Morphology and microphysics of cloud particle of Jumping Cirrus clouds measured by Himawari-8

Abstract:

Jumping Cirrus clouds (JC) are a type of cirrus clouds that jump up 1-2 km from the anvil top and disappear after floating (Fujita, 1974). JC would hydrate the lower stratosphere when the cloud top of the anvil clouds JC generated reach the tropopause.

Seguchi et al. (2019) reported JC’s characteristics, such as a jumping height and a vertical jumping speed of JC, by using the ground-based cameras whose spatiotemporal resolutions are about 10 m and 15 s, respectively. Most of them are similar to the results of numerical simulation by Wang et al. (2011). The observed JC’s width is, however, several times smaller than that of the simulation. This would be because the ground-based cameras can only observe JC within a few kilometers from the edge of anvil since the anvil clouds between the cameras and JC disturb the line of sight of the cameras.

We succeeded in finding six JC by using the visible images of the meteorological geostationary satellite Himawari-8, whose temporal and horizontal resolutions are 2.5 minutes around Japan and 0.5 km at a wavelength of 0.64 μm, respectively. The six JC generated from the same consecutive convective cloud cluster within four hours. Note that the satellite can measure the whole anvil clouds and JC.

The averaged width and length of the six JC were 10 km and 23 km, respectively, and the averaged lifetime was 35 minutes, where the lifetime is defined as a period from the time of jumping to the time that we could not distinguish JC from the surrounding anvil clouds.

We will show the morphology of JC and the microphysics of JC, such as number concentration and mode size, by using the ray-tracing method.