Cloud Radiation
-- Cloud Radiation --
Atmospheric Radiation and Climate Program
Dan Lubin and Robert H. Whritner
One of the major physical components of climate change is the way in
which solar energy is redistributed in the Earthatmosphere system. This sub-
ject also includes the simultaneous emission of thermal (infrared) energy from
the Earth's surface and its partial entrapment by the atmosphere (the "green-
house" effect). Globally well-mixed increases in carbon dioxide abundance are
believed by many to be enhancing the greenhouse effect and increasing the
global surface temperature field. This could have serious repercussions for Arctic
Ocean climate, as the Arctic Ocean surface exists for much of the year at
temperatures just below the freezing point of water. A small increase in surface
temperature could potentially have a large impact on the geographic extent of
Arctic sea ice, with resulting changes to the energy balance between the atmo-
sphere and ocean.
Most of the scientific community's insight into potential "global warming"
scenarios comes from large computer simulations called general circulation
models (GCMs). The GCMs are quite sophisticated but often suffer from a
lack of experimental input data and input physics from many remote regions
throughout the world, particularly the Arctic. AOS-94 offered a unique op-
portunity to deploy state-of-the-art atmospheric radiation budget measure-
ment apparatus in the high Arctic and to allow them to gather data continu-
ously for several weeks. This was the first high-Arctic expedition to deploy
these advanced optical instruments, and the large resulting data set should
enable better representation of the Arctic atmosphere in the GCMs.
The California Space Institute project consisted of three major compo-
nents, all deployed aboard the Polar Sea. The first was a battery of broad-band
solar and infrared flux radiometers mounted above the pilothouse. Three Ep-
pley Laboratory radiometers measured downwelling short-wave (0.282.8 m),
ing the Arctic Ocean surface. A Biospherical Instruments radiometer measured
downwelling solar ultraviolet and visible radiation at 0.308, 0.320 and 0.380 m,
as well as radiation in the intervals 0.5800.680 m (to match a satellite radiom-
Dan Lubin is with the California Space Institute at the Scripps Institution of Oceanography in La Jolla, Califor-
nia, U.S.A. Robert Whritner is with the Arctic and Antarctic Research Center at the Scripps Institution of
Oceanography in La Jolla, California, U.S.A.
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