井地磁测资料联合反演及应用

井中磁测离深部场源近,能避开浅部干扰,是一种有效的找矿手段,但其控制范围有限;地面磁测采集方便且控制范围大,但老矿区干扰因素多,深部矿体信号弱,不容易解释.文章充分利用地面和井中磁测资料的优点,以二度板状体模型为例,进行井地磁测资料联合反演.通过数值模拟说明了井地联合反演方法的优越性,同时还比较了马奎特法,广义逆法和遗传算法三种不同算法的优缺点,最后将其应用于大冶铁矿实际资料的处理解释,为危机矿山的深部找矿提供了一种有效的方法.     

Uncertainties in historical changes and future projections of drought. Part II: model-simulated historical and future drought changes

While most models project large increases in agricultural drought frequency and severity in the 21st century, significant uncertainties exist in these projections. Here, we compare the model-simulated changes with observation-based estimates since 1900 and examine model projections from both the Coupled Model Inter-comparison Project Phase 3 (CMIP3) and Phase 5 (CMIP5). We use the self-calibrated Palmer Drought Severity Index with the Penman-Monteith potential evapotranspiration (PET) (sc_PDSI_pm) as a measure of agricultural drought. Results show that estimated long-term changes in global and hemispheric drought areas from 1900 to 2014 are consistent with the CMIP3 and CMIP5 model-simulated response to historical greenhouse gases and other external forcing, with the short-term variations within the model spread of internal variability, despite that regional changes are still dominated by internal variability. Both the CMIP3 and CMIP5 models project continued increases (by 50–200 % in a relative sense) in the 21st century in global agricultural drought frequency and area even under low-moderate emissions scenarios, resulting from a decrease in the mean and flattening of the probability distribution functions (PDFs) of the sc_PDSI_pm. This flattening is especially pronounced over the Northern Hemisphere land, leading to increased drought frequency even over areas with increasing sc_PDSI_pm. Large differences exist in the CMIP3 and CMIP5 model-projected precipitation and drought changes over the Sahel and northern Australia due to uncertainties in simulating the African Inter-tropical convergence zone (ITCZ) and the subsidence zone over northern Australia, while the wetting trend over East Africa reflects a robust response of the Indian Ocean ITCZ seen in both the CMIP3 and CMIP5 models. While warming-induced PET increases over all latitudes and precipitation decreases over subtropical land are responsible for mean sc_PDSI_pm decreases, the exact cause of its PDF flattening needs further investigation.     

大众休闲背景下展览展示类文化空间公众感知价值研究--基于广州市中心城区场馆个案的调查

公共文化空间感知价值是评测公众对其使用的文化设施及其环境和服务等感知体验的重要手段。在梳理相关研究的基础上,立足于大众休闲的时代背景,运用描述性统计和因子分析法,从顾客体验的角度,对广州市中心城区展览展示类公共文化空间中具有代表性的博物馆、纪念馆、美术馆等8个场馆进行调查,分析和提取公众体验感知价值维度和构建感知价值评价体系。研究发现展览展示类公共文化空间感知价值评价体系由9个维度(场馆价值、成本价值、人员服务价值、辅助设施价值、资源品质价值、休闲价值、配套服务价值、基础设施价值、资源管理价值)和38个评价细项构成。通过重要性-绩效分析(IPA)方法,找出公众对展览展示类公共文化空间感知价值评价因子的期望与绩效表现的差异,客观评价广州市中心城区文化场馆服务绩效,并得出研究结论和建议。     

坦桑尼亚人口分布空间格局及演变特征

坦桑尼亚是中国“一带一路”战略的重要辐射点,中国已成为坦桑尼亚第一大贸易伙伴。本文基于坦桑尼亚全国人口普查资料及分地区统计数据,运用人口密度分析法、人口分布集中指数、人口重心模型和人口偏移增长模型,分析了坦桑尼亚自20世纪80年代末经济变革以来人口分布的空间格局及演变特征。研究结果表明：①坦桑尼亚人口分布以中央铁路线为界,呈现“南疏北密”特征;②1988-2002-2012年间,人口分布不均衡发展的态势不断增强,人口分布重心始终处于中部偏北地区,且有继续北移的趋势;③人口向城市地区集聚是人口再分布的主要过程,中心城市的人口集聚能力不断增强,达累斯萨拉姆省始终处于正向增长的绝对优势地位,以致周边地区出现明显的人口偏移负增长;④铁路和港口等基础设施对人口集聚的作用明显。上述结论对中坦在基础设施建设、住房建设及公共服务方面的合作具有重要意义。     

内蒙古大兴安岭林区极端气温事件变化特征

利用内蒙古大兴安岭林区11个气象站1971~2014年日平均气温数据,采用线性趋势、Morlet小波分析、克里金插值法对内蒙古大兴安岭林区极端气温的年变化进行分析。研究表明：极端高温天气和生物生长季天数在20世纪80年代中期以后呈显著增多趋势,极端低温天气呈显著减少趋势;在空间分布上,所有站点极端高温天气和生物生长季天数呈上升趋势,极端低温天气呈下降趋势,但空间差异明显。极端低温天气主要受27、18、11、7 a时间尺度周期影响。极端高温天气28 a左右周期振荡最为强烈,视为第一主周期,对极端高温天气影响最为显著,在2018年以后的大约8 a间（2019~2026年）极端高温天气可能会更加频繁。生物生长季受28 a时间尺度周期影响,且在2015~2022年生物生长季天数增长处于偏大期。     

Modelling the integrated effects of land use and climate change scenarios on forest ecosystem aboveground biomass,a case study in Taihe County of China

Global and regional environmental changes such as land use and climate change have significantly integrated and interactive effects on forest. These integrated effects will undoubtedly alter the distribution, function and succession processes of forest ecosystems. In order to adapt to these changes, it is necessary to understand their individual and integrated effects. In this study, we proposed a framework by using coupling models to gain a better understanding of the complex ecological processes. We combined an agent-based model for land use and land cover change (ABM/LUCC), an ecosystem process model (PnET-II), and a forest dynamic landscape model (LANDIS-II) to simulate the change of forest aboveground biomass (AGB) which was driven by land use and climate change factors for the period of 2010–2050 in Taihe County of southern China, where subtropical coniferous plantations dominate. We conducted a series of land use and climate change scenarios to compare the differences in forest AGB. The results show that: (1) land use, including town expansion, deforestation and forest conversion and climate change are likely to influence forest AGB in the near future in Taihe County. (2) Though climate change will make a good contribution to an increase in forest AGB, land use change can result in a rapid decrease in the forest AGB and play a vital role in the integrated simulation. The forest AGB under the integrated scenario decreased by 53.7% (RCP2.6 + land use), 57.2% (RCP4.5 + land use), and 56.9% (RCP8.5 + land use) by 2050, which is in comparison to the results under separate RCPs without land use disturbance. (3) The framework can offer a coupled method to better understand the complex and interactive ecological processes, which may provide some supports for adapting to land use and climate change, improving and optimizing plantation structure and function, and developing measures for sustainable forest management.     

人地关系地域系统与可持续发展的相互作用机理初探

地理学研究的核心为人地关系地域系统。人地关系理论的研究与实践操作对可持续发展的内涵认知有着举足轻重的影响。同时,人地系统本身也必须得到发展,这样才能促进可持续发展内涵的丰富化与哲理化。在当代世界范围内的可持续发展思想的困惑越来越多的情况下,研究了人地关系地域系统和可持续发展系统的相互作用机理,探讨了人地系统的发展本质、可持续发展的本质、人地协调发展的时空背景、二者相互作用机理的哲学本质等问题     

我国杭州地区秋和稻田的甲烷排放

1987年秋季在杭州郊区采用一套全自动的观测系统,对稻田的甲烷排放进行了观测。在整个晚稻灌溉期内,稻田是大气甲烷的一个源地,其甲烷释放率最高可达240mg/m~2·h。甲烷释放率具有很强的季节性变化,在水稻成熟期之前,甲烷释放率一般在40-60mg·CH_4/m~2·h的水平上波动,在成熟期间则降为10mg·CH_4/m~2·h的水平。除移栽期外的整个水稻生长期间的甲烷平均释放率为39mg/m~2·h。甲烷释放率具有明显的日变化,一般在午夜至凌晨3—4点达最大值,白天较低,变化也较小。这可能与水稻植物体由于其生理上的日变化引起的甲烷气体传输能力的日变化有关。实验没有观测到不同施肥(K_2SO_4和菜饼)对甲烷释放率的明显影响。阴雨天的降温一般在2—3天后引起甲烷释放率的迅速下降,这可能是因土壤中发酵细菌如产甲烷菌数量的减少造成的。尽管甲烷释放率和土壤温度在整个生长期间基本上是逐步下降的,但两者之间并没有简单的正相关性。土壤中产生的甲烷气体只有一小部分释放到大气中,从土壤中冒出来的气泡往往可引起释放率的急剧上升。1985年全球稻田的甲烷释放量估计为134±3lTg(1Tg=10~(12)g),其中12±26Tg和30±6Tg分别来自亚太地区和中国稻田。     

荷泽5.9级地震前小震波速比时空变化特征

本文研究了荷泽5.9级地震前小震波速比时空变化特征,发现在荷泽附近大约2°×2°范围内出现了持续两年的小震波速比低值异常集中分布区,当集中区内波速比回升到极大值后小震活动平静,然后波速比低值区向外围扩散,当外围出现波速比极小值且逐渐回升后,在低值集中区内主震发生。震前小震波速比低值异常持续三年,直到主震前半个月波速比恢复正常。最后本文对波速比异常的有关问题进行了讨论。     

辽宁盖县猫岭金矿床毒砂的矿物学研究及成因意义

盖县猫岭金矿床以毒砂和磁黄铁矿为主.毒砂可划分为大颗粒毒砂、细脉状及毒砂石英脉中的毒砂和细粒浸染状毒砂三种性状.毒砂与金矿化密切相关.化学分析结果表明,矿区毒砂为“硫”毒砂,形成于中低温条件、中深部位.毒砂中δ~(34)S值同辽河群的δ~(34)S相一致,表明毒砂中的硫来源于辽河群.毒砂矿物标型特征指示矿床成因