越南红河三角洲近五千年来的几个降温事件

根据对越南红河三角洲的2个钻孔的孢粉分析结果，结合沉积特征和高精度的AMS^14C测年数据，恢复了近五千年来百年一千年尺度的气候变化，发现了3个分别开始于4530cal．aBP，2100cal．aBP和620cal．aBP的明显降温事件，其中4530cal．aBP和620cal．aBP降温事件可与全球全新世气候变冷事件中的“新冰期(Neoglacial)”和“小冰期(Little Ice Age)”相对应，可能与由北大西洋地区几个短期变冷事件的全球气候响应机制有关。3340cal．aBP以来，人类干扰性植物成分的增加，表明人类活动对自然植被的影响改造作用增强，因此，本研究中气候的降温事件不排除人类影响的因素，仍需要进一步深入研究。

Several Cooling Events Over the Hong River Delta,Vietnam During the Past 5,000 Years

Based on the palynological analysis results for two cores from the Hong River delta, Vietnam together with the sedimentary characteristics and the high precision AMS ~(14)C dating data, the centennial-to millennial-scale climate changes over this area during the past 5,000 years were reconstructed. Three obvious cooling events were revealed and began in 4,530 cal. a BP, 2,100 cal. a BP and 620 cal. a BP, respectively, among them, the cooling events beginning in 4,530 cal. a BP and 620 cal. a BP correspond to the global cooling events of Neoglacial and Little Ice Age, respectively, which might be related to the global climate response mechanism of the short-term cooling events in the North Atlantic Ocean area. Since 3,340 cal. a BP, the increase in vegetation components disturbed by human being has demonstrated the intensified influence of human activities on the natural vegetation, so the influence of human activities on the cooling events remains to be further studied.