scholarly journals The transport of bioaerosols observed by wideband integrated bioaerosol sensor and coherent Doppler lidar

2021 ◽  
Author(s):  
Dawei Tang ◽  
Tianwen Wei ◽  
Jinlong Yuan ◽  
Haiyun Xia ◽  
Xiankang Dou
Keyword(s):  
Regional Climate ◽  
Potential Method ◽  
Ice Nucleation ◽  
Pollution Monitoring ◽  
Aerosol Transport ◽  
Effective Technique ◽  
Coherent Doppler Lidar ◽  
Wind Lidar ◽  
Physical And Chemical ◽  
The Vertical Distribution

Abstract. Bioaerosols are usually defined as aerosols derived from biological systems such as bacteria, fungi, and viruses. They play an important role in atmospheric physical and chemical processes including ice nucleation and cloud condensation. As such, their dispersion affects not only public health but regional climate as well. Lidar is an effective technique for aerosol detection and pollution monitoring. It is also used to profile the vertical distribution of wind vectors. In this paper, a coherent Doppler wind lidar (CDWL) was deployed for wind and aerosol detection in Hefei, China, from 11 to 20 March in 2020. A wideband integrated bioaerosol sensor (WIBS) was deployed to monitor variations in local fluorescent bioaerosol levels. During observation, three aerosol transport events were captured. The WIBS data show that during these transport events, several types of fluorescent aerosol particles exhibit abnormal increases in either their concentration, number fractions to total particles, or number fractions to whole fluorescent aerosols. These increases are attributed to transported external fluorescent bioaerosols instead of local bioaerosols. Based on the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) backward trajectory model and the characteristics of external aerosols in WIBS, their possible sources, transport paths, and components are discussed. This work proves the influence of external aerosol transport on local high particulate matter (PM) pollution and fluorescent aerosol particle composition. The combination of WIBS and CDWL expands the aerosol monitoring parameters and proves to be a potential method for the real-time monitoring of fluorescent biological aerosol transport events. It contributes to the further understanding of bioaerosol transport.

scholarly journals The electrical self-potential method is a non-intrusive snow-hydrological sensor

2015 ◽  
Vol 9 (4) ◽  
pp. 4437-4457 ◽  
Author(s):  
S. S. Thompson ◽  
B. Kulessa ◽  
R. L. H. Essery ◽  
M. P. Lüthi
Keyword(s):  
Spatial Scales ◽  
Chemical Properties ◽  
Potential Method ◽  
Measurement Procedure ◽  
Theoretical Modelling ◽  
Avalanche Forecasting ◽  
Physical And Chemical ◽  
Self Potential ◽  
Water Contents

Abstract. Our ability to measure, quantify and assimilate hydrological properties and processes of snow in operational models is disproportionally poor compared to the significance of seasonal snowmelt as a global water resource and major risk factor in flood and avalanche forecasting. Encouraged by recent theoretical, modelling and laboratory work, we show here that the diurnal evolution of aerially-distributed self-potential magnitudes closely track those of bulk meltwater fluxes in melting in-situ snowpacks at Rhone and Jungfraujoch glaciers, Switzerland. Numerical modelling infers temporally-evolving liquid water contents in the snowpacks on successive days in close agreement with snow-pit measurements. Muting previous concerns, the governing physical and chemical properties of snow and meltwater became temporally invariant for modelling purposes. Because measurement procedure is straightforward and readily automated for continuous monitoring over significant spatial scales, we conclude that the self-potential geophysical method is a highly-promising non-intrusive snow-hydrological sensor for measurement practice, modelling and operational snow forecasting.

scholarly journals Overview of Ice Nucleating Particles

2017 ◽  
Vol 58 ◽  
pp. 1.1-1.33 ◽  
Author(s):  
Zamin A. Kanji ◽  
Luis A. Ladino ◽  
Heike Wex ◽  
Yvonne Boose ◽  
Monika Burkert-Kohn ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Ice Nucleation ◽  
Ice Crystal ◽  
New Developments ◽  
Particle Properties ◽  
Microphysical Properties ◽  
Range Transport ◽  
Homogeneous Freezing ◽  
Aerosol Aging ◽  
Physical And Chemical

Abstract Ice particle formation in tropospheric clouds significantly changes cloud radiative and microphysical properties. Ice nucleation in the troposphere via homogeneous freezing occurs at temperatures lower than −38°C and relative humidity with respect to ice above 140%. In the absence of these conditions, ice formation can proceed via heterogeneous nucleation aided by aerosol particles known as ice nucleating particles (INPs). In this chapter, new developments in identifying the heterogeneous freezing mechanisms, atmospheric relevance, uncertainties, and unknowns about INPs are described. The change in conventional wisdom regarding the requirements of INPs as new studies discover physical and chemical properties of these particles is explained. INP sources and known reasons for their ice nucleating properties are presented. The need for more studies to systematically identify particle properties that facilitate ice nucleation is highlighted. The atmospheric relevance of long-range transport, aerosol aging, and coating studies (in the laboratory) of INPs are also presented. Possible mechanisms for processes that change the ice nucleating potential of INPs and the corresponding challenges in understanding and applying these in models are discussed. How primary ice nucleation affects total ice crystal number concentrations in clouds and the discrepancy between INP concentrations and ice crystal number concentrations are presented. Finally, limitations of parameterizing INPs and of models in representing known and unknown processes related to heterogeneous ice nucleation processes are discussed.

scholarly journals Condensation and immersion freezing Ice Nucleating Particle measurements at Ny-Ålesund (Svalbard) during 2018: evidence of multiple source contribution

2020 ◽  
Author(s):  
Matteo Rinaldi ◽  
Naruki Hiranuma ◽  
Gianni Santachiara ◽  
Mauro Mazzola ◽  
Karam Mansour ◽  
...  
Keyword(s):  
Regional Climate ◽  
Arctic Region ◽  
Ground Level ◽  
Test System ◽  
Ice Nucleation ◽  
The Arctic ◽  
Activation Temperature ◽  
Back Trajectories ◽  
Local Sources ◽  
Immersion Freezing

Abstract. The current inadequate understanding of ice nucleating particle (INP) sources in the Arctic region affects the uncertainty in global radiative budgets and in regional climate predictions. In this study, we present atmospheric INP concentrations by offline analyses on samples collected at ground level in Ny-Ålesund (Svalbard), in spring and summer 2018. The ice nucleation properties of the samples were characterized by means of two offline instruments: the Dynamic Filter Processing Chamber (DFPC), detecting condensation freezing INPs, and the West Texas Cryogenic Refrigerator Applied to Freezing Test system (WT-CRAFT), measuring INPs by immersion freezing. Both measurements agreed within an order of magnitude although with some notable offset. INP concentration measured by DFPC ranged 33–185 (median 88), 5–107 (50) and 3–66 (20) m−3, for T = −22, −18 and −15 °C, respectively, while at the same activation temperatures WT-CRAFT measured 3–199 (26), 1–34 (6) and 1–4 (2) m−3, with an offset apparently dependent on the INP activation temperature. This observation may indicate a different sensitivity of Arctic INPs to different ice nucleation modes, even though a contribution from measurement and/or sampling uncertainties cannot be ruled out. An increase in the coarse INP fraction was observed from spring to summer, particularly at the warmest temperature (up to ~ 70 % at −15 °C). This suggests a non-negligible contribution from local sources of biogenic aerosol particles. This conclusion is also supported by the INP temperature spectra, showing ice-forming activity at temperatures higher than −15 °C. Contrary to recent works (e.g., INP measurements from Ny-Ålesund in 2012), our results do not show a sharp spring-to-summer increase of the INP concentration, with distinct behaviors for particles active in different temperature ranges. This likely indicates that the inter-annual variability of conditions affecting the INP emission by local sources may be wider than previously considered and suggests a complex interplay between INP sources. This demonstrate the necessity of further data coverage. Analysis of INP concentrations, active site density, low-travelling back-trajectories (

scholarly journals MODELING THE TRANS-ATLANTIC TRANSPORTATION OF SAHARAN DUST

2017 ◽  
Vol 50 (2) ◽  
pp. 1052
Author(s):  
A. Tsikerdekis ◽  
P. Zanis ◽  
L.A. Steiner ◽  
V. Amiridis ◽  
E. Marinou ◽  
...  
Keyword(s):  
Optical Thickness ◽  
Climate Model ◽  
Regional Climate ◽  
Saharan Dust ◽  
Dust Transport ◽  
South Central ◽  
Vertical Distributions ◽  
Dust Loading ◽  
Horizontal And Vertical Distributions ◽  
The Vertical Distribution

In the present study we are simulating the trans-Atlantic transport of dust from Sahara to the South-Central America, using the regional climate model RegCM4 and its online dust scheme, for the year 2007. The simulated horizontal and vertical distributions of the mineral dust optical properties were evaluated against the LIVAS CALIPSO satellite dust product. The Trans-Atlantic dust transport is simulated adequately with RegCM4, but there are some spatial discrepancies. Dust optical thickness is overestimated in the eastern Sahara throughout the year by 0.1-0.2, while near the gulf of Guinea is underestimated during winter and spring. Although RegCM4 dust plume is located southern on winter and spring, it doesn't spatially match the dust optical thickness of LIVAS. In summer and autumn the vertical distribution of dust between 3-4km during the Trans-Atlantic transport is simulated by the model adequately up to 30ºW 40ºW longitude. However, during winter-spring RegCM4 misplaces dust loading into higher altitude. Finally, we discuss some possible reasons and mechanisms that might be responsible for the differences between the model and the observations. 

scholarly journals EFFECTS OF AMELIORATIVE AFFORESTATION ON THE ERODIBILITY FACTOR AND SOIL LOSS IN THE GRDELICA GORGE

2020 ◽  
Vol 1 (28) ◽  
Author(s):  
Aleksandar Baumgertel ◽  
Sara Lukić ◽  
Snežana Belanović Simić ◽  
Predrag Miljković
Keyword(s):  
Soil Loss ◽  
Organic Matter Content ◽  
Potential Method ◽  
Matter Content ◽  
Soil Erodibility ◽  
Chemical Laboratory ◽  
Chemical Soil ◽  
Planting Method ◽  
Physical And Chemical

The paper presents research carried out in the area of Grdelica gorge in 60 years old black pine (Pinusnigra Arnold.) stands. The aim of this study was to determine whether the applied planting method ofameliorative afforestation had an impact on physical and chemical soil properties, soil erodibility andsoil loss. The experimental fields were selected from the afforested areas where soil samples weretaken from fixed depths and then were subjected to physical and chemical laboratory analyses. Thesoil erodibility factor K was calculated using the Wischmeier and Smith formula, whilst, soil loss wasestimated according to Erosion Potential method – EPM by Gavrilović. According to the results of theresearch, in the studied period of 60 years there was a change in the soil physical and chemical properties.There was also a reduction in the soil erodibility factor and soil loss which can be the result ofameliorative afforestation. The afforestation method can affect the reduction of soil losses, while theerodibility factor may be affected indirectly (e.g. by increase in the organic matter content, formingstructural aggregates) not immediately after afforestation, but in a long term period.

Biodegradation and decolorization of textile dyes by bacterial strains: a biological approach for wastewater treatment

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Muhammad Ikram ◽  
Muhammad Zahoor ◽  
Gaber El-Saber Batiha
Keyword(s):  
Textile Industry ◽  
Large Scale ◽  
Short Interval ◽  
Textile Dyes ◽  
Bacterial Strains ◽  
Effective Technique ◽  
Clean Environment ◽  
Biological Methods ◽  
Physical And Chemical ◽  
Control Water

AbstractTextile industry releases large quantities of toxic dyes, which is a threat to public health and needs proper management before their release into environment. Out of the different approaches used these days, biodegradation and bio-decolorization is considered an eco-friendly and effective technique as this involves the use of microbes. This technique has the potential to be used effectively for a wide variety of dyes. In biological methods, mainly bacteria, fungi, and some algae are usually employed to remove or decolorize dyes present in textiles effluents and wastewaters. A number of researchers have used bacterial strains and relevant isolated enzymes successfully to decolorize a number of dyes. In this review article, various biological methods that have been used for the biodegradation and decolorization of textile dyes have been described. The review will also revive the significance of biological methods over other physical and chemical treatment methods that would be helpful in ensuring clean environment if used on large scale. Out of these methods, biodegradation through bacterial strains is considered as the best alternative to control water pollution as the growth rate of bacteria is considerably high as compared to other microorganisms. Thus if used the required biomass needed for biodegradation can be obtained in comparatively short interval of time.

Ice in Clouds Experiment–Layer Clouds. Part II: Testing Characteristics of Heterogeneous Ice Formation in Lee Wave Clouds

2012 ◽  
Vol 69 (3) ◽  
pp. 1066-1079 ◽  
Author(s):  
P. R. Field ◽  
A. J. Heymsfield ◽  
B. J. Shipway ◽  
P. J. DeMott ◽  
K. A. Pratt ◽  
...  
Keyword(s):  
Ice Nucleation ◽  
Ice Formation ◽  
Chemical Characteristics ◽  
Ice Clouds ◽  
Field Campaign ◽  
Temperature Range ◽  
Ice Nuclei ◽  
Lee Wave ◽  
Immersion Freezing ◽  
Physical And Chemical

Abstract Heterogeneous ice nucleation is a source of uncertainty in models that represent ice clouds. The primary goal of the Ice in Clouds Experiment–Layer Clouds (ICE-L) field campaign was to determine if a link can be demonstrated between ice concentrations and the physical and chemical characteristics of the ambient aerosol. This study combines a 1D kinematic framework with lee wave cloud observations to infer ice nuclei (IN) concentrations that were compared to IN observations from the same flights. About 30 cloud penetrations from six flights were modeled. The temperature range of the observations was −16° to −32°C. Of the three simplified ice nucleation representations tested (deposition, evaporation freezing, and condensation/immersion droplet freezing), condensation/immersion freezing reproduced the lee wave cloud observations best. IN concentrations derived from the modeling ranged from 0.1 to 13 L−1 compared to 0.4 to 6 L−1 from an IN counter. A better correlation was found between temperature and the ratio of IN concentration to the concentration of large aerosol (>500 nm) than between IN concentration and the large aerosol concentration or temperature alone.

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