Accession Number:

ADA523159

Title:

Upwelling Dynamics off Monterey Bay: Heat Flux and Temperature Variability, and their Sensitivities

Descriptive Note:

Bachelor's thesis

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING

Personal Author(s):

Report Date:

2010-05-01

Pagination or Media Count:

70.0

Abstract:

Understanding the complex dynamics of coastal upwelling is essential for coastal ocean dynamics, phytoplankton blooms, and pollution transport. Atmospheric-driven coastal upwelling often occurs when strong alongshore winds and the Coriolis force combine to displace warmer surface waters offshore, leading to upward motions of deeper cooler, nutrient-dense waters to replace these surface waters. Using the models of the MIT Multidisciplinary Simulation, Estimation, and Assimilation System MSEAS group, we conduct a large set of simulation sensitivity studies to determine which variables are dominant controls for upwelling events in the Monterey Bay region. Our motivations include determining the dominant atmospheric fluxes and the causes of high-frequency fluctuations found in ocean thermal balances. We focus on the first upwelling event from August 1- 5, 2006 in Monterey Bay that occurred during the Monterey Bay 06 MB06 at-sea experiment for which MSEAS data-assimilative baseline simulations already existed. Using the thermal energy temperature, salinity and momentum velocity conservation equations, full ocean fields in the region as well as both control volume flux balances and local differential term-by-term balances for the upwelling event events were computed. The studies of ocean fields concentrate on specific depths surface-0m, thermocline-30m and undercurrent-150m. Effects of differing atmospheric forcing contributions wind stress, surface heatingcooling, and evaporation-precipitation on these full fields and on the volume and term-by-term balances are analyzed. Tidal effects are quantified utilizing pairs of simulations in which tides are either included or not. Effects of data assimilation are also examined. We find that the wind stress forcing is the most important dynamical parameter in explaining the extent and shape of the upwelling event.

Subject Categories:

  • Physical and Dynamic Oceanography
  • Fluid Mechanics
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE