問題詳情

III. Reading Comprehension (5 %):     While there have been countless attempts at correlating sunspot cycles with such diverse phenomena as the economy, cropyields, and the weather, there has been little evidence to support these correlations. The past few decades have seen a renewedinterest in the sun-climate relationship with a comprehensive analysis of many different historical records of solar observation.Later in the seventeenth century, a period known as the Maunder Minimum, there were virtually no sunspots observed, indicating a “quiet” period in the sun’s activity coinciding with the height of a time known as the Little Ice Age, a period oflower temperatures in Europe. Once this evidence had been synthesized, it has become much clearer that there are indeedrobust correlations between the Earth’s temperature and sunspots. Perhaps the most important development in thesolar-climate link came when satellites were developed to measure, in rough terms, the Total Solar Irradiance (TSI), a factorshown to be directly related to these “activity” cycles. At the maxima of these cycles, there are more sunspots (magneticphenomena that attenuate local irradiance), but new instruments show that these dark sunspots are more than compensated forby bright areas on the sun called faculae; therefore, the overall irradiance increases in correspondence with higher numbers ofsunspots.                 Unfortunately, identifying this evident increase in minimum values as a trend provokes concern, as there have been onlytwo minima ever measured in this way. We must be aware that the warming trend in the surface temperature goes far beyondthe last two decades, and that an extension of the solar record is necessary to assess whether solar activity and irradiance isindeed increasing at the minima of the cycles and what the potential effect on the climate may be. The solar record has beenextended by the use of the historical sunspot records already mentioned and correlations have been drawn between solarirradiance and the temperature curve since 1610, suggesting a predominant solar influence in the pre-industrial period. Butsince 1860 only half the observed warming could be attributable to the irradiance increase, indicating that some other influenceis becoming more influential in controlling the temperature change: more likely industrial carbon-dioxide.     Recent studies of global warming have necessitated a more comprehensive effort to quantify the natural climate variabilityso that the residual change may be attributed to the anthropogenic emissions of greenhouse gases. This attempt atquantification of the many different forces effect on the climate has reemphasized the complexity of the climate system and thesimultaneous interaction of many influences. Solar irradiance may indeed account for some of the temperature increasesrecorded over the last several decades, but as the atmospheric CO2 rises, due to the exponential increase in emissions fromindustrial sources, the influence of solar variability on the Earth’s climate will most likely decrease, and its relativecontribution will be far surpassed by “greenhouse” gases.
16. The author focuses primarily on _______
(A) giving a brief overview of some recent scientific developments in solar physics and explaining their possible implicationsfor future research.
(B) outlining the specific reasons why a long standing problem in solar physics is thought to be soluble at last.
(C) presenting two competing scientific theories for the cause of post-industrial climate change and evaluating the body ofevidence behind each one.
(D) pointing out the success of a certain line of scientific inquiry into the terrestrial effects of solar activity while qualifying itssuccesses with regard to climate change.

參考答案

答案：D
難度：適中0.5
統計：A(0),B(0),C(0),D(0),E(0)

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