A comprehensive examination of global atmospheric CO2 teleconnections using wavelet-based multi-resolution analysis

Abstract

Interannual variability of the atmospheric CO2 accumulation is at a similar magnitude of decadal average CO2 accumulation in the atmosphere. Part of observed variability in the atmospheric CO2 can be interpreted by large-scale climate variability. Teleconnection between the atmospheric CO2 anomalous tendency and selected large-scale coupled oceanic and atmospheric oscillations (AO, NAO, PDO, IOD, ENSO and SAM) are examined using wavelet-based multi-resolution analysis. The results indicate that all six oscillation indices appear to be associated with monthly CO2 concentration at most of the 13 examined stations. About 70 % of interannual variability of CO2 anomalous tendency at Mauna Loa and South Pole can be interpreted by the climatic indices. The temperature effects on the CO2 anomalous tendency are overall positive. At the monthly scale, they interpret 14 % variability in CO2 anomalous tendency in 1980–2011. At two high elevation stations (Mauna Loa and South Pole) with large footprints, the teleconnection signal is stronger (interpreting 20 and 25 % variability in monthly CO2 anomalous tendency, respectively). Including global mean monthly air temperature time series, slightly but significantly in the statistical sense, improves the proportion of monthly CO2 anomalous tendency being interpreted at most of the examined stations. The signs (positive vs. negative) in the association between monthly CO2 anomalous tendency and the significant climatic indices appear to reflect physical mechanisms leading to such teleconnections.