Why does ascending air cool

As air rises, air pressure at the surface is lowered. Rising air expands and cools adiabatic cooling: that is, it cools due to change in volume as opposed to adding or taking away of heat. Sinking air compresses and heats.

As air sinks, air pressure at the surface is raised. Cold air holds less moisture than warm. Just like convection currents with air rising at the equator and sinking at the poles.

These clouds typically grow upward and can grow into thunderstorms. Violent tornadoes are also associated with cumulus clouds. Storms that form at sea begin to dissipate when they reach land, because they can no longer absorb moisture from the ocean. The longer a tropical storm or hurricane stays at sea, the more likely it is to grow in size and strength, for the most part. Frank Girard is a copywriter and marketing consultant who has been working in the field since Equatorial Air Mass Characteristics.

What Are the Characteristics of a Tropical Storm? Mauna Loa Facts for Kids. Open Ocean Facts for Kids. If the air pressure on the outside of the parcel pushing inward is greater than the air pressure inside the parcel pushing outward , then the parcel will be squeezed together or compressed.

As the parcel is compressed, the air pressure inside starts to increase. This continues until the air pressure inside the parcel equals the air pressure outside.

If the air pressure on the outside of the parcel pushing inward is less than the air pressure inside the parcel pushing outward , then the parcel will expand outward. As the parcel expands the air pressure inside starts to decrease. So when an air parcel rises upward in the atmosphere, it must expand because the air pressure surrounding the parcel gets lower See Figure H. This means that the number density of air in the parcel decreases same number of gas molecules but in a larger or expanded volume.

The air in the parcel uses energy to expand increase its size , so the temperature of the parcel also decreases. Mathematically, the pressure, number density, and temperature of a gas are related in an equation called the gas law:.

Pressure decreases when a parcel is lifted. From the gas law, the density x temperature must also decrease.