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Aurorae, colorful curtains of light seen from Earth at high latitudes, are caused by charged particles energized by the Earth's magnetic field colliding with nitrogen and oxygen in the thermosphere | |
Voyages into the Atmosphere
The Earth's atmosphere, a layered sphere of gas extending
upward more than 600 km from the surface, forms the environment for terrestrial
life. The atmospheric sciences division at LASP studies the chemical and
dynamical processes that occur in and link the different layers: the troposphere,
where weather occurs; the stratosphere, where a blanket of protective ozone
lies; the mesosphere, the home of beautiful noctilucent clouds; and the
thermosphere, host to the colorful northern lights.
LASP became a world leader in designing, building, and
operating small satellites with the successful launch and operation of the
Solar Mesosphere Explorer (SME) in the early 1980s. This primarily
student-operated mission provided new information about the structure and
content of the Earth's middle and upper atmosphere, and was the foundation for
many future investigations at LASP and around the world. For the first time,
the distributions of important gases such as ozone and nitrogen dioxide were
mapped on a near-global scale. SME also provided some of the first satellite
measurements of polar mesospheric clouds (PMCs). |
Exploring Energetic Particles
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The SNOE spacecraft was designed, built, and tested by a team of students under the supervision of LASP engineers. |
Following in the footsteps of the successful SME mission, in 1998 LASP launched the Student Nitric Oxide Explorer (SNOE), dedicated to measuring solar radiation and particle effects on the upper atmosphere. The SNOE instruments continue to provide excellent data enabling us to probe the mysteries of the aurora. The aurora, colorful curtains of light seen from Earth at high latitudes, are
caused by charged particles energized by the Earth's magnetic field colliding
with nitrogen and oxygen in the thermosphere. Particles with even greater
energy penetrate to the lower thermosphere and mesosphere, forming nitric
oxide that can descend to the stratosphere and contribute to the destruction of
ozone. LASP scientists and students are contributing to the understanding of
these important atmospheric processes.
Shimmering Clouds and Vanishing Ozone
LASP scientists also study ozone depletion in the polar lower
stratosphere, a phenomenon closely linked to the occurrence of polar
stratospheric clouds (PSCs). These rainbow-colored, shimmering clouds form only
over the polar regions during the winter and early spring. PSCs set the
conditions for the yearly ozone hole in Antarctica, and for significant ozone
loss in the Arctic as well. When stratospheric ozone is depleted, more
ultraviolet light penetrates to the Earth's surface, causing damage to
terrestrial life. LASP scientists employ theoretical models and data from
numerous satellite and aircraft instruments to quantify the relationship
between PSCs and polar ozone depletion. The extent of ozone loss is monitored
each year to gain a predictive understanding of stratospheric chemistry and
transport.
A dust storm sweeps from Africa into the Atlantic in February 2000. (Photo courtesy of NASA/JPL/Caltech)
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Learning About the Lower Atmosphere
LASP is now emerging as an important player in the study of
tropospheric chemistry and dynamics. Aircraft instruments designed and built at
LASP have made successful measurements of tropospheric ozone and other
atmospheric gases, and LASP has had project science responsibility for numerous
major field missions. LASP also has a vigorous tropospheric theoretical program
focused on cloud microphysics, the transport of dust and ash around the globe
after desert storms and biomass burning, and the effects of aerosols and clouds
on climate. This program is linked directly to the planetary science division
at LASP, seeking to apply knowledge gained by modeling the evolution of the
Earth's atmosphere and climate through geologic history to other planets.
Shining Skies and Climate Change
A very compelling problem in atmospheric science is to understand how and why the climate is changing. Polar mesospheric clouds are wispy, striated ice clouds that form 83 km above the north and south poles during the summer. PMC's, or noctilucent ("night-shining") clouds as they are known to ground based observers, are considered possible indicators of climate change. They are believed to respond dramatically to small changes in the environment and can be thought of as "the miner's canary of global change." PMC's have, in the last two years, been observed far south of their normal latitude. They have been seen in Colorado and Utah - LASP's SNOE satellite has actually measured them at these low latitudes. Does this represent a change in our atmosphere? LASP scientists are combining information from SME, SNOE, and various ground-based and rocket measurements to gain new insight into the processes that affect PMC growth and dissipation.
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