Abstract:
The First ISCCP Regional Experiments have been designed to improve
data products and cloud/radiation parameterizations used in general
circulation models (GCMs). Specifically, the goals of FIRE are (1) to
seek the basic understanding of the interaction of physical processes
in determining life cycles of cirrus and marine stratocumulus systems
and the radiative properties of these clouds during
... their life cycles
and (2) to investigate the interrelationships between the ISCCP data,
GCM parameterizations, and higher space and time resolution cloud
data.
To-date, four intensive field-observation periods were planned and
executed: a cirrus IFO (October 13 - November 2, 1986); a marine
stratocumulus IFO off the southwestern coast of California (June 29 -
July 20, 1987) a second cirrus IFO in southeastern Kansas (November 13
- December 7, 1991); and a second marine stratocumulus IFO in the
eastern North Atlantic Ocean (June 1 - June 28, 1992). Each mission
combined coordinated satellite, airborne, and surface observations
with modeling studies to investigate the cloud properties and physical
processes of the cloud system.
The Belfort Laser Ceilometer was operated during FIRE ASTEX on Porto
Santo, Madeira. It utilized a 20 watt near-infrared Gallium-Arsenide
laser operating at a wavelength of 0.91 microns to detect cloud base
height. It employed 1024 range gates which yield a vertical
resolution of 25 feet up to a maximum range of 25,600 feet. The
fields of view of the transmitter and receiver are approximately 1
degree.
The ceilometer used a measured "noise level" to determine a "count"
(-1,0,1) which is then summed for each gate. This "histogram" is the
basic output from which the cloud base height is estimated. 
