Zobrazeno 1 - 10
of 152
pro vyhledávání: '"R. Pirjola"'
Publikováno v:
Annales Geophysicae, Vol 27, Pp 1775-1787 (2009)
In this paper, we analyse in detail two famous space weather events; a railway problem on 13–14 July 1982 and a power blackout on 30 October 2003. Both occurred in Sweden during very intensive space weather storms and each of them a few years af
Externí odkaz:
https://doaj.org/article/12990e59eb7840feac24b3823b33fb0e
Publikováno v:
Advances in Geosciences, Vol 3, Pp 23-27 (2005)
The term space weather is used for the solar driven variability in particle and electromagnetic conditions of the near-Earth space that may harm the performance of ground-based and space-borne technology. The European Union (EU) and the European Spac
Externí odkaz:
https://doaj.org/article/2dd55f12e1c24803bd3a5341af671710
Autor:
M. Uspensky, A. Koustov, P. Janhunen, E. Nielsen, K. Kauristie, O. Amm, R. Pellinen, H. Opgenoorth, R. Pirjola
Publikováno v:
Annales Geophysicae, Vol 22, Pp 1077-1091 (2004)
Four evening events and one morning event of joint EISCAT/STARE observations during ~22h are considered and the differences between observed STARE line-of-sight (l-o-s) velocities and EISCAT electron drift velocities projected onto the STARE beams
Externí odkaz:
https://doaj.org/article/b4592f37616a4bb7a095f3c35d36bafc
Publikováno v:
Annales Geophysicae, Vol 22, Pp 101-113 (2004)
The method of spherical elementary current systems provides an accurate modelling of the horizontal component of the geomagnetic variation field. The interpolated magnetic field is used as input to calculate the horizontal geoelectric field. We us
Externí odkaz:
https://doaj.org/article/a38e91eeb2354d36b2f55085bf9743e5
Publikováno v:
Annales Geophysicae, Vol 22, Pp 63-72 (2004)
To learn about the geometry and sources of the ionospheric current systems which generate strong geomagnetically induced currents, we categorize differential equivalent current systems (DEC) for events with strong dB/dt by decomposing them into th
Externí odkaz:
https://doaj.org/article/f6413a41e47948c5a99653a1c8b5887f
Autor:
M. V. Uspensky, A. V. Koustov, P. Eglitis, A. Huuskonen, S. E. Milan, T. Pulkkinen, R. Pirjola
Publikováno v:
Annales Geophysicae, Vol 19, Pp 411-424 (2001)
A short event of high-velocity E-region echo observations by the Pykkvibaer HF radar is analysed to study echo parameters and the echo relation to the Farley-Buneman plasma instability. The echoes were detected in several beams aligned closely t
Externí odkaz:
https://doaj.org/article/78bf8ca3483f4b7fa5e28277b494f6fa
Autor:
R. Pirjola, A. Viljanen
Publikováno v:
Annales Geophysicae, Vol 16, Pp 1434-1444 (1998)
The electromagnetic field due to ionospheric currents has to be known when evaluating space weather effects at the earth's surface. Forecasting methods of these effects, which include geomagnetically induced currents in technological systems, are
Externí odkaz:
https://doaj.org/article/2a11ddc7c0104ddea478e189f0b5bab7
Publikováno v:
Annales Geophysicae. 40:205-215
The need for accurate assessment of the geomagnetic hazard to power systems is driving a requirement to model geomagnetically induced currents (GIC) in multiple voltage levels of a power network. The Lehtinen–Pirjola method for modelling GIC is wid
Publikováno v:
IEEE Access, Vol 7, Pp 147029-147037 (2019)
Geomagnetic field variations produce geoelectric fields that can affect the operation of technological networks at the Earth's surface, including power systems, pipelines, phone cables and railway circuits. To assess the geomagnetic hazard to this te
Autor:
L. R. Alves, Cleiton S. Barbosa, Ari Viljanen, Ramon Caraballo, Gelvam A. Hartmann, Chigomezyo M. Ngwira, Andrés R. R. Papa, R. Pirjola, Ciaran Beggan
Publikováno v:
Space Weather. 15:1094-1101
Geomagnetically induced currents (GICs) have been long recognized as a ground effect arising from a chain of space weather events. GICs have been measured and modeled in many countries, resulting in a considerable amount of data. Previous statistical