Remotely operated aircraft measure Arctic soot

Over the past 100 years, air temperatures near the surface in the Arctic
have increased about twice as fast as the global average. The spring melting of Arctic snow and ice
is starting earlier, the melt season lasts longer, and sea ice
extent has decreased. When the reflective snow and ice melts, darker land and ocean surfaces are exposed
to solar heating. Black soot, produced by burning diesel fuel,
agricultural fires, forest fires, and wood-burning stoves, is transported by winds to the Arctic, where it is deposited leading to further darkening of snow
and ice surfaces. The darkened surfaces absorb heat from the
sun and enhance the warming of the Arctic atmosphere. In order to understand and mitigate the climate
impacts of soot, we must know the source of the soot transported
to the Arctic. Small, new, remotely-operated, unmanned aircraft
are key to providing this information. NOAA first deployed this new aircraft in April
2011, in Svalbard, Norway, as part of an international field study. It weighs 62 pounds at take-off, has a wing
span of 8.5 feet, and can fly for 4 hours. It carries instruments that measure the number
of particles in the atmosphere, their soot content, and tracer compounds that reveal
information about the source of the soot. Other instruments measure temperature and
relative humidity in order to characterize cloud layers and stratification of the atmosphere. To supplement the aircraft measurements, teams
of scientists on the ground make detailed measurements of surface reflectivity, snow pack characteristics, and soot concentrations
in snow. Since climate models indicate that reducing
the concentration of short-lived soot will reduce the rate of warming in the Arctic faster
than reductions in long-lived greenhouse gases, reducing soot emissions is a first step that
would buy time, until reductions of the longer-lived greenhouse gases can be implemented. Data from NOAA’s new program are important
for developing mitigation strategies to reduce emissions of soot that impact Arctic climate.

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