Since the 1850s researchers have tried to show that variations in seasonal weather are connected in some way with sunspots,...
GMAT Reading Comprehension : (RC) Questions
Since the 1850s researchers have tried to show that variations in seasonal weather are connected in some way with sunspots, the outward sign of an increase in the Sun's activity. However, scientists lacked evidence supporting such a link until the mid-1980s, when van Loon and Labitzke compiled statistical evidence suggesting that a link exists and that it involves winds in the upper atmosphere above the equator which reverse their direction, from east to west or west to east, every twelve to fifteen months. This phenomenon is called the quasi-biennial oscillation (QBO), and although meteorologists have known about the QBO since the 1950s, until the 1980s no one recognized a subtle but statistically significant link between the QBO and certain patterns of weather. When the west to east direction of winds in the upper atmosphere coincides with periods of high solar activity that occur approximately every eleven years, winters in the eastern and central United States are very cold.
On this basis, some meteorologists predicted that the winter of 1988-1989 in the United States would be severe. However, the winter was a mild one overall, and the meteorologists' attempt to make the connection between the Sun and weather on the Earth appeared unsuccessful, until Barnston and Livezey proposed a hypothesis explaining why the prediction had failed. They argued that the prediction had not taken into account another important element in the climate: the more or less regular pattern of fluctuations in the temperature of the surface waters of the tropical Pacific Ocean.
Barnston and Livezey noted that when the water temperature is abnormally high-the phenomenon called EI Niño- the chances of cold winter weather over North America increase. The opposite situation, when surface temperatures are well below normal-La Nina-is far less common. In fact, until late 1988 no one had seen the combination of La Nina, westerly winds in the upper atmosphere, and high solar activity. Thus, according to Barnston and Livezey, La Nina canceled out the effect of the other two climatic factors and caused the mild winter of 1988-1989. Although this hypothesis is plausible, much research remains to be done before meteorologists can establish and explain the effects of increased solar activity on seasonal weather changes.
The author of the passage would most likely agree with which of the following statements about the link between increased solar activity and certain seasonal weather changes on the Earth?
1. Passage Analysis:
Progressive Passage Analysis
| Text from Passage | Analysis |
|---|---|
| Since the 1850s researchers have tried to show that variations in seasonal weather are connected in some way with sunspots, the outward sign of an increase in the Sun's activity. | What it says: For about 170 years, scientists have been trying to prove that seasonal weather changes are linked to sunspots (which show when the Sun is more active). What it does: Sets up the central topic and establishes the historical context Source/Type: Historical fact about research efforts Connection to Previous Sentences: This is our opening sentence - establishes the main topic Visualization: Timeline: 1850s → Present Day: Scientists searching for Sun-Weather connection What We Know So Far: Long-standing research question about Sun-weather link What We Don't Know Yet: Whether they found evidence, what the connection might be Reading Strategy Insight: This tells us the ENTIRE passage will be about this one research question - Sun and weather connections |
| However, scientists lacked evidence supporting such a link until the mid-1980s, when van Loon and Labitzke compiled statistical evidence suggesting that a link exists and that it involves winds in the upper atmosphere above the equator which reverse their direction, from east to west or west to east, every twelve to fifteen months. | What it says: No proof existed until 1985-ish, when two scientists found statistical evidence of a connection involving equatorial wind direction changes every 12-15 months. What it does: Provides the breakthrough moment and introduces the wind pattern concept Source/Type: Research findings by van Loon and Labitzke Connection to Previous Sentences: This directly answers the question from sentence 1! After 130+ years of searching (1850s-1980s), scientists finally found evidence. Visualization: 1850s-1980s: No evidence found Mid-1980s: van Loon & Labitzke discover wind pattern connection Wind pattern: East→West (12-15 months) → West→East (12-15 months) What We Know So Far: Sun-weather link exists, involves changing wind directions What We Don't Know Yet: What this wind pattern is called, how exactly it affects weather Reading Strategy Insight: The "However" signals progress, not contradiction - we're moving from "no evidence" to "found evidence" |
2. Passage Summary:
Author's Purpose:
To trace the historical development of research connecting solar activity to seasonal weather patterns, showing how scientists gradually built understanding through discoveries, setbacks, and refinements of their theories.
Main Point:
Although scientists have made progress in discovering connections between solar activity and seasonal weather patterns, their understanding is still incomplete and requires much more research before they can reliably predict weather based on solar activity.
• The passage never suggests the evidence is "questionable" - in fact, it describes van Loon and Labitzke's findings as "statistical evidence" and Barnston and Livezey's hypothesis as "plausible"
• The author shows continued research progress and refinement, not a dead end
• The final sentence calls for "much research" to continue, contradicting the idea that "future research does not look promising"
• The passage doesn't suggest it's "unlikely" that a link can be established - only that more research is needed
• The author presents La Niña and ocean factors as additional elements in understanding the sun-weather connection, not as replacements for studying solar activity
• This choice misinterprets the passage's message about needing to study multiple factors together, not abandoning solar research
• This choice is too pessimistic - the passage shows research progress and calls for continued investigation
• The phrase "circumstantial evidence" understates what the passage presents as legitimate statistical evidence
• The final sentence encourages more research to "establish and explain" the effects, suggesting confirmation is possible
• This perfectly captures the author's balanced tone throughout the passage
• Acknowledges the legitimate evidence found (van Loon and Labitzke's statistical evidence, QBO patterns, solar cycle connections)
• Recognizes that this evidence isn't yet sufficient for definitive proof, as shown by the failed prediction and ongoing research needs
• Aligns with the final sentence's call for "much research" before scientists can "establish and explain" the effects
• The passage never claims the evidence "clearly supports" the link - instead, it shows evidence that needs further investigation
• The final sentence explicitly states that effects need to be "established" and "explained," indicating the link isn't definitively proven
• This choice is too confident given the passage's emphasis on ongoing research needs and incomplete understanding