Area of polar coronal holes and sunspot activity: Years 1939–1993     

I. Dorotovič 《Solar physics》1996,167(1-2):419-426

The correlation between the size of polar coronal holes and sunspot numbers has been investigated for the last five solar cycles. The area of polar coronal holes over the period from 1939 to 1993 was derived from ground-based observations of the green coronal line at 530.3 nm (Fe xiv). Correlation analysis revealed that there is no general shift in the maxima of the curves of these two solar indices. The analysis showed the same shift in months in cycles 21 and 22 when the best correlation between the indices is reached; the time shift found in cycle 20 is slightly different from that in cycle 18; in cycle 19, there is found a shift with a value between the values in cycles 18, 20 and 21, 22. The time between succesive peaks of smoothed polar hole size and smoothed sunspot number is different in each cycle.  相似文献   

Long-Term Dynamics of the Large-Scale Magnetic Structures     

P. Ambrož 《Solar physics》2004,224(1-2):61-68

Large-scale magnetic field regions are evolving on a time scale of many weeks and months and are also modified during the solar activity cycle. The position of the regions are compared in a pair of consecutive synoptic charts and the horizontal velocity field responsible for their position changes, is inferred. Besides the axially symmetric zonal and meridional drifts, relating to differential rotation and meridional circulation, also non-axially symmetric velocity structures were observed during the last three solar activity cycles. Changes of the position and spatial distribution, as well as temporal variations of the field strength, closely relate to the occurrence and variations of other forms of solar activity such as sunspots, filaments and prominences and coronal structures. In combination with 11-yr cyclic changes of the large-scale velocity field, a new global dynamic regime of the convection zone is described.  相似文献   

Multi-Wavelength Analysis of the 29 September 2002 M2.6/2N Flare     

Kulinová  Alena  Dzifčáková  Elena  Bujňák  Rastislav  Karlický  Marian 《Solar physics》2004,221(1):101-119

Using TRACE EUV 171 Å line, Hα line, Zürich radio, RHESSI, and HXRS observations the 29 September 2002 flare (M2.6), which occurred in AR NOAA 0134, was analyzed. Flaring structures were compared with a potential magnetic field model (field lines and quasi-separatrix layers) made from SOHO/MDI full-disk magnetogram. Series of high-resolution SOHO/MDI magnetograms and TRACE white-light images were used to find changes in the active region at the photosphere during the flare. The flare began with a rising of a small dark loop followed by the flare brightening observed in 171 Å with TRACE and Hα lines. In radio wavelengths, first type III bursts were observed 5 min prior to the start of hard X-ray emission, indicating a pre-flare coronal activity. The main hard X-ray emission peak (at 06:36 UT) was associated with the second type III burst activity and several slowly negatively drifting features, all starting from one point on the radio spectrum (probably a shock propagating through structures with different plasma parameters). After this time a huge loop formed and three minutes later it became visible in absorption both in Hα and 171 Å EUV lines. The phase of huge dark loop formation was characterized by long-lasting, slowly negatively drifting pulsations and drifting continuum. Finally, considering this huge loop as a surge an evolution of the event under study is discussed.  相似文献   

An analysis of fog events at Belgrade International Airport     

Katarina Veljović  Dragana Vujović  Lazar Lazić  Vladan Vučković 《Theoretical and Applied Climatology》2015,119(1-2):13-24

  相似文献   

Adjustment to rainfall measurement undercatch with a tipping-bucket rain gauge using ground-level manual gauges   总被引：1，自引：0，他引：1  

G. B. Mekonnen  S. Matula  F. Doležal  J. Fišák 《Meteorology and Atmospheric Physics》2015,127(3):241-256

  相似文献   

IAU MDC Photographic Meteor Orbits Database: Version 2013     

L. Neslušan  V. Porubčan  J. Svoreň 《Earth, Moon, and Planets》2014,111(3-4):105-114

A new 2013 version of the IAU MDC photographic meteor orbits database which is an upgrade of the current 2003 version (Lindblad et al. 2003, EMP 93:249–260) is presented. To the 2003 version additional 292 orbits are added, thus the new version of the database consists of 4,873 meteors with their geophysical and orbital parameters compiled in 41 catalogues. For storing the data, a new format enabling a more simple treatment with the parameters, including the errors of their determination is applied. The data can be downloaded from the IAU MDC web site: http://www.astro.sk/IAUMDC/Ph2013/  相似文献   

Spectral,Photometric, and Dynamic Analysis of Eight Draconid Meteors     

Jiří Borovička  Pavel Koten  Lukáš Shrbený  Rostislav Štork  Kamil Hornoch 《Earth, Moon, and Planets》2014,112(1-4):15-31

A Draconid meteor shower outburst was observed from on board two scientific aircraft deployed above Northern Europe on 8th October 2011. The activity profile was measured using a set of photographic and video cameras. The main peak of the activity occurred around 20:15 ± 0:0.5 UT which is consistent with the model prediction as well as with the IMO network visual observations. The corrected hourly rates reached a value of almost 350. The brighter meteors peaked about 15–20 min earlier than the dimmer ones. This difference can be explained by different directions of the ejection of the meteoroids from the parent comet. One of the instruments was even able to detect meteors connected with the material ejected from the parent comet before 1900 and thus confirmed the prediction of the model, although it was based on uncertain pre-1900 cometary data. Another small peak of the activity, which was caused by material ejected during the 1926 perihelion passage of the parent comet, was detected around 21:10 UT. The mass distribution index determined using the narrow field-of-view video camera was 2.0 ± 0.1. This work shows that the observation of meteor outbursts can constrain the orbital elements, outgassing activity and existence of jets at the surface of a comet.  相似文献   

Fourth National Conference of Czechoslovak Geophysicists     

Vincenc Vyskočil 《Studia Geophysica et Geodaetica》1962,6(2):206-207

  相似文献   

A New Determination of the Mass of (1) Ceres     

A. Kovačević  M. Kuzmanoski 《Earth, Moon, and Planets》2007,100(1-2):117-123

We present result for the mass of (1) Ceres, determined from its close encounter with asteroid (5303) Parijskij. Gravitational effects of (1) Ceres on the motion of (5303) Parijskij is the largest found so far. Also, we analyzed available data of close encounter with (7298) 1992 WM5.  相似文献   

Favourable Magnetic Field Configurations for Generation of Flare-Associated Meter-Wave Type III Radio Bursts     

A. Hofmann  V. Ruždjak 《Solar physics》2007,240(1):107-119

Magnetic field structures of Hα flares associated with meter-wave type III bursts during periods of low solar activity in 1975 – 1977 and 1985 – 1987 were investigated. In a statistical analysis it was confirmed that the association rate depends less on flare importance than on brightness. For subflares (95% of the sample), the location of the Hα flare in the bipolar pattern turned out to be crucial for the association rate. It is almost one order of magnitude larger for flares occurring at the border of the active regions, compared to flares located inside the general bipolar pattern. For selected typical examples of flares, extrapolations of the measured magnetic fields were performed. By matching Hα filtergrams and calculated 3-D structures it was found that the positions at the border where the flares associated with type III bursts occurred were close to open field lines extending into the corona. In most investigated cases intrusions of parasitic polarity were found in the vicinity of the flare locations. The extrapolations showed that subflares located inside the bipolar pattern but have not been associated with type III bursts were covered by dense arcades of magnetic loops.  相似文献