Ground-based observations of cumulus entrainment rates in continental and maritime convection

A ground-based remote sensing algorithm capable of retrieving entrainment rates in cumulus clouds has been developed. This algorithm, called the Entrainment Rate In Cumulus Algorithm (ERICA), uses high-temporal resolution profiles of temperature, moisture, and radar reflectivity and velocity from ground-based instruments as inputs into a Gauss-Newton optimal estimation scheme. The observations and a first guess of the entrainment rate are ingested by the Explicit Mixing Parcel Model (EMPM), a one dimensional cloud parcel model that includes finite rate mixing and explicit droplet microphysics. EMPM then calculates the effective radius and liquid water path of the cloud and the results are compared to ground-based observations of the same, and the entrainment rate guess is adjusted iteratively until the results converge. ERICA was initially developed for the retrieval of entrainment rates at the Southern Great Plains (SGP) site of the Atmospheric Radiation Measurement (ARM) program. Initial results show a mean entrainment rate for spring and summer cumuli of 1.06 km^-1. Since then, it has been extended for use at the Tropical Western pacific (TWP) ARM site, which features deeper and more vigorous convection than the SGP site. This enables the intercomparison of entrainment rates between two different convective regimes over substantially longer times scales than afforded by in situ observations. Results from both sites and intercomparisons between the two will be presented.