Showing papers by "Sallie L. Baliunas published in 2003"
TL;DR: A review of the early theories and models of solar eruptions can be found in this article, where the authors compare the advantages and disadvantages of different theories by discussing their advantages as well as pointing out important aspects that need improvement.
202 citations
TL;DR: In this article, the authors reviewed the 1000 yr climatic and environmental history of the Earth contained in various proxy records and concluded that the 20th century is probably not the warmest nor a uniquely extreme climatic period of the last millennium.
Abstract: The 1000 yr climatic and environmental history of the Earth contained in various proxy records is reviewed. As indicators, the proxies duly represent local climate. Because each is of a different nature, the results from the proxy indicators cannot be combined into a hemispheric or global quantitative composite. However, considered as an ensemble of individual expert opinions, the assemblage of local representations of climate establishes both the Little Ice Age and Medieval Warm Period as climatic anomalies with worldwide imprints, extending earlier results by Bryson et al. (1963), Lamb (1965), and numerous intervening research efforts. Furthermore, the individual proxies can be used to address the question of whether the 20th century is the warmest of the 2nd millennium locally. Across the world, many records reveal that the 20th century is probably not the warmest nor a uniquely extreme climatic period of the last millennium.
164 citations
TL;DR: In this paper, the authors examined the 1000-year climatic and environmental history of the Earth contained in various proxy records and examined the relevance and validity of the locality paradigm for climatological research, as studies of climatic changes on timescales of 50-100 years or longer are pursued.
Abstract: The 1000-year climatic and environmental history of the Earth contained in various proxy records is examined. As indicators, the proxies duly represent or record aspects of local climate. Questions on the relevance and validity of the locality paradigm for climatological research become sharper as studies of climatic changes on timescales of 50–100 years or longer are pursued. This is because thermal and dynamical constraints imposed by local geography become increasingly important as the air-sea-land interaction and coupling timescales increase. Because the nature of the various proxy climate indicators are so different, the results cannot be combined into a simple hemispheric or global quantitative composite. However, considered as an ensemble of individual observations, an assemblage of the local representations of climate establishes the reality of both the Little Ice Age and the Medieval Warm Period as climatic anomalies with world-wide imprints, extending earlier results by Bryson et al. (1963), Lam...
101 citations
TL;DR: In this article, the authors investigated a four-and-one-half year time-series of ROSAT HRI pointed observations of 61 Cygni A and B and compared the X-ray light curves with the chromospheric Ca-HK variability.
Abstract: We investigate a four-and-one-half year time-series of ROSAT HRI pointed observations of 61 Cyg A and B and compare the X-ray light curves with the chromospheric Ca HK variability. The ROSAT sampling rate was two pointings per year and typical errors lie in the range of 5–10%. The chromospheric cycles are well-known for both stars from the Mt. Wilson Ca HK survey. Although the time basis of our ROSAT observations is shorter than the 7-and 12-year cycles of components A and B, respectively, we find the long-term trend of coronal activity in close correlation with the chromospheric activity during the observation period, between 1993 and 1998. The chromospheric activity increased through maximum activity down to a minimum for component A, and from maximum to minimum activity for component B. The same behaviour is observed for the X-ray light curves but with much higher amplitudes by factors 2.5–3. The remaining scatter observed around low-order regression curves of coronal activity is small. We conclude that both stars do show coronal cycles and that coronal cycles are the dominant source of variability for 61 Cygni.
27 citations
TL;DR: In this article, high-resolution multispectral images of main-belt asteroid 3 Juno were taken at visible and near-IR wavelengths with the 100-inch telescope at Mount Wilson Observatory equipped with an adaptive optics system.
12 citations
TL;DR: Soon and Baliunas as mentioned in this paper pointed out that studies of climate and environmental changes (including temperature) on hemispheric or global scales over time periods of millennia based on paleoclimate proxies must contend with significant uncertainties.
Abstract: We write in response to the Forum article by Mann et al. (Eos, 8 July 2003;“M03”), noting first two points of apparent agreement with our work [Soon and Baliunas, 2003; Soon et al., 2003;“SB03”]:
(1) Studies of climatic and environmental changes (including temperature) on hemispheric or global scales over time periods of millennia based on paleoclimate proxies must contend with significant uncertainties.
8 citations
28 Nov 2003
TL;DR: In this article, the solar activity cycle is examined, taking into account the sunspot cycle, and solar dynamo models are considered along with long-term activity fluctuations of cool stars.
Abstract: The variety of stellar chromospheric and coronal activity provides a framework for understanding solar and stellar magnetic activity. It is pointed out that the recognition of an 11-yr periodicity within the record of sunspot numbers is a relatively recent discovery of just over a century ago. The solar activity cycle is examined, taking into account the sunspot cycle, and solar dynamo models. Time-averaged stellar chromospheric activity levels are considered along with long-term activity fluctuations of cool stars. Attention is given to the direct measurement of stellar magnetic fields, solar luminosity variations, the RS Canum Venaticorum and BY Draconis variables, continuum variations in lower main sequence stars, chromospheric variations in lower main sequence stars, and chromospheric variations in evolved stars.
2 citations