Hurricane High Tech: Tracking Irene

Tropical systems (warm-core lows) like Irene thrive in warm water environments like we’re seeing off the Carolina coastline. We know that regions with warm sea surface temperatures (SSTs) and weak upper level winds can lead to rapid strengthening of tropical system into hurricanes. In recent years satellite technology like TRMM (Tropical Rainfall Measuring Mission) allows us to track and analyze these systems in ways not thought possible before. In the ‘old days’ we’d look at satellite imagery from space and see beautiful cloud textures, but otherwise very little of what was happening ‘beneath the clouds.’ This now has changed with TRMM being able to scan through the upper cloud layers to yield a “CAT-scan” like view inside the storm. Unique to this technology is being able to identify “hot towers” or overshooting cloud top features associated with strong cumulonimbus thunderstorm towers — these features have been identified to increase shortly before the hurricane’s wind speeds increase hours later and central pressure drops accordingly. Another great feature is the ‘space-based’ radar scans that allow us to get rainfall estimates while the storm is still well out over the ocean. Land-based radar systems really have only helped as storms near landfall. TRMM’s space-based radar lets us anticipate regions of heaviest rainfall and prepare better forecasting for potential flooding down the road. Much of the technology now being employed in tropical meteorology has been designed and developed here in the Silicon Valley. This will hopefully go a long way to helping create more accurate rainfall, and wind field strength forecasts down the road.