Processes contributing to the evolution and destruction of stratification in the Liverpool Bay ROFI

• Published in: Ocean dynamics Vol. 61; no. 9; pp. 1403 - 1419
• Main Authors: Howlett, Eleanor R., Rippeth, Tom P., Howarth, John
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.09.2011; Springer Nature B.V
• Subjects: Atmospheric Sciences; Brackish; Buoyancy; Earth and Environmental Science; Earth Sciences; Evolutionary biology; Fluid- and Aerodynamics; Geophysics/Geodesy; Marine; Monitoring/Environmental Analysis; Oceanography; Potential energy; Stratification; Stratosphere; Topical Collection on the UK National Oceanography Centre’s Irish Sea Coastal Observatory; Liverpool Bay; ANE, British Isles, Liverpool Bay; Region of Freshwater Influence; Potential energy anomaly; Stratification; Strain-induced periodic stratification; Liverpool Bay
• ISSN: 1616-7341; 1616-7228
• DOI: 10.1007/s10236-011-0402-y

Liverpool Bay, a region of freshwater influence subject to semi-diurnal and enduring periods of stratification, is home to a long-term coastal observatory. The observatory provides a new array of data which include vertical profiles of velocity from an Acoustic Doppler Current Profiler and a high frequency radar system (which provides measurements of surface currents). Using this dataset in conjunction with an analytical potential energy model that uses advances in the formulation of a freshwater buoyancy term, the processes controlling stratification can be assessed. The results indicate that a depth-resolving freshwater buoyancy term should be used for the calculation stratification. Advection, in addition to depth-mean straining, is an important process affecting the stratification in Liverpool Bay. Specifically, when semi-diurnal stratification occurs, the two terms are in phase whilst when enduring stratification occurs, they are out of phase. The phase of the advective component, and thus its influence relative to depth-mean straining, was found to be a function of the vertical variation of the horizontal density gradient.