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Daily variability of California coastal low cloudiness: A balancing act between stability and subsidence

TitleDaily variability of California coastal low cloudiness: A balancing act between stability and subsidence
Publication TypeJournal Article
Year of Publication2017
AuthorsClemesha R.ES, Gershunov A, Iacobellis S.F, Cayan DR
JournalGeophysical Research Letters
Date Published2017/04
Type of ArticleArticle
ISBN Number0094-8276
Accession NumberWOS:000400186500042
Keywordscoastal california; coastal climate; coastal fog; fog; imagery; impact; layer; low cloud; marine; pacific; reanalysis; rotation; sea-surface temperature; summer low cloudiness; synoptic variability

We examine mechanisms driving daily variability of summer coastal low cloudiness (CLC) along the California coast. Daily CLC is derived from a satellite record from 1996 to 2014. Atmospheric rather than oceanic processes are mostly responsible for daily fluctuations in vertical stability that dictate short-period variation in CLC structure. Daily CLC anomalies are most strongly correlated to lower tropospheric stability anomalies to the north. The spatially offset nature of the cloud-stability relationship is a result of the balancing act that affects low cloudiness wherein subsidence drives increased stability, which promotes cloudiness, but too much subsidence limits cloudiness. Lay explanations claim that high inland temperatures pull in CLC, but such a process presumably would have the high temperatures directly inland. Rather, we find that the spatially offset associations between CLC and atmospheric circulation result in positive correlations between CLC and inland surface temperature anomalies to the north.

Low clouds over San Diego in mid-2017

Low clouds over San Diego in mid-2017

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