Algea Bloom Monitoring Based on ML
Harmful algal blooms (HABs) harm marine life
and human health. Finding and tracking these events with
satellite data is cost-effective and scalable. This study focuses
on detecting Alexandrium, a harmful algae species, using data
from a small experimental region along the western coast
of Italy. All data were provided by Riccardo Bentivogli, a
PhD student at the University of Bologna, and the study was
conducted in collaboration with him. It looks at two ways to
use Convolutional Neural Networks (CNNs) for this task. The
first uses a simple CNN to find features in the data for early
analysis of cell concentration in regions. The second creates
a basic CNN classifier to train and test the data. Before the
training, we focused on atmospheric correction and turning
images into arrays. The results show that CNNs work well to
find patterns in satellite data but have issues like unbalanced
data and unclear features.
Atmospheric correction is an important step in satellite
image processing. It removes the effects of gases, aerosols,
and water vapor in the atmosphere from the captured data.
When sunlight interacts with the Earth’s surface, the satellite
sensor records both the light reflected from the surface and
the light scattered or absorbed by the atmosphere. Atmospheric correction ensures the signal represents the surface
accurately.
Satellite sensors typically provide two types of data:
• L1 Data: Measures Top-of-Atmosphere (TOA) radiance
[10], including contributions from the Earth’s surface
and atmospheric effects. This data is not corrected for
atmospheric influences.
• L2 Data: Represents Bottom-of-Atmosphere (BOA) reflectance, where atmospheric effects have been removed, offering accurate surface reflectance.
Sentinel-2 data was used for this research, which can
provide L2 products corrected for atmospheric effects using
built-in algorithms.