289 Forbush Decrease effects (FD) were processed, for 207 of which corresponding flares were determined. The following parameters of FDs were determined from cosmic ray recordings at the Alert station: start of FD, time of first or second minimum value, the time lag of the beginning of FD behind the source flare, the
duration of the descending phase, the decrease of FD in per cent, the duration of the whole decrease effect and the rate of decline phase. The occurrence of FDs in the years of solar cycle No. 21 and the distribution of source flares over the solar disc was demonstrated (including NS oř EW asymmetry). In the II part will be
published the statistical distribution of the individual parameters of FDs and their mutual relations. The values of the FD parameters are also related to the importance and also to the longitudinal position of the flares. Some results of studied relations were used for interpretations of the characteristics and shape of the magnetic plasma cloud.
An exceptional 10-hour enhancement in the level of the soft X-ray emission, most probably originated in an exceptionally active region with flares at the eastern limb of the disk on Jan. 25, 1981, is described. This phonomenon has been called "an outstanding
X-ray emission of an active region" (1984) and is documented by measurements made independently on two probes, i.e. GEQS-2 and PROGNOZ-8. The rise in the level of the X-ray emission (2-8 keV) amounted to about one order of magnitude (from l10^-6 to 10^-5 Wm^-2). The separate emission of flares are superimposed on this large enhancement. During the event, 3 outbursts were recorded int the 80 - 160 keV range, in each case at the time of recurrent flares in the region at the E limb (S 14, E 90) (Křivský and Scheirich, 1984). The most significant flares of this period were recorded by the coronograph on Lomnický štít. The flare had the form of ascending flare loops, at the sides of which ejections towards the corona or arcs receding to the disk could be observed. Radio burst of type IV and II occurred in the explosive phase of the flare, as well as a hard X-ray emission burst within the same interval in which bright flare loops were generated at the very beginning, and when partlcle acceleration apparently occurred. The fast particles were not recorded on the Earth due to its unfavourable position relative to their source and trajectory, but after 17:00 UT the X-ray photometer aboard the Prognoz-8 satellite registered a large number of unresolved fast particles (see Fig. 3). The studied phenomenon belongs to the interval of the Solar Maximum Year (Aug. 1979 - Feb. 1981).
This Paper is a continuation of four proceeding lists, which contained flares observed at Ondřejov since 1948 up to the end of June, 1957. This list presents data abour 727 flares, associated 536 Mc/s outburst, and atmospheries observed and recorded during the I. G. Y. Curves of the H2 line-width changes for all these flares are plotted in Fig. 1-15.
Historical comments about identification of solar X-emission of various events and recent examples, especially of long-range emission from active regions, are presented
The authors have attempted to elucidate a problem which has widely been discussed in recent years, i. e. the ftuctuation of the solar activity in the past centuries, i. e. from the year 1 000 to the end of the I9th century; for this purpose, they have used a catalogue of auroral observations compiled from all the catalogues (or their corrections) hitherto published, sets of observations and their own supplement of hitherto uncatalogized or unknown observations of the aurorae, extracted from the most various historical sources found in the Czech Lands. The supplement contains 91 aurorae from Bohemia and is presented in Part I. This catalogue gives the ordinal number of the aurora, the date, the description in the original language and the English translation. The world catalogue and its elaboration which regard to long-term variations of aurorae is in Part II, and contains 3 878 northern aurorae from latitudes < 55°N. Part III deals with the relation between the fluctuations of the secular solar activity, in terms of occurrence of aurorae, and the fluctuations of the climate, with particular regard to Central Europe and Bohemia. and Článek převzat z Travaux Géophysiques XXXIII (1985), s. 79-151
I. The mean state of circulation in some of the months can be demonstrated by the mean position of the frontal zone. From the position of the frontal zone we can determine if the zonal or meridional circulation prevails, and in which way it will change during the year
II. The long-range variation of the mean frontal zone in relation to solar activity expressed by Ejgenson s Index of Recurrency of Sunspots A is determined. The effect ascertained is especially significant in January. The results in maps show the deviations of frequencies of the zones from the mean state, partly in the years of minima, partly in the years of maxima of the recurrency of sunspots.