|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Using Landsat images to monitor changes in the snow-covered area of selected glaciers in northern Pakistan显示文摘Landsat satellite images were used to map and monitor the snow-covered areas of four glaciers with different aspects(Passu: 36.473°N, 74.766°E;Momhil: 36.394°N, 75.085°E; Trivor: 36.249°N,74.968°E; and Kunyang: 36.083°N, 75.288°E) in the upper Indus basin, northern Pakistan, from 1990-2014. The snow-covered areas of the selected glaciers were identified and classified using supervised and rule-based image analysis techniques in three different seasons. Accuracy assessment of the classified images indicated that the supervised classification technique performed slightly better than the rule-based technique. Snow-covered areas on the selected glaciers were generally reduced during the study period but at different rates. Glaciers reached maximum areal snow coverage in winter and premonsoon seasons and minimum areal snow coverage in monsoon seasons, with the lowest snow-covered area occurring in August and September. The snowcovered area on Passu glacier decreased by 24.50%,3.15% and 11.25% in the pre-monsoon, monsoon and post-monsoon seasons, respectively. Similarly, the other three glaciers showed notable decreases in snow-covered area during the pre-and post-monsoon seasons; however, no clear changes were observed during monsoon seasons. During pre-monsoon seasons, the eastward-facing glacier lost comparatively more snow-covered area than the westward-facing glacier. The average seasonal glacier surface temperature calculated from the Landsat thermal band showed negative correlations of-0.67,-0.89,-0.75 and-0.77 with the average seasonal snowcovered areas of the Passu, Momhil, Trivor and Kunyang glaciers, respectively, during pre-monsoon seasons. Similarly, the air temperature collected from a nearby meteorological station showed an increasing trend, indicating that the snow-covered area reduction in the region was largely due to climate warming. | Chaman GUL KANG Shi-chang Badar GHAURI Mateeul HAQ Sher MUHAMMAD Shaukat ALI | 2017 | Journal of Mountain Science2017，14，10： | 4 |
| 2 | Seasonality of carbonaceous aerosol composition and light absorption properties in Karachi,Pakistan显示文摘Characteristics of carbonaceous aerosol(CA)and its light absorption properties are limited in Karachi,which is one of the most polluted metropolitan cities in South Asia.This study presents a comprehensive measurement of seasonality of CA compositions and mass absorption cross-section(MAC)of elemental carbon(EC)and water-soluble organic carbon(WSOC)in total suspended particles(TSP)collected from February 2015 to March 2017 in the southwest part of Karachi.The average TSP,organic carbon(OC),and EC concentrations were extremely high with values as 391.0±217.0,37.2±28.0,and 8.53±6.97μg/m3,respectively.These components showed clear seasonal variations with high concentrations occurring during fall and winter followed by spring and summer.SO42-,NO3-,K+,and NH4+showed similar variations with CA,implying the significant influence on atmospheric pollutants from anthropogenic activities.Relatively lower OC/EG ratio(4.20±2.50)compared with remote regions further indicates fossil fuel combustion as a primary source of CA.Meanwhile,sea salt and soil dust are important contribution sources for TSP.The average MAC of EC(632 nm)and WSOC(365 nm)were 6.56±2.70 and 0.97±0.37 m2/g,respectively.MACEC is comparable to that in urban areas but lower than that in remote regions,indicating the significant influence of local emissions.MACwsoc showed opposite distribution with EC,further suggesting that OC was significantly affected by local fossil fuel combustion.In addition,dust might be an important factor increasing MACwsoc particularly during spring and summer. | Pengfei Chen Shichang Kang Chaman Gul Lekhendra Tripathee Xiaoxiang Wang Zhaofu Hu Chaoliu Li Tao Pu | 2020 | Journal of Environmental Sciences2020，32，4： | 3 |
| 3 | Atmospheric particle-bound polycyclic aromatic compounds over two distinct sites in Pakistan:Characteristics,sources and health risk assessment显示文摘Much attention is drawn to polycyclic aromatic hydrocarbons(PAHs)as an air pollutant due to their toxic,mutagenic and carcinogenic properties.Therefore,to understand the levels,seasonality,sources and potential health risk of PAHs in two distinct geographical locations at Karachi and Mardan in Pakistan,total suspended particle(TSP)samples were collected for over one year period.The average total PAH concentrations were 31.5±24.4 and 199±229 ng/m^(3) in Karachi and Mardan,respectively.The significantly lower concentration in Karachi was attributed to diffusion and dilution of the PAHs by the influence of clean air mass from the Arabian sea and high temperature,enhancing the volatilization of the particle phase PAHs to the gas phase.Conversely,the higher concentration(^(-)6 times)in Mardan was due to large influence from local and regional emission sources.A clear seasonality was observed at both the sites,with the higher values in winter and post-monsoon due to higher emissions and less scavenging,and lower values during monsoon season due to the dilution effect.Diagnostic ratios and principal component analysis indicated that PAHs in both sites originated from traffic and mixed combustion sources(fossil fuels and biomass).The average total Ba P equivalent concentrations(Ba P eq)in Karachi and Mardan were 3.26 and 34 ng/m^(3),respectively,which were much higher than the WHO guideline of 1 ng/m^(3).The average estimates of incremental lifetime cancer risk from exposure to airborne Ba P eq via inhalation indicated a risk to human health from atmospheric PAHs at both sites. | Linda Maharjan Shichang Kang Lekhendra Tripathee Chaman Gul Huijun Zheng Quanlian Li Pengfei Chen Mukesh Rai Ewerton Santos | 2022 | Journal of Environmental Sciences2022，34，2： | 2 |
| 4 | Identification and characterization of two novel antimicrobial peptides,temporin-Ra and temporin-Rb,from skin secretions of the marsh frog (Rana ridibunda)显示文摘 | Asoodeh A Zardinia H Z Chamanic J K | | 0，，1： | 1 |
| 5 | Structural, optical and transport properties of Al 3+ doped BiFeO 3 nanopowder synthesized by solution combustion method显示文摘 | Ameer Azam Ali Jawad Arham S. Ahmed M. Chaman A.H. Naqvi | 2010 | Journal of Alloys and Compounds2010，，6： | 1 |
| 6 | How re- sponsive is Chinese export supply to market signals? 显示文摘 | Cerra Valerie Saxena Sweta Chaman | 2003 | China Economic Review2003，14，3： | 1 |
| 7 | Ethylene production and peroxidase activity in aphid- infested barley 显示文摘 | Argandona V H Chaman M Cardemil L el al | 2001 | Journal of Chemical Ecology2001，27，1： | 1 |
| 8 | Ethylene production and peroxidase activity in aphid-infested barley显示文摘 | Argandona V H Chaman M Cardemil L | 2001 | Journal of Chemical E-cology2001，27，1： | 1 |
| 9 | Preservative tolerance and resistance显示文摘 | Chaman J S Diehl M A Fearnside K B | 1998 | International Journal of Cosmetic Science1998，20，1： | 1 |
| 10 | Ethylene production and peroxidase activity in aphid-infested barley 显示文摘 | ARGANDONA V H CHAMAN M CARDEMIL L | 2001 | Journal of Chemical Ecology2001，27，1： | 1 |
| 11 | Nitric oxide in the cardiovascular system: a simple molecule with complex ac- tions显示文摘 | Strijdom H Chamane N Lochner A | 2009 | Cardiovasc J Afr2009，20，5： | 1 |
| 12 | A novel antioxidant and antimicrobial peptide from hen egg white lysozyme hydrolysates显示文摘 | YAZDI M M ASOODEH A CHAMAN J | 2012 | Journal of Functional Foods2012，4，1： | 1 |
| 13 | Ethylene production and peroxidase activity in aphid infested barley显示文摘 | Argandona V H Chaman M Cardemil L | 2001 | Journal of Chemical Ecology2001，27，： | 1 |
| 14 | Objective technique for the determination of monochromatic aberrations of the human eye显示文摘 | Walsh G Chaman W N Howland H | 1984 | J Opt Soc Am A1984，1，9： | 1 |
| 15 | Autoantibedies can be prognostic markers of an erosive disease in ERA显示文摘 | Kamal solanki Myfanwy spellers Peter chaman | 2004 | N Engl J Med2004，117，： | 1 |
| 16 | Morphogenesis of occluding coronary artery thrombosis显示文摘 | Chaman I | 1965 | Arch Pathol LabMed1965，80，： | 1 |
| 17 | Contagion,Monsoons, and Domestic Turmoil in Id o n e -sia' Currency Crisis显示文摘 | Cerra Valerie Sweta Chaman Saxena | 2002 | Review of International Economics2002，10，1： | 1 |
| 18 | Hyperhomocysteinemia,folateo and B12 vitamin in Iranian patients with acute i schemic stroke显示文摘 | OMRANI HQ SHANDIZ EE QABAI M CHAMAN R | | 0，，03： | 1 |
| 19 | Nitric oxide in the car-diovascular system:a simple molecule with complex actions显示文摘 | StrijdomH Chamane N LochnerA | 2009 | Cardiovasc JAfr2009，20，5： | 1 |
| 20 | Breastfeeding practices during the first month postpartum and associated factors: impact on breastfeeding survival显示文摘 | Mortazavi F Mousavi S A Chaman R | 2015 | Iran Red Cres- cent Med J2015，17，27： | 1 |
您所在的机构暂未开通此部分的功能，请联系管理员