Modern precipitation over northeastern (NE) South America is strongly controlled by the seasonal meridional migration of the Intertropical Convergence Zone (ITCZ). Ample evidence from the Northern Hemisphere suggests a mid‐ to late Holocene southward migration of the ITCZ. Such a shift would be expected to increase precipitation over semi‐arid northern NE Brazil (Southern Hemisphere). However, the most robust precipitation record from northern NE Brazil shows a drying trend throughout the Holocene. Here, we address this issue presenting a high‐temporal resolution reconstruction of precipitation over northern NE Brazil based on data from a marine sediment core, together with analyses of mid‐ and late Holocene simulations performed with the fully coupled climate model FGOALS‐s2. Both, our data and the climate model simulations show a decrease in precipitation over northern NE Brazil from the mid‐ to the late Holocene. The model outputs further indicate a latitudinal contraction of the seasonal migration range of the ITCZ that, together with an intensification of the regional Walker circulation, were responsible for the mid‐ to late Holocene changes in precipitation over NE South America. Our results reconcile apparently conflicting precipitation records and climate mechanisms used to explain changes in precipitation over NE South America.

中文翻译：

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南美洲东北部热带辐合带中新世中期至晚期收缩

南美洲东北部（NE）的现代降水受到热带辐合带（ITCZ）的季节性经向迁移的强烈控制。北半球的大量证据表明，ITCZ是全新世中期到晚期向南的迁移。预计这种转变将增加巴西北部东北部（南半球）半干旱地区的降水。但是，巴西东北部北部最强劲的降水记录表明，整个全新世都出现了干旱的趋势。在这里，我们针对这个问题提出了一个基于海洋沉积物核心数据的巴西北部东北部降水的高分辨率高分辨率重建方法，并使用完全耦合的气候模型FGOALS-s2对中全新世模拟进行了分析。两个都，我们的数据和气候模型模拟表明，从全新世中期到晚期，巴西东北部北部的降水减少。该模型的输出进一步表明，ITCZ季节性迁移范围的纬度收缩，加上区域Walker环流的加剧，是造成南美东北部中新世中晚期降水变化的原因。我们的结果调和了明显矛盾的降水记录和用来解释南美东北部地区降水变化的气候机制。是造成南美东北部中新世中期至后期降水变化的原因。我们的结果调和了明显矛盾的降水记录和用来解释南美东北部地区降水变化的气候机制。是造成南美东北部中新世中期至后期降水变化的原因。我们的结果调和了明显矛盾的降水记录和用来解释南美东北部地区降水变化的气候机制。