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Cooperative Institute for Meteorological Satellite Studies / University of Wisconsin-Madison
Tropical Cyclones

Wavetrak mosaics are intended to be useful for tracking features such as tropical cyclones, tropical waves, and system interactions in tropical latitudes. There are 2 types of Wavetrak mosaics generated on a real-time basis in 6 hourly cycles:
Infrared satellite imagery with overlaid satellite derived low-level cloud drift winds:
This product is generated utilizing geostationary infrared (11µm) satellite imagery and overlaid satellite derived low-level cloud-drift winds. The cloud-drift winds are created by a combination of both visible and infrared imagery. In order to track the low- level circulations associated with tropical waves, only cloud-drift winds between 600-925 hPa are utilized in the mosaics.
850 hPa relative vorticity:
This product depicts the low-level (850 hPa or ~5,000 ft) vorticity that is often associated with tropical waves, tropical cyclones, and synoptic scale features. NOGAPS model data is used as a first guess background field to stabilize each analysis. Satellite derived cloud-drift winds are then applied to this field, utilizing a recursive filtering technique. This technique allows for the satellite data to dominate the relative vorticity analysis. Values are color-enhanced and scaled to accommodate the circulation reversal that exists between the northern and southern hemispheres.
• The Atlantic sectors of Wavetrak are covered by the GOES-West, GOES-East, METEOSAT-8 and METEOSAT-5 satellites.
• The Pacific sectors of Wavetrak are comprised of coverage by the METEOSAT-5, MTSAT-1R, and GOES-West satellites.