Publications by Viivi Russak

Russak, V., 2011. Atmosfääri vastukiirgus Eestis. Publicationes Instituti Geographici Universitatis Tartuensis, 109, 141-148.

Ohvril H., Neiman L., Okulov O., Russak V., Uustare M., Kallis A., Terez E., Terez G., Gushchin G., Abakumova G., Gorbarenko E.: Updated multi-annual time series of column transparency, impact of wildfires. In: Proceedings of the International Symposium: Atmospheric Radiation and Dynamics (ISARD-2011), St. Petersburg-Petrodvorets, 21-24 June 2011, ST. Petersburg State University, Russia, 2011, 17-18.

2009

Ohvril H., Teral H., Neiman L., Kannel M., Uustare M., Tee M., Russak V., Okulov O., Jõeveer A., Kallis A., Ohvril T., Terez E.I., Terez G.A., Gushchin G.K., Abakumova G.M., Gorbarenko E.V., Tsvetkov A.V., Laulainen N.: Global dimming and brightening versus atmospheric column transparency, Europe, 1906-2007. J. Geophys. Res., 114, D00D12, doi:10.1029/2008JD010644, 1-17, 2009.

Russak V.: Changes in solar radiation and their influence on temperature trend in Estonia (1955-2007). J. Geophys. Res., 114, D00D01, doi: 10.1029/2008JD010613, 1-6, 2009.

2008

Raino Heino, Heikki Tuomenvirta, Valery S. Vuglinsky, Bo G. Gustaffson, Hans Alexandersson, Lars Bärring, Agrita Briede, John Cappelen, Delian Chen, Malgorzata Falarz, Eirik J. Førland, Jari Haapala, Jaak Jaagus, Lev Kitaev, Are Kont, Esko Kuusisto, Göran Lindström, H.E. Markus Meier, Miroslaw Miætus, Andres Moberg, Kai Myrberg, Tadeusz Niedêwiedê, Øyvind Nordli, Andres Omstedt, Kaarel Orviku, Zbigniew Pruszak, Egidijus Rimkus, Viivi Russak, Corinna Schrum, Ülo Suursaar, Timo Vihma, Ralf Weisse, Joanna Wibig. 2008. Past and Current Climate Change. In: Assessment of Climate Change for the Baltic Sea Basin, Eds: H.-J. Bolle, M. Menenti, I. Rasool, Springer-Verlag Berlin Heidelberg, ISBN:978-3-540-72785-9, 35-131.

Hans-Jörg Isemer, Viivi Russak, Heikki Tuomenvirta. 2008. Atmosphere. In: Assessment of Climate Change for the Baltic Sea Basin, Eds: H.-J. Bolle, M. Menenti, I. Rasool, Springer-Verlag Berlin Heidelberg, ISBN:978-3-540-72785-9, 386-398.

M. Kaasik, T. Ploompuu, R. Ots, E. Meier, H. Ohvril, O. Okulov, H. Teral, L. Neiman, V. Russak, A. Kallis, P. Post. 2008. Growth Acceleration of Pinus Sylvestris in Bog Stands due to Intensified Nutrient Influx from the Atmosphere. Oil Shale, Estonian Academy Publisher, ISSN 0208-189x, Vol. 25, No 1, 75-93.

Teolan Tomson, Viivi Russak and Ain Kallis. 2008. Dynamic Behavior of Solar Radiation. In: Recent Advances in Modeling Solar Radiation on Earth Surface, Ed. V. Badescu, Publishing House: Springer Verlag, ISBN 978-3-540-77454-9, 257-282.

M. Kannel, H. Ohvril, H. Teral, V. Russak, and A. Kallis. 2007. A simple parameterization of columnar aerosol optical thickness. Proc. Estonian Acad. Sci. Biol. Ecol., 56, 1, 57-68.

V. Russak, A. Kallis, A. Jõeveer, H. Ohvril, and H. Teral. 2007. Changes in spectral aerosol optical thickness in Estonia (1951-2004). Proc. Estonian Acad. Sci. Biol. Ecol., 56, 1, 69-76.

V. Russak, H. Ohvril, H. Teral. 2007. Multi-annual changes in columnar aerosol optical thickness in Estonia. In: CD-ROM: EGU General Assembly 2007. Geophysical Research Abstracts, Volume 9, 2007. ISSN: 1029-7006.

V. Russak. 2006. Changes in solar radiation in Estonia during the last half-century. In: CD-ROM:EMS Annual Meeting. Sixth European Conference on Applied Climatology (ECAC2006). Abstracts, Vol. 3, ISSN 1812-7053.

H. Ohvril, L. Neiman, H. Teral, M. Tee, V. Russak, O. Okulov, A. Kallis, G. Abakumova, E. Terez, G. Guschchin, G. Terez, F.J. Olmo, L. Alados-Arboledas, and N. Laulainen. 2006. Multi-annual variability of atmospheric transparency in some European locations. In: Conference on Visibility, Aerosols, and Atmospheric Optics, Vienna, September 3 to 6, 2006. Abstracts, 1 p.

A. Kallis, V. Russak, H. Ohvril. 2005. 100 years of solar radiation measurements in Estonia. In: Report of the Eighth Session of the Baseline Surface Radiation Network (BSRN) Workshop and Scientific Review (Exeter, UK, 26-30 July 2004). WCRP Informal Report No. 4/2005, C-1 - C-4.

A. Kallis, V. Russak. 2005. Hundred years from the beginning of solar radiation measurements in Estonia. In: Carl Kalk 200. Symposium on Historical Climatology. Publicationes Instituti Geographici Universitatis Tartuensis,Ed. J: Jaagus, 97,74-81.

M. Wild, H. Gilgen, A. Roesch, A. Ohmura, Ch.N. Long, E.G. Dutton, B. Forgan, A. Kallis, V. Russak, A. Tsvetkov. 2005. From dimming to brightening: decadal changes in solar radiation at Earth's surface. Science, Vol 308, Issue 5723, 847-850.

Tomson, T., Mellikov, E., Russak, V., Kallis, A. 2005. Variability of Solar Irradiance. Technical Sciences, University of Warmia and Mazury in Olsztyn, 8, 253--265, ISSN: 1505-4675.

H. Ohvril, H. Teral, M. Tee, V. Russak, O. Okulov, A. Kallis, G. Abakumova, E. Terez, G. Gushchin, G. Terez, F.J. Olmo, L. Alados-Arboledas and N. Laulainen. 2005. Multi-annual variability of atmospheric transparency in Estonia. In: Solaris 2005, 2nd Joint Conference. Proceedings, Athens, 42-46.

H. Ohvril, H. Teral, V. Russak, A. Kallis and N. Laulainen. 2005. Spectral aerosol optical depth derived from broadband direct solar irradiance, summer 2002, Estonia. In: Solaris 2005, 2nd Joint Conference. Proceedings, Athens, 48-50.

H. Teral, H. Ohvril, O. Okulov, V. Russak, A. Reinart, N. Laulainen. 2004. Spectral aerosol optical thickness from solar broadband direct irradiance - summer 2002, Tõravere, Estonia. In: Abstracts of the European Aerosol Conference 2004 (6-10 September 2004, Budapest, Hungary), J. Aerosol Science, pp 547-548.

V. Russak, H. Teral, H. Ohvril. 2004. Trends in atmospheric aerosol loading in Estonia during the period 1951-2003. In: CD - EMS Annual Meeting, Abstracts (Nice, France, 26-30 September 2004).

H. Teral, H. Ohvril, O. Okulov, V. Russak, A. Reinart. 2004. Calculation of atmospheric aerosol optical thickness from broadband direct solar radiation. In: Publ. Inst. Geographici Universitatis Tartuensis, 95, 31-44. (in Estonian).

V. Russak, A. Kallis. 2003. Handbook of Estonian Solar Radiation Climate. Tallinn, 384 (in Estonian).

V. Russak, I. Niklus. 2003. Beam-diffuse broadband irradiance ratio as a characteristic of atmospheric transparency. In: Publicationes Instituti Geographici Universitatis Tartuensis, 93, 288-294 (in Estonian).

E. Mellikov, T. Tomson, A. Kallis, V. Russak. 2003. Steady-state variability of solar irradiance. In: Abstract Book ISES 2003, ISES Solar World Congress 2003, June 14-19, Göteborg, Sweden, 247.

E. Mellikov, T. Tomson, A. Kallis, V. Russak. 2003. Steady-state Variability of Solar Irradiance. CD-ROM, Section P6, No 36, ISES, 6 pages.

V. Russak. 2002. Changes in atmospheric transparency in Estonia. In: Global Atmospheric Watch (GAW) Workshop, May 27-30, 2002, Riga, Latvia, Abstracts, 34-36.

V. Russak. 2002. Changes in net long-wave radiation in Estonia. In: Fourth European Conference on Applied Climatology (ECAC 2002), November 12-15, 2002, Brussels, Belgium. Abstracts.

V. Russak. 2001. Winter warming in Estonia resulting from changes in atmospheric circulation. In: Climate Change and Variability in Northern Europe, June 6-8th, 2001, Turku/Abo, Finland, Abstracts, 94.

S. Keevallik, V. Russak. 2001. Changes in the amount of low clouds in Estonia (1955-1995). International Journal of Climatology, 21, 389-397.

O. Okulov, H. Ohvril, H. Teral, M. Tee, V. Russak, G. Abakumova. 2001. In: Current Problems in Atmospheric Radiation, IRS 2000, A. Deepak Publ., Hampton, Virginia, USA, 725-728.

S. Keevallik, K. Loitjärv, R. Rajasalu, V. Russak. 2001. Meteorological regime of Lake Peipsi. In: Lake Peipsi, Meteorology, Hydrology, Hydrochemistry. Inst. of Zoology and Botany at the Estonian Agricultural University, Sulemees Publ., 18-37.

V. Russak. 2000. The impact of atmospheric circulation on atmospheric transmittance in Estonia. In: 3rd European Conference on Applied Climatology, 16-22 October 2000, Pisa, Italy, CNR-IATA, F.M.A., Abstracts, 178.

V. Russak. 1999. Changes in time series of some climate elements in Estonia in early spring. Publicationes Instituti Geographici Universitatis Tartuensis, 85, 52-60 (in Estonian).

S. Keevallik, V. Russak.1998. Trends in Estonian cloud cover (1955-1995). In: Second Study Conference on Baltex, Conference Proceedings. Ed. E. Raschke and H.-J. Isemer, 104-105.

V. Russak. 1998. Changes in Radiation Regime. In: Country Case Study on Climate Change Impacts and Assessments in the Republic of Estonia. Ministry of Environment, Republic of Estonia, and Stockholm Environment Institute Tallinn Centre, Tallinn, 25-27.

V. Russak. 1998. Seasonal peculiarities of long-term changes in radiation regime in Estonia. In: Climate Change Studies in Estonia. Ministry of Environment, Republic of Estonia, and Stockholm Environment Institute Tallinn Centre, Tallinn, 13-20.

V. Russak. 1998. Influence of increased cloudiness on air temperature in Estonia. Österreichische Beiträge zu Meteorologie und Geophysik, Nr 19, 101-107.

V. Russak, A. Jõeveer, A. Kallis. 1997. Atmospheric transmittance and its long-term changes in Estonia. Meteorol. Zeitschrift, N.F.6, 137-141.

V. Russak. 1997. Trends in radiation regime observed in Estonia. In: Annales Geophysicae. Part II, Supplement II to vol. 15. Abstracts of EGS XXIII General Assembly, Vienna, April 21-25, 1997, C494.

G. M. Abakumova, E. M. Feigelson, V. Russak, V. V. Stadnik. 1996. Evaluation of long-term changes in radiation, cloudiness, and surface temperature on the territory of the former Soviet Union. Journal of Climate, vol. 9, No. 6, 1319-1327.

V. Russak. 1996. Atmospheric aerosol variability in Estonia calculated from solar radiation measurements. Tellus, 48A, 786-791.

H. Ohvril, V. Russak, H. Teral, M. Arak, K. Kaasik, K. Teral, F.J.O. Reyes, L.A. Arboledas.1996. Atmosfääri läbipaistvus Eestis viimase 60 aasta jooksul. Kogumikus: Eesti Teadlaste Kongress 11.-15. augustini 1996.a. Tallinnas. Teaduste Akadeemia Kirjastus, Tallinn, 140.

V. Russak. 1996. Changes in atmospheric aerosol in Estonia. In: Climate Variability and Climate Change Vulnerability and Adaptation. Proc. of the Regional Workshop, Prague, Sept. 11-15, 1995. Czech Academy of Sciences, 263-266.

V. Russak. 1996. Radiation climate change in Estonia. In: Meteorological Processes in the Boundary Layer of the Atmosphere. International Conference, Oct. 7-11, 1996, Stara Lesna, Slovakia. Proceedings. Slovak Academy of Sciences, 226-231.

H. M. ten Brink, H. Grassl, I. Schult, G. Marrachi, M. Bindi, J. A. Scott, R. Dlugi, V. Russak. 1995. Reduction of solar radiation by manmade aerosol in Europe. Netherlands Energy Research Foundation ECN, 54 pp.

V. Russak. 1995. On wind regime changes at Tõravere (Estonia). In: Meteorology in Estonia in Johannes Letzmann's times and today. Estonian Academy Publishers, Tallinn, 149-155.

V. Russak. 1995. Enhanced greenhouse effect in Estonia. In: Regional Climate Change in Central and East Europe. Proceedings of the Workshop in Budapest, Nov. 28-30 1994. Magyar Tudomanyos Akademia, 82-85.

V. Russak. 1995. Long-term changes in radiation regime in Estonia. In: Climate change and Waters in the Boreal Zone. Abstracts of the SILMU Symposium, Nov. 21-21, 1995 in Kuhmo, Finland. Publications of the Academy of Finland 7/95, 34.

V. Russak. 1995. Atmospheric aerosol variability in Estonia. In: Proceedings of the First Study Conference on BALTEX, Visby, Aug. 28 - Sept. 1, 1995. SHMI, Norrköping, Sweden, 151.

V. Russak. 1994. Is the radiation climate in the Baltic Sea region changing? Ambio, XXIII, 2, 160-163.

V. Russak. 1994. Changes in the radiation regime in Estonia. Fizika atmosfery i okeana, v.30, 3, 397-401 (in Russian).

V. Russak. 1994. Enhancing of greenhouse effect at Tõravere. In: Annual of the Estonian Physical Society 1993, Tartu, 137-145 (in Estonian).

V. Russak. 1993. Changes in net radiation during last decades in Estonia. In: IRS'92: Current problems in atmospheric radiation, A. Deepak Publishing, 264-266.

V. Russak. 1993. Changes in radiation budget in Estonia. In: Energy, Environment and Natural Resources Management in the Baltic Sea Region - 4th International Conference on System Analysis, Tallinn, Estonia, May 18-21,1993. 331-335.

V. Russak. 1992. Solar radiation at Tõravere. Ph. D. Thesis in Geogr., Tartu University, Tartu, 30 pp (in Russian).

A.Kallis and V. Russak. 1992. The influence of different cloud forms on diffuse radiation. In: Abstracts of International Radiation Symposium IRS'92, Tallinn, Estonia, Aug 3-8, 1992, 36.

V. Russak. 1992. Changes in net radiation during last decades in Estonia. In: Abstracts of International Radiation Symposium IRS'92, Tallinn, Estonia, Aug 3-8, 1992, 145.

J. Ross, V. Russak and R.Kivi. 1992. Is the climate of Estonia changing? In: Abstracts of the 4th International Conference on Statistical Methods for the Enviromental Sciences, Helsinki, 1992, 122-123.

V. Russak. 1991. Changes in solar radiation, cloudiness and atmospheric transparency during recent decades. In: IGARSS'91. Remote Sensing: Global Monitoring for Earth Management. Vol.I, 53-55.

J. Ross ja V. Russak. 1991. Eesti kiirguskliima muutumine aastail 1950-1990 ja selle võimalikud Ökoloogilised tagajärjed. Kogumikus: Kaasaegse ökoloogia probleemid. Tartu, 151-152.

V. Russak. 1990. Trends of solar radiation, cloudiness and atmospheric transparency during recent decades in Estonia. Tellus, v.42B, 2, 206-210.

V. K. Russak. 1990. The influence of the upper-level cloudiness on the solar radiation. In: Frequency and radiative properties of the upper-level clouds. Sov. Geophys. Comm., USSR Acad. Sci., Moscow, 42-48 (in Russian).

V. Russak. 1990. Solar radiation. In: Climate of Tartu and its changes during recent decades. IAA, Estonian Acad. Sci., Tartu, 51-78 (in Estonian).

V. Russak. 1990. Long-term changes in solar radiation. In: Climate of Tartu and its changes during recent decades. IAA, Estonian Acad. Sci., Tartu, 79-88 (in Estonian).

V. Russak. 1990. Cloudiness. In: Climate of Tartu and its changes during recent decades. IAA, Estonian Acad. Sci., Tartu, 89-100 (in Estonian).

V. Russak. 1990. The influence of high clouds on the transfer of solar radiation. In: Climate of Tartu and its changes during recent decades. IAA, Estonian Acad. Sci., Tartu, 101-108 (in Estonian).

R. Kivi, V. Russak. 1990. Precipitation. In: Climate of Tartu and its changes during recent decades. IAA, Estonian Acad. Sci., Tartu, 137- 156 (in Estonian).

V. Russak. 1989. Atmospheric transparency at Tõravere. Preprint A-2(2989). IAA, Acad. Sci. Est. SSR, Tartu, 54 pp (in Russian).

V. K. Russak. 1988. Decline of atmospheric transparency and decrease of solar radiation in Tartu. In: Transfer of optical waves in the atmosphere and adaptive optics. Acad. Sci. USSR, Tomsk, 52-55 (in Russian).

V. K. Russak. 1987. On modern changes in atmospheric transparency. Meteorologiya i gidrologiya, 3, 53-57 (in Russian).

V. Russak. 1987. Radiation regime at Tõravere. Preprint A-7(1987). IAA, Acad. Sci. Est. SSR, Tallinn, 52 pp (in Russian).

V.K. Russak. 1987. Modern variations of atmospheric transparency. Soviet Meteorol. and Hydrol. 1987, No 3, 40-44.

V. Russak. 1986. Radiation climate in Estonia. In: Academy of Sciences of the Estonian SSR in 1980-1985. Valgus, Tallinn, 90-91 (in Estonian).

V.K. Russak, R. G. Timanovskaya. 1984. Variability of short-wave radiation in the presence of broken clouds. In: Radiation in a cloudy atmosphere. Atmospheric Sciences Library Series, Vol. 6, Ed. E. M. Feigelson, D. Reidel Publishing Company, Dordrecht-Boston-Lancaster, 302 p.

V.K. Russak. 1984. Peculiarities of the cloudiness and radiation regime in Tartu. In: Proceedings of the XII workshop on actinometry, Irkutsk, 85-87 (in Russian).

V. Põldmaa. 1981. Radiation regime of the Baltic Sea. In: The investigation and modelling of processes in the Baltic Sea, II, ITE, Acad. Sci. Est. SSR, Tallinn, 81-92.

A.E. Kuusk, Ü.-A.R. Mullamaa, H.A. Ohvril, V.K. Põldmaa, M. A. Sulev. 1981. Theoretic-experimental model of statistical structure. In: Radiation in a cloudy atmosphere. Ed. by E. M. Feigelson, Gidrometeoizdat, Leningrad, 32-40 (in Russian, the English translation: Atmospheric Sciences Library Series, v. 6, Reidel Publishing Company, Dordrecht-Boston-Lancaster).

V. K. Põldmaa, R. G. Timanovskaya. 1981. Variability of short- wave radiation fluxes in case of broken clouds. In: Radiation in a cloudy atmosphere. Ed. by E. M. Feigelson, Gidrometeoizdat, Leningrad, 183-186 (in Russian, the English translation: Atmospheric Sciences Library Series, v.6, Reidel Publishing Company, Dordrecht-Boston-Lancaster).

Ü. Kährik, H. Ohvril, V. Põldmaa. 1980. On the radiation regime variability during JASIN"78". JASIN News, 17, Inst. Ocean. Sci., Wormley, England, 3-6.

V.K. Põldmaa. 1978. The ratio of direct to diffuse radiation on the earth's surface. In: Variability of cloudiness and radiation fields. IAA, Acad. Sci. Est. SSR., Tartu, 50-61 (in Russian).

V.K. Põldmaa. 1978. The temperature of ground surface in the presence of Cu clouds. In: Variability of cloudiness and radiation fields. IAA, Acad. Sci. Est. SSR, Tartu, 105-112 (in Russian).

V.K. Põldmaa. 1975. On the methods of normalizing the fluxes of short-wave radiation. In: Cloudiness and radiation. IAA, Acad. Sci. Est. SSR, Tartu, 89-96 (in Russian).

Ü.-A.R. Mullamaa, V.K. Põldmaa, 1975. Variability of direct solar radiation. In: Cloudiness and radiation. IAA, Acad. Sci. Est. SSR, Tartu, 97-109 (in Russian).

Ü.-A.R. Mullamaa, V.K. Põldmaa. 1975. Variability of the brightness of the zenith in the presence of Cu clouds. In: Cloudiness and radiation. IAA, Acad. Sci. Est. SSR, Tartu, 110-122 (in Russian).

Ü.-A.R. Mullamaa, V. K. Põldmaa, H.A. Ohvril, 1974. Possibilities of calculation of the radiation fluxes variability from the data of cloudiness and radiation climate. In: Radiation processes in the atmosphere and ground surface. Gidrometeoizdat, Leningrad, 71-73 (in Russian)

Ü.-A.R. Mullamaa, M.A. Sulev, V. K. Põldmaa, H.A. Ohvril, 1974. Variability of radiation balance, albedo and influx of short-wave radiation in presence of broken cloud cover. In: Radiation processes in the atmosphere and ground surface. Gidrometeoizdat, Leningrad, 74-76 (in Russian)

Ü.R. Mullamaa, V.K. Põldmaa, M.A. Sulev. 1972. On the methods of measuring of averaged fluxes of short-wave radiation and cloudiness. In: Heat transfer in the atmosphere. Nauka, Moscow, 87-92 (in Russian).

V.K. Põldmaa. 1972. On the precision of the averaging of global radiation fluxes. In: Heat transfer in the atmosphere, Nauka, Moscow, 93-96 (in Russian).

V.K. Põldmaa, R.G. Timanovskaya. 1972. Global radiation on the ground surface in different cloudiness conditions. In: Heat transfer in the atmosphere, Nauka, Moscow, 101-106 (in Russian).

Ü.R. Mullamaa, V.K. Põldmaa, M.A. Sulev. 1972. Structure of the Cu-clouds field. In: Heat transfer in the atmosphere, Nauka, Moscow, 126-129 (in Russian).

Ü.-A.R. Mullamaa, M.A. Sulev, V.K. Põldmaa, H.A. Ohvril, H. J. Niilisk, M. I. Allenov, L. G. Chubakov, A. E. Kuusk. 1972. Stochastic structure of cloud and radiation fields. Ed. by Ü.-A. R. Mullamaa. IPA, Acad. Sci. Est. SSR, Tartu, 282 pp (in Russian, the English translation: 1975, NASA TT F-822, Washington D.C.).

V. K. Põldmaa, R. G. Timanovskaya. 1969. Some statistical parameters of total radiation for cloudy conditions. Izvestiya AN SSR, FAO, V, 5, 457-462 (in Russian).

Ü.-A. Mullamaa, M. Sulev, V. Põldmaa. 1969. About statistical characteristics of radiation field in the presence of clouds. In: Radiation and cloudiness. IPA, Acad. Sci. Est. SSR, Tartu, 130-154 (in Russian).

V. Põldmaa. 1969. The atmosphere transparency at Tõravere. In: Radiation in the atmosphere. IPA, Acad. Sci. Est. SSR, Tartu, 5-16 (in Russian).

G. V. Rosenberg, V. K. Põldmaa. 1969. Sky brightness in the mesosphere. Izvestiya AN SSSR, FAO, V, 6, 636-637 (in Russian).

V. Põldmaa. 1967. Twilight-sky brightness. In: Investigations of the atmospheric radiation regime.IPA, Acad. Sci. Est. SSR, Tartu, 110- 132 (in Russian).

V. Põldmaa. 1967. On the soundings of the atmosphere by the twilight method. Proceedings of Acad. Sci. Est. SSR,XVI, 3, 337-344 (in Russian).

G. V. Rosenberg, A. B. Sandomirsky and V. K. Põldmaa. 1967. Measurements of altitude variation of scattering coefficient in stratosphere. In: Noctilucent clouds, Tallinn, 86-94.

V. K. Põldmaa, G. V. Rosenberg. 1966. Some results of twilight atmosphere soundings and of studying its possibilities. Izvestiya AN SSSR, FAO, II, 8, 820-834 (in Russian).

V. Põldmaa. 1966. On high-order scattering in twilight. Proceedings of Acad. Sci. Est. SSR, XV, 4, 519-530 (in Russian).

V. K. Põldmaa. 1966. Principles of the twilight studies. Cand. Thesis in Phys.-Maths. Tartu State University, Tartu, 18pp (in Russian).

V. K. Põldmaa. 1965. Interpretation of twilight sky brightness. Izvestiya AN SSSR, FAO, I, 11, 1168-1177 (in Russian).

V. Põldmaa. 1964. Twilight sky spectrophotometer. Proceedings of Acad. Sci. Est.SSR, XIII, 3, 192-199 (in Russian).

V. Põldmaa. 1963. On distribution of diffuse radiation over the sky. In: Investigations in atmospheric physics. IPA, Acad. Sci. Est. SSR, 4, 111-119 (in Russian).

V. Kannes, I. Nei, A. Raik. 1957. On the influence of south cyclones on the weather conditions in Estonia. In: Annual of the Estonian Geographical Society 1957. Acad. Sci. Est. SSR, Tallinn, 149- 167 (in Estonian).