UC San Diego

Infragravity (IG) waves (periods ~ 25 s to 250 s) are known to dominate wave energy inside many shallow, bar built estuaries. However, beyond their importance for sediment buildup at the sill, little is known about the impact of IG waves on these shallow estuaries. I use observations from a focused deployment in Los Peñasquitos Lagoon in Southern California during a period of large wave forcing to understand the impacts of IG waves, with a particular focus on the turbulence generated through bottom friction. I also reflect on increasing pressure for scientists to work closely with lagoon managers in the development of their questions and conduct a study of academic culture to understand how similar changes are affecting coastal physical oceanographers. In Chapter 2, I describe the field deployment in detail and use initial observations to link IG waves to sediment transport and oscillations of salinity and temperature in the estuary. In Chapter 3, I develop new methods for despiking Accoustic Doppler Velocimeter (ADV) data and calculating turbulent dissipation from velocity measurements in the presence of IG waves. In particular I develop a new inertial subrange fitting method to improve turbulent dissipation measurement accuracy in any measurement conditions. In Chapter 4, I use those dissipation measurements to develop a new method for predicting turbulent dissipation in the wave boundary layer. I verify this method with a numerical model and observations, and use it to show that IG waves significantly increase turbulence in the estuary during neap tides and at the beginning of flood tide. In Chapter 5, I conduct 15 interviews of coastal physical oceanography professors in the United States. Using these interviews, I show that a disconnect between a relatively slowly changing academic culture and relatively swiftly changing external pressures have led to increased stress and a general over commitment of time for especially new professors in the field.