Winds and Cloud Heights (Vaughn, Campbell)
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A program which calculates geometric cloud heights from shadows is nearly
ready for general distribution to RAMSDIS sites. The program requires
human input, so is most useful for special case studies.
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An asynchronous stereo/wind analysis program is under continuing development.
In this quarter, a mixture of GOES and AVHRR data was used to derive heights
matching the GOES 8 plus GOES 9 results. Also, favorable comparisons
have been made with the NESDIS automatic cloud motion analysis. The
program is still in the demonstration phase. Analysis with
4 km, channel 4 data seems to be working, since its results match very
well with the VIS 1 km data analysis. Next we need to test the combination
of GOES 4 km IR and AVHRR 4 km IR data (GAC). The following two figures
are of interest (Click on images for full-size imagery):
Figure 1. GOES 9 visible image with cloud heights and winds derived
using AVHRR LAC data. GOES data were available at 20:45, 21:00, 21:30
and AVHRR at 21:20. The numbers represent the height of the clouds
or land in hectometers (98 = 9.8 km). The height of the ground should
be subtracted from the analyzed height.
Figure 2. GOES 9 IR image with cloud heights/winds derived with
the use of AVHRR LAC data. The 1 km LAC data were remapped into the
GOES 4 km IR data file. After adjusting for the analyzed height of
the ground, cloud heights match results from the 1 km visible analysis
to within 0.5 km.
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For the stereo analysis a REMAP program is required. The McIDAS
REMAP program has been modified to allow 2-byte output and may be of general
interest to the McIDAS community.
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