Investigation of Aerosol Climatology, Optical Characteristics and Variability over Egypt Based on Satellite Observations and In-Situ Measurements

Egypt experiences high rates of air pollution, which is a major threat to human health and the eco-environment and therefore needs to be tackled by defining major causes to hinder or mitigate their impacts. The major driving forces of air pollution are either of local and/or regional origin. In addition, seasonal aerosols may be natural, such as dust particles transported from the western desert, or anthropogenic aerosols which are transported from industrial areas and smoke particles from seasonal biomass burning. Monitoring the optical properties of aerosols and their pattern in the atmosphere on a daily basis requires a robust source of information and professional analytical tools. This research explored the potential of using time series of Moderate Resolution Imaging Spectroradiometer (MODIS) and Aerosol Robotic Network (AERONET) data to comprehensively investigate the aerosol optical depth (AOD) and variability for the period 2012–2018 on a daily basis. The data show that spring, summer and autumn seasons experienced the highest anomaly originating from regional and national sources. The high AOD in spring associated with a low Ångström exponent (AE) indicates the presence of coarse particles which naturally originate from desert dust or sea spray. In contrast, the high AE in summer and autumn demonstrated the dominance of fine anthropogenic aerosols such as smoke particles from local biomass burning. The observation of a high number of fire incidents over Egypt in October and November 2018, during the months of rice crop harvesting, showed that these incidents contribute to the presence of autumn aerosols across the country. In-situ measurements of Particulate Matter (PM10) from local stations from an environmental based network as well as the AERONET AOD were used to validate the MODIS AOD, providing a high correlation coefficient of r = 0.73.

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Using the OMI Aerosol Index and Absorption Aerosol Optical Depth to evaluate the NASA MERRA Aerosol Reanalysis

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-32177-2014 ◽

2014 ◽

Vol 14 (23) ◽

pp. 32177-32231 ◽

Cited By ~ 6

Author(s):

V. Buchard ◽

A. M. da Silva ◽

P. R. Colarco ◽

A. Darmenov ◽

C. A. Randles ◽

...

Keyword(s):

Optical Properties ◽

Aerosol Optical Depth ◽

Optical Depth ◽

Biomass Burning ◽

Saharan Dust ◽

Aerosol Layer ◽

Anthropogenic Aerosols ◽

Aerosol Absorption ◽

Modis Aod ◽

Aerosol Index

Abstract. A radiative transfer interface has been developed to simulate the UV Aerosol Index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) aerosol assimilated fields. The purpose of this work is to use the AI and Aerosol Absorption Optical Depth (AAOD) derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications Aerosol Reanalysis (MERRAero). MERRAero is based on a version of the GEOS-5 model that is radiatively coupled to the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) aerosol module and includes assimilation of Aerosol Optical Depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Since AI is dependent on aerosol concentration, optical properties and altitude of the aerosol layer, we make use of complementary observations to fully diagnose the model, including AOD from the Multi-angle Imaging SpectroRadiometer (MISR), aerosol retrievals from the Aerosol Robotic Network (AERONET) and attenuated backscatter coefficients from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission to ascertain potential misplacement of plume height by the model. By sampling dust, biomass burning and pollution events in 2007 we have compared model produced AI and AAOD with the corresponding OMI products, identifying regions where the model representation of absorbing aerosols was deficient. As a result of this study over the Saharan dust region, we have obtained a new set of dust aerosol optical properties that retains consistency with the MODIS AOD data that were assimilated, while resulting in better agreement with aerosol absorption measurements from OMI. The analysis conducted over the South African and South American biomass burning regions indicates that revising the spectrally-dependent aerosol absorption properties in the near-UV region improves the modeled-observed AI comparisons. Finally, during a period where the Asian region was mainly dominated by anthropogenic aerosols, we have performed a qualitative analysis in which the specification of anthropogenic emissions in GEOS-5 is adjusted to provide insight into discrepancies observed in AI comparisons.

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Wildfire Smoke Particle Properties and Evolution, From Space-Based Multi-Angle Imaging II: The Williams Flats Fire during the FIREX-AQ Campaign

Remote Sensing ◽

10.3390/rs12223823 ◽

2020 ◽

Vol 12 (22) ◽

pp. 3823

Author(s):

Katherine T. Junghenn Noyes ◽

Ralph A. Kahn ◽

James A. Limbacher ◽

Zhanqing Li ◽

Marta A. Fenn ◽

...

Keyword(s):

Particle Size ◽

Biomass Burning ◽

In Situ Measurements ◽

Statistical Characterization ◽

Smoke Particle ◽

Particle Properties ◽

In Situ Data ◽

Particle Property ◽

Aircraft Data

Although the characteristics of biomass burning events and the ambient ecosystem determine emitted smoke composition, the conditions that modulate the partitioning of black carbon (BC) and brown carbon (BrC) formation are not well understood, nor are the spatial or temporal frequency of factors driving smoke particle evolution, such as hydration, coagulation, and oxidation, all of which impact smoke radiative forcing. In situ data from surface observation sites and aircraft field campaigns offer deep insight into the optical, chemical, and microphysical traits of biomass burning (BB) smoke aerosols, such as single scattering albedo (SSA) and size distribution, but cannot by themselves provide robust statistical characterization of both emitted and evolved particles. Data from the NASA Earth Observing System’s Multi-Angle Imaging SpectroRadiometer (MISR) instrument can provide at least a partial picture of BB particle properties and their evolution downwind, once properly validated. Here we use in situ data from the joint NOAA/NASA 2019 Fire Influence on Regional to Global Environments Experiment-Air Quality (FIREX-AQ) field campaign to assess the strengths and limitations of MISR-derived constraints on particle size, shape, light-absorption, and its spectral slope, as well as plume height and associated wind vectors. Based on the satellite observations, we also offer inferences about aging mechanisms effecting downwind particle evolution, such as gravitational settling, oxidation, secondary particle formation, and the combination of particle aggregation and condensational growth. This work builds upon our previous study, adding confidence to our interpretation of the remote-sensing data based on an expanded suite of in situ measurements for validation. The satellite and in situ measurements offer similar characterizations of particle property evolution as a function of smoke age for the 06 August Williams Flats Fire, and most of the key differences in particle size and absorption can be attributed to differences in sampling and changes in the plume geometry between sampling times. Whereas the aircraft data provide validation for the MISR retrievals, the satellite data offer a spatially continuous mapping of particle properties over the plume, which helps identify trends in particle property downwind evolution that are ambiguous in the sparsely sampled aircraft transects. The MISR data record is more than two decades long, offering future opportunities to study regional wildfire plume behavior statistically, where aircraft data are limited or entirely lacking.

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Simulating Secondary Inorganic Aerosols using the chemistry transport model MOCAGE version R2.15.0

Geoscientific Model Development Discussions ◽

10.5194/gmdd-8-3593-2015 ◽

2015 ◽

Vol 8 (4) ◽

pp. 3593-3651 ◽

Cited By ~ 1

Author(s):

J. Guth ◽

B. Josse ◽

V. Marécal ◽

M. Joly

Keyword(s):

North America ◽

Transport Model ◽

Regional Scale ◽

In Situ Measurements ◽

Aerosol Composition ◽

Chemistry Transport Model ◽

Inorganic Aerosols ◽

Modis Aod ◽

Inorganic Aerosol

Abstract. In this study we develop a Secondary Inorganic Aerosol (SIA) module for the chemistry transport model MOCAGE developed at CNRM. Based on the thermodynamic equilibrium module ISORROPIA II, the new version of the model is evaluated both at the global scale and at the regional scale. The results show high concentrations of secondary inorganic aerosols in the most polluted regions being Europe, Asia and the eastern part of North America. Asia shows higher sulfate concentrations than other regions thanks to emissions reduction in Europe and North America. Using two simulations, one with and the other without secondary inorganic aerosol formation, the model global outputs are compared to previous studies, to MODIS AOD retrievals, and also to in situ measurements from the HTAP database. The model shows a better agreement in all geographical regions with MODIS AOD retrievals when introducing SIA. It also provides a good statistical agreement with in situ measurements of secondary inorganic aerosol composition: sulfate, nitrate and ammonium. In addition, the simulation with SIA gives generally a better agreement for secondary inorganic aerosols precursors (nitric acid, sulfur dioxide, ammonia) in particular with a reduction of the Modified Normalised Mean Bias (MNMB). At the regional scale, over Europe, the model simulation with SIA are compared to the in situ measurements from the EMEP database and shows a good agreement with secondary inorganic aerosol composition. The results at the regional scale are consistent with those obtained with the global simulations. The AIRBASE database was used to compare the model to regulated air quality pollutants being particulate matter, ozone and nitrogen dioxide concentrations. The introduction of the SIA in MOCAGE provides a reduction of the PM2.5 MNMB of 0.44 on a yearly basis and even 0.52 on a three spring months period (March, April, May) when SIA are maximum.

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Aerosol classification by airborne high spectral resolution lidar observations

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-2487-2013 ◽

2013 ◽

Vol 13 (5) ◽

pp. 2487-2505 ◽

Cited By ~ 124

Author(s):

S. Groß ◽

M. Esselborn ◽

B. Weinzierl ◽

M. Wirth ◽

A. Fix ◽

...

Keyword(s):

Biomass Burning ◽

Spectral Resolution ◽

Classification Scheme ◽

In Situ Measurements ◽

High Spectral Resolution ◽

Data Set ◽

Aerosol Classification ◽

High Spectral Resolution Lidar ◽

Aerosol Types

Abstract. During four aircraft field experiments with the DLR research aircraft Falcon in 1998 (LACE), 2006 (SAMUM-1) and 2008 (SAMUM-2 and EUCAARI), airborne High Spectral Resolution Lidar (HSRL) and in situ measurements of aerosol microphysical and optical properties were performed. Altogether, the properties of six different aerosol types and aerosol mixtures – Saharan mineral dust, Saharan dust mixtures, Canadian biomass burning aerosol, African biomass burning mixture, anthropogenic pollution aerosol, and marine aerosol have been studied. On the basis of this extensive HSRL data set, we present an aerosol classification scheme which is also capable to identify mixtures of different aerosol types. We calculated mixing lines that allowed us to determine the contributing aerosol types. The aerosol classification scheme was supported by backward trajectory analysis and validated with in-situ measurements. Our results demonstrate that the developed aerosol mask is capable to identify complex stratifications with different aerosol types throughout the atmosphere.

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Remote sensed and in situ constraints on processes affecting tropical tropospheric ozone

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-815-2007 ◽

2007 ◽

Vol 7 (3) ◽

pp. 815-838 ◽

Cited By ~ 136

Author(s):

B. Sauvage ◽

R. V. Martin ◽

A. van Donkelaar ◽

X. Liu ◽

K. Chance ◽

...

Keyword(s):

Biomass Burning ◽

Tropospheric Ozone ◽

In Situ Measurements ◽

Model Bias ◽

Top Down ◽

Upper Troposphere ◽

In Situ Observations ◽

Tropospheric O3 ◽

Bias Versus

Abstract. We use a global chemical transport model (GEOS-Chem) to evaluate the consistency of satellite measurements of lightning flashes and ozone precursors with in situ measurements of tropical tropospheric ozone. The measurements are tropospheric O3, NO2, and HCHO columns from the GOME satellite instrument, lightning flashes from the OTD and LIS satellite instruments, profiles of O3, CO, and relative humidity from the MOZAIC aircraft program, and profiles of O3 from the SHADOZ ozonesonde network. We interpret these multiple data sources with our model to better understand what controls tropical tropospheric ozone. Tropical tropospheric ozone is mainly affected by lightning NOx and convection in the upper troposphere and by surface emissions in the lower troposphere. Scaling the spatial distribution of lightning in the model to the observed flashes improves the simulation of O3 in the upper troposphere by 5–20 ppbv versus in situ observations and by 1–4 Dobson Units versus GOME retrievals of tropospheric O3 columns. A lightning source strength of 6±2 Tg N/yr best represents in situ observations from aircraft and ozonesonde. Tropospheric NO2 and HCHO columns from GOME are applied to provide top-down constraints on emission inventories of NOx (biomass burning and soils) and VOCs (biomass burning). The top-down biomass burning inventory is larger than the bottom-up inventory by a factor of 2 for HCHO and alkenes, and by a factor of 2.6 for NOx over northern equatorial Africa. These emissions increase lower tropospheric O3 by 5–20 ppbv, improving the simulation versus aircraft observations, and by 4 Dobson Units versus GOME observations of tropospheric O3 columns. Emission factors in the a posteriori inventory are more consistent with a recent compilation from in situ measurements. The ozone simulation using two different dynamical schemes (GEOS-3 and GEOS-4) is evaluated versus observations; GEOS-4 better represents O3 observations by 5–15 ppbv, reflecting enhanced convective detrainment in the upper troposphere. Heterogeneous uptake of HNO3 on aerosols reduces simulated O3 by 5–7 ppbv, reducing a model bias versus in situ observations over and downwind of deserts. Exclusion of HO2 uptake on aerosols increases O3 by 5 ppbv in biomass burning regions, reducing a model bias versus MOZAIC aircraft measurements.

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Estimation of Biomass Burning Influence on Air Pollution around Beijing from an Aerosol Retrieval Model

The Scientific World JOURNAL ◽

10.1155/2014/649648 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 12

Author(s):

Sonoyo Mukai ◽

Masayoshi Yasumoto ◽

Makiko Nakata

Keyword(s):

Air Pollution ◽

Radiative Transfer ◽

Biomass Burning ◽

Atmospheric Aerosols ◽

Transfer Problem ◽

Carbonaceous Aerosols ◽

Retrieval Model ◽

Anthropogenic Aerosols ◽

Radiative Transfer Problem ◽

Aerosol Retrieval

We investigate heavy haze episodes (with dense concentrations of atmospheric aerosols) occurring around Beijing in June, when serious air pollution was detected by both satellite and ground measurements. Aerosol retrieval is achieved by radiative transfer simulation in an Earth atmosphere model. We solve the radiative transfer problem in the case of haze episodes by successive order of scattering. We conclude that air pollution around Beijing in June is mainly due to increased emissions of anthropogenic aerosols and that carbonaceous aerosols from agriculture biomass burning in Southeast Asia also contribute to pollution.

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Multiscale observations of NH3 around Toronto, Canada

10.5194/egusphere-egu2020-10486 ◽

2020 ◽

Author(s):

Shoma Yamanouchi ◽

Camille Viatte ◽

Kimberly Strong ◽

Dylan B. A. Jones ◽

Cathy Clerbaux ◽

...

Keyword(s):

Case Studies ◽

Biomass Burning ◽

Grid Point ◽

Fine Particulate Matter ◽

Regional Scale ◽

Model Performance ◽

In Situ Measurements ◽

Coefficient Of Determination ◽

Predictive Capacity

<div> <div> <div> <p>Ammonia (NH<sub>3</sub>) is a major source of nitrates in the atmosphere, and a major source of fine particulate matter. As such, there have been increasing efforts to monitor NH<sub>3</sub>. This study examines long-term measurements of NH<sub>3</sub> around Toronto, Canada, derived from three multiscale datasets: 16 years of total column measurements using ground-based Fourier transform infrared (FTIR) spectroscopy, three years of surface in-situ measurements, and ten years of total columns from the Infrared Atmospheric Sounding Interferometer (IASI) sensor onboard the Metop satellites. These datasets were used to quantify NH<sub>3</sub> temporal variabilities (trends, inter-annual, seasonal) over Toronto to assess the observational footprint of the FTIR measurements, and two case studies of pollution events due to transport of biomass burning plumes.</p> <p>All three timeseries showed increasing trends in NH<sub>3</sub> over Toronto: 3.34 &#177; 0.44 %/year from 2002 to 2018 in the FTIR columns, 8.88 &#177; 2.49 %/year from 2013 to 2017 in the surface in-situ data, and 8.78 &#177; 0.84 %/year from 2008 to 2018 in the IASI columns. To assess the observational footprint of the FTIR NH<sub>3</sub> columns, correlations between the datasets were examined. The best correlation between FTIR and IASI was found for coincidence criterion of &#8804; 50 km and &#8804; 20 minutes, with r = 0.66 and a slope of 0.988 &#177; 0.058. The FTIR column and in-situ measurements were standardized and correlated, with 24-day averages and monthly averages yielding correlation coefficients of r = 0.72 and r = 0.75, respectively.<br>FTIR and IASI were also compared against the GEOS-Chem model, run at 2&#176; by 2.5&#176; resolution, to assess model performance and investigate correlation of the model output with local column measurements (FTIR) and measurements on a regional scale (IASI). Comparisons on a regional scale (domain spanning from 35&#176;N to 53&#176;N, and 93.75&#176;W to 63.75&#176;W) resulted in r = 0.62, and thus a coefficient of determination, which is indicative of the predictive capacity of the model, of r<sup>2</sup> = 0.38, but comparing a single model grid point against the FTIR resulted in a poorer correlation, with r<sup>2</sup> = 0.26, indicating that a finer spatial resolution is needed to adequately model the variability of NH<sub>3</sub>. This study also examines two case studies of NH<sub>3</sub> enhancements due to biomass burning plumes, in August 2014 and May 2016. In these events, enhancements in both the total columns and surface NH3, were observed.</p> </div> </div> </div>

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Interactive comment on “In situ measurements of desert dust particles above the western Mediterranean Sea with the balloon-borne Light Optical Aerosol Counter/sizer (LOAC) during the ChArMEx campaign of summer 2013” by Jean-Baptiste Renard et al.

10.5194/acp-2017-720-rc2 ◽

2017 ◽

Author(s):

Anonymous

Keyword(s):

Mediterranean Sea ◽

Western Mediterranean ◽

In Situ Measurements ◽

Dust Particles ◽

Desert Dust ◽

Western Mediterranean Sea ◽

Aerosol Counter

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Physical and optical properties of atmospheric aerosol by in-situ and radiometric measurements

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-9-25565-2009 ◽

2009 ◽

Vol 9 (6) ◽

pp. 25565-25597

Author(s):

M. Calvello ◽

F. Esposito ◽

G. Pavese ◽

C. Serio

Keyword(s):

Optical Properties ◽

Atmospheric Aerosols ◽

Saharan Dust ◽

Dust Particles ◽

Rural Site ◽

Size Distributions ◽

Anthropogenic Aerosols ◽

Anthropogenic Aerosol ◽

Observation Methods

Abstract. Physical and optical properties of atmospheric aerosols collected by using a high resolution (1.5 nm) spectroradiometer (spectral range 400–800 nm), a 13 stages Dekati Low Pressure Impactor (size range 30 nm–10 μm), and an AE31 Aethalometer (7 wavelenghts from 370 nm to 950 nm), have been examined in a semi-rural site in Southwest Italy (Tito Scalo, 40°35´ N, 15°41´ E, 750 m a.s.l.). In particular, daily averaged values of AOD and Ångström turbidity parameters from radiometric data together with mass-size distributions from impactor data and Black Carbon (BC) concentrations have been analyzed from May to October 2008. Furthermore, by inverting direct solar radiances, aerosol columnar number and volume size distributions have been obtained for the same period. Comparison of different observation methods, allowed to verify if, and in what conditions, changes in aerosol properties measured at ground are representative of columnar properties variations. Agreement between columnar and in-situ measurements has been obtained in case of anthropogenic aerosol loading, while in case of Saharan dust intrusions some discrepancies have been found when dust particles were located at high layers in the atmosphere (4–8 km) thus affecting columnar properties more than surface ones. For anthropogenic aerosols, a good correlation has been confirmed through the comparison of fine aerosol fraction contribution as measured by radiometer, impactor and aethalometer, suggesting that in this case particles are more homogeneously distributed over the lower layers of atmosphere and columnar aerosol optical properties are dominated by surface measured component.

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