3D model of Hurricane Irma. Image source: NASA.
3D imagery of Hurricane Irma was captured with NASA’s CloudSat as it approached Puerto Rico in the Atlantic Ocean on September 6th. Hurricane Irma contained estimated maximum sustained winds of 298 km per hour (160 knots) with a minimum pressure of 918 millibars.
NASA launched the CloudSat and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) spacecraft to study the role that clouds and aerosols play in regulating Earth’s weather, climate and air quality.
CloudSat transect over Hurricane Irma. Image source: NASA.
CloudSat transected the eastern edge of Hurricane Irma’s eyewall, revealing details of the storm’s cloud structure beneath its thick canopy of cirrus clouds. The CloudSat Cloud Profiling Radar excels in detecting the organization and placement of cloud layers beneath a storm’s cirrus canopy, which are not readily detected by other satellite sensors.
The CloudSat overpass reveals the inner details beneath the cloud tops of this large system; intense areas of convection with moderate to heavy rainfall (deep red and pink colours), cloud-free areas (moats) in between the inner and outer cloud bands of Hurricane Irma and cloud top heights averaging around 15 to 16 km. Lower values of reflectivity (areas of green and blue) denote smaller-sized ice and water particle sizes typically located at the top of a storm system (in the anvil area).
The Cloud Profiling Radar loses signal at around 5 km in height (in the melting layer) due to water (ice) particles larger than 3 mm in diameter. Moderate to heavy rainfall occurs in these areas where signal weakening is detectable. Smaller cumulus and cumulonimbus cloud types are evident as CloudSat moves farther south, beneath the thick cirrus canopy.
CloudSat and CALIPSO are collecting information about the vertical structure of clouds and aerosols unavailable from other Earth observing satellites. Their data are improving NASA’s models and providing a better understanding of the human impact on the atmosphere.
