Peatlands are important carbon sinks however many peatlands have been degraded. This lowers the water level releasing greenhouse gases into the atmosphere. Synthetic aperture radar (SAR) satellite data can be used to monitor the water level in peatlands and therefore identifies areas that are in need of restoration. Using quad-pol L-band data from ALOS-2 shows potential to identify negative change in the water level. Observing eigenvalues and eigenvectors of the change matrix of a bog in Scotland identifies a lower water table (drier peatland) that corresponds with less surface scattering. In addition, observing the coherence regions of different points around peatlands shows variations in the scattering. Improvements to these results would be made by obtaining acquisitions on dates which had a higher water table.

Directly remote sensing plastic pollution within the open ocean has proven to be challenging. Therefore, other methods of detecting marine plastics through a proxy should be explored. Radar satellites are sensitive to surface roughness and can therefore detect dampening of wind-driven capillary waves on the sea surface. Plastics within the ocean have been found to be colonized by microbes, which can produce surfactants, substances which can dampen the short capillary waves on the ocean. This research investigates whether a ground radar instrument is capable of detecting plastisphere-based surfactant dampening within a semi-natural environment setting. We find that we can observe reduced backscatter from dampening effects that are occurring within our experiment setting. We also find that the backscattering from experiments involving plastisphere-based surfactants are significantly different from control experiments where microbial production is stopped.

The remote sensing of marine plastics is a relatively new field and research into radars capabilities for monitoring / detection is mostly limited. Here, we utilize the use of a C- and X-band ground radar to understand the capabilities for monitoring marine plastic pollution. Results show that backscattering differences can be found between reference acquisitions of clean water and test water filled with plastics, in both C- and X-band frequencies. With X-band detecting significant differences in backscattering in 48/68 test cases, and C-band detecting differences in 20/67 test cases.

With remote sensing increasingly used to support peatland management, this study evaluates the potential of quad-polarimetric L-band SAR for water table depth (WTD) monitoring. We produced Random Forest models predicting WTD, and temporal WTD variation, across multiple locations and dates at a Scottish raised bog, based on observables derived from quad-pol L-band SAR data. Like other studies, our models showed limited ability (R2= 0.05) to predict WTD across multiple locations. However, significant validated performance (R2= 0.66) was found when predicting temporal WTD variation, exceeding the performance found by comparable studies using C-band SAR. Therefore, further work using quad-pol L-band SAR is recommended, particularly to understand and correct for the effects of non-WTD characteristics on SAR signal which limit model performance spatially.

Plastics in the riverine environment are of major concern due to their potential pathways into the wildlife and more generally the ocean. Dams are capable of trapping marine plastics within the riverine environment. This entrapment changes the surface roughness of the area with the marine debris. Radar satellites are sensitive to surface roughness and can therefore detect these changes. This research investigates areas in Serbia and Boznia & Herzegovina using ESA Sentinel-1 polarimetric SAR data. This study shows the feasibility of detecting large accumulations of plastic near dams, with detectors capable of achieving 75-85% positive detection ratings with a 0.1% false alarm rate. Additionally, we find the use of single VV polarization is inadequate for this task and PolSAR data are needed.

Plastics within the ocean have been found to be colonised by microorganisms that, as a by-product of their metabolism, produce surfactants. Short capillary waves on the sea surface can get dampened due to the increased surface elasticity of these surfactants. Radar satellites are sensitive to surface roughness and can therefore detect the dampening of these waves. This research investigates areas inside the Atlantic, Pacific and Indian Ocean gyres using ESA Sentinel-1 and DLR TerraSAR-X data. We found out that we can observe several surfactant instances in the gyres and these are not correlated to medium or high level of chlorophyll. We can exclude that they have origin in biogenic slicks. Among other possible unknown origins, we hypothesise that these surfactants are produced from plastic concentrations within the ocean.

This study is the first application of harmonic analysis to remotely sensed chlorophyll-a concentration in lakes. Freshwater phytoplankton phenology can track the development of algal blooms in lakes. The dynamics of algal blooms in Lake Balaton is analyzed over 9 years by harmonic analysis of MERIS-derived chlorophyll-a estimates. An analysis of the significance of the individual harmonic terms at each significant frequency provides the amplitudes and phases. Four lake basins are analyzed and phenological indicators are presented. The basins show distinct algal bloom phenologies.