Abstract. Previous studies based on multiple paleoclimate archives suggested a prominent intensification of the South Asian Monsoon (SAM) during the mid-Holocene (MH, ~ 6000 years before present day). The main forcing that contributed to this intensification is related to changes in the Earth’s orbital parameters. However, other key factors likely played important roles, including remote changes in vegetation cover and airborne dust emission. In particular, northern Africa also experienced much wetter conditions and a more mesic landscape than today during the MH (the so-called African Humid Period), leading to a large decrease in airborne dust globally. However, most modelling studies investigating the SAM changes during the Holocene overlooked the potential impacts of the vegetation and dust emission changes that took place over northern Africa. Here, we use a set of simulations for the MH climate, in which vegetation over the Sahara and reduced dust concentrations are considered. Our results show that SAM rainfall is strongly affected by Saharan vegetation and dust concentrations, with a large increase in particular over northwestern India and a lengthening of the monsoon season. We propose that this remote influence is mediated by anomalies in Indian Ocean sea-surface temperatures and may have shaped the evolution of the SAM during the termination of the African Humid Period.

中文翻译：

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南亚季风对全新世中期减少粉尘排放和撒哈拉沙漠绿化的远程响应

摘要。先前基于多个古气候档案的研究表明，在全新世中期（MH，距今约6000年），南亚季风（SAM）明显增强。导致这种加剧的主要强迫与地球轨道参数的变化有关。但是，其他关键因素也可能起重要作用，包括植被覆盖率的远程变化和空气中的尘埃排放。特别是在MH（所谓的非洲湿润时期）期间，北部非洲也经历了比今天更湿润的环境和更陡峭的地形，导致全球空气中尘埃的大量减少。但是，大多数调查全新世期间SAM变化的建模研究都忽略了北非上空植被和尘埃排放变化的潜在影响。这里，我们针对MH气候使用了一组模拟，其中考虑了撒哈拉沙漠上的植被和尘埃浓度降低。我们的结果表明，SAM的降雨受撒哈拉植被和沙尘浓度的强烈影响，尤其是在印度西北部的大幅增加和季风季节的延长。我们认为，这种遥远的影响是由印度洋海表温度的异常调节的，并且可能在非洲湿润时期终止期间影响了SAM的演化。尤其是在印度西北部，并且季风季节延长了。我们认为，这种遥远的影响是由印度洋海表温度的异常调节的，并且可能在非洲湿润时期终止期间影响了SAM的演化。尤其是在印度西北部，并且季风季节延长了。我们认为，这种遥远的影响是由印度洋海表温度的异常调节的，并且可能在非洲湿润时期终止期间影响了SAM的演化。