solar variation and climatic changes
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- 1. SOLAR VARIATION AND CLIMATICCHANGESBy- Dr. Vinay Kumar PandeyDr. Ajai Mishra,Dr. Shashank Shekhar Mishra
- 2. INTRODUCTION Sun covers total 99.86% mass of oursolar system and 3,33,000 times of theEarth mass. Earth is IIIrd planet in the solar systemand having a unique position due tolife. Life on Earth depends on energyreceived from the sun. The Sun is the source of energy thatcauses the motion of the atmosphereand thereby controls weather andclimate. Any change in the energyfrom the sun received at the Earthssurface will therefore affect climate. The Earth climate has always beingchanging and well documented inhistorical as well as geological records. The sun has a magnetic field that flipsapproximately every 11 years. Sunspotsand solar flares are caused by themagnetic activity of the sun. The sunspots and solar flares can affectthe earth by changing the amount ofincoming sunlight and interacting withthe earths magnetic field.
- 3. SUNSPOTS
- 4. OBJECTIVE Discuss the solar variation and its effecton Earth & climate. Discuss the Past climate change andsolar variationEffect of Solar Activity on Earth Climate
- 5. MEASURMENT OF SOLAR VARIATION Solar variation is the change in the amount of radiation emitted by the Sun and in its spectraldistribution over years to millennia. These variations have periodic components, the main one beingthe approximately 11-year solar cycle. In recent decades, solar activity has been measured bysatellites, while before it was estimated using proxy variables . Variations in total solar irradiance were too small to detect with technology available before thesatellite era, although the small fraction in ultra violet light has recently been found to varysignificantly more than previously thought over the course of a solar cycle. Total solar output isnow measured to vary (over the last three 11-year sunspot cycles) by approximately 0.1%,or about1.3 Watts per square meter (W/m2) peak-to-trough from solar maximum to solar minimum duringthe 11-year sunspot cycle. (Weart & Spencer, 2003) The intensity of solar radiation reaching Earth has been relatively constant through the last 2000years, with variations estimated at around 0.10.2%. Solar variation, together with volcanicactivity are hypothesized to have contributed to climate change, for example during the MaunderMinimum Changes in solar brightness are too weak to explain recent climate change. (Scafetta N.,West B. J., 2006)
- 6. RECORD OF SOLAR ACTIVITY Chinese observation 1000 year earlier (through loess clouds). European telescopic observation began 1610. 14C/12C ratio is high when sunspot number is low. Dating of tree rings demonstrates a pattern of deviations. (Merril and Mc Elhinny, 1983) An active sun result in a strong solar wind; deflects cosmic rays and decrease 14Cproduction: positive 14C anomaly= cold climate (Wang et al. 1996). Satellite observations indicate that during 11 year cycle sunspot minimum, solarirradiance is lower (0.1%), interplanetary magnetic field weaker. (Radick,1990; Wang etal., 1996; Willson, & Hudson 1988; Willson, et al. 1985) .
- 7. SOLAR VARIATION AND CLIMATE CHANGE From 1645 to 1715 there were almost no sunspots. This period is called the Maunderminimum, the peak of the Little Ice Age, a cool period affecting Europe from the 1300s to the1800s. (Eddy, J.A., 1981) Data from 8000 year old bristle cone pine tree indicate 18 periods of sunspot minima in thelast 7800 years. Maxima of sunspot cycle length occurred in 1770, 1845 & 1940 (Eddy, J.A.,1981). The Dalton minimum, a 25 year span at the beginning of the 1800s when sunspots were halfas numerous as normal, corresponds to the end of the Little Ice Age. Some people claim there is a connection between the 22 year solar cycle and the roughly 20year drought cycle in the Great Plains. One interesting bit of information is the ozone layer tends to reach a maximum at the sametime as the solar maximum, allowing the ozone layer to absorb the excess radiation. This is thought to affect the tropical Hadley cell circulation and the tracks of mid-latitudecyclones.
- 8. Milankovitch Cycles (Solar irradiance) and Temperature received at 65 N in July(Source: http://www.climatedata.info/Forcing /Forcing/milankovitchcycles_ files/BIGw02-milankovitch-and-temperature.gif.gif
- 9. Source: http://a-sceptical-mind.com/an-alternative-solar-theory
- 10. SUNSPOT CYCLESVery weak forcing, but significant climate responses to it.- Sunspots +Source: http://oilprice.com/Energy/Energy-General/The-Natural-Chaos-Of-Climate.html
- 11. LITTLE ICE AGE (1500-1850 AD)Cooling was the result of lower solar radiation and some bigvolcanic eruptions.
- 12. NEW DIRECTIONS IN SOLAR VARIABILITY ANDCLIMATE CHANGE The Total Solar Irradiance has changed byonly 0.3-0.6% since the early 1800s. The climate has warmed by 0.5 to 1.0degrees C in the same period. The correlation between the solar andclimate records can be seen in this figurecomparing polynomial fits to the sunspotrecord and the global mean sea-surfacetemperature. The Similarity is remarkable. It is difficult to imagine that two unrelatedphenomena can have such similar features.Sunspot NumberSea Surface Temperature .01 K Departurefrom MeanSource: www.swpc.noaa.gov/AboutUs/Review2000/Solar_Irrad_Poster.ppt
- 13. CONCLUSIONS Solar irradiance variability ranges from 0.1% to factors or 10 or more depending onwavelength. There is strong evidence that the past solar output has changed and thischange has been responsible for changes in the climate. If the sun is cyclic in nature, itmay be possible to forecast future solar irradiance changes. Forcing is very weak (in visible spectrum), only 0.1-0.2%, so climate response shouldbe weak. Climate response is actually quite high - still not sure why. One possibility is UV part of spectrum - much greater changes (10%) suggests that global climate is very sensitive
- 14. REFERNCES Eddy, J.A. 1981: Climate and the role of the Sun. In Rotberg and Rabb , 145--67 (5) (1981). Wang, L., Wheeler, J. C., Li, Z., & Clocchiatti, A. , ApJ, 467, 435. First citation in article | Cross Ref |ADS(1996) Radick, R. R., Lockwood, G. W. & Baliunas, S. L. Science 247, 3944 (1990). Willson, R. C. & Hudson, H. S. Nature 332, 810812 (1988). Weart, Spencer. Changing Sun, Changing Climate?. The Discovery of Global Warming . HarvardUniversity Press. ISBN 0-674-01157-0. (2003) Lean, Judith . Evolution of the Suns spectral Irradiance Since the Maunder Minimum. GeophysicalResearch Letters 27 (16): 24258.: (2000)