Ioganes E. Penner

Observations of specular reflective particles and layers in crystal clouds

In the present article, results of observations of high crystal clouds with high spatial and temporal resolution using the ground-based polarization LOSA-S lidar are described. Cases of occurrence of specularly reflective layers formed by particles oriented predominantly in the horizontal plane are demonstrated. Results of measuring echo-signal depolarization are compared for linear and circular polarization states of the initial laser beam.

Optik-É AN-30 Aircraft Laboratory for Studies of the Atmospheric Composition

AbstractThe scientific instrumental complex of the Optik-E AN-30 aircraft laboratory developed at the Institute of Atmospheric Optics of the Siberian Branch of the Russian Academy of Sciences is described in detail. Specifications of the main units of the instrumental complex are presented. Special attention is given to the metrological support of measurements of the atmospheric parameters. Experimental capabilities of the aircraft laboratory are illustrated by the results obtained in recent flights over various regions of the Russian Federation.

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).

Expanding the dynamic range of a lidar receiver by the method of dynode-signal collection

A method of lidar data collection by simultaneous registration of signals from the anode and several dynodes of the photomultiplier is suggested. The dynamic range of the receiver has been extended as many as 5 orders of magnitude in the case of cloud sensing. The stable operation under strong background illumination is possible without losses in fine signal structure.

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.

Development of photodetectors for recording lidar signals in the photon counting and analog modes

A number of unified photodetector modules providing for recording lidar signals in the wavelength range from 0.26 to 1.6 μm in the modes of analog signals and photon counting are developed on the basis of photomultiplier tubes and avalanche photodiodes. The software is created for control of the photodetector modules, as well as the test bench for measuring their characteristics is designed.

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.