How Scientists Measure the Ozone

Measurements of the ozone layer are primarily obtained from advanced satellite instruments. For instance, the TOMS (Total Ozone Mapping Spectrometer) provided invaluable data that helped researchers visualize ozone levels in our atmosphere.

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Methods of Measuring Ozone

Various tools assist scientists in analyzing the ozone levels within vertical columns of the atmosphere. One such instrument is an ozonesonde, which translates to "messenger" in Old English. This device is attached to a balloon that can ascend to over 21 miles (33.8 kilometers) into the stratosphere [source: NOAA]. Upon reaching the stratosphere, it collects air samples to gauge the presence of ozone gas using an electrochemical concentration cell (ECC). The ECC leverages potassium iodide that reacts with ozone, generating an electrical current to quantify ozone concentration [source: NOAA]. To mitigate damage upon landing, the ozonesonde is equipped with a parachute in case the balloon bursts at high altitudes.

Aircraft and Ground-Based Measurements

In addition to ozonesondes, specially designed aircraft can ascend to the lower stratosphere to measure atmospheric ozone. Ground-based ultraviolet (UV) detectors also assess the intensity of UV light that penetrates the ozone layer, providing insights into atmospheric ozone levels. Furthermore, both aircraft and ground stations utilize laser technology for ozone detection.

Satellite Instruments

Scientists utilize multiple satellite instruments to study ozone levels, including the TOMS. This satellite intelligence evaluates the ozone layer by analyzing backscattered UV light, which is the UV radiation reflected back into space by the Earth [source: NASA]. Although the TOMS program concluded after its latest instrument experienced transmission issues, it was instrumental in tracking ozone levels for three decades [source: Spector]. The Ozone Monitoring Instrument (OMI) on the Aura satellite is one of the subsequent tools instituted to measure backscattered UV light.

For further details, explore ozone monitoring equipment.

Understanding Ozone Density

Since ozone exists alongside other atmospheric gases at varying densities and altitudes, comprehending the "thickness" of ozone requires specific perspective. If all atmospheric ozone were condensed into a single layer, it would measure approximately a quarter of an inch (0.6 centimeters) in thickness [source: Fahey]. However, in reality, ozone is dispersed throughout the stratosphere and collaborates with oxygen to shield us from harmful radiation, resulting in an effective ozone layer that extends about 25 miles thick (40 kilometers) [source: Encyclopedia Britannica].

Dobson Units

When assessing total atmospheric ozone, researchers measure the ozone gas concentration in a designated air column using Dobson units (DU), named after G.M.B. Dobson, a forerunner in ozone research. Each Dobson unit signifies a thickness of 0.01 millimeter of ozone gas within a vertical column [source: NASA].

Conclusion

Armed with these measurement techniques, scientists have cultivated a deeper understanding of stratospheric ozone levels, leading to various significant findings that warrant further discussion.