In-Cloud Supersaturation Derived from CCN Measurements
The Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) included a targeted aircraft campaign off the coast of Monterey, California, in July and August 2011. The Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft made measurements of aerosol and cloud properties targeting three types of emissions in the stratocumulus-rich northeastern Pacific: smoke emissions from the R/V Point Sur, salt aerosol released by the Twin Otter, and emissions from cargo ships. In-cloud measurements sampled cloud residuals from behind a counterflow virtual impactor (CVI.) A cloud condensation nuclei (CCN) spectrometer (a Droplet Measurement Technologies Continuous Flow Streamwise Thermal Gradient Chamber operating in Scanning Flow CCN Analysis mode) aboard the Twin Otter provided CCN spectra once every forty seconds and are used to derive ambient supersaturation. We present the effects of aerosol perturbations on cloud droplet properties and in-cloud supersaturation for a variety of environments sampled during E-PEACE.