## Section3.1Modes of energy transfer

NOAA Jetstream: https://www.weather.gov/jetstream/heat

Energy is the capacity to do work (when a force acting on an object causes it to move), and can be further divided into kinetic and potential energy.

Considering a parcel of air in the atmosphere, its temperature would describe the average kinetic energy of its atoms and molecules. The higher the temperature of a gas, the fast its atoms and molecules are traveling through three-dimensional space. Temperature is typically expressed in F, C, or K:

Heat refers to the transfer of energy from warmer objects to colder objects and represents the total thermal energy of a system. It is distinct from temperature!

The amount of heat depends upon ($$q=mC_s\Delta T$$):

• the total amount of the the material in the system

• the thermal properties of the material

In atmospheric systems, energy is transferred by

• conduction (contact between substances)

• convection (vertical movement of air parcels)

• advection (horizontal movement of air masses)

• latent heating (energy released by phase changes of water)

Latent heat effects can be found in two common atmospheric processes:

• ice $$\rightarrow$$ liquid water $$\rightarrow$$ water vapor (absorbs heat)

• water vapor $$\rightarrow$$ liquid water $$\rightarrow$$ ice (releases heat)

Cloud formation (for example) will release heat to the surrounding atmosphere. This slows the rate of cooling with altitude (i.e., the lapse rate decreases).