An Analysis of Programs Managed by Division of Geography,Department of Earth Sciences,National Natural Science Foundation of China     

Zhang Chaolin  Zheng Yuanming  Fan Wenjie  Shen Xiangjin  Zhang Jing  Ta Na  Peng Shuangyun 《地球科学进展》2018,33(12):1272-1281

  相似文献   

北京市地面沉降分布及典型灾害类型初探     

赵龙  武增宽  李玉梅  罗勇  沙特  刘贺  田苗壮  孔祥如 《城市地质》2018,(2):51-56

地面沉降为北京主要次生地质灾害之一,近年来呈现快速发展趋势,对城市规划发展和经济建设的影响日趋明显。目前对于北京地面沉降灾害类型及特征认识较为局限,缺乏全面、系统认识。本文通过区域水准测量监测数据及以往调查资料的搜集整理,结合现场调查,阐明了北京地面沉降分布特征,总结归纳了地面沉降灾害类型及特征,发现区域性地面沉降形成的以井管抬升为代表的点状破坏现象,该类灾害以点为中心呈辐射状分布,影响范围较小。局部差异沉降形成包括墙体开裂、地表开裂及桥梁开裂等具有线状破坏形式的灾害,该类灾害多呈线性沿固定方向延伸,影响范围较大。  相似文献   

滇西双江县勐库地区临沧花岗岩中暗色包体锆石U-Pb年代学及其地质意义          下载免费PDF全文

曾文涛  孙载波  周坤  吴嘉林  黄亮  赵江泰 《沉积与特提斯地质》2018,38(1):23-36

位于三江南段双江勐库地区的临沧花岗岩,主体岩性为黑云母二长花岗岩,其次为黑云母花岗闪长岩和碱长花岗岩。通过野外地质调查,在勐库热水塘附近黑云二长花岗岩中发现了与其紧密共生的暗色镁铁质微粒包体(MME)—闪长岩。本文对暗色闪长岩包体进行了岩相学观察、LA-ICP-MS锆石U-Pb定年和全岩主量元素分析。暗色闪长岩包体LA-ICP-MS锆石U-Pb年龄为230.9±1.2Ma,与中细粒黑云二长花岗岩LA-ICP-MS锆石U-Pb年龄(229.2±0.8Ma)基本一致。岩石地球化学特征表明,黑云二长花岗岩富K2O和Na2O,Na2OK2O,富Al2O3,铝饱和指数A/CNK平均为1.17;闪长岩K2O和Na2O含量中等,Na2OK2O,富Al2O3和Mg O,铝饱和指数A/CNK平均为0.77。二者稀土配分曲线为右倾的轻稀土富集型,二者均富集大离子亲石元素而亏损高场强元素Nb、Ta等,均具有相对较高的Mg#(黑云二长花岗岩30.50~61.41;闪长岩58.58~67.34)。中细粒黑云二长花岗岩Cr、Ni含量(平均值分别为46.96×10-6和11.21×10-6)小于闪长岩Cr、Ni含量(平均值分别为197.62×10-6和75.68×10-6)。综合研究表明,该地区花岗质岩浆的形成很可能与地幔流体作用引发的地壳部分熔融与壳幔岩浆混合作用密切相关,形成于陆陆碰撞-后碰撞的构造背景,暗示保山地块与思茅地块在230Ma已经进入了陆陆碰撞-后碰撞的地质时期。  相似文献   

IPCC AR6报告解读：地球能量收支、气候反馈和气候敏感度     

张华  王菲  赵树云  谢冰 《气候变化研究进展》2021,17(6):691-698

文中对IPCC第六次评估报告（AR6）第一工作组（WGI）报告的第七章关于地球能量收支、气候反馈和气候敏感度中的重要内容进行了凝练,并简要总结该方面的最新研究成果和结论。评估显示,自工业革命以来,人类活动造成的有效辐射强迫（ERF）为2.72 [1.96~3.48] W/m²,其中,均匀混合温室气体的贡献为3.32 [3.03~3.61] W/m²,气溶胶的贡献为-1.1 [-1.7~-0.4] W/m²。净的气候反馈参数为-1.16 [-1.81~-0.51] W/(m²∙℃),云仍然是气候反馈整体不确定性的最大来源。平衡态气候敏感度（ECS）和瞬态气候响应（TCR）可用于评估全球平均地表气温对强迫的响应,是衡量全球气候响应的有效手段。ECS和TCR的最佳估计分别为3.0 [2.0~5.0]℃和1.8 [1.2~2.4]℃。  相似文献   

Satellite estimates and subpixel variability of rainfall in a semi-arid grassland          下载免费PDF全文

Yong Chen  Jing Duan  Junling An  Huizhi Liu  Ulrich G?rsdorf  Franz H.Berger 《大气和海洋科学快报》2021,14(5):24-29

卫星估雨精度的不确定性受到当地降雨类型和像元内降雨非均匀性影响,而结合这两个关键因素开展半干旱草原卫星估雨的研究有限.2009年夏,我们在中国锡林郭勒半干旱草原用多部微雨雷达和雨量计构建了9 km卫星像元降雨观测网,观测了像元内降雨非均匀性(空间变异系数CV),并评估了卫星估雨精度.结果表明:(1)CV值受像元内平均降雨量,降雨类型,降雨云面积及移向等影响,如高Cv值的降雨过程大多为平均降雨量小,对流性降雨过程,降雨云边缘像元CV值较高;(2)TRMM 3B42V7卫星估雨产品适用性较好,CMORPH和PERSIANN次之,但TRMM 3B42V7易在半干旱草原湖泊处高估降雨.  相似文献   

The Key Supply Source of Long-Distance Moisture Transport for the Extreme Rainfall Event on July 21, 2012 in Beijing     

李娟  徐祥德  李跃清  赵天良  吴翀 《热带气象学报(英文版)》2021,27(1):34-47

In this study, the Weather Research and Forecasting (WRF) model and meteorological observation data were used to research the long-distance moisture transport supply source of the extreme rainfall event that occurred on July 21, 2012 in Beijing. Recording a maximum rainfall amount of 460 mm in 24 h, this rainstorm event had two dominant moisture transport channels. In the early stage of the rainstorm, the first channel comprised southwesterly monsoonal moisture from the Bay of Bengal (BOB) that was directly transported to north China along the eastern edge of Tibetan Plateau (TP) by orographic uplift. During the rainstorm, the southwesterly moisture transport was weakened by the transfer of Typhoon Vicente. Moreover, the southeasterly moisture transport between the typhoon and western Pacific subtropical high (WPSH) became another dominant moisture transport channel. The moisture in the lower troposphere was mainly associated with the southeasterly moisture transport from the South China Sea and the East China Sea, and the moisture in the middle troposphere was mainly transported from the BOB and Indian Ocean. The control experiment well reproduced the distribution and intensity of rainfall and moisture transport. By comparing the control and three sensitivity experiments, we found that the moisture transported from Typhoon Vicente and a tropical cyclone in the BOB both significantly affected this extreme rainfall event. After Typhoon Vicente was removed in a sensitivity experiment, the maximum 24-h accumulated rainfall in north China was reduced by approximately 50% compared with that of the control experiment, while the rainfall after removing the tropical cyclone was reduced by 30%. When both the typhoon and tropical cyclone were removed, the southwesterly moisture transport was enhanced. Moreover, the sensitivity experiment of removing Typhoon Vicente also weakened the tropical cyclone in the BOB. Thus, the moisture pump driven by Typhoon Vicente played an important role in maintaining and strengthening the tropical cyclone in the BOB through its westerly airflow. Typhoon Vicente was not only the moisture transfer source for the southwesterly monsoonal moisture but also affected the tropical cyclone in the BOB, which was a key supply source of long-distance moisture transport for the extreme rainfall event on July 21, 2012 in Beijing.  相似文献   

A CRPS-Based Spatial Technique for the Verification of Ensemble Precipitation Forecasts     

赵滨  张博  李子良 《热带气象学报(英文版)》2021,27(1):24-33

Traditional precipitation skill scores are affected by the well-known“double penalty”problem caused by the slight spatial or temporal mismatches between forecasts and observations. The fuzzy (neighborhood) method has been proposed for deterministic simulations and shown some ability to solve this problem. The increasing resolution of ensemble forecasts of precipitation means that they now have similar problems as deterministic forecasts. We developed an ensemble precipitation verification skill score, i.e., the Spatial Continuous Ranked Probability Score (SCRPS), and used it to extend spatial verification from deterministic into ensemble forecasts. The SCRPS is a spatial technique based on the Continuous Ranked Probability Score (CRPS) and the fuzzy method. A fast binomial random variation generator was used to obtain random indexes based on the climatological mean observed frequency, which were then used in the reference score to calculate the skill score of the SCRPS. The verification results obtained using daily forecast products from the ECMWF ensemble forecasts and quantitative precipitation estimation products from the OPERA datasets during June-August 2018 shows that the spatial score is not affected by the number of ensemble forecast members and that a consistent assessment can be obtained. The score can reflect the performance of ensemble forecasts in modeling precipitation and thus can be widely used.  相似文献   

TLS技术在环境地质灾害监测中的应用进展   总被引：2，自引：1，他引：1  

杜超  赵进  任宪友  张亮  庄艳华 《测绘科学》2018,(6):65-71,105

针对地面三维激光扫描技术在环境地质灾害监测中的应用问题,该文在系统介绍此技术关键指标和数据处理的基础上,从滑坡监测、土壤侵蚀监测、敏感地貌微变形监测和水灾害边界追踪4个方面,详细介绍了该技术在环境地质灾害监测领域的应用历史和现状,其研究热点包括该技术在应用中的适宜性评价、监测精度评价、滤波算法的开发及灾害发生趋势预判等方面。另外,应用中高植被覆盖度和降雨天气的干扰问题可通过继续优化软硬件并加强与其他技术联合应用予以弥补。  相似文献   

陆态网络GNSS基准站地壳运动速度场分析     

马下平  赵立都 《测绘科学》2018,(8):1-6

针对中国大陆构造环境监测网络(陆态网络)中观测数据处理的期数过少或解算成果的坐标系统不统一等问题,该文在ITRF2008中对陆态网络239个GNSS基准站从2010年1月至2013年8月的观测数据进行解算,获取站点的坐标时间序列,估计了站点的水平和垂直运动速度场,并分析了中国大陆地壳运动特征。结果表明:GNSS基准站在ITRF2008中的坐标时间序列整体上符合线性变化趋势,东西方向的幅度变化大,高程方向受观测噪声的影响较大一些;高程方向相比较水平方向的年周期性更为明显;水平速度场明显有自西向东运动的趋势,且西藏块体中测站变化最为明显;垂直运动速度场中,华中、华南、华东块体中测站存在较低速率的下降,其他块体的测站存在较低速率的隆升。  相似文献   

校正地基摄影获取树枝倾角     

李雷  孟治国  郑兴明  赵凯  李晓洁  李晓峰 《测绘科学》2018,(5):109-114

针对传统树枝倾角测量方法的复杂性和精度低的问题,该文提出了通过校正地基摄影获取树枝倾角的方法。基于投影变换和小孔成像原理,通过自制树枝模型的方法,分析了直接图上量取树枝倾角与真实值之间误差的成因,提出了基于投影变化的树枝倾角计算公式。结果表明:该研究获取树枝倾角的相对误差2.72%明显优于传统测量的31.33%,同时随拍摄距离变化,树枝倾角估算结果具有稳定性。该研究方法简单、有效,非常适合复杂环境下树枝倾角的大量提取,并提出了一种基于摄影成像原理获取树枝倾角的方法,发展了树枝倾角测量系统软件,提高测量精度并降低了测量难度。  相似文献