For CRSPE, the VIL was located near Pine Bluff,
Wisconsin (43.06
N
Latitude and 270.30
E Longitude) while the HSRL was located to the east in
Madison, Wisconsin (43.08
N Latitude and 270.58
E Longitude). The
HSRL was located a distance of 24 km from the VIL at an azimuth of 
(1.26 km North and 23.97 km East of the VIL). One of the VIL
scan planes was aligned over the position of the HSRL viewing the same
cirrus clouds as the HSRL. In relation to Pine Bluff, Wisconsin, the VAS
was situated at a zenith angle of 52.90
, an azimuth angle of 244.58
,
and a distance of 38017.73 km. The time periods of the experiment under
investigation are from 18:07 to 19:24 GMT and from 19:29 to 21:20 GMT on
December 1, 1989. The separation of the time periods was a result of a
break in the VIL data set. The wind speed, wind direction, temperature,
and pressure at the cirrus cloud heights were determined from coinciding
rawinsonde profiles. There were four rawinsondes launched from
Madison, Wisconsin on December 1, 1989, two of which were used:
18:00 GMT and 21:24 GMT. To create individual profiles between these
times, the rawinsonde data was linearly interpolated between the 18:00
and 21:24 profiles.
Three remote sensing instruments were used to determine the cirrus cloud optical and structural properties. The VIL was used to determine the cirrus cloud structural properties since it viewed the three dimensional cirrus cloud structure. Cirrus cloud cover percentages and horizontal structure functions were calculated from the three dimensional data. The VIL area averaged cirrus cloud structure was compared to the cirrus cloud structure measured by the HSRL. This allowed for the determination of the sampling errors associated with cirrus cloud point measurements. To calculate the cirrus cloud optical properties, all three remote sensing instruments were used. The HSRL was used to calibrate the VIL to determine the visible cirrus cloud optical properties throughout a mesoscale volume. The VAS was used to determine the infrared cirrus cloud optical properties for the same volume.