Hands-On, Minds-On Meteorology
Description | Programming | Operation

Lifting Air (Moist w/Sounding)


The Lifting Air (Moist w/Sounding) program allows students to view a microscopic piece of moist air and manipulate it's initial temperature and environmental sounding, water content, and pressure (altitude) to see how the molecule's properties react.

click for whole shot



The primary objective is to extend the understanding gained from previous Lifting Air programs and extend it to an atmospheric temperature profile and begin to look into issues of stability. A secondary objective is to use the graphing tool to graph interesting relationships.




The Moist w/ Sounding version of this program shows the same parcel of moist air as in the Moist version. The new addition is of the customizable sounding. This sounding becomes the environment that the parcel will lift in, and serves as a way to introduce elements of stability.

Instead of the free-flow style of simply moving the parcel up and down, this parcel initially sits at the bottom of the column. After setting the environment and parcel parameters, the student lifts the parcel to a pressure level of their choice (displayed by a yellow line on the sounding). They then watch the parcel as it rises to that level. Then depending on the stability of the parcel in its environment, can remain where it is, sink, or continue to lift.

The theory behind the parcel in Lifting Air (Moist w/Sounding) program can be found in the parcel controlling class



See ParcelSet*

Graphics and Visualization
Once condensation has occurred, it is often difficult to determine how many water molecules are included in the clump, so when a condensed liquid droplet has accumulated 4 or more water molecules, a small number is placed above it.

Also, at the moment of condensation, a small quick explosion-looking image is shown and quickly disappears. These flashes represent the release of latent heat for that individual condensation occurrence.

Also See Condensation
Condensation Process

See Condensation and Water Collisions


See ParcelSet*


See ParcelSet*



Running the Program

  • Click the link for Lifting Air (Moist w/Sounding).
  • While stopped, select a Temperature and water content by sliding the appropriate scrollbars.
  • Customize the sounding by clicking and dragging the red control points to the left (colder) and right (warmer).The temperature of that point will show when dragged.
  • Once started, change pressure by sliding the external pressure scrollbar or by clicking and dragging the parcel up (not down).Once the desired level is reached, release the mouse to start lifting the parcel.
  • A yellow bar will show on the sounding the altitude of the parcel (in pressure).
  • The parcel will rise to the yellow line, and then, depending on its stability will either rise further, return toward the ground, or remain in its new position.
  • Start and Stop the molecules by clicking the appropriate button.
  • Use the checkbox to toggle the visibility of the dry air molecules.
  • This program will run better with the Dry Air molecules invisible.
  • Enable the Graphing Tool by click the appropriate button.
  • The temperature the air parcel will have is plotted on the sounding as a cyan curve.
  • The positive area (representing CAPE) will be shaded reddish-brown.
  • The parcel will stop rising at the equilibrium level.

Extra Knowledge



Department of Atmospheric Sciences
University of Illinois at Urbana Champaign

Created by Dan Bramer: Last Modified 07/27/2004
send questions/comments to bramer@atmos.uiuc.edu