Korea Institute of Geoscience and Mineral Resources, Daejeon, 34132, Korea.
Korea University of Science and Technology (UST), Daejeon, 34113, Korea.
Sci Rep. 2020 Oct 20;10(1):17814. doi: 10.1038/s41598-020-74994-x.
East Asian summer monsoon (EASM)-driven rapid hydroclimatic variation is a crucial factor with major socioeconomic impacts. Nevertheless, decadal- to centennial-scale EASM variability over the last two millennia is still poorly understood. Pollen-based quantitative annual precipitation (PqPann) and annual precipitation reconstructed by artificial neural networks (ANNs) for the period 650-1940 CE were reconstructed from a paleo-reservoir in South Korea. ANNs reconstruction was performed to compensate for a hiatus section. On a decadal timescale, 10 high-precipitation periods were identified, and PqPann and ANNs reconstructions were comparable to local instrumental rainfall and historic drought records. Biotic lags to rapid climatic changes ranging from 25 to 100 years were recognized by asynchronous pollen and speleothem responses to precipitation. We suggest that PqPann-based decadal- to centennial-scale climatic change reconstruction should take biotic lags into account, although the lags can be ignored on the millennial scale. The position of the EASM rainband influenced rainfall magnitude.
东亚夏季风（EASM）驱动的快速水文气候变化是一个具有重大社会经济影响的关键因素。然而，在过去两千年中，EASM 在数十年至百年时间尺度上的变化仍然知之甚少。本研究利用韩国一个古水库中的花粉资料，重建了公元前 650 年至 1940 年期间的花粉定量年降水量（PqPann）和人工神经网络（ANNs）重建的年降水量。ANNs 重建是为了弥补一个 hiatus 部分。在十年时间尺度上，识别出了 10 个高降水期，PqPann 和 ANNs 重建结果与当地仪器降水和历史干旱记录相当。通过花粉和洞穴石笋对降水的异步响应，认识到生物滞后于快速气候变化的范围从 25 年到 100 年不等。我们认为，尽管在千年时间尺度上可以忽略滞后，但基于 PqPann 的数十年至百年时间尺度的气候变化重建应该考虑生物滞后。EASM 雨带的位置影响了降雨量的大小。
