冈底斯印支期造山事件:花岗岩类锆石U-Pb年代学和岩石成因证据

对冈底斯中部地区二云母花岗岩和花岗闪长岩进行了LA-ICP-MS锆石U-Pb定年、主量元素、微量元素和锆石Hf同位素组成的测定.结果表明, 二云母花岗岩的岩浆结晶年龄为(205± 1)Ma, 岩石属于强过铝质花岗岩, A/CNK= 1.16~ 1.20, K₂O/Na₂O= 1.67~ 1.95.岩石富Rb、Th和U等元素, Eu/Eu* = 0.29~ 0.41, (La/Yb)_N= 22.62~ 35.08.锆石ε_Hf(t)= -12.4~ -1.8.二云母花岗岩的岩浆产生于地壳中泥质岩类在无外来流体加入的情况下云母类矿物脱水反应所诱发的部分熔融作用, 其岩石形成机制类似于喜马拉雅新生代淡色花岗岩.花岗闪长岩的岩浆结晶年龄为(202± 1)Ma, 岩石属于准铝质(A/CNK= 0.96~ 0.98), K₂O/Na₂O= 1.42~ 1.77, Eu/Eu* = 0.54~ 0.65, (La/Yb)_N= 6.76~ 13.35.锆石ε_Hf(t)= -8.2~ -5.5.根据花岗闪长岩的地球化学特征和锆石Hf同位素组成, 花岗闪长岩的岩浆来自于地壳中基性岩类的部分熔融.冈底斯印支晚期强过铝质花岗岩的确定, 表明了冈底斯在印支晚期以前曾发生地壳的缩短与加厚作用, 从而进一步明确了冈底斯印支早期的造山事件及冈底斯经历了多期造山作用的演化.      

The Rangeland Livestock Carrying Capacity and Stocking Rate in the Kailash Sacred Landscape in China

Maintaining the health and productivity of rangelands by controlling the livestock stocking rate to remain within carrying capacity is of significance to ensure sustainable management of rangeland ecosystems. But we know little about the safe carrying capacity in particular rangeland landscapes. This has hampered efforts to use rangelands in a risk-averse manner in fluctuating rainfall environments, and especially in arid and semiarid areas. To address this lack of information, we took Kailash Sacred Landscape in China (KSL-China) as our study site and used remote sensing data, meteorological data and statistical data from 2000 to 2015 to analyze rangeland carrying capacity, stocking rate, and major influencing factors. Rangeland carrying capacity presented an increasing trend, while stocking rate was gradually decreasing, resulting in an increase of carrying rate in the study area. The increased carrying capacity was closely related to increased rainfall. Stocking rate declined owing to government regulations, particularly implementation in 2004 of the national policy of Returning Grazing Land to Grassland. There was a sharp reduction of livestock number below 200 000 standard sheep units (SU) after 2005. The decrease of stocking rate had a stronger effect on rangeland carrying rate than did the increase of carrying capacity. Ecosystem restoration programs have provided subsidies to pastoralists to encourage them to reduce livestock numbers. Our findings suggest that a safe rangeland carrying capacity is ca. 170 000 SU in KSL-China. There is a carrying capacity surplus of ca. 50 000 SU for safe animal husbandry development in the study area. More importantly, future climate warming and increases in grazing may jointly play a key role in affecting rangeland carrying capacity.     

航空重力仪的试验

CHZ海洋重力仪1988年装在国产Z-8直升飞机上进行了重力测量试验.在地面上空6个不同的高度上悬停进行重力测量,半小时测定6个高度上的重力.不考虑只悬停一分钟的测点1,则测量精度为±2.3mGal,5个不同高度悬停的归算重力平均值的精度为±1.1mGal,与地面重力值的偏差为-0.4mGal.     

基于GPS/INS的高光谱影像几何粗校正

高光谱影像,较之全色、多光谱影像在地物分类识别方面具有巨大的优势,为了检验现有高光谱相机的空间定位精度,使用基于GPS/INS的POS系统获取航空飞行中高光谱相机的位置与姿态参数,在无地面控制点的情况下,实现几何粗校正.     

一种改进的变权重MRF遥感图像变化检测方法

基于马尔科夫随机场(Markov Random Field,MRF)模型下的遥感图像变化检测因固定组合能量函数导致的边缘分割模糊问题,提出了一种改进的变权重MRF遥感图像变化检测方法。该方法首先通过模糊C均值(Fuzzy C-means,FCM)算法对差值图像进行聚类分割,并依此分割结果作为变权重MRF的初始分割条件进行最终的分割;最后对分割结果进行掩膜处理,得到最终的变化检测结果。采用真实遥感影像进行对比实验,结果表明所提方法变化检测精度更高,边缘检测更加平滑,区域一致性更好。     

基于激光雷达技术在城市三维建筑模型中的分析应用

通过数字城市项目的工程实践,基于激光雷达的三维真实纹理三维模型的建立显得尤为重要,本文着重阐述利用激光雷达技术进行数字城市中三维建筑物建模,使用纹理映射的方法进行模型纹理粘贴。     

基于 Web 数据库的 BDS／GPS 在线资讯及数据处理服务设计与应用

介绍B/S结构下Web数据库及相关内容,基于此提出BDS/GPS在线资讯及数据处理服务,综合新闻资讯与数据处理等多种功能。数据处理采用Bernese及自主开发软件。该服务为用户提供方便直接的数据处理途径,节省用于学习软件及数据下载所需要的时间,并可获得较高精度的处理结果。     

Variability and Long-Term Trend of Total Cloud Cover in China Derived from ISCCP, ERA-40, CRU3, and Ground Station Datasets

Total Cloud Cover (TCC) over China determined from four climate datasets including the International Satellite Cloud Climatology Project (ISCCP), the 40-year Re-Analysis Project of the European Centre for Medium-Range Weather Forecasts (ERA-40), Climate Research Unit Time Series 3.0 (CRU3), and ground station datasets are used to show spatial and temporal variation of TCC and their differences. It is demonstrated that the four datasets show similar spatial pattern and seasonal variation. The maximum value is derived from ISCCP. TCC value in North China derived from ERA-40 is 50% larger than that from the station dataset; however, the value is 50% less than that in South China. The annual TCC of ISCCP, ERA-40, and ground station datasets shows a decreasing trend during 1984-2002; however, an increasing trend is derived from CRU3. The results of this study imply remarkable differences of TCC derived from surface and satellite observations as well as model simulations. The potential effects of these differences on cloud climatology and associated climatic issues should be carefully considered.     

结合序贯指示模拟的贝叶斯高斯混合线性反演

高斯混合模型（Gaussian Mixture Model,GMM）可以用来描述储层性质的多峰分布特性,多峰特性主要是由于它们在不同离散变量内的变化而引起的.在高斯混合模型中,高斯分量的权值代表离散变量的概率.然而,基于高斯混合模型的贝叶斯线性反演可能会对某些点的离散变量错误地分类,进而影响连续变量的反演结果,尤其存在强噪声的时候.在本文中,我们考虑了离散变量的空间变化性,并将高斯混合模型与序贯指示模拟（Sequential Indicator Simulation,SIS）相结合来确定离散变量的后验条件权值,形成了结合序贯指示模拟的贝叶斯高斯混合线性反演方法.该方法能够准确地对离散变量进行归类,且具有良好的抗噪性.通过模型试算,我们证明了这种方法的可行性,并在实际资料中取得了较好的结果.

     

地月空间粒子辐射环境及其对月表物质的影响研究进展

由于没有全球磁场和稠密大气保护,月球直接受宇宙线、太阳风和地球风粒子的轰击.了解月球空间粒子辐射的特性、粒子的来源和传输等过程,本身是亟待解决的空间科学基础问题,同时还可帮助更好地提供预报和预警,为保障探月和载人登月等活动的安全提供理论参考;此外,月球空间辐射环境中的粒子与月表作用产生的水等物质对载人登月和月球基地意义重大,且月表物质保存了空间环境较为完整的信息和演化历史,对研究地月系统及太阳系其他天体(乃至系外行星)的宜居性与演化,也具有重要的科学价值.本文在简要总结地月空间粒子辐射环境研究现状的基础上,重点分析了近月粒子辐射环境及其对月表物质所产生的影响,梳理了宇宙线、太阳能量粒子事件、太阳风、地球风以及月源粒子等不同辐射的来源和传输机制,这些粒子与月表作用产生水、赤铁矿、中性原子等物质的过程,以及相关过程对月球空间环境的影响、对地月系统演化的启示等关键科学问题,并提出了解决问题所面临的技术难点,最后对未来可能的重点研究内容进行了展望,可为后续月球探测任务(例如嫦娥四期和国际月球科研站等)相关领域科技规划提供一定的参考.