Observations of a Diurnal Pulse within the Cirrus Canopy of Typhoon Kong-rey (2018)

In recent years there has been a growing body of work that has documented the existence of diurnal pulses of cloud brightness temperatures within the cirrus canopy of mature tropical cyclones (TCs). The diurnal pulse has been examined primarily using satellites and numerical models, but detailed observations of diurnal pulses are lacking. Questions remain as to if the diurnal pulse is convective coupled or constrained to the cirrus canopy and if its constrained, how the cirrus canopy itself impacts the diurnal cycle of convection in the TC rainbands. During the Propagation of Intraseasonal Tropical Oscillations (PISTON) field campaign, a diurnal pulse in the infrared brightness temperatures seen from Himawari-8, was observed during Typhoon Kong-rey's (2018) rapid intensification. Over a three and a half day timespan where a broad TC cirrus canopy was overhead, detailed observations of Typhoon Kong-rey's outer-core were taken using a suite of instruments including dual-polarimetric radar observations from SEA-POL, 3-hourly soundings, a high spectral resolution lidar (HSRL), and a vertically pointing W-band radar. Using the detailed observations, this study seeks to understand the diurnal variability of convective and stratiform precipitation under a broad TC cirrus canopy and characterize the evolution of the diurnal pulse. This study will provide valuable insight into the complex interactions between radiation and cloud microphysics and used to validate subsequent modeling studies.