A summer beach day in Oregon often involves a cool, gray blanket of fog that not only shapes the experience of beachgoers, but also the coastal and inland environment.
Now, commercially available surfing webcams are helping scientists measure Oregon's coastal fog, according to a study from the University of California, Davis in collaboration with the USDA Forest Service.
The study, published in the journal Agricultural and Forest Meteorology, is the first to research the spatial variability of fog along the Oregon coastline using webcams and airport weather metrics.
"Fog is a cloud that literally touches people's lives and also impacts ecosystem health, particularly during the Oregon and California summertime," said lead author Sonya Rauschenbach, a graduate student in Associate Professor Adele Igel's Cloud Physics Group at UC Davis. "It's a direct input into the water system here."
Climate change and coastal fog
Climate change is expected to change the frequency of coastal fog in complex ways, with implications for the local environment and its people, transportation networks, economy and culture. To better anticipate those changes, it is important to understand the spatial and seasonal patterns of fog, particularly during the summer, when fog is a key source of moisture.
Fog is a cloud that literally touches people's lives." - Sonya Rauschenbach, UC Davis
Fog is typically measured via satellite, which offers high-resolution imagery but does not differentiate between fog and low clouds. Instruments that detect fog precisely are expensive, so they are rarely used. As an alternative, the authors wondered whether webcams commonly used by the surfing community would be able to accurately detect fog.
During the summers of 2022 to 2024, the researchers collected daytime images from five commercially available surfing webcams, with permission from the owners.
Sites included Agate Beach, Otter Rock, Pacific City, Lincoln City and Cannon Beach. The authors also analyzed a long-term database of images at Yaquina Head from Oregon State University (OSU). Together, the study area covered 93 miles of Oregon's coast.
They compared their analysis with surface weather metrics from the Newport Municipal Airport, where a visibility sensor measures fog.
The frequency of fog
The results show patterns of patchy fog across the sites, but rarely all at once. Typically, fog was present at only one site at a time, shifting rapidly over short distances.
"I thought I kind of knew its spatial patterns, but I've been surprised by how low the correlation was between some sites," said coauthor John Kim, a biological research scientist with the USDA Forest Service. "I think that's helpful to know for the beach-going public and deepens the mystery for fog scientists."
Fog is defined as visibility lower than 1 kilometer, or about a half a mile. The cameras were able to generally suggest the presence of fog at one site versus another, but they could not precisely measure visibility levels.
"A key part of our paper was simply answering, 'Can we do this?'" Rauschenbach said. "Can we use publicly available cameras to qualitatively detect fog? We were able to, with some limitations."
The study found that airport measurements were a good indication of average monthly fog frequency along the coast. However, surface weather conditions at the airport were not sufficient to detect fog in real time at any specific location along the coast. This highlights the need for onsite, real-time fog measurements.
The study's additional coauthors include Ian Faloona and Kyaw Tha Paw U from UC Davis, Alex Dye from OSU and the Department of Oregon State Fire Marshal, and R. Cotton Rockwood and Christopher Still from OSU.
The study was funded by the USDA Forest Service Western Wildland Environmental Threat Assessment Center, USDA National Institute of Food and Agriculture, Earth Science Information Partners and Oak Ridge Institute for Science and Education.
