High-quality eddy-covariance CO2 budgets under cold climate conditions

摘要: This study aimed at quantifying potential negative effects of instrument heating to improve eddy covariance flux data quality in cold environments. Our overarching objective was minimize heating-related bias annual CO2 budgets from an Arctic permafrost system. We used continuous eddy-covariance measurements covering three full years within ecosystem with parallel sonic anemometers operation activated and without as well open- closed-path gas analyzers, the latter serving a reference. Our results demonstrate that anemometer has direct effect on temperature while turbulent wind field is not affected. As consequence, fluxes sensible heat are increased by average 5 W m-2 heating, no other scalar observed. However, biased can have indirect case they input for density-flux WPL correction open-path analyzer. Evaluating self-heating analyzer comparing between analyzers we found systematically higher uptake recorded sensor, leading cumulative offset 96 gC m-2, which only result winter season but also due substantial during summer. With inclined sensor mounting, fraction vertically mounted instruments required.