Boris Komitov /selected abstracts of papers
and presentations (1997-2011)
SCHOVE`S SERIES, CENTURAL AND
SUPERCENTURAL VARIATIONS OF SOLAR
ACTIVITY. RELATIONSHIPS BETWEEN THE
MAXIMUMS OF 11 - YEARS ADJACENT CYCLES.
Boris Komitov
On the basis of indirect data for 3rd - 20th century - obtained over
the base of evaluations on the nine degree power scale of 11- year
Schove`s
series cycles, time variations of solar activity has been investigated
for
the above mantioned period of time. As a result
104 and 204 - year cycles of duration, as well as traces of cyclic
variations of 77,88,130 and 350 period of years have been established.A
comparison with the data of radiocarbon contents in ligneous sample has
been
made, and it is evident that the main distinguishing feature,between
Schove`s series and C14 temporary time series,is the absence of
trend and cycles of duration of over 500 years in the data of the first
sample
and their presence in the second one.The validity of the relationship
W2 W1, has been checked,where W1 and W2 are respectively near maximum
Wolf`'s number values for the even and the odd cycles following them,
concerning the investigated period of time i.e.1700 years.On the
grounds of the aforesaid the probability for the breach of order in
that inequality
i.e. the even cycles to be higher than the odd cycles following them,
increasis
at high even cycles. The breach of order is a practically inevitable
event
at the highest even cycles for which near maximum average annual Wolf
's
number values exceed 125 . On the basis of these results an assumtion
has been made that the forthcoming 23rd solar cycle will be weaker in
power
than cycle No 22.
in BULG. GEOPHYS. JOURNAL 1997 v 23 No 1-2
See also /in Bulgarian/ The Violation of
Gnevishev -Ohl Rule...) and the next abstract
AMPLITUDE VARIATIONS OF THE 11 YEAR CYCLE
AND THE CURRENT SOLAR MAXIMUM 23
Boris Komitov
Institute of Astronomy, Bulgarian Academy of
Sciences, P.O. Box 179, 6000 Stara Zagora, Bulgaria;
komitov@mbox.digsys.bg
and
Boncho Bonev
Ritter Astrophysical Research Center, Department of
Physics and Astronomy, University of Toledo,
Toledo, OH 43606; bbonev@astro1.panet.utoledo.edu
Received 2000 August 29; accepted 2001 April 26;
published 2001 May 30
We examined the conditions for violations of the Gnevyshev-Ohl rule,
which states that the even-numbered
11 yr solar cycles have been followed by higher in amplitude
odd-numbered
ones.This regularity has been valid for the last 150 years, but it is
very
likely to be broken in the current 11 yr cycle 23. We used the Schove
series, which includes the main macrocharacteristics of the 11 yr
cycles and
is continuous since the end of the third century. The reliability of
these
data has been discussed. A total of 152 cycles were investigated,
the last onebeing cycle 21 in the International Sunspot Number series.
We showed that there is a well-outlined group of even-numbered 11 yr
cycles
that are very likely to be followed by weaker odd-numbered ones. These
are
the most powerful even cycles, characterized by maximum
monthly smoothed Wolf numbers exceeding 125 and decay times of 6 yr or
more. The main factor for violations of the Gnevyshev-Ohl rule is a very
high maximum of the even-numbered 11 yr cycle. Applied to the present
Hale cycle, which consists of 11 yr cycles 22 and
23, our analysis implies a high probability for violation of the
Gnevyshev-Ohl
rule. The development of 11 yr cycle 23 confirms this conclusion. We
argue that the present 11 yr cycle should not be qualified as
“abnormal”
when referring to the fact that it breaks a regularity that has lasted
for
150 yr. The 11 yr cycle 23 might reveal a feature in the dynamics of
the Hale cycle
that the strongest even-numbered 11 yr cycles are likely to be followed
by
lower amplitude odd-numbered ones. We briefly discuss the relation
between the long-term solar variability and the current violation of the
Gnevyshev-Ohl rule
. The Astrophysical Journal, 554:L000–L000, 2001 June 10
See also Solar Activity Prediction Service
: NEW TWO-VARIABLE FITS FOR THE SCALE-
LENGHTS OF CN AND ITS PARENT
MOLECULE IN COMETARY ATMOSPHERES:
APPLICATION TO THE IDENTIFICATION OF
THE CN-PARENT
Bonev, B.; Komitov, B.
Affiliation:
AA(Bowling Green St. Univ./Univ. of Toledo),
AB(Inst. of Astronomy - Bulgarian Academy of Sciences)
We provide new two-variable fits describing the variability of the Haser
scale lengths of CN and its parent molecules. As in our previous
reports
on this subject we use the heliocentric distance and the 10.7-cm solar
radio flux as independent variables. Such description reduces the error
bars and avoids the systematic behavior observed in the residuals of
the
one-variable fits with only the heliocentric distance. The data for the
CN parent scale length include 56 reported values from different comets
over a period of two solar cycles. On that basis, using the connection
between true and Haser scale lengths, we discuss the possible CN
parents
HCN and C2N2. These two molecules have been separately highlighted in
different papers as the most probable candidates for a major CN parent.
Our two-variable fit implies a brightness distribution of CN which may
be explained under the assumption that the C2N2 molecule is the single
CN parent.
Journal: American Astronomical Society, DPS
meeting #32, #41.05Publication
Date: 10/2000
Origin:AASAbstract Copyright
: (c) 2000: American Astronomical
Society Bibliographic Code:
2000DPS....32.4105B
CCD PHOTOMETRY OF COMET C/1999 S4 (LINEAR) at 387 nm: FIRST RESULTS
Komitov, B.; Bonev, B.; Bonev, T.; Ivanova, A.
Affiliation:
AA(Inst. of Astronomy - Bulgarian Academy of Sciences)
AB(Univ. of Toledo)
AD(Inst. of Astronomy - Bulgarian Academy of Sciences)
CCD observations on comet C/1999 S4 (LINEAR) were done on July 3 and
July 4, 2000 with the 2-meter telescope in the National Astronomical
Observatory "Rozhen", Bulgaria. We used a narrow-band filter centered
at
387 nm. Brightness profiles of CN, which correspond to conditions close
to the current solar maximum, were obtained and analyzed with the Haser
and the vectorial exospheric models. The results are compared with
obtained for
other comets.
Journal of American Astronomical Society, DPS meeting #33,
#41.21Publication Date:10/2000
Origin:AASAbstract Copyright:
(c) 2000: American Astronomical
SocietyBibliographic Code:
2000DPS....32.4121K
AMPLITUDE VARIATIONS OF CENTURIAL AND
BICENTURIAL SOLAR CYCLES
Boris Komitov
The subject of this report is to demonstrate the changes in the power
appearences of the centural and bicenturial solar cycles .
For this purpose two independent series indirect data on the base
of the solar actuvity have been used i.e. :1) Schove's series ,
containing continuous data for the last 1700 years . 2) radiocarbon
tree series for the last 4500 years. Cyclic changes at the amplitudes
of the
two cycles have been established .The amplitude variations are
very big at the bicentural cycle ( T = 205 yrs. ). As a result , about
2300
- year powerful cycle of duration , has been established among them
and also a second one of about 1050 period of years which
is weaker than the first one . In this context, around the deep
minimums of the supercentural solar activity course , as for example
the period XV/ th - XVII/ th century ( between the Sprorer's
and Maunder's minimums ) the bicentural cycle completely dominates
over all the rest , which compete with its variations . In the epochs
which are removed , back or earlier in the time at about 1000 - 1200
years, compared with deep solar minimums the picture is
just the opposite . In connection with these facts the bicentural cycle
is very weak or is completely absent in this epochs . A very weak
dynamics showed also the powerful appearances of the centural cycle .
Their range of varability has an average period of about 1350 years.
paper in 6th National Conferrence of Solar-Terrestrial
Physics,Sofia,1999
THE HISTORICAL PROCESS AS A REFLECTION OF SOLAR-CLIMATIC RELATIONS
Boris Komitov
The purpose of this study is to concider the important role of 2200 -
2400
year solar - climatic cycle on the historical process.The so obtained
conclusions here , confirm " The theory of civillization " by Arnold
Toynbee from the base of a new point of vew.
in Proceedings of Scientific Conference with international
participation
"Stara Zagora 2002", Stara Zagora , June 6-7,2002, Part IV,pp 162-166
SOLAR ACTIVITY VARIATIONS FOR THE LAST MILLENIA:
WILL THE NEXT LONG-PERIOD SOLAR MINIMUM BE FORMED?
Boris Komitov and Vladimir Kaftan
The series of macrocharacteristics of the 11-year Schwabe–Wolf
cycles (the so-called Schowe series) has been used to specify notions
of the character of long-term variations in solar activity.
A mathematical statistic analysis of data in the series has been
performed using two independent methods. Statistically significant
cyclic oscillations with periods of about 100, 122, 205, 350 and
1200 years have been revealed. About 200-year cycle, which was
unnoticeable in the relatively short 250-year series of the most
reliable instrumental data (since it was reduced by other long-period
oscillations), proved to be the most powerful among these oscil-lations.
An analysis of obtained results has indicated that it is highly probable
that the next long-period minimum of solar activity, which will possibly
be not so deep as the Maunder and Sperer minimums, will be formed in the
21st century.
International Journal of Geomagnetism and Aeronomy,v.43,No5,2003,pp
553-561
The full HTML version of this paper is here
THE SOLAR ACTIVITY DURING THE HOLOCENE: AMPLITUDE VARIATIONS OF
QUASY-CENTURY AND QUASY-TWO-CENTURY SOLAR CYCLES
Boris Komitov, Boncho Bonev, Kaloyan Penev and Stephano Sello
in Proceedings IAUS 223 'Multi-Wavelength Investigations of the
Solar Activity', eds. A. V. Stepanov, E. E. Benevolenskaya &
A. G. Kosovichev, Cambridge University Press, pp.705-706
Click here
SUN, CLIMATE AND THEIR CHANGES IN THE TIME
Boris Komitov
In this paper an comparison between the solar
activity variations and climate changes has been provided. The used
solar activity reconstructions are on the base of almost all main,
famous nowadays data series: a) instrumental observations of sunspot
activity during the last ~ 400 years; b) ground based and satellite
observations of solar EUV , radio and corpuscular fluxes , solar and
interplanetary magnetic field, solar wind and total solar irradiance
for the last few decades; c) historical records for auroras and simple
eye observations of sunspots (for the last 1700 years); d) “cosmogenic”
radioisothopes ( 14C and 10Be) measurements in
tree rings (for the last 10 000 years), continental ices ( the last
1200 years) and oceanic sediments probes (the last ~400 000 years) .
Four time-scales of the climate changes has been
used in this study: “geological” - for the last ~ 800 million years;
“prehistorical “ (1 and 2)- for the last ~130 000 years and ~23000
years respectively ; and “historical” scale – for the last 1200 years.
For the last three one the relationship ‘Sun-climate’ has been
discussed. The climatic changes in Bulgaria during the last century and
its relation to the solar activity has been to shortly described.
It is concluded that the Sun’s variability is the
main factor of the climatic changes during the last ~ 400 000 years .
The Earth orbit’s effects, described in Milankovich theory are
significant too in “prehistorical scale-1”, but most probably, they are
on the second place. All significant climatic extremums during the last
10 000 years are in coincidience with corresponding solar activity
extremums. The “global warming” effect in 20th century
corresponded with the most higher solar activity level during the last
~ 1000 years, and no antropogenic effect for the explanation of this
climatic phenomena is necessary to include .
An evidence that the main historical tendencies are modulated by
climatic changes and solar-climatic relationships is given. The last
one is discussed in the light of Arnold Toynbee’s “civillization
theory”.
( a paper printed in Nauka, 2005,No6) in Bulgarian
The full version of this paper in English is here
THE
SUPERCENTURIAL SOLAR MINIMA AND THEIR PRECEDING PHENOMENA
Boris Komitov
The main
aim of this study is to find different observational characteristics of
sunspot cycles, which could be used as precursors of forthcoming
supercenturial solar minima. A data set of indirect records for solar
activity (so called Schove’s series) between 214 BC - AD 2000 has been
analyzed. Two potential precursors of the further behaviour of the
solar activity have been pointed out – the violation of
Gnevyshev-Ohl’s rule in even-odd numbered pairs of Schwabe-Wolf’s
cycles and the temporary increasing of the cycles duration. A third
method for prediction, based on two-factor regression model has been
applied too. In this method the magnitudes of both even-odd sunspot
cycles are used as predictors. On the base of the actual data for the
current pair of the Zurich cycles No. 22 and 23 a prediction for a
relatively weak sunspot cycle No. 24 with expected maximum about AD
2013 and Wolf’s index Wmax ~ 90 was made. A prediction of forthcoming
supercenturial solar minimum in the period AD 2030–2080, like the
Dalton minimum in AD 1795-1830, is given also. Some climatic effects
may be expected in the period of the supercenturial solar minimum. As a
result a “global cooling” climatic effect in the range of 0.4- 07
C could be expected.
Bulg.Astron.Journal.,
2007,No 9
The full version of this paper in English is here
================================================================
THE “SUN - CLIMATE”
RELATIONSHIP : I. THE SUNSPOTS AND THE CLIMATE
Boris Komitov
This is the first one of a three
papers series, which concern the problem for the powerful subcenturial
and quasi-centurial (mainly 50-55 , 60-65 and ~120-130 yrs)
climatic oscilations origin. The 50-55 and 60-65 yrs cycles
are very clearly detectable in a large number of global as
well as regional climatic and climate –related parameters such as
the Northern hemisphere and World Ocean surface temperatures, regional
temperatures and tree rings width series, atmospheric CO2 density
etc. The abovesaided cycles havn’t clear analogs in
sunspot activity.
A detailed study
over diffrerent types of solar, geophysical and climatic indexes
(the Zurich (Ri) and Group Sunspot Numbers (GSN), the “Greenland”
and “Antarctic” 10Be , the middle latitude auroras + two global
and one regional climatic time series) has been provided.
An evidence that the subcenturial climatic oscilations in range
of 30-70 years (and inddeed the 120-130 yrs cycle too) are caused
by processes on the Sun (most probably in the corona ) has been found
as a final result (paper III).
The
subcenturial quasi-cyclic oscilations in Earth surface
temperatures as well as the “cosmogenic” berryllium time series
from Greenland ( AD 1423-1985) and Antarctica ( AD 850 – 1900) ice
probes are the object of the present papers. A 60-67 year
cycle has been found in the both to ones. It is very powerful in the
“greenland” 10Be series and relatively weaker, but statistical
significant in the “antarctic” one too. A good coincidience between the
extremums of 10Be and climatic indexes has been found. On other
hand there are weak statisticaly significant peaks near to ~60 years
both in Ri and GSN series too. The intermediate conclusion in
this paper (I) is that the sunspot and climatic data are not enough
strong basis to choice is the quasi 50-55 ,–60-65 year and 120-130 yrs
10Be cycles by solar or climatic origin. In the case if a solar
source of 10Be (and climate) subcenturial oscilations exist it should
not be in strong relationship with the overall sunspot activity indexes
such as Ri and GSN. Most probably this source could be “based” in
the corona.
Bulg.Astron.Journal.,
2009,No 11
The full version of this paper in English is
here
====================================================================
THE “SUN - CLIMATE”
RELATIONSHIP : II. THE “COSMOGENIC” BERRYLLIUM
AND THE MIDDLE LATITUDE AURORA
Boris Komitov
It has been already pointed out in the
our previous paper I that the subcenturial climate cycles
by durations in the range of 50- 70 years could be by solar
origin. As an argument for the last one the fact for the
existence of weak , but statistically
significant cycles traces of subcenturial range in the
sunspot Zurich and Group sunspot number series has been noted.
Additional evidences for the solar
origin of the subcenturial climate variations in this paper (II) are
suggested. Two indirect and independent each
other solar proxies has been studeid: A. The “cosmogenic” 10Be data
series (the both “Greenland” and “Antarctic” ones)
; B. The middle latitude aurora (MLA) events
for 18th and 19th centuries from a catalogue data which are
published in the National Geophysical Data Center of USA.
The most important results could
be summarized as: 1. There are strong quasi-50-55 ~65 and ~ 120
year oscilations in the “Greenlad” 10Be concentration data series. 2. A
relaatively weak , but stattistical significant ~60-65 year cycle
+ essentially powerest 130 year cycle in the “Antarcic” 10Be
series has been found too. 3. There is very
strong 62-63 year oscilation in the annual numbers of middle
latitude aurora. The last fact is a very strong evidence that a
cycle with the corresponding duration exist in the most powerful solar
activity phenomena ( flares and CME’s).
There is a relative good coincidience
berween the corresponding extremums of 60-yr cycles in 10Be and MLA
series. The last one is an indicator that most probably in
the epochs of 60 yr maximums of MLA a significant part of 10Be is
generated in the stratosphere by high energetic solar particles
in addition to the galactic cosmic rays (GCR) .
Bulg.Astron.Journal.,
2009,No 12
The full version of this paper in English is here
====================================================================
ABOUT A MECHANISM OF THE
SHORT PERIOD 160-MIN. RADIAL PULSATIONS OF SUN
Ivan T. Ivanov(1), Valentina T.
Taneva(2) and Boris Komitov(3)
(1) Department of Physics and
Biophysics, Medical Institute, Thracian University, 6000 Stara Zagora;
(2) Institute of Applied Physics,
Technical University of Sofia
(3) Bulgarian Academy of
Sciences - Institute of Astronomy, 6003, Stara Zagora-3, P.O. Box 39
b_komitov@sz.inetg.bg
The visible diameter of Sun oscilates with a period of 160 min. The
same type of periodicity is also found in a huge number of solar
radiation parameters. To elucidate the origin of these longitudinal
radial pulsations we have used the equation for the equilibrium of
inner layers which, after linearization, turned into the harmonic
oscilator equation. The latter equation allows radial pulsations whose
period and wave length were calculated using regresion expresions for
the gas presure and density in various layers. The radial pulsations
originate at the surface of active zone and propagate til the
litosphere, where they undergo full inner reflection producing
undersurface stationary waves with a period of 150-160 min.
Key words: Sun; 160 min radial pulsations; mechanical waves;
balance equation
e-print: arXiv:0912.1211
The full version of this paper in English is here
==================================================================
The "Sun–climate" relationship. III. Solar
eruptions, north-south
sunspot area asymmetry and Earth climate
Boris Komitov
Institute of Astronomy, Bulgarian
Academy of Sciences, 1784 Sofia, Bulgaria
b_komitov@sz.inetg.bg
(Research report. Accepted on
12.12.2009)
Abstract. In this Paper III, the last
one of the series, additional evidences are given that
the fluxes of solar high energy
particles, with energies higher than 100 MeV (the solar
cosmic rays), are a very important
component of the “Sun–climate" relationship (see also
Paper I and Psper II). It is known
that the total solar irradiance and the galactic cosmic
rays produce an integral climate
effect of cooling in sunspot minima epochs and warming in
sunspot maxima epochs. Contrariwise,
the powerful solar corpuscular events cause cooling
predominantly during the epochs of
their high levels. By this reason subcenturial global
and regional temperature quasi-cyclic
changes with duration of approximately 60 years
could be tracked during the last 150
years of instrumental climate observations. This paper
shows that this subcenturial
oscillation is very important in the group sunspot number data
series since the Maunder minimum up to
the end of 20th century. Only a relatively short
period, closely before and during the
last centurial Gleissberg-Gnevishev’s minimum (AD
1898-1923), when this cycle is totally
absent, is an exception there. Thus the solar eruptive
activity make the total "Sun–climate"
relationship essentially more complicated as it could
be expected if only the total solar
irradiance and the galactic cosmic rays variations are
taken into account. From this point of
view the climate warming tendency after AD 1975
has rather natural than anthropogenic
origin. It is also shown that the efficiency of the solar
corpuscular activity over the climate
strongly depends on the "north-south" asymmetry of
the solar activity centers (as a proxy
the sunspots area north-south asymmetry index A
is used there). The climate cooling
effect in the Northern hemisphere is most powerful
during the epochs of predominantly
positive values of A. This effect is very significant in
combination with high level of the
index of the group sunspot number. A strong quasi
120-130-year "hypercycle" has been
detected in the A index during the period of AD 1821-
1994. Most probably the observed
120-130-year cyclity in the climate and cosmogenic 10Be
continental ice core data (both
"Greenland" and "Antarctic" series) is related to this cycle.
In the end the expected climate
changes during the next decades and especially the new
solar sunspot cycle No 24 are
discussed on the base of the "multiple" nature of the "Sun–
climate" relationship.
Key words: Sun, sun-climate
relationship, sunspots, sunspot asymmetry
The full version of this paper in English is here
===========================================================================
About the use of a modified
brightness parameter for
photometric observations of comets
Boris Komitov, Vladimir Shkodrov
Institute of Astronomy, Bulgarian
Academy of Sciences
72 Tsarigradsko Shousse Blvd., 1784
Sofia, Bulgaria
bkomitov@sz.inetg.bg
(Research report. Accepted on
09.02.2010)
Abstract. The aim of this paper is to study the mathematical features
of a cometary
photometric parameter, which is called
by us a "modified intensity". It is defined as ǫ(l) =
E(l)l, where E(l) is the intensity of
a separated gas emission on a projective (pericentral)
distance l to the cometary nucleus.
The Haser’s model of the parent and daughter gas
molecules distribution is used. It is
pointed out that the parameter profile ǫ could be used
directly for a prompt analysis both of
the main generation mechanism of the observed
emission s, as well as of a rough
parent molecules scale length estimation in the range of
50% precision.
Key words: comets, cometary
photometry, parent molecules
The full version of this paper in English is here
==========================================================================
Determination of the sunspot minimum epoch between the cycles No 23
and 24 and prediction of the
cycle No 24 magnitude on the base of
the "Waldmeier’s Rule"
Boris Komitov, Peter Duchlev,
Konstantin Stoychev,
Momchil Dechev, Kostadinka Koleva
Institute of Astronomy and NAO,
Bulgarian Academy of Sciences, Sofia
b_komitov@sz.inetg.bg
(Research report. Accepted on
29.09.2010)
Abstract. The main purpose of this
study is determination of the solar minimum date
before the new sunspot cycle No 24.
The purpose is realized by using of four types of mean
daily data values for the period Jan
1, 2006 – Dec 31, 2009: 1) the solar radioindex F10.7;
2) the International sunspot number Ri
; 3) the total solar irradiance index (TSI), and
4) the daily number of X-ray flares of
classes from “B” to “X” by data of the soft X-ray
channel (0.1–0.8 nm) of the GOES
satellite. It is found that the mean starting moment of
the upward solar activity tendency
(the mean solar minimum) is Nov 6, 2008. So, the solar
cycle No 23 length is estimated to ~
12.6 years. A conclusion for a relatively weak general
magnitude of solar cycle No 24 is
made. Using a relationship based on the “Waldmeier’s
rule” a near maximal value of the
mean yearly sunspot number of Ri = 72
± 27 has been
determined for cycle No 24.
Key words: Sun, solar minimum, solar
cycle No 24
The full version of this paper in English is here
==========================================================================
THE SOLAR ELECTROMAGNETIC
RADIATION CHANGES DURING THE TRANSITION
EPOCH BETWEEN ZURICH CYCLES No 23 AND 24
Boris Komitov
Bulgarian Academy of Sciences-
Institute of Astronomy and NAO Rozhen;
b_komitov@sz.inetg.bg
ABSTRACT
The dynamics of solar
electromagnetic flux during the downward phase of sunspot cycle
No 23 (SC23) and the
upward phase of cycle No 24
(SC24) is analysed. For this aim the instrumental data series
of TIM
(Total Irradiance Monitor) and
SOLSTICE (The Solar Stellar Irradiance Comparison Experiment)
instruments on
the board of SORCE satellite during
the period March / May 2003 – February 2011 are used. The
study contain
analysis of variations of TSI, mid
UV-range (180-310 nm) flux and the “faculae” MgII –index. A
comparison with
the sunspot and flare activity is
made. The obtained results in the aspect of long term variations of
solar activity,
as well as to the ozone
and climate changes are discussed.
Bulgarian Astronomical Journal 2011 v.17. pp110-117
The full version of this paper in English is here
==================================================================================
THE STRATOSPHERIC
OZONE, SOLAR ACTIVITY AND VOLCANISM
Boris Komitov and
Konstantin Stoychev
Bulgarian Academy of Sciences –
Institute of Astronomy and National Astronomical Observatory “Rozhen”,
Bulgaria, Sofia; b_komitov@sz.inetg.bg
ABSTRACT
The aim of this study is to analyse
the long-term (multiannual) variations of the total ozone content (TOC)
on the base of TOMS instrument measurements on the board of Nimbus-7
satellite for the period 1979-1993 AD. The total effects of the solar
activity forcing over stratosphere ozone has been investigated by using
multiple regressional analysis. The monthly radio-index F10.7, the
cosmic rays neutron flux, the geomagnetic index Ap and the number of
GOES x-ray X-class flares have been used as solar or solar-modulated
parameters as predictors in the model. The global mean-monthly TOC
parameter has been used as a predictant.
It has been
found that the coefficient of correlation of the model between TOC and
above-mentioned solar and geomagnetic factors is about 0.544. Thus the
corresponding factor variance is about 37%. The results calculated by
the model have been removed from the original TOC data. It has been
found out that during the first 12 years since 1979 the downward trend
is predominantly caused by the solar and solar-modulated processes.
However during the remaining 3 years after 1990 the slope of the
negative trend has been essentially increased. This phenomenon could
only be explained by some catastrophic event. Most probably such one is
the Pinatubo eruption in June 1991. An evidence for the
possibility that the last one is caused by trigger – effect from the
extremally high solar flare activity in May-June 1991 is given.
Bulgarian Astronomical Journal 2011 v.17. pp118-125
The full version of this paper in English is here
==================================================================================
SOLAR RADIOBURSTS
OBSERVATIONS AT f= 29.9 MHz IN STARA ZAGORA, BULGARIA: FIRST
DATA, RESULTS AND ANALYSIS
Boris Komitov, Nikolai Marinov
ABSTRACT
In this paper a first testing series of radiobursts observations
at f= 29.9 MHz during the period
April 2009- March 2011 in Stara Zagora, Bulgaria, as well as their
analysis is discissed. The main interest is focused over the
observations on Feb. 15. 2011 –one of the most active days during
the upward phase of
solar cycle No 24.
Bulgarian Astronomical Journal
2011 v.17. pp126-132
The full version of this paper in English is here
==========================================================================
HELIOGEOTECTONICS
Boris Komitov
Abstract. The possible trigger mechanisms by solargeomagnetic origin
for excitation of part of terrestrial tektonics events (earthquackes
and volcanic erruptions) are subject of the present study. Evidences,
that some of the most significant tektonic events during last decades
are close correlated with solar eruptive processes and corresponding
geomagnetic storms, are given. The most powerful eruption in 20th
century of the Pinatubo volcano in 1991 as well as the catastrophic
Japan’s earthquacke in 2011, March 11 are considrered as examples. A
detailed analysis over the Pinatubo eruption, where the
solar-geomagnetic trigger effect even in the separated phases of
volcanic eruption is clear visible, has been provided. The possible
physical mechanisms for generation of solar- geomagnetic trigger
forcing over Earth tektonics are discussed too.
Keywords: Sol, Earth, tectonics, earthquakes, volkan.
Geosciences, 2011, No 2 (multimedia, in Russian)
Streaming video
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The long term solar activity
regarding to 24th Zurich cycle
B.Komitov and V. Kaftan
Abstract. In this paper an estimation of the present solar
activity state on the base of time series analysis of different
parameters is given. The longest presented there time series are data
for auroras, naked eye visible sunspots, earthquakes, extremely
meteorological events, annual tree ring widths, radioactive isotopes
contents in tree rings, speleological objects, corals, continental
ices, oceanic sediments etc. The main oscillations with periods close
to 100, 200, 350 and 1100 years has been established in these series.
The possibility of secondary long term solar activity minimum during
the current century is demonstrated and proved. The last one is
expected on the base of superposition of supercenturial oscillation
components as well as due to amplitude modulation of ~200 yr cycle by
the quasi- bimillenial (2200-2400 yr) solar Hallstadtzeit cycle. An
substantiated suggestion about involvement of the current solar
activity in the starting phase of a long periodic solar minimum, which
deepest phase should be expected during the second half of the present
century, is made. The moderate amplitudes of the previous and present
solar cycles are also an indication for the beginning of long periodic
solar activity decreasing.
Keywords: Solar activity, solar minimum, solar cycle
Geosciences, 2011, No 3-4 (multimedia, in English)
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