Characteristics of a Jumping Cirrus Retrieved From Rapid Scans by Himawari‐8

Abstract

AbstractA jumping cirrus (JC) is a cloud that forms a few kilometers above an anvil cloud downwind of an overshooting top (OT). A JC transports water vapor from the troposphere into the stratosphere, where water vapor is an important greenhouse gas. However, the microphysics of JC has not been explored thus far. Herein, 2.5‐min rapid scan images obtained from the geostationary weather satellite Himawari‐8 were analyzed for JC observations. A dark plume was observed to appear suddenly above an anvil cloud downwind of OTs and moved 1 km upwind within 2.5 min. The brightness temperature of the plume showed that it overlaid the anvil cloud. These characteristics matched those of a JC. The reflectivity of the assumed JC at a wavelength of 0.64 μm was 0.62, whereas that of the anvil cloud on the sunny side of the JC was 1.02. The measured reflectivities were compared to those simulated using ray tracing to retrieve the microphysics of the JC. The results indicated that dark reflectivity occurred because the JC was isolated above the anvil cloud, and bright reflectivity occurred because the anvil was illuminated by the sun and scattered light from the JC. The retrieved effective radius and ice water content of the JC were 23.4–28.0 μm and 0.12–0.15 g m−3, respectively. The JC appeared to transport 10 × 103 t of ice water above deep convection within 10 min. We applied the results to analyzing the best satellite geometry for detecting and measuring JC.