Cooperative Atmospheric Surface Exchange Study 1999

Project Description
The concept of CASES-99 was borne out of a scientific interest in
stable atmospheric conditions. The stable atmosphere, due to its
generally weak or intermittent turbulence (`bursting'), is the source
of a number of outstanding problems in atmospheric science,
agricultural meteorology, and signal propagation, amongothers. As
such, CASES-99 focussed it's Intense Observing Periods during the
clear sky, light near-surface wind, nocturnal boundary layer (NBL)
conditions, which are conducive to stable (Ri > 0.25) and very stable
conditions (Ri > 1.0). There are also significant components that will
study the transition periods (from daytime, unstable to nighttime,
stable conditions and vice-versa).

The experimental period was from October 1-31, 1999 near Leon, Kansas
(50 km) east of Wichita, Kansas with a 3 day intercomparison and
instrument testing period from September 27-30. This area was chosen
for CASES-99 due to its relative lack of obstacles, relatively flat
terrain (average slopes are 0.5 degrees), and reasonable access to
power and phone lines. A large number of instrumentswill be deployed
in a an area 4.8 x 3.2 km, to capture stable NBL heterogeneity, with
some outlying instrumentation. These instruments include a heavily
instrumented 60 m tower, numerous 10 m towers (many with flux
measurements), multiple radars, lidars, scintillometers, tethersondes,
rawinsondes and research aircraft. See the experimental design for

CASES-99 was a very successful experiment and essentially all of our
scientific goals can be addressed with the data taken. The data is
stored for public use (no password protection) in the UCAR JOSS
CASES-99 Data Archive . The Archive contains quality-controlled data
complete with timestamps in UTC and descriptions of the data therein,
listed by data platform.

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