|综述了亚洲中部干旱区湖泊研究的古气候记录,发现湖泊记录的全新世有效湿度在大框架上具有一致性变化.据此,选择了其中年代可靠、代用指标湿度意义明确、时间分辨率较高的8个地点的记录,半定量地集成了中东亚干旱区全新世期间湿度的变化.结果表明,亚洲内陆干旱区全新世气候变化具有较清晰的阶段性变化,大约8cal kaBP以前的早全新世气候干旱,8-4cal kaBP的中全新世气候湿润,从距今5-6cal kaBP以来湿润程度逐步降低到晚全新世,但晚全新世比早全新世湿润.内陆干旱区的全新世湿度变化框架与最新获得的亚洲季风变化模式存在较大差异,因此推论出,北大西洋海洋表面的温度变化可能是中东亚干旱区湿度的主要影响因素.
|关键词: 中东亚干旱区 全新世 湖泊 湿度
|The pattern of Holocene climate change in the arid central Asia: a case study based on lakes
AN Chengbang, CHEN Fahu
Key Laboratory of Western China's Environmental Systems (Ministry of Education), Lanzhou University, Lanzhou 730000, P. R. China
|The palaeoclimate records from lakes at the arid central Asian region (ACA) climatically dominated by the Westerly circulation shows synchronous and coherent moisture changes during the Holocene. Therefore, the sediment records from lakes in ACA with reliable chronologies and robust proxies were selected to reconstruct moisture histories based on a five-class ordinal wetness index with assigned scores from the driest to wettest periods at individual sites for 200-year time slices. There are 8 lakes suitable for the synthesis. The results show that ACA as a whole experienced a dry early Holocene, a wetter (less dry) early to mid-Holocene, and a moderately wet late Holocene, which is different from Holocene monsoon history recently recovered by documents such as speleothem. We propose that the pattern of Holocene effective-moisture evolution in the westerly dominated ACA was mainly determined by North Atlantic sea-surface temperatures (SSTs) and high-latitude air temperatures that affect the availability, amount and transport of water vapor.
|Key words: Mid-latitude arid central Asia Holocene lakes oisture changes