Two Goddard scientists in the late 60's developed the
Backscatter Ultraviolet (BUV) instrument to study the Earth's ozone
layer from satellites. The first BUV instrument was launched on
Goddard's Nimbus-4 satellite in April 1970. More than a dozen
instruments of increasing sophistication have been launched in the past
36 years on NASA, NOAA, Japanese, Russian and ESA satellites and many
more are currently in development. Originally designed to measure ozone
density near 40 km, the buv instruments have played a central role in
monitoring changes in the Earth's ozone layer and other trace gases
down to the ground. Maps of the Antarctic ozone hole produced by
Nimbus-7 TOMS in 1985 convinced the public and policy makers around the
world on the seriousness of the ozone depletion problem leading to
International treaties to phase out ozone destroying substances.
Improvements in retrieval techniques have allowed these
instruments to measure sulfur dioxide injected into the atmosphere in
volcanic eruptions, track regional transport of smoke from
biomass burning, and observe inter-continental transport of mineral
dust lofted up by winds from the Earth's major deserts. Improvements in
the instrument sensitivity in the last decade have made it possible to
observe boundary layer pollutants, such as NO2 and SO2, as well as
several trace gases (HCHO, CHOCHO, BrO) involved in air quality
chemistry. A journey through the history of the buv measurements
provides a fascinating glimpse into the history of a field that NASA
initiated as "curiosity-driven research", which nonetheless altered the
course of a multi-billion dollar global industry and has forever
altered our perception about the fragility of our environment.