The aim of this work is to present the recent advances in high spatial resolution profiling of aerosols with a short-range multi-static elastic lidar system. Our results demonstrate the feasibility of robust lidar mea...
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The Japanese mission GCOM-C launched in 2017 loads only SGLI imager. SGLI is multi-spectral sensor including near-UV and two polarization channels. This work enhanced the advantages of SGLI feature in aerosol remote s...
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ISBN:
(数字)9781728163741
ISBN:
(纸本)9781728163758
The Japanese mission GCOM-C launched in 2017 loads only SGLI imager. SGLI is multi-spectral sensor including near-UV and two polarization channels. This work enhanced the advantages of SGLI feature in aerosol remote sensing. It was shown that the near-UV data not only detected absorbing aerosols such as biomass burning aerosols (BBA) or mineral dust (DUST), but was also used to distinguish between BBA and DUST with short-IR data. For leading issues such as aerosols above clouds, the detection of optically thick clouds was challenged in a similar manner to aerosol classification as well as utilization of polarization measurements. As a result, some scenes concerned with DUST or BBA above water clouds were practically detected.
In the paper the outcomes of the analysis of acoustic energy absorption in aerosols have been presented. Every, even the smallest particle of aerosol constitutes some kind of an obstacle, a barrier, for an acoustic wa...
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In the last three last decades air pollution level has been increased significantly especially in the northern parts of India with Delhi being the most polluted city. Population growth, energy demand, industrial growt...
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ISBN:
(数字)9781728163741
ISBN:
(纸本)9781728163758
In the last three last decades air pollution level has been increased significantly especially in the northern parts of India with Delhi being the most polluted city. Population growth, energy demand, industrial growth, increased crop burning, increased traffic density and coal burning have affected the air quality of Delhi and surrounding areas upto a great extent. In the present paper, we have used MODIS Terra and Aqua data to study the annual and seasonal variations of Aerosol Optical Depth (AOD) and Angstrom Exponent (AE) and also tried to identify the sources of pollution based on AOD and AE. A wide variation in AOD, (range 0.07 to 3.49) and AE, (range 0-1.8) is observed during 2000-2019 over Delhi and surrounding regions. This shows very poor air quality and highly polluted atmospheric. Different aerosol types are found to be season dependent based on the detailed analysis of AOD and AE retrieved from satellite data during the period 2000-2019. The present analysis shows dominance of anthropogenic aerosols (AA) during winter whereas biomass burning (BB) during post monsoon seasons. During pre monsoon season pollutant continental (PC) and mostly dust (MD) were observed for many days as air mass travel from Thar Desert, Middle East and Arabia with the westerly winds. In the recent decade, clean days in Delhi are reduced significantly.
The processes of aerosols diffusion for turbulent flows in channels of industrial ventilation systems are considered. To describe the motion of discrete spherical particle in homogeneous turbulent flow, we apply the B...
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ISBN:
(数字)9781728169514
ISBN:
(纸本)9781728169521
The processes of aerosols diffusion for turbulent flows in channels of industrial ventilation systems are considered. To describe the motion of discrete spherical particle in homogeneous turbulent flow, we apply the Basset equation. To analyze the characteristics of the turbulent flow, the time Lagrange correlation coefficients and the Lagrange functions of the energy spectrum are used. The time correlation coefficient of the main flow is approximated by the exponential dependence. The process of aerosols diffusion is conditionally divided into three stages: induction, transition and basic. In the induction period, the particles are accelerated by the Stokes forces from zero velocity to the main flow velocity, while the diffusion process is practically absent. In the transition period, the diffusion process occurs at variable diffusion coefficient. After the initial stages, the basic diffusion process of aerosol particles begins at constant diffusion coefficient, which can be investigated by known methods. The time characteristics of the initial periods in aerosols diffusion were estimated. The approximate expression was obtained for the diffusion coefficient of aerosol particles in the transition period. It is recommended when placing the concentration control means both the length of the concentration equalization path and the distance traveled by the particles during the induction and transient periods should be considered. When the length of the ventilation channel is relatively small, or the concentration control means are installed at sufficiently small distance from the source of emissions, the results of the control should be corrected.
This dissertation investigated the impacts of natural and anthropogenic aerosols on Atlantic tropical cyclones by combining observational analyses and numerical modeling. The objectives of the research were to assess ...
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This dissertation investigated the impacts of natural and anthropogenic aerosols on Atlantic tropical cyclones by combining observational analyses and numerical modeling. The objectives of the research were to assess the impacts of anthropogenic aerosols on Hurricane Harvey (2017) and Saharan dust on two hurricanes, Danielle and Earl (2010). Hurricane Harvey made landfall near Rockport, Texas, as a category 4 hurricane on 26 August. Harvey produced heavy rainfall of about 555 mm in the Houston urban area during 25-27 August. Ground- and satellite-based lightning and ground-based radar reflectivity measurements were analyzed, showing unusually intense lightning (over 0.23 million strikes) and radar reflectivity in the Houston region during 26-27 August. The effects of anthropogenic aerosols on precipitation and lightning during Harvey was investigated using a Cloud-Resolving Weather and Research Forecasting (CR-WRF) model. The ensemble simulations spanned from 25 to 28 August. The simulations show that anthropogenic aerosols increase precipitation and lightning in Houston by a factor of 2-3, unraveling the dominant factor of regulating the energetics and flooding during this extreme weather event. Combined measurements and numerical model simulations were made to show fundamentally altered cloud microphysical and thermodynamic processes of Hurricane Harvey by anthropogenic aerosols. The second part of this dissertation evaluated the impacts of Saharan dust during Hurricanes Danielle and Earl (2010). Hurricanes Danielle and Earl both originated from the West African coast and developed under similar large-scale dynamic conditions and coexisted in the different stages of their life cycles and were subjected to the intrusion of Saharan dust. The CR-WRF was used in conjunction with an aerosol-aware two-moment bulk microphysics scheme, accounting for dust as ice nucleating particles (INPs) and dust radiative forcing. The model simulations reveal that the radiative effect
A tracheostomy performed on patients infected with SARS CoV-2 is one of the procedures with the highest risks of aerosolization. Safety recommendations for carrying out this procedure are not suitable for implementati...
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A good understanding of trends, variations, and causes of atmospheric aerosols is vital to quantifying the role of air quality in climate change and health concerns and for informing relevant regulatory policies. This...
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A good understanding of trends, variations, and causes of atmospheric aerosols is vital to quantifying the role of air quality in climate change and health concerns and for informing relevant regulatory policies. This thesis presents four projects that exploit a range of observational data and modeling tools to characterize and interpret aerosol dynamics and its potential *** econometric model is implemented to identify aerosol variations, predictions, and the driving forces using six sites spreading across North America and East Asia during 2003–2015. Regional differences caused by impacts of climatology and land cover types are observed. Statistical validation of time series ARIMA models indicates the applicability and feasibility of ARIMA modeling. The reasonably-predicted AOD values could provide reliable estimates to inform better the decision-making for sustainable environmental management and the initiative of reforestation on emission sinks could have potential implications for climate change *** time series analyses and modeling of aerosol variability are further investigated in a spatially continuous framework based on the valuable spatiotemporal dimension of the remote sensing data over the contiguous United States (U.S.) and China. By comparing variations and trends in these two countries, we attribute the large differences to the energy strategies, economic and urban development, and lifestyle activities. Areas most suitable for applying the model for prediction are those with high AOD quality, high completeness of AOD data, low-AOD values, and AOD time series with clear seasonal ***, a geographically weighted regression (GWR) model is employed to estimate PM concentration and analyze its relationships with AOD, meteorological variables, and nighttime light (NTL) data across the Northeastern United States in 2013. Improved GWR model performance is found for the warm season when applying the index that incorporates norm
Influence of pollution on dynamics of deep convection continues to be a controversial topic. Arguably, only carefully designed numerical simulations can clearly separate the impact of aerosols from the effects of mete...
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Influence of pollution on dynamics of deep convection continues to be a controversial topic. Arguably, only carefully designed numerical simulations can clearly separate the impact of aerosols from the effects of meteorological factors that affect moist convection. This paper argues that such a separation is virtually impossible using observations because of the insufficient accuracy of atmospheric measurements and the fundamental nature of the interaction between deep convection and its environment. To support this conjecture, results from numerical simulations are presented that apply modeling methodology previously developed by the author. The simulations consider small modifications, difficult to detect in observations, of the initial sounding, surface fluxes, and large-scale forcing tendencies. All these represent variations of meteorological conditions that affect deep convective dynamics independently of aerosols. The setup follows the case of daytime convective development over land based on observations during the Large-Scale Biosphere- Atmosphere (LBA) field project in Amazonia. The simulated observable macroscopic changes of convection, such as the surface precipitation and upper-tropospheric cloudiness, are similar to or larger than those resulting from changes of cloud condensation nuclei from pristine to polluted conditions studied previously using the same modeling case. Observations from Phase III of the Global Atmospheric Research Program Atlantic Tropical Experiment (GATE) are also used to support the argument concerning the impact of the large-scale forcing. The simulations suggest that the aerosol impacts on dynamics of deep convection cannot be isolated from meteorological effects, at least for the daytime development of unorganized deep convection considered in this study.
The chemical aging of liquid organic aerosols most likely occurs via exothermic heterogeneous chemical reactions on the aerosol's surface. Because of the enthalpy of reactions, the temperature of an aerosol partic...
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The chemical aging of liquid organic aerosols most likely occurs via exothermic heterogeneous chemical reactions on the aerosol's surface. Because of the enthalpy of reactions, the temperature of an aerosol particle during its chemical aging may become greater than the ambient (air) temperature. We attempt to shed light on this aspect of the formation of secondary organic aerosols considering their nucleation and chemical aging as concomitant processes. Using the model of aqueous hydrophilic-hydrophobic organic aerosols in the framework of classical nucleation theory, we evaluate characteristic time scales of the four most important processes involved in this complex phenomenon. Their analysis suggests that the release of the enthalpy of heterogeneous chemical reactions during the chemical aging of organic aerosols may play a significant impeding role in the formation of an ensemble of aqueous secondary organic aerosols via nucleation and hence must be taken into account in atmospheric aerosol and global climate models.
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