Thermodynamics and Atmospheric Stability Flashcards

What is a capping inversion (or 'cap') in severe weather forecasting?

Answer: A warm layer aloft that prevents premature convection while allowing CAPE to build

A capping inversion is a warm layer in the lower troposphere that suppresses convection until sufficient forcing breaks the cap, often leading to explosive thunderstorm development.

What does the K-Index measure in severe weather forecasting?

Answer: Thunderstorm potential based on temperature, dew point, and lapse rate

The K-Index combines low-level moisture, temperature lapse rate, and mid-level moisture saturation to estimate thunderstorm potential.

Virtual temperature is used in atmospheric thermodynamics to account for what effect?

Answer: The effect of water vapor on air buoyancy and density

Virtual temperature treats moist air as equivalent dry air, accounting for the lower density of water vapor relative to dry air.

The Brunt-Väisälä frequency measures what atmospheric property?

Answer: Buoyancy oscillation frequency of a displaced air parcel in a stable layer

The Brunt-Väisälä (or buoyancy) frequency describes how fast a displaced parcel oscillates vertically in a stably stratified atmosphere.

Convective instability (potential instability) is assessed by examining changes in what variable with height?

Answer: Equivalent potential temperature (theta-e)

Convective (potential) instability exists when theta-e decreases with height, meaning the layer becomes unstable if lifted as a whole.

What is the significance of the wet-bulb potential temperature in air mass analysis?

Answer: It is conserved in both dry and moist adiabatic processes, identifying airmass origins

Wet-bulb potential temperature is conserved through both dry and saturated adiabatic processes, making it an excellent tracer of air mass identity.