The use
of multispectral geostationary
satellites to study aquatic ecosystems improves the temporal frequency
of observations and mitigates cloud obstruction, but no operational
capability presently exists for the coastal and inland waters of the
United States. The Advanced Baseline Imager (ABI) on the current
iteration of the Geostationary Operational Environmental Satellites,
termed the
R
Series (GOES-R), however, provides
sub-hourly imagery and the opportunity to overcome this deficit and to
leverage a large repository of existing GOES-R aquatic observations.
The fulfillment of this opportunity is assessed herein using a
spectrally simplified, two-channel aquatic algorithm consistent with
ABI wave bands to estimate the diffuse attenuation coefficient for
photosynthetically available radiation,
K
d
(
P
A
R
)
. First, an in
situ ABI dataset was synthesized using a globally
representative dataset of above- and in-water radiometric data
products. Values of
K
d
(
P
A
R
)
were estimated by fitting the ratio
of the shortest and longest visible wave bands from the in situ ABI dataset to coincident, in situ
K
d
(
P
A
R
)
data products. The algorithm was
evaluated based on an iterative cross-validation analysis in which 80%
of the dataset was randomly partitioned for fitting and the remaining
20% was used for validation. The iteration producing the median
coefficient of determination (
R
2
) value (0.88) resulted in a root mean
square difference of
0.319
m
−
1
, or 8.5% of the range in the
validation dataset. Second, coincident mid-day images of central and
southern California from ABI and from the Moderate Resolution Imaging
Spectroradiometer (MODIS) were compared using Google Earth Engine
(GEE). GEE default ABI reflectance values were adjusted based on a
near infrared signal. Matchups between the ABI and MODIS imagery
indicated similar spatial variability (
R
2
=
0.60
) between ABI adjusted blue-to-red
reflectance ratio values and MODIS default diffuse attenuation
coefficient for spectral downward irradiance at 490 nm,
K
d
(
490
)
, values. This work demonstrates that
if an operational capability to provide ABI aquatic data products was
realized, the spectral configuration of ABI would potentially support
a sub-hourly, visible aquatic data product that is applicable to
water-mass tracing and physical oceanography research.