Studies on a high resolution loess section in Huining County reveal that the behavior of climate shows high instability during the last glaciation. Results reflect that climate in Loess Plateau oscillates on millennia...Studies on a high resolution loess section in Huining County reveal that the behavior of climate shows high instability during the last glaciation. Results reflect that climate in Loess Plateau oscillates on millennial time scales during the last glacial period. These can be teleconnected with the records of Dansgaard-Oeschger cycles and Heinrich events in high latitudes. Results also demonstrate that variations in the intensity of wind regime on the Loess Plateau have a close correlation with the changes of global ice sheets volume. All these suggest that two-level fordngs may drive climate changes in central Asia. The first level is the volume changes of ice sheets and the second level with short time scales is superimposed upon the first level on a nearly global scale.展开更多
Eighty-one samples were selected from the Late Pleistocene Xifeng loess profile and analyzed for their element abundances using instrumental neutron activation analysis, and for 10Be using the AMS method. The results ...Eighty-one samples were selected from the Late Pleistocene Xifeng loess profile and analyzed for their element abundances using instrumental neutron activation analysis, and for 10Be using the AMS method. The results show that the variations of element abundance and 10Be with depth are similar to those of δ18O in DSDP, and may be considered as an indicator of climatic and environmental changes.展开更多
为了分析黄土高原地区植被物候特征,该文基于AVHRR传感器获取的陆地长期数据记录(land long term data record,LTDR)V4 NDVI数据,对黄土高原1982-2011年间植被物候的时空变化进行分析,并借助偏相关分析方法对物候与气温和降雨的关系进...为了分析黄土高原地区植被物候特征,该文基于AVHRR传感器获取的陆地长期数据记录(land long term data record,LTDR)V4 NDVI数据,对黄土高原1982-2011年间植被物候的时空变化进行分析,并借助偏相关分析方法对物候与气温和降雨的关系进行量化分析。结果表明:黄土高原近30 a间春季物候提前显著(0.54 d/a,P<0.001),主要集中在北部草地和灌木植被;秋季物候推迟显著(0.74 d/a,P<0.001),主要分布在甘肃、陕北、内蒙古和山西北部等地。不同植被的春秋物候稍有差异,稀疏灌木林春季物候提前趋势最多(1.31 d/a),常绿针叶林最小(0.19 d/a);秋季物候推迟最多的为乔木园地(1.18 d/a),最少的是水田(0.17 d/a)。黄土高原植被物候主要受气温影响,降雨的变化也会对物候产生一定影响。冬季和前年秋季气温上升是春季物候提前的主要驱动因子;夏季和秋季降雨则对秋季物候休眠期延迟起着重要作用。该研究可为黄土高原生态环境评价及气候变化预测模型提供一定依据。展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘Studies on a high resolution loess section in Huining County reveal that the behavior of climate shows high instability during the last glaciation. Results reflect that climate in Loess Plateau oscillates on millennial time scales during the last glacial period. These can be teleconnected with the records of Dansgaard-Oeschger cycles and Heinrich events in high latitudes. Results also demonstrate that variations in the intensity of wind regime on the Loess Plateau have a close correlation with the changes of global ice sheets volume. All these suggest that two-level fordngs may drive climate changes in central Asia. The first level is the volume changes of ice sheets and the second level with short time scales is superimposed upon the first level on a nearly global scale.
文摘Eighty-one samples were selected from the Late Pleistocene Xifeng loess profile and analyzed for their element abundances using instrumental neutron activation analysis, and for 10Be using the AMS method. The results show that the variations of element abundance and 10Be with depth are similar to those of δ18O in DSDP, and may be considered as an indicator of climatic and environmental changes.
文摘为了分析黄土高原地区植被物候特征,该文基于AVHRR传感器获取的陆地长期数据记录(land long term data record,LTDR)V4 NDVI数据,对黄土高原1982-2011年间植被物候的时空变化进行分析,并借助偏相关分析方法对物候与气温和降雨的关系进行量化分析。结果表明:黄土高原近30 a间春季物候提前显著(0.54 d/a,P<0.001),主要集中在北部草地和灌木植被;秋季物候推迟显著(0.74 d/a,P<0.001),主要分布在甘肃、陕北、内蒙古和山西北部等地。不同植被的春秋物候稍有差异,稀疏灌木林春季物候提前趋势最多(1.31 d/a),常绿针叶林最小(0.19 d/a);秋季物候推迟最多的为乔木园地(1.18 d/a),最少的是水田(0.17 d/a)。黄土高原植被物候主要受气温影响,降雨的变化也会对物候产生一定影响。冬季和前年秋季气温上升是春季物候提前的主要驱动因子;夏季和秋季降雨则对秋季物候休眠期延迟起着重要作用。该研究可为黄土高原生态环境评价及气候变化预测模型提供一定依据。
