2023年3月1日出版的《自然》杂志发表了一项最新研究成果，来自英国牛津大学的 Munday, Callum小组揭示了山谷的形成使东非干旱，并增加刚果盆地的降雨量。

数值模型实验表明，贯穿6000公里长的东非大裂谷系统(EARS)上的山谷是东非干旱条件发展的核心。这些山谷，包括肯尼亚的图尔卡纳盆地，通过将水汽引向中非，使东非变得干燥，这一过程同时增加了刚果盆地雨林的降雨量。没有了山谷，裂谷系统的隆起导致东非的气候更加湿润，而刚果盆地的气候更加干燥。气候模式实验结果表明，非洲详细的构造发展塑造了降雨分布，对非洲植物和动物谱系的进化具有深远的影响。

据介绍，在过去的800万年中，东非干旱化经常被认为是植被大规模变化和包括古人类在内的新动物谱系进化的驱动因素。然而，干旱加剧的证据存在争议，而且最关键的是，导致干旱的机制尚不清楚。

附：英文原文

Title: Valley formation aridifies East Africa and elevates Congo Basin rainfall

Author: Munday, Callum, Savage, Nicholas, Jones, Richard G., Washington, Richard

Issue&Volume: 2023-03-01

Abstract: East African aridification during the past 8 million years is frequently invoked as a driver of large-scale shifts in vegetation and the evolution of new animal lineages, including hominins. However, evidence for increasing aridity is debated and, crucially, the mechanisms leading to dry conditions are unclear. Here, numerical model experiments show that valleys punctuating the 6,000-km-long East African Rift System (EARS) are central to the development of dry conditions in East Africa. These valleys, including the Turkana Basin in Kenya, cause East Africa to dry by channelling water vapour towards Central Africa, a process that simultaneously enhances rainfall in the Congo Basin rainforest. Without the valleys, the uplift of the rift system leads to a wetter climate in East Africa and a drier climate in the Congo Basin. Results from climate model experiments demonstrate that the detailed tectonic development of Africa has shaped the rainfall distribution, with profound implications for the evolution of African plant and animal lineages.

DOI: 10.1038/s41586-022-05662-5

Source: https://www.nature.com/articles/s41586-022-05662-5