Atmospheric aerosol particles were collected at Camag¨uey (21.42° N, 77.85°W, 122 m asl), Cuba, during 2010 and 2012-2014, for investigating the absorption of light by particles, particulate matter (PM) concentration, and elemental composition. Samples were collected with a low volume particulate Dekati PM10 impactor twice a week with a collection time of 24 hours. The sample flow rate was 15 l/min. Gravimetric analysis of the particulate matter fractions PM1 (PM< 1 μm) was carried out for 104 samples. An Integrating Sphere Spectral System (IS3) was developed for measuring the spectral absorption coefficient from the UV to the visible wavelengths with a spectral resolution of 10 nm. The system uses a filter-based method. The light absorption is determined by measuring and comparing the intensity of light transmitted by filters with and without particles deposited. The IS3 is fully described in this work. It consists of a 6-inch integrating sphere with a spectral reflectance of 98 % that covers the wavelength range from 250 to 2500 nm. The light source includes a 150W xenon lamp included in an ORIEL APEX illuminator equipped with a transmission filter, and an automated scanning monochromator. The signal is detected by a compact size Si detector (200-1100 nm) connected to a light meter. With this approach continuous spectra of the absorption coefficients in the 320-800 nm spectral range can be obtained with variable spectral resolution. Spectral absorption coefficients measured by the IS3 are presented and analyzed for the campaign period.
Nikolay Kolev, Tsvetina Evgenieva, Sandra Blindheim, Barbara Lahnor, Sandra Mogo, Alberto Berjon, Edith Rodriguez, Kerstin Stebel, Victoria Cachorro, Michael Gausa, Ivan Kolev
Aerosol structure measurements in the troposphere were carried out at the Arctic Lidar Observatory for Middle
Atmosphere Research (ALOMAR), Norway, during summer 2007. ALOMAR troposheric lidar and Cimel CE-318 sun
photometer were used to implement the aerosol measurements. Three wavelengths of the sounding laser radiation were
used during the experiment λ1=1064nm, λ2=532nm and λ3=355nm which brings additional information about
atmospheric aerosol optical and microphysical characteristics in the whole troposphere. The experimental data could be
arranged in two groups: days when Ci-clouds were observed (in June) and days when the meteorological situation is
characterized with clear sunny weather (in the beginning of July). In days with presence of Ci-clouds two layers are
observed in the planetary boundary layer-the first one with maximum height from 1500m to 2000m; the second one
with maximum height from 2000m to 3000m. In clear sunny days few layers are observed with minimum height from
1500m to 2300m and maximum height around H=6000m. The height of the layers remains constant or decrease with
time. The lidar data are juxtaposed with the data obtained by the sun photometer.
In present work the wave aberration is determined for the general case of the concave diffraction grating monochromator using of the direction cosines of the diffracted ray. These direction cosines are found from the ray tracing through the monochromator. The ray tracing includes the holographic grating recording system and the optical system of the monochromator as well. The results of the optimization of the wave aberration and of the light path function are compared for the example of diffraction monochromator.
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