基于黔西南雾露洞高分辨率石笋同位素记录,重建了62.0～58.2 ka BP和20.9～15.5 ka BP期间亚洲夏季风水文历史和洞穴岩溶环境变化过程。两支石笋(Wu58和Wu60)实测16个^(230)Th年龄和966组氧、碳同位素数据。结果显示,深海氧同位素3阶段(...基于黔西南雾露洞高分辨率石笋同位素记录,重建了62.0～58.2 ka BP和20.9～15.5 ka BP期间亚洲夏季风水文历史和洞穴岩溶环境变化过程。两支石笋(Wu58和Wu60)实测16个^(230)Th年龄和966组氧、碳同位素数据。结果显示,深海氧同位素3阶段(MIS 3)早期和2阶段(MIS 2)期间,千年尺度δ^(18)O变化非常显著,而δ^(13)C则在稳定的背景值下,呈百年尺度波动。去趋势发现,δ^(18)O指示的百年尺度弱季风事件与δ^(13)C指示的土壤CO_2产率衰减过程变化一致。两组同位素变化呈相似的百年尺度波动,共同周期约300 a,说明本区域土壤CO_2产率变化与百年尺度亚洲夏季风变化密切相关。在变化幅度上,δ^(13)C的振幅远大于δ^(18)O(约1.5～3.5倍),表明碳同位素变化对于气候响应具有放大效应,或者δ^(13)C与δ^(18)O变化具有不同的地球化学行为。通过与大气^(14)C、冰芯^(10)Be记录对比,发现百年尺度季风强弱及岩溶过程变化与太阳活动指标具有相似性,说明太阳活动对百年尺度季风强弱和土壤CO_2产率起到主控作用。可能的途径是,太阳活动通过海-陆热力差,影响夏季风强度和当地土壤湿度水平,并经生态效应进一步放大。然而,在百年尺度上,δ^(18)O振幅仅为0.4‰,远小于千年尺度变化(1.5‰)。因此,千年尺度亚洲夏季风突变的诱发因子可能不直接受控于太阳活动,需要其他驱动因素或者气候系统内部放大机制来解释。展开更多
Climate data from the Climatic Research Unit （CRU） for the period 1901-2013 are used to investigate the drought response to air temperature change over China on the centennial scale. Drought is observed to have incr...Climate data from the Climatic Research Unit （CRU） for the period 1901-2013 are used to investigate the drought response to air temperature change over China on the centennial scale. Drought is observed to have increased evidently across China, except for some regions in eastern China. This increase is much stronger in northern China compared to southern China, especially in Northwest and North China. These change characteris- tics of drought are closely associated with air temperature change, with the severe droughts in the major drought episodes of the last century generally coinciding with higher temperatures. The significantly increasing trend of drought in China based on observations only appears when considering the effects of air temperature change, which can explain -49% of droughts in observations and 30%-65% of droughts in Coupled Model Intereomparison Project Phase 5 （CMIP5） model simulations. Furthermore, the response of drought to air temperature change generally increases as the drought time scale increases. Furthermore, drought shows relatively high sensitivity in spring and early summer in China on the centennial scale.展开更多
文摘基于黔西南雾露洞高分辨率石笋同位素记录,重建了62.0～58.2 ka BP和20.9～15.5 ka BP期间亚洲夏季风水文历史和洞穴岩溶环境变化过程。两支石笋(Wu58和Wu60)实测16个^(230)Th年龄和966组氧、碳同位素数据。结果显示,深海氧同位素3阶段(MIS 3)早期和2阶段(MIS 2)期间,千年尺度δ^(18)O变化非常显著,而δ^(13)C则在稳定的背景值下,呈百年尺度波动。去趋势发现,δ^(18)O指示的百年尺度弱季风事件与δ^(13)C指示的土壤CO_2产率衰减过程变化一致。两组同位素变化呈相似的百年尺度波动,共同周期约300 a,说明本区域土壤CO_2产率变化与百年尺度亚洲夏季风变化密切相关。在变化幅度上,δ^(13)C的振幅远大于δ^(18)O(约1.5～3.5倍),表明碳同位素变化对于气候响应具有放大效应,或者δ^(13)C与δ^(18)O变化具有不同的地球化学行为。通过与大气^(14)C、冰芯^(10)Be记录对比,发现百年尺度季风强弱及岩溶过程变化与太阳活动指标具有相似性,说明太阳活动对百年尺度季风强弱和土壤CO_2产率起到主控作用。可能的途径是,太阳活动通过海-陆热力差,影响夏季风强度和当地土壤湿度水平,并经生态效应进一步放大。然而,在百年尺度上,δ^(18)O振幅仅为0.4‰,远小于千年尺度变化(1.5‰)。因此,千年尺度亚洲夏季风突变的诱发因子可能不直接受控于太阳活动,需要其他驱动因素或者气候系统内部放大机制来解释。
基金supported by the ‘Strategic Priority Research Program-Climate Change: Carbon Budget and Relevant Issues’ of the Chinese Academy of Sciences (Grant No.XDA05090306)the National Natural Science Foundation of China (Grant No. 41305061)the National Basic Research Program of China (Grant No. 2012CB955401)
文摘Climate data from the Climatic Research Unit （CRU） for the period 1901-2013 are used to investigate the drought response to air temperature change over China on the centennial scale. Drought is observed to have increased evidently across China, except for some regions in eastern China. This increase is much stronger in northern China compared to southern China, especially in Northwest and North China. These change characteris- tics of drought are closely associated with air temperature change, with the severe droughts in the major drought episodes of the last century generally coinciding with higher temperatures. The significantly increasing trend of drought in China based on observations only appears when considering the effects of air temperature change, which can explain -49% of droughts in observations and 30%-65% of droughts in Coupled Model Intereomparison Project Phase 5 （CMIP5） model simulations. Furthermore, the response of drought to air temperature change generally increases as the drought time scale increases. Furthermore, drought shows relatively high sensitivity in spring and early summer in China on the centennial scale.
