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Solar Variability (solar + variability)

Distribution by Scientific Domains
Humanities and Social Sciences66%

Selected Abstracts

CLIMATE FORCINGS AND THEIR INFLUENCE ON ALPINE HISTORY AS RECONSTRUCTED THROUGH THE APPLICATION OF SYNCHROTRON-BASED X-RAY MICROFLUORESCENCE ON LAYERED STALAGMITES*

ARCHAEOMETRY, Issue 2 2005
S. FRISIA
Solar variability and volcanic activity strongly interact with climate and the environment. Synchrotron radiation X-ray microfluorescence (micro-XRF) to an annually laminated Alpine stalagmite confirmed that annual laminae result from hydrological variability and changes in the duration of soil microbial degradation. The latter is modulated by solar variability. At the centennial timescale, growth rate and solar activity appear to be correlated with temperature change, with low temperatures at solar minima. By combining micro-XRF and absorption spectroscopy techniques (XANES), we also found that speleothems are a new archive of aerosol sulphate related to volcanic activity. Peaks in S-concentration from c. 5.2 to 5.0 ka bp in an Alpine stalagmite suggest that multiple volcanic sulphate aerosol emissions enhanced Mid-Holocene summer cooling, thus favouring the preservation of the Alpine Iceman mummy in a persistent ice casket. [source]

Transient climate simulation forced by natural and anthropogenic climate forcings

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 6 2002
Cédric Bertrand
Abstract Numerical experiments have been carried out with a two-dimensional sector-averaged global climate model coupled to a diffusive ocean in order to assess the potential impact of four hypothesized mechanisms of decadal to century-scale climate variability, both natural and anthropogenically induced: (1) solar variability; (2) variability in volcanic aerosol loading of the atmosphere; (3) anthropogenic increase of sulphate aerosols' concentration; (4) anthropogenic increase of greenhouse gas concentrations. Our results suggest that neither the individual responses nor the combined natural or anthropogenic forcings allow one to reproduce all of the recorded major temperature fluctuations since the latter half of the 19th century. They show that these temperature variations are the result of both naturally driven climate fluctuations and the effects of industrialization. By contrast, the dominant cause of decade-to-century-scale variability of the 21st century is likely to be changes in atmospheric trace-gas concentrations. Indeed, when the solar, volcanic, and tropospheric aerosols forcings used in our experiments are extended into the future, they are unable to counter the expected greenhouse warming. Copyright © 2002 Royal Meteorological Society. [source]

Climatic change during the last 4000 years in the southern Tarim Basin, Xinjiang, northwest China,

JOURNAL OF QUATERNARY SCIENCE, Issue 7 2007
Wei Zhong
Abstract In this study, a ca. 4000,cal. yr ancient lacustrine (or wetland) sediment record at the southern margin of Tarim Basin is used to reconstruct the history of climate change. Six radiocarbon dates on organic matter were obtained. ,18O and ,13C of carbonate, pollen and sediment particle size were analysed for climate proxies. The proxies indicate that a drier climate prevailed in the area before ca. 1010 BC and during period 1010 BC,AD 500 climate then changed rapidly and continuously from dry to moist, but after about AD 500 climate generally shows dry condition. Several centennial-scale climatic events were revealed, with the wettest spell during AD 450,550, and a relatively wetter interval between AD 930,1030. Pollen results show that regional climate may influence human agricultural activities. Spectral analysis of mean grain size (MGS) proxy reveals statistically pronounced cyclic signals, such as ca. 200,yr, ca. 120,yr, ca. 90,yr, ca. 45,yr and ca. 33 or 30,yr, which may be associated with solar activities, implying that solar variability plays an important role in the decadal- and centennial-scale climate variations in the study area. Copyright © 2007 John Wiley & Sons, Ltd. [source]

A multiproxy climate record from a raised bog in County Fermanagh, Northern Ireland: a critical examination of the link between bog surface wetness and solar variability,

JOURNAL OF QUATERNARY SCIENCE, Issue 7 2007
Graeme T. Swindles
Abstract A proxy climate record from a raised bog in County Fermanagh, Northern Ireland, is presented. The record spans the interval between 2850,cal.,yr,BC and cal. yr AD 1000 and chronological control is achieved through the use of tephrochronology and 14C dating, including a wiggle-match on one section of the record. Palaeoclimatic inferences are based on a combination of a testate amoebae-derived water table reconstruction, peat humification and plant macrofossil analyses. This multiproxy approach enables proxy-specific effects to be identified. Major wet shifts are registered in the proxies at ca. 1510,cal.,yr,BC, 750,cal.,yr,BC and cal. yr AD 470. Smaller magnitude shifts to wetter conditions are also recorded at ca. 380,cal.,yr,BC, 150,cal.,yr,BC, cal. yr AD 180, and cal. yr AD 690. It is hypothesised that the wet shifts are not merely local events as they appear to be linked to wider climate deteriorations in northwest Europe. Harmonic analysis of the proxies illustrates statistically significant periodicities of 580, 423,373, 307 and 265 years that may be related to wider Holocene climate cycles. This paper illustrates how the timing of climate changes registered in peat profiles records can be precisely constrained using tephrochronology to examine possible climatic responses to solar forcing. Relying on interpolated chronologies with considerable dating uncertainty must be avoided if the climatic responses to forcing mechanisms are to be fully understood. Copyright © 2007 John Wiley & Sons, Ltd. [source]

CLIMATE FORCINGS AND THEIR INFLUENCE ON ALPINE HISTORY AS RECONSTRUCTED THROUGH THE APPLICATION OF SYNCHROTRON-BASED X-RAY MICROFLUORESCENCE ON LAYERED STALAGMITES*

ARCHAEOMETRY, Issue 2 2005
S. FRISIA
Solar variability and volcanic activity strongly interact with climate and the environment. Synchrotron radiation X-ray microfluorescence (micro-XRF) to an annually laminated Alpine stalagmite confirmed that annual laminae result from hydrological variability and changes in the duration of soil microbial degradation. The latter is modulated by solar variability. At the centennial timescale, growth rate and solar activity appear to be correlated with temperature change, with low temperatures at solar minima. By combining micro-XRF and absorption spectroscopy techniques (XANES), we also found that speleothems are a new archive of aerosol sulphate related to volcanic activity. Peaks in S-concentration from c. 5.2 to 5.0 ka bp in an Alpine stalagmite suggest that multiple volcanic sulphate aerosol emissions enhanced Mid-Holocene summer cooling, thus favouring the preservation of the Alpine Iceman mummy in a persistent ice casket. [source]

Advanced Technology Solar Telescope: A status report

ASTRONOMISCHE NACHRICHTEN, Issue 6 2010
S.L. Keil
Abstract Magnetic fields control the inconstant Sun. The key to understanding solar variability and its direct impact on the Earth rests with understanding all aspects of these magnetic fields. The Advanced Technology Solar Telescope (ATST) has been design specifically for magnetic remote sensing. Its collecting area, spatial resolution, scattered light, polarization properties, and wavelength performance all insure ATST will be able to observe magnetic fields at all heights in the solar atmosphere from photosphere to corona. After several years of design efforts, ATST has been approved by the U.S. National Science Foundation to begin construction with a not to exceed cost cap of approximately $298M. Work packages for major telescope components will be released for bid over the next several months. An application for a building permit has been submitted (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]