A POSSIBLE EFFECT OF THE SOLAR ACTIVITY ON ATMOSPHERIC OZONE CONTENT

Increases of atmospheric ozone content were observed in March 1989 at Beijing, China. This is possible result of disturbance by the great solar flares. The mechanism is simply discussed in this paper.     

PERIODICITIES IN THE NORTH–SOUTH ASYMMETRY OF THE SOLAR DIFFERENTIAL ROTATION AND SURFACE MAGNETIC FIELD

We have studied the temporal variations in the north–south asymmetries of the differential rotation parameters A, B, and the mean rotation rate , by determining their values from Greenwich data for sunspot groups (1879–1976) in the northern and southern hemispheres, during moving time intervals of lengths 3 yr and 5 yr, successively displaced by 1 yr. The variation in the north–south asymmetry ( ) of is similar to the variation in the asymmetry (B ) of B but with opposite sign. These variations of and B may represent components of an anti-symmetric torsional oscillation which are in opposite phase with each other.The FFT and MEM analyses of the temporal variations of B , , and the north–south asymmetry (A ) of A, show existence of significant periodicities: 45.5 ± 11.5 yr,21.3 ± 4.5 yr, 13.3 ± 1.5 yr, and 10.5 ± 0.5 yr. These analyses also show a few other possible periodicities in A , B , and . All these periodicities are also seen in the north–south asymmetry of sunspot activity (with similar relative magnitudes). The 22-yr periodicity was seen in even-parity modes of magnetic field inferred from sunspot data.     

ANALYSIS OF 2D Hα SPECTRA AND MAGNETIC FIELD DURING THE IMPULSIVE PHASE OF A SOLAR FLARE

We obtained a set of well-observed 2D H spectral data of a 1N/M1.5 flare from the Solar Tower of Nanjing University. Using the H spectra, the sites of electron precipitation and high coronal pressure have been found, and the Doppler velocity was calculated from the red asymmetry of the H emission line by use of the bisector method. The current density distribution was also computed from magnetic field measurements. We have coaligned the H spectroheliograms and the magnetograms. It was found that the sites of electron precipitation were at the edge of a main current area. The sites of red asymmetry coincided with those of high coronal pressure. The flare reached its maximum in the magnetic shear region, though it began in a weak magnetic field. Several flare models are discussed to see which one could satisfy the observation.     

AR5395:OBSERVATIONS ON THE ASYMMETRIES OF THE Hα AND CaⅡ K LINE PROFILES OF THE FLARES ON MARCH 9 AND 14,1989

The most powerful method to diagnose the velocity field in solar flare atmosphere isspectral analyses. That is to analyse the asymmetry and the Doppler shift of flare spectralline profiles. Recent observations indicated that at the impulsive phase of flares thereare obvious red asymmetry of Hα profiles and a downward velocity of 40-100km/s has