Unforced interannual-to-decadal variability of global radiation imbalance: Role of low clouds
Miyamoto, A., Xie, S., Deser, C.. (2026). Unforced interannual-to-decadal variability of global radiation imbalance: Role of low clouds. Journal of Climate, doi:https://doi.org/10.1175/jcli-d-25-0320.1
| Title | Unforced interannual-to-decadal variability of global radiation imbalance: Role of low clouds |
|---|---|
| Genre | Article |
| Author(s) | A. Miyamoto, S. Xie, Clara Deser |
| Abstract | The global-mean radiation imbalance at the top of the atmosphere (GMTOA) is an important indicator of the climate response to anthropogenic greenhouse forcing. Natural variability perturbs this radiation imbalance on interannual and decadal time scales, confounding the externally forced signal. However, limited observations hinder efforts to understand the mechanisms of internally generated radiation imbalance. This study investigates the natural variability of global TOA radiation using a 500-yr preindustrial coupled simulation with the Community Earth System Model, version 2, and a corresponding atmospheric model simulation forced with daily sea surface temperature (SST) and sea ice from the coupled run. GMTOA variations lead those in tropical Pacific SST and global-mean surface temperature by 90° in phase and are attributed to time-scale-dependent SST patterns and associated low cloud radiative effects. Interannual GMTOA peaks are driven by the development and decay of El Niño–Southern Oscillation (ENSO), which induce low cloud anomalies that are maximized over the equatorial northeast Pacific. In contrast, decadal GMTOA variability stems from variations in eastern subtropical low cloud decks coupled with underlying SST anomalies. These low cloud–SST covariations are triggered by stochastic extratropical atmospheric variability. This time-scale dependence reflects the characteristics of these drivers: The amplitude of ENSO peaks at interannual time scales due to tropical ocean dynamics, whereas extratropical stochastic forcing on SST becomes increasingly important on decadal and longer time scales. Recent satellite observations of GMTOA corroborate both mechanisms. This study underscores the importance of subtropical low cloud–SST covariations driven by extratropical atmospheric forcing in unforced variability of global energy imbalance. |
| Publication Title | Journal of Climate |
| Publication Date | Mar 1, 2026 |
| Publisher's Version of Record | https://doi.org/10.1175/jcli-d-25-0320.1 |
| OpenSky Citable URL | https://n2t.net/ark:/85065/d79p367k |
| OpenSky Listing | View on OpenSky |
| CGD Affiliations | CAS |