Description of surface transport in the region of the Belizean Barrier Reef based on observations and alternative high-resolution models
2016-09,
Lindo-Atichati, David,
Curcic, Milan,
Paris, Claire B.,
Buston, Peter M.
The gains from implementing high-resolution versus less costly low-resolution models to
describe coastal circulation are not always clear, often lacking statistical evaluation. Here
we construct a hierarchy of ocean-atmosphere models operating at multiple scales within
a 1×1° domain of the Belizean Barrier Reef (BBR). The various components of the
atmosphere-ocean models are evaluated with in situ observations of surface drifters, wind
and sea surface temperature. First, we compare the dispersion and velocity of 55 surface
drifters released in the field in summer 2013 to the dispersion and velocity of simulated
drifters under alternative model configurations. Increasing the resolution of the ocean
model (from 1/12° to 1/100°, from 1 day to 1 h) and atmosphere model forcing (from
1/2° to 1/100°, from 6 h to 1 h), and incorporating tidal forcing incrementally reduces
discrepancy between simulated and observed velocities and dispersion. Next, in trying to
understand why the high-resolution models improve prediction, we find that resolving
both the diurnal sea-breeze and semi-diurnal tides is key to improving the Lagrangian
statistics and transport predictions along the BBR. Notably, the model with the highest
ocean-atmosphere resolution and with tidal forcing generates a higher number of looping
trajectories and sub-mesoscale coherent structures that are otherwise unresolved. Finally,
simulations conducted with this model from June to August of 2013 show an
intensification of the velocity fields throughout the summer and reveal a mesoscale
anticyclonic circulation around Glovers Reef, and sub-mesoscale cyclonic eddies formed
in the vicinity of Columbus Island. This study provides a general framework to assess the
best surface transport prediction from alternative ocean-atmosphere models using metrics
derived from high frequency drifters’ data and meteorological stations.