 |
QuikTOMS
Animations
Following on a legacy of 23 years of daily mapping of the Earth's ozone layer,
NASA will launch the fifth TOMS instrument aboard the QuikTOMS spacecraft. The
Total Ozone Mapping Spectrometer (TOMS) continuously monitors changes of the Antarctic
ozone hole, global and local ozone levels, as well as sulfur dioxide and ash from
volcanic eruptions, smoke from forest fires and the flux of ultraviolet radiation
reaching the Earth's surface.
 QUIKTOMS
IN ACTION:
Built in just two years rather than the traditional three to five, the Quick Total
Ozone Mapping Spectrometer (QuikTOMS) will take over for the TOMS spacecraft in
monitoring the Arctic and Antarctic ozone levels, sulfur dioxide, ash, smoke from
fires and ultraviolet radiation reaching the Earth's surface. Perhaps most importantly,
QuikTOMS follows on a 23-year legacy; this kind of extended period of observation
allows scientists to separate human-forced changes from natural atmospheric variations
and to help quantify the individual roles of these factors. Of recent note, researchers
are hoping to see some ozone recovery as a result of actions like the 1987 Montreal
Protocol that limited chloroflourocarbon (CFC) production and use.
 THE
ANTARCTIC OZONE HOLE: The year 2000 marked the largest Antarctic hole ever
observed. Using data from NASA's Total Ozone mapping Spectrometer (TOMS), scientists
can monitor polar ozone levels to gain a better understanding of exposure to harmful
radiation, and get a good idea of how the climate is changing. The gap last year
reached 28.3 million kilometers squared, roughly three times the size of the United
States.
 THE
ANTARCTIC OZONE LEGACY: Continuous long-term monitoring of ozone levels is
crucial in determining how much ozone loss is attributable to human activities
and how much is the result of natural atmospheric processes. TOMS instruments
have been in space since 1978 monitoring the ups and downs of the ozone and now
watch with a hopeful eye for changes resulting from political agreements, like
the 1987 Montreal Protocol limiting chloroflourocarbon (CFC) production and use.
ARCTIC
OZONE LAYER animation - While not the 'hole' that exists over the Antarctic,
the depleted region of ozone in the Arctic reached its lowest point in 1999 to
an altitude of nearly 60,000 feet. The dramatic drop in Arctic stratospheric ozone
levels is attributed to extremely low temperatures leading to the formation of
Polar Stratospheric Clouds at an earlier date, despite very dry conditions in
the stratosphere. These clouds alter chlorine from its benign molecular form to
chlorine monoxide, an ozone-destructive compound.  VOLCANIC
ASH: When Mt. Pinatubo erupted on June 15, 1991; it was the largest volcanic
event in nearly a century with global consequences. Global average temperatures
were one degree (F) cooler for over a year due to the massive injection of dust
and gases into the upper atmosphere and stratospheric aerosols increased by over
20 times. In addition, the protective ozone layer in the upper atmosphere weakened
for more than a year from the gases injected into the stratosphere.
Fortunately
the Pinatubo eruption also marked one of the largest climatic events to be observed
by a fleet of spacecraft, creating one of science's greatest lab experiments.
The TOMS instrument on the Earth Probe spacecraft in particular observed the affected
ozone and the aerosols, as seen here. The aerosols resulted from many thousands
of tons of sulfur dioxide gas being sent into the stratosphere where it was converted
to sulfuric acid particles, or aerosols. It was these particles that helped to
reflect sunlight and cool the Earth for a year.  AEROSOLS
IN AFRICA: As part of the 2000 SAFARI field campaign in southern Africa, scientists
studied pollution and fires - both controlled and natural from space. Here, TOMS
aerosol data is combined with fire data from the Advanced Very High Resolution
Radiometer (AVHRR) onboard the NOAA-14 satellite. The unprecedented number of
fires generated large amounts of aerosols.
Tiny
particles suspended in the air, approximately 90% of the aerosols trapped in the
atmosphere originated from volcanoes, dust, forest and grassland fires, living
vegetation and sea spray. Tracking aerosols is crucial for determining their influence
on climate change - at the moment it is unclear whether aerosol content is constant,
diminishing, or increasing, or even if they are warming or cooling the planet.  SMOG
ACROSS OCEANS: A mixture of smoke and fog, smog is made up of particulates
that are formed by a chemical reaction triggered by sunlight. Between July and
October of 1997 the tropospheric ozone (smog) levels rose in the Indian Ocean
and around Southeast Asia. Smog from biomass burning in Africa traveled across
the sea too, combining with Indonesian smog to create a canopy over the region
with the highest levels on October 22, 1997. Red denotes high concentrations of
ozone and green indicates lower levels while smoke from fires is white as seen
by TOMS.
 GROUND-LEVEL
UV EXPOSED: With decreased ozone levels come elevated levels of ultraviolet
exposure, radiation that can reach ground level. TOMS tracks UV-B radiation measured
at 290-320 wavelengths. The most dangerous form, it can cause everything from
sunburns to skin cancer to cataracts. Worldwide and US measurements of UV-B levels
are shown for the year 2000.
Back
to Top |
