Distribution of sulfur dioxide over Indian subcontinent: Remote sensing observations and model reanalysis (original) (raw)
Related papers
Seasonal Evolution of Sulfur Dioxide Over the Indian Subcontinent
URSI Radio Science Letters, 2021
Reanalysis, which combines the chemical-transport model with remote-sensing measurements, has shown potential to fill data gaps over observationally sparse regions of the globe. Here, the seasonal distribution of sulfur dioxide (SO 2) over the Indian region was analyzed for 2005-2015 period using Copernicus Atmosphere Monitoring Service (CAMS) reanalysis. CAMS reproduced general features and seasonality observed in surface SO 2 over this region. Elevated levels were revealed across the Indo-Gangetic Plain (IGP) and over eastern and central India. SO 2 shows a prominent seasonality over India, with a maximum typically during winter and a minimum during the summer monsoon. The winter maximum is attributed to weaker chemical sink, stagnant meteorological conditions, and elevated emissions, whereas wet scavenging, inflow of marine air, and stronger sulfate formation efficiency cause lower SO 2 during the monsoon. SO 2 levels exhibited an enhancement over IGP and central and eastern India, with rates in the range of 0.5 ppbv to 4 ppbv per decade. Like the distribution, trends also showed seasonal dependence, with weaker trends during the summer monsoon and stronger trends during the winter and postmonsoon. In situ observations of SO 2 and related species especially over the identified hot spots are recommended to validate satellite and model data sets and evaluate airquality and climate implications. 2. Data and Methodology 2.1 CAMS Model CAMS reanalysis provides consistent gridded fields of atmospheric composition based on an integrat
Long-Term Measurements of SO2 Over Delhi, India
MAPAN, 2019
Long-term measurements (2011-2018) of ambient sulphur dioxide (SO 2) and meteorology were carried out at an urban site of Delhi, India, to study the seasonal and inter-annual variations of SO 2 over Delhi. The average mixing ratio of SO 2 was estimated as 2.26 ± 0.48 ppb for the entire study period. Mixing ratio of ambient SO 2 was estimated as 2.19 ± 0.64 ppb, 2.07 ± 0.89 ppb, 2.49 ± 1.05 ppb and 2.27 ± 0.71 ppb during winter, pre-monsoon, monsoon and post-monsoon seasons, respectively. SO 2 mixing ratio was recorded maxima during monsoon (2.49 ± 1.05 ppb) season, whereas minima during pre-monsoon season (2.07 ± 0.89 ppb). The mixing ratio of SO 2 showed slightly increase in the trend during observational period. Surface wind speed and wind directions analysis indicates the influence of local sources on the mixing ratio of SO 2 at the study site. Backward trajectories and potential source contributing factor (PSCF) analysis also showed the local as well as the regional sources (industrial activities, coal burning and thermal power plants etc.,) influencing the mixing ratio of SO 2 over Delhi.
Pollution Research
Due to rapid economic growth, industrialization and urbanization, sulfur dioxide (SO2 ) from coalfired power plants in India has increased notably in the past decades. The present paper estimates and predicts the future sulphur dioxide (SO2 ) concentrations in Tamil Nadu, India by using PRECIS, a Regional Climate Model (RCM) developed by Hadley Centre –UK Met office. The model is run with 25 km × 25 km resolution using different baseline Lateral Boundary Conditions (LBCs) from the Global Climate Model (GCM) - HadCM3Q at the emission rate of SRES A1B scenarios. Results show that SO2 emissions in major industrial cities in Tamil Nadu increased dramatically by 40% during 2000–2012. It is estimated that, with current expectations on future economic development and with the present air quality legislation, anthropogenic emissions of SO2 for the whole Tamil Nadu would increase more between 2010 and 2030 and then may decrease by end of the century due to various pollution control measures ...
Atmospheric Chemistry and Physics
Convective transport plays a key role in aerosol enhancement in the upper troposphere and lower stratosphere (UTLS) over the Asian monsoon region where low-level convective instability persists throughout the year. We use the state-of-the-art ECHAM6-HAMMOZ global chemistryclimate model to investigate the seasonal transport of anthropogenic Asian sulfate aerosols and their impact on the UTLS. Sensitivity simulations for SO 2 emission perturbation over India (48 % increase) and China (70 % decrease) are performed based on the Ozone Monitoring Instrument (OMI) satellite-observed trend, rising over India by ∼ 4.8 % per year and decreasing over China by ∼ 7.0 % per year during 2006-2017. The enhanced Indian emissions result in an increase in aerosol optical depth (AOD) loading in the UTLS by 0.61 to 4.17 % over India. These aerosols are transported to the Arctic during all seasons by the lower branch of the Brewer-Dobson circulation enhancing AOD by 0.017 % to 4.8 %. Interestingly, a reduction in SO 2 emission over China inhibits the transport of Indian sulfate aerosols to the Arctic in summer-monsoon and post-monsoon seasons due to subsidence over northern India. The region of sulfate aerosol enhancement shows significant warming in the UTLS over northern India, south China (0.2 ± 0.15 to 0.8 ± 0.72 K) and the Arctic (∼ 1 ± 0.62 to 1.6 ± 1.07 K). The estimated seasonal mean direct radiative forcing at the top of the atmosphere (TOA) induced by the increase in Indian SO 2 emission is −0.2 to −1.5 W m −2 over northern India. The Chinese SO 2 emission reduction leads to a positive radiative forcing of ∼ 0.6 to 6 W m −2 over China. The decrease in vertical velocity and the associated enhanced stability of the upper troposphere in response to increased Indian SO 2 emissions will likely decrease rainfall over India.
Global and regional trends of atmospheric sulfur
Scientific Reports
Drew shindell 13 , Ragnhild B. skeie 10 , Ariel stein 14 , toshihiko takemura 15 , svetlana tsyro 2 , Robert Vet 16 & Xiaobin Xu 17 the profound changes in global so 2 emissions over the last decades have affected atmospheric composition on a regional and global scale with large impact on air quality, atmospheric deposition and the radiative forcing of sulfate aerosols. Reproduction of historical atmospheric pollution levels based on global aerosol models and emission changes is crucial to prove that such models are able to predict future scenarios. Here, we analyze consistency of trends in observations of sulfur components in air and precipitation from major regional networks and estimates from six different global aerosol models from 1990 until 2015. There are large interregional differences in the sulfur trends consistently captured by the models and observations, especially for North America and europe. europe had the largest reductions in sulfur emissions in the first part of the period while the highest reduction came later in North America and east Asia. the uncertainties in both the emissions and the representativity of the observations are larger in Asia. However, emissions from East Asia clearly increased from 2000 to 2005 followed by a decrease, while in India a steady increase over the whole period has been observed and modelled. the agreement between a bottom-up approach, which uses emissions and processbased chemical transport models, with independent observations gives an improved confidence in the understanding of the atmospheric sulfur budget. Germany.
Recent anthropogenic increases in SO 2 from Asia have minimal impact on stratospheric aerosol
Geophysical Research Letters, 2013
1] Observations suggest that the optical depth of the stratospheric aerosol layer between 20 and 30 km has increased 4-10% per year since 2000, which is significant for Earth's climate. Contributions to this increase both from moderate volcanic eruptions and from enhanced coal burning in Asia have been suggested. Current observations are insufficient to attribute the contribution of the different sources. Here we use a global climate model coupled to an aerosol microphysical model to partition the contribution of each. We employ model runs that include the increases in anthropogenic sulfur dioxide (SO 2 ) over Asia and the moderate volcanic explosive injections of SO 2 observed from 2000 to 2010. Comparison of the model results to observations reveals that moderate volcanic eruptions, rather than anthropogenic influences, are the primary source of the observed increases in stratospheric aerosol. Citation: Neely
Characterization of the seasonal cycle of south Asian aerosols: A regional-scale modeling analysis
Journal of Geophysical Research, 2007
The sulfur transport and deposition model (STEM) is used to study the aerosol seasonality, distribution, and composition over south Asia from September 2004 to August 2005. Model predictions of sulfate, black carbon, primary organic carbon, other anthropogenic particulate matter, windblown mineral dusts, and sea salt are compared at two sites in south Asia where yearlong experimental observations are available from the Atmospheric Brown Cloud (ABC) project. The model predictions are able to capture both the magnitude and seasonality of aerosols over Hanimaadhoo Observatory, Maldives. However, the model is not able to explain the seasonality at the Kathmandu Observatory; but the model does capture Kathmandu's observed annual mean concentration. The absence of seasonal brick kiln emissions within Kathmandu valley in the current inventory is a probable reason for this problem. This model study reveals high-anthropogenic aerosol loading over the Ganges valley even in the monsoonal months, which needs to be corroborated by experimental observations. Modeling results also show a high dust loading over south Asia with a distinct seasonality. Model results of aerosol monthly composition are also presented at five cities in south Asia. Total and fine-mode monthly aerosol optical depth along with contribution from each aerosol species is presented; the results show that the anthropogenic fraction dominates in the postmonsoon and the early dry season with major contributions from sulfate and absorbing aerosols. Model sensitivity studies of dry deposition velocity and wet scavenging efficiency show that model improvements are needed in the treatment of carbonaceous aerosol dry and wet removal processes. Modeled SO 2 conversion rate constrained with sulfate observations at Hanimaadhoo suggests the need to increase model sulfate production rate during the dry season to account for probable sulfate production via heterogeneous pathways.
High-resolution model simulations of anthropogenic sulphate and sulphur dioxide in Southeast Asia
Atmospheric Environment, 2005
The Multiple-scale Atmospheric Transport and CHemical modelling system (MATCH)-driven by meteorological data from the ECMWF-has been applied to a model domain covering Southeast Asia to complete a simulation extending over the full year of 2000. The current paper presents an evaluation of the model performance using archived chemical and meteorological data collected in the region during the year 2000. The calculated sulphate concentrations (on atmospheric aerosols and in precipitation) compare reasonably with observations while the atmospheric SO 2 mixing ratios show worse correspondence. This latter mismatch is attributed to local variations in the measured SO 2 concentrations that are not resolved in the regional model and possible miss-location of the emissions in our model. It can also be pointed out that different laboratories measuring SO 2 at the same site occasionally report SO 2 concentrations that differs by an order of magnitude or more.
We examined the spatio-temporal variability of atmospheric CO2 over India and its surrounding based on Goddard Earth Observation System Chemical (GEOS-Chem) transport model, satellite and in-situ observations. The model was employed at 2x2.5 0 spatial resolution over the globe with 47 vertical layers between pressure levels 1006-0.01 hPa. It is driven by GEOS meteorological fields along with surface boundary fluxes and anthropogenic emissions from different sources. The model run was performed for the period 2006-2013 and the solutions at three hourly intervals were stored for the analysis. In this paper, we are discussing the seasonal and inter-annual characteristics of simulated atmospheric CO2 highlighting the uncertainties associated with input data sets in the model. There exist good coherences between model and satellite observation. Simulated CO2 shows strong seasonality near the surface and has showed decrease in its amplitude upward. Amplitudes of the seasonal and annual cycles are stronger over the northern hemisphere, especially over the land regions.