11 research outputs found
Zenith scattered light measurement: Observations of BrO and OClO
No full textStratospheric BrO and OClO observations have been made for the first time over a tropical station, Pune (18° 31′ N, 73° 55′ E) using a Differential Optical Absorption Spectroscopy (DOAS) technique by measuring zenith sky scattered light spectra in the wavelength range of 346–358 nm by ultraviolet (UV)/visible spectrometer. The Differential Optical Density (DOD) fitting technique is applied for the right selection of a suitable spectral region for the analysis to minimize interference and poorly fitting absorption features, and also to minimize the residual of the fit. Observed DODs of O3, NO2, BrO, OClO, O4, Rayleigh and Ring are well fitted with the calculated DODs and the percentage DODs are found to vary up to 0.5%, 0.8%, 0.15%, 0.13%, 1.5%, 1.2% and 1.3% respectively. Chlorine and bromine species play an important role in the ozone depletion, hence O3, NO2, BrO and OClO Slant Column Densities (SCDs) are derived between 76° and 94° Solar Zenith Angles (SZAs). The SCDs of O3 are found to be decreased in the twilight period (i.e. between 90° and 94° SZA) in the presence of sufficient BrO and OClO. Total Column Densities (TCDs) of O3, NO2, BrO and OClO are derived by UV/visible spectrometry, Brewer spectrometry and satellite-based Scanning Imaging Absorption spectrometer for Atmospheric Cartography (SCIAMACHY) for Pune and the higher latitude station Kanpur (26° 28′ N, 80° 24′ E) during the period 1 April–31 June 2008. The day-to-day variations in O3 and NO2 TCDs over Pune are found to be more than over Kanpur. BrO TCDs vary between 1.9 × 1013 and 4 × 1013 molecules cm−2 over Pune, which are derived by UV/visible spectrometry, while they vary for the high-altitude station Kanpur between 0.5 × 1013 and 3.5 × 1013 molecules cm−2 derived by SCIAMACHY. The OClO TCDs are found to have an increasing trend with variations between 2 × 1013 and 4.5 × 1013 molecules cm−2 during the above period
Analysis of sunlight absorption spectra related to atmospheric trace gases in the tropics
No full textZenith sky-scattered light intensity spectra of wavelength ranges of 325–500 nm have been recorded with UV-visible spectrometer over tropical station Pune (18° 31′ N, 73° 55′ E). Zenith scattered light spectra in the spectral range of 346–358 nm are analysed to find out differential optical depth (DOD) for the period 15–18 November 2010. In DOD spectra, depths are noticed at relevant wavelength due to the absorption by atmospheric gases such as NO2 (nitrogen dioxide), O3 (ozone), BrO (bromine monoxide), and OClO (chlorine dioxide). These DOD spectra are analysed by a matrix inversion technique to calculate individual DOD spectrum of the gases. The observed and calculated DODs are found to be in a good agreement. The coefficient of determination (R2) between observed and calculated DODs of NO2, O3, BrO, OClO, O4 (oxygen dimer), and Ring effect are observed to be 0.55, 0.77, 0.73, 0.75, 0.82, and 0.91, respectively. Filling-in of solar Fraunhofer lines in the observed zenith scattered sunlight is known as ‘Ring effect’. The slant column densities of the above gases are found to be increased due to increasing absorption path length with solar zenith angles. The vertical column densities (VCDs) of O3 and NO2 derived using ground-based spectrometer are compared with the Ozone Monitoring Instrument (OMI) on board Aura satellite during the period 1 March–31 December 2010. The day-to-day variations are found to be similar; however, the percentage differences in VCDs of O3 between ground-based spectrometer and satellite-based OMI are observed to be varying from 1% to 15%, while for NO2, they vary from 1% to 10%. Also, the seasonal mean values of VCDs of O3 and NO2 are discussed. The O3 mean values in the rainy season are found to be higher than that of in the summer and winter seasons from both ground- and satellite-based measurement. Whereas, the NO2 mean values in the winter season are found to be higher than that of in the summer and rainy seasons from both the measurement techniques. The VCDs of O3 are observed to be lowest in winter season due to the loss of ozone within NO2 and O3 reaction active during the winter season
Remote sensing ground-based automatic UV/visible spectrometer for the study of atmospheric trace gases
No full textAn advance remote sensing instrument, the ‘ground-based automatic UV / visible spectrometer’, has been developed indigenously at Pune (18° 31′ N, 73° 55′ E) to cover the spectra (462–498 nm) of zenith sky scattered light. A spectrometry technique is used to find out the vertical column density (VCD) of many atmospheric trace gases, such as NO2, O3, H2O and O4. The VCDs of these gases are extracted from observed spectra by comparing the magnitude of the differential optical depth (DOD) of each species in the 462–498 nm spectral range. Slant column densities (SCDs) of each species are found to increase with solar zenith angle (SZA), due to the approaching higher path length of sunlight. The VCDs of O3 and NO2 derived by the UV / visible spectrometer are compared with the ozone monitoring instrument (OMI) Aura satellite and ground-based Brewer spectrometer data. The compared VCD values are found to be close to satellite and ground-based measurement
A Novel Framework To Investigate The Impact Of Social Media Advertising Features On Customer Purchase Intention Using Bwo-Dann
Get PDFSocial Media (SM) has turned out to be a platform for marketing as well as advertising activities. In relation to SM Advertising (SMA), the cultural influence on consumers’ behavior as well as attitude is more vital. Organizations have used up loads of money, time, and also resources on SMA. Nevertheless, it is always a challenge for the organizations to model SM advertisement in a means to effectively attract and also motivate customers into purchasing their brands. This paper proposed a novel framework to scrutinize the SMA features’ impact on Customer Purchase Intention (CPI) by means of the BWO-DANN. Initially, the questionnaires are given to the various customer and their answers are collected. Then, answers will be uploaded and are converted into numerical format into the system. Next, the CSGA-KM is utilizedfor clustering the questionnaires on the base of personal information. Then the BWO-DANN is utilized to train the converted questionnaire set. After that, the system is tested by utilizing KFCV. Finally, through the mean model, CPI is founded out. The extensive experimentation’s outcomes illustrated that the system trounced the other methodologies, and also it is best to examine the CPI
Diurnal asymmetry in slant column density of NO2, O3, H2O and O4 during CAIPEEX–IGOC over Mahabubnagar, a rural site in Southern Peninsular India
No full textIn order to study the column densities of atmospheric trace gases over a rural environment, zenith-sky scattered light observations have been carried out by employing a high-precision, portable UV-V-IR spectrometer (Ocean Optics Model HR2000) at Mahabubnagar (16°42′N, 77°58′E) during the Cloud Aerosol Interaction and Precipitation Enhancement Experiment–Integrated Ground Observational Campaign during October 1, 2011–November 11, 2011. The observed and calculated differential optical density spectra of NO2, O3, H2O and O4 are compared in the spectral range 462–498 nm and found good agreement within a percent deviation up to 1, 1, 0.5 and 0.8 %, respectively. Differential slant column densities (SCDdiff) of NO2, O3, H2O and O4 are retrieved to present the diurnal variation at morning and evening hours between 65° and 95° solar zenith angles (SZAs). The SCDdiff at morning and evening 90° SZA are observed to be 6.4 × 1016 and 9.4 × 1016 mol cm−2 for NO2; 1.03 × 1020 and 1.38 × 1020 mol cm−2 for O3; 1.7 × 1024 and 1.8 × 1024 mol cm−2 for H2O, 1.23 × 1044 and 1.57 × 1044 mol cm−2 for O4, respectively. The diurnal variations of NO2 in twilight period are observed to vary from 36 to 75 %, O3 from 23 to 40 %, H2O from 2 to 20 % and O4 from 23 to 53 % during the study period. The SCDs of NO2, O3 and O4 are observed to be higher in the evening twilight hours compared to the morning twilight hours, which may be due to higher temperature observed at evening as compared to morning between 65° and 95° SZAs
Vertical profile variations of NO2 and O3 using slant column density observations during twilight period
Get PDFAn algorithm developed to derive the vertical profiles of atmospheric species from their slant column density measurements using twilight spectroscopy is discussed. The algorithm has been tested by using the slant column density measurements at polar station, Reykjavik (64°N, 22.6°W) and tropical station, Pune (18.53°N, 73.85°E). The vertical profiles of NO2 and O3 are retrieved by considering slant column densities for ten different solar zenith angles and ten different atmospheric layers of equal thickness. These vertical profiles are used to differentiate the tropospheric and stratospheric contribution of NO2 and O3. The observations of NO2 at polar station and at tropical station showed frequent higher values of tropospheric concentrations due to pollution episodes and are not correlated with stratospheric NO2 and O3. The correlation between total column density variations of NO2 and O3 is not observed; however, the stratospheric variations of NO2 and O3 showed good correlation
Vertical profile variations of NO<sub>2</sub><i> </i>and O<sub>3</sub> using slant column density observations during twilight period
No full text291-301An algorithm developed to derive the
vertical profiles of atmospheric species from their slant column density measurements
using twilight spectroscopy is discussed. The algorithm has been tested by
using the slant column density measurements at polar station, Reykjavik (64°N, 22.6°W)
and tropical station, Pune (l8.53°N, 73.85°E). The vertical profiles of NO2
and O3 are retrieved by considering slant column densities for ten different
solar zenith angles and ten different atmospheric layers of equal thickness. These
vertical profiles are
used to differentiate the tropospheric and
stratospheric contribution of NO2 and O3 . The
observations of NO2 at polar station
and at tropical station showed frequent higher values of tropospheric concentrations
due to pollution episodes and are not correlated with stratospheric NO2
and O3. The correlation between total column density variations of NO2
and O3 is not observed; however, the stratospheric variations of NO2
and O3 showed good correlation
Study of diurnal and seasonal variation of atmospheric NO2, O3, H2O and O4 at Pune, India
Get PDFStudy of diurnal and seasonal variation of atmospheric trace gases is essential to understand our atmosphere. For this, daily zenith-sky scattered light observations have been made by UV-visible spectrometer during the period 2000-2003. Slant column densities (SCD) from morning (solar zenith angle SZA = 90º) to evening (SZA = 90º) were retrieved to see the diurnal variation of NO2, O3, H2O and O4. For the study of seasonal behavior of NO2 and O3, vertical column densities (VCD) were retrieved during the above period. For the whole period, NO2 and O3 VCD are found in a positive correlation of r = 0.72 for the morning data and r = 0.79 for the evening data. Satellites borne observations are compared with the spectroscopic observations, which are found in good correlation. It is seen that highest NO2 and O3 VCD are found in summer months (May and June) and lowest in winter months (December and January). Evening NO2 VCD are found higher compared to morning. There is found an interesting seasonal change that at Pune (18º32´ N, 73º51´ E), the evening-to-morning (PM/AM) ratios of NO2 as well as temperature maximum/minimum ratios are higher in winter months and lower in summer months during the above period. In winter months NO2 PM/AM ratio goes up to 3.8 and in summer months lowest ratio is 1.25. During the day, N2O5 can be photolyzed to regenerate NO2, which reflects in the evening hours. In the winter, nights are longest; therefore, during night NO2 to N2O5 conversion is more, hence in the morning NO2 value will be less that leads to high PM/AM ratio. O3 PM/AM ratio is slightly higher in winter months compared to summer months.EL ESTUDIO DE LA VARIACIÓN DIURNA Y ESTACIONAL DE LOS GASES TRAZA ATMOSFÉRICOS ES ESENCIAL PARA ENTENDER NUESTRA ATMÓSFERA. PARA ESTO, EN EL PERÍODO 2000-2003 SE REALIZARON OBSERVACIONES DIARIAS DE LUZ ZENITAL DISPERSAUTILIZANDO UN ESPECTRÓMETRO UV-VISIBLE. PARA OBSERVAR LAS VARIACIONES DIURNAS DE NO2, O3, H2O Y O4, SE OBTUVIERON LAS DENSIDADES DE COLUMNA INCLINADA (SCD) DESDE LAS MAÑANAS (ÁNGULO ZENITAL SOLAR (SZA) = 90°) HASTA LAS TARDES (SZA = 90°). PARA EL ESTUDIO DE LAS VARIACIONES ESTACIONALES DE NO2 Y O3, SE OBTUVIERON LAS DENSIDADES DE COLUMNA VERTICAL (VCD) DURANTE EL PERÍODO MENCIONADO. PARA LOS DATOS DE VCD DE NO2 Y O3, SE ENCONTRÓ UNA CORRELACIÓN POSITIVA DE R = 0.72 PARA LAS MAÑANAS Y DE R = 0.79 PARA LAS TARDES. SE COMPARARON LAS OBSERVACIONES DE SATÉLITE CON LAS ESPECTROSCÓPICAS Y SE OBSERVÓ UNA BUENA CORRELACIÓN. LOS VALORES MÁS ALTOS DE VCD PARA NO2 Y O3 APARECEN EN LOS MESES DE VERANO (MAYO Y JUNIO) Y LOS MÁS BAJOS EN LOS MESES DE INVIERNO (DICIEMBRE Y ENERO). LAS VCD VESPERTINAS DEL NO2 SON MÁS ALTAS QUE LAS MATUTINAS. PARA LA CIUDAD DE PUNA (18°32"" N, 73°51"" E) SE ENCONTRÓ UN CAMBIO ESTACIONAL INTERESANTE: LAS TASAS VESPERTINA/MATUTINA (PM/AM) DE NO2 Y DE LAS TEMPERATURAS MÁXIMAS/MÍNIMAS SON MAYORES EN LOS MESES DE INVIERNO QUE EN LOS DE VERANO PARA TODO EL PERÍODO DE ESTUDIO. EN LOS MESES DE INVIERNO LA TASA PM/AM DEL NO2 LLEGA HASTA 3.8 Y LA MENOR PARA LOS MESES DE VERANO ES DE 1.25. DURANTE EL DÍA, EL N2O5 PUEDE FOTOLIZARSE PARA REGENERAR NO2, LO QUE SE REFLEJA EN LAS TARDES. EN EL INVIERNO LAS NOCHES SON MÁS LARGAS, POR LO QUE DURANTE ELLAS LA CONVERSIÓN DE NO2 EN N2O5 ES MAYOR Y LOS VALORES DE NO2 SON MENORES EN LAS MAÑANAS, LO QUE PRODUCE UNA TASA PM/AM ELEVADA. LA TASA PM/AM DEL O3 ES LIGERAMENTE MÁS ELEVADA EN LOS MESES DE INVIERNO QUE EN LOS DE VERANO
Influence of tropospheric clouds on ground-based measurements of stratospheric trace gases at Tropical station, Pune
No full textThe effects of tropospheric clouds on the measurements of the stratospheric trace species like NO2, O3, H2O and O4 using differential optical absorption spectroscopy have been discussed. For the present study, the spectroscopic observations were carried out in the spectral region 462–498 nm at Pune (18°32′N, 73°51′E) on cloudy days from 4 May to 29 November 2000. Differential slant column density (SCDdiff) of NO2, O3, H2O and differential optical depth of O4 are derived to make the comparison between clear and cloudy sky conditions. Also, daily vertical column densities (VCDs) of O3 and NO2 are computed. Additional optical path lengths (enhanced/reduced path lengths in cloudy sky condition compared to clear sky condition) are derived at 90° solar zenith angle (SZA) for cloudy days using O3 densities. The enhancements/reductions in the path lengths inside the clouds affect the ground-based measurements of the stratospheric gases. The study reveals that the enhancement in the densities of above gases are found inside the optically thick clouds like Cb, Ac whereas reductions in the densities are noticed in optically thin clouds like Ci, As in comparison with clear sky case. Langley plots of SCDdiff of O3 also support the above facts. Enhancement in optical path length during Indian southwest summer monsoon season (June–September 2000) and pre monsoon (May 2000) appears to be due to multiple reflections between layered clouds. Whereas, enhancement in optical path lengths during post-monsoon (October–November 2000) season appears to be linked with photon diffusion, multiple Mie-scattering and multiple reflections due to isolated patches of optically thick clouds. The reductions in optical path lengths due to optically thin clouds are noticed during all the above seasons. Prominent day-to-day variability in the VCDs of NO2 and O3 is observe
Variations of O<sub>3</sub>, NO<sub>2 </sub>and O<sub>4</sub> densities in association with NAO indices during winter/spring of 1993/94 and 1994/95 at sub-Arctic station
No full text104-114<span style="font-size:12.0pt;line-height:
115%;font-family:" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";="" mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">A study
of the atmospheric trace constituents like O3, NO2 and O4
has been made in the visible spectral region 550-595 nm. The data for the above
study have been obtained from the daily observations of the light intensity taken
at twilight hours in the early morning and evening by using an automatic spectrometer
at the sub-Arctic station Reykjavik (64°N, 22.6°W) for the months December-April
(winter/spring) of 1993/94 and 1994/95. The Differential Optical Absorption Spectroscopy
(DOAS) technique has been used to obtain slant column density (SCD) of O3,
NO2 and O4 from the above light intensity. Further, vertical
column densities (VCDs) of O3 and NO2 have also been calculated
at solar zenith angle (SZA) 90° by dividing above SCD with a proper value
of air mass factor. The results of the above analyses have shown that there exists
a predominant daily variation in the VCDs of O3 and VCDs of O2
at both morning and evening twilight hours. There exists one oscillation within
the daily variations of O3 and NO2; this oscillation is confined
to the same period of 3-10 days (visual appearance). These periodic oscillations
are found to have coincided with the oscillation of the stratospheric warm and cold
episodes during the above period of observations. It is interesting to note that
the evening twilight hour magnitudes of O3 and NO2 are slightly
higher than those of the morning twilight hour magnitudes, but they are in phase
with each other. The variations of the VCD O3 and VCD NO2
have been correlated with the North Atlantic oscillation (NAO) index. The correlation
coefficients are +0.2 1 and +0.25 between VCD O3 and NAO index in 1993/94
and 1994/95, respectively. But VCDs of NO2 seldom show any relationship
with NAO index. Also, the daily variations in SCDs of O4 are studied
in connect ion with the different types of clouds prevailing at the Arctic station
during winter/spring of 1993/94 and 1994/95. There exists strong variability of
<span style="font-size:12.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:hiddenhorzocr;mso-ansi-language:="" en-in;mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">O4 with variations of the type of clouds.</span
