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181.
Climatic data from four meteorological stations in Iraq (Mosul, Baghdad, Basra, and Rutba) were obtained. The recorded temperature data since 1960 till 2007 and rainfall and evaporation data since 1960 till 2008 and 1970 till 2008, respectively, were used and interpreted. This study showed an increase in temperature of about 5°C/47?years and an increase in evaporation rate with a decrease in the rainfall rate. Carbon dioxide in the atmosphere appears to be a factor controlling climate change. Basra climate, due to its location which is nearest to the Arabian Gulf, is expressed as a coastal climate and has a different behavior from Mosul, Baghdad, and Rutba, which are considered as terrestrial climates. 相似文献
182.
Imran A. Dar K. Sankar Tanzeem S. Shah Mithas A. Dar 《Arabian Journal of Geosciences》2012,5(2):233-243
Nitrate contamination in the groundwater from various sources is one of the major problems of water resources in Liddercatchment, Kashmir. Systematic sampling was carried out during summer 2007, with a view to understand the source of nitrate ions in the groundwater of the Lidder catchment. Twelve sample sites were selected and samples were taken for a baseline study to understand the geochemistry of the groundwater and to assess the overall physico-chemical characteristics. Results showed that NO 3 ? concentration in ranged from 18.72?mg/L to 75.93?mg/L with an average of 47.03?mg/L. More than 80% (83.33%) of the samples collected from various sampling stations had nitrate concentrations exceeding the threshold value of 20?mg/L, and 58.33% of the samples collected had nitrate concentrations higher than 50?mg/L, the maximum acceptable nitrate concentration for drinking water. There is a wide spatial variation in the nitrate concentration in the groundwater. Monitoring the water quality of various sampling stations showed that the lowest concentrations of nitrate were found in the wet season (January, February, and December), while the highest concentrations were found in the dry season (August, September). Numerous human perturbations have been detected affecting the water quality of Lidder catchment. Disposal of sewage and animal wastes was found to contribute about 85% of total nitrate pollution in the study area. Based on the trend analysis (using previous data), future scenario of nitrate pollution has been predicted in the study area. The results of this study are useful to highlight one of the most important environmental problems, namely the degradation of the water quality, and may serve to alert and encourage local and national authorities to take substantial steps and actions to protect and manage water quality. 相似文献
183.
Annual and seasonal trends of cooling, heating, and industrial degree-days in coastal regions of Saudi Arabia 总被引:1,自引:0,他引:1
Shafiqur Rehman Luai M. Al-Hadhrami Shamsuddin Khan 《Theoretical and Applied Climatology》2011,103(3-4):479-488
In this study, we systematically analyze the changing properties of reference evapotranspiration (ETref) across China using Penman?CMonteith (P-M) method, exploring the major sensitive meteorological variables for ETref, and investigating influences of human activities, mainly urbanization in this study, on ETref changes in both space and time. We obtain some important conclusions: (1) decreasing annual and seasonal ETref is observed in the east, south and northwest China. However, a long strip lying between these regions is identified to be characterized by increasing ETref; (2) in the regions east to 100°E, the net total solar radiation is the main cause behind the decreasing ETref. In northwest China, however, relative humidity is recognized as the most sensitive variable for the ETref; (3) in the east and south China, urbanization greatly influences the ETref by directly decreasing net solar radiation. The increased air pollution and aerosols in the highly urbanized regions are the main driving factors causing decreasing net radiation; and (4) this study reveals accelerating hydrological cycle from south to north China. Besides, increasing ETref in the source regions of large rivers in China may pose new challenges for the basin-scale water resource management. The results of this study highlight the integrated effects of climate changes and human activities on ETref changes in different regions of China, which will be of great scientific and practical merits in in-depth understanding of hydrological cycle alterations under the changing environment in China. 相似文献
184.
The activities of 210Po and 210Pb were determined in commonly consumed seafoods to evaluate the internal exposure and risk to humans residing Kudankulam coast where a mega nuclear power plant is under construction. The concentration of 210Po in seafoods ranged from 1.2 ± 0.7 to 248 ± 8.1 Bq kg−1. Meanwhile, 210Pb ranged between 1.1 ± 0.05 and 14.8 ± 1.6 Bq kg−1. The committed effective dose (CED) due to 210Po and 210Pb varied from 11.04 to 515.6 and 3.93 to 23.5 μSv yr−1, respectively. The lifetime cancer risk for the public due to 210Po was in the range of 3.47 × 10−5-1.62 × 10−3 and it was 4.03 × 10−5-1.96 × 10−4 due to 210Pb. The activity intake, effective dose and cancer risk was found lesser than international guidelines and the seafood intake was considered to be safe for human consumption. 相似文献
185.
Snow‐covered areas (SCAs) are the fundamental source of water for the hydrological cycle for some region. Accurate measurements of river discharge from snowmelt can help manage much needed water required for hydropower generation and irrigation purposes. This study aims to apply the snowmelt runoff model (SRM) in the Upper Indus basin by the Astore River in northern Pakistan for the years 2000 to 2006. The Shuttle Radar Topographic Mission (SRTM) data are used to generate the Digital Elevation Model (DEM) of the region. Various variables (snow cover depletion curves (SCDCs), temperature and precipitation) and parameters (degree‐day factor, recession coefficient, runoff coefficients, time lag, critical temperature and temperature lapse rate) are used as input in the SRM. However, snow cover data are direct and an important input to the SRM. Satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) are used to estimate the SCA. Normalized difference snow index (NDSI) algorithm is applied for snow cover mapping and to differentiate snow from other land features. Nash–Sutcliffe coefficient of determination (R2) and volume difference (DV) are used for quality assessment of the SRM. The results of the current research show that for the study years (2000–2006), the average value of R2 is 0·87 and average volume difference DV is 1·18%. The correlation coefficient between measured and computed runoff is 0·95. The results of the study further show that a high level of accuracy can be achieved during the snowmelt season. The simulation results endorse that the SRM in conjunction with MODIS snow cover product is very useful for water resource management in the Astore River and can be used for runoff forecasts in the Indus River basin in northern Pakistan. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
186.
Comparison of SDSM and LARS-WG for simulation and downscaling of extreme precipitation events in a watershed 总被引:12,自引:6,他引:6
Muhammad Zia Hashmi Asaad Y. Shamseldin Bruce W. Melville 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(4):475-484
Future climate projections of Global Climate Models (GCMs) under different emission scenarios are usually used for developing
climate change mitigation and adaptation strategies. However, the existing GCMs have only limited ability to simulate the
complex and local climate features, such as precipitation. Furthermore, the outputs provided by GCMs are too coarse to be
useful in hydrologic impact assessment models, as these models require information at much finer scales. Therefore, downscaling
of GCM outputs is usually employed to provide fine-resolution information required for impact models. Among the downscaling
techniques based on statistical principles, multiple regression and weather generator are considered to be more popular, as
they are computationally less demanding than the other downscaling techniques. In the present study, the performances of a
multiple regression model (called SDSM) and a weather generator (called LARS-WG) are evaluated in terms of their ability to
simulate the frequency of extreme precipitation events of current climate and downscaling of future extreme events. Areal
average daily precipitation data of the Clutha watershed located in South Island, New Zealand, are used as baseline data in
the analysis. Precipitation frequency analysis is performed by fitting the Generalized Extreme Value (GEV) distribution to
the observed, the SDSM simulated/downscaled, and the LARS-WG simulated/downscaled annual maximum (AM) series. The computations
are performed for five return periods: 10-, 20-, 40-, 50- and 100-year. The present results illustrate that both models have
similar and good ability to simulate the extreme precipitation events and, thus, can be adopted with confidence for climate
change impact studies of this nature. 相似文献
187.
A. Yu. Bundel V. N. Kryzhov Young-Mi Min V. M. Khan R. M. Vilfand V. A. Tishchenko 《Russian Meteorology and Hydrology》2011,36(3):145-154
The probability multimodel forecast system based on the Asia-Pacific Economic Cooperation Climate Center (APCC) model data is verified. The winter and summer seasonal mean fields T 850 and precipitation seasonal totals are estimated. To combine the models into a multimodel ensemble, the probability forecast is calculated for each of single models first, and then these forecasts are combined using the total probability formula. It is shown that the multimodel forecast is considerably more skilful than the single-model forecasts. The forecast quality is higher in the tropics compared to the mid- and high latitudes. The multimodel ensemble temperature forecasts outperform the random and climate forecasts for Northern Eurasia in the above- and below-normal categories. Precipitation forecast is less successful. For winter, the combination of single-model ensembles provides the precipitation forecast skill exceeding that of the random forecast for both Northern Eurasia and European Russia. 相似文献
188.
Prosanta Kumar Khan 《International Journal of Earth Sciences》2011,100(7):1749-1758
Present study addresses the role of major plate-driving forces, particularly the slab pull and slab resistive forces, for
the generation of 26 December 2004 M
w > 9.0 off Sumatra megathrust earthquake. Major controls on the plate-driving forces are normally visualized through age,
speed, and average dip of the slab during subduction. Wide variation in age, plate obliquity, stress obliquity, subduction
rate, dip angle, and flexing depth of the subducting oceanic lithosphere between Andaman and Sumatra thus allowed us for quantitative
evaluation of the slab pull (F
SP) and slab resistive (F
SR) forces in three well-defined sectors (I, II and III). Computed values of these forces in the three sectors: (1) F
SP = 1.29 × 1013 N/m, F
SR = 1.41 × 1013 N/m; sector I, (2) F
SP = 2.10 × 1013 N/m, F
SR = 1.13 × 1013 N/m; sector II, and (3) F
SP = 2.08 × 1013 N/m, F
SR = 2.72 × 1013 N/m; sector III clearly suggest a spatial variation of stress regime in the subducting oceanic lithosphere. Excess F
SR in sectors I and III are interpreted as the causative forces behind the triggering of major seismic energy bursts near Sumatra
and Andaman on 26 December 2004. A gap of minimum seismic energy burst near Great Nicobar possibly was controlled by the excess
of F
SP in sector II. This study further advocates that the cyclic stress, resulted from unbalanced component of slab resistive force,
had a definite control on the occurrence of 2004 off Sumatra megathrust earthquake around the flexing zone of the subducting
lithosphere. 相似文献
189.
For mineral resource assessment, techniques based on fuzzy logic are attractive because they are capable of incorporating uncertainty associated with measured variables and can also quantify the uncertainty of the estimated grade, tonnage etc. The fuzzy grade estimation model is independent of the distribution of data, avoiding assumptions and constraints made during advanced geostatistical simulation, e.g., the turning bands method. Initially, fuzzy modelling classifies the data using all the component variables in the data set. We adopt a novel approach by taking into account the spatial irregularity of mineralisation patterns using the Gustafson–Kessel classification algorithm. The uncertainty at the point of estimation was derived through antecedent memberships in the input space (i.e., spatial coordinates) and transformed onto the output space (i.e., grades) through consequent membership at the point of estimation. Rather than probabilistic confidence intervals, this uncertainty was expressed in terms of fuzzy memberships, which indicated the occurrence of mixtures of different mineralogical phases at the point of estimation. Data from different sources (other than grades) could also be utilised during estimation. Application of the proposed technique on a real data set gave results that were comparable to those obtained from a turning bands simulation. 相似文献
190.
GIS-based impact assessment of land-use changes on groundwater quality: study from a rapidly urbanizing region of South India 总被引:4,自引:0,他引:4
Haris H. Khan Arina Khan Shakeel Ahmed Jerome Perrin 《Environmental Earth Sciences》2011,63(6):1289-1302
This study attempts to assess the influence of changing land-use patterns on the groundwater quality of the hard rock aquifer
system in the Maheshwaram watershed, near Hyderabad, India. The study area is a rapidly urbanizing region with land development
progressing at a fast pace. To study the impact of this rapid urbanization and overall land-use transition, a groundwater
quality index (GQI) was prepared within a geographical information system (GIS). The GQI integrates the different water quality
parameters to give a final index value that can be used for spatio-temporal comparisons. The land-use transitions were closely
monitored from 2003 to 2008 using multispectral satellite images. The land-use pattern has changed drastically with an increase
in the built-up area at the expense of other land uses. The analysis reveals a rapid deterioration of groundwater quality
related mainly to the increase in built-up land with unsewered sanitation and poultry farms. Seasonal variability of the groundwater
quality was also assessed. Mean GQI decreased from 84.16 to 83.26 over a period of 5 years from 2003 to 2008, while seasonal
variability of water quality increased. GQI and Seasonal Variability of water quality were integrated in GIS to yield a groundwater
sustainability map, in terms of water quality. Zones of sustainable and unsustainable groundwater use were demarcated for
better decision making related to municipal land allotment in this rapidly urbanizing region. 相似文献