通过黔北三星洞2支石笋(编号:SX3-a和SX14)的25个高精度230Th年龄(测年误差≤76 a)和740个氧同位素数据,重建了末次冰消期至早全新世(16.82±0.04~8.29±0.03 ka B.P.)平均分辨率达10 a的亚洲夏季风演变历史。无论在千年尺度还...通过黔北三星洞2支石笋(编号:SX3-a和SX14)的25个高精度230Th年龄(测年误差≤76 a)和740个氧同位素数据,重建了末次冰消期至早全新世(16.82±0.04~8.29±0.03 ka B.P.)平均分辨率达10 a的亚洲夏季风演变历史。无论在千年尺度还是百年尺度,甚至是十年际气候事件上,三星石笋δ18O记录的季风气候与北高纬气候都存在耦合关系。然而,在波令-阿勒罗德(B?lling-Aller?d)时期,与格陵兰冰芯所记录的温度逐渐回冷的趋势相反,亚洲夏季风表现出逐渐增强的过程。太阳辐射能量的增加和越赤道气流的增强有可能是引起此时期夏季风增强的主要原因。在前北方期(11.7~9 ka B.P.)时,南极温度、大气CO2浓度和CH4浓度等在新仙女木(Younger Dryas,YD)结束后均达到最大值,而石笋δ18O记录表明在YD冷事件结束后,直到9 ka B.P.左右亚洲夏季风才达到最盛期。冰消期结束后,虽然太阳辐射能量已经达到高值,但直到9 ka B.P.之前,北美大陆仍然残留较大的冰盖,有可能对夏季风的增强起到一定的限制作用。另外,早全新世南极变冷同样有可能通过加强越赤道气流来影响夏季风气候。展开更多
An interdecadal shift in summer (June―August) sea surface temperature (SST) variations during the period of 1968―2002 was identified in the late 1980s, which is characterized by a phase alternating from negative to ...An interdecadal shift in summer (June―August) sea surface temperature (SST) variations during the period of 1968―2002 was identified in the late 1980s, which is characterized by a phase alternating from negative to positive phases of the leading mode of the empirical orthogonal function (EOF) analysis of the summer monthly mean SST in the Pacific domain 100°―180°E and 0°―40°N, accounting for 30.5% of the total variance. During the period of 1968―1987, the leading mode with a mean negative phase state (mean standard deviation = ?0.586) controlled SST variability in the western North Pacific. Correspondingly, negative SST anomalies occupied the western North Pacific south of Japan and Chinese marginal seas. During the period of 1988―2002, the leading mode shifted to its strong positive polarity (mean standard deviation = 0.781), thus positive SST anomalies appeared in the western North Pacific. Accompanied by the interdecadal shift in summer mean SST, summer mean rainfall increased in southern and southeastern China during the late period, particularly in southeastern China where increase in summer mean rainfall exceeded 40 mm, at the 0.05 significance level.展开更多
文摘通过黔北三星洞2支石笋(编号:SX3-a和SX14)的25个高精度230Th年龄(测年误差≤76 a)和740个氧同位素数据,重建了末次冰消期至早全新世(16.82±0.04~8.29±0.03 ka B.P.)平均分辨率达10 a的亚洲夏季风演变历史。无论在千年尺度还是百年尺度,甚至是十年际气候事件上,三星石笋δ18O记录的季风气候与北高纬气候都存在耦合关系。然而,在波令-阿勒罗德(B?lling-Aller?d)时期,与格陵兰冰芯所记录的温度逐渐回冷的趋势相反,亚洲夏季风表现出逐渐增强的过程。太阳辐射能量的增加和越赤道气流的增强有可能是引起此时期夏季风增强的主要原因。在前北方期(11.7~9 ka B.P.)时,南极温度、大气CO2浓度和CH4浓度等在新仙女木(Younger Dryas,YD)结束后均达到最大值,而石笋δ18O记录表明在YD冷事件结束后,直到9 ka B.P.左右亚洲夏季风才达到最盛期。冰消期结束后,虽然太阳辐射能量已经达到高值,但直到9 ka B.P.之前,北美大陆仍然残留较大的冰盖,有可能对夏季风的增强起到一定的限制作用。另外,早全新世南极变冷同样有可能通过加强越赤道气流来影响夏季风气候。
基金Supported by the National Key Basic Research and Development Project of China (Grant Nos. 2004CB418302 and 2007CB411505)the National Natural Science Foundation of China (Grant Nos. 40475030 and 40225012)
文摘An interdecadal shift in summer (June―August) sea surface temperature (SST) variations during the period of 1968―2002 was identified in the late 1980s, which is characterized by a phase alternating from negative to positive phases of the leading mode of the empirical orthogonal function (EOF) analysis of the summer monthly mean SST in the Pacific domain 100°―180°E and 0°―40°N, accounting for 30.5% of the total variance. During the period of 1968―1987, the leading mode with a mean negative phase state (mean standard deviation = ?0.586) controlled SST variability in the western North Pacific. Correspondingly, negative SST anomalies occupied the western North Pacific south of Japan and Chinese marginal seas. During the period of 1988―2002, the leading mode shifted to its strong positive polarity (mean standard deviation = 0.781), thus positive SST anomalies appeared in the western North Pacific. Accompanied by the interdecadal shift in summer mean SST, summer mean rainfall increased in southern and southeastern China during the late period, particularly in southeastern China where increase in summer mean rainfall exceeded 40 mm, at the 0.05 significance level.
