Available at: https://digitalcommons.calpoly.edu/theses/2665
Date of Award
3-2023
Degree Name
MS in Civil and Environmental Engineering
Department/Program
Civil and Environmental Engineering
College
College of Engineering
Advisor
Stefan Talke
Advisor Department
Civil and Environmental Engineering
Advisor College
College of Engineering
Abstract
There is a growing need to better understand the dynamics of small and medium Mediterranean low-inflow estuaries (LIEs), which is addressed here by characterizing a heat budget and associated heat transfer processes. A one-dimensional deterministic model was developed from the advection-diffusion equation and applied to Morro Bay, CA using 15-minute water property (temperature, salinity, pressure) and meteorological (wind speed and direction, air temperature, relative humidity, air pressure, irradiance) data collected over a two-year period (2020 – 2021). Seasonal variability is observed in meteorological components, water temperature, and salinity. There is strong seasonal variability in head-mouth temperature and salinity differences. Temperature differences peak in summer (daily mean 2.52 ºC, June – Sept.). Daily average salinity difference is 0.33 (hyposaline, Sept. – Apr.) with strongest gradients observed during the winter storm season following enhanced freshwater discharge. Inverse salinity develops intermittently May – Aug. Subtidal heat flux is dominated by surface heating, whose daily average is always positive (heat input). The developed model does not quantify adequate heat export from the estuary, however, a sensitivity analysis indicates that diffusive flux may be a significant heat export component. Excess heat appears to be exported to the ocean, allowing ocean-estuary temperatures to remain similar. Characterizing estuarine dynamics like these enables us to predict how Morro Bay, and other similar estuarine systems, may respond to long and short-term environmental changes, and how these responses influence estuarine circulation and environmental health.