Coupled budgets of the climate system
The energy budget probably is the most fundamental approach to quantify global climate. Flows of energy through the climate system involve all compartments: atmosphere, ocean, land, and cryosphere. While lateral transports mainly occur in atmosphere and ocean, all compartments play a role in storing energy on various time scales. Moreover, many process and phenomena involve strong coupling between components. A prominent example is El Nino – Southern Oscillation (ENSO), which not only exhibits strongly coupled atmosphere-ocean dynamics, but also involves massive energy exchanges between atmosphere and ocean (Figure top right).
A complete picture of Earth’s energy cycle in terms of mean, variability, and change can only be achieved when taking a coupled perspective. This ideally combines the most credible observationally constrained data sets using optimal evaluation methods. The latter not only involves advanced numerical methods, but also diagnostic frameworks that are consistent across compartments, e.g. in terms of treatment of energy carried by water when moving between compartments. Applications of coupled budgets are two-fold: on the one hand, they aim to obtain optimal budget closure, e.g. via variational methods, to enable physically consistent assessments while on the other hand residuals arising when combining independent data sets to estimate the full energy budget can provide valuable feedback to the data providers.
Our group works on various aspects associated with coupled energy budgets. We continuously work on improving methods and diagnostic frameworks, which also involves evaluation energy budget aspects of reanalysis products and provision of state-of-the-art atmospheric energy budget data (CDS). We are involved with various international activities (e.g., WCRP EPESC) investigating aspects of Earth’s Energy Imbalance (EEI), such as precise quantification of the atmosphere’s contribution to EEI (Figure bottom right). Furthermore, we have a strong interest in studies that link the energy budget with climate dynamics and anomalies, e.g. by diagnosing ENSO energetics in a coupled framework. Polar energy budgets are another aspect of our coupled budget work, which is described here.
Researchers:
- Michael Mayer
- Leopold Haimberger
- Susanna Winkelbauer
- Hamish Prince
Projects:
Maps of ocean heat content changes (ΔOHC, in Zettajoules ZJ) and associated anomalous heat exchanges during two strong El Nino events 1997/98 and 2015/16. Arrows indicate direction of anomalous heat transports and fluxes across the boundaries of the tropical Pacific (numbers in ZJ). Integrated OHC changes are given for 0-300m and full-depth ocean (in brackets). Signs are chosen that positive (negative) values indicate a contribution to a warming (cooling) of the Pacific. Note the marked differences in anomalous air-sea fluxes and oceanic heat transports through Indonesian Throughflow which explain much of the different OHC evolution during the two El Nino events. Edited from Mayer et al. (2018; doi.org/10.1002/2018GL077106).
a) Global mean time series of net top-of-atmosphere (TOA) irradiance anomalies as measured by CERES satellite instruments (reflecting variations in EEI), ocean heat content change from the RFROM product, and the sum of heat uptake/storage change in ocean, atmosphere, sea ice, and land. Panel (b) shows storage changes in land, sea ice, and atmosphere separately together with the Niño 3.4 (N3.4) ENSO index (thin gray line) to highlight its strong link with atmospheric storage change. Adding atmospheric, land, and sea ice contributions to oceanic heat uptake substantially improves the agreement with net irradiance at TOA (see panel a), as expected from energy conservation. The improved agreement is particularly notable after 2022, because of the substantial atmospheric warming in 2023. During that time period the ocean heat uptake anomaly explains less than half of the TOA anomaly. Edited from Mayer et al. (2026; doi.org/10.1029/2025GL119833)