海平面升降变化对贵州紫云礁体生长的控制

以贵州紫晚二叠世碳酸盐台地边缘礁为例,运用高频层序地层学原理和方法,精细地划分了紫云礁层序的各级单元,并对其内部沉积构成进行了详细研究,探讨海平面和变化对礁体生长的控制,研究结果表明,晚二叠世紫云礁 合体为发育在台地边缘坡折带的一个三级层序,由１３个准层序组成,并可识别出低位、海侵、高位３个体系域,低位期的下切谷 边缘坡折带碳酸盐台地的暴露、海侵期和高位期礁的３种生长方式的增生及每种生长方式的特定     

淄博煤矿矿坑排水对地表水体的污染及对地下水水质影响的研究

以山东淄博煤田富硫煤（w（St＞2％）煤矿作为典型研究区,阐述了由于直接排放酸性、高SO4离子、高硬度和较高矿化度（TDS）的矿坑水导致的地表水体及地下水的污染。研究区内地表水体的水质主要受控于矿坑排水的质量,区内主要河流、水库已被污染。引用这种受污染的地表水进行灌溉,会引起浅层地下水的严重污染,并影响到饮用此类地下水的人们的身体健康。为揭示污水灌溉过程中水-岩相互作用及地下水污染的机理,进行了现场土柱模拟实验,分别模拟了污水灌溉和降水入渗过程。实验结果表明,污水灌溉过程中SO4-不会被吸附,也不会产生沉淀,因此,污水灌溉是污灌区地下水受污染的主要原因。降水入渗实验表明,污灌区土壤中的SO4-,Ca2+和Mg2+,也可以通过降水淋滤进入地下水,这是污灌区地下水受污染的另一条途径。就对水环境的影响而言,酸性煤矿矿坑排水的环境效应是负面的,应予以高度重视。     

Groundwater storage change detection from in situ and GRACE-based estimates in major river basins across India

ABSTRACT

India has been the subject of many recent groundwater studies due to the rapid depletion of groundwater in large parts of the country. However, few if any of these studies have examined groundwater storage conditions in all of India’s river basins individually. Herein we assess groundwater storage changes in all 22 of India’s major river basins using in situ data from 3420 observation locations for the period 2003–2014. One-month and 12-month standardized precipitation index measures (SPI-1 and SPI-12) indicate fluctuations in the long-term pattern. The Ganges and Brahmaputra basins experienced long-term decreasing trends in precipitation in both 1961–2014 and the study period, 2003–2014. Indeterminate or increasing precipitation trends occurred in other basins. Satellite-based and in situ groundwater storage time series exhibited similar patterns, with increases in most of the basins. However, diminishing groundwater storage (at rates of >0.4 km³/year) was revealed in the Ganges-Brahmaputra River Basin based on in situ observations, which is particularly important due to its agricultural productivity.     

Drought assessment in a south Mediterranean transboundary catchment

ABSTRACT

Predicting the impacts of climate change on water resources remains a challenging task and requires a good understanding of the dynamics of the forcing terms in the past. In this study, the variability of precipitation and drought patterns is studied over the Mediterranean catchment of the Medjerda in Tunisia based on an observed rainfall dataset collected at 41 raingauges during the period 1973–2012. The standardized precipitation index and the aridity index were used to characterize drought variability. Multivariate and geostatistical techniques were further employed to identify the spatial variability of annual rainfall. The results show that the Medjerda is marked by a significant spatio-temporal variability of drought, with varying extreme wet and dry events. Four regions with distinct rainfall regimes are identified by utilizing the K-means cluster analysis. A principal component analysis identifies the variables that are responsible for the relationships between precipitation and drought variability.     

地裂缝场地施工降水对地表沉降和地层应力的影响研究

地裂缝是西安市典型的城市地质灾害，地下水位的变化是诱发地裂缝活动的重要因素。以西安地铁六号线暗挖段施工降水为研究背景，基于有限元数值模拟计算，分析了地裂缝场地施工降水引起的地表沉降规律和地层应力变化特征。计算结果表明:当地下水位下降时，地表沉降量上盘大于下盘，地裂缝带两侧地表存在差异沉降的现象，最大差异沉降量与地下水位下降深度近似呈直线关系；不同位置处地表的横向沉降呈现出"Z"形的变化特征，差异沉降区随地裂缝位置的变动而变化，且差异沉降量与横向地表位置近似呈二次函数曲线关系；地层竖向应力随着地下水位下降而增大，地裂缝位置处地层应力存在突变现象，上下盘应力影响区与地层深度近似呈三次函数曲线关系；基于分层总和法计算了地下水位下降时地表沉降量的解析解，并与数值模拟结果进行对比，发现两种方法计算结果基本一致，得到了计算地表最大沉降量的经验公式。研究结果可为地裂缝场地地铁隧道及其他地下工程安全施工提供科学指导。      

酒泉、嘉峪关地域城镇系统的空间规模结构研究

受干旱区自然地理、人口发展与分布等特殊条件的制约,酒泉、嘉峪关地域城镇系统的空间规模结构呈现“中小市镇、多中心”的特征。针对这种状况,空间规模结构的研究和规划,应注重建构多中心的地域城镇系统,带动地域整体发展要促进相邻城市间、城市与境内或周边单位间的空间关联及与近郊集镇的融合,推动城乡一体化应突出酒泉-嘉峪关复合城市的中心地位,强化敦煌市的规模和职能,保证玉门市区持续发展并尽快发展玉门镇,积极发展其他小城镇。     

Multi-scale remote sensing to support insurance policies in agriculture: from mid-term to instantaneous deductions

ABSTRACT

Climate change is today one of the biggest issues for farmers. The increasing number of natural disasters and change of seasonal trends is making insurance companies more interested in new technologies that can somehow support them in quantifying and mapping risks. Remotely sensed data, with special focus on free ones, can certainly provide the most of information they need, making possible to better calibrate insurance fees in space and time. In this work, a prototype of service based on free remotely sensed data is proposed with the aim of supporting insurance companies’ strategies. The service is thought to calibrate annual insurance rates, longing for their reduction at such level that new customers could be attracted. The study moves from the entire Piemonte region (NW Italy), to specifically focus onto the Cuneo province (Southern Piemonte), which is mainly devoted to agriculture. MODIS MOD13Q1-v6 and Sentinel-2 L2A image time series were jointly used. NDVI maps from MODIS data were useful to describe the midterm phenological trends of main crops at regional level in the period 2000–2018; differently, Sentinel-2 data permitted to map local crop differences at field level in 2016 and 2017 years. With reference to MODIS data, the average phenological behavior of main crop classes in the area, obtained from the CORINE Land Cover map Level 3, was considered using a time series decomposition approach. Trend analyses showed that the most of the crop classes alternated three phases (about 7 years) suggesting that, presently, this is probably the time horizon to be considered to tune mid-term algorithms for risk estimates in the agricultural context. Crop classes trends were consequently split into three phases and each of them modeled by a first-order polynomial function used to update correspondent insurance risk rate. Sentinel-2 data were used to map phenological anomalies at field level for the 2016 and 2017 growing seasons; shifts from class average behavior were considered to locally and temporarily tune insurance premium around its average trend as described at the previous step. Synthesizing, one can say that this approach, integrating MODIS and Sentnel-2 data, makes possible to locally and temporarily calibrate premiums of indexed insurance policies by describing the average trends of crop performance (NDVI) at regional level by MODIS data and refining it at field and specific crop level by Sentinel-2 data.     

江淮梅雨与东亚副热带夏季风进程变异的关系

根据中国气象局《梅雨监测业务规定》中的入、出梅标准,结合1960—2016年全国661个常规气象站逐日气象资料,以及NCEP/NCAR月平均再分析资料,分析了江淮梅雨和东亚副热带夏季风进程变异的时空特征,提取季风关键区(32°~34°N,112°~120°E,包含17个站点),并分析了江淮梅雨和季风关键区的联系与成因。结果表明:1960—2016年平均梅雨期为6月8日—7月15日,平均梅雨量为303 mm。比东亚平均梅雨季的开始时间早9 d,比其结束时间晚7 d。梅雨量在近57 a中也呈波动式变化,但整体为上升趋势。入梅越早,出梅越晚,则梅雨期越长,梅雨量越多。副热带夏季风推进到关键区的平均时间为5月19日,其在1970s末和1990s末分别发生了由偏晚向偏早和由偏早向偏晚的突变。夏季风到达关键区偏早时,出梅日偏晚,梅雨量偏多,季风到达偏晚时,出梅日偏早,梅雨量偏少。副热带夏季风推进时间和江淮梅雨量呈全区一致的负相关,负相关区位于湖南、湖北及江西三省临近的两湖地区。东亚副热带夏季风到达关键区时间偏早(晚)年,500 hPa高度场上乌拉尔山—鄂霍茨克海为正(负)距平,阻塞高压增强(减弱);日本海附近为负(正)距平,东亚大槽加深(西退北缩),加强(削弱)了槽后冷空气向南输送且不(有)利于中低纬度副热带高压的北跳,西太平洋副热带高压中心强度增强(减弱),位置偏西(东),其西北侧的西南暖湿气流输送加强(减弱),江淮地区有水汽的辐合(辐散),有(不)利于梅雨量偏多。     

GPM卫星降水数据在沿海地区的适用性分析——以三亚市为例

选取2016年1—12月GPM(Global Precipitation Measurement)卫星的IMERG月尺度降水数据为研究对象,以同时期的气象站点实测降水数据为参考,利用相关系数、标准偏差、相对误差等多种统计分析指标对其在沿海地区估测能力进行评价。结果表明:IMERG月尺度降水量与站点实测降水数据相关性较好,IMERG估测的降水与气象站点实测降水量的时空变化规律也较为一致,但是量化到具体数值而言,其对山区、海岛站的估测能力不及地势平坦的区域;同时,选取降水个例对IMERG日尺度和半小时尺度降水数据的分析表明,日尺度IMERG估测的不同等级降水量也存在偏差,半小时尺度IMERG降水数据对海岛站的降水估测偏高。总体而言,IMERG降水数据对降水的时间变化规律和空间分布格局估测较为合理,但是对山区、海岛地区,其降水估测值还存在偏差,在今后应用中需结合地形特征加以合理利用。     

中国近代金矿开发概貌

总结了我国清末至民国初期(1840—1920年)长达80年的金矿开发概貌,按现行政区划,共涉及21个省。对各省的金矿,既扼要探讨历史沿革,又尽量地汇集具体产金地名及有关地质矿产信息,期望达到治史与古为今用相结合的双重目的。