At 15-30°N, air masses formed over the Pacific Ocean are moved by prevailing westerlies, where they encounter extensive north-south mountain ranges. Which statement best describes the outcome of this encounter between a landform and an air mass?
A) The cool, moist Pacific air heats as it rises, releasing its precipitation as it passes the tops of the mountains. This now warm and dry air cools as it descends on the leeward side of the range.
B) The warm, moist Pacific air rises and cools, releasing precipitation as it moves up the windward side of the range. This now cool and dry air mass heats up as it descends on the leeward side of the range.
C) The cool, dry Pacific air heats up and picks up moisture from evaporation of the snowcapped peaks of the mountain range, releasing this moisture as precipitation when the air cools while descending on the leeward side of the range.
D) These air masses are blocked by the mountain ranges, producing high annual amounts of precipitation on the windward sides of these mountain ranges.

Question

Quizplus · Accepted Answer

When warm, moist air encounters a north-south mountain range, it rises and cools as it moves up the windward side of the range. As the air cools, it releases its moisture as precipitation. This produces high amounts of precipitation on the windward side of the range. The now cool and dry air mass then moves over the top of the mountain range and begins to descend on the leeward side. As the air descends, it heats up and becomes warmer and drier, which can lead to arid conditions on the leeward side of the range. This process is known as the orographic effect. Therefore, option B is the correct answer.

At 15-30°N, Air Masses Formed Over the Pacific Ocean Are