Satellite Products Specialized GOES Winds

Specialized GOES wind products based on a feature tracking technique were produced by CIMSS as part of the CALJET experiment in 1998. A unique component of this data set is the availability of super-rapid-scan (1-min sampling) GOES images. These data were used to assess the impact of shortening the time between images used in feature tracking. Standard approaches used 30-min between samples, but tests in tropical storms had suggested more frequent sampling could improve areal coverage in regions where cloud features had a shorter lifetime than 30 min. The figures shown here represent the results of this test using a 5-min lag between images for both IR and visible channels. These are compared to results using 30 min lag, and confirm that the areal data coverage increases significantly. Using statistical internal consistency checks it was determined that the optimal time lag was about 5-min. Wind vectors calculated using shorter lags had higher internal variance that resulted from the increased influence of satellite pointing uncertainty as the distance between features decreased, i.e., with shorter time lags. Based on these results, a new GOES scan pattern is being developed that should provide a set of 3 consecutive 5-minute interval images, once every hour around the clock during PACJET over the domain shown here. In addition to the GOES wind products, GOES sounder moisture products (total precipitable water vapor, and cloud-top pressure) will be available at 3-hourly intervals.

UW-CIMSS Automated Tracking Algorithm
GOES-9 VIS Cloud Drift Winds
Using Super Rapid Scan Data (5 Min.)
Full Sized Image

UW-CIMSS Automated Tracking Algorithm
GOES-9 IR Cloud Drift Winds
Using Routinely Available Data (30 Min.)
Full Sized Image

UW-CIMSS Automated Tracking Algorithm
GOES-9 IR Cloud Drift Winds
Using Super Rapid Scan Data (5 Min.)
Full Sized Image

Cloud Top Pressure

Total Precipitable Water Vapor