This document summarizes a study that analyzed changes in aerosol pollution and climate during India's Holi festival using ground and satellite observations. Measurements at a site in Mumbai showed higher aerosol optical depth, water vapor, and lower solar radiation during the festival period compared to normal days, likely due to increased biomass burning and other activities. Parameters suggested an increase in smaller accumulation mode particles. Satellite data was consistent with transport of dust and smoke aerosols from biomass burning. Estimates indicated aerosols had a cooling effect at the bottom of the atmosphere.
Air Pollution A Case Study Of Ilorin And Lagos Outdoor AirErica Thompson
This document summarizes a study on air pollution in Ilorin and Lagos, Nigeria. The study analyzed data on ozone, nitrogen oxides, and sulfur dioxide collected from multiple monitoring sites in both cities from 2003-2006. Statistical analysis techniques like principal component analysis were used to identify pollution sources and trends. Meteorological data was also considered to establish prediction models for how weather influences seasonal variations in pollutant concentrations. The aim was to compare measured and modeled values to better understand air quality in the two cities.
Air Pollution A Case Study Of Ilorin And Lagos Outdoor AirSara Perez
This document summarizes a study on air pollution in Ilorin and Lagos, Nigeria. The study analyzed data on ozone, nitrogen oxides, and sulfur dioxide collected from multiple monitoring sites in both cities from 2003-2006. Statistical analysis techniques like principal component analysis were used to identify pollution sources and trends. Regression models were also used to predict the influence of meteorological factors on pollutant concentrations and establish seasonal variations. The goal was to compare measured and modeled pollutant values to better understand air quality in the two cities.
SOME STUDIES IN REGIONAL ENVIRONMENTAL AIR QUALITY MODELING, CLIMATE CHANGE A...grssieee
The document discusses a study using an air quality modeling system (WRF-CHEM) to analyze the impact of industrial emissions on ozone and particulate matter concentrations in the Jackson, Mississippi area from June 25-28, 2008. The model predicts a high ozone peak in the afternoon as well as fluctuating particulate matter concentrations. While ozone formation is independent of particulate matter, increased particulate matter may influence increased ozone production by enhancing precursor concentrations. The results help understand the relationship between industrial pollution, climate change, and health effects.
Particulate matter, air quality and climateYahsé Challa
This document reviews recent developments in particulate matter (PM) or atmospheric aerosol science and its connections to environmental policy issues. It summarizes that while PM has significant impacts on human health and climate, uncertainties remain regarding the relative importance of different PM components and sources. Reducing emissions of black carbon and ammonia could help mitigate some PM impacts cost-effectively. However, a prioritized plan to address the full range of PM effects is still needed due to gaps in understanding processes like global climate impacts and the response of PM precursors to future changes. The review advocates an integrated approach to air quality and climate policy given the evidence of PM's importance to both issues.
Introduction
The transport sectors, including land transport, shipping and
aviation, are major sources of atmospheric pollution (e.g.,
Righi et al., 2013). The emissions from transport are growing
more rapidly than those from the other anthropogenic activities.
According to the ATTICA assessment (Uherek et al.,
2010; Eyring et al., 2010), land transport and shipping shared
74 and 12 % of the global CO2 emissions from transport in
the year 2000, respectively. In the time period 1990–2007,
the EU-15 CO2-equivalent emissions from land transport and
shipping increased by 24 and 63 %, respectively. This growth
is expected to continue in the future, due to increasing world
population, economic activities and related mobility. The future
road traffic scenarios analyzed by Uherek et al. (2010)
essentially agree in projecting an increase of both fuel demand
and CO2 emissions until 2030, with up to a factor of
∼ 3 increase in CO2 emissions with respect to 2000. The ATTICA
assessment also showed that emissions of CO2 from
land transport and shipping affect the global climate by exerting
a radiative forcing (RF) effect of 171 (year 2000)
and 37 mW m−2
(year 2005), respectively. These two sectors
together account for 13 % of the total anthropogenic CO2
warming (year 2005).
In addition to long-lived greenhouse gases, ground-based
vehicles and ocean-going ships emit aerosol particles as well
as a wide range of short-lived gases, including also aerosol
precursor species. Atmospheric aerosol particles have significant
impacts on climate, through their interaction with solar
radiation and their ability to modify cloud microphysical
and optical properties (Forster et al., 2007). In populated areas,
they also affect air quality and human health (Pope and
Dockery, 2006; Chow et al., 2006).
The document discusses aerosols and their effects. It provides information on:
1. What aerosols are, including their natural and anthropogenic sources. Aerosols can affect climate directly by scattering and absorbing radiation, and indirectly by altering cloud properties.
2. The health impacts of aerosols, as they are a major component of smog. Epidemiological studies have shown correlations between elevated aerosol levels and increased mortality, hospital visits, and excess infant mortality.
3. The effects of black carbon aerosols specifically. Black carbon warms the atmosphere through absorption of sunlight and contributes to melting of snow and ice when deposited on their surfaces. It may be responsible for up to 40
The document discusses aerosols and their effects. It provides information on:
1) What aerosols are, including their natural and anthropogenic sources. Aerosols can affect climate directly by scattering and absorbing radiation, and indirectly by altering cloud properties.
2) The health impacts of aerosols, as they are a major component of smog. Epidemiological studies have shown correlations between elevated aerosol levels and increased mortality, hospital visits, and excess infant mortality.
3) The effects of black carbon aerosols specifically. Black carbon warms the atmosphere through absorption of sunlight and contributes to melting of snow and ice when deposited on their surfaces. It may be responsible for up to 40
The document discusses aerosols and their effects. It provides information on:
1. What aerosols are, including their natural and anthropogenic sources. Aerosols can affect climate, cloud formation, chemistry, and health.
2. The health effects of aerosols, including increased mortality from exposure to particulate air pollution and effects on respiratory health.
3. The impacts of black carbon aerosols specifically, including their role in global warming through absorption of sunlight, melting of snow and ice by lowering albedo, and effects on visibility and air quality.
Air Pollution A Case Study Of Ilorin And Lagos Outdoor AirErica Thompson
This document summarizes a study on air pollution in Ilorin and Lagos, Nigeria. The study analyzed data on ozone, nitrogen oxides, and sulfur dioxide collected from multiple monitoring sites in both cities from 2003-2006. Statistical analysis techniques like principal component analysis were used to identify pollution sources and trends. Meteorological data was also considered to establish prediction models for how weather influences seasonal variations in pollutant concentrations. The aim was to compare measured and modeled values to better understand air quality in the two cities.
Air Pollution A Case Study Of Ilorin And Lagos Outdoor AirSara Perez
This document summarizes a study on air pollution in Ilorin and Lagos, Nigeria. The study analyzed data on ozone, nitrogen oxides, and sulfur dioxide collected from multiple monitoring sites in both cities from 2003-2006. Statistical analysis techniques like principal component analysis were used to identify pollution sources and trends. Regression models were also used to predict the influence of meteorological factors on pollutant concentrations and establish seasonal variations. The goal was to compare measured and modeled pollutant values to better understand air quality in the two cities.
SOME STUDIES IN REGIONAL ENVIRONMENTAL AIR QUALITY MODELING, CLIMATE CHANGE A...grssieee
The document discusses a study using an air quality modeling system (WRF-CHEM) to analyze the impact of industrial emissions on ozone and particulate matter concentrations in the Jackson, Mississippi area from June 25-28, 2008. The model predicts a high ozone peak in the afternoon as well as fluctuating particulate matter concentrations. While ozone formation is independent of particulate matter, increased particulate matter may influence increased ozone production by enhancing precursor concentrations. The results help understand the relationship between industrial pollution, climate change, and health effects.
Particulate matter, air quality and climateYahsé Challa
This document reviews recent developments in particulate matter (PM) or atmospheric aerosol science and its connections to environmental policy issues. It summarizes that while PM has significant impacts on human health and climate, uncertainties remain regarding the relative importance of different PM components and sources. Reducing emissions of black carbon and ammonia could help mitigate some PM impacts cost-effectively. However, a prioritized plan to address the full range of PM effects is still needed due to gaps in understanding processes like global climate impacts and the response of PM precursors to future changes. The review advocates an integrated approach to air quality and climate policy given the evidence of PM's importance to both issues.
Introduction
The transport sectors, including land transport, shipping and
aviation, are major sources of atmospheric pollution (e.g.,
Righi et al., 2013). The emissions from transport are growing
more rapidly than those from the other anthropogenic activities.
According to the ATTICA assessment (Uherek et al.,
2010; Eyring et al., 2010), land transport and shipping shared
74 and 12 % of the global CO2 emissions from transport in
the year 2000, respectively. In the time period 1990–2007,
the EU-15 CO2-equivalent emissions from land transport and
shipping increased by 24 and 63 %, respectively. This growth
is expected to continue in the future, due to increasing world
population, economic activities and related mobility. The future
road traffic scenarios analyzed by Uherek et al. (2010)
essentially agree in projecting an increase of both fuel demand
and CO2 emissions until 2030, with up to a factor of
∼ 3 increase in CO2 emissions with respect to 2000. The ATTICA
assessment also showed that emissions of CO2 from
land transport and shipping affect the global climate by exerting
a radiative forcing (RF) effect of 171 (year 2000)
and 37 mW m−2
(year 2005), respectively. These two sectors
together account for 13 % of the total anthropogenic CO2
warming (year 2005).
In addition to long-lived greenhouse gases, ground-based
vehicles and ocean-going ships emit aerosol particles as well
as a wide range of short-lived gases, including also aerosol
precursor species. Atmospheric aerosol particles have significant
impacts on climate, through their interaction with solar
radiation and their ability to modify cloud microphysical
and optical properties (Forster et al., 2007). In populated areas,
they also affect air quality and human health (Pope and
Dockery, 2006; Chow et al., 2006).
The document discusses aerosols and their effects. It provides information on:
1. What aerosols are, including their natural and anthropogenic sources. Aerosols can affect climate directly by scattering and absorbing radiation, and indirectly by altering cloud properties.
2. The health impacts of aerosols, as they are a major component of smog. Epidemiological studies have shown correlations between elevated aerosol levels and increased mortality, hospital visits, and excess infant mortality.
3. The effects of black carbon aerosols specifically. Black carbon warms the atmosphere through absorption of sunlight and contributes to melting of snow and ice when deposited on their surfaces. It may be responsible for up to 40
The document discusses aerosols and their effects. It provides information on:
1) What aerosols are, including their natural and anthropogenic sources. Aerosols can affect climate directly by scattering and absorbing radiation, and indirectly by altering cloud properties.
2) The health impacts of aerosols, as they are a major component of smog. Epidemiological studies have shown correlations between elevated aerosol levels and increased mortality, hospital visits, and excess infant mortality.
3) The effects of black carbon aerosols specifically. Black carbon warms the atmosphere through absorption of sunlight and contributes to melting of snow and ice when deposited on their surfaces. It may be responsible for up to 40
The document discusses aerosols and their effects. It provides information on:
1. What aerosols are, including their natural and anthropogenic sources. Aerosols can affect climate, cloud formation, chemistry, and health.
2. The health effects of aerosols, including increased mortality from exposure to particulate air pollution and effects on respiratory health.
3. The impacts of black carbon aerosols specifically, including their role in global warming through absorption of sunlight, melting of snow and ice by lowering albedo, and effects on visibility and air quality.
1) The document analyzes surface ozone levels measured over 12 months in Suchindrum, India.
2) Surface ozone levels showed clear diurnal and seasonal variations, with maximum levels in the afternoon and summer.
3) A neural network model was developed to predict peak afternoon ozone levels based on morning meteorological parameters, achieving good correlation between observed and predicted values.
1) The study measured air pollution levels over two years in residential areas in and around Tirupati, India, a popular pilgrimage site that sees over 1 million visitors monthly.
2) Suspended particulate matter (SPM) and respirable particulate matter (PM10) violated national air quality standards, while carbon monoxide levels approached the limit. Sulfur dioxide and nitrogen oxides were within standards.
3) Peak pollution occurred in spring and winter. Summer pollution levels exceeded monsoon and winter levels for most pollutants, influenced both by local factors and meteorology. Overall pollutant levels correlated with each other and with meteorological parameters.
Modification and Climate Change Analysis of surrounding Environment using Rem...iosrjce
This document discusses the application of remote sensing (RS) and geographic information systems (GIS) in analyzing climate change and the surrounding environment. It begins by defining key terms related to climate, climate change, and RS and GIS. It then highlights several areas where RS and GIS have been applied, including glacier monitoring, vegetation change monitoring, and carbon trace/accounting. Studies are discussed that use RS and GIS to monitor glacier retreat, snow depth, land cover change, and above-ground carbon stocks. The document concludes that RS and GIS play a crucial role in understanding and managing climate change by providing important spatial data and enabling the monitoring of environmental changes over time.
Remote sensing and GIS tools can be effectively used to analyze and monitor climate change and its effects in several areas:
1) Glacier and snow monitoring through analysis of satellite images to track glacier retreat and advance over time, as well as measuring snow depth, both of which are sensitive to climate change.
2) Vegetation change monitoring using multi-temporal satellite imagery to detect land degradation and changes in vegetation phenology correlated with climate patterns like rainfall.
3) Carbon accounting and tracing, important for climate change mitigation, through high-resolution mapping of above-ground carbon stocks using field measurements, airborne LiDAR, and satellite data.
Atmospheric Pollution Concentrations Over The Eastern Mediterranean During Su...Lisa Cain
This document contains the author's responses to comments on their paper "Atmospheric pollution concentrations over the Eastern Mediterranean during summer – A review" by a referee. The authors thank the referee for their insightful comments and make several changes to address the comments. The referee provided 17 comments addressing aspects of the paper such as the need to broaden discussions to include more regions of the Eastern Mediterranean, clarify terminology, and restructure some sections for improved flow and balance. The authors agree with the referee's points and describe edits they have made to the paper to address each comment.
A Good Climate For Clean Air Linkages Between Climate Change And Air Polluti...Monica Waters
This document discusses the linkages between climate change and air pollution, which have largely been separated in scientific research and policy negotiations despite being closely related. It outlines several types of linkages: common sources, interactions in the atmosphere, and intertwined environmental effects. Addressing climate change and air pollution simultaneously could reduce costs and risks to health and ecosystems. The document calls for more integrated scientific research and policy development that incorporates these linkages.
The document discusses atmospheric aerosols and their characterization. It notes that aerosols have complex physicochemical properties and their full characterization requires measuring multiple dimensions such as size, composition, shape, and mixing state. Satellite data has helped characterize the global distribution of aerosols but challenges remain in integrating different data sources. Aerosols originate from both natural sources like dust, fires and volcanoes as well as human activities and influence factors like climate, air quality and human health.
This document discusses the causes of climate change, including both natural causes and human causes. Natural causes include volcanic eruptions, ocean currents, changes in the Earth's orbit and axis, and continental drift. Human causes mainly consist of emitting greenhouse gases like carbon dioxide, methane, and nitrous oxide through activities such as burning fossil fuels, deforestation, agriculture, industrial processes, and coal mining. While climate change has occurred naturally in the past, human activities since the industrial era have increased greenhouse gas concentrations and accelerated global warming. Effective policy is needed to transition to renewable energy and more sustainable practices.
What are some of the basic principles and terminology involved in climate change? Learn more about the Earth's atmosphere, energy balance, and how the greenhouse effect can alter both climate and weather. What is climate forcing? What is climate feedback? For more on this topic, visit: http://extension.org/60702
This document summarizes a study that analyzes urban heat islands (UHI) and their impact on surface temperature over time in two regions - Haridwar district in Uttarakhand, India and Kanpur district in Uttar Pradesh, India. Satellite imagery from 1989, 2000 and 2006 was used to calculate normalized difference vegetation index (NDVI) values and estimate surface temperature. The results demonstrate a correlation between decreasing NDVI values and increasing surface temperature over time, likely due to urbanization and loss of vegetation cover. The research highlights the importance of considering environmental impacts when planning urban development.
Anthropogenic And Natural CO2 Emission Sources In An Arid Urban EnvironmentTye Rausch
Human and automobile activity produced more than 80% of the carbon dioxide inputs into the urban environment of Phoenix, Arizona. Soil CO2 efflux, or emissions, from human-maintained landscapes like golf courses, lawns, and irrigated agriculture were higher than from natural desert ecosystems, and were dependent on both temperature and soil moisture. Landfills exhibited the most consistent soil CO2 efflux rates but were independent of temperature and moisture. An analysis using GIS estimated the annual CO2 released from the predominant land-use types in the Phoenix region, with agriculture accounting for over 60% of total soil CO2 emissions from land-based sources.
This document provides an overview of atmospheric pollution and the structure and composition of the atmosphere. It discusses the different sources of air pollution, including mobile, stationary, area, and natural sources. It then describes the layers of the atmosphere from troposphere to exosphere, including details on temperature and pressure profiles. Key components like the ozone layer and ionosphere are explained. Processes such as photosynthesis, photolysis, and photoionization are also summarized.
Analysis of Stratospheric Tropospheric Intrusion as a Function of Potential V...Kalaivanan Murthy
The document provides a summary of a project report on assessing the vulnerability of stratospheric intrusions occurring in the United States based on topographic and meteorological characteristics. Stratospheric intrusions occur when stratospheric air masses diffuse into the troposphere, increasing ground-level ozone concentrations. The report discusses modeling such occurrences by analyzing potential vorticity in air masses and computing likelihood factors for different geographic grids in the US. It also reviews past stratospheric intrusion events and the importance of predicting future events for environmental regulation.
2003-08-30 Global and Local Dust over N. America Observations and Analysis ToolsRudolf Husar
The global dust system occupies dimensions of space, time, size, composition, shape and mixtures. New observational tools like satellites and surface networks monitor the daily aerosol pattern and transport but characterize only aspects of the full system. Data from multiple sensors along with models are needed to understand the system and derive knowledge. Analysis shows fine Saharan dust over southeast US averages 0.2-1 micrograms/m3 annually with July peaks of 2-6 micrograms/m3. During major transport events, surface dust over parts of North America can reach 50-100 micrograms/m3. These events significantly impact regional aerosol patterns. Establishing transcontinental dust sources requires open data sharing and scientific collaboration to decompose and integrate
diurnal temperature range trend over North Carolina and the associated mechan...Sayem Zaman, Ph.D, PE.
This study seeks to investigate the variability and presence of trends in the diurnal surface air temperature range
(DTR) over North Carolina (NC) for the period 1950–2009. The significance trend test and the magnitude of trends were determined using the non-parametric Mann–Kendall test and the Theil–Sen approach, respectively.
Statewide significant trends (p b 0.05) of decreasing DTR were found in all seasons and annually during the analysis period. The highest (lowest) temporal DTR trends of magnitude −0.19 (−0.031) °C/decade were found in summer (winter). Potential mechanisms for the presence/absence of trends in DTR have been highlighted. Historical
data sets of the three main moisture components (precipitation, total cloud cover (TCC), and soil moisture) and
the two major atmospheric circulation modes (North Atlantic Oscillation and Southern Oscillation) were used for
correlation analysis. The DTRs were found to be negatively correlated with the precipitation, TCC, and soil moisture across the state for all the seasons and annual basis. It appears that the moisture components related better to the DTR than to the atmospheric circulation modes.
This document summarizes a study that estimated solar UV-B radiation levels at Visakhapatnam, India from 2005-2013 using a regression model incorporating satellite-measured column ozone levels and solar zenith angle. The model was developed using earlier UV-B measurements and ozone data from 1989-1993. Analysis found seasonal variations in ozone but no significant long-term trends in estimated UV-B levels. The study concluded the data could help assess biological effects of UV-B radiation at this location over time.
1) Long-term monitoring has shown that total soil respiration is higher in urban forests compared to rural forests in Baltimore. This study aims to determine if differences in earthworm abundance explain the higher respiration levels.
2) Field measurements of soil respiration, moisture, biomass, organic matter, and earthworm abundance were taken at urban and rural forest sites. Earthworms were extracted using a mustard solution.
3) Preliminary results showed earthworm biomass was higher in urban sites, suggesting higher respiration in urban forests could be due to earthworm respiration and stimulation of root respiration by earthworms. Earthworm abundance varied with soil moisture.
2003-10-10 Measurement of free iron content in desert dust : effect on light ...Rudolf Husar
The atmospheric dust system has at least 8 dimensions including spatial, temporal, size, composition, shape, and mixture. New observational tools like satellites and surface networks allow monitoring of the global daily aerosol pattern and transport, but each sensor resolves some dimensions and integrates over others. Data and analysis tools from multiple sources can help characterize the dust system and derive knowledge about sources and processes. Current evidence allows estimation of transcontinental dust transport to North America, with average yearly Saharan dust over the southeast US around 0.2-1 μg/m3 and July peaks of 2-6 μg/m3. Specific transcontinental dust episodes from Africa and Asia can approach 50-100 μg/m3 over large regions. These
Simulation of atmospheric mercury dispersion and deposition in Tehran cityMohammadaminVahidi
In this study, dispersion and deposition of atmospheric mercury (Hg) in Tehran city was simulated using WRF-SMOKE-CMAQ models. The Weather Research and Forecasting (WRF) model was used to simulate the meteorological parameters. For validation of WRF results; the simulated wind speeds and temperatures were compared with the parameters measured at a meteorological station in Tehran city for 11 days (8 days in fall and 3 days in winter) in 2010 - 2011. The correlation coefficient (r) for temperature and wind speed were 0.94 and 0.49, respectively indicating there was good agreement between measured and modeled results. An atmospheric mercury emission inventory was developed using the United Nations Environment Programme (UNEP), the United States Environmental Protection Agency AP-42 (US-EPA AP-42) and related papers. Sparse Matrix Operator Kernel Emissions (SMOKE) was used to allocate the atmospheric mercury emissions to the modeling domain and the Community Multiscale Air Quality (CMAQ) model was used to simulate the concentration and deposition of atmospheric mercury. To validate the results of the CMAQ model, the simulated atmospheric particulate mercury (PHg) concentrations for 11 days were compared with the measured results at two different stations (Bagh Ferdows and Bahman Square) where it was measured by the Tehran Air Quality Control Company (AQCC). Comparison between the results from the modeled and measurements of PHg in fall was better than winter. Concentrations and dry depositions of the various forms of atmospheric mercury were higher in areas closer to mercury stationary emission sources.
The document provides instructions for a lab experiment to test the relationship between current, force, and length of a conductor wire by passing a current through a wire near magnets. Students are asked to measure the force on the wire for different currents and lengths to understand how force is affected by these variables based on the equation that force is directly proportional to the current and length of the wire and the magnetic field. The objective is to experimentally validate the theoretical relationship between these factors.
Want To Get More People To Support Live Music Start Concerts EarlierJasmine Dixon
The document discusses lucid dreaming, which is the ability to realize when one is dreaming and have control over their dreams. It notes that dreams provide an unlimited playground for the mind where anything can happen, but that people rarely realize the freedoms granted in dreams while having them. Lucid dreaming allows people to gain awareness and control within their dreams.
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Similaire à Aerosol Pollution And Its Impact On Regional Climate During Holi Festival Inferred From Ground-Based And Satellite Remote Sensing Observations
1) The document analyzes surface ozone levels measured over 12 months in Suchindrum, India.
2) Surface ozone levels showed clear diurnal and seasonal variations, with maximum levels in the afternoon and summer.
3) A neural network model was developed to predict peak afternoon ozone levels based on morning meteorological parameters, achieving good correlation between observed and predicted values.
1) The study measured air pollution levels over two years in residential areas in and around Tirupati, India, a popular pilgrimage site that sees over 1 million visitors monthly.
2) Suspended particulate matter (SPM) and respirable particulate matter (PM10) violated national air quality standards, while carbon monoxide levels approached the limit. Sulfur dioxide and nitrogen oxides were within standards.
3) Peak pollution occurred in spring and winter. Summer pollution levels exceeded monsoon and winter levels for most pollutants, influenced both by local factors and meteorology. Overall pollutant levels correlated with each other and with meteorological parameters.
Modification and Climate Change Analysis of surrounding Environment using Rem...iosrjce
This document discusses the application of remote sensing (RS) and geographic information systems (GIS) in analyzing climate change and the surrounding environment. It begins by defining key terms related to climate, climate change, and RS and GIS. It then highlights several areas where RS and GIS have been applied, including glacier monitoring, vegetation change monitoring, and carbon trace/accounting. Studies are discussed that use RS and GIS to monitor glacier retreat, snow depth, land cover change, and above-ground carbon stocks. The document concludes that RS and GIS play a crucial role in understanding and managing climate change by providing important spatial data and enabling the monitoring of environmental changes over time.
Remote sensing and GIS tools can be effectively used to analyze and monitor climate change and its effects in several areas:
1) Glacier and snow monitoring through analysis of satellite images to track glacier retreat and advance over time, as well as measuring snow depth, both of which are sensitive to climate change.
2) Vegetation change monitoring using multi-temporal satellite imagery to detect land degradation and changes in vegetation phenology correlated with climate patterns like rainfall.
3) Carbon accounting and tracing, important for climate change mitigation, through high-resolution mapping of above-ground carbon stocks using field measurements, airborne LiDAR, and satellite data.
Atmospheric Pollution Concentrations Over The Eastern Mediterranean During Su...Lisa Cain
This document contains the author's responses to comments on their paper "Atmospheric pollution concentrations over the Eastern Mediterranean during summer – A review" by a referee. The authors thank the referee for their insightful comments and make several changes to address the comments. The referee provided 17 comments addressing aspects of the paper such as the need to broaden discussions to include more regions of the Eastern Mediterranean, clarify terminology, and restructure some sections for improved flow and balance. The authors agree with the referee's points and describe edits they have made to the paper to address each comment.
A Good Climate For Clean Air Linkages Between Climate Change And Air Polluti...Monica Waters
This document discusses the linkages between climate change and air pollution, which have largely been separated in scientific research and policy negotiations despite being closely related. It outlines several types of linkages: common sources, interactions in the atmosphere, and intertwined environmental effects. Addressing climate change and air pollution simultaneously could reduce costs and risks to health and ecosystems. The document calls for more integrated scientific research and policy development that incorporates these linkages.
The document discusses atmospheric aerosols and their characterization. It notes that aerosols have complex physicochemical properties and their full characterization requires measuring multiple dimensions such as size, composition, shape, and mixing state. Satellite data has helped characterize the global distribution of aerosols but challenges remain in integrating different data sources. Aerosols originate from both natural sources like dust, fires and volcanoes as well as human activities and influence factors like climate, air quality and human health.
This document discusses the causes of climate change, including both natural causes and human causes. Natural causes include volcanic eruptions, ocean currents, changes in the Earth's orbit and axis, and continental drift. Human causes mainly consist of emitting greenhouse gases like carbon dioxide, methane, and nitrous oxide through activities such as burning fossil fuels, deforestation, agriculture, industrial processes, and coal mining. While climate change has occurred naturally in the past, human activities since the industrial era have increased greenhouse gas concentrations and accelerated global warming. Effective policy is needed to transition to renewable energy and more sustainable practices.
What are some of the basic principles and terminology involved in climate change? Learn more about the Earth's atmosphere, energy balance, and how the greenhouse effect can alter both climate and weather. What is climate forcing? What is climate feedback? For more on this topic, visit: http://extension.org/60702
This document summarizes a study that analyzes urban heat islands (UHI) and their impact on surface temperature over time in two regions - Haridwar district in Uttarakhand, India and Kanpur district in Uttar Pradesh, India. Satellite imagery from 1989, 2000 and 2006 was used to calculate normalized difference vegetation index (NDVI) values and estimate surface temperature. The results demonstrate a correlation between decreasing NDVI values and increasing surface temperature over time, likely due to urbanization and loss of vegetation cover. The research highlights the importance of considering environmental impacts when planning urban development.
Anthropogenic And Natural CO2 Emission Sources In An Arid Urban EnvironmentTye Rausch
Human and automobile activity produced more than 80% of the carbon dioxide inputs into the urban environment of Phoenix, Arizona. Soil CO2 efflux, or emissions, from human-maintained landscapes like golf courses, lawns, and irrigated agriculture were higher than from natural desert ecosystems, and were dependent on both temperature and soil moisture. Landfills exhibited the most consistent soil CO2 efflux rates but were independent of temperature and moisture. An analysis using GIS estimated the annual CO2 released from the predominant land-use types in the Phoenix region, with agriculture accounting for over 60% of total soil CO2 emissions from land-based sources.
This document provides an overview of atmospheric pollution and the structure and composition of the atmosphere. It discusses the different sources of air pollution, including mobile, stationary, area, and natural sources. It then describes the layers of the atmosphere from troposphere to exosphere, including details on temperature and pressure profiles. Key components like the ozone layer and ionosphere are explained. Processes such as photosynthesis, photolysis, and photoionization are also summarized.
Analysis of Stratospheric Tropospheric Intrusion as a Function of Potential V...Kalaivanan Murthy
The document provides a summary of a project report on assessing the vulnerability of stratospheric intrusions occurring in the United States based on topographic and meteorological characteristics. Stratospheric intrusions occur when stratospheric air masses diffuse into the troposphere, increasing ground-level ozone concentrations. The report discusses modeling such occurrences by analyzing potential vorticity in air masses and computing likelihood factors for different geographic grids in the US. It also reviews past stratospheric intrusion events and the importance of predicting future events for environmental regulation.
2003-08-30 Global and Local Dust over N. America Observations and Analysis ToolsRudolf Husar
The global dust system occupies dimensions of space, time, size, composition, shape and mixtures. New observational tools like satellites and surface networks monitor the daily aerosol pattern and transport but characterize only aspects of the full system. Data from multiple sensors along with models are needed to understand the system and derive knowledge. Analysis shows fine Saharan dust over southeast US averages 0.2-1 micrograms/m3 annually with July peaks of 2-6 micrograms/m3. During major transport events, surface dust over parts of North America can reach 50-100 micrograms/m3. These events significantly impact regional aerosol patterns. Establishing transcontinental dust sources requires open data sharing and scientific collaboration to decompose and integrate
diurnal temperature range trend over North Carolina and the associated mechan...Sayem Zaman, Ph.D, PE.
This study seeks to investigate the variability and presence of trends in the diurnal surface air temperature range
(DTR) over North Carolina (NC) for the period 1950–2009. The significance trend test and the magnitude of trends were determined using the non-parametric Mann–Kendall test and the Theil–Sen approach, respectively.
Statewide significant trends (p b 0.05) of decreasing DTR were found in all seasons and annually during the analysis period. The highest (lowest) temporal DTR trends of magnitude −0.19 (−0.031) °C/decade were found in summer (winter). Potential mechanisms for the presence/absence of trends in DTR have been highlighted. Historical
data sets of the three main moisture components (precipitation, total cloud cover (TCC), and soil moisture) and
the two major atmospheric circulation modes (North Atlantic Oscillation and Southern Oscillation) were used for
correlation analysis. The DTRs were found to be negatively correlated with the precipitation, TCC, and soil moisture across the state for all the seasons and annual basis. It appears that the moisture components related better to the DTR than to the atmospheric circulation modes.
This document summarizes a study that estimated solar UV-B radiation levels at Visakhapatnam, India from 2005-2013 using a regression model incorporating satellite-measured column ozone levels and solar zenith angle. The model was developed using earlier UV-B measurements and ozone data from 1989-1993. Analysis found seasonal variations in ozone but no significant long-term trends in estimated UV-B levels. The study concluded the data could help assess biological effects of UV-B radiation at this location over time.
1) Long-term monitoring has shown that total soil respiration is higher in urban forests compared to rural forests in Baltimore. This study aims to determine if differences in earthworm abundance explain the higher respiration levels.
2) Field measurements of soil respiration, moisture, biomass, organic matter, and earthworm abundance were taken at urban and rural forest sites. Earthworms were extracted using a mustard solution.
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Aerosol Pollution And Its Impact On Regional Climate During Holi Festival Inferred From Ground-Based And Satellite Remote Sensing Observations
1. ORIGINAL PAPER
Aerosol pollution and its impact on regional climate
during Holi festival inferred from ground-based
and satellite remote sensing observations
C. P. Simha • P. C. S. Devara • S. K. Saha
Received: 22 May 2012 / Accepted: 23 May 2013
Ó Springer Science+Business Media Dordrecht 2013
Abstract In this paper, we report some salient features from a suit of special experiments
that have been conducted over a coastal site (Mumbai) during February 23–March 03, 2010,
encompassing an Indian festival, namely Holi, using solar radiometers and pyranometer. The
results of the analysis of observations at the experimental site show higher (more than
double) aerosol optical depth, water vapor, and lower down-welling short-wave radiative
flux during the festival period. This is considered to be due to anthropogenic activities and
associated meteorological conditions at the experimental location. To illustrate further,
Angstrom parameters (alpha, denoting the aerosol size distribution, and beta, representing
the loading) are examined. These parameters are found to be greater on Holi day as compared
to those on the normal (control, pre-, and post-Holi) days, suggesting an increase in accu-
mulation mode (smaller size) particle loading. The aerosol size spectra exhibited bimodal/
power-law distribution with a dominant peak, modulated by anthropogenic activities,
involving local and long-range transport of dust and smoke (emanated from biomass-
burning) aerosols, which is consistent with MODIS satellite observations. The aerosol direct
radiative forcing estimation indicated cooling at the bottom of the atmosphere.
Keywords Aerosols Ozone Precipitable water content Angstrom exponent
Holi festival MODIS Surface aerosol radiative forcing Meteorological parameters
Climate change
1 Introduction
Anthropogenic emissions are major sources of atmospheric aerosols. Aerosol pollutants
can adversely affect human health and also have impacts on climate and precipitation on a
regional scale (Penner and Novakov 1996). Natural sources such as volcanoes are also a
large source of aerosols and have been linked to changes in the earth’s climate, often with
C. P. Simha P. C. S. Devara () S. K. Saha
Indian Institute of Tropical Meteorology, Dr. Homi Bhabha Road, Pune 411 008, India
e-mail: devara@tropmet.res.in
123
Nat Hazards
DOI 10.1007/s11069-013-0743-6
2. consequences for the human population. The increased levels of fine particles in the air as a
result of anthropogenic activities are consistently and independently related to the most
serious effects, including lung cancer and other cardiopulmonary mortality. The effects of
inhaling fine particles that have been widely studied in humans and animals now include
asthma, lung cancer, cardiovascular issues, respiratory deceases, birth defects, and pre-
mature deaths (Pope et al. 2002). Biomass-burning, which is widely prevalent in the
tropics, serves to clear land for shifting cultivation and expanding population (Dwyer et al.
1998). Anthropogenic activities of this kind during festival periods over urban/metropol-
itan cities deteriorate local/regional air pollution, visibility, and human health issues. It
produces large amounts of trace gases and aerosol particles, which play a pivotal role in
tropospheric chemistry and climate (Arola et al. 2007, Crutzen and Andreae 1990). Aerosol
particles emitted from biomass-burning will also act as major source of cloud condensation
nuclei (CCN), which affect the microphysics of boundary-layer clouds and hence the
radiation budget of the earth by increasing the albedo (Penner and Novakov 1996). Smoke
particles and generation from heat from biomass-burning may have a significant impact on
(modulate) local meteorology (for example, Devara et al. 1994) and in turn on climate by
altering the global radiation balance. Each year, more than 100 million tons of smoke
aerosols are released into the atmosphere as a result of biomass-burning (Hao and Liu
1994). More than 80% of this burning activity in the tropical regions produces submicron
smoke aerosols that play a major role in the radiation balance of the earth–atmosphere
system (Balis et al. 2004; Kaufman and Nobre 1998). Because of this, they reflect
incoming solar radiation back to space, thereby reducing the amount of sunlight reaching
the earth’s surface (Christopher et al. 2000; Reid et al. 2005a, b).
2 Holi festival
Festival activities in every country perturb the radiation balance between the earth and
atmosphere due to additional anthropogenic activities in different ways. ‘Holi,’ the festival
of colors, is one such major festival in India. It is celebrated usually in the months of
February and March. It is mainly associated with the burning of Holika, and people
celebrate the festival by smearing each other with paint, and throwing colored powder and
dye around in an atmosphere of great good humor. On this occasion, the firewood is
arranged in a huge pile at a clearing in the locality. In the evening, the fire is lit. Then, high
concentrations of anthropogenic aerosols and toxic material are injected into the atmo-
sphere due to colored powder and fireworks, especially in urban regions. Thus, vast
amounts of various chemicals and particulate matter enter into the atmosphere. Some
chemicals which are in the Aitken nuclei range (0.01–0.1 lm) convert into the accumu-
lation mode (0.1–1 lm) particles by means of gas-to-particle conversion processes and
affect the atmospheric temperature and incoming solar flux.
Some researchers (Martin 2007; Lelieveld et al. 2001) pointed out that the Bombay
plumes during the winter monsoon transport black carbon-rich air from Western/Northwest
India over the Arabian Sea (AS). Thus, Mumbai is a source of anthropogenic aerosols such as
CO and VOCs (black carbon) as well as NOx and O3 (Phadnis et al. 2002). Ramachandran
(2004) reported that columnar AOD increases with increase in the marine boundary-layer
aerosol concentrations over coastal India and Arabian Sea, while an opposite trend is seen
over tropical Indian Ocean. The differences in the surface and columnar measurements could
also occur due to changes in the meteorological conditions in addition to changes in pro-
duction and subsequently the transport of aerosols. Aerosol extinction and mass measured
Nat Hazards
123
3. over coastal India, the Arabian Sea, and the tropical Indian Ocean are found to show large
spatial variations during the winter monsoon (Moorthy et al. 2001; Ramanathan et al. 2001;
Ramachandran and Jayaraman 2002; Ramachandran 2004). The 5-year mean (1996–2000)
variations show that the aerosol mass concentrations over coastal India in the coarse,
accumulation, and nucleation modes are higher than those measured over the Arabian Sea
and the tropical Indian Ocean (Ramachandran and Jayaraman 2003). Studies by Krish-
namurti et al. (1997) have identified the dominant flow in the region at lower levels as
northeasterly during winter monsoon months. Due to the limited knowledge of aerosol
sources, composition, properties, and processes, the actual effects of aerosols on climate and
health are still far from being fully understood. In this paper, we report some of the char-
acteristic features such as relative changes in aerosol loading, size distribution, and radiative
forcing exerted by these modified aerosols at the earth’s surface over the coastal region of the
metropolitan city (Mumbai, formerly known as Bombay). Some of these features have been
compared with concurrent space-borne (MODIS) measurements during the study period.
3 Experimental site
The experimental location (Mumbai) is situated about midway on the western coast of
India (19°230
N, 72°500
E) and is a peninsular city joining the mainland at its northern end
(Fig. 1). Large petrochemical, fertilizer, and power plants are located to the eastern and
Fig. 1 Map showing the location (Star) of the experimental site
Nat Hazards
123
4. southeastern sectors of the city. Several thousand medium and small-scale industries are
located in the city including chemical, textile and dyeing, pharmaceutical, paint and pig-
ment, and metal-working industries. The land-use pattern is industrial-cum-residential with
a total population of over 10 million and a population density of 16,500 persons Km-2
.
Sources of particulate matter in the city include vehicular emissions, power plants,
industrial oil burning, and refuse burning plants (Larssen et al. 1997). Observations were
collected from the roof of a five-stored building, near Versosva, West Andheri, Mumbai.
This represents a background urban site, over 3 km inland from the coast, and is likely to
receive both marine and continental aerosols. The site is located sufficiently away from the
transportation or industrial sources, with the traffic roadway about 1 km to the east and
industrial cluster about 3 km to the southeast. However, burning of refuse and biomass
(leaves, garden waste) is an intermittent, local source throughout Mumbai, especially at
nighttime in winter (December–January).
The daily mean air temperature and relative humidity during the pre-Holi, Holi, and
post-Holi periods over the experimental site are plotted in Fig. 2. Temperature was in the
range of 28.5–30° C, and the relative humidity (RH) varied from a low of 54 % to a high of
about 70 %. The variations in relative humidity play an important role in the coagulation
and growth processes of aerosol particles, while the temperature variations influence the
aerosol size distribution. Higher humidity values also favor the gas-to-particle conversion
(secondary aerosols) process, and thereby, they affect the number density. The daily
average higher temperatures might lead several chemical reactions and cause production of
the most of the aerosols in the Aitken and accumulation mode.
4 Experimental setup, principle of operation, and analysis of data
We used two compact, online, multi-wavelength solar radiometers (MICROTOPS-II,
manufactured by M/s Solar Light Co., USA) in the present experiment. These instruments
yield instantaneous estimates of aerosol and gaseous optical depths (extinction) as opposed
to conventional ones (Devara et al. 2001). One of these radiometers (sun photometer)
provides height-integrated AOD at six wavelengths covering from UV to NIR and hence
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Experimental days
Temperature
(°C)
Temperature (°C)
Relative
Humidity
(%)
R. H (%)
Fig. 2 Time variation of
surface-level temperature and
humidity on experimental days
Nat Hazards
123
5. the size distribution of aerosols, and the other radiometer (ozone and perceptible water
content monitor) determines the total column ozone (using the UV band) and perceptible
water content (using the NIR band) simultaneously. Both the radiometers are mounted on a
single wooden platform which in turn fixed to a tripod for achieving high stability, time
synchronization between observations and easy focusing of radiometers to the sun’s disk.
Each radiometer is equipped with internal barometer/altimeter for monitoring the atmo-
spheric pressure and altitude of the experimental location. The global positioning system
(GPS) receiver provides the geographical coordinates of the site, which are used for
estimating the local air mass. The experiments have been conducted on the terrace of the
building to make the radiometers free from nearby topographic targets like tall buildings,
trees, etc. The main parameters of these radiometers are presented in Table 1.
Both the radiometers are tailored with optical collimators accurately aligned with their
fields-of-view (FOVs) and baffles for eliminating internal reflection. Each channel is fitted
with a narrow-band filter and a gallium phosphide (GaP) detector suitable for the particular
wavelength range. A sun target and a pointing assembly are permanently attached to the
optical block and laser aligned to ensure accurate alignment with the optical channels.
When the image of the sun is centered at the cross-hairs of sun target, then all channels are
looking directly at the solar disk. The radiation captured by the collimator and band-passed
by the filters falls onto the photodiode that produces an electrical output proportional to the
radiant power (irradiance). These outputs measured at each optical filter are amplified and
analog-to-digital converted, and finally stored, together with the time of observation pro-
vided by the built-in master clock, in the memory for further analysis. The LCD on sun
photometer provides instantaneous display of AOD, record number and several other
information like power density, etc., recorded at each wavelength. Similarly, the LCD on
the monitor provides instantaneous display of total column ozone and perceptible water
content together with other parameters such as received solar power density at each filter.
Moreover, these radiometers are equipped with built-in algorithms for computing the
ozone, precipitable water content and AOD from the output of the amplifier recorded for
each filter. The radiometers are operated initially by keeping the cover closed for the
optical blocks (consisting of windows, filters, etc.). During this period, the instrument
stores the background values for all the filters. In the next few seconds, on removing the
cover, it collects a set of over 25 observations for each filter. The average value, thus
obtained for each filter, is used to compute the spectral variation of columnar AOD, ozone,
and perceptible water content instantaneously and is depicted on the display for a quick
Table 1 Main specifications of
the portable, online, aerosol,
ozone, and precipitable water
content monitor
Parameter Value/description
Sun photometer
Filter wavelengths 380, 440, 500, 675, 870, and
1,020 nm (5–10 nm FWHM)
Ozone monitor
305.5, 312.5, and 320 nm
(5 nm FWHM)
Precipitable water
content monitor
940 and 1,020 nm (10 nm FWHM)
Field-of-view 2.5°
Dynamic range 3 9 104
Data storage 800 records
Nat Hazards
123
6. look and stored in the memory. The ozone monitor used in the present experiment utilizes
this relationship to derive the total ozone column (the equivalent thickness of pure ozone
layer at standard temperature and pressure) from the measurements of two wavelengths in
the UV region (305.5 and 320 nm). The measurement at additional third wavelength
(312.5 nm) enables correction for particulate scattering and stray light. The columnar
precipitable water content is determined based on the measurements at 940 nm (H2O
absorption peak) and at 1,020 nm (no absorption by water content). The AOD at 1,020 nm
is also calculated based on the extra-terrestrial radiation at that wavelength, corrected for
sun–earth distance, and the ground-level measurements of the radiation at 1,020 nm. This
optical depth at NIR in conjunction with those from the sun photometer at UV and V
regions is utilized to retrieve columnar aerosol size distribution by applying the constrained
linear inversion method (King et al. 1978; King 1982). This method for retrieving the
aerosol size distribution from AOD data has been carried out mainly in two steps. The first
step is for finding out the optimum particle radius range. Having found this, the next step is
for finding out the number concentration [dNc(r)/dlog r] at these radii and also for finding
out a factor Rei
2
that monitors the deviations between the observed and back-calculated
optical depth for a number of iterations. The size distribution corresponds to the iteration
for which the minimum Rei
2
value is considered as the best. The error involved in such
method is less than ±10%. The observed ASDs exhibit a power-law distribution with
different exponents changing at an intermediate size. Hence, this modified Junge power-
law distribution can be approximated by combining the distribution factors with different
components with a switching radius. These exponents and switching radius can be
determined by fitting the size distribution function to the inverted mean size at each step.
More details of the exact procedure can be found in Pandithurai et al. (1997).
5 Results and discussion
5.1 AOD during Holi
The daily mean aerosol optical depth (AOD), estimated for the entire Holi campaign
period, is displayed in Fig. 3. The standard error of the mean aerosol optical depth,
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Experimental days
Aerosol
optical
depth
AOD 380 nm
AOD 440 nm
AOD 500 nm
AOD 675 nm
AOD 870 nm
AOD 1020 nm
Fig. 3 Day-to-day variation of
wavelength dependency of
aerosol optical depth on
experimental days. The Holi
festival period is indicated with a
dashed circle
Nat Hazards
123
7. represented by the vertical bar on each day, is a measure of the scatter of individual optical
depth that has been used to obtain the diurnal averages. The plot shows significant day-to-
day variations of AOD and its dependence on wavelength. The daily mean AOD values at
380, 440, 500, 675, 870, 1,020 nm indicate maximum (more than 0.85) during the Holi
day. These variations in spectral dependence are found to have influence on the derived
aerosol size distributions which are explained in the forthcoming section. This increase is
largely due to biomass-burning and smearing of some colors (in both dry and wet form)
such as red and royal pink (mercury), golden powder (lead, mercury, and cadmium), and
metallic green powder (lead and cadmium) during the Holi festival. It is also interesting to
note a decrease in AOD before and after the Holi period due to the dust-free clean air
condition due to scavenging and wet removal processes during this campaign. AODs were
initially in the range of 0.4–0.5 up to February 28, 2010, but due to the Holi affect, it
increased to 0.85, and thereafter, AOD slowly decreased to the initial value on completion
of the festival on March 3, 2010 onward.
The spectral dependence of aerosol optical depth is typically approximated using
Angstrom’s formula that proposes that extinction of solar radiation by aerosols is a con-
tinuous function of wavelength, without selective bands or lines for scattering or absorp-
tion. Thus, the Angstrom turbidity formula is given as
s ¼ b ka
ð1Þ
where s is the optical depth, k is the wavelength, b is the turbidity coefficient, and a is the
wavelength coefficient (Angstrom 1961). Cachorro et al. (2000) showed that Angstrom
formula provides a good spectral representation of atmospheric aerosol attenuation. From
Eq. 1, b known to vary from 0 to 0.5 or even higher is an index representing the amount of
aerosols present in the atmosphere in the vertical direction. This parameter characterizes
the spectral features of aerosols and it relates to the size of the particles (Shifrin 1995).
Large values of a indicate a relatively high ratio of smaller to larger particles. It is expected
that when the aerosol particles are very small of the order of air molecules, a should
approach 4 and it should approach 0 for very large particles (Holben et al. 2001; Pinker
et al. 2001). The Angstrom exponents in the present study have been computed using the
AODs measured at all the six wavelengths (380, 440, 500, 675, 870, 1,020 nm) of the
radiometer. The mean wavelength exponent (a380-1,020 nm), thus obtained, for the exper-
imental site was 0.671 ± 0.334 as shown in Fig. 4. This parameter was very low (0.2) on
2
4
-
F
e
b
-
1
0
2
5
-
F
e
b
-
1
0
2
6
-
F
e
b
-
1
0
2
7
-
F
e
b
-
1
0
2
8
-
F
e
b
-
1
0
1
-
M
a
r
-
1
0
2
-
M
a
r
-
1
0
3
-
M
a
r
-
1
0
-
-
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
Experimental days
Beta
Alpha
Alpha
Beta
Fig. 4 Day-to-day variation of
Angstrom parameters (Alpha and
Beta) during the study period
Nat Hazards
123
8. and February 24 and 25, 2010, which indicates the presence of coarse-mode particle, but it
increased to 0.6 due to anthropogenic activity and it reached to very high around 1.0 due to
Holi effect. Aerosols in the nucleation size range of 0.01–0.1 lm, undergo condensational
growth or coagulate to form bigger particles, and contribute to accumulation mode
(0.1–1 lm). The precursor gases for the formation of particles in the smaller size range
come mostly from the continents, such as sulfur dioxide, which through oxidation and
condensation get transformed into sulfate aerosol and get transported over long distances in
the marine atmosphere. Such particles are found in abundance near the coastal regions (Qiu
1998). The slightly larger size aerosols in the accumulation mode are relatively longer
lived when compared to the smaller size aerosols, and they also can get dispersed over
longer distances. The larger particles dominating the Indian Ocean region indicate that they
could be mainly sea-spray particles, but the contribution from the windblown mineral dust
from the surrounding continents cannot be ruled out. The mean turbidity parameter or the
Angstrom coefficient b which represents the total aerosol loading in the atmosphere over
the coastal site is found to be 0.10. The mean b values over coastal site, for the month of
February and March 2010, are estimated to be about 0.318 ± 0.114 (Fig 4). The loading is
low (*0.15) during initial period of the campaign (February 25, 2010), but loading sud-
denly increased to higher value on March 1, 2010 (0.55), March 2, 2010 (0.66), and again
decreased on March 3, 2010 (0.26).
5.2 Comparison with MODIS satellite observations
In the comparison of sun photometer- and MODIS-derived AOD at the experimental site,
we need to maintain the time difference between MODIS overpass and the ground-based
AOD measurement as minimum as possible. In order to maintain the spatial coherence
better, we included MODIS data only when the distance from the center of MODIS pixel to
the experimental station was less than 0.2°, both in latitude and in longitude. Figure 5
depicts the comparison between MODIS and MICROTOPS measurements at 500 nm. The
data period covered is from February 24 to March 3, 2010. The correspondence is very
2
4
-
F
e
b
-
1
0
2
5
-
F
e
b
-
1
0
2
6
-
F
e
b
-
1
0
2
7
-
F
e
b
-
1
0
2
8
-
F
e
b
-
1
0
1
-
M
a
r
-
1
0
2
-
M
a
r
-
1
0
3
-
M
a
r
-
1
0
-
-
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Experimental days
AOD
at
550
nm
(MODIS)
AOD
at
550
nm
(MICROTOPS)
AOD at 550 nm (MICROTOPS)
AOD at 550 nm (MODIS)
R = 0.86
Fig. 5 Comparison between aerosol optical depths observed at characteristic wavelength of 550 nm
between MICROTOPS and MODIS during the study period
Nat Hazards
123
9. good with a linear correlation coefficient of 0.88, which is partly due to the fact that these
periods exhibited a clear range of AOD values, including both very high AOD values and
significantly lower values on some days, when the air masses arrived from outside bio-
mass-burning areas. The linear fit applied between the AODs from MICROTOPS and
MODIS showed correlation of 0.865 ± 0.087 (Fig. 6).
5.3 Short-term variations in aerosol size distribution
Figure 7 displays daily variation of aerosol size distribution (ASD), inverted from the
spectral distribution of AOD following the constrained linear numerical inversion scheme
as suggested by King et al. (1978) and King (1982). Aerosol turbidity shows accumulation
mode type of aerosol during the observation campaign. The columnar ASD, thus evaluated
from the above methodology, for the experimental days is shown in Fig. 7. Most of the
time, either power-law or bimodal distribution was noticed. A bimodal distribution was
observed on February 24, 25, and 27 and March 3, 2010, and power-law distribution was
noticed during the remaining period. The b value is very low and a value is high on
February 28, 2010, indicating the fine mode dominance in the aerosol size distribution
spectrum. This loading, dominated by the fine mode particles, continued to increase for
some time even after the Holi because of their lighter mass.
5.4 Daily mean variations of PWC and ozone
The daily averages of PWC (Fig. 8) varied from 0.85 to 1.6 cm during the campaign
period. At the commencement of the experiment (February 24, 2010), PWC was very low
(*0.85 cm); thereafter, the AOD and PWC almost followed each other, which clearly
signifies the hydrophilic nature of the particles on the eve of Holi festival. This aspect
implies that the higher water content helped the growth of existing particles and also the
formation of new particles, both resulted in higher AOD. The daily mean ozone indicated
somewhat different trend, but in the beginning of the campaign, it was low (*215 DU) but
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
AOD
at
550
nm
(MODIS)
AOD at 550 nm (MICROTOPS)
R=0.867+/- 0.087
N=8
Fig. 6 Correlation between AODs observed from MICROTOPS and MODIS
Nat Hazards
123
10. rose to 260 DU on 1 March and decreased (*250 DB) on the festive day (Fig. 9). This
opposite relationship between AOD and ozone variations on March 2, 2010, clearly hints
the role of heterogeneous chemistry, similar to the result reported in the previous works by
Devara et al. (2001).
10
5
10
7
10
9
10
5
10
7
10
9
10
5
10
7
10
9
10
5
10
7
10
9
10
5
10
7
10
9
10
5
10
7
10
9
10
5
10
7
10
9
0.1 1
0.1 1
0.1 1
0.1 1
0.1 1
0.1 1
0.1 1
0.1 1
10
5
10
7
10
9
24
th
Feb 10
25
th
Feb 10
26
th
Feb 10
27
th
Feb 10
dN
c
/d
(Log
R)
(cm
-2
µ
−1
)
Radius (µm)
28
th
Feb 10
1
st
March 10
2
nd
March 10
3
rd
March 10
Fig. 7 Aerosol size distributions observed on different experimetnal days
2
4
-
F
e
b
-
1
0
2
5
-
F
e
b
-
1
0
2
6
-
F
e
b
-
1
0
2
7
-
F
e
b
-
1
0
2
8
-
F
e
b
-
1
0
1
-
M
a
r
-
1
0
2
-
M
a
r
-
1
0
3
-
M
a
r
-
1
0
-
-
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Experimental days
Precipitable
water
content
(cm)
Fig. 8 Time variation of
precipitable water content on
experimental days
Nat Hazards
123
11. 5.5 Long-range transport of aerosols
Figure 10 shows one-, three-, five-, and seven-day back trajectories [at three characteristic
altitudes of 500 m (red color), 1,500 m (blue color), and 2,000 m (green color)] with
reference to March 3, 2010 (post-Holi day) over the region, obtained from NOAA HY-
SPLIT (National Oceanic and Atmospheric Administration Hybrid Single-Particle
Lagrangian Integrated Trajectory) version 4 model (Draxler and Hess 1998). The plots
clearly display that different air masses (originating mainly from the Arabian Sea and
partly from the Indian subcontinent) influenced the AOD over the observational site. It is
also evident from the figure that in all cases, the higher altitude air masses originate from
Arabian Sea and Indian subcontinent without traveling over longer distance, while at lower
altitudes, air masses travel more distance and affect significantly the trajectory direction on
certain days.
5.6 Surface radiative forcing
The pyranometer-measured global short-wave (SW) flux in the wavelength region between
0.3 and 3.0 lm is correlated with instantaneous AOD at 500 nm after correcting to the air
mass factor (1/l) so as to calculate the radiative forcing (Jayaraman et al. 1998). Nor-
malization of the AOD with l (=cos h) is found to be necessary as the slant air column
length increases with increasing solar zenith angle, h. The observed solar flux represents
the solar flux at the surface, normal to the angle of incidence, with a cone of about 2.5°
around the Sun. The data for solar zenith angles greater than 60° are excluded (to avoid
earth’s curvature effect) and the AOD/l values are restricted to within 0.8. Figure 11
shows daily variation of the surface SW aerosol radiative forcing, which is derived from
the scatter plot of the measured-normalized SW flux with AOD for the experimental days
during the festival eve. A straight line could be fitted to the data with a negative slope
(radiative efficiency) of about 781.701, 318.88, 284.05, 295.795, and 451.477 W/m2
per
unit AOD for February 24, 25, 26, and 28 and March 3, 2010 days, respectively. This
2
4
-
F
e
b
-
1
0
2
5
-
F
e
b
-
1
0
2
6
-
F
e
b
-
1
0
2
7
-
F
e
b
-
1
0
2
8
-
F
e
b
-
1
0
1
-
M
a
r
-
1
0
2
-
M
a
r
-
1
0
3
-
M
a
r
-
1
0
-
-
160
180
200
220
240
260
280
300
Experimental days
Ozone
(DU)
Fig. 9 Day-to-day variation of
columnar ozone during the study
period
Nat Hazards
123
12. implies that for a 0.1 increase in the prescribed columnar AOD, the direct visible solar flux
at surface decreases by about 78.1, 31.8, 28.4, 29.5, and 45.1W/m2
for the above days.
Such a range of forcing values have been reported over the Arabian Sea and higher values
during volcanic episodes in the literature (for example, Suresh Babu et al. 2007; Young
et al. 2012). The greater aerosol forcing at the bottom of the atmosphere on clear-sky days
Fig. 10 1-day (a), 3-day (b), 5-day (c), and 7-day (d) back trajectories at 500 m, 1,500 m, and 2,000 m
levels observed with respect to March 3, 2010
Nat Hazards
123
13. over a coastal site during the Holi festival, as expected, could be due to higher aerosol load,
which attenuates the surface-reaching solar irradiance.
6 Summary and conclusions
The atmosphere over the coastal site (West Andheri, Mumbai) is found to be relatively
clean from aerosols before the Holi period (between March 1 and 2, 2010). During that
time, biomass-burning and toxic aerosols from Indian subcontinent are noticed to transport
to the experimental site and to the other parts of India. The present paper reports a compact
study, exploiting AOD measurements on such occasions. Moreover, concurrent MODIS
satellite AOD measurements obtained at the above site were also used for monitoring the
spatial and temporal evolution of particulate matter spread from these fires. In the first part
of our study, we compared MICROTOPS and MODIS AOD at coastal site, West Andheri.
In this comparison, we found a very good correlation, although it is emphasized that this
eight-day period (from February 24 to March 3, 2010) is rather short to be compared
against previous MODIS validation studies with longer-term data sets. However, the
present results clearly indicate the potential MODIS AOD data offer in AOD monitoring.
During this event of biomass-burning aerosols, clear AOD variability was apparent in the
measurements. This large range in AOD obviously partly explains the high correlation
(0.86) between MODIS and MICROTOPS measurements. The day-to-day AOD variability
was also investigated using HYSPLIT generated trajectories. The backward trajectories up
to seven days (in steps of two days) from the post-festive day were used to assess the origin
of the air masses arriving at experimental site. The air mass mostly from the Arabian Sea
and Indian subcontinent contributes to the aerosols over the experimental sire. The surface
aerosol radiative forcing over the observational (coastal) site showed variation between
28.4 and 78.1 W/m2
, which is consistent with the results reported by earlier investigators.
24-Feb-10
25-Feb-10
26-Feb-10
28-Feb-10
3-March-10
20
30
40
50
60
70
80
Aerosol
radiative
forcing
(wm
-2
)
Experimental days
Surface radiative forcing
Fig. 11 Day-to-day variation of aerosol surface radiative forcing during the study period
Nat Hazards
123
14. Acknowledgments This work was supported by the ISRO-SAC, OCEAN SAT-II project. The authors are
grateful to the Editor and anonymous Reviewers for their critical comments and valuable suggestions.
Authors are thankful to Latha Shenoy of the Central Institute for Fisheries and Education (CIFE), West
Andheri; and DRDO, Mumbai, for providing infrastructure support for observations. Thanks are also due to
Director, IITM, for infrastructure support. The authors gratefully acknowledge the NOAA Air Resources
Laboratory (ARL) for providing the HYSPLIT transport and dispersion model and/or READY website
(http://www.arl.noaa.gov/ready.html). We are thankful to GES-DISC DAAC On-line Visualization and
Analysis System: Web-based interface for the visualization and analysis of the MODIS data
(http://g0dup05u.ecs.nasa.gov/Giovanni/).
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