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Comprehensive analysis of glacier recession(2000-2020)in the Nun-Kun Group of Glaciers,Northwestern Himalaya

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Journal of mountain Science 2024年第3期21卷 768-785页

作者： shakil Ahmad ROmSHOO Ummer AmEEN mustafa Hameed BHAT Tariq ABDULLAH Department of Geoinformatics University of KashmirSrinagarKashmir 190006India Islamic University of Science and Technology AwantiporaKashmir 192122India Centre of Excellence for Glacier Studies in the Western Himalaya University of KashmirSrinagarKashmir 190006India

Himalayan glaciers are shrinking rapidly,especially after *** shrinkage,however,shows a differential pattern in space and time,emphasizing the need to monitor and assess glacier changes at a larger *** this study,changes of 48 glaciers situated around the twin peaks of the Nun and Kun mountains in the northwestern Himalaya,hereafter referred to as Nun-Kun Group of Glaciers(NKGG),were investigated using Landsat satellite data during *** in glacier area,snout position,Equilibrium Line Altitude(ELA),surface thickness and glacier velocity were assessed using remote sensing data supplemented by field *** study revealed that the NKGG glaciers have experienced a recession of 4.5%±3.4%and their snouts have retreated at the rate of 6.4±1.6 m·a^(-1).Additionally,there was a 41%increase observed in the debris cover area during the observation *** the geodetic approach,an average glacier elevation change of-1.4±0.4 m·a^(-1)was observed between 2000 and *** observed mass loss of the NKGG has resulted in the deceleration of glacier velocity from 27.0±3.7 m·a^(-1)in 2000 to 21.2±2.2 m·a^(-1)in *** ELA has shifted upwards by 83.0±22 m during the *** morphological and topographic factors showed a strong influence on glacier ***,a higher recession of 12.9%±3.2%was observed in small glaciers,compared to 2.7%±3.1%in larger *** debris-covered glaciers showed lower shrinkage(2.8%±1.1%)compared to the clean glaciers(9.3%±5%).The glacier depletion recorded in the NKGG during the last two decades,if continued,would severely diminish glacial volume and capacity to store water,thus jeopardizing the sustainability of water resources in the basin.

关键词： Nun-Kun range Glacier recession Glacier snout Remote Sensing Himalaya Glacier velocity

Theoretical calculations of structural, electronic, and elastic properties of CdSe_(1-x)Te_x:A first principles study

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Chinese Physics B 2016年第7期25卷 324-330页

作者： m shakil muhammad Zafar Shabbir Ahmed muhammad Raza-ur-rehman Hashmi m A Choudhary T Iqbal Department of Physics Hafiz Hayat Campus University of Gujrat Simulation Laboratory Department of Physics the Islamia University of Bahawalpur

The plane wave pseudo-potential method was used to investigate the structural, electronic, and elastic properties of Cd Se_（1-x）Te_x in the zinc blende phase. It is observed that the electronic properties are improved considerably by using LDA ＋ U as compared to the LDA approach. The calculated lattice constants and bulk moduli are also comparable to the experimental results. The cohesive energies for pure Cd Se and Cd Te binary and their mixed alloys are calculated. The second-order elastic constants are also calculated by the Lagrangian theory of elasticity. The elastic properties show that the studied material has a ductile nature.

关键词： first principles calculations density functional theory II–VI semiconductors structural electronic and elastic properties

Theoretical investigation of sulfur defects on structural, electronic,and elastic properties of ZnSe semiconductor

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Chinese Physics B 2015年第7期24卷 365-370页

作者： muhammad Zafar Shabbir Ahmed m.shakil m.A.Choudhary K.mahmood Simulation Laboratory Department of PhysicsThe Islamia University of Bahawalpur 63100Pakistan Department of Physics GC UniversityFaisalabad 68000Pakistan

The structural, electronic, and elastic properties of ZnSe1-xSx for the zinc blende structures have been studied by using the density functional theory. The calculations were performed using the plane wave pseudopotential method, as implemented in Quantum ESPRESSO. The exchange-correlation potential is treated with the local density approximation pz-LDA for these properties. moreover, LDA＋U approximation is employed to treat the ＂d＂ orbital electrons properly. A comparative study of the band gap calculated within both LDA and LDA＋U schemes is presented. The analysis of results show considerable improvement in the calculation of band gap. The inclusion of compositional disorder increases the values of all elastic constants. In this study, it is found that elastic constants C11, C12, and C44 are mainly influenced by the compositional disorder. The obtained results are in good agreement with literature.

关键词： first principles calculations density functional theory II–VI semiconductors electronic and elastic properties

First-principles calculation of the structural,electronic,and magnetic properties of cubic perovskite RbXF3(X = mn,V,Co,Fe)

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Chinese Physics B 2016年第11期25卷 486-491页

作者： muhammad Raza ur rehman Hashmi muhammad Zafar m shakil Atif Sattar Shabbir Ahmed S A Ahmad Simulation Laboratory Department of Physics The Islamia University of Bahawalpur 63100 Pakistan Department of Physics Hafiz Hayat Campus University of Gujrat Gujrat Pakistan

First-principles calculations by means of the full-potential linearized augmented plane wave method using the generalized gradient approximation with correlation effect correction（GGA＋U） within the framework of spin polarized density functional theory（DFT＋U） are used to study the structural,electronic,and magnetic properties of cubic perovskite compounds RbXF3（X = mn,V,Co,and Fe）.It is found that the calculated structural parameters,i.e.,lattice constant,bulk modulus,and its pressure derivative are in good agreement with the previous *** results reveal that the strong spin polarization of the 3d states of the X atoms is the origin of ferromagnetism in *** energies and the magnetic moments of RbXF3 have also been *** calculated electronic properties show the half-metallic nature of RbCoF3 and RbFeF3,making these materials suitable for spintronic applications.

关键词： cubic metallic perovskite modulus correction linearized ferromagnetic augmented instance spheres

Paleo-glacial reconstruction of the Thajwas glacier in the Kashmir Himalaya using 10Be cosmogenic radionuclide dating

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Geoscience Frontiers 2022年第6期13卷 30-40页

作者： Omar Jaan Paul shakil Ahmad Romshoo Reyaz Ahmad Dar Pankaj Kumar Soumya Prakash Dhal Sundeep Chopra Department of Earth Sciences University of KashmirSrinagarIndia Islamic University of Science and Technology(IUST) KashmirIndia Inter-University Accelerator Centre(IUAC) New DelhiIndia Department of Geoinformatics University of KashmirSrinagarIndia

Quantitative glacial chronologies of past glaciations are sparse in the Himalaya, and mostly absent in the Kashmir Himalaya. We used cosmogenicBe exposure dating, and geomorphological mapping to reconstruct glacial advances of the Thajwas Glacier(TG) in the Great Himalayan Range of the Kashmir Himalaya. FromBe exposure dating of ten moraine boulders, four glacial stages with ages ~20.77 ±2.28 ka, ~11.46 ± 1.69 ka, ~9.12 ± 1.39 ka and ~4.19 ± 0.78 ka, were identified. The reconstructed cosmogenic radionuclide ages confirmed the global Last Glacial maximum(g LGm), Younger Dryas, Early Holocene, and Neoglaciation episodes. As per area and volume change analyses, the TG has lost 51.1 km~2 of its area and a volume of 2.64 km~3 during the last 20.77 ± 2.28 ka. Overall, the results suggested that the TG has lost 64% of area and 73% of volume from the Last glacial maximum to Neoglaciation and about 85.74% and 87.67% of area and volume, respectively, from Neoglaciation to the present day. The equilibrium line altitude of the TG fluctuated from 4238 m a.s.l present to3365 m a.s.l during the g LGm(20.77 ± 2.28 ka). The significant cooling induced by a drop in mean ambient temperature resulted in a positive mass balance of the TG during the g LGm. Subsequently the melting accelerated due to the continuing rise of the global ambient temperature. Paleo-glacial history reconstruction of the Kashmir Himalaya, with its specific geomorphic and climatic setting, would help close the information gap about the chronology of past regional glacial episodes.

关键词： Glacier reconstruction Cosmogenic 10Be gLGm Kashmir Himalaya Equilibrium Line Altitude

The Effect of Injection Angle on mixing and Flame Holding in Supersonic Combustor

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Journal of Thermal Science 2002年第1期11卷 80-91页

作者： shakil Ahmed mohammad Ali A. K. m. Sadrul Islam Department of mechanical Engineering Bangladesh University of Engineering and Technology (BUET) Dhaka Bangladesh

A numerical study on mixing of hydrogen injected into a supersonic air stream has been performed by solving two-dimensional full Navier-Stokes equations. An explicit Harten-Yee Non-mUSCL modified-flux-type TVD scheme has been used to solve the system of equations, and a zero-equation algebraic turbulence model to calculate the eddy viscosity coefficient. The main objectives of this study are to increase the mixing efficiency and flame holding capability of a supersonic combustor. The performance of combustor has been investigated by varying the hydrogen injection angle made with the direction of air stream considering anti-clockwise direction as positive. The injector position from left boundary, backward-facing step height and the inlet width of air stream are kept constant. The results show that upstream of injector the mixing is dominated by recirculation and in downstream the mixing is dominated by mass concentration of hydrogen. Upstream recirculation is dominant for injecting angle 600 and 900 . Incorporating the various effects, perpendicular injection shows the maximum mixing efficiency and its large upstream recirculation region has a good flame holding capability.

关键词： scramjet engine TVD scheme backward-facing step supersonic mixing supersonic stream flame holding.

Spatio-temporal variation of land surface temperature and temperature lapse rate over mountainous Kashmir Himalaya

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Journal of mountain Science 2018年第3期15卷 563-576页

作者： shakil Ahmad ROmSHOO mohammd RAFIQ Irfan RASHID Department of Earth Sciences University of Kashmir

In this study, Land Surface Temperature(LST) and its lapse rate over the mountainous Kashmir Himalaya was estimated using mODIS data and correlated with the observed in-situ air temperature(Tair) data. Comparison between the mODIS LST and Tair showed a close agreement with the maximum error of the estimate ±1°C and the correlation coefficient >0.90. Analysis of the LST data from 2002-2012 showed an increasing trend at all the selected locations except at a site located in the southeastern part of Kashmir valley. Using the GTOPO30 DEm, mODIS LST data was used to estimate the actual temperature lapse rate(ATLR) along various transects across Kashmir Himalaya, which showed significant variations in space and time ranging from 0.3°C to 1.2°C per 100 m altitude change. This observation is at variance with the standard temperature lapse rate(STLR) of 0.65°C used universally in most of the hydrological and other land surface models. Snowmelt Runoff model(SRm) was used to determine the efficacy of using the ATLR for simulating the stream flows in one of the glaciated and snow-covered watersheds in Kashmir. The use of ATLR in the SRm model improved the R2 between the observed and predicted streamflows from 0.92 to *** is hoped that the operational use of satellite-derived LST and ATLR shall improve the understanding and quantification of various processes related to climate, hydrology and ecosystem in the mountainous and data-scarce Himalaya where the use of temperature and ATLR are critical parameters for understanding various land surface and climate processes.

关键词：陆地表面温度克什米尔时间显示差错率空间 mODIS 表面模型 LST

morphotectonic and Lithostratigraphic Analysis of Intermontane Karewa Basin of Kashmir Himalayas,India

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Journal of mountain Science 2013年第1期10卷 1-15页

作者： Reyaz Ahmad DAR Rakesh CHANDRA shakil Ahmad ROmSHOO Department of Earth Sciences The University of Kashmir

morpho-tectonic study plays an important role in deciphering the effects of tectonic activity in the geomorphic evolution of the drainage *** watershed forms one of the major watersheds of the intermontane Karewa Basin of Kashmir *** Karewa sediments are characterized by glacio-fluvio-lacustrine deposits capped by the aeolian *** geomorphic,morphometric and lithostratigraphic studies of these cap deposits have been carried out to elucidate the effect of tectonics on the geomorphic evolution of Romushi *** mapping was carried out using GPS measurements,DEm at 30m resolution,Topographic Position Index(TPI) model,topographic maps,LANDSAT Tm Imagery and field *** and morphotectonic analyses in GIS environment were used to calculate various geomorphic indices(mountain Front Sinuosity Index,Bifurcation Ratio,Asymmetry Factor,River Profile,etc).These indices reveal that the tectonic uplift observed in the region due to Himalayan orogeny coupled with mass movement and aeolian deposition have dominated the landscape evolution of intermontane Karewa Basin of Kashmir throughout the Late Quaternary *** data from lithostratigraphic measurements were analyzed to understand the geomorphic evolution of intermontane Karewa *** data revealed that the basin has experienced differential uplift and erosion rates from time to time in the geological *** was corroborated by the results from the morphometric and morphotectonic analysis.

关键词：喜马拉雅山脉地貌演化山间盆地克什米尔地层分析卡尔数字高程模型岩石

modelling Chorabari Lake outburst flood, Kedarnath, India

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Journal of mountain Science 2019年第1期16卷 64-76页

作者： mohammd RAFIQ shakil Ahmad ROmSHOO Anoop Kumar mISHRA Faizan JALAL Centre for Remote Sensing and Geoinformatics Sathyabama Institute of Science and Technology Department of Earth Sciences University of Kashmir

In this study, the Glacier Lake Outburst Flood(GLOF) that occurred over Kedarnath in June 2013 was modeled using integrated observations from the field and Remote Sensing(RS). The lake breach parameters such as area, depth, breach, and height have been estimated from the field observations and Remote Sensing(RS) data. A number of modelling approaches, including Snow melt Runoff model(SRm), modified Single Flow model(mSF), Watershed management System(WmS), Simplified Dam Breach model(SmPDBK) and BREACH were used to model the GLOF. Estimations from SRm produced a runoff of about 22.7 m3 during 16–17, June 2013 over Chorabari Lake. Bathymetry data reported that the lake got filled to its maximum capacity(3822.7 m3) due to excess discharge. Hydrograph obtained from the BREACH model revealed a peak discharge of about 1699 m3/s during an intense water flow episode that lasted for 10–15 minutes on 17 th June 2013. Excess discharge from heavy rainfall and snowmelt into the lake increased its hydrostatic pressure and the lake breached cataclysmically.

关键词： Glacier lake outburst flood GIS modelling Snow melt Runoff Kedarnath Glacier Lake