Aerosol-trace gases interactions and their role in air quality control of Delhi city (India)     

Anshu Sharma  Saumya Singh  Umesh C. Kulshrestha 《Arabian Journal of Geosciences》2018,11(13):358

Atmospheric dust is considered to be the major cause of poor air quality due to its contribution to high particulate levels, but their interaction with the acidic gases helps in controlling the level of SO₂ and NO₂ through ambient neutralization reactions. In the present study, the interaction of acidic gases such as SO₂ and NO₂ with alkaline dust was investigated during October, 2013–July, 2014 at a site named as Babarpur located at the Trans-Yamuna region of Delhi. The concentration of SO₂ ranged from 10 to 170 μg/m³ with an average of 36 μg/m³ while that of NO₂ ranged from 15 to 54 μg/m³ with an average of 26?±?8 μg/m³. The results were observed to be well within the National Ambient Air Quality Standard (NAAQS) limits prescribed by the Central Pollution Control Board (CPCB). The average concentrations of SO₂ during day and night time were recorded as 31?±?18 and 43?±?53 μg/m³ respectively while the mean concentrations of NO₂ during day and night time were recorded as 26?±?7 and 27?±?12 μg/m³ respectively. A positive correlation between SO₄^2? and NO₃^? was also observed indicating their secondary aerosol formation. In aerosol phase, average concentrations of SO₄^2? during day and night time were 3.9?±?0.3 and 6.5?±?2.3 μg/m³ respectively while that of NO₃^? were 9.5?±?1.5 and 7.3?±?0.5 μg/m³ respectively. Molar ratios of Ca²⁺/SO₄^2?, NH₄⁺/SO₄^2?, and NH₄⁺/NO₃^? were observed as 8, 5, and 1.7 during daytime and 1.5, 0.4, and 0.8 during nighttime respectively. Such molar ratios confirmed high concentrations of sulphate (SO₄)^2? and low concentrations of nitrate (NO₃^?) during night time, thereby indicating different pathway of aerosol formation during day and night time. Surface morphology and elemental composition of aerosol samples showed various oval, globular, and platy shapes where the diameter varied from few nm to ~5 μm depending on their precursors. There were certain shapes like grossularite, irregular aggregate, grape-like, triangular, and flattened which indicate the crustal origin of aerosols and their possible role in SO₂ and NO₂ adsorption.  相似文献   

Holocene tectono-geomorphic evolution of Haryana plains,Western Ganga plain,India     

Pitambar Pati  Vivekanand Acharya  Aditya Kumar Verma  Narendra Kumar Patel  Rajendra Prasad Jakhmola  Chinmay Dash  Vijay Sharma  Ankit Gupta  Brahm Parkash  Arun Kumar Awasthi 《Arabian Journal of Geosciences》2018,11(13):361

Haryana plain is the drainage divide between the Ganga plain in the east and the Indus plain in the west. Being a part of the Himalayan foreland, its geomorphology, sedimentation processes, and tectonism are broadly controlled by the Himalayan tectonics. Soil and geomorphological mapping in Haryana plain bring out geomorphic features such as paleochannels, various active drainage patterns, and landforms such as old fluvial plains, floodplains, piedmonts, pediments, terminal fans, and eolian plains. Based on the degree of soil development, and Optical stimulated luminescence (OSL) ages, the soil-geomorphic units were grouped into six members (QIMS-I to VI) (Quaternary Indus Morphostratigraphic Sequence) of a morphostratigraphic sequence: QIMS-VI 9.86–5.38 Ka, QIMS-V 5.38–4.45 Ka, QIMS-IV 4.45–3.60 Ka, QIMS-III 3.60–2.91 Ka, QIMS-II <?2.91–1.52 Ka, and QIMS-I <?1.52 Ka. OSL chronology of different geomorphic features suggests six episodes of tectono-geomorphic evolution in the region since 10 Ka. Neotectonic features such as nine faults, two lineaments, and five fault-bounded tectonic blocks have been identified. Independent tilting and sagging of the blocks in response to neotectonics have resulted in modification of landforms, depositional processes, and hydro-geomorphology of the region. Major rivers like the Yamuna, the Ghaggar, and the Sutlej show different episodes of shifting of their courses. Lineament controlled few extinct channels have been recorded between 20 and 25 m depth below the surface in the ground-penetrating radar (GPR) profiles. These buried channels are aligned along the paleo-course of the Lost Saraswati River interpreted from the existing literature and hence are considered as the course of the lost river. Seven terminal fans have been formed on the downthrown blocks of the associated faults. The Markanda Terminal Fan, the first of such features described, is indeed a splay terminal fan and was formed by a splay distributary system of the Markanda River. Association of three terminal fans of different ages with the Karnal fault indicates the segment-wise development of the fault from west to east. Also, comparison with other such studies in the Ganga plain to further east suggests that the terminal fans formed by streams with distributary drainage pattern occur only in semiarid regions as in the present area and thus are indicators of semiarid climate/paleoclimate. Though the whole region is tectonically active, the region between the Rohtak fault and Hisar fault is most active at present signified by the concentration of earthquake epicenters.  相似文献   

Vegetation damage assessment due to Hudhud cyclone based on NDVI using Landsat-8 satellite imagery     

Venkata Giri Raj Kumar Konda  Venkatesh Reddy Chejarla  Venkata Ravibabu Mandla  Vani Voleti  Nagaveni Chokkavarapu 《Arabian Journal of Geosciences》2018,11(2):35

Developing nations are abandoned against tropical cyclones because of climatic changeability; the atmosphere is probably going to expand the recurrence and extent of some outrageous climate and calamity occasions. Urban areas and towns arranged along the coastline front belt in Visakhapatnam region experienced serious harm because of Hudhud cyclone, which happened on October 12, 2014. The fundamental motivation behind this exploration was to distinguish the vegetation damage in Visakhapatnam and neighbouring towns. In this analysis, Landsat-8 satellite datasets procured prior and then afterward the cyclone have been utilized; image processing techniques have been completed to evaluate the progressions of pre- and post-disaster condition. Vegetation index strategy was utilized to assess the damage to vegetation. Arrangement results and land utilize land cover change investigation demonstrate that 13.25% of agriculture Kharif and 31.1% of vegetation was damaged. Normalized difference vegetation index (NDVI) maps were produced for the previously, then after the cyclone circumstance, and vegetation biomass damage was evaluated in Visakhapatnam and Bhimunipatanam. General loss of vegetation in both the spots was 30.67 and 43.37 km². The result of this review can be utilized by decision makers for the post-disaster support for rebuilding of influenced regions.  相似文献   

Construction and Characterization of Transportable Calibration Pads for Calibration of Portable and Airborne Gamma Ray Spectrometers in India     

Pravin Kumar Sharma  Nalin Kumar Johri  Gagan Behari Raut  G. Rangaswamy  Brahma Kishore Pandey  Anand Kumar Chaturvedi 《Journal of the Geological Society of India》2018,91(3):281-289

Characterization of the Panandhro lignite deposits from western Indian state of Gujarat, based on the geochemical and palynological evidences, has been performed to assess the floral composition, maturity and hydrocarbon potential of the sequence. Elementally, the lignites consist of moderate carbon, low hydrogen and moderate sulfur contents. The samples are characterized by high TOC contents (lignite: av. 46.43 wt.%, resin: 62.47 wt.%). The average HI values for the lignite is 136 mg HC/g TOC, and that of the associated resin is 671 mg HC/g TOC. The highest T_max is recoded in lignite (422°C) and lowest in the resin (39°C) samples. The FTIR spectrum of lignite is characterized by highly intense OH stretching peak ~3350 cm^-1, aliphatic CH_x stretching peaks between 3000-2800 cm^-1, aromatic C=O stretching and an aromatic C=C stretching. The spectrum of resin shows strongest absorption due to aliphatic CHx stretching between 2940-2915 cm^-1 and 2870-2850 cm^-1, and deformation by the medium peak between 1450 and 1650 cm^-1. The recovered palynofloral assemblage indicates the dominance of angiosperm pollen grains with maximum abundance of Arecaceae family, and subdominant pteridophytic spores. Marine influence is indicated by the presence of abundant dinoflagellate cysts. The occurrence of flora from a variety of ecological niches suggests a luxuriant diverse vegetation pattern existed in the vicinity of depositional site under humid tropical conditions. The overall characteristics of the lignite deposits point towards their ability to generate (upon maturation) hydrocarbons as they have types III–II admixed kerogen (organic matters).  相似文献   

Calibration of AGRS System Using Transportable Pads in India: An Application to AGRS Data of Aravalli Basin,Banswada Block,South Rajasthan     

M. S. Ramayya  A. K. Chaturvedi  P. S. Parihar  P. K. Sharma  D. U. Jiwane  P. K. Srivastava  T. C. Sunil 《Journal of the Geological Society of India》2018,91(5):535-540

Calibration of airborne gamma ray spectrometric system (AGRS) over standard radioactive sources of known elemental abundances is essential before carrying out airborne surveys. In India, fixed calibration pads were constructed in 1985. Since then calibration of AGRS system was carried out over the fixed pads. However the fixed pads are expensive to build and maintain. Also the large pads are subject to variations in radiation output due to variable moisture content and radon loss. Alternate approach is to construct transportable calibration pads which are discussed in this paper.Atomic Minerals Directorate for Exploration & Research (AMD) under Department of Atomic Energy has recently constructed five transportable calibration pads. Three pads i.e. K, U and Th have been spiked with the respective radioelements while keeping the minor radioelements to the least in order to obtain pure spectra. A composite pad has been constructed which contains all the three radioelements. This helps in cross verifying the obtained calibration results. A background pad has also been constructed which is helpful to obtain the background values during calibration.Analysis of the data acquired over the transportable pads with airborne gamma ray spectrometer (16.8 ltr) has been carried out and presented in this paper. A comparison with the data acquired over the fixed calibration pads is also included. There is a good agreement of results which suggests the use of transportable pads in future.  相似文献   

Design principles for origin-destination flow maps     

Bernhard Jenny  Daniel M. Stephen  Ian Muehlenhaus  Brooke E. Marston  Ritesh Sharma  Eugene Zhang 《制图学和地理信息科学》2018,45(1):62-75

Origin-destination flow maps are often difficult to read due to overlapping flows. Cartographers have developed design principles in manual cartography for origin-destination flow maps to reduce overlaps and increase readability. These design principles are identified and documented using a quantitative content analysis of 97 geographic origin-destination flow maps without branching or merging flows. The effectiveness of selected design principles is verified in a user study with 215 participants. Findings show that (a) curved flows are more effective than straight flows, (b) arrows indicate direction more effectively than tapered line widths, and (c) flows between nodes are more effective than flows between areas. These findings, combined with results from user studies in graph drawing, conclude that effective and efficient origin-destination flow maps should be designed according to the following design principles: overlaps between flows are minimized; symmetric flows are preferred to asymmetric flows; longer flows are curved more than shorter or peripheral flows; acute angles between crossing flows are avoided; sharp bends in flow lines are avoided; flows do not pass under unconnected nodes; flows are radially distributed around nodes; flow direction is indicated with arrowheads; and flow width is scaled with represented quantity.  相似文献   

Transforming local natural resource conflicts to cooperation in a changing climate: Bangladesh and Nepal lessons     

Parvin Sultana  Paul Michael Thompson  Naya Sharma Paudel  Madan Pariyar  Mujibur Rahman 《Climate Policy》2019,19(6):S94-S106

ABSTRACT

Since the 1990s, climate change impact discourse has highlighted potential for large scale violent conflicts. However, the role of climate stresses on local conflicts over natural resources, the role of policies and adaptation in these conflicts, and opportunities to enhance cooperation have been neglected. These gaps are addressed in this paper using evidence from participatory action research on 79 cases of local collective action over natural resources that experience conflicts in Bangladesh and Nepal. Climate trends and stresses contributed to just under half of these conflict cases. Nine factors that enable greater cooperation and transformation of conflict are identified. Participatory dialogue and negotiation processes, while not sufficient, changed understanding, attitudes and positions of actors. Many of the communities innovated physical measures to overcome natural resource constraints, underlying conflict, and/or institutional reforms. These changes were informed by improving understanding of resource limitations and indigenous knowledge. Learning networks among community organizations encouraged collective action by sharing successes and creating peer pressure. Incentives for cooperation were important. For example, when community organizations formally permitted excluded traditional resource users to access resources, those actors complied with rules and paid towards management costs. However, elites were able to use policy gaps to capture resources with changed characteristics due to climate change. In most of the cases where conflict persisted, power, policy and institutional barriers prevented community-based organizations from taking up potential adaptations and innovations. Policy frameworks recognizing collective action and supporting flexible innovation in governance and adaptation would enable wider transformation of natural resource conflicts into cooperation.

Key policy insights

• Climate stresses, policy gaps and interventions can all worsen local natural resource conflicts.

• Sectoral knowledge and technical approaches to adaptation are open to elite capture and can foster conflicts.

• Many local natural resource conflicts can be resolved but this requires an enabling environment for participatory dialogue, external facilitation, flexible responses to context, and recognition of disadvantaged stakeholder interests.

• Transforming conflict to greater cooperation mostly involves social and institutional changes, so adaptation policies should focus less on physical works and more on enabling factors such as negotiation, local institutions, knowledge, and incentives.

  相似文献   

Dissociation constants of protonated cysteine species in seawater media     

Virender K. Sharma  Aurelie Moulin  Frank J. Millero  Concetta De Stefano 《Marine Chemistry》2006,99(1-4):52

The dissociation constants (pK₁, pK₂ and pK₃) for cysteine have been measured in seawater as a function of temperature (5 to 45 °C) and salinity (S = 5 to 35). The seawater values were lower than the values in NaCl at the same ionic strength. In an attempt to understand these differences, we have made measurements of the constants in Na–Mg–Cl solutions at 25 °C. The measured values have been compared to those calculated from the Pitzer ionic interaction model. The lower values of pK₃ in the Na–Mg–Cl solutions have been attributed to the formation of Mg²⁺ complexes with Cys²⁻ anionsThe stability constants have been fitted toafter corrections are made for the interaction of Mg²⁺ with H⁺.The pK₁ seawater measurements indicate that H₃Cys⁺ interacts with SO₄²⁻. The Pitzer parameters β⁰(H₃CysSO₄), β¹(H₃CysSO₄) and C(H₃CysSO₄) have been determined for this interaction. The formation of CaCys as well as MgCys are needed to account for the values of pK₂ and pK₃ in seawater.The consideration of the formation of MgCys and CaCys in seawater yields model calculated values of pK₁, pK₂ and pK₃ that agree with the measured values to within the experimental error of the measurements. This study shows that it is important to consider all of the ionic interactions in natural waters when examining the dissociation of organic acids.  相似文献   

Swelter in the city: Urban greenery and its effects on temperature in Guwahati,India     

Monjit Borthakur  Anup Saikia  Kiran Sharma 《Singapore journal of tropical geography》2020,41(3):341-366

Changing urban landscape with multistoried high rises, roads and pavements is continuously reducing urban green space. These structures result in high surface temperature variation within cities. To explore the relationship between surface temperature and normalized difference vegetation index (NDVI), this study estimates two models—geographically weighted regression (GWR) and a fixed effect panel data model in relation to the Guwahati Metropolitan Area (GMA), a secondary city in north east India. The results indicate the superiority of GWR regression in presence of spatial dependence. Panel data analysis shows that the densely populated urban areas in the GMA with less than 10 per cent greenery are 1°C warmer than the sub-urban areas with 50 per cent greenery.  相似文献   

喜马拉雅中部甘达基河流域尼泊尔国鸟(棕尾虹雉)生境分布变化     

Raju RAI  Basanta PAUDEL  谷昌军  Narendra Raj KHANAL 《资源与生态学报(英文版)》2020,11(2):223-231

甘达基河流域(Gandaki River Basin,GRB)是喜马拉雅中部地区的一部分,该地区栖息着许多珍稀的野生动物。由于气候和人类活动的影响,许多珍稀保护物种的生境处于危险之中。本研究基于最大熵(MaxEnt)模型,运用生物气候、土地覆被和DEM数据,分析各环境要素对棕尾虹雉(Lophophorusimpejanus)的生境适宜性的影响,评估棕尾虹雉现在状况和未来栖息地分布的变化。研究表明,目前棕尾虹雉的高度适宜栖息地面积约为749 km^2,主要分布在流域北部、东部和西部,尤其是郎塘国家公园、马纳斯卢峰自然保护区和安纳布尔纳峰自然保护区等保护区内。到2050年,棕尾虹雉的高度适宜栖息地面积将减少至561 km^2,主要在流域北部和西北部(即Chhyo,Tatopani,Humde和Chame地区)。未来环境变化的模拟表明,由于适宜栖息地面积的减少,棕尾虹雉面临的生存风险将增加。  相似文献