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With a view to difficulties with explaining the physical mechanism of solar forcing on the Earth’s climate, we applied a new
approach of determining and quantifying an influence of solar-related events on water vapor variability by correlating the
total electron content (TEC) and precipitable water vapor (PWV), both derived from ground-based GPS observations.
In this study, ionospheric TEC and atmospheric PWV values are employed as solar activity and terrestrial climate parameters,
respectively. Three-year GPS data at five stations in Antarctica are analyzed on a daily mean basis. Results show significant
correlation between TEC and PWV differences during storms-affected days. The high correlation between the daily mean values
of TEC and PWV, both of which follow the seasonal signals and subsisting downward trend, suggests an influence of solar activity
on climate variability in Antarctica. These quantities are determined by changes of the upper-atmosphere level, which varies
in conformity with the zenith angle of the Sun. 相似文献
94.
Aziz Ghaderpour Khairul Nazrin Mohd Nasori Li Lee Chew Ving Ching Chong Kwai Lin Thong Lay Ching Chai 《Marine pollution bulletin》2014
The deltaic estuarine system of the Matang Mangrove Forest Reserve of Malaysia is a site where several human settlements and brackish water aquaculture have been established. Here, we evaluated the level of fecal indicator bacteria (FIB) and the presence of potentially pathogenic bacteria in the surface water and sediments. Higher levels of FIB were detected at downstream sampling sites from the fishing village, indicating it as a possible source of anthropogenic pollution to the estuary. Enterococci levels in the estuarine sediments were higher than in the surface water, while total coliforms and E. coli in the estuarine sediments were not detected in all samples. Also, various types of potentially pathogenic bacteria, including Klebsiella pneumoniae, Serratia marcescens and Enterobacter cloacae were isolated. The results indicate that the Matang estuarine system is contaminated with various types of potential human bacterial pathogens which might pose a health risk to the public. 相似文献
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96.
The following work aims at minimizing the environmental impact of the solid wastes (ash) that is produced after the utilization
of the bituminous limestone in thermal power stations and/or retorting processes. The laboratory tests have been selected
with respect to construction needs and possible post construction conditions. Utilization of the various types of ash in the
production of lightweight concrete block has revealed optimum results. The compressive strength of various ash–glass sand
mixes has ranged between 19 and 76 kg/cm2 at 28 days. The compressive strength of ash–tuff mixes has ranged between 54 and 63 kg/cm2 at 28 days. Ultra light mixtures using ash–polyester with a density of 0.88 kg/m3 and a compressive strength of 21 kg/cm2 at 28 days are produced at normal room curing temperature without the use of ordinary Portland cement. The high alkalinity
of El-Lajjun ash is considered a disadvantage when utilized in normal concrete mixes for structural purposes. Ash only can
be mixed with aggregates to produce lean concrete for blinding purposes for use in foundations. 相似文献
97.
Surface drainage sediments were collected, between January and April in 2005, from 6 sampling sites in Peninsular Malaysia suspected to have received different anthropogenic sources. These drainages included sites near a petrochemical plant, an electronic factory, a metal factory and 2 townships in addition to a relatively unpolluted site (a reference site). Based on the aqua-regia method, the metal concentrations for all the sampling sites except for the agricultural site (reference site) at Sg. Benut were between 60.92-1 019 μg/g dry weight for copper (Cu), 65.32-1 266.6μg/g dry weight for plumbum (Pb), 1.46-15.93 μg/g dry weight for cadmium (Cd), 330.10-484.14 μg/g dry weight for zinc (Zn) and 47.03-120.90 μg/g dry weight for nickel (Ni). All of these ranges were significantly (p< 0.05) higher than those (Cu: 8.77 μg/g; Pb: 57.42 μg/g; Cd: 0.96 μg/g; Zn: 68.21 μg/g; and Ni: 17.87 μg/g) of the reference site at Sg. Benut that only received agricultural disposal. The concentrations for the 5 metals from all the sites (except for the reference site) were higher than the Sediment Quality Values for Hong Kong by Chapman et al (1999) for the 5 metals. Based on the sequential extraction technique, 3 geochemical fractions [easily, freely leachable and exchangeable (EFLE), acid-reducible and oxidisable-organic] were also useful in identifying these polluted sites. The elevated metal concentrations found in the sediments might be related to point sources of industrial effluent and urban waste. Hence, the results emphasized the necessity for the treatment of effluents into this drainage area. As part of the effort to control illegal discharges and dumping into drainages, public awareness should be enhanced. 相似文献
98.
The sustainable management and monitoring of urban forests is an important activity in the urbanized world, and operational approaches require information about the status of urban trees to determine the best strategy. One limitation in urban forest studies is the detection and discrimination of tree species using limited training data. Thus, this study focuses on developing generic rule sets from high-resolution WorldView-2 imagery in conjunction with spectral, spatial, colour and textural information for automated urban tree species detection. The object-based image analysis and its combination with statistical analysis of object features is utilized for this purpose. Results of attribute selection indicated that from 55 attributes, only 26 were useful to discriminate urban tree species, namely Messua ferrea L., Samanea saman and Casuarina sumatrana. Finally, the high overall accuracy, approximately 86.87% with kappa of 0.75 confirmed the transferability of the generic model. 相似文献
99.
Anuar Sefie Ahmad Zaharin Aris Mohammad Firuz Ramli Tahoora Sheikhy Narany Mohd Khairul Nizar Shamsuddin Syaiful Bahren Saadudin Munirah Abdul Zali 《Environmental Earth Sciences》2018,77(10):397
Continual expansion of population density, urbanization, agriculture, and industry in most parts of the world has increased the generation of pollution, which contributes to the deterioration of surface water quality. This causes the dependence on groundwater sources for their daily needs to accumulate day by day, which raises concerns about their quality and hydrogeochemistry. This study was carried out to increase understanding of the geological setup and assess the groundwater hydrogeochemical characteristics of the multilayered aquifers in Lower Kelantan Basin. Based on lithological data correlation of exploration wells, the study area can be divided into three main aquifers: shallow, intermediate and deep aquifers. From these three aquifers, 101 groundwater samples were collected and analyzed for various parameters. The results showed that pH values in the shallow, intermediate and deep aquifers were generally acidic to slightly alkaline. The sequences of major cations and anions were Na+ > Ca2+ > Mg2+ > K+ and HCO3? > Cl? > SO42? > CO32?, respectively. In the intermediate aquifer, the influence of ancient seawater was the primary factor that contributed to the elevated values of electrical conductivity (EC), Cl? and total dissolved solids (TDS). The main facies in the shallow aquifer were Ca–HCO3 and Na–HCO3 water types. The water types were dominated by Na–Cl and Na–HCO3 in the intermediate aquifer and by Na–HCO3 in the deep aquifer. The Gibbs diagram reveals that the majority of groundwater samples belonged to the deep aquifer and fell in the rock dominance zone. Shallow aquifer samples mostly fell in the rainfall zone, suggesting that this aquifer is affected by anthropogenic activities. In contrast, the results suggest that the deep aquifer is heavily influenced by natural processes. 相似文献
100.
Ernieza Suhana Mokhtar Biswajeet Pradhan Abd Halim Ghazali Helmi Zulhaidi Mohd Shafri 《Arabian Journal of Geosciences》2018,11(21):682
Water discharge is the main parameter in hydraulic modeling for flood hazard assessment. However, the unavailability of data on discharge and observed river morphologies resulted in erroneous calculations and irregularities in flood inundation mapping. The objectives of this study are (i) to investigate uncertainties of hydraulic parameters (width, cross-sectional depth, and channel slope) used in discharge equation and (ii) to examine the influence of estimate discharge on water extent and flood depth with different boundary conditions on interferometric synthetic aperture radar (IFSAR) and modified IFSAR DEMs. Sensitivity analysis was conducted with the Monte Carlo simulation method to generate random data combinations. Bjerklie’s equation was used to calculate discharge based on the three variables, and Manning’s n was substituted into the Hydrologic Engineering Center River Analysis System (HEC-RAS) model. TerraSAR-X was used to distinguish existing flood water bodies and normal water extent. The uncertainty of the combined variables was assessed with the likelihood measures such as F-statistic, mean absolute error, root mean square error, and Nash–Sutcliffe efficiency which compares observed and predicted inundated area as well as flood water depth simulated using the HEC-RAS model. 相似文献