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71.
粒度和磁化率记录的毛乌素沙地东缘全新世气候变化 总被引:3,自引:2,他引:1
通过对毛乌素沙地东缘大柳塔剖面地层沉积物粒度及磁化率特征的分析,结合光释光测年结果,探讨了毛乌素沙地全新世气候变化。结果表明:(1)剖面沉积物粒度组成以中砂、粗砂为主,古土壤中黏粒组分含量高(3.32%),风成砂中几乎不含黏粒组分(0.01%),粒度参数的平均粒径M_z和分选系数σ也表现为古土壤高值、风成砂低值;(2)磁化率在全剖面呈有规律的变化,低频、高频磁化率在古土壤中呈高值,湖沼相、弱成壤次之,风成砂最小;低频磁化率χlf与黏粒(<2μm)含量、平均粒径M_z呈显著正相关,垂向剖面上变化规律一致,指示了相似的气候环境意义;(3)毛乌素沙地在10.39 ka BP附近存在明显的3次冷干-暖湿气候波动; 10.39~9.34 ka BP,气候冷干,风沙活动盛行; 9.34~8.68 ka BP,冬季风衰退,夏季风增强,成壤作用强烈; 8.68~8.29 ka BP,气候寒冷干燥; 8.29~2.72 ka BP,气候整体温暖湿润,在6.55~3.80 ka BP达到鼎盛后转向冷干; 2.72~1.34 ka BP,冬季风占主导,沙丘活化,沙漠扩张; 1.34 ka BP至今,逐渐接近现代气候。毛乌素沙地的全新世气候变化是东亚冬、夏季风此消彼长作用下全球气候变化的区域响应。 相似文献
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WANG Shaoqiang WANG Junbang ZHANG Leiming XIAO Zhishu WANG Feng SUN Nan LI Daiqing CHEN Bin CHEN Jinghua LI Yue WANG Xiaobo WANG Miaomiao 《资源与生态学报(英文版)》2019,10(2):105-111
Ecological quality is defined as the stability, adaptability and resilience of an ecosystem. Monitoring and assessing ecological quality are important bases for China's ecological civilization construction. The national key research and development program “Technologies and guidelines for monitoring ecological quality of terrestrial ecosystems in China”, launched in July 2017, includes plans to study the observation technologies and provide guidelines on the ecological in-situ observation, the regional biodiversity and ecosystem function monitoring and its applications, all of which contribute to national ecological quality assessment. A year after its implementation, some important progress has been achieved, such as building the indicator system for comprehensive monitoring of ecological quality and improvement of the methods, mass data transmission, infrared camera-based monitoring of biodiversity, multi-angle automatic spectral observation systems, and unmanned aerial vehicle (UAV) based desert monitoring. We have organized this special issue and attempted to introduce the monitoring techniques and assessment methods on ecological quality from different perspectives in order to further promote the development of ecology and its observation methods. 相似文献
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Surface modeling with very large data sets is challenging. An efficient method for modeling massive data sets using the high accuracy surface modeling method (HASM) is proposed, and HASM_Big is developed to handle very large data sets. A large data set is defined here as a large spatial domain with high resolution leading to a linear equation with matrix dimensions of hundreds of thousands. An augmented system approach is employed to solve the equality-constrained least squares problem (LSE) produced in HASM_Big, and a block row action method is applied to solve the corresponding very large matrix equations. A matrix partitioning method is used to avoid information redundancy among each block and thereby accelerate the model. Experiments including numerical tests and real-world applications are used to compare the performances of HASM_Big with its previous version, HASM. Results show that the memory storage and computing speed of HASM_Big are better than those of HASM. It is found that the computational cost of HASM_Big is linearly scalable, even with massive data sets. In conclusion, HASM_Big provides a powerful tool for surface modeling, especially when there are millions or more computing grid cells. 相似文献
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Yue Tianxiang Zhao Na Liu Yu Wang Yifu Zhang Bin Du Zhengping Fan Zemeng Shi Wenjiao Chen Chuanfa Zhao Mingwei Song Dunjiang Wang Shihai Song Yinjun Yan Changqing Li Qiquan Sun Xiaofang Zhang Lili Tian Yongzhong Wang Wei Wang Ying’an Ma Shengnan Huang Hongsheng Lu Yimin Wang Qing Wang Chenliang Wang Yuzhu Lu Ming Zhou Wei Liu Yi Yin Xiaozhe Wang Zong Bao Zhengyi Zhao Miaomiao Zhao Yapeng Jiao Yimeng Naseer Ufra Fan Bin Li Saibo Yang Yang Wilson John P. 《中国科学:地球科学(英文版)》2020,63(8):1092-1112
We propose a fundamental theorem for eco-environmental surface modelling(FTEEM) in order to apply it into the fields of ecology and environmental science more easily after the fundamental theorem for Earth's surface system modeling(FTESM). The Beijing-Tianjin-Hebei(BTH) region is taken as a case area to conduct empirical studies of algorithms for spatial upscaling, spatial downscaling, spatial interpolation, data fusion and model-data assimilation, which are based on high accuracy surface modelling(HASM), corresponding with corollaries of FTEEM. The case studies demonstrate how eco-environmental surface modelling is substantially improved when both extrinsic and intrinsic information are used along with an appropriate method of HASM. Compared with classic algorithms, the HASM-based algorithm for spatial upscaling reduced the root-meansquare error of the BTH elevation surface by 9 m. The HASM-based algorithm for spatial downscaling reduced the relative error of future scenarios of annual mean temperature by 16%. The HASM-based algorithm for spatial interpolation reduced the relative error of change trend of annual mean precipitation by 0.2%. The HASM-based algorithm for data fusion reduced the relative error of change trend of annual mean temperature by 70%. The HASM-based algorithm for model-data assimilation reduced the relative error of carbon stocks by 40%. We propose five theoretical challenges and three application problems of HASM that need to be addressed to improve FTEEM. 相似文献
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1700—1978年云南山地掌鸠河流域耕地时空演变的网格化重建 总被引:2,自引:0,他引:2
基于多源数据资料重建小尺度区域历史时期土地利用/覆盖变化,对深入理解土地利用变化的驱动力机制及其环境和气候效应具有重要意义。本文利用从流域尺度聚落格局演变重建到聚落尺度耕地数量和空间分布重建,再到流域尺度耕地格局重建的思路,以云南山地典型的中小流域为研究区,以历史文献资料、田野考察资料、历史地理学研究成果、档案资料、现代统计资料、地理基础数据为支撑,综合考虑区域自然因素(坡度、海拔高度)、人文因素(人口、政策、农业技术、耕地与居民点距离),设计了历史时期山地小尺度区域耕地网格化重建模型,重建了1700—1978年具有明确时间和空间属性的网格化耕地格局。结果表明:① 掌鸠河流域的耕地面积近300 a增长6.3倍,垦殖率从1700年的2.1%上升到1978年的15.6%。② 不同地形区的耕地面积差异较为显著,其中山区和半山区的耕地面积最大,且增长速度最快;平坝区和中下游河谷区的耕地面积增长相对平缓,是自然环境、人口、政策和农业技术等因素综合作用的结果。③ 通过总耕地面积和人均耕地面积等对结果进行验证,证明了重建结果的合理性。本文设计的网格化重建模型可以为模拟具有明确时间和空间属性的小尺度区域历史耕地网格化数据集提供参考。 相似文献
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双翻斗雨量传感器标校过程中,对于不同雨强超差方向相反的雨量计需要分别调节上翻斗的定位螺钉和计量翻斗的容量调节螺钉,同时也需要记录上翻斗和计量翻斗的翻动次数。雨量计使用的是无源脉冲输出,计量翻斗的每次翻动触发干簧管产生一个脉冲,利用单片机即可采集这个信号自动记录。而上翻斗的翻动次数靠人工观察统计,由于翻斗翻动速度较快人工计数不准确,最终造成标校不准。并且人工每次只能记录1台雨量计,无法批量自动记录数据。本文采用光纤传感器在不干扰雨量计运行情况下自动统计上翻斗翻动次数,为标校提供准确数据。 相似文献