PREDICT CIMSS also Focusing on Hot Towers
Posted by JAC on 7/30/2010, 6:45 pm
http://cimss.ssec.wisc.edu/tropic2/predict/overshooting_tops/Animation.html

Recent research has indicated that the presence of "vortical" hot towers in pre-genesis tropical cyclones increases a concentrated vertical component of vorticity and therefore increases the likelihood of tropical cyclone development.

"Vortical" hot towers are defined as updrafts extending to at least the tropopause (A Vortical Hot Tower Route to Tropical Cyclogenesis, Montgomery et al, 2006).

This research looks to employ an objective satellite-based overshooting top detection algorithm to average the number of overshooting tops experienced by an area of potential tropical cyclogenesis.

http://cimss.ssec.wisc.edu/tropic2/predict/overshooting_tops/OT_algorithm_explanation.html

However, instead of using a 6-hour tropopause forecasts, a greater temperature difference between the potential OT and surrounding anvil was used, with potential OTs being colder than 215K.

Using this method, potential areas of topical cyclogenesis from 2009 were analyzed, comparing the average number of overshooting tops per day with the vertical component of vorticity at 40W.

Results can be seen at the bottom of the page.

Presently, these are the running count and average number of overshooting tops for the areas of potential tropical cyclogenesis in the Atlantic Ocean from the time of identification to the present.






Inital research was conducted using UKMet 700 hPa forecast location and vertical component of vorticity at a temporal resolution of 6 hours.

Therefore invest location and vertical component of vorticity was linearly extrapolated for each satellite scan between the forecast times.

The average number of overshooting tops experienced per day from the time on invest idenfication to 40W compared with the invest vertical component of vorticity at 40W can be seen below.

The correlation of 0.755 does not include Hurricane Bill, since Hurricane Bill was a hurricane when crossing 40W whereas the other invests (Hurricane Fred and TD 8) were not (both lost strength before 40W). When including Hurricane Bill, the correlation drops to 0.628.









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IAKE - A Parameter Useful to Track Genesis - JAC, 7/30/2010, 1:41 pm
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