September 10, 2004:
In the wake of Hurricane Frances that hit the Florida Peninsula the weekend of September 4, 2004, Hurricane Ivan has formed in the Tropical Atlantic and is approaching the Gulf of Mexico with category 4 strength (See NOAA's Tropical Prediction Center). The MODIS instrument on board of NASA's Terra satellite captured this image of Ivan as it was north of Venezuela at 3:10 am UTC on September 9, Figure 1. The image shows brightness temperatures retrieved from the MODIS infrared channel 31 (11µm). The eye of the Hurricane is clearly visible in the center of the whirl thanks to the sharp contrast between the cloud top temperatures and the eye. In fact, the eye is so well formed that the infrared channel sees through it, all the way down to the ocean surface (red pixels in the eye). Ivan is a well-organized compact Hurricane, with a core of about 200-300km. It is likely that this is facilitated not only by the warm ocean surface waters, but also by the upper level high pressure sitting on top of the hurricane. A possible indicator of that are the clock-wise cold "plumes" of very light and humid air that are pouring in from the strong convective cells - the black extremely cold spots in the bottom part of the image. If they invoke an image of smoke coming out from chimneys, that association is quite close to reality. MODIS radiances data and visualization tools are available from the NASA Goddard Earth Sciences Data and Information Services Center .

Figure 1. Hurricane Ivan Brightness Temperature measured by

MODIS/Terra at 11µm on September 10, 2004 at 3:10am.

September 14, 2004:
To monitor hurricane rainfall is a challenging task, especially over the vast and data sparse oceans. The Tropical Rainfall Measuring Mission (TRMM) provides a unique way to measure rainfall from space. With merged data from TRMM and other satellites, it is possible to monitor rainfall between the latitudes of 50 S to 50 N every three hours. Figures 1 and 2 show rain from Ivan accumulated over two time periods. The first one is from midnight to 3 am, September 14, as Ivan cleared the western coast of Cuba, still a Category 4 storm. The second one is from September 10 to 14, as a Category 5 Ivan brought widespread destruction across the Caribbean.

Figure 1. Rainfall accumulation from

Hurricane Ivan between September 10

and September 14, 2004.

Figure 2. Rainfall accumulation from

Hurricane Ivan on September 14, 2004

between 00:00 and 03:00 EST.

View a GIF animation of Hurricane Ivan's rainfall

For the latest plots and animation, please visit:
http://disc2.nascom.nasa.gov/Giovanni/tovas/realtime.3B42RT.shtml