To clarify the microphysical structure of mesoscale convective systems (MCSs) over the tropical ocean, we conducted observations of using hydrometeor videosondes (HYVISs) attached GPS sonde and a polarimetric radar of Nagoya University (range of observation: 60 km) in Republic of Palau from May 28 to July 1, 2013. During the observations, 4 HYVISs were intermittently launched into the MCS in June 15. The first HYVIS (H1) launched into the transition region just behind the convective region. The second (H2) and third (H3) HYVISs launched into the stratiform region. This study was analyzed the vertical distribution of type and number of supercooled water and ice particles from these HYVIS images.
It was visually examined the vertical distributions of supercooled water droplets, column type, plate type, and column-with-plates type with a height of 200 m from four HYVIS images. H1 (lanched time: 14:30 LT [Local Time]) showed supercooled water droplets, column type, plate type, and column-with-plates type were observed in the height range of 4.8-7.0 km, 6.2-11.4 km, 5.6-15.2 km, and 6.0-14.8 km, respectively. If we suppose that these ice particles are formed in the convective region, the temperature ranges on the formation of ice particles correspond to those shown in the Kobayashi diagram. H2 (lanched time: 15:44) and H3 (lanched time: 17:05) showed decrease of the top height of detection for each particle type, except for the plate type ice particles in H3. Also, in all particles, the numbers of observed particles were the heaviest in H1 and fewer from H1 to H3.
From these results, the ice particles are presumed to be mainly formed in the convective region according to the temperature range and transported into the stratiform region with gravitational sedimentation.