В работе приведены результаты лазерного зондирования атмосферы над акваторией озера Байкал, полученные в ходе регулярных летних экспедиций. Анализ накопленных с использованием лидаров серии «ЛОЗА» данных, совместно с информацией об изменении метеопараметров атмосферы во время экспериментов, позволил исследовать пространственно-временную изменчивость вертикальной структуры аэрозоля в различных атмосферных условиях. The paper presents the results of laser sensing of the atmosphere over the water area of Lake Baikal, obtained during regular summer expeditions. The analysis of the data accumulated using lidars of the LOZA series, together with information on changes in atmospheric meteorological parameters during experiments, made it possible to study the spatiotemporal variability of the vertical structure of the aerosol in various atmospheric conditions. laser sounding of the atmosphere, Lake Baikal water area, vertical structure of aerosol, spatiotemporal variability

Рассмотрены результаты самолетных лидарных измерений пространственного распределения концентрации фитопланктона в поверхностных водах Карского моря. Содержание фитопланктона определяется методом лазерно-индуцируемой флуоресценции фотосинтезирующего пигмента – хлорофилла «а». Интенсивность сигналов флуоресценции нормировалась на интенсивность сигналов комбинационного рассеяния излучения воды. Результаты пространственного распределения нормированной интенсивности флуоресценции получены для трех участков Карского моря. Для двух участков моря пространственное распределение фитопланктона достаточно однородное с коэффициентами вариации меньше 15%. Третий участок характеризуется мощным влиянием материкового речного стока, что проявляется в наличие фронтальных зон, где коэффициент вариации распределения достигает 40%. Преимущественный вклад в эти вариации значений нормированной интенсивности флуоресценции вносит изменчивость сигналов комбинационного рассеяния в воде. This paper presents the results of aircraft lidar measurements of the spatial distribution of phytoplankton concentration in the surface waters of the Kara Sea. The phytoplankton content is determined using the laser-induced fluorescence method of the photosynthetic pigment - chlorophyll "a". The intensity of fluorescence signals is normalized to the intensity of the combined scattering signals of water radiation. Results of the spatial distribution of normalized fluorescence intensity are obtained for three sections of the Kara Sea. For two sections, the spatial distribution of phytoplankton is quite homogeneous with variation coefficients of less than 15%. The third section is characterized by a strong influence of continental river runoff, manifested in the presence of frontal zones, where the variation coefficient of the distribution reaches 40%. The predominant contribution to these variations in normalized fluorescence intensity is made by the variability of the combined scattering signals in the water.

The spatial structure of atmospheric aerosol over Baikal in summer is studied on a regular basis with the use of ground-based LOSA-M2 lidar measurements at the Boyarsky scientific station of the Institute of Physical Material Science, Siberian Branch, Russian Academy of Sciences (51.83 degrees N, 106.06 degrees E, 456 m a.s.l.), Republic of Buryatia, Russia. The lake is located in a basin surrounded by mountain ranges on all side; its water volume is large. The lidar data are analysed along with the regional meteorological situation and meteorological parameters of the atmosphere. The daily dynamics of aerosol distribution over the atmospheric is examined for the period from 2015 to 2023 accounting the effect of different air masses in the region. Three main typical air circulation types are identified for the coastal zone of southern Baikal in summer, which determine the atmospheric aerosol generation and transport. The first and most common type relates to breeze circulation, where the main changes in the spatial structure of aerosol occur in the 2-3-km layer and are determined by changes in the transport direction within a breeze cell during the day. The main feature of this type is a decrease in the altitude of an air layer which contains most of aerosol in the lower atmosphere up to 1 km. The second type refers to southwestern transport under the presence of an anticyclone over the region. The maximal altitude of the aerosol layers attains 7 km in this case. The most complex and dynamic changes in the daily spatial structure of atmospheric aerosol occurred under transport of cyclones and associated atmospheric fronts over Lake Baikal. Under this third type, the altitude of the aerosol layers decreases throughout the day within the altitude range from the surface to 3-4 km.

В докладе приводятся результаты наблюдений горизонтально ориентированных кристаллических частиц в облаках верхних ярусов с помощью сканирующего поляризационного лидара ЛОЗА-М3 в 2018-2023 гг. В слоях с выраженным зеркальным отражением зависимость интенсивности сигнала от угла наклона отражает распределение отклонения частиц относительно горизонтальной плоскости и описывается экспоненциальной зависимостью. Показано влияние температуры облака на ширину распределения. Описаны случаи наблюдения зеркального отражения от одиночных частиц. The report presents the results of observations of horizontally oriented crystalline particles in the clouds of the upper tiers using the scanning polarization lidar LOZA-M3 in 2018-2023. In layers with pronounced specular reflection, the dependence of the signal intensity on the angle of inclination reflects the distribution of particle deflection relative to the horizontal plane and is described by an exponential dependence. The influence of cloud temperature on the distribution width is shown. Cases of observation of specular reflection from single particles are described.

В работе приведены результаты лазерного зондирования атмосферы над акваторией оз. Байкал в летней экспедиции 2023 г. На основе данных полученных с использованием лидара «ЛОЗА-А2», исследована пространственно-временная изменчивость вертикальной структуры аэрозольных полей. Это позволяет выявить особенности формирования и переноса атмосферного аэрозоля в данном регионе. The paper presents the results of laser sounding of the atmosphere over the water area of Lake Baikal during the summer expedition of 2023. Based on the data obtained using the “LOZA-A2” lidar, the spatiotemporal variability of the vertical structure of aerosol fields is investigated. This allows us to reveal the features of the formation and transport of atmospheric aerosols in this region.

Представлены результаты синхронных лидарных наблюдений переноса аэрозольных полей атмосферы над оз. Байкал в летней экспедиции 2018 г. Эксперимент проводился с использованием двух лидаров, один из которых располагался на судне, а второй - на стационаре, на удалении 732 м от судна. На основе корреляционного анализа полученных данных сделаны оценки времени переноса атмосферных аэрозольных неоднородностей между точками наблюдений на разных высотах над горной котловиной. Выявлено, что для высотного диапазона 100-350 м время переноса составляет 5 мин 20 с, для 1250-1500 м - 7 мин 12 с, для 2100-2500 м - 5 мин 20 с и для диапазона 4200-4300 м - 6 мин 24 с. Подобное неравномерное высотное распределение времени переноса аэрозольных объектов обусловлено сложным механизмом циркуляции воздушных потоков в горной котловине. The results of synchronous lidar observations of the transfer of atmospheric aerosol fields over Lake Baikal during the summer expedition of 2018 are presented. The experiment was carried out using two lidars, one of which was located on a ship, and the second, at a distance of 732 m at a stationary station. Based on the correlation analysis of the lidar data, the transfer time of atmospheric aerosol heterogeneities between observation points at different altitudes above the mountain basin is estimated. It is found that the transfer time is 5 min 20 s for the altitude range 100-350 m, 7 min 12 s for 1250-1500 m, 5 min 20 s for 2100-2500 m, and 6 min 24 s for the range 4200-4300 m. Such uneven altitude distribution of the transfer time of aerosol objects is due to the complex air flow circulation in the mountain basin.

The results of the modernization of the mobile aerosol Raman lidar LOZA-A2 are presented. Lidar measures purely rotational Raman scattering signals simultaneously with measurements of the vibrational component of spontaneous Raman scattering of lidar signals. The technique for interpreting Raman lidar sensing data is considered. Data are obtained from simultaneous measurements of vibrational–rotational and purely rotational Raman scattering in atmospheric sensing over the Lake Baikal. The results are presented from retrieving the vertical profiles of the optical characteristics of the atmosphere at a wavelength of 532 nm using these data.

В малогабаритных мобильных лидарах преимущественно применяется одночастотное зондирование с регистрацией упругого обратно рассеянного излучения на аэрозолях. Для корректного восстановления оптических характеристик аэрозоля используются аэрозольно-рамановские лидары. Наиболее распространённый в таких лидарных измерениях для оценки оптических свойств является метод регистрации колебательного комбинационного рассеяния на молекулах азота. Недостатки этого метода в низком сечение обратного рассеяния и значительным частотным сдвигом рамановской колебательной компоненты. Эти проблемы решаются за счет использования чисто вращательного рамановского рассеяния, который характеризуется более высоким сечением обратного рассеяния, и значительно меньшим сдвигом частоты, что практически убирает зависимость от показателя Ангстрема. В докладе представлена практическая реализация вращательных рамановских измерений в мобильном лидаре «ЛОЗА-А2».

The paper discusses the results of the analysis of experimental data on the study of the atmosphere in the summer over the water area of the Lake Baikal. In recent years, ship measurements have been continued, using the research vessel “Academician V.A. Koptyug”, the route of which runs along the entire lake. Regular observations are carried out using lidars (LOSA-M2 and LOSA-A2), as well as local devices (gas analyzers). Additionally, satellite data and information on meteorological parameters of the atmosphere are used during experiments. The results of changes content atmospheric aerosol and ground-level gas impurities in the atmosphere over Lake Baikal in background conditions and during forest fires are shown.

Between 2011 and 2017 complex experiments on lidar sounding of the atmosphere were conducted on the territory of Akademgorodok (Tomsk, 56°28'N, 85°E), accompanied by the launch of meteorological balloons. A total of 45 radiosonde sessions were conducted using Vaisala R92SGP radiosondes in the daytime and at night. WE compared the vertical moisture profiles and the profiles of backscattering coefficient. In most cases aerosol layers are present at altitudes where a local increase in relative humidity is observed. However, in 10 cases out of 45, the location of the aerosol layers on the records does not coincide with the position of the wet layers. The report provides several examples of such records, discusses the possible conditions for the occurrence of such phenomena.

The report presents the results of a comprehensive experiment on the study of the atmosphere over Lake Baikal, which was carried out in July - August 2019. Remote investigation of aerosol content in the troposphere was carried out using mobile lidars. One of the lidars was installed on board the research vessel «Academician Koptyug». The route of the vessel covered the entire water area of the lake. The second lidar for the entire duration of the experiment was located on the southeastern shore of Lake Baikal. The period of the experiment coincided with extensive forest fires in Eastern Siberia. The lidar data made it possible to reconstruct the spatiotemporal distribution of the smoke aerosol over the Baikal water area and estimate its optical depth, the values of which, in extreme cases, reached up to τ ≈4.

The methodology for integrated ground-based and satellite monitoring of atmospheric aerosols is discussed. An algorithm for processing data from coordinated lidar and radiometric sensing (LRS) is described. The algorithm was tested by studying aerosol parameter altitude profiles in the vicinity of AERONET stations using data from ground-based solar radiometers and CALIOP satellite lidar. Coordinated measurements with AERONET network radiometers and ground-based multiwavelength lidars at remote sensing stations of the Institute of Physics, NASB (Minsk, Belarus), Institute of Atmospheric Optics, SB, RAS (Tomsk, Russia), and KRSU (Teploklyuchenka, Kyrgyzstan) were used to verify the satellite sensing results.

The article presents the results of observations of the crystalline cloud polarization structure carried out in Tomsk in April-October 2018. Scanning lidar LOSA-M3 makes it possible to measure the polarization characteristics of backscattering signals from aerosol and clouds at wavelength 532 and 1064 nm. Zenith scanning was carried out at a rate of 0.5 degrees per second, which corresponds to a shift in the direction of sounding by 2 minutes between laser pulses. The results show that the degree of horizontal orientation of the particles can vary significantly in different parts of the cloud. The dependence of the scattering intensity on the inclination angle is well described by the exponential dependence. The values of cross-polarized component in most cases shows a weak decline with the angle, but its change are smaller than the measurement errors. We can conclude that it is practically independent on the inclination angle. The scattering intensity at a wavelength of 532 nm has a wider distribution than at 1064 nm.

The paper presents the results of regular annual experimental studies of the atmosphere in summer over Lake Baikal. The observations were carried out with the help of the LOSA-M2 lidar located in the background area at the Boyarsky stationary site, in the south-eastern part of the lake. In the expedition of 2018, additional measurements were simultaneously carried out by the lidar "LOZA-A2" installed on the scientific-research vessel "Akademik V.A. Koptyug". The route of the vessel passed through the whole lake. The results of changes in the spatial structure of atmospheric aerosol fields in background conditions and during forest fires are shown.

A description of a complex optical experiment using the means of remote laser sensing and local control for researching the physical processes of the formation of aerosol fields of the atmospheric boundary layer is presented. Examples of joint atmospheric sounding using ground-based and space-based lidars (CALIPSO lidar), as well as ground-based lidarphotometric studies are given. The technique of processing lidar-photometric data during the recovery of optical and microphysical parameters of atmospheric aerosol, including the recovery of vertical profiles, is discussed.

Scanning polarization lidar LOSA-M3 is designed to study of the optical characteristics of crystal clouds of the upper and middle layers at two wavelengths - 532 and 1064 nm. Lidar allows you to smoothly change the angle of inclination from the vertical with simultaneous conical (azimuthal) scanning. Such a measurement scheme makes it possible to study in detail the preferential orientation of ice crystals in the clouds. The lidar simultaneously measures the polarization characteristics of signals for linear and circular initial polarizations, which allows to obtain additional information about the anisotropy of scattering particles, including exploring the azimuthal orientation of the particles. The first results of observations of the crystalline cloud polarization structure carried out in Tomsk in April-October 2018 are presented in the article. The results show that the contribution of horizontally oriented particles giving a specular reflection can vary significantly in different parts of the cloud.

We present the results of complex experimental studies of gas admixtures and the vertical structure of aerosol in the atmosphere over the Lake Baikal in July 2018 onboard research vessel Academician V.А. Koptyug . Simultaneously, the observations were performed at the Boyarsky stationary station, located in the southeastern part of Lake Baikal. We describe briefly the instrumentation used in the experiments and discuss certain preliminary results of analyzing the data obtained.

The development of the scientific, methodological and technical basis for an integrated terrestrial and satellite monitoring of the atmosphere and the Earth's surface over the Eurasian continent is the goal of an international project carried out by the scientific organizations of Belarus, Russia, Mongolia and Vietnam with the support of the Eurasian Association for the Support of Scientific Research (EAPS). The report presents the results of testing the method of coordinated terrestrial and satellite, lidar and radiometric measurements to study altitude profiles of aerosol parameters in the areas of AERONET stations in the countries participating in the project. The data of the satellite lidar CALIOP and the solar radiometer were processed by the algorithms developed in the frame of combined lidar and radiometric sounding technique (LRS). Coordinated multiwavelength lidar measurements were carried out at remote sensing stations in IPNASB (Minsk, Belarus), IAO (Tomsk, Russia) and KRSU (Teplokluchenka, Kyrgyzstan) to validate the results of satellite data processing.

Scanning lidar LOSA-M3 makes it possible to measure the polarization characteristics of backscattering signals from aerosol and clouds at wavelength 532 and 1064 nm. The lidar transceiver is placed on a scanning column, which allows to change the direction of sounding within the upper hemisphere at a speed of 1 degree per second. The polarization characteristics of the transmitter (linear or circular polarization) can be changed by rotating the phase plates synchronously with the laser pulses. Conical scanning of the lidar allows identifying cloud areas with preferential zenith or azimuthal orientation of the crystal particles. The article presents the results of observations of the cloud polarization structure carried out in Tomsk.