One of the most common themes in popular discourse and media discussions about fog in California relate to climate change: Is fog going away? or How will fog change as the planet warms? We still do not know whether fog will increase, decrease, or stay the same as the climate warms. Furthermore, the research community still has not fully scrutinized and mechanistically explained the observed changes and variability in the growing observational records of FLCC and associated key meteorological variables (e.g. temperature inversion characteristics). To address this gap, and to set-up success for our final research question, we will first answer the basic questions: has fog already started to go away along the California coast, and if so, where, and why?

Specifically the first two core science questions are:  

1. How has coastal FLCC frequency, seasonality, and vertical structure varied over decadal to multidecadal scales, and how do these changes relate to large-scale climate phenomena? 

2. How has the spatial distribution, inland penetration, and diurnal pattern of coastal FLCC changed over the recent three decades, and what mechanisms control these spatial-temporal dynamics? 

The outputs from the historical investigations will be necessary to address the third core science scientific question: 

3. Given the historical relationships and spatial-temporal dynamics identified, how well can the sixth Coupled Model Intercomparison Project (CMIP6) model fields be utilized to represent FLCC, and what can be confidently predicted about future coastal fog conditions?