A climatology of cold pools distinct from background turbulence at the Eastern North Atlantic observations site

Abstract. We develop an algorithm to identify cold pools at the DOE’s Eastern North Atlantic (ENA) site on Graciosa Island and examine the statistics of retrieved cold pools for the entire observational record from late 2016 to 2023. The retrieval strategy relies on leveraging above-background bivariate deviations in near-surface temperature and water vapor mixing ratio from the ENA station time series. Cold pools at ENA tend to be weak with a prominent annual cycle peaking in the cooler months and caused by reductions in the background turbulence during those months. Often, surface rain events are not associated with cold pools due to a combination of factors including but not limited to high background turbulence, high relative humidity, and low rain rate. The retrieval correctly identifies cold pools that are not associated with observed surface rain at the met station. Understanding the factors that lead to the formation of weak cold pools will lead to a greater understanding of the dynamics of the marine boundary layer at ENA and how those dynamics feed back to the cloud morphological structures.