Anvil-radiation diurnal interaction: Shortwave radiative-heating destabilization driving the diurnal variation of convective anvil outflow and its modulation on the radiative cancellation

Abstract. The behavior of convection producing the anvil is neither well derived from current available observations nor well represented in models. In this work, a novel convective cloud data product is designed to capture the convective anvil outflow. Convective organizations and life stages are derived from the images of infrared brightness temperature (BT) of geostationary (GEO) satellites based on a variable-BT segment tracking algorithm, which brings the possibility for quantifying the convective anvil outflow. Vertical structures of convection are measured by sensors of the A-Train Constellation, which provides the cross section of convective outflow. Here, GEO-based convective tracking and A-Train-detected cloud vertical profiles are combined to develop a novel comprehensive GEO-A-Train merged (GATM) convective cloud data product for investigating the process of convective anvil outflow.

On the basis of this novel Lagrangian-view GATM data, the anvil production for mesoscale convective systems (MCSs) can be quantified. The results show that daytime MCSs can produce more anvil clouds than nighttime MCSs. During the daytime, shortwave radiative heating destabilizes the MCS top and invigorates the top-heavy circulation to promote the anvil outflow, whereas during the nighttime longwave radiative cooling stabilizes the MCS top and weakens the circulation to hinder the anvil outflow. Moreover, approximately 11 W m^-2 for cloud radiative effects are modulated by the diurnal variation of convective outflow. Overall, this work presents the observed anvil-radiation diurnal interaction process: radiative heating determines the diurnal variation of anvil outflow; in turn, the diurnal variation of anvil outflow determines the Earth radiative budget.