气候模式中陆地-海洋增温对比的辐射与动力控制机制

中文摘要 AI 辅助

在温室气体强迫下，陆地表面空气的增温幅度显著大于海洋，这一现象被称为陆地-海洋增温对比。当前对该对比的解释通常分为两类：一类是基于能量约束，来自大气层顶和表面能量平衡；另一类是基于动力约束，来自大尺度大气动力学。本文表明，通过大气湿静力能（MSE）输送的视角来看，这两类视角是互补的，将它们结合能为增温对比的控制机制及气候模式间的差异提供新的见解。我们利用该框架构建了一个可解释的模拟器，其能再现最新的耦合模式比较计划（CMIP6）中22个模式的陆地-海洋增温响应。我们发现，陆地-海洋增温对比的强度源于模式依赖的辐射基线与有利于陆地增温的稳健动力恢复机制之间的相互作用，这种相互作用形成了与气候敏感度一致的两大模式 regime（ regime 译为“类别”）。在低气候敏感度模式中，海洋上更具稳定性的辐射反馈直接有利于陆地增温；在高气候敏感度模式中，仅辐射反馈本应有利于海洋增温，但强度约为0.2 PW/K 的强 MSE 输送反馈可充分抵消这一趋势。陆地-海洋增温对比的模式间差异与陆地和海洋辐射反馈的比值密切相关，凸显了气候敏感度与陆地-海洋增温对比之间的更广泛联系。

英文摘要

Surface air over land warms substantially more than over the ocean under greenhouse forcing, a phenomenon known as the land-ocean warming contrast. Current explanations for this contrast are commonly expressed either in terms of energetic constraints, from top-of-atmosphere and surface energy balance, or dynamical constraints, from large-scale atmospheric dynamics. We show that these perspectives are complementary when viewed through the lens of atmospheric moist static energy (MSE) transport, and that connecting them yields new insight into the controls of the warming contrast and the spread in climate models. We use this framework to construct an interpretable emulator that reproduces the land-ocean warming response across 22 models from the latest Coupled Model Intercomparison Project (CMIP6). We find that the strength of the land-ocean warming contrast emerges from the interplay between a model-dependent radiative baseline and a robust dynamical restoring mechanism that favors greater warming over land. This interplay leads to two broad model regimes that align with climate sensitivity. In low-climate-sensitivity models, more stabilizing radiative feedbacks over the ocean directly favor greater land warming. In high-climate-sensitivity models, radiative feedbacks alone would instead favor greater ocean warming, but a strong MSE-transport feedback (approximately 0.2 PW/K) more than compensates for this tendency. The intermodel spread in the land-ocean warming contrast is closely related to the ratio of radiative feedbacks over land and ocean, highlighting a broader connection between climate sensitivity and the land-ocean warming contrast.

发表机构

• Massachusetts Institute of Technology（麻省理工学院）

机构由 AI 辅助整理，请以论文原文为准。