Rescaling of Access and Property Relations in a Frontier Landscape: Insights from Jambi,Indonesia

The recent expansion of protected areas and oil palm plantations in Jambi (Sumatra), Indonesia, has been notably disruptive. This article investigates the scalar dimensions of land conflicts within a privately managed conservation area. We built on qualitative research focusing on struggles related to the formation of two informal settlements within the conservation area. Results indicate that, especially in the context of rapid rescaling (e.g., decentralization), new power constellations emerge, thereby altering preexisting property relations. We argue that competing scales of meaning and regulation are structuring the ability of actors to access land and, consequently, reflect tensions between structure and agency.     

土地集约利用数据库实时更新系统的研制

针对PDA产品信息采集不全、屏幕小不易图形编辑、维护保管难及数据库更新不及时等问题,文章将更新数据的编辑、审核和更新入库功能移至服务器端。在系统结构设计、数据库设计以及功能设计等基础上,利用组件式GIS开发、空间数据拓扑分析、软件系统集成、地理建模等先进技术,对土地集约利用数据库实时更新系统进行开发,实现了土地集约利用评价数据库采集和更新内外业一体化,进而实现与"土地集约利用终端系统"的完美对接,为土地集约利用评价系统提供了实时、准确的数据源。     

天水盆地新近纪伸展构造——来自沉积与构造变形方面的证据

天水盆地位于青藏高原东北缘高海拔挤压隆升区与鄂尔多斯低海拔伸展区的过渡部位,新构造活动强烈。然而,新构造活动对天水盆地的影响尚不清楚。通过对盆地的沉积环境、构造沉降、构造变形等方面的研究,结果显示:1盆地由风成堆积、洪积扇、河湖相与湖泊相沉积组成,代表沉积中心的河湖相与湖泊相沿控盆断裂(西秦岭北缘断裂、西和断裂与礼县-罗家堡断裂)分布;2盆地经历了16~14Ma、9.2~7.4Ma和3.6~2.6Ma三次加速沉降期;3控盆断裂在同沉积期为正断层。沉积中心沿断裂分布、快速沉降事件及生长正断层表明,天水盆地至少在中新世晚期受控于走滑伸展构造,记录了青藏高原向北东方向的构造挤出作用。     

Tectono–Thermal Evolution, Hydrocarbon Filling and Accumulation Phases of the Hari Sag, in the Yingen–Ejinaqi Basin, Inner Mongolia, Northern China

This work restored the erosion thickness of the top surface of each Cretaceous formations penetrated by the typical well in the Hari sag, and simulated the subsidence burial history of this well with software BasinMod. It is firstly pointed out that the tectonic subsidence evolution of the Hari sag since the Cretaceous can be divided into four phases: initial subsidence phase, rapid subsidence phase,uplift and erosion phase, and stable slow subsidence phase. A detailed reconstruction of the tectonothermal evolution and hydrocarbon generation histories of typical well was undertaken using the EASY R_0% model, which is constrained by vitrinite reflectance(R_0) and homogenization temperatures of fluid inclusions. In the rapid subsidence phase, the peak period of hydrocarbon generation was reached at c.a.105.59 Ma with the increasing thermal evolution degree. A concomitant rapid increase in paleotemperatures occurred and reached a maximum geothermal gradient of about 43-45℃/km. The main hydrocarbon generation period ensued around 105.59-80.00 Ma and the greatest buried depth of the Hari sag was reached at c.a. 80.00 Ma, when the maximum paleo-temperature was over 180℃.Subsequently, the sag entered an uplift and erosion phase followed by a stable slow subsidence phase during which the temperature gradient, thermal evolution, and hydrocarbon generation decreased gradually. The hydrocarbon accumulation period was discussed based on homogenization temperatures of inclusions and it is believed that two periods of rapid hydrocarbon accumulation events occurred during the Cretaceous rapid subsidence phase. The first accumulation period observed in the Bayingebi Formation(K_1 b) occurred primarily around 105.59-103.50 Ma with temperatures of 125-150℃. The second accumulation period observed in the Suhongtu Formation(K_1 s) occurred primarily around84.00-80.00 Ma with temperatures of 120-130℃. The second is the major accumulation period, and the accumulation mainly occurred in the Late Cretaceous. The hydrocarbon accumulation process was comprehensively controlled by tectono-thermal evolution and hydrocarbon generation history. During the rapid subsidence phase, the paleo temperature and geothermal gradient increased rapidly and resulted in increasing thermal evolution extending into the peak period of hydrocarbon generation,which is the key reason for hydrocarbon filling and accumulation.     

重度石漠化区不同土地利用方式下土壤养分特征

本文以云南省蒙自市西北勒乡碧色寨村石漠化土地为研究对象,基于主成分分析法（PCA）研究岩溶石漠化区不同土地利用方式下的土壤养分特征。结果表明:（1）研究区土壤各养分指标变异系数介于0.14~1.76,不同土地利用方式下,土壤养分状况有较大差异;（2）研究区土壤12项养分指标可归结为3个主成分,所提供的信息占全部信息的90.69%,其中PC1主要包含了全磷、有效磷、速效钾和有效锰,PC2主要综合了有机碳、全氮、全钙和有效锌,有效铁对PC3具有较大的贡献。（3）对不同用地类型土壤养分的主成分得分进行排序,由大到小依次为火龙果地>林地>封育草地>玉米地,表明植树造林及火龙果种植等方式能有效改善石漠化区的土壤养分状况。建议对样区的石漠化治理应以封山育土为前提,以生态恢复为目的,通过种植火龙果与修复林地改善样区土壤状况,逐步形成生态环境与社会经济协调发展的石漠化综合治理体系。      

Spatio-temporal Distribution of Three Kinds of Flash Droughts over Agricultural Land in China from 1983 to 2015

At present, flash drought occurs globally and regionally and causes a lot of socio-economic loss in a very short time. Therefore, flash drought has been regarded as one of the hottest issues in drought research. However, flash drought monitoring, prediction and decision-making have encountered a lot of challenges due to its multiple driven factors and complex spatio-temporal process. Aiming at this problem, this paper focused on the agricultural land in China, and analyzed the spatio-temporal distribution of three kinds of flash droughts (i.e., precipitation-deficit, high-temperature, and composite flash droughts) from 1983 to 2015. We studied the occurrences, duration, spatial distribution, temporal distribution, and trend of all three kinds of flash droughts. Our results demonstrated that, the occurrences of flash drought agricultural land in China increased year by year, among which high-temperature flash drought increased dramatically; duration of flash droughts had different trends, but the variations were relatively smooth; Northeast China was identified as a vulnerable area of flash drought, indicating more flash drought events and longer duration; flash droughts in China were found to concentrate in spring (high-temperature drought) and summer seasons (precipitation-deficit drought). This study is helpful for building new flash drought monitoring method and system, and it is also valuable for flash drought preparedness on regional scale.     

A model for integrated spatial land use characteristics linking to surface nutrient concentration

Quantifying land use heterogeneity helps better understand how it influences biophysical systems. Land use area proportions have been used conventionally to predict water quality variables. Lacking an insight into the combined effect of various spatial characteristics could lead to the statistical bias and confused understanding in previous studies. In this study, using spatial techniques and mathematical models, a diagnostic model was developed and applied for quantifying and incorporating three spatial components, namely, slope, distance to sampling spots, and arrangement. The upper catchment of Miyun Reservoir was studied as the test area. Total nitrogen, total phosphorus, and chemical oxygen demand of water samples from field measurements were used to characterize the surface water quality in 52 sub-watersheds. Using parameter calibrations and determinations, combined spatial characteristics were explored and detected. Adjusted land use proportions were calculated by spatial weights of discriminating the relative contribution of each location to water quality and used to build the integrated models. Compared with traditional methods only using area proportions, our model increased the explanatory power of land use and quantified the effects of spatial information on water quality. This can guide the optimization of land use configuration to control water eutrophication.     

Subsidence in the Kathmandu Basin,before and after the 2015 Mw 7.8 Gorkha Earthquake,Nepal Revealed from Small Baseline Subset-DInSAR Analysis

Land subsidence in densely urbanized areas is a global problem that is primarily caused by excessive groundwater withdrawal. The Kathmandu Basin is one such area where subsidence due to groundwater depletion has been a major problem in recent years. Moreover, on 25 April 2015, this basin experienced large crustal movements caused by the Gorkha earthquake (Mw 7.8). Consequently, the effects of earthquake-induced deformation could affect the temporal and spatial nature of anthropogenic subsidence in the basin. However, this effect has not yet been fully studied. In this paper, we applied the SBAS-DInSAR technique to estimate the spatiotemporal displacement of land subsidence in the Kathmandu Basin before and after the Gorkha earthquake, using 16 ALOS-1 Phased Array L-band Synthetic Aperture Radar (PALSAR) images during the pre-seismic period and 26 Sentinel-1 A/B SAR images during the pre- and post-seismic periods. The results showed that the mean subsidence rate in the central part of the basin was about ?8.2 cm/year before the earthquake. The spatial extents of the subsiding areas were well-correlated with the spatial distributions of the compressible clay layers in the basin. We infer from time-series InSAR analysis that subsidence in the Kathmandu basin could be associated with fluvio-lacustrine (clay) deposits and local hydrogeological conditions. However, after the mainshock, the subsidence rate significantly increased to ?15 and ?12 cm/year during early post-seismic (108 days) and post-seismic (2015–2016) period, respectively. Based on a spatial analysis of the subsidence rate map, the entire basin uplifted during the co-seismic period has started to subside and become stable during the early-post-seismic period. This is because of the elastic rebound of co-seismic deformation. However, interestingly, the localized areas show increased subsidence rates during both the early-post- and post-seismic periods. Therefore, we believe that the large co-seismic deformation experienced in this basin might induce the local subsidence to increase in rate, caused by oscillations of the water table level in the clay layer.     

Dynamic land use change simulation using cellular automata with spatially nonstationary transition rules

The dynamic relationships between land use change and its driving forces vary spatially and can be identified by geographically weighted regression (GWR). We present a novel cellular automata (GWR-CA) model that incorporates GWR-derived spatially varying relationships to simulate land use change. Our GWR-CA model is characterized by spatially nonstationary transition rules that fully address local interactions in land use change. More importantly, each driving factor in our GWR model contains effects that both promote and resist land use change. We applied GWR-CA to simulate rapid land use change in Suzhou City on the Yangtze River Delta from 2000 to 2015. The GWR coefficients were visualized to highlight their spatial patterns and local variation, which are closely associated with their effects on land use change. The transition rules indicate low land conversion potential in the city’s center and outer suburbs, but higher land conversion potential in the inner near suburbs along the belt expressway. Residual statistics show that GWR fits the input data better than logistic regression (LR). Compared with an LR-based CA model, GWR-CA improves overall accuracy by 4.1% and captures 5.5% more urban growth, suggesting that GWR-CA may be superior in modeling land use change. Our results demonstrate that the GWR-CA model is effective in capturing spatially varying land transition rules to produce more realistic results, and is suitable for simulating land use change and urban expansion in rapidly urbanizing regions.     

基于弱光栅技术的地面沉降自动化监测系统

光纤监测技术具有分布式、精度高等特点,在地面沉降监测中具有独特优势。但受限于监测成本较高与监测环境复杂,目前地面沉降光纤监测多通过人工采集数据,限制了在特殊环境变化情况下地面沉降的实时信息获取。文章在地面沉降钻孔全断面光纤监测技术的基础上,设计并建立了基于弱光栅技术的地面沉降自动化监测系统。该监测系统利用弱反射光栅、时分复用、物联网和数据库等技术,通过4G无线通信手段实现了地面沉降在线自动化监测和远程数据实时采集,并通过客户端系统软件实现数据的存储、查询和分析。将其应用到衡水地区地面沉降监测中,结果表明:钻孔内土层压缩变形主要发生在以黏性土为主的隔水层（Ad2、Ad3、Ad4）;受季节性地下水开采的影响,钻孔100～400 m深度范围内砂土含水层存在波动变化,在监测期内,冬季略回弹,随后春季地下水开采量增大,地下水位下降,土层呈现压缩趋势。监测结果验证了该系统的可行性与准确性,使得整个地面沉降监测流程趋于自动化、规范化和低成本化,具有广泛的应用前景。