T. Baranyi - Academia.edu (original) (raw)

Papers by T. Baranyi

The Astrophysical Journal, 2016

The determination of the area of sunspots is of high importance from several points of view, i.e.... more The determination of the area of sunspots is of high importance from several points of view, i.e. evolution of sunspots , their effect on solar irradiance. Nowadays, the new automated sunspot area measurements start to replace the time consuming, hand-made measurements. In addition, the ground-based solar observations are supplemented by observations from space. However, the resolution of the ground based

Parameters of compactness and asymmetry are defined to study the differences in the dismemberment... more Parameters of compactness and asymmetry are defined to study the differences in the dismemberment of the leading and following parts of sunspot groups. The asymmetry may have implications on the interactions of magnetic and velocity fields.

Several recent advances have been made in the procedure and presentation of the Debrecen Photohel... more Several recent advances have been made in the procedure and presentation of the Debrecen Photoheliographic Data. We summarize the present status of the catalogue, and the available forms of the access to the data and images of sunspot groups. We also report the present and further steps to speed up the procedure of evaluation.

The Astrophysical Journal, 2014

The annual/semiannual behaviour of monthly mean of B z component of interplanetary magnetic field... more The annual/semiannual behaviour of monthly mean of B z component of interplanetary magnetic field (IMF) separated by positive and negative B y components were studied. The study was confined to the ascending phases of the four recent sunspot cycles when interplanetary counterparts of coronal mass ejections (ICMEs) dominate among the sources of geoeffectiveness. Definite differences were found between the annual variations of the monthly mean B z values of geoeffective (Kp > 3) ICMEs. When the solar dipole is parallel to the terrestrial one, the Russell-McPherron effect is detectable in the opposite annual variations of the mean GSM B z as is expected. However, when the solar and terrestrial dipoles are antiparallel, the mean B z does not exhibit the Russell-McPherron effect in the GSM (Geocentric Solar Magnetospheric) system because there are strong inverse annual variations in the GSE (Geocentric Solar Ecliptic) system. This kind of smaller minima of the curves of mean GSE B z during the antiparallel years indicate that the ICMEs may have much stronger negative GSE B z values during these years. The southern excess may come from the large-scale north-south asymmetries of the heliospheric magnetic field or from the characteristics of magnetic clouds (direction of the axial field or polarities of the leading and trailing fields).

The annual behaviour of monthly number of hours spent by the Earth in domains of either positive ... more The annual behaviour of monthly number of hours spent by the Earth in domains of either positive or negative B y component of the interplanetary magnetic field (IMF) was studied. We used the hourly OMNI data in the cases of Kp>3. The study was confined to the ascending phases of the four recent sunspot cycles when Interplanetary Coronal Mass Ejections (ICMEs) dominate among the sources of geoeffectiveness. Definite differences were found between the annual variations of the hourly sums. When the solar dipole is opposite to the terrestrial one, the sums exhibit the the combined effect of Rosenberg-Coleman and Russell-McPherron effects. Thus, in the geomagnetically active hours the negative B y dominates during the first half of the year and the positive B y dominates during the second half of the year. However, these effects can not be detected in the occurrence of the negative and positive GSM B y values when the solar and terrestrial dipoles are parallel. In this case one can see polarity-independent semiannual variations instead of the polarity-dependent opposite annual variations. It is well-known that the B y component modulates the energy transfer from the solar wind to the magnetosphere causing marked asymmetries in magnetospheric convective flow pattens at high latitudes. Our results hint that the occurrences of these asymmetries related to the ICMEs depend on the solar dipole cycle. In the antiparallel years one of them dominates during half a year causing asymmetric energy transfer to the magnetosphere. In the parallel years the occurrences of the two kind of asymmetries are equal on monthly time scale, thus the energy transfer is symmetric within a monthly and yearly time interval.

ABSTRACT The goal of this paper is to examine the evolution of sunspots and their relation to sol... more ABSTRACT The goal of this paper is to examine the evolution of sunspots and their relation to solar irradiance variations based on the sunspot data archive of the Heliophysical Observatory of the Hungarian Academy of Sciences. Long-term full-disk white-light observations have been made at the Debrecen Heliophysical Observatory and its Gyula observing station. Using observations from other observatories when they are not availabe in this archive is being used to complete a sunspot catalogue as a continuation of the Greenwich Catalogue and to provide a homogeneuous data base of the area and position of sunspots covering a century long time interval. As part of the measurement process, the photoheliograms are digitized and resolved into a 8K×8K matrix, which allows to measure and catalogue the area and position of sunspots (both umbra and penumbra) with high accuracy. These sunspot data are published in the Debrecen Photoheliographic Data catalogue (DPD). Since 1996, the SOHO/MDI intensity images have also been processed and analyzed in the same way as the DPD images and these MDI sunspot area and position data are published in the SOHO/MDI -- Debrecen Data (SDD) catalogue. In addition to the MDI intensity images, the MDI magnetograms are used to gather information about the average magnetic field strength values and polarities of the investigated sunspot umbra and penumbra.Considering the availability of the high time cadence MDI observations, we are able to study the evolution of sunspots in detail. In this paper we concentrate on the time frame of 1996 to 1997, when individual sunspot groups can be well-separated and their effect on solar irradiance can be studied in detail.

The solar active longitudes were studied in the northern hemisphere in cycles 22 and 23 by using ... more The solar active longitudes were studied in the northern hemisphere in cycles 22 and 23 by using data of DPD sunspot catalogue. The active longitudes are not xed in the Carrington system, they have a well recognizable migration path between the descending phase of cycle 21 (from about 1983) and ascending phase of cycle 23 (until about 1996), out of this interval the migration path is ambiguous. The longitudinal distribution on both sides of the path has been computed and averaged for the length of the path. The so-called ip-op phenomenon, when the activity temporarily gets to the opposite longitude, can also be recognized. The widths of the active domains are fairly narrow in the increasing and decaying phases of cycle 22, their halfwidths are about 20 • − 30 • for both the main and secondary active belts but it is more at and stretched around the maximum with a halfwidth of about 60 • .

The temporal behaviour of solar active longitudes has been examined by using two sunspot catalogu... more The temporal behaviour of solar active longitudes has been examined by using two sunspot catalogues, the Greenwich Photoheliographic Results (GPR) and the Debrecen Photoheliographic Data (DPD). The time-longitude diagrams of the activity distribution reveal the preferred longitudinal zones and their migration with respect to the Carrington frame. The migration paths outline a set of patterns in which the activity zone has alternating prograde/retrograde angular velocities with respect to the Carrington rotation rate. The time proles of these variations can be described by a set of successive parabolae. Two similar migration paths have been selected from these datasets, one northern path during cycles 21 22 and one southern path during cycles 13 14, for closer examination and comparison of their dynamical behaviours. The rates of sunspot emergence exhibited in both migration paths similar periodicities, close to 1.3 years. This behaviour may imply that the active longitude is connected to the bottom of convection zone.

The Astrophysical Journal, 2016

The determination of the area of sunspots is of high importance from several points of view, i.e.... more The determination of the area of sunspots is of high importance from several points of view, i.e. evolution of sunspots , their effect on solar irradiance. Nowadays, the new automated sunspot area measurements start to replace the time consuming, hand-made measurements. In addition, the ground-based solar observations are supplemented by observations from space. However, the resolution of the ground based

Parameters of compactness and asymmetry are defined to study the differences in the dismemberment... more Parameters of compactness and asymmetry are defined to study the differences in the dismemberment of the leading and following parts of sunspot groups. The asymmetry may have implications on the interactions of magnetic and velocity fields.

Several recent advances have been made in the procedure and presentation of the Debrecen Photohel... more Several recent advances have been made in the procedure and presentation of the Debrecen Photoheliographic Data. We summarize the present status of the catalogue, and the available forms of the access to the data and images of sunspot groups. We also report the present and further steps to speed up the procedure of evaluation.

The Astrophysical Journal, 2014

The annual/semiannual behaviour of monthly mean of B z component of interplanetary magnetic field... more The annual/semiannual behaviour of monthly mean of B z component of interplanetary magnetic field (IMF) separated by positive and negative B y components were studied. The study was confined to the ascending phases of the four recent sunspot cycles when interplanetary counterparts of coronal mass ejections (ICMEs) dominate among the sources of geoeffectiveness. Definite differences were found between the annual variations of the monthly mean B z values of geoeffective (Kp > 3) ICMEs. When the solar dipole is parallel to the terrestrial one, the Russell-McPherron effect is detectable in the opposite annual variations of the mean GSM B z as is expected. However, when the solar and terrestrial dipoles are antiparallel, the mean B z does not exhibit the Russell-McPherron effect in the GSM (Geocentric Solar Magnetospheric) system because there are strong inverse annual variations in the GSE (Geocentric Solar Ecliptic) system. This kind of smaller minima of the curves of mean GSE B z during the antiparallel years indicate that the ICMEs may have much stronger negative GSE B z values during these years. The southern excess may come from the large-scale north-south asymmetries of the heliospheric magnetic field or from the characteristics of magnetic clouds (direction of the axial field or polarities of the leading and trailing fields).

The annual behaviour of monthly number of hours spent by the Earth in domains of either positive ... more The annual behaviour of monthly number of hours spent by the Earth in domains of either positive or negative B y component of the interplanetary magnetic field (IMF) was studied. We used the hourly OMNI data in the cases of Kp>3. The study was confined to the ascending phases of the four recent sunspot cycles when Interplanetary Coronal Mass Ejections (ICMEs) dominate among the sources of geoeffectiveness. Definite differences were found between the annual variations of the hourly sums. When the solar dipole is opposite to the terrestrial one, the sums exhibit the the combined effect of Rosenberg-Coleman and Russell-McPherron effects. Thus, in the geomagnetically active hours the negative B y dominates during the first half of the year and the positive B y dominates during the second half of the year. However, these effects can not be detected in the occurrence of the negative and positive GSM B y values when the solar and terrestrial dipoles are parallel. In this case one can see polarity-independent semiannual variations instead of the polarity-dependent opposite annual variations. It is well-known that the B y component modulates the energy transfer from the solar wind to the magnetosphere causing marked asymmetries in magnetospheric convective flow pattens at high latitudes. Our results hint that the occurrences of these asymmetries related to the ICMEs depend on the solar dipole cycle. In the antiparallel years one of them dominates during half a year causing asymmetric energy transfer to the magnetosphere. In the parallel years the occurrences of the two kind of asymmetries are equal on monthly time scale, thus the energy transfer is symmetric within a monthly and yearly time interval.

ABSTRACT The goal of this paper is to examine the evolution of sunspots and their relation to sol... more ABSTRACT The goal of this paper is to examine the evolution of sunspots and their relation to solar irradiance variations based on the sunspot data archive of the Heliophysical Observatory of the Hungarian Academy of Sciences. Long-term full-disk white-light observations have been made at the Debrecen Heliophysical Observatory and its Gyula observing station. Using observations from other observatories when they are not availabe in this archive is being used to complete a sunspot catalogue as a continuation of the Greenwich Catalogue and to provide a homogeneuous data base of the area and position of sunspots covering a century long time interval. As part of the measurement process, the photoheliograms are digitized and resolved into a 8K×8K matrix, which allows to measure and catalogue the area and position of sunspots (both umbra and penumbra) with high accuracy. These sunspot data are published in the Debrecen Photoheliographic Data catalogue (DPD). Since 1996, the SOHO/MDI intensity images have also been processed and analyzed in the same way as the DPD images and these MDI sunspot area and position data are published in the SOHO/MDI -- Debrecen Data (SDD) catalogue. In addition to the MDI intensity images, the MDI magnetograms are used to gather information about the average magnetic field strength values and polarities of the investigated sunspot umbra and penumbra.Considering the availability of the high time cadence MDI observations, we are able to study the evolution of sunspots in detail. In this paper we concentrate on the time frame of 1996 to 1997, when individual sunspot groups can be well-separated and their effect on solar irradiance can be studied in detail.

The solar active longitudes were studied in the northern hemisphere in cycles 22 and 23 by using ... more The solar active longitudes were studied in the northern hemisphere in cycles 22 and 23 by using data of DPD sunspot catalogue. The active longitudes are not xed in the Carrington system, they have a well recognizable migration path between the descending phase of cycle 21 (from about 1983) and ascending phase of cycle 23 (until about 1996), out of this interval the migration path is ambiguous. The longitudinal distribution on both sides of the path has been computed and averaged for the length of the path. The so-called ip-op phenomenon, when the activity temporarily gets to the opposite longitude, can also be recognized. The widths of the active domains are fairly narrow in the increasing and decaying phases of cycle 22, their halfwidths are about 20 • − 30 • for both the main and secondary active belts but it is more at and stretched around the maximum with a halfwidth of about 60 • .

The temporal behaviour of solar active longitudes has been examined by using two sunspot catalogu... more The temporal behaviour of solar active longitudes has been examined by using two sunspot catalogues, the Greenwich Photoheliographic Results (GPR) and the Debrecen Photoheliographic Data (DPD). The time-longitude diagrams of the activity distribution reveal the preferred longitudinal zones and their migration with respect to the Carrington frame. The migration paths outline a set of patterns in which the activity zone has alternating prograde/retrograde angular velocities with respect to the Carrington rotation rate. The time proles of these variations can be described by a set of successive parabolae. Two similar migration paths have been selected from these datasets, one northern path during cycles 21 22 and one southern path during cycles 13 14, for closer examination and comparison of their dynamical behaviours. The rates of sunspot emergence exhibited in both migration paths similar periodicities, close to 1.3 years. This behaviour may imply that the active longitude is connected to the bottom of convection zone.