Emma Rutherford, Mechanical Engineering ’23

Sea to Space: NASA Satellite Images of Stellwagen Bank National Marine Sanctuary

What data do we get from a satellite?

The main input of a satellite ocean color radiometer is light (radiance). After correction for atmospheric interference, the variable we are left with is spectral remote sensing reflectance [Rrs(λ)]. The different cell sizes and shapes, inner structure, and composition of pigments of phytoplankton species create unique light absorption and backscattering properties which influence the shape of the Rrs spectra. This allows satellites to distinguish between different species of phytoplankton in the ocean.

Diagram of how satellite imaging works.

How many phytoplankton?

There are multiple size classes of phytoplankton. We will focus on the following two:

  • Microplankton (20-200 µm)
  • Nanoplankton (2-20 µm)


These microscopic organisms are so abundant that at the human scale we can’t tell they are there. Yet, at the planetary scale, these blooms are the signs of life we can capture with a satellite.