We compared the stable carbon isotopic records from a loess transect of the Jiaochang in the eastern Tibetan Plateau, spanning the last -21,000 years, with multiproxy data for pedogenesis, including magnetic susceptib...We compared the stable carbon isotopic records from a loess transect of the Jiaochang in the eastern Tibetan Plateau, spanning the last -21,000 years, with multiproxy data for pedogenesis, including magnetic susceptibility, clay fraction, Fed/Fet ratio, carbonate and total organic carbon content, in order to probe the mechanisms of δ^13C values of organic matter and Late Quaternary climate variations in the eastern Tibetan Plateau. Our results indicate that there is no simple relationship between δ^13C of organic matter and summer monsoon variations. The change in δ^13C values of organic matter (in accordance with the ratios of C3 to C4 plants) results from the interaction among temperature, aridity and atmospheric pCO2 level. Drier climate and lower atmospheric pCO2 level contribute to positive carbon isotopic excursion, while negative carbon isotopic excursion is the result of lower temperature and increased atmospheric pCO2 level. Additionally, our results imply that the Tibetan monsoon may play an important role in climate system in the eastern Tibet Plateau, which specifically reflects frequently changing climate in that area. The results provide new insights into the forcing mechanisms on both the δ^13C values of organic matter and the local climate system.展开更多
实施乡村振兴战略,是党的十九大以来作出的重大决策部署。乡村振兴,关键是产业振兴。乡村国土地域系统及其产业组成要素之间的协调性决定了乡村持续振兴的能力。我国陇东地区乡村在长期的农业生产及城镇化发展中产业—空间矛盾尤为显著...实施乡村振兴战略,是党的十九大以来作出的重大决策部署。乡村振兴,关键是产业振兴。乡村国土地域系统及其产业组成要素之间的协调性决定了乡村持续振兴的能力。我国陇东地区乡村在长期的农业生产及城镇化发展中产业—空间矛盾尤为显著,迫切需要国土空间规划背景下的乡村产业—空间量化分类的探索性研究,客观反映乡村的发展程度,科学把握乡村发展差异和特点。本文充分剖析了国家与地区相关政策,进而通过分析该地区的产业-空间问题,基于“人地关系”协调理论构建“产村互动”耦合发展模型,以具备典型特征的陇东黄土高原沟壑区显胜乡村庄为研究对象,从产业与空间两大系统确定了19个评价因子,通过对评价因子进行赋值计算、运用地理信息系统(Geographic Information System,GIS)软件等手段,评价探析其产业—空间耦合互动的时空演变规律及内在机制,在规划响应方面得出如下启示:以科学评价现状为基础,分类引导乡村产业空间振兴;以统筹空间布局为核心,打造镇村一体发展新单元;以加强生态修复为策略,同步经济效益与空间效应;以延续历史文脉为补充,实现文化引领三产深度融合。展开更多
文摘We compared the stable carbon isotopic records from a loess transect of the Jiaochang in the eastern Tibetan Plateau, spanning the last -21,000 years, with multiproxy data for pedogenesis, including magnetic susceptibility, clay fraction, Fed/Fet ratio, carbonate and total organic carbon content, in order to probe the mechanisms of δ^13C values of organic matter and Late Quaternary climate variations in the eastern Tibetan Plateau. Our results indicate that there is no simple relationship between δ^13C of organic matter and summer monsoon variations. The change in δ^13C values of organic matter (in accordance with the ratios of C3 to C4 plants) results from the interaction among temperature, aridity and atmospheric pCO2 level. Drier climate and lower atmospheric pCO2 level contribute to positive carbon isotopic excursion, while negative carbon isotopic excursion is the result of lower temperature and increased atmospheric pCO2 level. Additionally, our results imply that the Tibetan monsoon may play an important role in climate system in the eastern Tibet Plateau, which specifically reflects frequently changing climate in that area. The results provide new insights into the forcing mechanisms on both the δ^13C values of organic matter and the local climate system.
文摘实施乡村振兴战略,是党的十九大以来作出的重大决策部署。乡村振兴,关键是产业振兴。乡村国土地域系统及其产业组成要素之间的协调性决定了乡村持续振兴的能力。我国陇东地区乡村在长期的农业生产及城镇化发展中产业—空间矛盾尤为显著,迫切需要国土空间规划背景下的乡村产业—空间量化分类的探索性研究,客观反映乡村的发展程度,科学把握乡村发展差异和特点。本文充分剖析了国家与地区相关政策,进而通过分析该地区的产业-空间问题,基于“人地关系”协调理论构建“产村互动”耦合发展模型,以具备典型特征的陇东黄土高原沟壑区显胜乡村庄为研究对象,从产业与空间两大系统确定了19个评价因子,通过对评价因子进行赋值计算、运用地理信息系统(Geographic Information System,GIS)软件等手段,评价探析其产业—空间耦合互动的时空演变规律及内在机制,在规划响应方面得出如下启示:以科学评价现状为基础,分类引导乡村产业空间振兴;以统筹空间布局为核心,打造镇村一体发展新单元;以加强生态修复为策略,同步经济效益与空间效应;以延续历史文脉为补充,实现文化引领三产深度融合。