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Salim Lamine Sudhir Kumar Singh Szilárd Szabó Nour El Islam Bachari Prashant K. Srivastava 《国际地球制图》2018,33(8):862-878
This study aims to quantify the landscape spatio-temporal dynamics including Land Use/Land Cover (LULC) changes occurred in a typical Mediterranean ecosystem of high ecological and cultural significance in central Greece covering a period of 9 years (2001–2009). Herein, we examined the synergistic operation among Hyperion hyperspectral satellite imagery with Support Vector Machines, the FRAGSTATS® landscape spatial analysis programme and Principal Component Analysis (PCA) for this purpose. The change analysis showed that notable changes reported in the experimental region during the studied period, particularly for certain LULC classes. The analysis of accuracy indices suggested that all the three classification techniques are performing satisfactorily with overall accuracy of 86.62, 91.67 and 89.26% in years 2001, 2004 and 2009, respectively. Results evidenced the requirement for taking measures to conserve this forest-dominated natural ecosystem from human-induced pressures and/or natural hazards occurred in the area. To our knowledge, this is the first study of its kind, demonstrating the Hyperion capability in quantifying LULC changes with landscape metrics using FRAGSTATS® programme and PCA for understanding the land surface fragmentation characteristics and their changes. The suggested approach is robust and flexible enough to be expanded further to other regions. Findings of this research can be of special importance in the context of the launch of spaceborne hyperspectral sensors that are already planned to be placed in orbit as the NASA’s HyspIRI sensor and EnMAP. 相似文献
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地貌特征对约旦南部阿尔阿加河(WadiAl-Arja)流域产沙影响分析(英文) 总被引：1，自引：0，他引：1
Ali Hamdi ABU SALIM 《地理学报(英文版)》2014,24(3):457-474
This study addresses the morphometric variables that determine the sediment yield in Wadi Al-Arja through the analysis of the impact of different morphometric characteristics along the course of the valley on its sediment yield, as well as the analysis of spatial and formal dimensions and morphologies of the basin and its relationship to the sediment yield. The study also addresses the size of variation in the volume of sediment yield of the river tributaries that make up the water network of the valley under the differences of its morphometric and hydrological characteristics. The study found several results, most notably: The classification of Wadi Al-Arja basin according to the hypsometric integral value(72.1%) within an uneven topography, which increases the force of the erosive activity and the size of the sediment yield if the basin was exposed to moist climatic periods. The study also showed the presence of convergence in the intra-spaces between the river tributaries in the water network. This increases the volume of water flows when these tributaries meet with each other and thus increasing their erosive ability and sediment yield. The study also showed the presence of marked variation in the sediment yield of the river tributaries depending on the differences in its morphometric characteristics. The results of the step-wise regression analysis confirmed the importance of the morphometric and hydrological variables, and plant coverage in interpreting the variation in the size of the sediment yield of the river tributaries of different stream order in Wadi Al-Arja basin, where these variables interpreted 43% of the total variation, with statistical significance less than 0.05. 相似文献
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利用NOAA-AVHRR数据分析1982-2001年间中国植被的动态变化(英文) 总被引：1，自引：0，他引：1
The authors derived the normalized difference vegetation index (NDVI) from the NOAA/AVHRR Land dataset, at a spatial resolution of 8km and 15-day intervals, to investigate the vegetation variations in China during the period from 1982 to 2001. Then, GIS is used to examine the relationship between precipitation and the Normalized Difference Vegetation Index (NDVI) in China, and the value of NDVI is taken as a tool for drought monitoring. The results showed that in the study period, China’s vegetation cover h... 相似文献
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In this paper, we apply lagged correlation analysis to study the effects of vegetation cover on the summer climate in different zones of China, using NOAA/AVHRR normalized difference vegetation index (NDVI) data during the time period from 1982 to 2001 and climate data of 365 meteorological stations across China (precipitation from 1982 to 2001 and temperature from 1982 to 1998). The results show that there are positive correlations between spring NDVI and summer climate (temperature and precipitation) in m... 相似文献
5.
The Jurassic succession of western Iraq includes the Ubaid, Hussainiyat, Amij, Muhaiwir, and Najmah formations. Each formation is composed of basal clastic unit overlain by upper carbonate unit. Extensive and huge erosional unconformity occurred at the Triassic–Jurassic boundary due to marked shifting of structural (E–W) strike of the Triassic (Rhaetic) Zor Hauran Formation to (NE–SW) Jurassic formations. Sea level falling (lowstand system tracts) would result in the progradation of the land on the expense of the sea forming the recognizable progradation of the fluvial and deltaic deposits of the lower clastic units of the Jurassic formations, whereas sea level rising (highstand system tract), i.e., sea prograding, causes deposition of the carbonate units of the Jurassic formations system. This progradation resulted to various carbonate environments of deposition ranging from subtidal, intertidal, to supratidal. The main target on most of the exploration blocks in the western part of Iraq focused on the lower Paleozoic successions, whereas prospects in Triassic, Jurassic, and lower Cretaceous targets are less extensive but may have significant potential on certain blocks in both stratigraphic and structural traps. The western part of Iraq was subjected to intermittent pulses of uplifting (sea regression) and subsidence (sea transgression) to form the Jurassic basin system in the area. The Jurassic formations lack the characteristics of petroleum systems. In contrast, in the central and northern parts of Iraq, the Jurassic formations (Najmah and Gotnia formations) were deposited in subsiding basins in which the reservoir and sealed evaporitic rocks existed. In turn, in the western desert of Iraq, the Jurassic formations lack these petroleum system characteristics. Hence, it can be proposed that the petroleum–nonpetroleum inflection could be proposed in the east of area km 160. 相似文献
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P. C. Padhy R. K. Nayak V. K. Dadhwal M. Salim D. Mitra S. B. Chaudhury P. R. Rao K. H. Rao C.B. S. Dutt 《Journal of the Indian Society of Remote Sensing》2016,44(1):135-143
An empirical model is developed and used with remotely sensed predictors: sea surface temperature (SST) and chlorophyll-a concentration (Chl-a), to compute surface water partial pressure of carbon dioxide (pCO2w) and air-sea fluxes of CO2 in the Hooghly estuary and its adjacent coastal oceans. In situ observations used here were based on measurements carried out in this region during winter and summer periods in 2008. The estimated pCO2w compares well with the in situ observations at root mean square error ±18 μatm. In winter, estimated pCO2w ranges between 320 and 500 μatm with large values (>400 μatm) on the south-western and south-eastern flanks of the coastal domain and lower values (340–375 μatm) on the main-channel. In summer, it remained spatially uniform at 450 μatm. Extrapolation of the results over the study region based on the Moderate Imaging Specroradiometer (MODIS) measured SST and Chl-a suggests that the region is a strong source of atmospheric CO2 during the summer with net release of 0.095 Tg C year?1 (equivalent to mean flux of 90 molC m?2 year?1) and is a weak source during the winter with net release of 0.006 Tg C yr?1 (0.5 molC m?2 year?1) from the geographical extent of 6000 Km2 area. 相似文献
8.
Jaloul Bejaoui Mohamed Samaali Souad Baccouche Nafaa Regugui Mohamed Fethi Ben Hamouda Zohra Azzouz Adel Trabelsi Salah Bouhlel Boulamia Salim 《Arabian Journal of Geosciences》2013,6(7):2685-2689
In this study we investigate the radiological hazard of naturally occurring radioactive material in Tunisian and Algerian phosphorite deposits. Eight samples of phosphorite were collected from the phosphorite mines. The Tunisian and Algerian phosphorites occur in the Late Paleocene and Lower Eocene (Ypresian-Lutetian) in age (Béji Sassi 1984 and Zaïer 1999). Activity concentrations in all the samples were measured by alpha spectrometry and gamma spectrometry. Alpha spectrometry analyses show that the specific activity values of 238U, 234U and 235U in the samples of Tunisian phosphorite were 327?±?7 (321–327), 326?±?6 (325–331) and 14.50?±?0.72 (13.90–15.57) Bq kg?1, respectively. Specific activity measured by gamma spectrometry in the samples of the Tunisian and Algerian phosphorite shows a small difference. Specific activity levels of 40K, 226Ra, 232Th, 235U and 238U in the phosphorite samples from Tunisia were, respectively, 71.10?±?3.80, 391.54?±?9.39, 60.38?±?3.74, 12.72?±?0.54 and 527.42?±?49.57 Bq kg?1 and Algeria were 15.72?±?1.73, 989.65?±?12.52, 12.08?±?1.20, 47.50?±?1.52 and 1,148.78?±?7.30 Bq kg?1, respectively. The measured value of specific activity of 232Th and 40K in the Tunisian phosphorite samples is relatively higher than that found in the samples of Algerian phosphorite. The measured activity of uranium (238U) in the Tunisian phosphorite (527?±?49) Bq kg?1 is lower than in Algerian phosphorite. The measured activity of 238U in the Tunisian phosphorite samples was (527–1,315?±?65) 238U Bq kg?1 which is higher than its maximum background value of 110 Bq kg?1 in soils of the various countries of the world (Tufail et al. Radiat Meas 41:443–451, 2006). Different geological origins of phosphorites deposits are the main reason for the large spread in worldwide specific activities. The obtained results of uranium concentrations in phosphorites of different types (Algerian and Tunisian) demonstrate that the uranium concentrations are mainly governed by the phosphatic material. The present study reveals that phosphorite deposits contain natural radioactivity higher than background level. 相似文献
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Khadija Semhi Osman A. E. Abdalla Salah Al Khirbash Tabisam Khan Salim Asaidi Sardar Farooq 《Arabian Journal of Geosciences》2009,2(2):143-150
Groundwater samples from six wells and various species of plants from soils developed on ophiolites were collected from an arid area (AlKhod area, Oman) and analyzed for trace elements including rare earth elements (REEs). The distribution patterns of REEs in plants indicated an enrichment in middle REEs (MREEs?=?Sm to Dy) and heavy REEs (HREEs?=?Ho to Lu), when they are normalized to the REE composition of the Post Archean Australian Shale (PAAS), with a significant negative anomaly in Ce and a positive anomaly in Eu. Compared to Oman ophiolites, the REEs in different species of plants are depleted in Ce and enriched in MREEs and slightly enriched in light REE (LREE?=?from La to Nd). Relative to PAAS, the distribution of REEs in groundwaters revealed similar patterns to the REE distribution in plants. The distribution patterns of REEs in plants relative to those in waters are nearly flat. These patterns suggest that the transfer of REEs from soil solutions to the groundwaters in Oman occurs without any significant fractionation. 相似文献
10.
Determination of the origin of mineralization and groundwater salinity in the Adrar region in the southwest of Algeria 
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下载免费PDF全文 KHELFAOUI Hakim DAJBRI Larbi LAKHAL Fatima Zohra CHAFFAI Hicham HANI Azzedine SAYAD Lamine 《地下水科学与工程》2020,8(2):158-171
To some extent, the sedimentary sequence with the largest groundwater reserves in northern Sahara is marked by a certain water table level, regionally known as the "Continental Intercalaire"(CI). "Continental Intercalaire"(CI) refers to "Continental Intercalary" widely distributed among three countries. Algeria, Tunisia and Libya, which have significant potential of water resources. As it is the only water resource relatively easily accessible to the inhabitants of the Sahara, it is widely developed. The physico-chemical characteristics of statistical processing in principal component analysis(PCA) and the chemical phase measurement of groundwater in the unconfined aquifer captured by "Foggaras"(traditional system irrigation composed of well system linked by a horizontal channel from their bases) and the deep drillings located in the study area were accessible. Therefore, there were some favorable conditions for comparing the chemistry of these waters with the standards of potability established by the World Health Organization. Then, the study detected the origin of excessive mineralization and the excessive content of Na, Cl, K, Mg and Ca that originated from the leaching of the clay and carbonate layers of the "Continental Intercalaire". In addition, the enrichment in NO_2~-, NO_3~- and SO_4~(2-) was due to the excessive use of fertilizer in the whole region for shallower Foggaras waters, and this study also showed the dominant chemical facies of groundwater related to the significant abundance of these mineral salts in this thick aquifer horizon. 相似文献