Forecasting harmful algal blooms over the coastal water, Charlotte
County, Florida
Abstract
Harmful algal blooms (HAB; Karenia brevis) occurrences have been
reported from the coastal waters of Charlotte County in southwest
Florida. We developed multivariate regression models that relate
reported (January 2010 to October 2017) bloom occurrences to
observations extracted from archival remote sensing data (Moderate
Resolution Imaging Spectroradiometer [MODIS]) to accomplish the
following: (1) identify factors controlling HAB propagation, (2) predict
algal bloom distribution (same day, and 1, 2, and 3 days in advance),
and (3) develop fully automated system for data distribution via a
web-based GIS platform. These tasks were accomplished through three main
steps: (1) automatic downloading and processing of daily MODIS products
using SeaDAS software to extract relevant remote sensing variables
(euphotic depth, wind direction, ocean chlorophyll three-band algorithm
for MODIS [Chlorophyll a OC3M], wind speed, chlorophyll a
Generalized Inherent Optical Property [GIOP], Fluorescence Line
Height [Flh], diffused attenuation coefficient for downwelling
irradiance at 490 nanometer [Kd_490], chlorophyll a Garver-Siegel-
Maritorena [GSM], Turbidity index, Particulate backscattering
coefficient at 547 nm [bbp_547_giop] and sea surface temperature
[SST]), (2) development and calibration of multivariate regression
models using relevant remote sensing and static variable (distance from
river mouth, bathymetry) inputs for same day mapping and forecasting of
HAB occurrences, and (3) automated posting of model outputs on a
web-based GIS (http://mgs.geology.wmich.edu/bloom/). Findings include:
(1) the variables most indicative of the timing of bloom propagation are
bathymetry, euphotic depth, wind direction, sea surface temperature
[SST], chlorophyll a [OC3M] and distance from the river mouth,
and (2) the model predictions were successful at 90% for same day
mapping and 65%, 72% and 71% for the one, two and three days in
advance predictions, respectively.