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
Dew and fog play major roles in providing the atmospheric moisture for plants and arthropods living in arid regions all over the world. Studies are needed to discriminate between dew and fog. A radiation system was de...Dew and fog play major roles in providing the atmospheric moisture for plants and arthropods living in arid regions all over the world. Studies are needed to discriminate between dew and fog. A radiation system was developed for measuring the incoming and outgoing solar （shortwave） radiation using two CM21 Kipp ＆ Zonen pyranometers （one inverted）, and the incoming （atmospheric） and outgoing （terrestrial） longwave radiation using two CG1 pyrgeometers in Logan （41047＇ N, 111~51＇ W, 1,460 m above mean sea level）, Utah, USA, continuously since 1995. These instruments are ventilated with heated air to prevent precipitation of dew and frost on the sensors, which otherwise would disturb the measurements. Based upon these measurements and an algorithm, the cloud base height, the cloud base temperature and percent of cloudiness can be parameterized at local scale. A cloud base height around zero would indicate fog at the local scale. In 1999, Bowen ratio system was added to measure the evapotranspiration, dew and frost continuously throughout the year at the same location close to the radiation system. Combining these two systems （radiation and Bowen ratio） has yielded a reasonable approach to differentiate between the atmospheric moistures collected by dew and fog.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。
文摘Dew and fog play major roles in providing the atmospheric moisture for plants and arthropods living in arid regions all over the world. Studies are needed to discriminate between dew and fog. A radiation system was developed for measuring the incoming and outgoing solar （shortwave） radiation using two CM21 Kipp ＆ Zonen pyranometers （one inverted）, and the incoming （atmospheric） and outgoing （terrestrial） longwave radiation using two CG1 pyrgeometers in Logan （41047＇ N, 111~51＇ W, 1,460 m above mean sea level）, Utah, USA, continuously since 1995. These instruments are ventilated with heated air to prevent precipitation of dew and frost on the sensors, which otherwise would disturb the measurements. Based upon these measurements and an algorithm, the cloud base height, the cloud base temperature and percent of cloudiness can be parameterized at local scale. A cloud base height around zero would indicate fog at the local scale. In 1999, Bowen ratio system was added to measure the evapotranspiration, dew and frost continuously throughout the year at the same location close to the radiation system. Combining these two systems （radiation and Bowen ratio） has yielded a reasonable approach to differentiate between the atmospheric moistures collected by dew and fog.
