十万个为什么·科学启蒙30篇（4）

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为什么沙漠昼夜温差大

Deserts have very little humidity, so air holds almost no water vapor to trap heat.
During the day, sunlight heats dry sand and rock surfaces rapidly without cloud cover.
At night, this stored heat escapes quickly back into space because there’s no insulating moisture layer.
The lack of vegetation and clouds means no barrier slows radiative cooling after sunset.
Temperatures can drop over 30°C within hours once the sun disappears below the horizon.
Thermal inertia of desert soil is low, so it cools much faster than ocean water or moist earth.
Radiation dominates heat loss in deserts, unlike convection or conduction in humid regions.
Scientists use satellite data to compare desert cooling rates with tropical forest patterns.
This extreme variation shapes how desert animals behave and when they hunt or rest.
Engineers designing solar farms in deserts must consider thermal stress on materials from daily swings.