Where next with Earth Observation of coastal water quality?

Earth observation (EO) data have a key, cost-effective, role to play in assisting coastal monitoring and management around the Australian continent, helping to overcome the paucity of bio-physical data across otherwise remote... [ view full abstract ]

Earth observation (EO) data have a key, cost-effective, role to play in assisting coastal monitoring and management around the Australian continent, helping to overcome the paucity of bio-physical data across otherwise remote and inaccessible areas. Physics-based water quality retrieval over the GBR World Heritage area using satellite remote sensing has allowed more frequent and accurate large-scale water quality estimates from space than was previously possible. Growing archives of EO data allow for the long-term observation of trends and changes in key biophysical parameters to inform on wider biodiversity and ecosystem processes.

Future extension of this work could include 1) extension to other regions of the Australian coastline and to inland waters, 2) algal bloom monitoring, 3) extension to new sensors, including higher spatial resolution observations closer to the coastline and 4) extension of methods to develop new products. These developments are not without their challenges as little is known of the general optical properties in many regions around the Australian coastline (knowledge required for improved algorithm performance) and where considerable differences in optical conditions exists between wet and dry seasons. For bloom monitoring, new hyper-spectral sensors and observations from geostationary orbiting sensors will be also need to be integrated. Higher resolution products nearer to the coast will need to cope with increased optical complexity where algal biomass is only a small fraction of the optical budget. Adapting the approach for recent and future new Earth observation sensor data should see new algorithms with improved uncertainty estimates, and products with greater accuracy and greater frequency, all to provide insight into regional limitations. Further integration of remotely sensed data into biogeochemical models will assist in providing powerful new forecasting tools. In all aspects, translation of the results to address management requirements in the marine environment will need to be paramount.

We will present a review on recent advances in water quality monitoring using EO data, and, to stimulate discussion, propose a range of options and challenges for extending such coverage to other regions and sensors including the definition of new applications and products.