Map 1 shows a coastline with arrows for a cold ocean current flowing along the shore and arrows for prevailing winds blowing from the ocean toward land. The highlighted coastal region has these long-term averages: mild temperatures year-round and very low precipitation. Based on the map, which explanation is best supported for why this region’s climate (long-term averages, not a single storm) is so dry?
Evidence note: The current direction and wind pattern are shown as the dominant pattern over many years.
- The coast is dry mainly because it is at a high latitude, so latitude alone controls precipitation.
- The coast is dry because cold ocean water cools the air above it, reducing evaporation and limiting moisture available for rain as winds blow onshore over long time periods. (correct answer)
- The coast is dry because one unusually dry year permanently changed the region’s climate.
- The coast is dry because climate is random and does not relate to ocean currents or winds.
Explanation: The core skill is using circulation patterns to explain climate. Climate reflects long-term patterns of temperature and precipitation averaged over many years, not isolated weather events. Winds and ocean currents interact with latitude by moving heat and moisture, where cold currents can cool the air and reduce evaporation, leading to drier conditions even with onshore winds. To check understanding, identify circulation influences like current temperature and wind direction affecting the region's moisture availability. A common misconception is thinking latitude alone controls precipitation, but circulation patterns can create dry climates at various latitudes. Regional climates result from multiple interacting circulation patterns, such as the combination of cold currents and prevailing winds. These interactions explain why some coastal areas remain arid over long periods despite proximity to the ocean.