| 1. |
- Bikkina, Srinivas, et al.
(författare)
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Air quality in megacity Delhi affected by countryside biomass burning
- 2019
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Ingår i: Nature Sustainability. - : Springer Science and Business Media LLC. - 2398-9629. ; 2:3, s. 200-205
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Tidskriftsartikel (refereegranskat)abstract
- South Asian megacities are strong sources of regional air pollution. Delhi is a key hotspot of health-and climate-impacting black carbon (BC) emissions, affecting environmental sustainability in densely populated northern India. Effective mitigation of BC impact is hampered by highly uncertain emission source estimates. Here, we use dual-carbon isotope fingerprints (delta C-13/Delta C-14) of BC to constrain the seasonal source variability in Delhi. These measurements show that lower BC concentrations in summer are predominantly from fossil fuel sources (similar to 83%). However, large-scale open burning of post-harvest crop residue/wood in nearby rural regions is contributing to severe haze pollution in Delhi during winter and autumn (similar to 42 +/- 17%). Hence, the common conception that megacities affect their surroundings is here amended or seasonally reversed. Therefore, to combat the severe air pollution problems in Delhi and the environmental quality of northern India, current urban efforts need to be complemented with countryside regional mitigation.
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| 2. |
- Bosch, Carme, et al.
(författare)
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Source-diagnostic dual-isotope composition and optical properties of water-soluble organic carbon and elemental carbon in the South Asian outflow intercepted over the Indian Ocean
- 2014
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Ingår i: Journal of Geophysical Research - Atmospheres. - 2169-897X .- 2169-8996. ; 119:20, s. 11743-11759
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Tidskriftsartikel (refereegranskat)abstract
- The dual carbon isotope signatures and optical properties of carbonaceous aerosols have been investigated simultaneously for the first time in the South Asian outflow during an intensive campaign at the Maldives Climate Observatory on Hanimaadhoo (MCOH) (February and March 2012). As one component of the Cloud Aerosol Radiative Forcing Dynamics Experiment, this paper reports on the sources and the atmospheric processing of elemental carbon (EC) and water-soluble organic carbon (WSOC) as examined by a dual carbon isotope approach. The radiocarbon (C-14) data show that WSOC has a significantly higher biomass/biogenic contribution (865%) compared to EC (594%). The more C-13-enriched signature of MCOH-WSOC (-20.80.7) compared to MCOH-EC (-25.8 +/- 0.3 parts per thousand) and megacity Delhi WSOC (-24.1 +/- 0.9 parts per thousand) suggests that WSOC is significantly more affected by aging during long-range transport than EC. The C-13-C-14 signal suggests that the wintertime WSOC intercepted over the Indian Ocean largely represents aged primary biomass burning aerosols. Since light-absorbing organic carbon aerosols (Brown Carbon (BrC)) have recently been identified as potential contributors to positive radiative forcing, optical properties of WSOC were also investigated. The mass absorption cross section of WSOC (MAC(365)) was 0.5 +/- 0.2 m(2)g(-1) which is lower than what has been observed at near-source sites, indicating a net decrease of WSOC light-absorption character during long-range transport. Near-surface WSOC at MCOH accounted for similar to 1% of the total direct solar absorbance relative to EC, which is lower than the BrC absorption inferred from solar spectral observations of ambient aerosols, suggesting that a significant portion of BrC might be included in the water-insoluble portion of organic aerosols.
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| 3. |
- Chavhan, Suresh, et al.
(författare)
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Edge-enabled Blockchain-based V2X Scheme for Secure Communication within the Smart City Development
- 2023
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Ingår i: IEEE Internet of Things Journal. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 2327-4662. ; 10:24, s. 21282-21293
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Tidskriftsartikel (refereegranskat)abstract
- As the high mobility nature of the vehicles results in frequent leaving and joining the transportation network, real-time data must be collected and shared in a timely manner. In such a transportation network, malicious vehicles can disrupt services and create serious issues, such as deadlocks and accidents. The blockchain is a technology that ensures traceability, consistency, and security in transportation networks. In this study, we integrated edge computing and blockchain technology to improve the optimal utilization of resources, especially in terms of computing, communication, security, and storage. We propose a novel, edge-integrated, blockchain-based vehicle platoon security scheme. For the vehicle platoon, we developed the security architecture, implemented smart contracts for practical network scenarios in NS-3, and integrated them with the SUMO TraCI API. We exhaustively simulated all the scenarios and analyzed the communication performance metrics, such as throughput, delay, and jitter, and the security performance metrics, such as mean squared error, communication, and computational cost. The performance results demonstrate that the developed scheme can solve security-related issues more effectively and efficiently in smart cities. © IEEE
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| 4. |
- Dasari, Sanjeev, et al.
(författare)
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Photochemical degradation affects the light absorption of water-soluble brown carbon in the South Asian outflow
- 2019
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- Light-absorbing organic aerosols, known as brown carbon (BrC), counteract the overall cooling effect of aerosols on Earth's climate. The spatial and temporal dynamics of their light-absorbing properties are poorly constrained and unaccounted for in climate models, because of limited ambient observations. We combine carbon isotope forensics (delta C-13) with measurements of light absorption in a conceptual aging model to constrain the loss of light absorptivity (i.e., bleaching) of water-soluble BrC (WS-BrC) aerosols in one of the world's largest BrC emission regions-South Asia. On this regional scale, we find that atmospheric photochemical oxidation reduces the light absorption of WS-BrC by similar to 84% during transport over 6000 km in the Indo-Gangetic Plain, with an ambient first-order bleaching rate of 0.20 +/- 0.05 day(-1) during over-ocean transit across Bay of Bengal to an Indian Ocean receptor site. This study facilitates dynamic parameterization of WS-BrC absorption properties, thereby constraining BrC climate impact over South Asia.
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| 5. |
- Jannu, Srikanth, et al.
(författare)
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Energy Efficient Quantum-Informed Ant Colony Optimization Algorithms for Industrial Internet of Things
- 2024
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Ingår i: IEEE Transactions on Artificial Intelligence. - Piscataway : IEEE. - 2691-4581. ; 5:3, s. 1077-1086
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Tidskriftsartikel (refereegranskat)abstract
- One of the most prominent research areas in information technology is the Internet of things (IoT) as its applications are widely used such as structural monitoring, health care management systems, agriculture and battlefield management, and so on. Due to its self-organizing network and simple installation of the network, the researchers have been attracted to pursue research in the various fields of IoTs. However, a huge amount of work has been addressed on various problems confronted by IoT. The nodes densely deploy over critical environments and those are operated on tiny batteries. Moreover, the replacement of dead batteries in the nodes is almost impractical. Therefore, the problem of energy preservation and maximization of IoT networks has become the most prominent research area. However, numerous state-of-the-art algorithms have addressed this issue. Thus, it has become necessary to gather the information and send it to the base station in an optimized method to maximize the network. Therefore, we propose a novel quantum-informed ant colony optimization (ACO) routing algorithm with the efficient encoding scheme of cluster head selection and derivation of information heuristic factors. The algorithm has been tested by simulation for various network scenarios. The simulation results of the proposed algorithm show its efficacy over a few existing evolutionary algorithms using various performance metrics such as residual energy of the network, network lifetime, and the number of live IoT nodes. © 2022 IEEE
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| 6. |
- Kirillova, Elena N., et al.
(författare)
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Water-soluble organic carbon aerosols during a full New Delhi winter : Isotope-based source apportionment and optical properties
- 2014
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH - ATMOSPHERES. - 2169-8996. ; 119:6, s. 3476-3485
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Tidskriftsartikel (refereegranskat)abstract
- Water soluble organic carbon (WSOC) aerosol is a major constituent (~ 20-80% of the total organic carbon) of the ‘brown cloud’ that shades the Indian Subcontinent. Due to the multiple formation pathways (both primary and secondary), the emissions sources of WSOC are particularly poorly constrained. In this study, we present radiocarbon constraints on the biomass vs fossil sources of WSOC in PM2.5 for the 2010/11 winter period for the megacity Delhi, situated in the center of the heavily polluted Indo-Gangetic Plain. The fossil contribution (22±4%) to WSOC in Delhi is found to be similar to fossil fraction at Indian background sites. Stable carbon analysis shows that Delhi WSOC is more depleted in 13C relative to what is found at receptor sites, indicating that near-source WSOC is less affected by atmospheric aging. In addition, the light absorptive properties of WSOC were investigated. The mass absorption cross section at 365 nm (MAC365) ranged 1.1 – 2.7 m2/g, and the corresponding absorption Ångström exponent (AAE) ranged between 3.1 and 9.3. Using a simplistic estimate of the relative absorptive radiative forcing was found to be 6 – 42 % relative to that of black carbon. Taken together this near-source study emphasize the importance of taking into account the complex transformations of WSOC during air mass transport, as compared with regional receptor sites.
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| 7. |
- Parlak, Onur, et al.
(författare)
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Switchable Bioelectrocatalysis Controlled by Dual Stimuli-Responsive Polymeric Interface
- 2015
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 7:43, s. 23837-23847
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Tidskriftsartikel (refereegranskat)abstract
- The engineering of bionanointerfaces using stimuli-responsive polymers offers a new dimension in the design of novel bioelectronic interfaces. The integration of electrode surfaces with stimuli-responsive molecular cues provides a direct control and ability to switch and tune physical and chemical properties of bioelectronic interfaces in various biodevices. Here, we report a dual-responsive biointerface employing a positively responding dual-switchable polymer, poly(NIPAAm-co-DEAEMA)-b-HEAAm, to control and regulate enzyme-based bioelectrocatalysis. The design interface exhibits reversible activation deactivation of bioelectrocatalytic reactions in response to change in temperature and in pH, which allows manipulation of biomolecular interactions to produce on/off switchable conditions. Using electrochemical measurements, we demonstrate that interfacial bioelectrochemical properties can be tuned over a modest range of temperature (i.e., 20-60 degrees C) and pH (i.e., pH 4-8) of the medium. The resulting dual-switchable interface may have important implications not only for the design of responsive biocatalysis and on-demand operation of biosensors, but also as an aid to elucidating electron-transport pathways and mechanisms in living organisms by mimicking the dynamic properties of complex biological environments and processes.
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| 8. |
- Rao, P. S. P., et al.
(författare)
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Sources of chemical species in rainwater during monsoon and non-monsoonal periods over two mega cities in India and dominant source region of secondary aerosols
- 2016
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 146, s. 90-99
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Tidskriftsartikel (refereegranskat)abstract
- Samples of rainwater (RW) were collected to characterize the chemistry and sources in two representative megacities at Pune (Southwest) and Delhi (Northern) India from 2011 to 2014 across two seasons: monsoon (MN) and non-monsoon (NMN). Collected RW samples were analyzed for major chemical constituents (F-, Cl-, SO42-, NO3-, NH4+, Na+, K+, Ca2+, and Mg2+), pH and conductivity. In addition, bicarbonate (HCO3-) was also estimated. The mean pH values of the RW were >6 at Pune and <6 at Delhi and 4% and 26% were acidic, respectively. The mean sum of all measured ionic species in Pune and Delhi was 304.7 and 536.4 mu ep/l, respectively, indicating that significant atmospheric pollution effects in these Indian mega cities. Both the Ca2+ and SO42- were the dominant ions, accounting for 43% (Pune) and 54% (Delhi) of the total ions. The sum of measured ions during the NMN period was greater than the NM period by a factor of 1.5 for Pune (278.4: NM and 412.1: NMN mu eq/l) and a factor of about 2.5 for Delhi (406 and 1037.7 mu eq/l). The contributions of SO42- and NO3- to the RW acidity were similar to 40% and 60%, respectively, at Pune and correspondingly, 36% and 64% at Delhi. The concentrations of secondary aerosols (SO42- and NO3-) were higher by a factor of two and three when the air masses were transported to Pune from the continental side. At Delhi, the concentrations of SO42-, NO3-, Ca2+, and Mg2+ were significantly higher when the air masses arrive from Punjab, Haryana, and Pakistan indicating the greater atmospheric pollution over the Indo-Gangetic Plain. Positive matrix factorization was applied to the source apportionment of the deposition fluxes of these ions. Three factors were obtained for Pune and four for Delhi. The sources at Pune were secondary aerosols from fossil fuel combustion, soil dust, and marine, whereas, at Delhi, the sources were soil, fossil fuel combustion, biomass burning, and industrial chlorine.
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| 9. |
- Suresh, K.G., et al.
(författare)
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Tourism, trade, and economic growth in India : a frequency-domain analysis of causality
- 2018
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Ingår i: Anatolia. - : Routledge. - 1303-2917 .- 2156-6909. ; 29:3, s. 319-325
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Tidskriftsartikel (refereegranskat)abstract
- We examine causal relationships among the macroeconomic entities tourism and output dynamics in India, using the frequency–domain causality approach. Our results show that there is a bidirectional causality between openness and tourism as well as between output and tourism, at various frequency bands. Hence, this study suggests a multiplier effect of tourism on the Indian economy.
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| 10. |
- Tiwari, Suresh, et al.
(författare)
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Assessment of PM2.5 and PM10 over Guwahati in Brahmaputra River Valley : Temporal evolution, source apportionment and meteorological dependence
- 2017
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Ingår i: Atmospheric Pollution Research. - : Elsevier BV. - 1309-1042. ; 8:1, s. 13-28
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Tidskriftsartikel (refereegranskat)abstract
- Temporal evolution, source apportionment and transport pathways of particulate matter (PM2.5 and PM10) are analysed over Guwahati, located in the Brahmaputra River Valley (BRV), as a function of meteorological dynamics. During the study period (July 2013-June 2014), the mean PM2.5 and PM10 mass concentrations were found to be 52 +/- 37 and 91 +/- 60 mu g m (-3), respectively, both exhibiting higher concentrations during DecembereMarch and very low during summer. The annual mean ratio of PM2.5/ PM10 was 0.57 +/- 0.11, varying from 0.24 to 0.86, suggesting dominance of anthropogenic vs natural emissions during winter and spring, respectively. Diurnal variation reveals higher PM concentrations during morning (similar to 9: 00 local time (LT)) and evening (similar to 23: 00 LT) and lowest around similar to 14: 00 to 17: 00 LT due to influence of dilution processes and higher mixing-layer height over the region. Bivariate plots and Conditional Bivariate Probability Function (CBPF) analysis showed that the highest PM2.5 and PM10 concentrations are mostly associated with weak northwestern winds (< 1.5 ms (- 1)) in all seasons except spring, when the highest PM10 are for southwestern winds above 4-6 ms(- 1), indicating dust transport from SW Asia. Analysis reveals that the local emissions, transported aerosols, along with seasonallychanged air masses, meteorology and boundary-layer dynamics control the concentrations, evolution and fractions of PM over BRV. The turbid air masses transported over Guwahati mostly from western and southwestern directions contribute to higher PM concentrations, either carrying anthropogenic pollution from Indo-Gangetic Plains or locally and LRT dust from BRV and western India, respectively.
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| 11. |
- Tiwari, Suresh, et al.
(författare)
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Atmospheric heating due to black carbon aerosol during the summer monsoon period over Ballia : A rural environment over Indo-Gangetic Plain
- 2016
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Ingår i: Atmospheric research. - : Elsevier BV. - 0169-8095 .- 1873-2895. ; 178, s. 393-400
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Tidskriftsartikel (refereegranskat)abstract
- Black carbon (BC) aerosols are one of the most uncertain drivers of global climate change. The prevailing view is that BC mass concentrations are low in rural areas where industrialization and vehicular emissions are at a minimum. As part of a national research program called the Ganga Basin Ground Based Experiment-2014 under the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) Phase-III of Ministry of Earth Sciences, Government of India, the continuous measurements of BC and particulate matter (PM) mass concentrations, were conducted in a rural environment in the highly-polluted Indo-Gangetic Plain region during 16th June to 15th August (monsoon period), 2014. The mean mass concentration of BC was 4.03 (+/- 0.85) mu g m(-3) with a daily variability between 2.4 and 5.64 mu g m(-3), however, the mean mass PM concentrations [near ultrafine (PM1.0), fine (PM2.5) and inhalable (PM1.0)] were 29.1(+/- 16.2), 34.7 (+/- 19.9) and 43.7 (+/- 283) mu g m(-3), respectively. The contribution of BC in PM1.0 was approximately 13%, which is one of the highest being recorded. Diurnally, the BC mass concentrations were highest (mean: 5.89 mu g m(-3)) between 20:00 to 22:00 local time (LT) due to the burning of biofuels/biomass such as wood, dung, straw and crop residue mixed with dung by the local residents for cooking purposes. The atmospheric direct radiative forcing values due to the composite and BC aerosols were determined to be +78.3, +44.9, and +45.0 W m(-2) and +42.2, +35.4 and +34.3 W m(-2) during the months ofJune, July and August, respectively. The corresponding atmospheric heating rates (AHR) for composite and BC aerosols were 2.21,1.26 and 1.26; and 1.19, 0.99 and 0.96 K day(-1) for the month ofJune, July and August, respectively, with a mean of 1.57 and 1.05 K day(-1) which was 33% lower AHR (BC) than for the composite particles during the study period. This high AHR underscores the importance of absorbing aerosols such as BC contributed by residential cooking using biofuels in India. Our study demonstrates the need for immediate, effective regulations and policies that mitigate the emission of BC particles from domestic cooking in rural areas of India.
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| 12. |
- Tiwari, Suresh, et al.
(författare)
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Observations of ambient trace gas and PM10 concentrations at Patna, Central Ganga Basin during 2013-2014 : The influence of meteorological variables on atmospheric pollutants
- 2016
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Ingår i: Atmospheric research. - : Elsevier BV. - 0169-8095 .- 1873-2895. ; 180, s. 138-149
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric pollutants including ozone (O-3), sulfur dioxide (SO2), oxides of nitrogen (NOx), carbon monoxide (CO), and inhalable particulate matter (PM10) were measured in the central Indo-Gangetic Basin (IGB) at Patna, India, from 1st March 2013 to 31st December 2014, and significant variability was observed in the temporal patterns of these pollutant concentrations. The mean O-3, SO2, NO, NO2, CO (trace gases: TG), and PM10 (PM) concentrations were 14.5 +/- 4.8, 5.9 +/- 4.8, 23.1 +/- 22, 20.6 +/- 14.6 ppb, 1.5 +/- 0.7 ppm, and 192.0 +/- 132.8 ng/m(3), respectively, over the study period. The highest concentrations of these species were during the post-monsoon and winter seasons except O-3 and SO2 that showed the highest concentrations during the pre-monsoon. The lowest concentrations of TG and PM were observed during the monsoon season as a result of scavenging by rain. NO and NO2 along with PM concentrations decreased by similar to 76,19, and 63% when the wind speed (WS) was >0.5 m/s. However, for O-3, an opposite trend was observed with similar to 14% higher concentrations. The WS was negatively correlated with PM during the winter (-0.48) and post-monsoon (-0.32) seasons. In order to investigate the source region of TG and PM, 5-day air mass back trajectories were computed. The dominance of the air masses (92, 53, and 49%) were from the IGB is highly polluted during the winter, pre-monsoon, and post-monsoon, respectively. The TG and PM were observed much higher during these periods. During the biomass burning period (post-monsoon), the trajectory analysis showed that the TG and PM concentrations were around three-fold higher (flow from the IGB) than the other seasons. To improve air quality over IGB, the mitigation measures should be designed to reduce emissions from both local and regional sources.
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| 13. |
- Tiwari, Suresh, et al.
(författare)
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Significant cooling effect on the surface due to soot particles over Brahmaputra River Valley region, India : An impact on regional climate
- 2016
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 562, s. 504-516
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Tidskriftsartikel (refereegranskat)abstract
- Black carbon (BC) is an important atmospheric aerosol constituent that affects the climate by absorbing (directly) the sunlight and modifying cloud characteristics (indirectly). Here, we present first time yearlong measurements of BC and carbon monoxide (CO) from an urban location of Guwahati located in the Brahmaputra River valley (BRV) in the northeast region of India from 1st July 2013 to 30th June 2014. Daily BC concentrations varied within the range of 2.86 to 11.56 mu g m(-3) with an annual average of 7.17 +/- 1.89 mu g m(-3), while, CO varied from 0.19 to 1.20 ppm with a mean value of 0.51 +/- 0.19 ppm during the study period. The concentrations of BC (8.37 mu g m(-3)) and CO (0.67 ppm) were similar to 39% and similar to 55% higher during the dry months (October to March) than the wet months (April to September) suggesting that seasonal changes in meteorology and emission sources play an important role in controlling these species. The seasonal Delta BC/Delta CO ratios were highest (lowest) in the pre-monsoon (winter) 18.1 +/- 1.4 mu g m(-3) ppmv(-1) (12.6 +/- 2.2 mu g m(-3) ppmv(-1)) which indicate the combustion of biofuel/biomass as well as direct emissions from fossil fuel during the pre-monsoon season. The annual BC emission was estimated to be 2.72 Gg in and around Guwahati which is about 44% lower than the mega city 'Delhi' (4.86 Gg). During the study period, the annual mean radiative forcing (RF) at the top of the atmosphere (TOA) for clear skies of BC was +9.5Wm(-2), however, the RF value at the surface (SFC) was -21.1 Wm(-2) which indicates the net warming and cooling effects, respectively. The highest RF at SFC was in the month of April (-30 Wm(-2)) which is coincident with the highest BC mass level. The BC atmospheric radiative forcing (ARF) was +30.16 (annualmean) Wm(-2) varying from +23.1 to +43.8 Wm(-2). The annualmean atmospheric heating rate (AHR) due to the BC aerosols was 0.86 K day(-1) indicates the enhancement in radiation effect over the study region. The Weather Research and Forecasting model coupled with Chemistry(WRF-Chem) captured the seasonal cycle of observed BC fairly well but underestimated the observed BC during the month of May-August. Model results show that BC at Guwahati is controlled mainly by anthropogenic emissions except during the pre-monsoon season when open biomass burning also makes a similar contribution.
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| 14. |
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