V. G. Ryskin

A new compact microwave spectroradiometer-ozonometer

A new-generation mobile microwave spectroradiometer intended for studying the Earth’s ozone layer is described. The device receives thermal radio-frequency emission of the stratospheric ozone at the frequency of its rotational transition (110 836 MHz) in a 240-MHz frequency band. The spectral resolution at the O3 line center is 1 MHz. The effective noise temperature of the uncooled receiver in the single-sideband mode is ∼2000 K. The ozonometer is equipped with a computer-aided data measurement, calibration, and preprocessing control system. The device is intended to obtain an ozone profile in a 20- to 60-km altitude interval within 15–20 min.

Variations in the concentration of mesospheric ozone during the total solar eclipse of March 29, 2006, from microwave radiometric data

We present the results of microwave observations of the ozone content variability in the upper stratosphere and lower mesosphere during a total solar eclipse of March 29, 2006 at the Kislovodsk high-altitude scientific station. An increase in the concentration of mesospheric ozone was recorded during the eclipse. At a height of 60 km, the ozone concentration increased by 40%, which is close to the value of diurnal ozone variations.

Response of mesospheric ozone to the heating of the lower ionosphere by high-power HF radio emission

We detected a decrease in the intensity of microwave radiation at the atmospheric ozone line at a frequency of 110836.04 MHz during ionospheric modification by high-power HF radiowaves radiated by the Sura Ionospheric Heating Facility. The obtained experimental data allowed us to hypothesize that this effect was caused by the fact that mesospheric ozone was affected by internal gravity waves generated in the E region of the ionosphere during its high-power HF radiowave heating.

First results of an integrated experiment on sounding the middle atmosphere in optical and millimeter wavelength ranges (over Tomsk)

Results of joint ground-based microwave and lidar measurements of ozone and temperature vertical profiles are presented. The importance of such observations for the study of the influence of different disturbances on the ozone layer is discussed. The results are compared with the MLS/AURA satellite data and model profiles.

On the behavior of stratospheric ozone in the western Arctic during the 2003–2004 winter and spring

We present the results of simultaneous measurements of variations in the ozone layer in the north-western Arctic conducted with the help of different instruments. It is shown that, in the winter of 2003–2004, when the stratosphere was relatively warm and the wave activity was high, spatial inhomogeneities in the field of ozone distribution were observed. For April 2004, we detect a decrease in the ozone content in the range of heights between 25 and 40 km. This decrease was recorded simultaneously by the HALOE, SAGE, and POAM satellite instruments.

Microwave and optical observations of ozone and temperature of the middle atmosphere during stratospheric warming in Western Siberia

We present the results of combined ground-based measurements of vertical ozone and temperature profiles with the use of microwave and lidar instrumentation during stratospheric warming. Marked variations in ozone concentration and temperature in the middle atmosphere are recorded during wintertime warming (December, 2012–January, 2013). The ozone concentration at altitude levels from 25 to 60 km increased by a factor of 1.5–2, with the amplitude of ozone variations substantially increased. The peak of the positive deviation of temperature from the monthly average value reached 70 K at a height of 30 km. The daily variations in ozone at a height of 60 km, associated with sunset and sunrise, were about 30%.

Evaluation of chemical ozone loss in the stratosphere over the Kola Peninsula in the 2002/2003 winter from microwave sounding data

From long-term observations of ozone evolution in the stratosphere of the Kola Peninsula in the 2002/2003 winter, the rates of chemical destruction of ozone and its net loss at isentropic levels of 530 K (an altitude of about 22 km) and 465 K (an altitude of about 19 km) ar evaluated with consideration for diabatic descent of air masses. These rates were −18.6±3.3 and −14.3±2.9 ppb/day and the net loss of ozone due to its chemical destruction over the period from December 1, 2002, to March 5, 2003, reached 1.77±0.33 ppm and 1.36±0.29 ppm, respectively. At the lower level, these data are in satisfactory agreement (to within measurement errors) with other measurements that were taken at that time. At a potential-temperature level of 530 K, the ozone loss in the 2002/2003 season evaluated from our data and from similar microwave measurements performed in Kiruna (Sweden) virtually coincides and testifies to the fact that the net loss increases with altitude. These inferences are inconsistent with the results obtained with the Match technique and the method of averaging over a vortex, which indicate that the ozone loss decreases with altitude. However, since polar stratospheric clouds were detected regularly in December and early January at levels up to 600 K or higher, it may be suggested that the ozone loss at these altitudes can be comparable to the values found for isentropic levels of 465 to 475 K.

Stratospheric ozone distribution features from the results of simultaneous ground-based microwave measurements in Nizhni Novgorod and Kyrgyzstan

Presented are the results of studying the ozone layer over Nizhni Novgorod and Central Asia using the ground-based millimeter wavelength range equipment. Carried out is the comparison of results of ground-based measurements with the EOS Aura MLS data. The difference in the ozone layer structure at stratospheric heights is revealed during the joint measurements at the mentioned points in November 2010. The analysis demonstrates that this difference is caused by the influence of the polar stratospheric vortex. Proceeding from the experience of similar researches, the conclusion is made on the necessity of organizing the permanent domestic network of the ground-based microwave monitoring of the ozone layer.

Microwave measurements of the ozone content in winter arctic stratosphere

As a result of the long-term observations lead in region of Kola Peninsula, connection between character of variations of the ozone content in a stratosphere of Arctic regions and behavior and structure of a winter polar vortex is established. During winter seasons with well developed cyclone and duration of stable existence not less than 1.5–2 months were observed extremely low ozone number density at heights 20–25 km connected, apparently, with its chemical destruction. On the other hand, during disturbances of the vortex, accompanied strong stratospheric warming, was registered almost double increase of ozone amount in a high-altitude interval from 20 up to 40 km. Comparison of results of ground-based microwave monitoring of an ozone layer to data of the satellite instrument EOS MLS installed on satellite AURA is lead. In most cases comparison has shown satisfactory within the limits of an error of measurements coincidence of results. However in conditions of atmospheric disturbances when arose significant spatial heterogeneity, the discrepancy of results of comparison was marked. The possible reasons which cause the detected disagreement in results are discussed.

Microwave observations of stratospheric ozone variations during a solar eclipse

During solar eclipses the ozone layer of the Earth is exposed to variable action of an ozone active radiation of the Sun (wavelengths 200-400 nm). The variations of magnitude and spectral structure of a solar ultraviolet radiation flow can cause both variability of total ozone content (TOC), and its vertical distribution. It is obvious, that the ozone variability should happen in the upper part of a layer (above than 40 km), where time of O/sub 3/ relaxation it is a little (photochemical time of life - about one minute). The ozone layer at altitudes of 40-80 km reacts most rapidly to variations of the Sun radiation, which are stimulated by rotation of the Earth (sunrise and sunset) and by solar eclipses. During eclipses the observations of TOC variations are carry out usually. The data of such observations represent rather inconsistent information about behavior of TOC to a phase of solar eclipses. It, most likely, is connected to that the full amount of ozone on heights exceeding 40 km, makes up only small part TOC. As to modifications of vertical distribution ozone density during eclipses, the information about them is not enough. The realization of similar observations has become possible due to emerging and development, perhaps, most approaching tool for research of the response of the upper atmosphere ozone on a rather rapid modification of the solar radiation - microwave radiometry with a high temporal and spectral resolution. We briefly present a method of research of ozone variations during a partial solar eclipse of May 31, 2003 (maximum phase about 70%), and discuss the used equipment and obtained outcomes.