资源环境科技发展态势分析平台

We contrast the spatial patterns of tropical climate response to localized thermal forcing over different ocean basins in an atmospheric model coupled to a slab ocean. A localized forcing poleward of the climatological storm tracks produces a tropical climate response pattern that is nearly independent of the forcing location. Regardless of the location of extratropical forcing, a common zonally asymmetric La Nina-like pattern of sea surface temperature response accompanies a northward shift of the Intertropical Convergence Zone. In contrast, a localized tropical forcing produces essentially opposite tropical climate response patterns depending on the forced ocean basin. The northern tropical Pacific (Atlantic) heating induces a warming (cooling) throughout the tropical Pacific, a weakening (strengthening) of the equatorial Pacific trade winds, and a northward (southward) shift of the Southern Pacific Convergence Zone. Our study provides a pathway forward for improving future projections of tropical climate under different anthropogenic forcing scenarios.

Plain Language Summary One of the frontline challenges in climate dynamics is understanding the dynamics of basin-to-basin and tropical-extratropical teleconnections. We investigate such dynamics by prescribing localized thermal forcing at different ocean basins in an atmospheric model coupled to a slab ocean model that features realistic geography. When the forcing is located in the extratropics, the pattern of tropical climate response is nearly independent of the forcing location. In particular, any extratropical forcing that induces a northward shift of the Intertropical Convergence Zone is accompanied by a La Nina-like pattern of sea surface temperature response, resulting from climatological wind patterns and cloud distributions. In contrast, the tropical forcing in the Pacific and the Atlantic Ocean basins produces the tropical response patterns that are largely opposite. The northern tropical Pacific warming induces an overall tropical warming with a weakening of the Walker circulation, while the northern tropical Atlantic warming induces a basin-wide cooling in the Pacific with a strengthening of the Walker circulation. Investigation of remote climate response to localized forcing will provide a route to ask where focus should be applied in model development in order to reduce longstanding biases in climate models.