Earth and Space Sciences Regents, August 2026, question 43
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What the figure shows
The passage describes the 2022 Hunga Tonga-Hunga Ha'apai (HTHH) eruption, which put layers of strongly enhanced water vapor between 19 and 28 kilometers (km). It states that water vapor plays a large role in climate feedbacks and is a greenhouse gas. Four graphs show water vapor mixing ratio in parts per million by volume (ppmv) against altitude in km, 24 hours after the eruption: 1: Broome, points from about 27 to 31 km, with the largest values, slightly above 1000 ppmv, near 29.5 km; 2: Darwin, a peak near 1000 ppmv at about 27 km; 3: Gove, a peak near 200 ppmv at about 23.5 km; 4: Willis Island, a peak near 80 ppmv at about 21 km. The four choices are small tables, each with an Energy Flow column and a Highest Atmospheric Layer column. Choice 1: Increased energy flow to atmosphere, Troposphere at Darwin. Choice 2: Decreased energy flow to atmosphere, Stratosphere at Willis Island. Choice 3: Decreased energy flow to atmosphere, Troposphere at Gove Island. Choice 4: Increased energy flow to atmosphere, Stratosphere at Broome.
How to think about it
This question has two parts, so check both columns. For energy flow, think about what a greenhouse gas does with the infrared energy given off by Earth's surface. For the layer, compare the heights of the water vapor peaks in the four graphs, then open the Cross Section Model of Earth's Lower Atmosphere on page 19 of the reference tables and see how high the tropopause, the top of the troposphere, reaches.
Which table identifies how the volcanic eruption of HTHH most likely affected the flow of energy to Earth’s atmosphere and identifies the highest atmospheric layer of peak water vapor content? Energy Flow Highest Atmospheric Layer Energy Flow Highest Atmospheric Layer Increased energy flow to atmosphere Troposphere at Darwin Decreased energy flow to atmosphere Troposphere at Gove Island
Reference table: Cross Section Model of Earth's Lower Atmosphere (2024 edition, page 19)