Yu. S. Balin

Investigations of the vertical distribution of troposphere aerosol layers based on the data of multifrequency Raman lidar sensing: Part 1. Methods of optical parameter retrieval

A technique intended for interpreting the data of multifrequency Raman lidar sensing is developed. An algorithm for separating aerosol layers with different scattering properties and the subsequent estimation of the average value of the lidar ratio and Angström parameter within the individual layers is proposed. The algorithm allows the error of retrieving the backscattering coefficient from daytime observations to be at least halved. To interpret the data of nighttime observations, a well-posed algorithm of numerical differentiation intended for determining the extinction coefficient based on the transformation of the range of allowable values which requires a solution of nonlinear equations is developed. An iterative procedure yielding an improved spatial resolution as compared with the conventional methods is envisaged for linearization. The methods can be successfully used for processing routine lidar measurements under conditions of a priori uncertainty.

Results of joint observations of aerosol perturbations of the stratosphere at the CIS-LiNet network in 2008

The results of lidar observations of stratospheric aerosol perturbations for the period of July–November 2008 at three lidar stations of the CIS-LiNet network in Tomsk, Minsk, and Vladivostok are presented along with the results obtained in the Gobi Desert during a research expedition. The behavior of stratospheric profiles of the scattering ratio R(H) (ratio of the total aerosol and molecular backscattering coefficient to the molecular backscattering coefficient) is analyzed at different wavelengths characterizing the aerosol stratification in the stratosphere. The transport of air masses in the stratosphere is studied by the method of direct and backward trajectories using the NOAA HYSPLIT model. It is shown that stratospheric aerosol perturbations are connected with explosive eruptions of volcanoes of the Aleutian islands Okmok (53.4° N, 168.1° W; July 12, 2008) and Kasatochi (52.2° N, 175.5° W; August 6–8, 2008).

Investigation of the vertical distribution of tropospheric aerosol layers from multifrequency laser sensing data. Part 2: The vertical distribution of optical aerosol characteristics in the visible region

Regular lidar measurements of the vertical aerosol distribution were conducted in Tomsk (56° N, 85° E) from March 2006 to October 2007 as part of the CISLINET (CIS Lidar Network) project. The statistical analysis of the profiles of the aerosol backscattering coefficients βa (532 nm), extinction coefficients σa (532 nm), and lidar ratio Sa (532 nm) from the data of nocturnal measurements by Raman lidar (532 and 607 nm) in the altitude range from 0.45 to 7 km is presented. According to these measurements, the mean height of the top boundary of the boundary layer (BL) is 1.22 km for the cold period of observations (from October to March) and 2.3 km for the warm period (from April to September). The mean value of σa (532 nm) for the cold period of observations in the BL is 0.025 km−1, which is more than two times lower than the mean value of 0.061 km−1 for the warm observation period. The mean value of Sa (532 nm) in the BL is independent of the observation season and is equal to 52 sr. Above the BL, in the free troposphere (FT), the coefficients βa (532 nm) and βa (532 nm) are proportional to the molecular scattering coefficient. The mean value of σa (532 nm) is 0.0083 km−1 for the cold period and 0.011 km−1 for the warm period. The lidar ratio in the FT is 43.5 sr in the cold period. This value is nearly 10 sr lower than the mean lidar ratio for the warm period (52.8 sr).

Investigation of the ground layer of the atmosphere and clouds using laser location

Apparatus for measuring certain parameters of the atmosphere and clouds by laser location is described. The results of measurements of the radiation attenuation factor in the ground layer of the atmosphere, in clouds, and in fog are presented.

Structure of aerosol fields of the atmospheric boundary layer according to aerosol and Doppler lidar data during passage of atmospheric fronts

The paper presents the results of complex observations of the atmospheric boundary layer dynamics performed at the Fonovaya Observatory of the Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, in September 2013, with the use of remote sensing facilities, i.e., aerosol and Doppler lidars. The structure of aerosol and wind fields in the period of occurrence of internal buoyancy waves and low-level jet streams in the boundary layer is considered.

Investigation of the Vertical Distribution of Tropospheric Aerosol Layers Using the Data of Multiwavelength Lidar Sensing. Part 3. Spectral Peculiarities of the Vertical Distribution of the Aerosol Optical Characteristics

The spectral peculiarities of the distributions of the backscattering βa(λi, z) and extinction σa(λi, z) coefficients, as well as lidar ratio Sa(λi, z) estimated from the data of multi-wavelength sensing in Tomsk (56° N, 85° E) in the height range from 0.5 to 7.5 km are presented here. Based on observations since April till October 2007 it is shown that in the boundary layer (except of the internal mixing layer) ηβ(532/1064) > ηβ(355/532), and, simultaneously, ησ(532/1064) > ησ(355/532), where ηi are the values of the Ågström parameter for the respective coefficients. Such a distribution of the Ågström parameters is caused by prevalence of small particles with mean geometric radius Rf < 0.15 μm in the volume distribution. On the contrary, in the free troposphere ηβ(532/1064) < ηβ(355/532) and ησ(532/1064) < ησ(355/532). Hence, Rf > 0.15 μm, and the contribution of large particles is governing. In the boundary layer, the lidar ratio decreases with increasing wavelength; the average values are 59.7 (15) sr at 355 nm, 51.1 (8.3) sr at 532 nm, and 47.3 (13.5) sr at 1064 nm. In the free troposphere, the wavelength behavior of the lidar ratio can be different; the average values are 50.4 (8.5) sr at 355 nm, 49.5 (5.7) sr at 532 nm, and 55.3 (10) sr at 1064 nm. The aerosol contribution of the free troposphere to the total aerosol optical depth grows with decreasing boundary layer height; on average, it is 22 (17)% at 355 nm, 27 (19)% at 532 nm, and 34 (22)% at 1064 nm.

Lidar and in situ measurements of the optical parameters of water surface layers in Lake Baikal

The spatial distribution of the extinction coefficient of the upper water layer of Lake Baikal was studied with lidar, installed onboard the R/V G. Yu. Vereshchagin. The vertical profiles of the optical parameters, namely, the backscattering and extinction coefficients, were measured at hydrologic stations. Lidar and in situ measurements are compared, and the reasons why subsurface layers of elevated turbidity are difficult to detect with elastic lidars are discussed.

Complex experiment on the study of microphysical, chemical, and optical properties of aerosol particles and estimation of atmospheric aerosol contribution in the Earth radiation budget

The main aim of the work was complex experimental measurements of microphysical, chemical, and optical parameters of aerosol particles in the surface air layer and free atmosphere. From the measurement data, the entire set of aerosol optical parameters was retrieved, required for radiation calculations. Three measurement runs were carried out in 2013 within the experiment: in spring, when the aerosol generation maximum is observed, in summer (July), when the altitude of the atmospheric boundary layer is the highest, and in the late summer – early autumn, when the second nucleation period is recorded. The following instruments were used in the experiment: diffusion aerosol spectrometers (DAS), GRIMM photoelectric counters, angle-scattering nephelometers, aethalometer, SP-9/6 sun photometer, СЕ 318 Sun-Sky radiometer (AERONET), MS-53 pyrheliometer, MS-802 pyranometer, ASP aureole photometer, SSP scanning photometer, TU-134 Optik flying laboratory, Siberian lidar station, stationary multiwave lidar complex LOZA-M, spectrophotometric complex for measuring total ozone and NO2, multivariable instrument for measuring atmospheric parameters, METEO-2 USM, 2.4 AEHP-2.4m station for satellite data receive. Results of numerical calculations of solar down-fluxes on the Earth’s surface were compared with the values measured in clear air in the summer periods in 2010—2012 in a background region of Siberian boreal zone. It was shown that the relative differences between model and experimental values of direct and total radiation do not exceed 1% and 3%, respectively, with accounting for instrumental errors and measurement error of atmospheric parameters. Thus, independent data on optical, meteorological, and microphysical atmospheric parameters allow mutual intercalibration and supplement and, hence, provide for qualitatively new data, which can explain physical nature of processes that form the vertical structure of the aerosol filed.

COMPARISON OF THE WATER VAPOR AND AEROSOL PROFILES

Analysis of the contents of water vapor and aerosol in the atmosphere measured by means of different instruments was performed based on the results of the comprehensive aerosol experiment carried out at the Institute of Atmospheric optics in May 2012. The data obtained using remote (lidar) and contact (balloon) methods were used. They are capable of obtaining the vertical profiles of the measured parameters with high spatial resolution. Lidar measurements of the water vapor content in the boundary layer of the atmosphere by Raman method have shown very good agreement with the data of measurements by balloon. Simultaneous lidar measurements of backscattering and mixing ratio of water vapor in the atmosphere give significant positive correlation of the contents of water vapor and aerosol in the layers.

Specific Features of the Aerosol Fields Vertical Structure Formation as Observed over the City of Tomsk in Summer 1995

In this paper we discuss some peculiarities in the vertical structure of aerosol fields based on analysis of the vertical profiles of the aerosol scattering coefficient and altitude behavior of the autocorrelation matrices. The differences in the diurnal behaviors of scattering coefficients and the degree of their interlevel correlation are explained by the synoptic situation and the air mass type observed during the studies.