Rainfall Microphysics and Instrument Measurement Assessments via Rainfall Simulators

This study presents investigations on rainfall microphysical processes and ground-based rainfall instrument measurements through laboratory rainfall simulations with careful considerations for in-situ observations and validations.  Controlled laboratory rainfall experimentation has a pivotal role in systematic investigations to deepen our understanding of rainfall microphysical processes and the development, calibration, and assessment of rainfall instruments.  In the rainfall and related investigations in the PI’s laboratory over the past nearly two decades, we have utilized a variety of laboratory rainfall simulation setups, each featuring customized drop generators for the application, that were designed to address the specific aspects and objectives of the targeted research.  Here we will present our select experimental investigations on raindrop morphodynamics (shape and fall speed) and collisions as well as assessments of the OTT Parsivel² disdrometer and OTT Pluvio² rain gauge measurements.  Raindrop morphodynamics and collisions are of importance for various applications, including radar rainfall retrievals and hydrological modeling.  Parsivel² and Pluvio² are widely used ground-based instruments to monitor various precipitation quantities (e.g. raindrop size distribution, fall speed, and rainfall intensity, amount, and kinetic energy) that are of importance for a variety of rainfall- and water resources-related applications, including ground validation and soil erosion studies.  This material is based upon work supported by the National Science Foundation under Grants No. AGS-1741250 to the first author (FYT).