Purpose of Review

The intertropical convergence zone (ITCZ) is a planetary-scale band of heavy precipitation close to the equator. Here, we consider the response of the ITCZ structure to climate change using observations, simulations, and theory. We focus on the substantial yet underappreciated projected changes in ITCZ width and strength, and highlight an emerging conceptual framework for understanding these changes.

Recent Findings

Satellite observations and reanalysis data show a narrowing and strengthening of precipitation in the ITCZ over recent decades in both the Atlantic and Pacific basins, but little change in ITCZ location. Consistent with observations, coupled climate models predict no robust change in the zonal-mean ITCZ location over the twenty-first century. However, the majority of models project a narrowing of the ITCZ and weakening mean ascent. Interestingly, changes in ITCZ width and strength are strongly anti-correlated across models.

Summary

The ITCZ has narrowed over recent decades yet its location has remained approximately constant. Climate models project further narrowing and a weakening of the average ascent within the ITCZ as the climate continues to warm. Following intense work over the last ten years, the physical mechanisms controlling the ITCZ location are now well understood. The development of complementary theories for ITCZ width and strength is a current research priority. Outstanding challenges include understanding the ITCZ response to past climate changes and over land versus ocean regions, and better constraining all aspects of the ITCZ structure in model projections.

中文翻译：

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热带辐合带对气候变化的响应：位置、宽度和强度。

审查目的

热带辐合带（ITCZ）是靠近赤道的一个行星级强降水带。在这里，我们使用观测、模拟和理论来考虑 ITCZ 结构对气候变化的响应。我们专注于 ITCZ 宽度和强度的重大但未被充分认识的预计变化，并强调理解这些变化的新兴概念框架。

最近的发现

卫星观测和再分析数据显示，近几十年来，大西洋和太平洋盆地的 ITCZ 降水量都在缩小和加强，但 ITCZ 位置几乎没有变化。与观测结果一致，耦合气候模型预测 21 世纪纬向平均 ITCZ 位置不会发生剧烈变化。然而，大多数模型预测 ITCZ 变窄和平均上升减弱。有趣的是，ITCZ 宽度和强度的变化在模型之间具有很强的反相关性。

概括

近几十年来，ITCZ 已经缩小，但其位置基本保持不变。随着气候继续变暖，气候模型预测 ITCZ 内的平均上升幅度会进一步缩小和减弱。经过过去十年的紧张工作，现在人们对控制 ITCZ 位置的物理机制有了很好的了解。发展 ITCZ 宽度和强度的互补理论是当前的研究重点。突出的挑战包括了解 ITCZ 对过去气候变化和陆地与海洋区域的响应，以及在模型预测中更好地约束 ITCZ 结构的各个方面。