The variability of the tropical ice cloud properties from ground-based radar-lidar observations over Darwin, Australia

Description

In the present paper the statistical properties of non-precipitating tropical ice clouds (deep ice anvils resulting from deep convection and cirrus clouds) over Darwin, Northern Australia, are characterized using ground-based radar-lidar observations from the ARM Climate Research Facility. The ice cloud properties analyzed are the frequency of ice cloud occurrence, the morphological properties (cloud-top height, base height, and thickness), the microphysical and radiative properties (ice water content, visible extinction, effective radius, terminal fall speed, and concentration), and the internal cloud dynamics (in-cloud vertical air velocity). The variability of these tropical ice cloud properties is then studied as a function of different large-scale environmental conditions: the large-scale cloud regimes derived from the International Satellite Cloud Climatology Project (ISCCP), the amplitude and phase of the Madden-Julian Oscillation (MJO), and the large-scale atmospheric regime as derived from a long-term record of radiosonde observations over Darwin. The rationale for characterizing this variability is to provide an observational basis to which model outputs can be compared for the different regimes or large-scale characteristics and from which new parameterizations including the large-scale context can be derived.