Signal Transmission from the Water Surface for Plastic Pollution Tracking

We use surface drifters to sample individual traces of floating macro plastic. These in-situ measurements provide input for the development of Lagrangian simulations to analyze both the dispersion patterns, and the physical transport processes of the plastic. An important component of drifters is the transmission of data directly from the water surface. This is challenging both due to the remoteness of the locations where the transmissions take place, and due to the dynamical movement of the water, which impedes signal transmission. For this reason, expensive satellite modems are often used, with careful design considerations that make the communication possible. The aims of our current research project are twofold: We want to test established and alternative terrestrial communication technologies at tens of kilometers from shore, and extend the knowledge about these data transmissions in challenging environments. This is done with a custom waterproof instrument that can be deployed and kept next to a research vessel. The instrument contains transition modems for satellite, cellular and LoRa communication. We present the construction of the instrument and results of a recent measurement campaign in the North Sea, off the Dutch coast.