Spatial patterns and temporal trends of daily precipitation indices in Iran     

Tayeb Raziei  Jamal Daryabari  Isabella Bordi  Reza Modarres  Luis S. Pereira 《Climatic change》2014,124(1-2):239-253

Spatial patterns of daily precipitation indices and their temporal trends over Iran are investigated using the APHRODITE gridded daily precipitation dataset for the period 1961–2004. The performance and limitations of the gridded dataset are checked against observations at ten rain-gauge stations that are representative of different climates in Iran. Results suggest that the spatial patterns of the indices reflect the role of orography and sea neighborhoods in differentiating central-southern arid and semi-arid regions from northern and western mountainous humid areas. It is also found that western Iran is impacted by the most extreme daily precipitation events occurring in the country, though the number of rainy days has its maximum in the Caspian Sea region. The time series of precipitation indices is checked for long-term trends using the least squares method and Mann-Kendall test. The maximum daily precipitation per year shows upward trends in most of Iran, though being statistically significant only in western regions. In the same regions, upward trends are also observed in the number of wet days and in the accumulated precipitation and intensity during wet days. Conversely, the contribution of precipitation events below the 75th percentile to the annual total precipitation is decreasing with time, suggesting that extreme events are responsible for the upward trend observed in the total annual precipitation and in the other indices. This tendency towards more severe/extreme precipitation events, if confirmed by other datasets and further analyses with longer records, would require the implementation of adequate water resources management plans in western Iran aimed at mitigating the increasing risk of intense precipitation and associated flash floods and soil erosion.  相似文献   

Geoelectrical and hydrochemical investigations for characterizing the salt water intrusion in the Khanasser valley, northern Syria   总被引：1，自引：1，他引：0  

Jamal Asfahani  Boulos Abou Zakhem 《Acta Geophysica》2013,61(2):422-444

An integrated approach of geoelectrical and hydrochemical investigation surveys was proposed for indicating contact regions between saline and fresh groundwater in the Khanasser valley region, northern Syria. The qualitative and quantitative interpretations of 34 vertical electrical soundings (VES) enable to characterize the salt water intrusion laterally and vertically. The established iso-apparent resistivity maps for different AB/2 spacings obviously indicate the presence of a lowresistivity (less than 4 Ohm·m) zone related to the salt water intrusion in the Quaternary and Paleogene deposits. The different hydrochemical and geophysical parameters, such as electrical resistivity, total dissolved solids (TDS) and major ions concentrations used to characterize the salt water intrusion gave almost similar results in locating and mapping the different boundaries of the groundwater salinity. The proposed approach is useful for mapping the interface between different groundwater qualities, and can be therefore used to successfully characterize the salt water intrusion phenomenon in other semi-arid regions. The application of such an approach is a powerful tool and can be used for water resource management in the water scarce areas.  相似文献   

Fine-resolution population mapping using OpenStreetMap points-of-interest   总被引：1，自引：0，他引：1  

Mohamed Bakillah  Steve Liang  Amin Mobasheri  Jamal Jokar Arsanjani  Alexander Zipf 《International journal of geographical information science》2014,28(9):1940-1963

Data on population at building level is required for various purposes. However, to protect privacy, government population data is aggregated. Population estimates at finer scales can be obtained through areal interpolation, a process where data from a first spatial unit system is transferred to another system. Areal interpolation can be conducted with ancillary data that guide the redistribution of population. For population estimation at the building level, common ancillary data include three-dimensional data on buildings, obtained through costly processes such as LiDAR. Meanwhile, volunteered geographic information (VGI) is emerging as a new category of data and is already used for purposes related to urban management. The objective of this paper is to present an alternative approach for building level areal interpolation that uses VGI as ancillary data. The proposed method integrates existing interpolation techniques, i.e., multi-class dasymetric mapping and interpolation by surface volume integration; data on building footprints and points-of-interest (POIs) extracted from OpenStreetMap (OSM) are used to refine population estimates at building level. A case study was conducted for the city of Hamburg and the results were compared using different types of POIs. The results suggest that VGI can be used to accurately estimate population distribution, but that further research is needed to understand how POIs can reveal population distribution patterns.  相似文献   

Solving non-linear Lane–Emden type equations using Bessel orthogonal functions collocation method     

Kourosh Parand  Mehran Nikarya  Jamal Amani Rad 《Celestial Mechanics and Dynamical Astronomy》2013,116(1):97-107

The Lane–Emden type equations are employed in the modeling of several phenomena in the areas of mathematical physics and astrophysics. These equations are categorized as non-linear singular ordinary differential equations on the semi-infinite domain $[0,\infty )$ . In this research we introduce the Bessel orthogonal functions as new basis for spectral methods and also, present an efficient numerical algorithm based on them and collocation method for solving these well-known equations. We compare the obtained results with other results to verify the accuracy and efficiency of the presented scheme. To obtain the orthogonal Bessel functions we need their roots. We use the algorithm presented by Glaser et al. (SIAM J Sci Comput 29:1420–1438, 2007) to obtain the $N$ roots of Bessel functions.  相似文献   

Mixture distributions - an alternative approach for estimating maximum magnitude earthquake occurrence     

Khalid J. Fahmi  Jamal N. Al  Abbasi 《Geophysical Journal International》1987,89(2):741-747

Summary. Gumbel's theory of extreme value has been employed in the statistical forecasting of maximum-magnitude earthquake occurrence. The basic working hypothesis behind this method assumes that observations follow either Gumbel type I or type III asymptotic distributions. In certain cases, however, it is found that neither type of distribution fits the data well enough to produce accurate parameter-estimates, particularly in the larger earthquake range. This article proposes an alternative approach based on finite-mixture distributions whereby a more realistic prediction of upper earthquake magnitudes (at given return periods) is expected using a combined analysis of both Gumbel types I and III extremal distributions.  相似文献   

Phytotoxic effect of aluminum and chromium on the germination and early growth of wheat (Triticum aestivum) varieties Anmol and Kiran     

S. N. Jamal  M. Z. Iqbal  M. Athar 《International Journal of Environmental Science and Technology》2006,3(4):411-416

A greenhouse experiment was conducted to determine the phytotoxic effect of aluminum and chromium on the germination and early growth of two wheat (Triticum aestivum) varieties Anmol and Kiran. Seed were treated with 40, 80, 120 and 160 ppm of aluminum and chromium solution individually and in combined form. Observations were made on seed germination, root, shoot and seedling length, and dry biomass. Seed germination and dry biomass showed no effect of aluminum, chromium and combined treatment. Root, shoot and seedling length of both the varieties showed significant (P<0.05) decrease as compared to control. The growth was also reduced as the concentration of aluminum and chromium increased. Seedling length decreased in both the varieties at all the concentration of different treatment of aluminum, chromium and combined treatment. Attempts are being made in different laboratories to construct novel plants using genetic manipulation technologies that may have a greater tolerance to the presence of toxic metals. The results of the present study may help in understanding the mechanisms involved and their possible use in pytoremediation.  相似文献   

Effect of aluminum and chromium on the growth and germination of mesquite (Prosopis juliflora swartz.) DC.     

Sh. N. Jamal B.Sc.  M.Sc.  M. Z. Iqbal B.Sc.  M.Sc.  Ph.D.  M. Athar M.Sc.  M.Phil.  Ph.D.  D.Sc. 《International Journal of Environmental Science and Technology》2006,3(2):173-176

Prosopis seeds were grown under controlled environment in solution of aluminum and chromium at different concentration alone as well as combined together. The effect of these metals was studied on seed germination, root length, shoot length, seedling length and dry biomass. Aluminum and chromium alone, and combined together showed no effects on germination and dry biomass. Chromium alone was found toxic to root, shoot and seedling length. However, application of different concentrations of aluminum increased the root, shoot and seedling growth. It may be concluded that aluminum is not as toxic as chromium, and their combined treatment showed the intermediate effect by ameliorating the impact of one another.  相似文献   

A comparative study of various commercially available programs in slope stability analysis   总被引：1，自引：0，他引：1  

Wael Alkasawneh  Abdallah I. Husein Malkawi  Jamal Hassan Nusairat  Nermeen Albataineh   《Computers and Geotechnics》2008,35(3):428-435

The objective of this paper is to study the effect of different slip surface search techniques on the factors of safety obtained using the limit equilibrium (LE) slope stability methods. This objective is accomplished by comparing results from the finite element method, the linear grid method, the rectangular grid method, and the Monte-Carlo searching techniques using different commercially available programs. The results showed that the LE methods are very efficient methods when coupled with a robust searching technique namely the Monte-Carlo method. In addition, the selected slip surface search technique highly influenced the location of the critical slip surfaces as well as the value of the calculated factors of safety.  相似文献   

Assessing the suitability of GlobeLand30 for mapping land cover in Germany     

Jamal Jokar Arsanjani  Linda See  Amin Tayyebi 《International Journal of Digital Earth》2016,9(9):873-891

Global land cover (LC) maps have been widely employed as the base layer for a number of applications including climate change, food security, water quality, biodiversity, change detection, and environmental planning. Due to the importance of LC, there is a pressing need to increase the temporal and spatial resolution of global LC maps. A recent advance in this direction has been the GlobeLand30 dataset derived from Landsat imagery, which has been developed by the National Geomatics Center of China (NGCC). Although overall accuracy is greater than 80%, the NGCC would like help in assessing the accuracy of the product in different regions of the world. To assist in this process, this study compares the GlobeLand30 product with existing public and online datasets, that is, CORINE, Urban Atlas (UA), OpenStreetMap, and ATKIS for Germany in order to assess overall and per class agreement. The results of the analysis reveal high agreement of up to 92% between these datasets and GlobeLand30 but that large disagreements for certain classes are evident, in particular wetlands. However, overall, GlobeLand30 is shown to be a useful product for characterizing LC in Germany, and paves the way for further regional and national validation efforts.  相似文献   

Review of Ground Characterization by Using Instrumented Drills for Underground Mining and Construction   总被引：1，自引：0，他引：1  

Sair Kahraman  Jamal Rostami  Ali Naeimipour 《Rock Mechanics and Rock Engineering》2016,49(2):585-602

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