Ceilometer, sun photometer and ozonometer measurements of the aerosol optical depth,angstrom coefficients, water vapor and total ozone content over Sofia (Bulgaria)

2013 ◽  
Author(s):  
Nikolay Kolev ◽  
Tsvetina Evgenieva ◽  
Nikolay Miloshev ◽  
Plamen Muhtarov ◽  
Doino Petkov ◽  
...  
2011 ◽  
Vol 4 (5) ◽  
pp. 857-863 ◽  
Author(s):  
A. Bayat ◽  
A. Masoumi ◽  
H. R. Khalesifard

Abstract. We are reporting the results of ground-based spectroradiometric measurements on aerosols and water vapor in the atmosphere of Zanjan for the period of October 2006 to September 2008 using a CIMEL CE318-2 sun-photometer. Zanjan is a city in Northwest Iran, located at 36.70° N, 48.51° E, and at an altitude of 1800 m a.m.s.l. (above mean sea level). The spectral aerosol optical depth, Ångström exponent, and columnar water vapor have been calculated using the data recorded by the sun-photometer through the direct measurements on the sun radiance (sun-mode). The average values of aerosol optical depth at 440 nm, columnar water vapor, and the Ångström exponent, α, during the mentioned period are measured as, 0.28 ± 0.14, 0.57 ± 0.37 cm and 0.73 ± 0.30, respectively. The maximum (minimum) value of the aerosol optical depth was recorded in May 2007 (November 2007), and that of columnar water vapor, in July 2007 (January 2008). Using the least-squares method, the Ångström exponent was calculated in the spectral interval 440–870 nm along with α1 and α2, the coefficients of a second order polynomial fit to the plotted logarithm of aerosol optical depth versus the logarithm of wavelength. The coefficient α2 shows that most of the aerosols in the Zanjan area have dimensions larger than 1 micron. The calculated values for α2 − α1 indicate that 80 % of the aerosols are in the coarse-mode (>1 μm) and 20 % of them are in the fine-mode (<1 μm). Comparison of α2 − α1 for the atmosphere over Zanjan with other regions indicates dust particles are the most dominant aerosols in the region.


2010 ◽  
Vol 3 (3) ◽  
pp. 2633-2649 ◽  
Author(s):  
A. Bayat ◽  
A. Masoumi ◽  
H. R. Khalesifard

Abstract. We are reporting the results of ground-based spectroradiometric measurements on aerosols and water vapor in the atmosphere of Zanjan for the period of October 2006 to September 2008 using a Cimel CE318-2 sun-photometer. Zanjan is a city in Northwest Iran, located at 36.70° N, 48.51° E, and at an altitude of 1800 above m.s.l. The spectral aerosol optical depth, Ångström exponent, and columnar water vapor have been calculated using the data recorded by the sunphotometer through direct-beam irradiance measurements of sunlight (sun mode). The average values of aerosol optical depth at 440 nm, columnar water vapor, and the Ångström exponent, α, during the mentioned period are measured as, 0.27±0.16, 0.53±0.37 cm and 0.75±0.46, respectively. The maximum (minimum) value of the aerosol optical depth was recorded in May 2007 (January 2007), and that of columnar water vapor, in July 2007 (January 2008). Using the least-squares method, the Ångström exponent was calculated in the spectral interval 440–870 nm along with the coefficients of a second order polynomial fit (α1 and α2) to the log-log plot of aerosol optical depth versus the wavelength. The coefficient α2 shows that most of the aerosols in the Zanjan area have dimensions larger than 1 μm. The values calculated for α2−α1 indicate that 70% of the aerosols are in the coarse-mode (>1 μm) and 30% of them are in the fine-mode (<1 μm). Comparison of α2−α1 for the atmosphere over Zanjan with other regions indicates dust and anthropogenic aerosols are the most dominant aerosols in the region.


2012 ◽  
Vol 12 (23) ◽  
pp. 11619-11630 ◽  
Author(s):  
V. Estellés ◽  
M. Campanelli ◽  
T. J. Smyth ◽  
M. P. Utrillas ◽  
J. A. Martínez-Lozano

Abstract. The European Skynet Radiometers network (EuroSkyRad or ESR) has been recently established as a research network of European PREDE sun-sky radiometers. Moreover, ESR is federated with SKYNET, an international network of PREDE sun-sky radiometers mostly present in East Asia. In contrast to SKYNET, the European network also integrates users of the CIMEL CE318 sky–sun photometer. Keeping instrumental duality in mind, a set of open source algorithms has been developed consisting of two modules for (1) the retrieval of direct sun products (aerosol optical depth, wavelength exponent and water vapor) from the sun extinction measurements; and (2) the inversion of the sky radiance to derive other aerosol optical properties such as size distribution, single scattering albedo or refractive index. In this study we evaluate the ESR direct sun products in comparison with the AERosol RObotic NETwork (AERONET) products. Specifically, we have applied the ESR algorithm to a CIMEL CE318 and PREDE POM simultaneously for a 4-yr database measured at the Burjassot site (Valencia, Spain), and compared the resultant products with the AERONET direct sun measurements obtained with the same CIMEL CE318 sky–sun photometer. The comparison shows that aerosol optical depth differences are mostly within the nominal uncertainty of 0.003 for a standard calibration instrument, and fall within the nominal AERONET uncertainty of 0.01–0.02 for a field instrument in the spectral range 340 to 1020 nm. In the cases of the Ångström exponent and the columnar water vapor, the differences are lower than 0.02 and 0.15 cm, respectively. Therefore, we present an open source code program that can be used with both CIMEL and PREDE sky radiometers and whose results are equivalent to AERONET and SKYNET retrievals.


2005 ◽  
Vol 11 (5-6) ◽  
pp. 5-11
Author(s):  
A.V. Grytsai ◽  
◽  
O.M. Evtushevsky ◽  
G.P. Milinevsky ◽  
Z.I. Grytsai ◽  
...  

2021 ◽  
Vol 1889 (3) ◽  
pp. 032030
Author(s):  
A N Stepanova ◽  
V A Yakovlev

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