bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lower and middle atmosphere and ozone layer responses to solar variation
Authors: Elias Ana G. 
Published: February 2010

AbstractGlobal warming in the troposphere and the decrease of stratospheric ozone concentration has become a major concern to the scientific community. The increase in greenhouse gases and aerosols concentration is believed to be the main cause of this global change in the lower atmosphere and in stratospheric ozone, which is corresponded by a cooling in the middle and upper atmosphere. However, there are natural sources, such as the sun and volcanic eruptions, with the same ability to produce global changes in the atmosphere. The present work will focus on solar variation and its signature in lower and middle atmosphere parameters. The Sun can influence the Earth and its climate through electromagnetic radiation variations and also through changes in the solar wind which causes geomagnetic storms. The effects of both mechanisms over the lower and middle atmosphere and ozone layer will be discussed through an overview of selected papers, which by no means cover this subject that is extremely wide and complex. A fundamental understanding of the atmosphere response to solar variations is required for understanding and interpreting the causes of atmospheric variability. This is an essential focus of climate science, which is seeking to determine the extent to which human activities are altering the planetary energy balance through the emission of greenhouse gases and pollutants.
Possible traces of solar activity effect on the surface air temperature of mid-latitudes
Authors: Kilcik Ali , Özgüç Atila , Rozelot Jean-Pierre 
Published: February 2010

AbstractIn this study we investigate the effects of solar activity on the surface air temperature of mid-latitudes. This enables us to understand existence of solar activity effects on the temperature. We used surface air temperature and pressure data as climate parameters, and solar flare index data as solar activity indicator, for the 25 - 50 degree longitude and 30 - 70 degree latitude zone, including Turkey and European part of Russia. We considered the parameters temperature, pressure and flare index data for the period ranging from January 1975 to the end of December 2007, which covers almost three solar cycles, namely 21st, 22nd, and 23rd. We found some significant correlations between solar activity and surface air temperature for cycles 22 and 23 for some zones. We applied multitaper method to obtain the cyclic behavior of surface air temperature data sets. The most pronounced power peaks were found by this transform around 1.2 and 2.5 years which were reported earlier for some solar activity indicators. We concluded that signature of solar activity effect exists on surface air temperature of mid-latitudes where we studied.
Influence of the solar radiation on Earth's climate using the LMDz-REPROBUS model
Authors: Lefebvre Sandrine , Marchand Marion , Bekki Slimane , Keckhut Philippe , Lefèvre Franck , Claud Chantal , Cugnet David , Thuillier Gérard , Hauchecorne Alain 
Published: February 2010

AbstractThe atmospheric response to the 11-year solar cycle is studied using the fully interactive 3-D coupled chemistry-general circulation model LMDz-REPROBUS with a complete seasonal cycle. We will show results concerning a comparison between two series of 20-year runs, one in maximum of activity and the other in minimum. The stratosphere-troposphere system shows partly significant response to a solar cycle enhancement of UV radiation. We show how the changes in stratospheric ozone, temperature and zonal wind are connected.
Solar cycle changes of large-scale solar wind structure
Authors: Manoharan P. K. 
Published: February 2010

AbstractIn this paper, I present the results on large-scale evolution of density turbulence of solar wind in the inner heliosphere during 1985–2009. At a given distance from the Sun, the density turbulence is maximum around the maximum phase of the solar cycle and it reduces to ~70%, near the minimum phase. However, in the current minimum of solar activity, the level of turbulence has gradually decreased, starting from the year 2005, to the present level of ~30%. These results suggest that the source of solar wind changes globally, with the important implication that the supply of mass and energy from the Sun to the interplanetary space has significantly reduced in the present low level of activity.
Observation of non-Gaussianity and phase synchronization in intermittent magnetic field turbulence in the solar-terrestrial environment
Authors: Miranda Rodrigo A. , Chian Abraham C.-L. , Dasso Sergio , Echer Ezequiel , Muñoz Pablo R. , Trivedi Nalin B. , Tsurutani Bruce T. , Yamada Michio 
Published: February 2010

AbstractWe apply two nonlinear techniques, kurtosis and phase coherence index, to analyze magnetic field measurements from SOHO MDI solar images, ACE and Cluster data in the solar wind, and ground magnetometers in Brazil. We focus on two events: a non-ICME event in February 2002 and an ICME event in January 2005. Finite degree of non-Gaussianity and phase synchronization are observed in all datasets. The nonlinear response of the Earth's geomagnetic field to an ICME event in the solar wind is discussed.
Observation of magnetic reconnection and current sheets in the solar wind
Authors: Muñoz Pablo R. , Chian Abraham C.-L. , Miranda Rodrigo A. , Yamada Michio 
Published: February 2010

AbstractWe apply single- and multi-spacecraft techniques to search for currents sheets in the solar wind during the ICME event of 21 January 2005, using the Cluster magnetic field data. Two large-scale currents sheets are detected at the leading boundary of the ICME ejecta using the single-spacecraft technique, which exhibit physical characteristics typical of magnetic reconnection exhausts in the solar wind.
Magnetic activity, high-energy radiation and variability: from young solar analogs to low-mass objects
Authors: Güdel Manuel 
Published: February 2010

AbstractMagnetic activity on cool stars expresses itself in a bewildering variety of radiative and particle output originating from magnetic regions between the photosphere and the corona. Given its origin in evolving magnetic fields, most of this output is variable in time. Radiation in the ultraviolet, the extreme ultraviolet, and the X-ray ranges are important for heating and ionizing upper planetary atmospheres and thus driving atmospheric evaporation. Additionally, stellar winds interact with the upper atmospheres and may lead to further erosion. The stellar high-energy output is therefore a prime factor in determining habitability of planets. We summarize our knowledge of magnetic activity in young solar analogs and lower-mass stars and show how the stellar output changes on evolutionary timescales.
Impact of the solar magnetic cycle on a protoplanetary disk
Authors: Tlatov Andrey G. 
Published: February 2010

AbstractWe consider the influence of the periodic magnetic field of the Sun on the protoplanetary disk. Solar magnetic cycle may create a special orbit, which were formed main planets of the solar system. In orbits on which magnetic field accumulation occurs most effectively, there is a substance replacement. The Keplerian orbit with the period close to the period of solar magnetic cycle T ~ TM is most unstable for material accumulation. Two most close orbits where there is an accumulation of substance have periods T = 1/2TM and T=5/4TM. These orbits on are close to orbits of Jupiter and Saturn. Other planets were probably formed under influence of gravitation of Jupiter, Saturn and solar magnetic cycle. Perhaps, the effect of periodic magnetic field can explain the Titius-Bode rule.
Solar-terrestrial energy transfer during sunspot cycles and mechanism of Earth rotation excitation
Authors: Chapanov Yavor , Gambis Daniel 
Published: February 2010

AbstractThe solar-terrestrial energy transfer, due to the total solar irradiance (TSI), solar wind and interplanetary magnetic field, has 11-year modulation during the sunspot cycles. Other oscillations of solar-terrestrial energy transfer are with periods of 22 and 45 year due to the magnetic reversal and equatorial solar asymmetry, which cause corresponding oscillations of all Earth systems, including climate and weather, atmosphere and ocean circulations, geomagnetic field and core processes. A part of this energy variation is transformed to oscillations of the Earth rotation. A model of indirect mechanism of Earth rotation excitation during sunspot cycles is proposed, which is based on global water circulation and periodical mass transfer between oceans and polar ice caps. The oscillations of the mean sea level (MSL) with periods 11, 22 and 45 years are determined by sea level data for the last two centuries from 13 maregraph stations. The necessary energy of water evaporation, corresponding to the observed MSL variations is provided by TSI oscillations with amplitudes between 0.2-0.5W/m2, determined by means of reconstructed time series of the TSI since 1610. The determined mean Universal Time (UT1) amplitudes, corresponding to the 22-year and 45-year cycles of the solar activity are 185ms and 310ms.
Common 22-year cycles of Earth rotation and solar activity
Authors: Chapanov Yavor , Vondrák Jan , Ron Cyril 
Published: February 2010

AbstractThe 22-year oscillations of the Earth rotation due to several geophysical processes in the core-mantle system, oceans, atmosphere and geomagnetic field are excited mainly by 22-year cycles of the solar activity. These geophysical processes produce their own oscillations of the Earth rotation with different periods around 22 years. The direct and indirect influence of the solar activity on 22-year cycles of the Earth rotation are separated from the core effects and corresponding amplitudes are estimated by means of two approaches. The first, direct approach uses extended time series of Wolf's numbers with 22-year cycles, determined by sign alternation of even sunspot cycles. A linear regression between 22-year cycles of UT1 and solar activity is determined and this regression model is used to calculate the UT1 response to the 22-year cycles of the solar activity. The second, indirect approach uses 22-year oscillation of the mean sea level, caused by water evaporation due to variations of the total solar irradiance. The influence of the mean sea level variations on the Earth rotation is calculated by means of an empirical model of global water redistribution. The core-mantle effects on the 22-year UT1 variations are determined by excluding the UT1 response to the solar activity and core angular momentum due to the geomagnetic field variations, according to the solutions from the Special Bureau of the Core (SBC).
Polarimetic search for exoplanets with a tangential transit
Authors: Ksanfomality L. V. 
Published: February 2010

AbstractThis paper is devoted to the data obtained in measurements of the linear light polarization of few stars (that are definitely known to possess planets) and the results of the measurements processing. One may surmise with caution that the suggested method yields positive results and, if confirmed, can be of use both in searching for exoplanets in transiting or tangentially transiting orbits and in refining their masses.
Influence of the Schwabe/Hale solar cycles on climate change during the Maunder Minimum
Authors: Miyahara Hiroko , Yokoyama Yusuke , Yamaguchi Yasuhiko T. 
Published: February 2010

AbstractWe have examined the variation of carbon-14 content in annual tree rings, and investigated the transitions of the characteristics of the Schwabe/Hale (11-year/22-year) solar and cosmic-ray cycles during the last 1200 years, focusing mainly on the Maunder and Spoerer minima and the early Medieval Maximum Period. It has been revealed that the mean length of the Schwabe/Hale cycles changes associated with the centennial-scale variation of solar activity level. The mean length of Schwabe cycle had been ~14 years during the Maunder Minimum, while it was ~9 years during the early Medieval Maximum Period. We have also found that climate proxy record shows cyclic variations similar to stretching/shortening Schwabe/Hale solar cycles in time, suggesting that both Schwabe and Hale solar cycles are playing important role in climate change. In this paper, we review the nature of Schwabe and Hale cycles of solar activity and cosmic-ray flux during the Maunder Minimum and their possible influence on climate change. We suggest that the Hale cycle of cosmic rays are amplified during the grand solar minima and thus the influence of cosmic rays on climate change is prominently recognizable during such periods.
STRESS – STEREO TRansiting Exoplanet and Stellar Survey
Authors: Sangaralingam Vinothini , Stevens Ian R. , Spreckley Steve , Debosscher Jonas 
Published: February 2010

AbstractThe Heliospheric Imager (HI) instruments on board the two STEREO (Solar TErrestrial RElations Observatory) spacecraft provides an excellent opportunity for space based stellar photometry. The HI instruments provide a wide area coverage (20° × 20° for the two HI-1 instruments and 70° × 70° for the two HI-2 instruments) and long continuous periods of observations (20 days and 70 days respectively). Using HI-1A which has a pass band of 6500Å to 7500Å and a cadence of 40 minutes, we have gathered photometric information for more than a million stars brighter than 12th magnitude for a period of two years. Here we present some early results from this study on a range of variable stars and the future prospects for the data.
The influence of starspots activity on the determination of planetary transit parameters
Authors: Silva-Válio Adriana 
Published: February 2010

AbstractAs a planet eclipses its parent star, dark spots on the surface of the star may be occulted, causing a detectable variation in the transit light curve. There are basically two effects caused by the presence of spots on the surface of the star which can alter the shape of the light curve during transits and thus preclude the correct determination of the planet physical and orbital parameters. The first one is that the presence of many spots within the latitude band occulted by the planet will cause the depth of the transit in the light curve to be shallower. This will erroneously result in a smaller radius for the planet. The other effect is that generated by spots located close to the limb of the star. In this case, the spots will interfere in the light curve during the times of ingress or egress of the planet, causing a decrease in the transit duration. This in turn will provide a larger value for the semi-major axis of the planetary orbit. Qualitative estimates of both effects are discussed and an example provided for a very active star, such as CoRoTo-2.
Evidence for climate variations induced by the 11-year solar and cosmic rays cycles
Authors: Bruckman William , Ramos Elio 
Published: February 2010

AbstractWe analyzed data from PSMSL monthly mean sea level seeking correlations between sea level fluctuations and the solar and cosmic rays 11 year cycle. The data reveals decadal variability that could be causally connected to the solar and cosmic rays cycle, since these periodic changes are correlated. It is also found that the solar (cosmic rays) cycle correlates (anti-correlates) with the mean global surface temperature anomaly. A probable explanation of the above correlations is that the solar intensity and cosmic rays variations induce oscillations in the average temperature and precipitation, with corresponding changes in the continental water and snow accumulation. Thus, for instance, a higher than average snow and water over land, and lower temperatures produce oceans thermal contraction and lower mass, implicating lower mean sea level.
Manifestation of the Jupiter's synodic period in the solar wind, interplanetary magnetic field and geophysical parameters
Authors: Samsonov S. N. , Skryabin N. G. 
Published: February 2010

AbstractStudying by the authors of paper of solar wind parameters, namely: density, speed and temperature and also a module of interplanetary magnetic field (IMF) intensity has allowed to find out in them fluctuations with the period of 399 days. From references it is known that this period coincidence with the synodic period of Jupiter. So long as close by the given period another source of such fluctuations is not known we have assumed that fluctuations with the period of 399 days are fluctuations with the synodic period of Jupiter. The change of the solar wind plasma parameters and IMF intensity can lead to the change of the Earth's magnetic field parameters and, as a consequence, to the change of charged particle fluxes in the Earth's magnetosphere. On this assumption the IMF intensity in the Earth's vicinity, geomagnetic disturbance (Kp-index) and riometer absorption for the years of 1986-1996 have been analyzed. The analysis of the data has shown the presence of certain changes of these physical parameters with the period of 399 days. When the Earth and Jupiter were found to be on the same magnetic field line, the IMF intensity was decreasing up to 3.0±0.57, the geomagnetic activity and riometer absorption were decreasing up to 5.2±1.46% and 9.4±2.63%, respectively.
Space solar missions
Authors: Vial Jean-Claude 
Published: February 2010

AbstractIn the frame of Symposium 264 which concerns Solar and Stellar Variability we address the space solar missions devoted to the various aspects of solar activity. We describe them in three time categories: missions ready for launch, missions which will operate in the 2012-2015 time frame and ambitious missions to be launched after 2015. We focus on the contributions of these missions according to the following criteria: Understanding mechanisms of activity, Improving detection and characterisation, Working out some prediction. Major activity contributors and manifestations are addressed: Coronal Mass Ejections, Flares, Solar winds, Magnetism (including dynamo), Irradiance.
First thoughts on stellar variability from Kepler commissioning data
Authors: Walkowicz Lucianne M. , Basri Gibor 
Published: February 2010

AbstractThe Kepler mission will obtain high precision, continuous lightcurves for more than ~150,000 stars over the next four years. Prior to primary mission operations, ten days of commissioning data were obtained for the ~52,000 brightest targets in the Kepler field. While Kepler's main goal is the discovery of transiting low mass planets, it will also provide a rich dataset for studies of variable stars. These commissioning data give a first glimpse of the amazing diversity of stellar variability Kepler will observe. Here, we discuss the tools we are currently developing to quantify variability in the Kepler data, and show initial results on the distribution of target stars in these metrics. Ultimately these measures will be used both to characterize the data and to select active rotationally modulated stars for rotation period determination.
X-exoplanets: an X-ray and EUV database for exoplanets
Authors: Sanz-Forcada J. , García-Álvarez D. , Velasco A. , Solano E. , Ribas I. , Micela G. , Pollock A. 
Published: February 2010

AbstractExtreme Ultraviolet (EUV) and X-ray emission is of great importance in several phenomena related to the formation of planetary systems and the atmospheres of planets. The atmospheric composition, and the mass of an exoplanet, are partly dependent on the X-ray and EUV radiation received during the first stages of formation and even during main sequence of the star. Biological life developing on exoplanets would depend severely on the high energy radiation arriving from its parent star.Here we present a database of the X-ray and EUV emission of all the stars currently known to host exoplanets. The archive is public and accessible through the Spanish Virtual Observatory (SVO). The database gives the user the option to download observed X-rays and EUV spectra. Synthetic spectra covering the spectral range 1–912 Å are also available (present day telescopes do not give access to the EUV range at λ > 180 Å). These spectra are created using coronal models after fitting observed spectra.
The development of the Heliometer of the Observatório Nacional
Authors: d'Ávila Victor , Reis Eugênio , Penna Jucira , Oliveira Luiz Carlos , Coletti Alissandro , Matias Victor , Andrei Alexandre , Boscardin Sergio 
Published: February 2010

AbstractThe Observatório Nacional at Rio de Janeiro has developed a new heliometer to perform accurate measurements of the solar diameter. The equipment makes use of split parabolic mirrors, rather than split achromatic lenses as objective. In its first campaign this reflector heliometer generated a few thousands of images of the Sun through which we evaluate the precision of the solar diameter measurements as been 5 mas. The mechanical and thermal stability of the instrument is guaranteed by the use of a telescope tube manufactured in carbon fiber. The tube firmly holds the heliometric mirrors and the CCD camera that collects the images. The perfect lodging between the two half-mirrors over its supporting plate defines the angular instrumental separation between the two images of the sun. The heliometric mirrors and supporting plate have been made in ceramic material in order to ensure the stability of the optical configuration and to maintain the two images of the solar disk displaced by a fixed angle in relation to each other. To verify the stability of the instrument we designed the procedures of collimation and comparison. The collimation consists of using the heliometer for measuring the diameter of an artificial solar image specifically created for this purpose. The comparison is performed by measuring the residual unfold of a punctual image after been unfold by two opposed heliometers. The heliometric approach allows the measurement of the solar diameter at any heliolatitude and can be undertaken as often as desired. Computer programs have been developed for automated image acquisition and analysis. The optical and mechanical design has been performed by using 3D computer aided design software.
Brazilian Decimetric Array (BDA) project - Phase II
Authors: Faria C. , Stephany S. , Sawant H. S. , Cecatto J. R. , Fernandes F. C. R. 
Published: February 2010

AbstractThe configuration of the second phase of the Brazilian Decimetric Array (BDA), installed at Cachoeira Paulista, Brazil (Longitude 45° 0′ 20″ W and Latitude 22° 41′ 19″ S), is a T-shaped array where 21 antennas are being added to existing 5 antennas of the first phase. In the third phase, in each arm of the T array, four more antennas will be added and baselines will be increased to 2.5 × 1.25 km in east-west and south directions, respectively. The antennas will be equally spaced at the distances of 250 meters from the central antenna of the T-array. Also, the frequency range will be increased to 1.2–1.7, 2.8 and 5.6 GHz. The Second phase of the BDA should be operational by the middle of 2010 and will operate in the frequency range of (1.2–1.7) GHz for solar and non solar observations. Here, we present the characteristics of the second phase of the BDA project, details of the array configuration, the u-v coverage, the synthesized beam obtained for the proposed configuration.