CloudSat completed an eye overpass of Super Typhoon Atsani in the West Pacific on August 19, 2015 at 0327 UTC. Typhoon Atsani contained estimated maximum winds of 130 knots (150 mph) and minimum pressure of 926 hPa (equivalent to a category 4 strength hurricane). Typhoon Atsani strengthened into a Super Typhoon August 19, 2015 @ 0000 UTC. CloudSat overpassed Super Typhoon Atsani shortly after the intensification into a Super Typhoon.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured the infrared (IR) image taken a few minutes before the CloudSat overpass (the blue line A-> B on Figures 1 and 2). Figure 2 from AQUA, 4km remapped and color enhanced infrared (IR) imagery reveals the cold cloud tops surrounding the center of the storm. Figure 3 depicts the CloudSat 1B-CPR imagery of the overpass. Figure 4 is a time lapsed animation combining Multifunctional Transport Satellite (MTSAT) imagery and the CloudSat overpass. Figure 5 combines MTSAT and CloudSat imagery into a 2D image.
CloudSat's 94 GHz cloud profiling radar (CPR), overpassed just to the west of the large eye of Atsani intercepting a portion of the eyewall. The CloudSat overpass (Figure 3) reveals the sloping nature of the eyewall and the very heavy rainfall associated with this area (where the CloudSat radar signal dips and becomes very narrow). The CloudSat CPR signal attenuates in very heavy rainfall when cloud droplets become larger than 3 mm and dampens the strength of the CPR signal.
The overpass also highlights the outward sloping areas of reflectivity just outside the eyewall area and the deep convective cloud tops in the areas northwest and southeast of the eye. Areas underneath the cirrus canopy (moats) reveal areas of limited and/or light precipitation with most of the convection on the southern side of the storm. Cloud top heights average 16 km. Areas of pink and red designate larger amounts of liquid and ice whereas areas of light blue indicate smaller cloud droplets. The cirrus canopy extends much farther outward over the southern section of the storm.
Figure 1. MODIS imagery with CloudSat track (blue line A->B) of Typhoon Atsani.
Figure 2. 4km Remapped Color Enhanced Infrared Imagery (courtesy RAMMB) with CloudSat track in red.
Figure 3. CloudSat 1B-CPR imagery of Typhoon Atsani.