Peering Inside Tropical Storm Aletta

Tropical Storm Aletta formed on May 15, 2012, becoming the first tropical cyclone to be tracked by the National Hurricane Center during the 2012 season. A Northeast Pacific storm, Aletta is south of the Baja Peninsula and heading west with no threat to the mainland. The recently launched Suomi-NPP satellite, operated by NOAA and NASA, flew over the storm on May 15th, providing a glimpse inside the storm. The satellite's ATMS sensor can detect subtle differences in moisture using microwave energy, allowing it to "see" through the cloud tops. Whereas the more commonly used infrared satellite imagery from same time show high clouds tops, but an otherwise unorganized system, ATMS microwave imagery shows an area of circulation in the middle of the storm, indicative of a cyclone. The ATMS is an advancement over the previous AMSU microwave sensors that NOAA has flown on its polar-orbiting satellites, providing higher resolution, more channels, and fewer gaps between orbits, allowing meteorologists to more accurately dissect severe weather systems.

In this image, areas of higher "brightness temperature" correspond with areas of high moisture in the atmosphere. The low moisture area associated with the center of circulation (which may later form into an "eye") can be seen as the dark circular feature. The "no data" flanking both sides is due to the fact that Suomi-NPP orbits around the poles, collecting data in swaths, and those areas were outside of that particular coverage swath. Data from Suomi-NPP is still undergoing quality assurance processes and are not yet operational products. Suomi-NPP was launched last year in preparation for NOAA's next generation JPSS series of satellites.

Courtesy of NOAA Environmental Visualization Laboratory