Hurricane Frances Rain Towers

NASA's TRMM spacecraft allows us to look under Hurricane Frances' clouds to see the rain structure. Spikes in the rain structure known as 'Hot Towers' indicate storm intensity. The 'hot towers' which refers to the tall cumulonimbus, has been seen as one of the mechanisms by which the intensity of a tropical cyclone is maintained. Because of the size (1-5 km) and short duration (30 minute to 2 hours) of these hot towers, studies of these events have been limited to descriptive studies from aircraft observations, although a few have attempted to use the presence of hot towers in a predictive capacity. Before TRMM, no data set exists that can show globally and definitively the presence of these hot towers in cyclone systems. Aircraft radar studies of individual storms lack global coverage. Global microwave or Infrared sensor observations do not provide the needed spatial resolution. With a ground resolution of 5 km, the TRMM Precipitation Radar provided the needed data set for examining the predictive value of hot towers in cyclone intensification.