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Lidar Measurements of Aerosols in the Tropical Atmosphere

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Advances in Atmospheric sciences 1993年第3期10卷 365-378页

作者： p.c.s.devara p.Ernest Raj Indian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 India

Measurements of atmospheric aerosols and trace gases using the laser radar (lidar) techniques, have been in progress since 1985 at the Indian Institute of Tropical Meteorology, pune (18°32'N, 73°51'E, 559 m AMsL), India. These observations carried out during nighttime in the lower atmosphere (up to 5.5 km AGL), employing an Argon ion / Helium-Neon lidar provided information on the nature, size, concentration and other characteristics of the constituents present in the tropical atmosphere. The time-height variations in aerosol concentration and associated layer structure exhibit marked differences between the post-sunset and pre-sunrise periods besides their seasonal variation with maximum concentration during pre-monsoon / winter and minimum concentration during monsoon months. These observations also revealed the influence of the terrain of the experimental site and some selected meteorological parameters on the aerosol vertical distributions. The special observations of aerosol vertical profiles obtained in the nighttime atmospheric boundary layer during October 1986 through september 1989 showed that the most probable occurrence of mixing depth lies between 450 and 550 m, and the multiple stably stratified aerosol layers present above the mixing depth with maximum frequency of occurrence at around 750 m. This information on nighttime mixing depth / stable layer derived from lidar aerosol observations showed good agreement with the height of the ground-based shear layer / elevated layer observed by the simultaneously operated sodar at the lidar site.

关键词： Laser radar Atmospheric aerosols Aerosol layer Nocturnal boundary layer Tropics

Atmospheric NO_2 concentration Measurements Using Differential Absorption Lidar Technique

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Advances in Atmospheric sciences 1992年第1期9卷 73-82页

作者： p.c.s.devara p.Ernest Raj Indian Institute of Tropical Meteorology Pune-411008 IndiaIndian Institute of Tropical Meteorology Pune-411008 India

Using the Differential Absorption Lidar (DIAL) technique, two types of approaches, namely, reflection from retroreflector / topographic target and backscatter from atmosphere, are available for studying remotely the atmospheric NO, concentration. The Argon ion lidar system at the Indian Institute of Tropical Meteorology (IITM), pune, India has been used for the measurements by following both the path-averaged and range-resolved approaches. For the former, a topographic target (hill) is used for determining path-averaged surface concentration. In the latter, spectral properties of atmospheric attenuation is used for making range-resolved measurements in the surface layer. The results of the observations collected by following both approaches are presented. The average surface NO2 concentration was found to vary between 0.01 and 0.105 ppm and the range-resolved measurements exhibited higher values suggesting treatment of the lidar data for scattering and extinction effects due to atmospheric aerosols and air molecules, and atmospheric turbulence. certain modifications that are suggested to the experimental set-up, data acquisition and analysis to improve the measurements are briefly described.

关键词： Atmospheric NO2 concentration Measurements Using Differential Absorption Lidar Technique NO

some Aspects of the Diurnal and semidiurnal Tidal Wind Field in Meteor Zone

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Advances in Atmospheric sciences 1989年第3期6卷 357-364页

作者： p.c.s.devara G.chandrasekhar M.I.Ahmed Indian Institute of Tropical Meteorology Pune 411005IndiaDepartment of PhysicsAndhra UniversityWaltair 530003.IndiaDepartment of PhysicsAndhra UniversityWaltair 530003.India

The diurnal and semidiurnal tidal wind field variations in the altitudes between 80 and 100 km of the earth's atmosphere over a mid-latitude station are studied by means of the phases of the zonal and meridional wind measurements made at Atlanta (34 ° N, 84 ° W). The rotation of diurnal tidal wind vector is seen to be clockwise at lower heights (80-86 km), swinging between clockwise and anti-clockwise at intermediate heights (88-96 km) and anti-clockwise at higher heights (96-100 km). The senses of rotation of diurnal and semidiurnal tidal wind vectors are compared between the stations located in the same and opposite hemispheres. The results are consistent with the tidal theory in the case of Atlanta and Adelaide (35°s, 139 ° E) whereas in the case of other stations considered in the present study, they showed marked variations.

关键词： ph some Aspects of the Diurnal and semidiurnal Tidal Wind Field in Meteor Zone Wind

sEAsONAL VARIATION OF LIDAR-DERIVED AEROsOL cONTENT IN THE LOWER LAYERs OF THE ATMOspHERE

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Acta meteorologica sinica 1990年第1期4卷 113-119页

作者： p.Ernest Raj p.c.s.devara Indian Institute of Tropical Meteorology,pune-411 005,India

Results of the study of seasonal variation of total column content of aerosols in the 50—1100 m height region are presented,The columnar content of aerosols is computed by integrating the height profiles of nighttime aerosol number density estimated from the Argon ion lidar observations collected at the ⅡTM, pune for the one year period from October 1986 to september *** results of the study indicated that the aerosol content was higher during winter than during monsoon months by over 78% with an annual mean columnar aerosol content of 1.66×10~8 cm^(-2).The observed seasonal variaticn of aerosol content was found to be associated with that of surface wind,temperature,relative humidity(R.H.)and rainfall data recorded for the above one year period at the station.

关键词： sEAsONAL VARIATION OF LIDAR-DERIVED AEROsOL cONTENT IN THE LOWER LAYERs OF THE ATMOspHERE

seasonal　Variations　in　the　Vertical　structure　of　Water　Vapor　Optical　Depth　in　the　Lower　Troposphere　over　a　Tropical　station

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Advances in Atmospheric sciences 1997年第1期14卷 104-111页

作者： p. Ernest Raj and p.c.s. devara Indian Institute of Tropical Meteorology, pune-411008, India Indian Institute of Tropical Meteorology Pune India

spatio-temporal variations of water vapor optical depth in the lower troposphere (450-3850 m) over pune (18°32′N, 73°51′E, 559 m Above Mean sea Level), India have been studied over a period of five years. The mean vertical structure showed that the moisture content is greatest at the lowest level and decreases with increasing altitude, except in the south-west monsoon season (June to september) where an increase upto 950 m has been found. Optical depths are maximum in the monsoon season. The increase from pre-monsoon (March-May) to monsoon season in moisture content on an average is by about 58% in the above altitude range. The temporal variations in surface Relative Humidity and optical depth at 450 m show positive correlation. The amplitude of seasonal oscillation is the largest at 1465 m altitude. The time-height cross-sections of water vapor optical depths in the lower troposphere showed a contrast between years of good and bad monsoon.

关键词： Optical depth precipitable water

Aircraft Observations of Electrical conductivity in Warm clouds

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Advances in Atmospheric sciences 1993年第1期10卷 95-102页

作者： p.Ernest Raj p. c. s. devara A. M. selvam A. s. R. Murty Indian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 India

Aircraft observations of electrical conductivity and cloud microphsical, dynamical and other electrical parameters were made in warm stratocumulus and cumulus clouds forming during the summer monsoon seasons (June-september) of 1983 and 1985 in the Deccan plateau region, India. A Gerdien type cylindrical condenser was used for the measurement of electrical conductivity. The variations in the electrical conductivity are observed to be closely associated with the updrafts and downdrafts in the cloud, liquid water content, cloud droplet charge and corona discharge current. The value of electrical conductivity in warm clouds is found to be in the order of 10-12 ohm-1 m-1 which is two orders higher than that observed in clear-air at cloud-base levels in some regions by other *** static electricity concepts predict reduced conductivity values inside clouds. cloud electrical conductivity measurements, particularly in warm clouds are few and the results are contradictory. The recently identified mechanism of vertical mixing in clouds lends support to convective charge separation mechanism with inherent larger than clear-air values for cloud electrical conductivity and therefore consistent with the measurements reported herein.

关键词： Aircraft Observations of Electrical conductivity in Warm clouds

serological surveillance for sARs-coV-2 antibodies among students,faculty and staff within a large university system during the pandemic

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World Journal of Virology 2025年第1期14卷 99-107页

作者： Marcos G pinheiro Gabriela G O Alves Maria Eduarda R conde sofia L costa Regina c s sant’Anna Isa M F Antunes Mônica c carneiro Fabio s Ronzei Julia c scaffo Felipe R pinheiro Lialyz s Andre Helvecio c povoa Valéria T Baltar Fabíola Giordani Eduarda s Hemerly Gisele c Alexandre Karla c de paula Márcio Watanabe Antonio claudio L da Nóbrega Jackeline christiane p Lobato Fabio Aguiar-Alves Laboratory of Molecular Epidemiology and Biotechnology Rodolpho Albino University LaboratoryFluminense Federal UniversityNiterói 24241000Rio de JaneiroBrazil Estácio de sáUniversity Nova Friburgo 28611135Rio de JaneiroBrazil pathology program Medicine schoolFluminense Federal UniversityNiterói 24070090Rio de JaneiroBrazil Department of pharmaceutical sciences Lloyd L.Gregory School of PharmacyPalm Beach Atlantic UniversityWest Palm BeachFL 33401United States Health Institute of Nova Friburgo Fluminense Federal UniversityNova Friburgo 28613001Rio de JaneiroBrazil Department of Epidemiology and Biostatistics Institute of Collective Health(ISC)Fluminense Federal UniversityNiterói 24033900Rio de JaneiroBrazil Institute of physical Education Fluminense Federal UniversityNiterói 24020005Rio de JaneiroBrazil Department of statistics Fluminense Federal UniversityNiterói 24210200Rio de JaneiroBrazil Department of physiology and pharmacology Fluminense Federal UniversityNiterói 24210130Rio de JaneiroBrazil

BAcKGROUND At the end of December 2019,the world faced severe acute respiratory syndrome-coronavirus 2(sARs-coV-2),which led to the outbreak of coronavirus disease 2019(cOVID-19),associated with respiratory *** virus has shown significant challenges,especially for senior citizens,patients with other underlying illnesses,or those with a sedentary *** tests conducted early on have helped identify how the virus is transmitted and how to curb its *** study hypothesis was that the rapid serological test for sARs-coV-2 antibodies could indicate the immunoreactive profile during the cOVID-19 pandemic in a university *** To conduct active surveillance for serological expression of anti-sARs-coV-2 antibodies in individuals within a university setting during the cOVID-19 *** This sectional study by convenience sampling was conducted in a large university in Niteroi-RJ,Brazil,from March 2021 to July *** study population consisted of students,faculty,and administrative staff employed by the university.A total of 3433 faculty members,60703 students,and 3812 administrative staff were invited to *** were gathered through rapid serological tests to detect immunoglobulin(Ig)M and IgG against ***χ²or Fisher's exact test was used to conduct statistical analysis.A 0.20 significance level was adopted for variable selection in a multiple logistic regression model to evaluate *** A total of 1648 individuals were enrolled in the *** proportion of cOVID-19 positivity was 164/1648(9.8%).The adjusted logistic model indicate a positive association between the expression of IgM or IgG and age[odds ratio(OR)=1.16,95%cI:1.02-1.31](ps who had been in contact with a cOVID-19-positive case(OR=3.49,95%cI:2.34-5.37)(pse who had received the cOVID-19 vaccine(OR=2.33,95%cI:1.61-3.35)(psocial isolation(OR=0.59,95%cI:0.41-0.84)(psho

关键词： serological surveillance sARs-coV-2 antibodies cOVID-19 serological rapid test Risk factors for cOVID-19

cloud condensation Nuclei over the Bay of Bengal during the Indian summer Monsoon

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Advances in Atmospheric sciences 2018年第2期35卷 218-223页

作者： D. M. cHATE R. T. WAGHMARE c. K. JENA V. GOpALAKRIsHNAN p. MURUGAVEL sachin D. GHUDE Rachana KULKARNI p. c. s. devara Indian Institute of Tropical Meteorology Pune 411008 India Marine Earth and Atmospheric Science North Carolina State University Raleigh NC 27695 USA Amity centre for Ocean-Atmospheric science and Technology (AcOAsT) & Amity centre for Environmental science and HeaLsTh (AcEsH) Amity University Haryana Gurgaon-Manesar 122 413 India

The first measurements of cloud condensation nuclei （ccN） at five supersaturations were carried out onboard the research vessel ＂sagar Kanya＂（cruise sK-296） from the south to the head-bay of the Bay of Bengal as part of the continental Tropical convergence Zone （cTcZ） project during the Indian summer monsoon of 2012. In this paper, we assess the diurnal variation in ccN distributions at supersaturations from 0.2% to 1% （in steps of 0.2%） and the power-law fit at supersaturation of 1%. The diurnal pattern shows peaks in ccN concentration （NccN） at supersaturations from 0.2% to 1% between 0600 and 0700 LsT （local standard time, UTc＋0530）, with relatively low concentrations between 1200 and 1400 LsT, followed by a peak at around 1800 LsT. The power-law fit for the ccN distribution at different supersaturation levels relates the empirical exponent （k） of supersaturation （%） and the Nccy at a supersaturation of 1%. The Nccy at a supersaturation of 0.4% is observed to vary from 702 cm-3 to 1289 cm-3, with a mean of 961 ＋ 161 cm-3 （95% confidence interval）, representing the ccN activity of marine air masses. Whereas, the mean Nccy of 1628 ＋ 193 cm-3 at a supersaturation of 1% is higher than anticipated for the marine background. When the number of ccN spectra is 1293, the value of k is 0.57 ± 0.03 （99% confidence interval） and its probability distribution shows cumulative counts significant at k ≈ 0.55 ± 0.25. The results are found to be better at representing the features of the marine environment （103 cm-3 and k ≈ 0.5） and useful for validating ccN closure studies for Indian sea regions.

关键词： cTcZ Bay of Bengal monsoon, ccN supersaturation power-law relationship

Energy and exergy analysis of syngas production from different biomasses through air-steam gasification

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Frontiers in Energy 2020年第3期14卷 607-619页

作者： s.Rupesh c.Muraleedharan p.Arun Department of Mechanical Engineering National Institute of Technology CalicutCalicut 673601India

Gasification is a thermo-chemical reaction which converts biomass into fuel gases in a *** efficiency of conversion depends on the effective working of the *** first step in the conversion process is the selection of a suitable feedstock capable of generating more gaseous *** paper analyses the performance of different biomasses during gasification through energy and exergy analysis.A quasi-equilibrium model is developed to simulate and compare the feasibility of different biomass materials as gasifier ***-metric studies are conducted to analyze the effect of temperature,steam to biomass ratio and equivalence ratio on energy and exergy *** the biomasses considered,sawdust has the highest energy and exergy efficiencies and lowest *** a gasification temperature of 1000 K,the steam to biomass ratio of unity and the equivalence ratio of 0.25,the energy efficiency,exergy efficiency and irreversibility of sawdust are 35.62%,36.98%and 10.62 MJ/kg,*** is also inferred that the biomass with lower ash content and higher carbon content contributes to maximum energy and exergy efficiencies.

关键词： gasification modeling energy exergy syngas