Atmospheric Physics and Climate Investigation Group (APCLING)

HOME RESEARCH ETA CCS CLIRAD PROGRAMS LINKS ABOUT ALL

Numerical modeling of regional atmospheric circulation:

Theoretical and diagnostic studies of global atmospheric processes:

Study of aerosols and clouds impact on Earth's radiation balance and climate:

Development of radiation transfer schemes for weather forecast and climate models. Analysis of performance of radiation schemes in atmospheric models:

Continuous dynamic assimilation.


In meteorological and oceanological studies the classical approach for finding the numerical solution of the regional model consists in formulating and solving a Cauchy-Dirichlet problem. The boundary conditions are obtained by linear interpolation of coarse-grid data provided by a global model. Errors in boundary conditions due to interpolation may cause large deviations from the correct regional solution. The methods developed to reduce these errors deal with continuous dynamic assimilation of known global data available inside the regional domain. One of the approaches of this assimilation procedure performs a nudging of large-scale components of regional model solution to large-scale global data components by introducing relaxation forcing terms into the regional model equations. As a result, the obtained solution is not a valid numerical solution to the original regional model. Another approach is the use a four-dimensional variational data assimilation procedure which is free from the above-mentioned shortcoming. We begin the the work on applications the achievements in a PDE-constrained optimization problem to finding the "regional" model solution under condition of continuous assimilation of available inner region data.
 ( Pisnitchenko F.I., I.A. Pisnichenko, J.M. Martinez, S.A .Santos.: Continuous dynamic assimilation of the inner region data in hydrodynamics modelling: optimization approach. Nonlinear Processes in Geophysics, v. 15, p. 815-829, 2008.
 J.M. Martínez, F.I. Pisnitchenko, I.A. Pisnitchenko, S. Santos. Optimization techniques for solving the Cauchy-Dirichlet problem. The sixth international conference on optimization, OPTIMIZATION2007, Porto, Portugal, July 22-25,2007.)




Adiabatic invariants and diagnostic investigations of atmospheric circulation.

Fundamental freedom existing in Ertel's general definition of potential vorticity (PV) is used to construct an essential invariant measure in (q,χ) space, where q is an "optimal" modified PV (OMPV) and χ is a monotonic increasing function of potential temperature, which enters q. This novel measure is preserved in idealized climate processes, when external diabatic heating and frictional forcing, being applied to zonally oriented infinitely thin (q,χ)tubes (formed at the expense of intersection between isoscalar surfaces q = constant and χ  = constant), annihilate each other. A reference stationary airmass distribution on (q,χ)values is introduced for both hemispheres, separately, which corresponds to a hypothetical atmospheric climate equilibrium state. This reference distribution, with no dependence on χ, is characterized by exponentially decaying function of the absolute value of q and has the same total amount of "PV substance" (atmospheric vorticity charge) as the actual atmospheric state. Comparison of the actual monthly mean airmass distribution on q (calculated on the basis of 1980-89 European Centre for Medium-Range Weather Forecasts data) with this reference stationary distribution by their informational entropy values enables one to quantify a degree of nonequilibrium of real atmospheric climate processes, with respect to the introduced invariant measure.
 (Kurgansky M.V., and I.A. Pisnichenko. Potential vorticity as an atmospheric climate variable. C. R. Acad. Sci. (DoKl.), v.357, n.1, p.104-107, 1997.
  Kurgansky M.V.,and I.A. Pisnichenko. Modified Ertel's potential vorticity as climate variable. Journ. of Atmos. Science, v.57, p.99-112, 2000.)

Using daily data of horizontal velocity, temperature and geopotential on seven levels for 2.5x2.5 gridpoints the daily PV and PT fields have been calculated. On the basis of these fields the daily air mass distribution of atmosphere on PV and PT values was calculated, also was made the calculation of informational entropy and the first momenta (vorticity charge - total amount of potential vorticity substance in the atmosphere, and PT of the whole atmosphere) of this distribution. The calculations have been carried out for the period 1980-1989 years. We used the ECMWF data. To investigate the interaction between hemispheres and various regions of the Earth the calculations was carried out for: a) the entire globe; b) the Northern Hemisphere and the Southern Hemisphere separately; c) the equator region, middle latitude region, polar region and territory of Brazil separately.
In addition to this the following calculations was conducted: a) Boltzman's entropy for equilibrium distribution of the mass of atmosphere on PV values; b) the three components of angular momenta; c) kinetic energy; d) available potential energy; e) free energy; f) the first fifteen ultra-long wave amplitudes in spherical function decomposition of the geopotential field.
In order to study the role of nonlinear interactions in the climate processes we made calculations using as daily data, so previously obtained monthly-means averaged data. The archive of some useful meteorological characteristics as daily so monthly-means is prepared and is available now in CPTEC. There are, for example, 3-dimensional monthly-means fields of horizontal velocity, geopotential, temperature, relative humidity. There are also potential vorticity fields as daily so monthly-means on 305 and 310 K isentropic surfaces. All these data are available for the period of 1980-1989 years. Statistical analysis of the time series of these meteorological characteristics revealed stable correlations between the peculiarities of their behavior and the various types of the atmospherical circulation.
It was made an attempt to apply PV analysis for verification of CPTEC General Circulation Model (Brazil). The previous results demonstrate advantages of such approach. The usage of adiabatic invariants and functionals from them as the comparing parameters gives more pronounce picture of difference between the forecast and analysis then we have in the case of commonly used meteorological fields.
 (Pisnichenko I.A., and M.V. Kurgansky. Adiabatic invariants and diagnostic studies of climate. Anais da Academia Brasileira de Ciencias, v.68, n.1.1, p. 261-277, 1996.
 Pisnichenko I.A., Kurgansky M.V. Application of the modified Ertel's potential vorticity to investigation of South Hemisphere circulation. XI Congresso Brasileiro de Meteorologia, 16-20 outubro,2000, Rio de Janeiro.
 Kurgansky M.V., Pisnichenko I.A. Application of the modified Ertel's potential vorticity to investigation of atmospheric climate variability. Sixth International conference on Southern Hemisphere meteorology and oceonography. 3-7 April, 2000, Santiago, Chile.)

Comparative study of OMPV and others meteorological parameters was made for various regions of South America: Brazil, South Brazil, North Brazil, Central and Southern Chile. Applying the OMPV to analisys of various climate regimes gave promising results. It was carried out diagnostic investigations of ENSO regimes with the aim to detect connections between ENSO phase and peculiarities of local circulation over South Brazil and North Brazil. The correlations between variations of intensity of precipitation over west cost South America in subtropical lattitudes and variations of large-scale potential vorticity was analysed. It was proposed some theoretical models explaining the climate variations and peculiarities of precipitation over Central and Southern Chile regions.
 (Pisnichenko I.A., Grimm A., Natori A., de Oliveira F. Relacoes entre os processos ENOS de grande escala e peculiaridades clima regional no Sul do Brasil. XI Congresso Brasileiro de Meteorologia, 16-20 outubro, 2000, Rio de Janeiro, Brazil.
 Zaratini P., Pisnichenko I.A., Grimm A. Relacoes entre os processos ENOS em grande escala e peculiaridades climaticos regionais no Norte do Brasil. XI Congresso Brasileiro de Meteorologia, 16-20 outubro, 2000, Rio de Janeiro, Brazil.
 Kurgansky M.V., Pisnichenko I.A. Potential vorticity representation of the atmospheric climate processes. VIII Congreso Argentino de Meteorologia y IX Congreso Latinoamericano e Ibirico de Meteorologia, 2001, Buenos Aires, Argentine.
 Pisnichenko I.A. Investigations of interannual variations of potential vorticity field and their functionals for some regions of South America. VIII Congreso Argentino de Meteorologia y IX Congreso Latinoamericano e Ibirico de Meteorologia, 2001, Buenos Aires, Argentine.)

Regional atmospheric models.

A sensitivity of regional mesoscale model ARPS to boundary conditions and to various schemes of physical parameterizations was studied. It was applied the old, well-known indexes and developed some new methods and programs for evaluating the model skill score. Necessary adjustment in ARPS mesomodel for using it as operational model for Parana state region in Brazil was made.
 (Dias N.L., Gobbi M.F., Pisnitcheno I.A., Dornelles V.J., Chemecki M. Projeto Mesopar: Implementacao e Operacionalizacao do Modelo de Mesoescala ARPS. Relatorio Tecnico N 001/2001, 2001.
 Gobbi M.F, Chamecki M, Pisnichenko I.A., Vissotto Junior D., Dias N.L. Implementacao de um modelo de mesoescala para a regiao Sul do Brasil. Congresso Brasileiro de Meteorologia,2002.)

A new version of Eta WS (workstation) forecast model destined for long term climate change simulation (Eta CCS) was designed. Numerous modifications and corrections have been made in the original code of the Eta WS forecast model. As a first step in the Eta CCS validation program, the model have been integrated over South America with a horizontal resolution of 40 km for the period 1960-1990. ETA CCS was forced at its lateral boundaries by the outputs of HadAM3P, which provides a simulation of modern climate with a resolution of about 150 km. The climate Eta CCS model was run on the supercomputer SX-6. The output fields (a geopotential, a temperature, a wind) of the Eta model and HadAM3P was compared and analyzed. For evaluating the similarities of the model outputs, a Fourier analysis of time series, the consistency index from linear regression coefficients, the time mean and space mean models' arithmetic difference and root mean square difference were used. The results of the study demonstrate that there are no significant differences in behavior and spatial arrangement of large-scale structures of the two models. In addition, the regional model characteristics do not have major positive or negative trends during the integration in relation to the global model. Our analysis shows that the descriptions of large-scale climate structures by these two models are consistent. This means that the Eta CCS model can be used for downscaling HadAM3P output fields. Technique proposed in this study can be used to evaluate the consistency of any regional model and its driving global model.
We make also downscaling experiment with the output of global model HadAM3P for scenarios A2 and B2 (2070-2100 period) over South America. These data are anlised now.
 (Pisnichenko, I.A., T.A. Tarasova, J.P.R. Fernandez, and J.Marengo. Validation of the Eta WS regional climate model driven by boundary conditions from the HADAM3H over South America. Proceedings of 8 ICSHMO, Foz do Iguacu, Brazil, April 24-28, 2006, INPE, p. 595-597.
 Pisnichenko, I.A., and T.A. Tarasova. The climate version of the Eta regional forecast model. 1. Evaluation of consistency between the Eta model and HadAM3P global model. http://arxiv.org/abs/0709.2110v2,. 2007.
 Marengo J., C.Nobre, D. Raigoza, C. D'Almeida, I. Pisnitchenko. Using Regional Climate Change Scenarios For Studies on Volnerability and Adaptation in Brazil and South America: Amazon, Sao Francisco, and Parana-La Plata River Basins. CEOP/IGWCO Joint Meeting, Unesco, Paris, France, 26 February 1 March 2006.)

Investigations of blockings

Research of blocking situations in the atmosphere using adiabatic invariants approach was made. Determination of a diagnostic relation between dissipation and heat inflow is one of the directions in this study. Investigated the role of orography in the interaction of Rossby waves with the zonal flow.
 (Agayan G.M., M.V. Kurganskiy, I.A. Pisnichenko. Analysis of blocking in the atmosphere using adiabatic invariants and FGGE data. Izvestiya, Atmospheric and Oceanic Physics,, v.22, No.11, 1986.
 Agayan G.M., M.V. Kurganskiy, I.A. Pisnichenko. Calculation of a field of heat influxes using the equation of potential vorticity transformation. Meteorologiya i Gidrologiya,, No.7, p.19-27, 1990.
 Pisnichenko I.A. A low-order model of the effect of orography on large-scale atmospheric flows. Izvestiya, Atmospheric and Oceanic Physics,, v.24, No.9, 1988.
 Kurganskiy M.V., I.A. Pisnichenko, and Yu.L. Chernous'ko. Laboratory and theoretical study of stationary Rossby waves above isolated barriers in an annulus. Izvestiya, Atmospheric and Oceanic Physics, ,v.23, No.7, 1987.)

Global atmospheric circulation and instability theory

Variations of non-axial components of angular momentum as a result of the interaction of Rossby waves with zonal flow at the presence of orography were investigated. Periods and amplitudes of such oscillations (manifesting in the position of the latitude of an observation station in reference frame bound with stars) are obtained. This model, connecting variations of angular momentum components of Earth with the exchange of angular momentum between atmosphere and rigid core of Earth at the expense of interaction of Rossby waves with orography, can become the basis for the construction more precise theory, ascertaining the correlation between the oscillations of angular velocity of Earth's rotation and the changes of latitude of observation station. It will give the possibility to use long astronomical series of measurings for diagnostic investigations of atmospheric circulation.
 (Pisnichenko I.A.On certain mechanism of an excitement of angular momentum equatorial components. X Congresso Brasileiro de Meteorologia, Brasilia, 25-30 outubro de 1998.)

The stability of zonal flow in a baroclinic atmosphere with respect to finite amplitude planetary-scale disturbances by applying Arnold's method was investigated. Specifically, we examine the sign of the second variation of a conserved functional for the case of a polytropic atmosphere (i.e. one with a linear lapse rate) and with a linear profile of zonal wind. Sufficient stability conditions for an infinite atmosphere (i.e. with a temperature lapse rate equal to zero) are satisfied only for an atmosphere in solid body rotation. For a polytropic atmosphere of finite extent (a lapse rate is not equal zero) the sufficient conditions of stability can be satisfied if a lid is placed below min(Zmax, polytropic atmospheric height). The dependence of height Zmax on values of the vertical gradient of the zonal wind and the zonal temperature distribution was calculated.
 (Pisnichenko I.A. Nonlinear instability of baroclinic atmosphere with reference to planetary scale disturbance. Nonlinear Processes in Geophysics, v.11, p. 363-370, 2004.)

Assessment of tropospheric aerosol impact on solar radiative fluxes and global climate using IAP climate model.

The climate model developed by Petukhov (1980) in the Institute of Atmospheric Physics (IAP), Soviet Academy of Sciences, Moscow, USSR, was used for the evaluation of tropospheric aerosols impact on global albedo and near surface air temperature (Manuylova et al. 1984). In this thermodynamical zonally averaged model, the main equation is the equation of heat balance and the temperature is the main variable. The main feedback relations and the dynamical processes are parameterized. We developed new solar radiation code (Tarasova, 1981; Tarasova and Feigelson, 1981; Tarasova and Feigelson, 1983) for this model and implemented it into the model. The runs of the IAP model were made with different aerosol loading of the troposphere. It was shown that tropospheric aerosols with global mean aerosol optical depth (AOD) of 0.125 and single scattering albedo (SSA) of 0.95 decrease global mean near surface air temperature by 3.4 K as compared with aerosol-free atmosphere. The aerosols with AOD=0.28 and SSA=0.95 decrease surface temperatures by 6.8 K, while aerosols with AOD=0.28 and SSA=0.8 decrease surface temperatures only by 2.6 K. Further decreasing of SSA associated with the increase of aerosol absorption leads to the increase of surface temperature. These results were among the first to demonstrate the importance of accurate measurement of optical parameters of tropospheric aerosols for accurate evaluation of aerosol impact on the Earth's climate.
 ( Tarasova T.A. and E.M Feigelson. On the aerosol effects in the radiative heat exchange, Izvestiya, Atmospheric and Oceanic Physics, (English translation), 17, (1), 18-26, 1981.
  Tarasova T.A. Relationship between the spectral and integral albedo of a cloudless sky, Izvestiya, Atmospheric and Oceanic Physics, (English translation), 17, (12), 1330-1333, 1981.
  Tarasova T.A. and E.M Feigelson. Troposphere aerosol influence on integral albedo of the cloudy atmosphere-underlying surface system, Izvestiya, Atmospheric and Oceanic Physics, (English translation), 19, (11), 1161-1166, 1983.
  Manuilova, N.I., V.K.Petukhov, T.A.Tarasova, and E.M.Feigelson. Assessment of radiation-climatic effects of natural and man-made aerosols, Izvestiya, Atmospheric and Oceanic Physics, (English translation), 20, No 11, 918-922, 1984.)

Methods for retrieving of aerosols and clouds optical parameters from radiation measurements on the ground.

The following methods were proposed for the derivation of aerosol and cloud optical parameters from the integral and broadband direct beam and diffuse solar radiation measurements at the Earth's surface:

AEROSOL OPTICAL DEPTH

1. The methods for retrieving of aerosol optical depth at the wavelength of 550 nm (AOD550) from integral (IR) (300 nm - 4000 nm) and visible (VIS) (380 nm - 710 nm) direct beam solar radiation incident at the surface in clear-sky conditions. The methods are based on the detailed calculations of molecular, aerosol, ozone, and water vapor extinction (Tarasova and Yarkho, 1991; Abakumova et al., 1992).

With the use of these methods, the values of AOD550 have been obtained from the long-term direct beam visible solar radiation measurements taken at Meteorological Observatory of Moscow State University (MO MSU) from 1971 to 1989 (Abakumova et al., 1992) and from the direct beam integral solar radiation measurements taken by IAP and MO MSU during the field experiment conducted from April to May, 1986 in Moscow region (Abakumova et al., 1989), during large biomass burning in Moscow Region in August 1972 (Sokolik et al., 1986), during the ship expeditions to Atlantic Ocean from February to October, 1987 (Abakumova et al., 1989), from June to August, 1979 (Krasnokutskaya et al., 1985) and from September to December, 1991 (Tarasova et al., 1992).
 ( Krasnokutskaya, L.D., I.I.Mokhov, and T.A.Tarasova. Determination of solar radiation flows in cloudless atmosphere of the equatorial Atlantic according to FGGE data, Soviet Meteorology and Hydrology, (English translation), No 1, 80-84, 1985.
  Sokolik, I.N., T.A.Tarasova, and E.M.Feigelson. Optical characteristics of smoke-filled atmosphere and the radiation heating, Soviet Meteorology and Hydrology,(English translation), No 11, 35-42, 1986.
 Abakumova, G.M., I.N.Plakhina, and T.A.Tarasova. Estimate of aerosol optical thickness of the atmosphere according to data of the land-based and ship actinometric measurements. Soviet Meteorology and Hydrology, (English translation), No 10, 36-44, 1989.
  Tarasova, T.A. and E.V.Yarkho. Determination of aerosol optical thickness using measurements of direct integral solar radiation. Soviet Meteorology and Hydrology, (English translation), No 12, 66-71, 1991.
 Abakumova, G.M., T.A. Tarasova, and E.V. Yarkho. Determination of aerosol optical thickness of the atmosphere from direct photosynthetically active radiation,Soviet Meteorology and Hydrology, (English translation), 10, 63-67, 1992.
  Tarasova, T.A., I.N.Plakhina, and I.A.Repina. Comparison of measured and calculated global radiation at the ocean surface and calculation of extended clouds optical thickness. In: Preliminary results of the experiment in the Atlantic ocean according to the program ASTEX-91. Institute of Atmospheric Physics, Russian Academy of sciences, Moscow, p.34-40, Preprint No 4, (in Russian), 1992.)

AEROSOL SINGLE SCATTERING ALBEDO

2. The method for derivation of aerosol single scattering albedo (SSA) averaged over solar spectrum from simultaneous measurements of solar direct beam and diffuse broad band solar radiation incident at the Earth's surface in clear-sky conditions (Tarasova et al., 1992).

With the use of this method, the values of SSA were retrieved from the long-term radiation measurements taken at MO MSU during summer from 1955 to 1991, during dust aerosol radiation field experiment in Dushanbe region (Central Asia, Former Soviet Union) in September 1988 (Tarasova et al., 1992) and during large biomass burning in Moscow Region in August 1972 (Sokolik et al., 1986).
 ( Sokolik, I.N., T.A.Tarasova, and E.M.Feigelson. Optical characteristics of smoke-filled atmosphere and the radiation heating, Soviet Meteorology and Hydrology,(English translation), No 11, 35-42, 1986.
  Tarasova, T.A., G.M.Abakumova, and I.N.Plakhina. Determination of the absorbing properties by aerosol haze from measurements of direct and total integral solar radiation under a clear sky. Izvestiya, Atmospheric and Oceanic Physics,(English translation), 28, No 4, 288-294, 1992.
 Tarasova T.A.,T. F.Eck, B.N. Holben, A.Setzer. On derivation of the smoke single-scattering albedo using radiative transfer calculations and sun photometer and broad band irradiance measurements made in Cuiaba on 27 and 28 August 1995. 4 p. In: Proceedings of SCAR-B meeting on 3-8 November 1996, Fortaleza, Brazil.)

CLOUD OPTICAL DEPTH

3. The method for the derivation of cloud optical depth (COD) from the ratio of solar radiation incident fluxes measured under cloudy and clear-sky conditions (Tarasova and Chubarova, 1994). Simple formulas were obtained as a result of the least square fitting to the detailed radiation calculations of this ratio. The method is valid for homogeneous middle and low extended water droplet cloudiness located over the ocean or snow-free surfaces.

The values of COD of extended stratocumulus clouds were retrieved from the long-term measurements of integral solar incident radiation, carried out at MO MSU from 1980 to 1990 (Izakova et al., 1994), from radiation measurements taken during cloud-radiation field experiment in Moscow region in October 1992 (Tarasova and Chubarova, 1994) and from radiation measurements taken during the ship expedition to Atlantic Ocean from September to December, 1991 (Tarasova et al., 1992).
 (Tarasova, T.A., I.N.Plakhina, and I.A.Repina. Comparison of measured and calculated global radiation at the ocean surface and calculation of extended clouds optical thickness. In: Preliminary results of the experiment in the Atlantic ocean according to the program ASTEX-91. Institute of Atmospheric Physics, Russian Academy of sciences, Moscow, p.34-40, Preprint No 4, (in Russian), 1992.
 Tarasova, T.A. and N.Ye.Chubarova. On the calculation of optical thickness of extended low and middle clouds using measurements of solar radiation in three solar spectrum ranges on the Earth's surface. Izvestiya, Atmospheric and Oceanic Physics, (English translation),30, No 2, 253-257, 1994.
 Izakova O.M., T.A.Tarasova, N.Ye. Chubarova, O.A.Shilovtseva. Transmittance of global radiation in different regions of spectrum by extended stratocumulus clouds and their optical thicknesses based on long-term ground measurements, Izvestiya, Atmospheric and Oceanic Physics,(English translation), 30, No 3, 378-382, 1994.
 Tarasova T.A., and Chubarova N.Ye. Evaluation of cloud optical thickness using ground based radiation measurements in different ranges of solar spectrum. In: Eighth Conference on Atmospheric Radiation, Nashville, Tennessee, USA, Proceedings, American Meteorological Society, 202-204, 1994.
 Chubarova, N.Ye., O.M.Izakova, O.A.Shilovtseva, and T.A.Tarasova. Transmittance of global radiation in different regions of spectrum by extended strato-cumulus clouds and their optical thickness based on long-term ground measurements. In: Eighth Conference on Atmospheric Radiation, Nashville, Tennessee, USA, Proceedings, American Meteorological Society, 564-566, 1994.)

OPTICAL PARAMETERS OF CIRRUS CLOUDS

4. The methods for the derivation of cirrus cloud optical parameters from radiation measurements at the Earth's surface. Evaluation of the cirrus clouds' impact on solar radiation fluxes and radiative balance at the top of the atmosphere and at the Earth's surface.
 ( Pavlova L.N., Petrushin A.G., and Tarasova T.A. Radiation features of ice clouds, Izvestiya, Atmospheric and Oceanic Physics, (English translation), 17, (4), 434-439, 1981.
 Anikin, P.P., A.G.Petrushin, and T.A.Tarasova. Optical characteristics of cirrus clouds. In: Feigelson E.M., ed. Radiative properties of cirrus clouds, Moscow, Nauka, 224 p. (in Russian), 1989.
 Anikin P.P., Feigelson E.M., Gorchakova I.A., Tarasova T.A. Radiative properties of cirrus clouds. Atmosfera, 4, (4), 205-233, 1991.
 Tarasova, T.A. Cirrus optical properties determination from actinometric observations. Izvestiya, Atmospheric and Oceanic Physics,(English translation), 27, No 9, 690-696, 1991.
  Tarasova, T.A. Calculation of solar radiation and comparison with measurements. In: E.M. Feigelson, S.Cox eds. Cirrus cloud properties deduced from Zvenigorod experiments and theoretical investigation 1986-1990. Atmos. Sci. Paper, No. 516, Colorado State Univ., Depart. of Atmos. Sciences, Fort Collins, CO, 199 p., 1992.
 Tarasova T.A. Evaluation of aerosol and cirrus cloud single scattering albedo using actinometric measurements. In: Keevalik and Karner eds., IRS'92: Current Problems in Atmospheric Radiation, Proceedings, A.DEEPAK Publishing, 90-92, 1992.)

Study of aerosols and clouds impact on top and surface radiation balance. Development of broadband solar radiation codes for radiative transfer calculations.

The impact of aerosols and clouds on solar radiative fluxes has been estimated using broadband solar radiation schemes. The accuracy of these schemes were evaluated from the comparison with the exact line-by-line methods of radiative transfer calculations.
 ( Pavlova L.N., Petrushin A.G., and Tarasova T.A. Radiation features of ice clouds, Izvestiya, Atmospheric and Oceanic Physics, (English translation), 17, (4), 434-439, 1981.
  Tarasova, T.A., and E.A.Ustinov. Radiation fluxes in the cloud-aerosol atmosphere - underlying surface. Izvestiya, Atmospheric and Oceanic Physics, (English translation), 21, No 4, 331-334, 1985.
 Gorchakova, I.A., T.A.Tarasova, E.A.Ustinov, and E.M.Feigelson. Radiative heating of the atmospheric surface layer. Izvestiya - Atmospheric and Oceanic Physics, (English translation), 24, No 5, 387-390, 1988.
 Petrushin, A.G. and T.A.Tarasova. Effect of cirrus clouds on solar radiation fluxes. Izvestiya, Atmospheric and Oceanic Physics, (English translation), 25, No 5, 368-373, 1989.
 Gorchakova, I.A. and T.A.Tarasova. The influence of cirrus clouds on the radiative balance of the atmosphere top boundary, Earth surface and heating of the atmosphere column. In: Feigelson E.M., ed. Radiative properties of cirrus clouds, Moscow, Nauka, 224 p. (in Russian), 1989.
 Veltishev, N.N., T.A.Tarasova and V.A.Frolkis. Practical methods of the calculation of the solar radiation absorption by water vapor in different radiative schemes. Institute of Atmospheric Physics, USSR Academy of Sciences, Moscow, 27 p., Preprint No. 11 (in Russian), 1990.
 Tarasova T.A. Different versions of the Delta-Eddington approximation and the simultaneous calculation of the water vapor absorption in radiation codes for models.4 p. In: Proceedings of the International Radiation Symposium, August 1996, Alaska, Fairbanks, USA.
 Gorchakova, I.A., I.I. Mokhov, T.A. Tarasova, B.A. Fomin. Effect of clouds on radiative transfer in the atmosphere from the data of the 1999 winter Zvenigorod Experiment, Izvestiya, Atmospheric and Oceanic Physics, 37, Suppl. 1, S134-S141, 2001.
 Tarasova, T.A., I.A. Gorchakova, M.A. Sviridenkov, P.P. Anikin, and E.V. Romashova. Estimation of the Radiative Forcing of Smoke Aerosol from Radiation Measurements at the Zvenigorod Scientific Station in the Summer of 2002, Izvestiya, Atmospheric and Oceanic Physics, (English translation) Vol.40, No.4, 454-463, 2004.
 Gorchakova,I.A, T.A. Tarasova, M.A. Sviridenkov, P.P. Anikin, and E.V. Romashova. Modelling of radiative forcing of background aerosols with the use of the data of radiation measurement at the Zvenigorod science station IAP RAS (spring-summer 2004, summer 2005). Accepted to Izvestiya, Atmospheric and Oceanic Physics, 2008.)

REVIEW OF METHODS OF RADIATIVE TRANSFER CALCULATIONS AND RETRIEVING OF CLOUD AND AEROSOL OPTICAL PARAMETERS DEVELOPED AT IAP SINCE 1981 TO 1995.

 (Tarasova T.A. Optical and radiative characteristics of cloudy and aerosol atmosphere, An. Acad, Bras. Ci., 68 (1), 171-180, 1996.)

Analysis of solar irradiance measurements made at observational sites in Brazil's Amazonia in smoke aerosol conditions.

ANALYSIS OF SOLAR IRRADIANCE MEASUREMENTS MADE IN AUGUST AND SEPTEMBER 1995 AT OBSERVATIONAL SITES IN RONDONIA REGION AND MATO GROSSO DURING SCAR-B FIELD EXPERIMENT.

The measurements of both aerosol optical depth and solar irradiance in August and September 1995 at observational sites in the Rondonia region and Mato Grosso during SCAR-B field experiment provided data for the study of smoke aerosol impact on the solar radiative flux incident at the surface (Tarasova et al., 1999). For the analysis of the observational data, the broadband radiative transfer code was developed and tested with the use of the observational data (Tarasova and Eck, 2001). The calculation results have shown that solar radiation attenuation by smoke aerosols cause a negative trend in the daily average clear-sky solar irradiance at the surface from the beginning of August to mid-September. The solar radiation absorption in the atmospheric column by smoke aerosols is comparable with absorption by water vapor, while the cloudiness effect is much smaller.

The data of the daily minimum and maximum near surface air temperature obtained at the observational site Reserva Jaru in Brazil's Amazonia in August-September 1995 were analyzed in conjunction with the data of the incident solar irradiance and net thermal irradiance at the surface (Tarasova and Nobre, 2001). The calculations with the broadband code have shown that the absence of the trend in the daily maximum temperature from the beginning of August to mid-September is explained by the constant solar radiation absorption in both aerosol layer of 2 km and surface layer. The positive trend in the daily minimum temperature can be explained by increasing in the night of the downward longwave radiative flux from the heated aerosol layer to the surface.
 (Tarasova T.A., C.A. Nobre, B.N. Holben, T.F. Eck, A. Setzer. Assessment of smoke aerosol impact on surface solar irradiance measured in the Rondonia region of Brazil during Smoke, Clouds, and Radiation - Brazil, J. Geophys. Res., 104, 19,161-19,170, 1999.
 Tarasova, T.A., and T.F. Eck. Improvements in the broadband radiative transfer code aimed to achieve better agreement between modeled and measured solar irradiances on the ground, in IRS'2000: Current Problems in Atmospheric Radiation, W.L Smith and Yu.M. Timofeyev (Eds.), A. Deepack Publishing, Hampton, Virginia, pp. 1073-1077, 2001.
 Tarasova, T.A., and C.A. Nobre. On the temperature aerosol effect measured in Brazil's Amazonia during the dry season in smoke aerosol conditions, in IRS'2000: Current Problems in Atmospheric Radiation, W. L. Smith and Yu. M. Timofeyev (Eds.), A. Deepack Publishing, Hampton, Virginia, pp. 737-741, 2001.)

Study of water vapor, aerosol, and cloudiness impact on incident solar irradiance continuously measured in Brazil's Amazonia at six observational sites from 1992 to 1995.

The effect of water vapor, aerosol, and cloudiness on the incident surface solar irradiance continuously measured in Brazil's Amazonia at six observational sites from 1992 to 1995 were examined by means of a clear-sky broadband radiative transfer model (Tarasova et a., 2000). The aerosol optical depth and precipitable water, both retrieved from Sun photometer measurements, serve as inputs to the model. The analysis of the computed and measured irradiances has shown that during the wet season the gaseous and cloudiness effects on the solar radiation attenuation in the atmosphere are comparable in magnitude, while the aerosol influence is much smaller. The aerosol effect increases and cloudiness effect decreases in the second half of the dry season. Both cloudiness and aerosol effects have strong seasonal variations, while the gaseous effect changes slightly during the year.
 (Tarasova T.A., C.A. Nobre, T.F. Eck, B.N. Holben. Modeling of gaseous, aerosol, and cloudiness effects on surface solar irradiance measured in Brazil's Amazonia 1992-1995, J. Geophys. Res., 105, 26,961-26,971, 2000.)

Modifications made in the NASA GSFC CLIRAD-SW solar radiation code for models.

The following modifications have been made in the NASA GSFC CLIRAD-SW shortwave radiation code for models (Chou and Suarez, 1999): The CLIRAD-SW-M modified version (Tarasova and Fomin, 2000) takes into account the continuum absorption by water vapor. The CLIRAD(FC05)-SW modified version (Tarasova and Fomin, 2007) uses the new parameterizations of gaseous absorption of Fomin and Correa (2005). The new parameterizations allow to halve the number of spectral intervals in the code and hence to halve its computational time without loosing the code accuracy. The error of the code was determined as the difference between the flux of heating rate values calculated with the code and with the line-by-line model. The errors in the top-of-the-atmosphere and surface fluxes are less than 1-2 W/m2 in clear-sky atmosphere, and are less than 7 W/m2 in cloudy atmosphere. The errors of heating rate calculations are about 20% in cloud layers (Tarasova and Fomin, 2008) and they are less than 5-10% in cloud-free atmosphere.
 (Tarasova T.A. and B.A. Fomin. Solar radiation absorption due to water vapor: Advanced broadband parameterizations, J. Appl. Met., 39, 1947-1951, 2000.
 Tarasova, T.A., and B.A. Fomin. The use of new parameterization for gaseous absorption in the CLIRAD-SW solar radiation code for models. J. of Atm. and Oceanic Technol., v. 24, No. 6, 2007, 1157-1162.
 T.A. Tarasova, and B.A. Fomin. Analysis of errors in the heating rate calculations in cloud layers with broadband shortwave radiation codes. International Radiation Symposium IRS2008, Foz de Iguacu, Brazil, August, 2008.)

Comparison of incident solar radiative fluxes simulated by CPTEC-COLA GCM over South America with satellite-derived data.

The incident solar radiative fluxes, simulated by the CPTEC-COLA atmospheric general circulation model over South America for the period 1986-1988, were compared with the satellite-derived surface fluxes provided by the Surface Radiation Budget (SRB) datasets. The comparison has shown that the model systematically overestimates both all-sky and clear-sky SRB fluxes while representing well their latitudinal variations. The results of testing of the model shortwave radiation code in a stand alone mode demonstrated that the code underestimates solar radiation absorption in the clear-sky atmosphere due to the trace gases and aerosols. The implementation in the model of modern shortwave radiation codes was proposed.
 (Tarasova T.A., and I.F.A. Cavalcanti. Monthly mean solar radiative fluxes and cloud forcing over South America in the period of 1986-1988: GCM results and satellite-derived data, J. Appl. Met., 41, 863-871, 2002.)

Implementation of new solar and thermal radiation schemes into CPTEC-COLA GCM and Eta regional climate model (ETA CCS).

The modern sophisticated solar and thermal radiation schemes have been implemented into the CPTEC Global model and Eta regional climate model (Eta CCS). Both modern and original schemes of the models were compared off line with the exact line-by-line method. The results of the comparison have shown that the modern schemes have much higher accuracy in fluxes' calculations than the original schemes.

The models with the new and original schemes were integrated for the periods from a few months to 10 years. The results of models' integrations have shown that a model with new radiation schemes simulates radiative fluxes at the surface in better agreement with the observed fluxes than a model with its original radiation schemes. The precipitation and near surface air temperature fields were not always improved. Further improvement of a model performance can be achieved by adjustment of other physical parameterization in a model in conjunction with its radiation schemes.
 (Tarasova, T.A., J.P.R. Fernandez, I.A. Pisnichenko, J.A. Marengo, J.C. Ceballos, M.J. Bottino. Impact of new solar radiation parameterization in the Eta model on the simulation of summer climate over South America, J. Appl. Meteorol. Climatol., v.45, N2, 318-333, 2006.
 Tarasova, T.A.H.M.J. Barbosa, S.N. Figueroa. Incorporation of new solar radiation scheme into CPTEC GCM. Sao Jose dos Campos: INPE/CPTEC, 44 p., 2006. (INPE-14052-NTE/371)
 Barbosa H.M.J., T.A. Tarasova, I.F.A. Cavalcanti. Impacts of a new solar radiation parameterization on the CPTEC AGCM climate features. J. Appl. Meteorol. Climatol., 47, No 5, 1377-1392, 2008.
 Pisnichenko, I.A., and T.A. Tarasova. The climate version of the Eta regional forecast model. 1. Evaluation of consistency between the Eta model and HadAM3P global model http://arxiv.org/abs/0709.2110v2, 2007.
 Tarasova T.A., and I.A. Pisnichenko. Performance of various radiation parameterization schemes in the climate version of the Eta model. International Radiation Symposium IRS2008, Foz de Iguacu, Brazil, August, 2008.)