September 04, 2000:
GLOBE Unveils New Atmosphere Protocols
More schools report atmospheric data and in larger quantities than all other GLOBE data. Still, there is more to the atmosphere than clouds, temperature, and precipitation. GLOBE students will have the opportunity to measure more properties of the atmosphere and increase their contributions to understanding the global environment starting in September 2000.
Clouds play a major role in determining whether sunlight reaches Earth's surface and how much thermal radiation leaving the surface escapes to outer space. Aerosols in the atmosphere, often visible as haze, have similar effects. Students can measure the concentration of aerosols using a photometer. This instrument is pointed at the sun enabling students to read and report voltages generated by red and green detectors in the instrument. Barometric pressure readings aid in the interpretation of aerosol measurements so a new protocol also is provided for this measurement.
Precipitation is a critical part of the global water cycle, telling us how much water is being transferred from the atmosphere to the surface. The amount of water evaporating from the surface into the air depends on the relative humidity of the atmosphere. GLOBE students can now measure and report relative humidity data using one of two measurement techniques.
Knowing relative humidity, temperature, and pressure tells us how much water vapor is in the air. This is one of the chemical constituents of the atmosphere that varies greatly; another is ozone that is produced through the action of sunlight on hydrocarbons, nitrogen oxides and other trace chemicals in our air. GLOBE has supported efforts to improve a technique for measuring the amount of ozone in the air using a chemically sensitive test strip and a special reader that scans the strip and provides observations of ozone concentration that are accurate to 10 parts per million.
See the Teacher's Guide for more information on new protocols.