Sergey I. Dolgii

A differential-absorption lidar for ozone sensing in the upper atmosphere-lower stratosphere

At the Siberian Lidar Station of the Zuev Institute of Atmospheric Optics (Tomsk) (56.5°N, 85.0° E), a lidar has been developed for measuring the vertical distribution of ozone in the upper troposphere-lower stratosphere in order to study the ozone dynamics in the tropopause region and the troposphere-stratosphere exchange. In sensing performed by the method of differential absorption and scattering, a pair of wavelengths of 299/341 nm is used, which correspond to the first and second Stokes components of converted radiation of the fourth harmonic of the pumping radiation from a Nd:YAG laser (266 nm) on the basis of the effect of stimulated Raman scattering in hydrogen.

Lidar Observations of Aerosol Disturbances of the Stratosphere over Tomsk (N; E) in Volcanic Activity Period 2006–2011

The lidar measurements (Tomsk: N; E) of the optical characteristics of the stratospheric aerosol layer (SAL) in the volcanic activity period 2006–2011 are summarized and analyzed. The background SAL state with minimum aerosol content, observed since 1997 under the conditions of long-term volcanically quiet period, was interrupted in October 2006 by series of explosive eruptions of volcanoes of Pacific Ring of Fire: Rabaul (October 2006, New Guinea); Okmok and Kasatochi (July-August 2008, Aleutian Islands); Redoubt (March-April 2009, Alaska); Sarychev Peak (June 2009, Kuril Islands); Grimsvotn (May 2011, Iceland). A short-term and minor disturbance of the lower stratosphere was also observed in April 2010 after eruption of the Icelandic volcano Eyjafjallajokull. The developed regional empirical model of the vertical distribution of background SAL optical characteristics was used to identify the periods of elevated stratospheric aerosol content after each of the volcanic eruptions. Trends of variations in the total ozone content are also considered.

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).

Algorithm for retrieval of vertical distribution of ozone from DIAL laser remote measurements

We present an algorithm for retrieval of vertical distribution of ozone with temperature and aerosol correction during DIAL lidar sounding of the atmosphere. Most suitable wavelengths for measurements of ozone profiles in the upper troposphere—lower stratosphere are selected. Results of lidar measurement at wavelengths of 299 and 341 nm agree with model estimates, which point to acceptable accuracy of ozone sounding in the 6–18 km altitude range.

Optical monitoring of characteristics of the stratospheric aerosol layer and total ozone content at the Siberian Lidar Station Tomsk: 56° 30′ N; 85° E

We consider the results of long-term remote optical monitoring obtained at the Siberian Lidar Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (56° 30′ N, 85° E). The scattering characteristics of stratospheric aerosol layer, obtained according to data of lidar measurements recorded since 1986, are presented. We analyse the trends of changes in the total ozone (TO) content over Tomsk for the period 1996–2013 according to data of spectrophotometric measurements employing Total Ozone Mapping Spectrometer (TOMS) data for the period 1979–1994. We determined the periods of elevated content of stratospheric aerosol over Tomsk after a series of explosive eruptions of volcanoes in the Pacific Ring of Fire and Iceland in 2006–2011. Since the second half of the 1990s we have recorded an increasing TO trend, equalling 0.65 DU/year for the period 1996–2013.

Traces of eruption of Eyjafjallajökull volcano according to data of lidar observations in Tomsk and Surgut

We present the results of lidar measurements of the vertical distribution of optical parameters of anomalous aerosol formations in the atmosphere and the polarization state of backscattered sounding radiation, obtained in Tomsk (56.48°N; 85.05°E) and Surgut (61.25°N; 73.43°E) in April–May 2010. Data from measurements using back trajectory analysis of atmospheric air-mass transport according to the NOAA HYSPLIT MODEL showed that the observed anomalous aerosol formations were due to transport of the products of the Eyjafjallajökull volcano eruption in Iceland (April 14, 2010). First traces of the volcanic eruption were recorded in the troposphere over Tomsk on April 19. The volcanic aerosol persisted in the troposphere for about 10 days in total; it penetrated into the stratosphere insignificantly and could not have noticeable long-term radiation and thermal effects.

A three-frequency Lidar for sensing microstructure characteristics of stratospheric aerosols

A three-frequency lidar developed at the Siberian Lidar Station of the Zuev Institute of Atmospheric Optics (Siberian Branch, Russian Academy of Sciences) at Tomsk (56.5° N, 85.0° E) is described. The lidar is intended for sensing the microstructure characteristics of stratospheric aerosol at wavelengths of 355, 532, and 683 nm, which are, respectively, the third and second radiation harmonics of a Nd:YAG laser and the first Stokes component of conversion of laser radiation at a wavelength of 532 nm in hydrogen on the basis of the stimulated Raman scattering (SRS) effect. Knowledge of microstructure characteristics of the stratospheric aerosol is necessary for studying its influence on the radiation-temperature and chemical balance of the entire atmosphere. Some results of full-scale lidar measurements are presented.

Intercomparison of Ozone Vertical Profile Measurements by Differential Absorption Lidar and IASI/MetOp Satellite in the Upper Troposphere–Lower Stratosphere

This paper introduces the technique of retrieving the profiles of vertical distribution of ozone considering temperature and aerosol correction in DIAL sounding of the atmosphere. The authors determine wavelengths, which are promising for measurements of ozone profiles in the upper troposphere–lower stratosphere. An ozone differential absorption lidar is designed for the measurements. The results of applying the developed technique to the retrieval of the vertical profiles of ozone considering temperature and aerosol correction in the altitude range 6–15 km in DIAL sounding of the atmosphere confirm the prospects of ozone sounding at selected wavelengths of 341 and 299 nm with the proposed lidar. The 2015 ozone profiles retrieved were compared with satellite IASI data and the Kruger model.

Aerosol disturbances of the stratosphere after eruption of Grimsvötn volcano (Iceland, May 21, 2011) according to observations at lidar network stations of CIS countries CIS-LiNet in Minsk, Tomsk, and Vladivostok

In 2010 and first half of 2011, a background aerosol content was observed in the atmosphere of the Northern Hemisphere midlatitudes. The report presents the observations of aerosol disturbances of the stratosphere in the second half of 2011, which were performed at lidar network stations of CIS countries CIS-LiNet in Minsk (53.9°N; 27.6°E), Tomsk (56.5°N; 85.0°E), and Vladivostok (43.0°N; 131.9°E). Data of lidar measurements at the sensing wavelengths of 353, 355, and 532 nm indicate that increased aerosol content was observed since June – July almost until the end of 2011 in the lower stratosphere up to the altitudes ~ 18 km. A well-defined, temporally stable aerosol layer was observed until October 2011 in the altitude interval ~ (13-17) km. The trajectory analysis of air mass transport in the stratosphere according to NOAA HYSPLIT MODEL with employment of CALIPSO satellite data shows that the increased aerosol content observed was most likely due to transport of eruption products of Grimsvötn volcano (May 21, 2011, Iceland: 64.4°N; 17.3°W).

Lidar system for measurement of vertical profiles of ozone in the upper troposphere-stratosphere

A lidar for DIAL measuring the vertical distribution of ozone at the wavelengths 299/341 nm and 308/353 nm is presented. The wavelengths used allow monitoring of vertical stratification of ozone within the upper troposphere - stratosphere. The results of lidar ozone sensing are given in comparison with the IASI/MetOp and MLS/AURA satellites. The results of comparison of the reconstructed profiles of the vertical distribution of ozone with allowance for temperature and aerosol correction confirm the prospects of using the complex of the ozone probing wavelengths of 299/341 nm and 308/353 nm. The results of the comparison show a high accuracy of ozone concentration measurements in the altitude range of 5 to 45 km.