Soil respiration–driven CO2 pulses dominate Australia’s flux variability
Eva-Marie Metz
Eva-Marie Metz (Schömann)
INF 229, SR 108/110

The semi-arid Australian continent significantly influences the interannual variability of the global terrestrial carbon sink. However, current estimates of the Australian carbon fluxes show large uncertainties due to the sparsity of used in-situ measurements. Satellite CO2 measurements offer an independent and spatially extensive source of information about the Australian carbon cycle.

In my talk, I will present our new publication about the Australian carbon cycle. In our study, we examine the decadal data set (2009-2018) of atmospheric CO2 concentrations delivered by the Greenhouse Gases Observing Satellite (GOSAT). We find previously undetected atmospheric CO2 pulses reoccurring annually at the end of the dry season. These pulses largely control the interannual variability of Australia’s CO2 fluxes. They are driven by soil respiration due to rewetting of the soils in Australia’s semiarid regions. The suggested continental-scale relevance of soil-rewetting processes has substantial implications for our understanding and modeling of global climate–carbon cycle feedbacks.