ANALYTICAL REVIEW
Topics of investigations performed in Russia in the field of atmospheric radiation are well described by session contents of International Symposium of former USSR countries on Atmospheric Radiation (ISAR-02) held in St. Petersburg in June 18-21 2002. Therefore let us analyze the state-of-the art and tendencies of this current of science in according with the Symposium Program.
The Symposium Program involved 8 Sessions. Plenary Session (Yu.M. Timofeyev, SPbSU, Chairman) included 8 papers covering the complete specter of scientific treatments in the field of atmospheric radiation. Report of T.A. Sushkevich (IAM RAS) was devoted to the historical review of achievements of soviet scientists in the field of remote (first, space) sensing of the environment. N.E. Chubarova (MSU) reported Russian state-of-the art in UV ground-based and satellite monitoring. Special attention was given to the problem of monitoring error and its determination. G.I. Gorchakova with colleagues presented the review of ground-based and aircraft studies of aerosol microphysical and optical properties which have been conducted in OIAP RAS. Results of the numerous measurements by different instruments in different Russian regions were given and analyzed. Report of V.N. Osipov (ITOES, Sosnovy Bor) was dedicated to problems and methods of developing the high-temperature databases of fine structure parameters for H2O and NO2 absorption bands. Special attention was focussed on analyzing the accuracy of the database information and comparing with the HITRAN. Invited report of V.E. Kunitsyn (MSU) was the review of recent state in the field of radio-tomography of parameters of upper atmosphere and near space. The author presented some interesting results of the study of ionospheric characteristics which was performed during last years within the framework of international projects and estimated possibilities of radio-tomography for studying the tropospheric parameters (in particular, for retrieving the water vapor content). Yu.A. Borisov with colleagues (CAO) gave the review of information possibilities of the SAGE-III instrument launched onboard Russian satellite â "Meteor-3M" in December 2001. The authors described different â (spectral, angular, etc.) instrument characteristics and results of studying the potential accuracy of retrieving the different atmospheric characteristics (O2, NO2, H2O content, aerosol extinction, etc.). In comparison with previous SAGE-II satellite experiment, the SAGE-III experiment makes it possible to measure in larger number of spectral channels and to use solar radiation reflected by the Moon for measurements. Detailed review of the GOME space experiment was given by V.V. Rozanov (SPbSU) with colleagues from German Bremen University. This experiment has been conducted onboard ERS-2 since 1996 and now there are a huge amount of the information on global fields of O2, NO2, H2O content, atmospheric aerosol and cloud characteristics, etc. Examples of the validation and analysis of space measurement data were given. At the end of the report the brief information on new space SCIAMACHI experiment that is a continuation of the GOME experiment was given. L.R. Dmitrieva-Arrago (RHMC) analyzed recent state of the problem of developing the algorithms for radiation transfer computation in weather and climate numerical models. Special attention was given to aerosol optical characteristics, their parametrization and the aerosol influence on the radiation transfer in Earth atmosphere.
Session 1 - Radiative Transfer Theory “New Developments (Co-chairmen - T.A. Germogenova, IAM RAS and A.P. Ivanov, IP BAS). 16 reports were presented at this Session. 9 papers were oriented on developing the effective algorithms and codes for the mathematical simulation of radiation transfer in tasks with complex three-dimensional geometric models:
New results in the theory and numerical simulation of polarized radiation transfer were presented in some reports:
On the whole reported papers testify to the essential amplification of possibilities of mathematical modeling in problems of atmospheric optics and the range of considered applied tasks. Some new approaches to the analysis of multi-dimensional problems of the theory of radiative transfer have been developed.
Session 2 - Radiation Climatology (Co-chairmen - O.M. Pokrovsky, MGO and N.E. Chubarova, MSU). The Session includes 14 oral reports and 8 posters.
A number of papers were devoted to the comparison of calculations and measurements of short-wave solar radiation in cloudless atmosphere in different geographical regions (A.N. Rublev et al., RSC (Curchatov Institute); N.N. Ulyumdzhieva et al., MSU). Analysis of inter-year variability of radiation fluxes and important atmospheric parameters - surface albedo, atmospheric aerosol characteristics - was presented by E.L. Makhotkina, O.M. Pokrovsky, MGO; G.M. Abakumova and E.V. Gorbarenko with colleagues, MSU; E.I. Torez, TNU).
Global decrease of atmospheric aerosol turbidity has been noted. Importance of taking into account the impact of the orientation of ice hexagonal prisms on the solar radiation was discussed by A.G. Petrushin (IEM SPA "Typhoon"). V.I. Korzov et al. (MGO) has compared satellite and ground-based solar radiation measurements.
A number of papers were dedicated to investigations of UV-radiation. I.P. Terenetskaya (IP BAS) analyzed the bio-activity of UV-radiation; A.F. Nerushev and N.V. Tereb (IEM SPA "Typhoon") gave results of comprising the satellite and ground-based measurements of bio-active UV-radiation near Obninsk.
Analysis of the impact of the ozone layer depletion on the increase of surface UV-irradiance is among the important lines of inquiry in radiation climatology. Possible interaction of near-surface ozone and UV-B radiation was discussed by B.K. Roldugin et al. (PGI RAS), A.Yu. Yurova and N.E. Chubarova (MSU). Report of G.N. Nikolsky dedicated to the impact of optical radiation from facula structures which was revealed during independent measurements by several instruments was widely discussed.
Session 3 - Radiation and Cloud/Aerosol - Theory and Measurements (Co-chairmen - G.I. Gorchakova, OIAP RAS and I.L. Karol, MGO). The Session included 8 oral reports and a number of posters, which treated results of measurements and simulation of the interaction of radiation with clouds and aerosol.
E.I. Nezval' (MSU) reported results of measuring the UV, photosynthetically active and integral solar radiation under conditions of cumulus clouds. In a number of papers of IAO SB RAS, results of modeling the aerosol solar radiation extinction in different atmospheric layers depending on the Sun position and atmospheric conditions have been given (V.V. Belov, S.M. Sakerin, T.B. Zhuravleva et al.). Yu.I. Belikov (IAG) has studied the radiation scattering in twilight polar atmosphere. Papers of scientists of RRPI (A.V. Troitsky, A.M. Osharin) were devoted to the microwave radiation transfer in clouds and snowfall.
Posters of scientists of different institutes (IEM SPA "Typhoon", SPbSU, IAO SB RAS, SPb branch of IO RAS) demonstrated results of measurements and methods of retrieving the aerosol optical characteristics, the influence of atmospheric factors on radiation fluxes under different conditions, etc.
In the course of discussion, actual directions in the field of the interaction of radiation with clouds and aerosol have been determined:
Session 4 - Atmospheric Molecular Spectroscopy (Co-chairmen - M.V. Tonkov, SPbSU; V.N. Arefyev, IEM SPA "Typhoon"; and V.M. Osipov, ITOES). There were 16 oral reports and 5 posters. Studies in atmospheric spectroscopy conducted in the CIS countries were represented at ISAR-02 more widely then at ISAR-99.
Reports dedicated to developing a number of new informative-computational systems and databases on spectroscopic and photochemical parameters of atmospheric gases exited common interest (the reports of IOA SB RAS, SOI, ITOES). In a number of cases, these databases are Internet-accessible and give a possibility not only to get an information but also to calculate a number of spectral characteristics (absorption coefficients, transmittance functions and etc.).
In this connection the problem of objective estimate of the accuracy of proposed algorithms arises and B.A. Fomin and T.A. Udalova (RSC "Curchatov Institute" stated such problem. As was noted, the most essential problems in calculating the spectra originate in rather deficient representation of the information on continual absorption in these databases. Similar discussion was continued by M.V. Tonkov, N.N. Filippov, SPbSU; V.F. Golovko and O.B. Rodimova et al., IOA SB RAS. But these problems are ill-developed and the results can not be included in databases. Evidently, it would be efficient to solve this problem by collective efforts in the framework of the section of atmospheric spectroscopy of Russian Commission on Atmospheric Radiation (RCAR).
A number of papers were dedicated to spectroscopic studies of concrete systems (V.V. Parshin et al., IAP RAS; M.V. Buturlimova et al., SPbSU). In the first paper, the sensitivity and accuracy of measuring the line parameters exceed the world level by about an order. Kinetics of molecular excitation in atmosphere due to collisions and radiative transfer have been studied by V.A. Yankovsky with R.O. Manuilova and G.M. Shved et al., SPbSU.
Session 5 - Satellite Meteorology (Co-chairmen - A.B. Uspensky, SRC SM "Planeta" and Yu.A. Borisov, CAO). 8 oral and 12 posters were presented at the Session. Two papers of Nansen Center were dedicated to the use of satellite active and passive microwave measurements for ice monitoring. Methods of using the AVHRR data for the detection of wildfire were discussed by scientists of IAO SB RAS. G.M. Kruchenitsky (CAO) and D.V. Ionov et al. (SPbSU) analyzed the TOMS data of satellite sounding of total ozone content and performed the comparison with data of CIS ground-based ozone network. V.D. Stepanenko at al. (MGO) discussed methods of using the information from METEOSAT and "Meteor-3M" in numerical models of the convective cloud transformation. A.F. Nerushev et al. (IEM SPA "Typhoon") considered approaches to the estimation of parameters of atmospheric vortexes from satellite data.
Posters concerned different aspects of using the satellite information for remote sensing of parameters of the atmosphere and underlying surface. Scientists of MGO and SRC SM "Planeta" represented results of methodical studies dedicated to using the information of microwave sounder "Meteor-3M–1 and NOAA information for remote sensing of atmospheric parameters. Interesting results on remote determination of trace gas concentrations from the GOME data were contained in papers of scientists of SPbSU. Methodical work of SPbSU authors was dedicated to estimating the accuracy of occultation methods of determining the atmospheric gaseous and aerosol content.
In discussion, it was noted that the most of represented investigations based on using the information from foreign space systems. In this context, at next ISAR it would be very useful to present state-of-the art and perspectives of space observing system in Russia and CIS. In addition, it was noted the absence of reports dedicated to such traditional areas of satellite meteorology as the estimate of cloud parameters, remote determination of wind vector, etc.
Session 6 - Remote Sensing of the Atmosphere and Underlying Surface in Different Spectral Ranges (Co-chairmen - Yu.M. Timofeyev, SPbSU; G.G. Shchukin, MGO; V.E. Kunitsin, MSU; B.G. Kutuza, IRE RAS). More than 50 scientists participated in the Session work.
The Session topics covered the remote sensing of the stratosphere and atmospheric trace gases in visible, IR and microwave spectral ranges and different problems of measuring the cloud atmosphere and underlying surface and determining the geophysical parameters. Authors of 20 reports considered these problems.
Problems and results of studying the ozonosphere remote sensing were discussed in a number of original reports dedicated to the ozone variability in polar latitudes (A.M. Zvyagintsev, G.M. Kruchenitsky, CAO), the variations of atmospheric ozone in different latitudes (Yu.Yu. Kulikov et al., IAP RAS), the development of retrieving the ozone profile from spectral optical and microwave measurements (S.B. Rozanov et al., LPI RAS; D.N. Mukhin et al., IAP RAS; Ya.A. Virolainen, SPbSU with S. Bakan, Hamburg, Germany).
There were presented new data on sounding the CO2 and H2O atmospheric total content (V.N. Arefyev, IEM SPA "Typhoon"), the results of long-term measurements of CH4, CO and N2O over Central Russia (E.I. Grechko et al., OIAP RAS) and the estimates of temporal variability of trace gas content performed by scientists of different institutes (OIAP RAS, RSC "Curchatov Institute", SPbSU, IAO SB RAS).
In reports dedicated to different aspects of remote sensing, there were presented data of hydrological state of river headwaters obtained from satellite multi-spectral measurements (A.B. Uspensky, E.V. Volkova, SRC SM "Planeta"; V.V. Melentyev et al., Nansen Center), results of measuring the atmospheric and cloud moisture content (I.V. Samsonov, Nansen Center) and albedo of aerosol singleâ-scattering (M.A. Sviridenkov et al., OIAP RAS), data on global distribution of temperature and CO2 content in upper atmosphere (V.S. Kostsov et all., SPbSU).
During a discussion the following directions of remote sensing (including the satellite one) were estimated as the most perspective:
Session 7 - Radiation Algorithms in the Models for Forecasting the Weather and Climate (Chairmen - L.R. Dmitrieva-Arrago, RHMC and P.V. Sporyshev, MGO). Scientists from MGO, MSU, SPbSU, RHMC, Bremen University (Germany), OIAP RAS et al. participated in the Session work with 5 oral reports and 2 posters.
Three papers were dedicated to radiation algorithms (P.V. Sporyshev, MGO; M.V. Shatunova, RHMC; E.V. Rozanov (WRC)). P.V. Sporyshev has analyzed recent radiation algorithms being a part of hydrodynamic climate models that participated in the AMIP model comparison. Calculations of radiative balance budgets at atmospheric boundaries with 17 models developed by different world research centers during 1979-1995 were analyzed. The analysis demonstrated that the climatic models described the radiative balance budgets with fair accuracy. M.V. Shatunova proposed a new algorithm for describing the interaction of solar radiation with large-scale clouds. The algorithm takes into account microphysical properties of condensed, compound and crystal clouds - the mean radius of particle size distribution, the concentration and water (ice) content. Numerical experiments with changing the microphysical parameters demonstrated the influence of those on radiation characteristics of model atmosphere. E.V. Rozanov analyzed requirements to radiation algorithms of atmospheric models, which included the mechanism of photochemical transformations.
I.A. Gorchakova et al. (OIAP RAS) and V.A. Frol'kis et al. (MGO) have analyzed the problem of climate changes due to anthropogenic gases and continental aerosol. It was demonstrated that these factors effected climate rather significantly.
Posters illustrated the processes that are important for modeling the atmospheric phenomena with different temporal and spatial scales. T.B. Zhuravleva et al. (IAO SB RAS) represented the model of radiation transfer under broken cloud condition. The model includes a database with principal cloud parameters - the optical depth, the cloud amount, the cloud characteristic horizontal dimension, etc. Long-term forecasting of Earth climate in 21 century and regional after-effect for East Europe due its change was presented by S.V. Horozov et al. ("Hsoft" Ltd, Murmansk) and V.S. Belogolov (MTU). The forecast was worked out on the basis of thermo-balance model of atmosphere-hydrosphere and the global annual average of near-ground temperature and with taking into account the processes in upper atmospheric layers. The main model components are long measurement sets of Wolf-numbers and multi-year observations of global temperature annual average. The authors forecast that the global warming in the first part of 21 century will give way to the global cooling. In the forecast of the regional after-effect, authors used the analogy with the glaciating processes in Europe in 15-18 centuries.
Session 8 - Instrumentation for Measuring the Atmospheric Radiation Characteristics and Remote Sensing of the Atmosphere and Underlying Surface (Co-chairmen - V.V. Ivanov, LPI RAS; N.F. Elansky, OIAP RAS; V.I. Salin, SOI; Yu.A. Sklyarov, SSU).At Session 8 there were presented 13 reports. Special attention was given to reports connecting with developing the onboard apparatus for remote sensing from aircarriers.
N.I. Pavlov (ITOES) informed on developing the compact multi-spectral scanner for providing the digit images in visible and IR spectral ranges. Aircraft experiments with two-channel (0.4-0.7 and 8-12 m m) scanner demonstrated the perceptiveness of this instrument
Scientists of LPI RAS in collaboration with SPbSU have been developed the gas-correlation IR radiometer destined for determining the trace gas content in boundary atmospheric layer from measurements of solar radiation reflected from Earth surface. Results of modeling the CH4 content measurements in the 0-4 km layer from the 20 km height and optimizing the spectral characteristics were represented by Ya.A. Virolainen et al. (SPbSU). It was shown that measurements by the radiometer with optimal parameters could provide high accuracy of retrieving the CH4 content (5-10 % from background value).
Papers devoted to developing the miniature and automated ground-based means for determining the atmospheric gas content exited common interest. Such developments make possible to carry out the measurements in hard-accessible regions with small population. Specialists of MGO, SOI and IFMO developed and made the experimental model automatically operated spectrometer based on UV-polychromator. This compact instrument equipped by automated system of the guidance to different radiation sources gives a possibility to get the information on spectral distribution of direct, total and scattering radiation in the 290-430 nm range, O3, SO2 and NO2 content under any weather conditions (excluding the precipitation) and the spectral content of aerosol optical density in atmospheric total column.
The modernization of ground-based network for optical and microwave atmospheric sounding is very important. The plan of staged modernization of 5 stations for observing the stratospheric NO2, O3 and aerosol was proposed by LPI RAS, SOI and SSU (A.I. Igaev et al.). First experiments with modernized UV-spectrophotometer based on MDR-23 have been performed.
LPI RAS and SPbSTU reported the method of optical processing of the measurements by the radio-spectrometer of mm diapason that is used in the technique for ground-based ozone sounding. This processing is executed with the acoustic-optical spectrometer (AOS). Results of studying the characteristics of the radio-spectrometer with AOS and the first in Russia measurements of atmospheric ozone spectra were given. These data indicate that the use of the in complexes for atmospheric remote sending at mm wavelengths is fair effective.
In general, papers presented at Session 8 were interesting for scientists of different specialization. An essential fault is the absence of large space projects for obtaining the new home-made data on radiative characteristics of the atmosphere in regional and global scales. The same can be told about developments of instruments for aircraft and satellite experiments.
Degree of the influence of Russian scientists on the solving of problems in the field of atmospheric radiation is very different. There are considerable achievements in developing the theory of radiation transfer in Earth and planet atmospheres (in particular, for non–LTE conditions, for three-dimensional mediums), in monitoring the UV-irradiance of Earth surface, in obtaining the new data on atmospheric aerosol, in developing and applying the remote methods for measurements of atmospheric and surface parameters (Russian ground-based stations for controlling the ozonosphere and trace gases). Some efforts are undertaken for constructing the singular instrument models for remote sensing.
However there is an essential lag in the technique engineering and making:
Problem of reproducing the young community is very serious as well. The input of young scientists from Russia to the investigations in the field of atmospheric radiation is very small in comparing with that from other countries.