Tracing water resources flows by complementary use of hydrological and water accounting models

Historically, there has been a dispute over water allocation between users and policymakers in Iran's Zayandeh-Roud Basin (ZRB). In this study, we used the “System of Environmental-Economic Accounting for Water” (SEEAW) framework in combination with the hydrologic model “Soil and Water Assessment Tool” (SWAT) to achieve the water balance in ZRB. We used SEEAW to combine a wide range of water-related statistics across stakeholders and SWAT to evaluate the unknown agricultural water use. The SWAT model is calibrated based on the stream flows and crop yields in the basin. The model assess the renewable water of the basin into two components, about 363 and 70 mm as green and blue water, respectively. Also results from the physical water supply and water use tables demonstrates that the agricultural sector uses 78% of the total renewable freshwater, followed by the residential, 16%, and the industrial sector, 6%. The flows of water from source to services in ZRB are traced based on the water supply and water use tables. The flow diagram shows that 8 MCM of industrial reused water was transferred to the agricultural sector, and 137 MCM and 18 MCM of water from the wastewater treatment plants to the agricultural and industrial sectors, respectively. Furthermore, the results show that the index of the basin dependence on groundwater resources is high (61%), the value of water stress is high (0.88) and the dependence of the basin on transboundary water resources is 30%. Therefore, this method is highly beneficial for achieving a conceptual water balance in disputed basins without enough agricultural water uses data.     

利用射电天线轴线信息测定VLBI站点垂线偏差

本文采用直接法推导了射电天线轴系误差的指向改正模型的完全表达式,统一了轴系误差指向改正模型与L?sler归心测量模型中共有轴系参数的定义,建立了射电天线指向测量模型与归心测量模型中天线方位轴倾角参数间的联系,从而实现了利用射电天线方位轴信息测定VLBI测站垂线偏差(DOV)的方法.该方法不依赖专用DOV测量设备,仅需天...     

Innovative mitigation method for buried pipelines crossing faults

A new remediation technique is proposed to mitigate large deformations imposed on buried pipeline systems subject to permanent ground deformation. With this technique, low-density gravel(LDG) with high porosity, such as pumice,is used as backfill in the trench containing the pipe near an area susceptible to PGD. This countermeasure decreases soil resistance, soil-pipe interaction forces and strain on the pipe as the pipeline deformation mechanism changes to a more desirable shape. Expanded polys...     

Integration of maximum crop response with machine learning regression model to timely estimate crop yield

Timely and reliable estimation of regional crop yield is a vital component of food security assessment, especially in developing regions. The traditional crop forecasting methods need ample time and labor to collect and process field data to release official yield reports. Satellite remote sensing data is considered a cost-effective and accurate way of predicting crop yield at pixel-level. In this study, maximum Enhanced Vegetation Index (EVI) during the crop-growing season was integrated with Machine Learning Regression (MLR) models to estimate wheat and rice yields in Pakistan's Punjab province. Five MLR models were compared using a fivefold cross-validation method for their predictive accuracy. The study results revealed that the regression model based on the Gaussian process outperformed over other models. The best performing model attained coefficient of determination (R2), Root Mean Square Error (RMSE, t/ ha), and Mean Absolute Error (MAE, t/ha) of 0.75, 0.281, and 0.236 for wheat; 0.68, 0.112, and 0.091 for rice, respectively. The proposed method made it feasible to predict wheat and rice 6– 8 weeks before the harvest. The early prediction of crop yield and its spatial distribution in the region can help formulate efficient agricultural policies for sustainable social, environmental, and economic progress.     

Changes in the frequency of tropical cyclones over the North Indian Ocean

Summary  Changes in the frequency of tropical cyclones developing over the Arabian Sea and the Bay of Bengal have been studied utilizing 122 year (1877–1998) data of tropical cyclone frequency. There have been significant increasing trends in the cyclone frequency over the Bay of Bengal during November and May which are main cyclone months. During transitional monsoon months; June and September however, the frequency has decreased. The results have been presented for five months, i.e., May-November which are relevant as far as tropical cyclone frequency over the Arabian Sea and the Bay of Bengal are concerned. The tropical cyclone frequency in the Arabian Sea has not shown any significant trend, probably due to small normal frequency. The frequency time series has been subjected to the spectral analysis to obtain the significant periods. The cyclone frequency over the Bay of Bengal during May has shown a 29 year cycle. A significant 44 year cycle has been found during November. Over the Arabian Sea significant cycles of 13 and 10 years have been observed during May-June and November, respectively. The tropical cyclone frequency in the North Indian Ocean has a prominent El Ni?o-Southern Oscillation (ENSO) scale cycle (2–5 years) during all above five months. The annual cyclone frequency exhibits 29 year and ENSO scale (2–4 years) oscillations. There is a reduction in tropical cyclone activity over the Bay of Bengal in severe cyclone months May and November during warm phases of ENSO. Examination of the frequencies of severe cyclones with maximum sustained winds ≥ 48 knots has revealed that these cyclones have become more frequent in the North Indian Ocean during intense cyclone period of the year. The rate of intensification of tropical disturbances to severe cyclone stage has registered an upward trend. Received June 7, 1999/Revised March 20, 2000     

Modelling Regional Climate Change Effects On Potential Natural Ecosystems in Sweden

This study aims to demonstrate the potential of a process-based regional ecosystem model, LPJ-GUESS, driven by climate scenarios generated by a regional climate model system (RCM) to generate predictions useful for assessing effects of climatic and CO₂ change on the key ecosystem services of carbon uptake and storage. Scenarios compatible with the A2 and B2 greenhouse gas emission scenarios of the Special Report on Emission Scenarios (SRES) and with boundary conditions from two general circulation models (GCMs) – HadAM3H and ECHAM4/OPYC3 – were used in simulations to explore changes in tree species distributions, vegetation structure, productivity and ecosystem carbon stocks for the late 21st Century, thus accommodating a proportion of the GCM-based and emissions-based uncertainty in future climate development. The simulations represented in this study were of the potential natural vegetation ignoring direct anthropogenic effects. Results suggest that shifts in climatic zones may lead to changes in species distribution and community composition among seven major tree species of natural Swedish forests. All four climate scenarios were associated with an extension of the boreal forest treeline with respect to altitude and latitude. In the boreal and boreo-nemoral zones, the dominance of Norway spruce and to a lesser extent Scots pine was reduced in favour of deciduous broadleaved tree species. The model also predicted substantial increases in vegetation net primary productivity (NPP), especially in central Sweden. Expansion of forest cover and increased local biomass enhanced the net carbon sink over central and northern Sweden, despite increased carbon release through decomposition processes in the soil. In southern Sweden, reduced growing season soil moisture levels counterbalanced the positive effects of a longer growing season and increased carbon supply on NPP, with the result that many areas were converted from a sink to a source of carbon by the late 21st century. The economy-oriented A2 emission scenario would lead to higher NPP and stronger carbon sinks according to the simulations than the environment-oriented B2 scenario.     

A Field Experiment on Dust Emission by Wind Erosion in the Taklimakan Desert

Dust emission by wind erosion in surface is a serious problem in many arid regions around the world,and it is harmful to the ecological environment,human health,and social economy.To monitor the characteristics of saltation activity and to calculate the threshold wind velocity and sediment discharge under field conditions have significance on the research of dust emission by wind erosion.Therefore,a field experiment was conducted over the flat sand in the hinterland of the Taklimakan Desert.One sampling system was installed on the flat sand surface at Tazhong,consisting of a meteorological tower with a height of 2 m,a piezoelectric saltation sensor(Sensit),and a Big Spring Number Eight(BSNE) sampler station.Occurrence of saltation activity was recorded every second using the Sensit.Each BSNE station consisted of five BSNE samplers with the lowest sampler at 0.05 m and the highest sampler at 1.0 m above the soil surface.Sediment was collected from the samplers every 24 h.It is found that saltation activity was detected for only 21.5% of the hours measured,and the longest period of saltation activity occurring continuously was not longer than 5 min under the field conditions.The threshold wind velocity was variable,its minimum value was 4.9 m s 1,the maximum value was 9.2 m s 1,and the average value was 7.0 m s 1.The threshold wind velocity presented a positive linear increase during the measurement period.The observation site had a sediment discharge of 82.1 kg m 1 over a period of 24 h.Based on hourly saltation counts,hourly sediment discharge was estimated.Overall,there was no obvious linear or other functional relationship between the hourly sediment discharge and wind velocity.The results show that the changes of sediment discharge do not quite depend on wind velocity.     

模糊证据权方法在镇沅(老王寨)地区金矿资源评价中的应用

采用模糊证据权方法和GeoDASGIS技术开展了镇沅(老王寨)及其邻区的金矿资源潜力评价.分别采用GeoDASGIS软件提供的局部奇异性分析技术、S-A异常分解技术、主成分分析技术、证据权、模糊证据权等技术对相关地球化学元素进行了系统的处理和分析.应用主成分分析方法确定了可能的2种不同成矿类型,并采用主成分得分确定了组合异常点,在此基础上分别采用普通证据权和模糊证据权方法编制了成矿后验概率图,圈定了有利成矿地段.对比普通证据权方法与模糊证据权方法所得结果表明,模糊证据权方法可减小图层离散化造成的有用信息损失,提高预测结果精度.     

Petrography,geochemistry, and provenance of the Chalki rocks in Kurdistan region,North Iraq

Outcrops of the Paleozoic Chalki volcanic rocks are restricted to part of the northern Thrust Zone of Iraq close to Iraqi-Turkish border. Petrographically, the volcanic rocks from the Chalki area are mainly layered, appearing fresh in the field and exhibiting some basaltic lava flows. Porphyritic, amygdaloidal, and microlite-porphyric are the main observed textures. Phenocrysts of primary phases (i.e., olivine, iron oxides) are in a groundmass of feldspars and clinopyroxene. Chalki Formation is intercalated with Pirispiki Formation which consists of thin to medium bedded, greenish gray marl, red mudstone, and veins of calcite. The Chalki rocks are mafic of theolitic basalt type. Geochemically, they have high chromium and nickel concentrations in most samples. Rare earth element (REE) patterns illustrate parallel to sub-parallel, moderately fractionated REE patterns. The low heavy REE (HREE) contents in the studied samples appear to be due to partial melting of metamorphosed oceanic crust leaving HREE-rich accessory minerals (i.e., garnet) as a residual phase in the source. No Eu anomalies were observed in the Chalki samples which may indicate a back-arc basin pattern. The non-subduction signature of the Chalki rocks is confirmed by the Nb/Yb versus Th/Yb diagram, which shows that most of the studied rocks fall in the compositional field of non-arc-related rocks—well within the field of the mid-ocean ridge basalt (MORB)-ocean island basalt (OIB) mantle array.