Passive Fog Water Measurements Along the Northern California Coast During the Summer of 2014

Abstract:

As a part of the UC Santa Cruz, Moss Landing Marine Lab, and California State University Monterey Bay multi-year effort to track the cycling of methyl mercury compounds through fog deposition, researchers have deployed 1.00 m² standard passive fog collectors based on the Schemenauer design at 13 locations throughout Northern California during the summer of 2014. These devices consist of a 1.00 m² mesh that collects tiny fog water droplets that coalesce, fall into a trough and whose volume is recorded by a tipping bucket rain gauge at 15-minute intervals. These data provide an estimate of the fog density and a quantitative measurement of the amount of liquid water available from each fog event.

Several of these sites were deployed in conjunction with active strand collectors based on Colorado State University's Caltech Active Strand Cloudwater Collector (CASCC) design which are used to collect clean water samples for the detection of mercury. This presentation will highlight the spatial and temporal variability observed within the data sets during this first summer (2014) of active collection. Of particular and significant note is the variability of the fog in relationship to distance from the coast as well as the latitudinal variability.

We note that the observations coupled with accompanying meteorological measurements can potentially help to provide estimates of the potential flux of moisture available from fog events to ecosystem processes during the otherwise dry season along the California coast.