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41.
There is a high degree of uncertainty about the state and fate of Pakistan's Karakoram glaciers due to data scarcity in high altitude regions. They are thought to be less vulnerable to climatic change because they behave differently as compared with eastern Himalayas. This study measures the decadal temporal changes in the glacial ice area of Karakoram's Hunza River Basin, one of the eight subbasins of Upper Indus Basin. An attempt has been made to investigate the relationship between glacial ice area changes and calculated values of precipitation, temperature and run‐off. A combination of satellite and field‐based approach is applied. Output includes maps of glacial ice hypsometries of eight glacial ice subregions of Hunza River Basin for 3 years (i.e., 1989, 2002, and 2010). The results show a decreasing trend in the glacial ice‐covered area signifying a reduction of 20.47% with the largest reduction being in the lower elevation bands. There is presently no conclusive answer as to why glacial ice in the Karakoram is acting differently from the near‐global indication of glacial ice changes. Climate data from high altitudes are needed to find answer for this anomalous behaviour.  相似文献   
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Tillage systems affect soil properties, crop growth and nutrient uptake under various agro-ecological conditions. The uptake of water and nutrients are largely dependent on the root systems of wheat (Triticum aestivum L.) and rice (Oryza sativa L.). The application of manure has direct influence on the nutrient uptake by the crop plants. A 2 year field experiment was conducted to evaluate the impact of tillage and farm manure on root growth by measuring the root length density on a sandy clay loam (Typic calciargid soil). Three tillage systems were used; (i) minimum tillage (MT), (ii) deep tillage (DT) and (iii) conventional tillage (CT). Three farm manure levels were used; (i) FM0 (only chemical fertilizers), (ii) FM15 (farm manure at 15 Mg ha?1) and (iii) FM30 (farm manure at 30 Mg ha?1). The incorporation of farm manure into soil markedly improved the root length density (RLD) of both wheat and rice crops. For wheat, the application of FM30 increased RLD by 16% and 9% in cases of deep tillage and minimum tillage, respectively. For rice, the increase in RLD at the same farm manure rate (FM30) was 13% and 17%, during first and second year, respectively. Averaged across tillage, the trend of RLD for both wheat and rice was DT > CT > MT. The incorporation of FM has increased the uptake of N, P and K significantly (P < 0.05), thereby increasing the agronomic parameters. The manure may be used to ameliorate the deleterious effects of tillage for sustainable crop yield.  相似文献   
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Organic geochemical and palynofacies analyses were carried out on shale intervals of the Late Paleocene Patala Formation at Nammal Gorge Section, western Salt Range, Pakistan. The total organic carbon content and Rock-Eval pyrolysis results indicated that the formation is dominated by type II and type III kerogens. Rock-Eval \({T}_{\mathrm{max}}\) vs. hydrogen index (HI) and thermal alteration index indicated that the analysed shale intervals present in the formation are thermally mature. \(S_{1}\) and \(S_{2}\) yields showed poor source rock potential for the formation. Three palynofacies assemblages including palynofacies-1, palynofacies-2 and palynofacies-3 were identified, which are prone to dry gas, wet gas and oil generation, respectively. The palynofacies assessment revealed the presence of oil/gas and gas prone type II and type III kerogens in the formation and their deposition on proximal shelf with suboxic to anoxic conditions. The kerogen macerals are dominated by vitrinite and amorphinite with minor inertinite and liptinite. The kerogen macerals are of both marine and terrestrial origin, deposited on a shallow shelf. Overall, the dark black carbonaceous shales present within the formation act as a source rock for hydrocarbons with poor-to-moderate source rock quality, while the grey shales act as a poor source rock for hydrocarbon generation.  相似文献   
46.
The Pirkoh and Drazinda formations in the Sulaiman Range, central Pakistan, yielded assemblages of (early) Bartonian orthophragminids, characterized predominantly by discocyclinids with a significant number of species probably endemic to Indian Subcontinent. The rarity of Asterocyclina and the absence of Orbitoclypeus and Nemkovella are noteworthy. Ten species of Discocyclina Gümbel and two species of Asterocyclina Gümbel, referable to the Shallow Benthics Zone (SBZ) 17 are described for the first time from Pakistan. The discocyclinids, i.e. Discocyclina praeomphalus, D. sulaimanensis, D. kutchensis, along with the new taxa established here, D. zindapirensis sp. nov., D. rakhinalaensis sp. nov., and D. pseudodispansa sp. nov., seem to be confined to the Indo-Pakistani region (Eastern Tethys). The Discocyclina dispansa, D. discus, D. nandori, and D. augustae lineages known from Western Tethys are also common in the Indian Subcontinent, as are asterocyclinids, such as Asterocyclina sireli and A. stellata. The upper part of the Drazinda Formation (‘Pellatispira beds’), referable to latest Bartonian and/or the early Priabonian, is poor in orthophragminids and is characterized by the occurrence of reticulate Nummulites, Heterostegina, Pellatispira and Silvestriella. The records of ‘Lepidocyclina of Caribbean affinity’ with large embryons from the Eocene of the Indian Subcontinent correspond to misidentified Discocyclina discus.  相似文献   
47.
The aim of this study is finding suitable locations for ecotourism development in Cox’s Bazar, Bangladesh. For this, potential ecotourism sites were identified and ranked using Geographical Information System and Analytical Hierarchy Process. Five factors and 15 criteria were identified to evaluate suitability of sites. Factors and criteria were selected based on literature review, local knowledge and experts’ opinions. Considering the national and international contexts and effects of ecotourism, this study proposes treating highly suitable areas more ‘naturally’ and, for conservation programmes, creating tourist facilities in moderately suitable areas by targeting growth centres and protecting agricultural land as well as local primary activities in marginally suitable areas.  相似文献   
48.
伊犁河谷是新疆地区暴雨多发且暴雨强度最强的地区。本文以该地区的一次特大暴雨过程为例,利用观测资料以及WRF高分辨率数值模拟结果对该次暴雨过程的环流背景及不稳定条件进行了分析。结果表明:(1)此次降水过程发生在对流层高层南亚高压“双体型”,中层中高纬度“两脊一槽”以及两个中亚低涡发展移动的环流形势下。在伊犁河谷特殊的向西开口的喇叭口地形作用下,中心位于哈萨克斯坦的中亚低涡导致伊犁河谷低层为偏西风,中心位于塔里木盆地的中亚低涡使得伊犁河谷中层为偏东风,导致伊犁河谷内中低层水平风的垂直切变增强;伊犁河谷内,地形及哈萨克斯坦中亚低涡环流的共同作用形成了低空辐合线,辐合线附近形成的辐合区正好与高空急流辐散区垂直叠加,引发河谷内的上升运动增强。低层西风将水汽输送进河谷,并在河谷内迎风坡附近堆积,上升运动增强后导致河谷内堆积的水汽得以抬升。(2)WRF模拟结果分析显示,散度分布、垂直风切变、水汽及热力层结分布等对降水产生均有重要贡献。通过对湿位涡垂直及水平分量的分析得出热力层结影响的对流不稳定对前期降水的产生有影响,同时,垂直风切变影响的对称不稳定对降水增强维持有重要作用。位势散度分析进一步指示出整个降水区低层的对流不稳定主要是由于位势散度的垂直切变部分造成,而位势散度的散度部分能加强河谷内小地形背风坡处的对流不稳定,说明整个降水演变过程中,动热力因子的相互作用共同影响了降水强度和落区。  相似文献   
49.
The successful exploration and production of shale-gas resources in the United States and Canada sets a new possible solution towards the energy crisis presently affecting most countries of Asia. This study focuses on the use of well log and 2D seismic data for the characterization of the shale oil/gas potential of a Paleocene–Eocene succession — the Meyal area in the Potwar Basin of Pakistan. Two shaly plays are identified in Paleocene–Eocene strata in well logs using ΔLogR and modified ΔLogR cross-plot techniques. The results indicate that Paleocene shale(the Patala Formation) and the lower shaly part of Eocene limestone(Sakesar Formation) can be potentially mature source rocks. However, the thermal maturity modelling proves that only the Paleocene shale is mature. Our results also suggest that the maturity responses on ΔLogR models for the lower shaly part of the Eocene limestone are due to trapped hydrocarbons in the intra-formational fractures. Petroelastic/petrophysical analysis of the Patala Formation reveals two potential shale oil/gas zones on the basis of Young's modulus, Poisson's ratio, Brittleness index and Total Organic Content at an exploitation depth of 3980–3988 m. This work can provide valuable insight for estimating shale oil/gas potential in highly deformed basins not only in Asia but in other parts of the world.  相似文献   
50.
To obtain the shear wave velocity profile for engineering application to near-subsurface, many geophysical techniques are used. The dispersion curve alone is unable to provide deeper shear wave velocity information for deep soil deposit; therefore, a joint inversion of dispersion curves with the horizontal over vertical (H/V) (i.e., apparently ellipticity) curve is recommended. The H/V curve obtained from the microtremor recording contains a major part of Love wave contribution to the noise wavefield horizontal component. Due to this presence of Love wave fraction, the H/V curve does not completely replicate the ellipticity of Rayleigh wave. In this study, we try to compare the Rayleigh wave ellipticity obtained from the borehole velocity model to the H/V curve obtained at the same locality from seismic ambient noise recording. Two different techniques available for the Love effect minimization are tested and compared with the borehole ellipticity. Finally, the joint inversion of H/V and dispersion curve is made, which shows great correspondence with the previous measurement at the site.  相似文献   
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