In the last two to three decades or so, the spatial pattern of mineral occurrences of a deposit-type has been studied to derive insights to mineralization controls and assist mineral exploration. In the Skellefte district, Fry plots of volcanogenic massive sulfide (VMS) mines/prospects reveal patterns that are likely due to post-mineralization deformation events. The fractal dimensions of the spatial patterns of the present-day VMS mines/prospects and that of the ‘original’ VMS deposits support the concept that spatial patterns of mineral deposits are spatially-invariant. Therefore, analysis of the spatial pattern of mineral deposits is useful not only in research about pre- and syn-mineralization geological settings but also post-mineralization geological settings.
Emergy theory and method are used to evaluate the contribution of irrigation water, and the process of its utilization, in three agricultural systems. The agricultural systems evaluated in this study were rice, wheat, and oilseed rape productions in an irrigation pumping district of China. A corresponding framework for emergy evaluation and sensitivity analysis methods was proposed. Two new indices, the fraction of irrigation water (FIW), and the irrigation intensity of agriculture (IIA), were developed to depict the contribution of irrigation water. The calculated FIW indicated that irrigation water used for the rice production system (34.7%) contributed more than irrigation water used for wheat (5.3%) and oilseed rape (11.2%) production systems in a typical dry year. The wheat production with an IIA of 19.0 had the highest net benefit from irrigation compared to the rice (2.9) and oilseed rape (8.9) productions. The transformities of the systems’ products represented different energy efficiencies for rice (2.50E+05 sej·J-1), wheat (1.66E+05 sej·J-1) and oilseed rape (2.14E+05 sej·J-1) production systems. According to several emergy indices, of the three systems evaluated, the rice system had the greatest level of sustainability. However, all of them were less sustainable than the ecological agricultural systems. A sensitivity analysis showed that the emergy inputs of irrigation water and nitrogenous fertilizer were the highest sensitivity factors influencing the emergy ratios. Best Management Practices, and other agroecological strategies, could be implemented to make further improvements in the sustainability of the three systems.
Activities related to agricultural cultivation are some of the major human drivers of landscape change on the Earth’s surface. Archaeological remains can provide qualitative evidence for studies of past agricultural development and environmental conditions. The ancient Juyan Oasis, which once flourished along the historic Silk Road, was a typical oasis of downstream inland river basins in the arid zone of northwestern China. Historical records and archaeological discoveries have qualitatively shown that the oasis supported extensive agricultural activities in this historical period from the Han Dynasty to the early Ming Dynasty (B.C. 202–A.D. 1375), which can be traced back to 2,000 years ago. In this study, different types of archaeological remains (including archaeological sites, ground surface artifacts, ancient cultivation ruins, and agricultural irrigation canals) that were obtained and identified from previous archaeological reports, field inspections, and remote sensing imagery were used to determine the spatial extent of the agricultural oasis in the historical period of interest. Our approach used multiple data sources in order to increase the accuracy and reliability of the results compared to previous studies. Our results distinctly suggested that much of the oasis was cultivated during the historical periods considered. Additionally, the arable land area in the historical period considered was roughly estimated to be approximately (3.39–4.75) × 104 ha. These findings regarding the spatial distribution of this ancient agricultural oasis and its arable land were reasonably determined to represent the ancient agricultural development that occurred in the Juyan Oasis better than results obtained from single sources of data.
Aquatic ecosystems of highland rivers are different from those of low altitude rivers because of the specific topography and environmental parameters associated with high altitudes. Yalutsangpo, the upper course of the Brahmaputra River, is the highest major river in the world, flowing from west to east across Tibet, China and pouring into India. Macroinvertebrates were sampled from Yalutsangpo and its tributaries, the Lhasa, Niyang, and Parlong Tsangpo Rivers, from October 2009 to June 2010, to study characters of the highland aquatic ecosystem. Altogether, 110 macroinvertebrate taxa belonging to 57 families and 102 genera were identified from the basin. The biodiversity and composition of macroinvertebrate assemblages were strongly affected by altitude gradients. Local diversity represented by taxa richness and the improved Shannon-Wiener index were high at altitudes of 3,300–3,700 m, among which suitability of habitat was higher due to the better integrated environmental conditions of water temperature, dissolved oxygen, and aquatic vegetation, etc. Macroinvertebrates were grouped into shredders, scrapers, predators, collector-filterers, and collector-gatherers according to their feeding behaviors. It was found that the distributions of the functional feeding groups varied with habitat altitudes. Shredders were present at altitudes of 2,900–4,400 m, while scrapers mainly inhabited altitudes of 3,500–4,500 m, and collector-?lterers preferred 3,500–4,000 m.
Even though the local taxa richness was not high at each site, the taxonomic composition and density of the assemblages varied greatly among the different sites, resulting in much higher regional diversity compared to the lowland river with similar flow and substrate conditions. The regional cumulative taxa richness of Yalutsangpo decreased and more families were lost as the altitude increased. However, some families that were newly present as the attitude increased were essential for sustaining the high regional biodiversity. The ordination diagram obtained from Detrended Correspondence Analysis indicated that altitude, river pattern, riverbed structures, bank structures, and flow conditions were the main factors that influenced the macroinvertebrate assemblages in the Yalutsangpo basin.
With the rising pressure due to energy consumption and costs of environmental protection and recovery, industrial transfer from the eastern to central and western areas has surged in China. However, extremely fragile ecological conditions and severe water shortage are significant hurdles for industry development in Western China. Whether the vulnerable environment can bear the pollution caused by the transferred industry from Eastern China becomes a significant issue. This study firstly estimates energy and environmental costs in different areas of China, and assesses the necessity to upgrade the industrial structure of Qinghai Province. Then the emissions of waste water, waste gas, and smoke caused by transferred industries are calculated by Input-Output Model. On the basis of the effect analysis of waste emission on environment, pollution risks of Qinghai province are assessed. The results illustrate that the costs of environmental protection and recovery in China have a gradient distribution, of which the energy efficiency is lower while environmental costs are higher in Western China. Industrial structure adjustment has different impacts on the pollution of different sectors. Although the development of machinery and equipment, hotels and catering services, and real estate, leasing, and business services has increased the emission of pollutants, it is offset by the decreasing emissions caused by other industries such as construction and metal products. Therefore, although economic development will increase environmental pollution, industrial adjustments can effectively decrease waste water and waste gas emissions to reduce the pollution risk. It should be noted that there are still tremendous challenges for industrial transfer in Qinghai Province to coordinate the environment and industry development.
The aim of this work was to present the common anaerobic digestion technologies in a typical farm-scale biogas plant in China. The comprehensive benefits of most biogas plants in China have not been fully assessed in past decades due to the limited information of the anaerobic digestion processes in biogas plants. This paper analyzed four key aspects (i.e., operational performance, nonrenewable energy (NE) savings, CO2 emission reduction (CER) and economic benefits (EBs)) of a typical farm-scale biogas plant, where beef cattle manure was used as feedstock. Owing to the monitoring system, stable operation was achieved with a hydraulic retention time of 18–22 days and a production of 876,000 m3 of biogas and 37,960 t of digestate fertilizer annually. This could substantially substitute for the nonrenewable energy and chemical fertilizer. The total amount of NE savings and CER derived from biogas and digestate fertilizer was 2.10×107 MJ (equivalent to 749.7 tce) and 9.71×105 kg, respectively. The EBs of the biogas plant was 6.84×105 CNY·yr−1 with an outputs-to-inputs ratio of 2.37. As a result, the monitoring system was proved to contribute significantly to the sound management and quantitative assessment of the biogas plant. Biogas plants could produce biogas which could be used to substitute fossil fuels and reduce the emissions of greenhouse gases, and digestate fertilizer is also an important bio-product.
Sea ice in polar areas is an important part of the global climate system. In order to obtain variations in sea ice extent for the Antarctic and Arctic, this paper analyzed the Special Sensor Microwave/Imager (SSM/I) sea ice data product dating from March 1, 1997 to December 31, 2006. During this period, the sea ice extent increased in the Antarctic with the trend of (0.5467±0.4933)×104 km2·yr–1, and decreased in the Arctic with the trend of (–7.6125±0.3503)×104 km2·yr–1. In different sectors of the Antarctic, variations of the sea ice extent are different. The sea ice extent increased in the Weddell Sea and Indian Ocean, but decreased in the Ross Sea, Western Pacific Ocean, and Bellingshausen/Amundsen Seas.
Global land use structure is changing rapidly due to unceasing population growth and accelerated urbanization, which leads to fierce competition between the rigid demand for built-up area and the protection of cultivated land, forest, and grassland. It has been a great challenge to realize the sustainable development of land resources. Based on a computable general equilibrium model of land use change with a social accounting matrix dataset, this study implemented an equilibrium analysis of the land use structure in the Yunnan Province during the period of 2008–2020 under three scenarios, the baseline scenario, low TFP (total factor productivity) scenario, and high TFP scenario. The results indicated that under all three scenarios, area of cultivated land declined significantly along with a remarkable expansion of built-up area, while areas of forest, grassland, and unused land increased slightly. The growth rate of TFP had first negative and then positive effects on the expansion of built-up area and decline of cultivated land as it increased. Moreover, the simulated changes of both cultivated land and built-up area were the biggest under the low TFP scenario, and far exceeded the limit in the Overall Plan for Land Utilization in the Yunnan Province in 2020. The scenario-based simulation results are of important reference value for policy-makers in making land use decisions, balancing the fierce competition between the protection of cultivated land and the increasing demand for built-up area, and guaranteeing food security, ecological security, and the sustainable development of land resources.
Sensitivity analyses were conducted for the retrieval of vegetation leaf area index (LAI) from multi-angular imageries in this study. Five spectral vegetation indices (VIs) were derived from Compact High Resolution Imaging Spectrometer onboard the Project for On Board Autonomy (CHRIS/PROBA) images, and were related to LAI, acquired from in situ measurement in Jiangxi Province, China, for five vegetation communities. The sensitivity of LAI retrieval to the variation of VIs from different observation angles was evaluated using the ratio of the slope of the best-fit linear VI-LAI model to its root mean squared error. Results show that both the sensitivity and reliability of VI-LAI models are influenced by the heterogeneity of vegetation communities, and that performance of vegetation indices in LAI estimation varies along observation angles. The VI-LAI models are more reliable for tall trees than for low growing shrub-grasses and also for forests with broad leaf trees than for coniferous forest. The greater the tree height and leaf size, the higher the sensitivity. Forests with broad-leaf trees have higher sensitivities, especially at oblique angles, while relatively simple-structured coniferous forests, shrubs, and grasses show similar sensitivities at all angles. The multi-angular soil and/or atmospheric parameter adjustments will hopefully improve the performance of VIs in LAI estimation, which will require further investigation.
Using the most detailed and recent statistics available for Beijing, a local-scale embodiment analysis on water use was conducted, employing a systems input-output analysis that integrates economic systems with natural resources data. Systems analysis for water research at the local scale is a crucial part of a systems oriented water accounting framework. To our knowledge, however, related works have not been thoroughly conducted. In this paper, a set of embodied water intensity inventory data is presented, which is applicable to both intermediate input and final demand. Also, detailed analyses of Beijing’s embodied water use accounting are presented. The embodied water intensity of the Water Production and Supply Industry Sector turns out to be the highest among the 42 sectors. For water embodied in final demand, the total amount is 3.48 km3, of which the water embodied in urban household consumption makes up nearly a half proportion. As a net virtual water importer, Beijing’s water embodied in commodity trade totals 5.84×108 m3. As a result, in addition to improvements in technology and water use efficiency, adjustments in industrial structure and trade policies are also of significant importance to water conservation efforts.
A simplified physically-based algorithm for surface soil moisture inversion from satellite microwave radiometer data is presented. The algorithm is based on a radiative transfer model, and the assumption that the optical depth of the vegetation is polarization independent. The algorithm combines the effects of vegetation and roughness into a single parameter. Then the microwave polarization difference index (MPDI) is used to eliminate the effects of surface temperature, and to obtain soil moisture, through a nonlinear iterative procedure. To verify the present algorithm, the 6.9 GHz dual-polarized brightness temperature data from the Advanced Microwave Scanning Radiometer (AMSR-E) were used. Then the soil moisture values retrieved by the present algorithm were validated by in-situ data from 20 sites in the Tibetan Plateau, and compared with both the NASA AMSR-E soil moisture products, and Soil Moisture and Ocean Salinity (SMOS) soil moisture products. The results show that the soil moisture retrieved by the present algorithm agrees better with ground measurements than the two satellite products. The advantage of the algorithm is that it doesn’t require field observations of soil moisture, surface roughness, or canopy biophysical data as calibration parameters, and needs only single-frequency brightness temperature observations during the whole retrieval process.
The shear strength parameters of soil (cohesion and angle of internal friction) are quite essential in solving many civil engineering problems. In order to determine these parameters, laboratory tests are used. The main objective of this work is to evaluate the potential of Artificial Neural Network (ANN) and Regression Tree (CART) techniques for the indirect estimation of these parameters. Four different models, considering different combinations of 6 inputs, such as gravel %, sand %, silt %, clay %, dry density, and plasticity index, were investigated to evaluate the degree of their effects on the prediction of shear parameters. A performance evaluation was carried out using Correlation Coefficient and Root Mean Squared Error measures. It was observed that for the prediction of friction angle, the performance of both the techniques is about the same. However, for the prediction of cohesion, the ANN technique performs better than the CART technique. It was further observed that the model considering all of the 6 input soil parameters is the most appropriate model for the prediction of shear parameters. Also, connection weight and bias analyses of the best neural network (i.e., 6/2/2) were attempted using Connection Weight, Garson, and proposed Weight-bias approaches to characterize the influence of input variables on shear strength parameters. It was observed that the Connection Weight Approach provides the best overall methodology for accurately quantifying variable importance, and should be favored over the other approaches examined in this study.