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Topic: Solar variation

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In the News (Sun 21 Apr 19)

  Solar Activity and Climate
Solar ultra-violet, visible and heat radiation are the primary factors for the Earth's climate, including global average temperatures, and these energy sources appear to be quite constant.
Whereas the solar influence is obvious in the data from the last four centuries, signatures of human activity are not yet distinguishable in the observations.
The observed long-term variation in solar energy output by means of the solar wind suggests that similar long-term changes in other manifestations of solar energy output may have occurred.
www.tmgnow.com /repository/solar/lassen1.html   (3115 words)

 Solar variation - Wikipedia, the free encyclopedia
Solar variations are fluctuations in the amount of energy emitted by the Sun.
A decrease in solar activity increases the GCR penetration of the troposphere and stratosphere.
In addition to variations in solar activity, the long term trends in Carbon-14 production are influenced by changes in the Earth's geomagnetic field and by changes in carbon cycling within the biosphere (particularly those associated with changes in the extent of vegetation since the last ice age).
en.wikipedia.org /wiki/Solar_variation   (4822 words)

 Big Bear Solar Observatory - Chromospheric Height Paper
The height of the solar chromosphere, as defined either by the height of the H-alpha band or the gradient of the flash spectrum in optical or radio wavelengths, has been of interest for many years.
All the data shown have been corrected for the solar P-angle and the position angles shown are thus zero at the actual solar north pole with increasing angles eastward from this.
The rms scatter of the small-scale variations is typically 500 Km for the e-fold measure and 1000 Km for the slope measure.
www.bbso.njit.edu /Research/chromosphere_paper.html   (6828 words)

 Changing Sun, Changing Climate   (Site not responding. Last check: 2007-10-12)
Sunspot variations, he declared, were "the only possible single factor of climatic control which might be made to account for all of these variations." Others thought they detected sunspot cycle correlations in the advance and retreat of mountain glaciers.
People continued to report weather features that varied with the sunspot cycle of 11 years, or with the full solar magnetic cycle of 22 years (the magnetic polarity of sunspots reverses from one 11-year cycle to the next).
However, if the output could vary a tenth of a percent or so over a single sunspot cycle, it was plausible to imagine that larger, longer-lasting changes could have come during the Maunder Minimum and other major solar variations.
www.aip.org /history/climate/solar.htm   (7340 words)

 Solar Irradiance and Long-Term Climate Variability
The horizontal dashed line shows the approximate variation that was directly measured in the sun's total irradiance (long known as the solar ``constant'') over the 11-year period encompassing the maxima of solar cycles 21 and 22, using the accepted numerical reference system.
The total irradiance variations seen to date have been tentatively explained in terms of a combination of decreases due to sunspot blocking and increases due to bright faculae and plages [Foukal and Lean, 1990], both of which are positively correlated with solar magnetic activity.
Using a simple one-dimensional model of the ocean's thermal structure, he calculated that variations in solar irradiance of several tenths of a percent on the time scale of decades to centuries would be needed to explain the effect, assuming that no other causes of temperature change were in operation.
www.agu.org /revgeophys/reid00/node2.html   (1525 words)

 Solar variation (via CobWeb/3.1 planetlab2.cs.unc.edu)   (Site not responding. Last check: 2007-10-12)
The variation is small (of the order of 1 W/square meter or 0.1 percent of the total) and was only established once satellite measurements of solar variation became available in the 1980s.
The quiet period observed from 1645 to 1710 is known as the Maunder Minimum and is associated with a near zero aundance of sunspots.
Because the flux of such cosmic rays is affected by the intensity of the interplanetary magnetic field carried by the solar wind, the rate at which Beryllium-10 is created reflects changes in solar activity.
globalicwarming.com.cob-web.org:8888 /solar_activity   (363 words)

 SBI-2 Scientific Objectives   (Site not responding. Last check: 2007-10-12)
Solar irradiance variations affect Earth's climate, but the magnitude of the Sun's intrinsic variation is uncertain.
Solar variability is the main external driver in climate change.
Petro, Foukal, and Kurucz (1985) modeled the range of variations expected, given changes in the source function, effective temperature, and convection in the photosphere, and showed that irradiance variations might be detectable with precise photometry.
sd-www.jhuapl.edu /SBI/Objectives   (2437 words)

 Science archive: Solar variations and climate   (Site not responding. Last check: 2007-10-12)
The temporal variation in the solar activity displays a similarity to that of the mean temperature of the Earth.
I have no doubt that the solar wind and other cosmic phenomena affect climate, but I don't think this particular research is precise enough to say that the temperature rises since 1970 were due mostly to cosmic ray flux.
The mechanisms include solar variation, emergence from the Little Ice Age, lunar energy variation, internal oscillations (such as El Niño), Milankovitch forcing (variations in the Earth’s orbit), ocean variation, biospheric variation, cryogenic variation (variations in the amount and distribution of ice), surface versus satellite temperature variation, and aerosol forcing mechanisms.
www.globalwarming.org /article.php?uid=900   (995 words)

 The Second Annual Lowell Observatory Fall Workshop
The present state of our understanding of the solar irradiance in absolute units, that is on a scale related to the SI standard of irradiance, has an uncertainty of approximately 2 to 5%.
One of the dominant signals of solar variation is related to the 27-day rotation period of the Sun.
Short-term solar variations in particular flares are very dramatic when observed in the ultraviolet, and these transient occurrences have important stellar counterparts.
www.lowell.edu /users/jch/workshop/gjr/gjr-p3.html   (1516 words)

 Global Warming & Solar Variability
Solar variation accounts for less than half of global warming in 20th Century, UA geoscientist finds
Damon testified at the hearing, giving a similar verdict on the limitations of solar variability as an explanation for global warming.
Although there is no direct record of solar variability, he was involved in a successful effort to create a reasonable proxy for it by plotting radiocarbon production.
solar-center.stanford.edu /sun-on-earth/damon.html   (717 words)

 [No title]
Conclusion: multi-decadal solar variations are small, but apparantly do account for a significant part of the observed 20th century warming in the first half of the century.
The problem is that for solar to be strong enough to explain the secular rise in global temperature, it becomes too strong for the observed decadal temperature variation.
The bottom line, however, is that an increasing number of climate researchers think that solar variability is important to global climate change and are working to quantify it.
www.john-daly.com /solar/keller.htm   (3570 words)

 SPACE.com -- Sun's Output Increasing in Possible Trend Fueling Global Warming
The recent trend of a.05 percent per decade increase in Total Solar Irradiance (TSI) in watts per meter squared, or the amount of solar energy that falls upon a square meter outside the Earths atmosphere.
Separate records of sunspots, auroral activity (the Northern Lights) and terrestrial deposits of certain substances generated in atmospheric reactions triggered by solar output, suggest the Sun was persistently active prior to the onset of this Little Ice Age, as scientists call the event.
Large-scale ocean and climate variations on Earth can also mask long-term trends and can make it difficult to sort out what is normal, what is unusual, and which effects might or might not result from shifts in solar radiation.
www.space.com /scienceastronomy/sun_output_030320.html   (1092 words)

 Solar Variation and Earth’s Climate
Researchers believe that changes in sunspot activity or other solar events may affect Earth in ways that are indirect but that can have a significant impact.
The lack of sunspots may have reduced solar radiation by a small amount, perhaps a quarter of a percent—enough to contribute to famines in Europe and allow glaciers to expand.
But the ebb and flow of solar radiation can heat and cool the stratosphere enough to change its circulation patterns, which may have significant impacts on regional climate.
www.ucar.edu /research/sun/climate.shtml   (347 words)

 NAI News Article: Solar Influence, Part II: Effects on and near Earth   (Site not responding. Last check: 2007-10-12)
Again, the solar constant is only an average, and by itself, it doesn’t inform us in the variations in electromagnetic radiation (energetic waves), solar wind, and magnetic field intensity.
But even without solar storms, astronauts are exposed to increased levels of radiation, and it is assumed that they will be exposed to certain “tolerable” levels of radiation during their careers in space.
Since solar wind travels much slower than the speed of light (about 2000 kilometers per second vs. 300,000 kilometers per second), we often have a window of time to prepare for the most violent outbursts.
nai.arc.nasa.gov /news_stories/news_print.cfm?ID=251   (1041 words)

 Mark's Solar Eagle III Hot Wheels Collection   (Site not responding. Last check: 2007-10-12)
This variation dawns a brown color, sheds its eagle graphics and takes the number "03" in place of the original's number "8." Yes, it is a suitable characterization of the car since it is a racer.
This is the second variation to the evolution of the Solar Eagle III Hot Wheel as evidenced by the copyright date on the back of its package.
Solar Eagle III is named so because it is the third generation of solar powered race cars designed and built at Cal State LA. The second car was given the name Solar Eagle II and the first solar powered car built there was named, you guessed it, Solar Eagle.
www.vandalm.com /hotwheels/hotwheels.html   (2371 words)

 Design and Implementation of the Solar Analyst: an ArcView Extension for Modeling Solar Radiation at Landscape Scales
The Solar Analyst model was validated by comparing calculated temporal and spatial patterns of insolation in the vicinity of Rocky Mountain Biological Laboratory (RMBL) with detailed monitoring of insolation, weather, and vegetation.
Estimates of the solar constant range from 1338 to 1368 WM As a result of more precise measurements, the Commission for Instruments and Methods of Observation in 1981 agreed to adopt the World Radiation Center (WRC) solar constant (1367 WM), as is used in the Solar Analyst.
Calculating diffuse solar radiation as a proportion of direct or global solar radiation: The same daily insolation curves for locations with different aspects, along with their viewsheds, were used to examine the validity of calculating diffuse radiation as a proportion of direct or global measurments from sensors.
gis.esri.com /library/userconf/proc99/proceed/papers/pap867/p867.htm   (8020 words)

 [No title]
A maximum percent ozone solar response occurs in the upper stratosphere; a weak or negligible response occurs in the tropical middle stratosphere and a secondary positive response occurs in the tropical and subtropical lower stratosphere.
Introduction One proposed mechanism by which solar variability may influence tropospheric climate involves solar UV-induced changes in stratospheric ozone, with secondary effects on radiative heating and circulation in both the stratosphere and troposphere [Haigh, 1994; Shindell et al., 1999; Kodera and Kuroda, 2002].
Since the observed ozone variation in the middle stratosphere is not significant, it can be concluded that the ozone variation occurring in the lower stratosphere (Figure 2) is mainly responsible for the solar cycle variation of total ozone.
www.qos2004.gr /files/70.doc   (1809 words)

 SRP: EarthWise Solar Energy program FAQ
A solar water heater uses the sun's energy, rather than electricity, to heat water for use in the home.
Solar water heating systems feature a solar collector facing the sun to absorb sunlight and heat the water in your home or business.
It is important to take into consideration the amount of solar variation when the sun is not shining during evening/nighttime hours or during cloudy weather conditions.
www.srpnet.com /environment/earthwise/solarfaq.aspx   (1692 words)

 Sun's Magnetic Activity Varies In 100,000-Year Cycles
Then he went a step further to make a connection with the history of ice ages by looking at oxygen isotopes in the oceans, which reveal the history of how much ice was at the poles and are therefore a measure of average global surface temperature.
One explanation of the 100,000-year cycle was offered by the Milankovitch Theory of Ice Ages in the 1940s, which suggested that the cyclical variations in the earth's orbit around the sun result in the earth receiving varying amounts of solar radiation that, in turn, control the climate.
This explanation is under dispute because the variations of the solar energy in relation to the changes in orbit are very small.
unisci.com /stories/20022/0606022.htm   (741 words)

 Solar constant - Wikipedia, the free encyclopedia
The solar constant is the amount of incoming solar radiation per unit area, measured on the outer surface of Earth's atmosphere, in a plane perpendicular to the rays.
The solar constant is not quite constant; see solar variation.
The solar constant is relatively constant, but varies according to sunspot activity.
en.wikipedia.org /wiki/Solar_constant   (329 words)

 Radiative Transfer Theory
Variation of solar irradiance and insolation with          latitude and time of year
Dips in solar radiation for bands at short end of spectrum due to absorption bands of hydrogen in Sun’s outer atm.
Solar elevation, b, at any latitude, g, varies with time of day, t, (expressed as an angle) as
www.usm.edu /marine/syllabus/MAR602lecture3-2002.htm   (1332 words)

 Sunbathing at Solar Maximum
In space, radiation levels during solar maximum can be much higher than they are at solar minimum, posing hazards to astronauts and orbiting satellites.
Colors indicate the intensity of solar ultraviolet radiation reaching plant and animal life after it has been filtered through stratospheric ozone, clouds and aerosols multiplied by its biological damage potential.
Herman says that daily and weekly variations in the ozone layer are much larger than the effect of the solar cycle.
science.nasa.gov /headlines/y2000/ast05sep_1.htm   (1520 words)

 Publications from 2003 (16+26+13=55)
Inter-network magnetic fields observed during the minimum of the solar cycle.
Centre-to-limb variation of solar granulation in the infrared.
Heating of the solar corona by topological dissipation.
www.solarphysics.kva.se /publications/database/node5.html   (861 words)

 A measurement of the quiet network contribution to solar irradiance variation
Furthermore, network area measurements we have carried out on Ca K spectroheliograms digitized from the Mt. Wilson and NSO/Sacramento Peak archives, for the nine solar activity minima between 1914 and 1996, show no evidence of network area variations large enough to produce a significant long-term component of total irradiance variation.
A network brightness variation of sufficient magnitude is also unlikely, given the linear dependence of solar microwave flux on area of bright structures.
But they suggest that high climate sensitivity to the relatively small changes in solar total and UV irradiance that have been observed, provides a more likely explanation of the global temperature-solar activity correlation.
www.agu.org /pubs/crossref/2001/2000GL012072.shtml   (302 words)

 [36.03] Ground-Based Correlates of Solar Irradiance Variation   (Site not responding. Last check: 2007-10-12)
Ground-based instruments cannot directly measure solar irradiance variablity at the 0.1% level at which it occurs because of the earth's atmosphere.
However, many forms of ground-based solar observations correlate well with solar irradiance variations, and this fact has been used to construct facular-sunspot models which can explain about 90% of the variance of total solar irradiance as observed by spacecraft radiometers.
This paper is a selective review of the current status of the use of ground-based data to understand spaceraft observations of solar irradiance and to apply this understanding to periods before space-based measurements were available.
www.aas.org /publications/baas/v33n4/aas199/7.htm   (132 words)

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