College - Author 1
College of Science and Mathematics
Department - Author 1
Biological Sciences Department
Degree Name - Author 1
BS in Marine Sciences
Ryan K. Walter, College of Science and Mathematics, Physics Department
Temperature variability in the nearshore coastal ocean influences various biological processes and can drive changes in biodiversity and habitat range. Despite recent progress, there are still significant gaps in the understanding of drivers of temperature variability in upwelling bays, particularly at higher frequencies. In this study, we analyzed a decade of nearshore temperature measurements both inside and outside a small coastal embayment located in central California [San Luis Obispo (SLO) bay], as well as temperature data from satellites, to characterize rapid warming events. We found that rapid warming events, defined using rates of temperature change across different thresholds, occurred more frequently and with greater magnitudes during the major upwelling season (April to September). Warming events occurred more frequently inside the bay compared to outside, and warmer temperatures were sustained within the bay as a result of an upwelling shadow system, due to the local coastline orientation and topography. The largest warming events typically occurred during a regional upwelling wind relaxation period. The exact source of the warm waters requires further research, but possible sources include the large-scale advection of offshore waters during relaxation events, the poleward propagation of warm waters as a buoyant plume front during relaxation events, and/or eddies and filaments generated by submesoscale instabilities. These rapid warming events could have a significant influence on the physiology of nearshore organisms and the connectivity of larvae. Further investigation into how organisms and ecosystems respond to these rapid warming events may provide insight into how they will respond to climate-driven ocean warming, with important conservation implications.