Non-linear effects of SST anomalies on atmospheric circulations

9 September 2025

Photo: YBZhao

Local precipitation rate changes (Δ𝑃𝑟, in mm day−1) as a function of the local background sea-surface temperature (SST, in ◦C). Colours indicate the latitude location of the SST anomaly. A linear fit is applied for SST values below 25◦C.

A paper by Yuan-Bing Zhao and colleagues, recently published in the Journal of Climate, systematically investigates the atmospheric circulation response to regional sea surface temperature (SST) anomalies across the global oceans. Such anomalies may arise from climate change or from systematic errors in climate models (model biases). The study shows that the response is strongly influenced by the background SST. Nonlinear responses occur when the background SST exceeds approximately 25 °C, such that a +1.5 °C anomaly pushes conditions beyond the threshold for intense atmospheric convection. These findings highlight the critical importance of accurately representing background SSTs in the tropical Indian Ocean and western Pacific for reliable climate simulations. Details and further results: https://doi.org/10.1175/JCLI-D-24-0328.1

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More information

Publication
Zhao, Y., F. Lunkeit, and N. Žagar, 2025: Sensitivity of Stationary Wave Response to the Position of Sea Surface Temperature Anomalies during Boreal Winter. J. Climate, 38, 5179–5200, https://doi.org/10.1175/JCLI-D-24-0328.1

DFG-funded project TRR181

Contact
Frank Lunkeit
Universität Hamburg
CEN – Center for Earth System Research and Sustainability
Telefon: +49 40 42838-5073
Email: frank.lunkeit@uni-hamburg.de