High Levels of CO₂ Exchange During Synoptic‐Scale Events Introduce Large Uncertainty Into the Arctic Carbon Budget

Abstract

Abstract CO 2 release from thawing permafrost is both a consequence of, and a driver for, global warming, making accurate information on the Arctic carbon cycle essential for climate predictions. Eddy covariance data obtained from Bayelva (Svalbard) in 2015, using well‐established processing and quality control techniques, indicate that most of the annual net CO 2 uptake is due to high CO 2 flux events in winter that are associated with strong winds and probably relate to technical limitations of the gas analyzer. Emission events may relate to either (unidentified) instrumental limitations or to physical processes such as CO 2 advection. Excluding the high winter uptake events yields an annual CO 2 budget close to zero; whether or not these events are included can, therefore, have a considerable effect on carbon budget calculations. Further investigation will be crucial to pinpoint the factors causing these high CO 2 flux events and to derive scientifically substantiated flux processing standards.