbell Scientific, Inc., USA.) with an open-path system consisting of a sonic anemometer (Gill Windmaster Pro, Gill Instruments Ltd, UK) and a gas analyzer (LI7500A, LI-COR, Inc, USA). One advantage of IRGASON is that its sonic temperature is measured in the optical path of the gas analyzer and as such the sensor self-heating problem should be minimal. In this paper we report the results of a field inter-comparison experiment conducted at a populus euphratica plantation forest (88°01'E, 40°26'N) near Yuli Country, Xinjiang Province, China in the winter of 2013-2014. Additional tests are planned for the spring of 2014 at the Lake Taihu Eddy Flux Mesonet sites in southeastern China.