VOCALS: Cloud Remote Sensing in Support of VOCAL-REx: Linking Cloud Optical Properties to Aerosol and Precipitation Variability

University Of Miami, Coral Gables FL

Investigators

Abstract

The sparsely observed Southeast Pacific Ocean is covered by the world's largest subtropical sheet of stratocumulus clouds. Climate models poorly simulate these clouds, with consequences for the global climate sensitivity and for model simulations of how atmospheric particles affect the climate. While these simulations are improving, better model treatments of clouds and particles are limited by gaps in the understanding of key physical processes, such as the interactions of clouds, aerosols, and drizzle. The observations and analyses in this project are contributions to VOCALS-REx, the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment, a program of field measurements, analysis, and modeling, intended to address these gaps. (VAMOS is an international science project, the Variability of the American Monsoon System.) This project focuses on cloud remote sensing that links cloud optical properties to the underlying aerosol and drizzle variability. Cloud liquid water paths (LWPs) will be retrieved using data from a microwave radiometer deployed on the NSF C-130 aircraft. These measurements are an essential part of VOCALS-REx. Cloud LWPs are arguably the most important parameter for low clouds over the ocean: they affect how much sunlight the clouds reflect back to space, and they are crucial to identifying the effects of particles on clouds and precipitation. Cloud LWP is the variable most commonly compared between models and observations. This microwave radiometer will provide LWP retrievals of higher accuracy than has previously been possible for low-latitude stratocumulus clouds. Broader impacts of this work are in supporting the PhD thesis work of a Chilean graduate student. Zuidema and the graduate student will participate in the "Windows to the Universe" VOCALS education and outreach program, and Zuidema will engage with high-school science classes at her alma mater in Urbana, Illinois, which has a predominantly lower-income student population.