孟加拉国农业利用强度增加、土地利用/覆盖变化和土地退化

在实地采访、地块土地利用/覆盖调查和1 260个土样的收集和实验室分析等野外工作的基础上,对比分析了1984—1985年和2003—2004年265个家户的人口、农业系统、土地利用和土壤质量数据,研究了孟加拉国6个村庄农业诱导强度增强对土地和土壤质量的影响。1984—2004年家户和土质数据的百分比变化用来构建诱导强度增强模型和土地退化模型中的统计变量和土地退化指标。结果表明：研究区种植强度和土地生产力的增加主要是由于低压泵灌溉的普及,化肥和杀虫剂的使用以及水稻、蔬菜和虾生产的多元化高产。诱导强度增强模型可以解释研究区81%的种植强度增量和73%的土地生产力增量。人口压力和市场驱动也诱发了农业利用强度的增加;环境约束起到了一定制约作用;低压泵灌溉等应对干旱的技术也对农业增产有一定贡献。然而动力耕作机、低压泵灌溉和化学物质的持续利用再加上除草性水稻、蔬菜和虾的频繁耕作和养殖已经导致土壤结构、质地和化学属性的退化,生产力也有所降低。利用强度越大的土地退化现象越严重,生产力下降得也更多。土地的不断退化将有可能会引发孟加拉国的马尔萨斯危机。     

地热储层单裂隙岩体渗流传热数值模拟研究

研究地热储层裂隙岩体中的渗流传热过程对干热岩地热资源的开采具有重要的意义。本文以干热岩地热工程为背景,采用COMSOL Multiphysics数值模拟软件对地热储层单裂隙岩体中渗流传热机理进行了研究,并分析了流体注入速度和温度对岩体温度场的影响及其对干热岩地热工程的影响。研究发现流体参数对岩体温度场的影响主要体现在两个方面：一方面是对岩体温度场受扰动区域以及幅度的影响,另一方面是对岩体温度场达到稳态所需要时间的影响。流体注入速度的提升会降低系统的寿命和寿命期的出口法向总热量值,当考虑出口法向总热通量时,存在最佳流体注入速度,本研究中最佳流体注入速度为0.011m/s。流体注入温度的提升会增加系统的寿命和系统的出口法向总热通量和总热量。研究为干热岩自热资源的开发与利用提供了理论依据,为工程运行参数的设计提供了参考依据。     

Extracting the damaging effects of the 2010 eruption of Merapi volcano in Central Java, Indonesia

This research focuses on providing information related to the damaging effects of the 2010 eruption of Merapi volcano in Central Java, Indonesia. This information will be used to help emergency responders to assess losses more timely and efficiently, and to monitor the progress in emergency response and recovery. The objectives of this research are: (a) to generate a map of pyroclastic deposits based on activities pre- and post-volcano eruption of 2010 in the research area, (b) to investigate the impact of volcano eruption on the environment, and (c) to assess the impact of volcano eruption on landuse. ALOS PALSAR remote sensing data pre- and post-disaster were used in this research for mapping the volcano eruption. Topographic and geomorphological maps were analyzed for profiling and field orientation, which were used to investigate the impact of volcano eruption on the environment. SPOT 4 satellite images were used in this research for updating landuse information from the topographic map. The result of the landuse updated data was used for assessment of the volcano eruption’s impact on landuse with the GIS raster environment. The volcanic eruption that occurred in 2010 is estimated to have an impact of 133.31 ha for settlements, 92.32 ha for paddy fields, 235.60 ha for dry farming, 570.98 ha for plantations, 380.86 ha for bare land, and 0.12 ha for forest areas. An estimate of the number of buildings damaged due to the volcano eruption in 2010 was carried out by overlaying a map of pyroclastic deposits and the information point of the building sites from the topographic map. The total number of buildings damaged is estimated to be around 12,276 units.     

Detrital zircon U–Pb geochronology of a Cenozoic foreland basin in Northeast India: Implications for zircon provenance during the collision of the Indian and Asian plates

Geochronology is useful for understanding provenance, and while it has been applied to the central and western Himalaya, very little data are available in the eastern Himalaya. This study presents detrital zircon U–Pb ages from the late Palaeocene–Eocene Yinkiong Group in NE India. The samples are from the late Palaeocene to early Eocene Lower Yinkiong Formation, and the Upper Yinkiong Formation deposited during the early to mid‐Eocene within the Himalayan foreland basin. The U–Pb ages of the detrital zircon within the Lower Yinkiong Formation are older than late Palaeozoic, with a cratonic and early Himalayan Thrust Belt affinity, whereas the Cenozoic grains in the Upper Yinkiong Formation indicate a Himalayan Thrust Belt source and possibly a granitic body within the Asian plate. The shift of the sources and the changes in the foreland basin system strongly suggest that the India–Asia collision in the Eastern Himalaya began before or immediately after the deposition of the Upper Yinkiong Formation, i.e., within the early Eocene (c. 56 to 50 Ma).     

Climatology of dust storm frequency and its association with temperature and precipitation patterns over Pakistan

Natural Hazards - Diversified topography and uneven distribution of both temperature and precipitation contribute to formation of suitable synoptic conditions for incidents of dust storm (DS). This...     

The evolution of an electrical fittings industrial cluster in Pakistan

GeoJournal - This study provides an evolution process of electrical fittings industrial cluster in Pakistan by using two rounds of survey dataset (2008 and 2017) taken from the electrical fittings...     

Spatio-Temporal Assessment of Groundwater Potential Zone in the Drought-Prone Area of Bangladesh Using GIS-Based Bivariate Models

Natural Resources Research - Groundwater is one of the most dynamic and renewable natural resources found in the earth’s crust. A spatio-temporal assessment of groundwater potential zone...     

Bartonian orthophragminids from the Fulra Limestone (Kutch,W India) and coeval units in Sulaiman Range,Pakistan: a synthesis of shallow benthic zone (SBZ) 17 for the Indian Subcontinent

Orthophragminids from the Bartonian Fulra Limestone in Kutch, India and the coeval units in Sulaiman Range in Pakistan suggest the establishment of a significant number of endemic species in the Indian subcontinent (Eastern Tethys). Among a total of fifteen species of Discocyclina, Orbitoclypeus and Asterocyclina, six of them appear to be confined to Indian subcontinent while seven species are common both to the peri-Mediterranean/Europe region (Western Tethys) and Indian subcontinent. Two species, Asterocyclina sireli, a four-ribbed species of possibly Indo-Pacific origin, and Orbitoclypeus haynesi that form large populations in Fulra Limestone, appear to have spread into North Africa and Turkey but not into European platforms as a response to Middle Eocene Climatic Optimum (MECO). The lack of Lutetian and Priabonian fauna in the studied sections, either due to a hiatus or unsuitable depositional environments, hampers the establishment of the actual stratigraphic ranges of the identified taxa. Our record provides us to characterize the orthophragminids in shallow benthic zone (SBZ) 17 for Eastern Tethys in detail by comparing the data from the above localities with those from the North Africa, Europe and Turkey, showing the change in diversity.     

Satellite-based rainfall estimation and discharge measurement of Middle Indus River,Pakistan

The impacts of floods and droughts are intensified by climate change, lack of preparedness, and coordination. The average rainfall in study area is ranging from 200 to 400 mm per year. Rain gauge generally provides very accurate measurement of point rain rates and the amounts of rainfall but due to scarcity of the gauge locations provides very general information of the area on regional scale. Recognizing these practical limitations, it is essential to use remote sensing techniques for measuring the quantity of rainfall in the Middle Indus. In this research, Tropical Rainfall Measuring Mission (TRMM) estimation can be used as a proxy for the magnitude of rainfall estimates from classical methods (rain gauge), quantity, and its spatial distribution for Middle Indus river basin. In order to use TRMM satellite data for discharge measurement, its accuracy is determined by statistically comparing it with in situ gauged data on daily and monthly bases. The daily R ² value (0.42) is significantly lower than monthly R ² value (0.82), probably due to the time of summation of TRMM 3-hourly precipitation data into daily estimates. Daily TRMM data from 2003 to 2012 was used as input forcing in Soil and Water Assessment Tool (SWAT) hydrological model along with other input parameters. The calibration and validation results of SWAT model give R ² = 0.72 and 0.73 and Nash-Sutcliffe coefficient of efficiency = 0.69 and 0.65, respectively. Daily and monthly comparison graphs are generated on the basis of model discharge output and observed data.     

Prediction of pore-water pressure response to rainfall using support vector regression

Nonlinear complex behavior of pore-water pressure responses to rainfall was modelled using support vector regression (SVR). Pore-water pressure can rise to disturbing levels that may result in slope failure during or after rainfall. Traditionally, monitoring slope pore-water pressure responses to rainfall is tedious and expensive, in that the slope must be instrumented with necessary monitors. Data on rainfall and corresponding responses of pore-water pressure were collected from such a monitoring program at a slope site in Malaysia and used to develop SVR models to predict pore-water pressure fluctuations. Three models, based on their different input configurations, were developed. SVR optimum meta-parameters were obtained using k-fold cross validation and a grid search. Model type 3 was adjudged the best among the models and was used to predict three other points on the slope. For each point, lag intervals of 30 min, 1 h and 2 h were used to make the predictions. The SVR model predictions were compared with predictions made by an artificial neural network model; overall, the SVR model showed slightly better results. Uncertainty quantification analysis was also performed for further model assessment. The uncertainty components were found to be low and tolerable, with d-factor of 0.14 and 74 % of observed data falling within the 95 % confidence bound. The study demonstrated that the SVR model is effective in providing an accurate and quick means of obtaining pore-water pressure response, which may be vital in systems where response information is urgently needed.