Study 3 Temperature and Atmospheric Stability with 12 free online flashcards. Review key terms, definitions, and concepts with this interactive flashcard deck.
Why is a surface air-temperature sensor placed in a ventilated shelter?
A ventilated shelter shields the sensor from direct sunlight and nearby surface heat, helping it measure air temperature rather than direct exposure to those sources.
How do you convert Celsius to Kelvin?
Convert Celsius to Kelvin by adding 273.15: K=∘C+273.15. Kelvin is commonly used in scientific calculations.
How does radiation transfer energy in the atmosphere–surface system?
Radiation transfers energy by electromagnetic waves. Sunlight warms Earth's surface, and Earth emits infrared radiation.
How can clouds affect daytime warming and nighttime cooling?
Clouds can limit daytime warming by reflecting sunlight and reduce nighttime cooling by absorbing and re-emitting some outgoing infrared energy.
What is the lapse rate, and what is a common tropospheric average?
The lapse rate is the rate of temperature change with height. A common average for the troposphere is about 6.5∘C per kilometre, but it varies.
How does an air parcel's temperature change as it rises or sinks?
As an air parcel rises into lower pressure, it expands and cools; as it sinks, it compresses and warms.
How does saturation change an air parcel's cooling rate as it rises?
An unsaturated rising parcel cools at the dry adiabatic lapse rate, about 9.8∘C per kilometre. Once saturated, condensation releases heat and the parcel cools more slowly, at a variable moist rate approximated as 6∘C per kilometre.
How do stable and unstable air differ in their effect on vertical motion?
Stable air resists vertical motion: a displaced parcel tends to become cooler and denser than its surroundings and return. Unstable air supports ascent when a rising parcel remains warmer and less dense than its surroundings.
When is the atmosphere conditionally unstable?
Conditional instability occurs when the environmental lapse rate lies between the moist and dry adiabatic rates. An unsaturated parcel may resist rising, while a saturated parcel may continue rising.
What is conduction, and how deeply does it affect air near the ground?
Conduction transfers heat through contact. It warms only a shallow layer of air touching the ground because air is a poor conductor.
How does convection redistribute heat in the air?
Convection transfers heat as air moves: warmer, less-dense air rises while cooler air sinks or moves in to replace it.
What is advection?
Advection is the horizontal transport of warm or cold air by wind.