There are around 304 million lakes globally. These provide essential resources for human survival and are an important component of global biogeochemical cycles. Lakes are also fragile systems that are sensitive to multiple pressures including nutrient enrichment, climate change and hydrological modification, making them important ‘sentinels’ of environmental perturbation. However, traditional monitoring has only produced data from a tiny fraction of the global population of lakes and disentangling the causes of change requires consistently-produced data from a large number of lakes, along with measurements of possible causes of change. Satellite observations (remote sensing) and the establishment of a global lake observatory would produce a step-change in our ability to detect and attribute the causes of changes in lakes world-wide. This is now possible for three reasons: (1) the improved wavebands, spatial resolution and frequency of data collection from satellite sensors is now sufficient to monitor inland waters; (2) formulae to correct for atmospheric properties and to convert the detected reflected light to useful lake properties have been developed; and (3) computing power has increased to the point that allows near real time and archived information from satellites to be processed.
GloboLakes will analyse 20 years of data from more than 1000 large lakes across the globe to determine ‘what controls the differential sensitivity of lakes to environmental perturbation’. This is an ambitious project that is only possible by bringing together a consortium of scientists with complementary skills. These include expertise in remote sensing of freshwaters and processing large volumes of satellite images, collation and analysis of large-scale environmental data, environmental statistics and the assessment of data uncertainty, freshwater ecology and mechanisms of environmental change and the ability to produce lake models to forecast future lake conditions.
The project will focus on the retrieval of surface water temperature as this has a fundamental effect on lake ecology, the concentration of coloured dissolved organic matter and suspended solids that derive largely from the catchment, the abundance of phytoplankton measured as the concentration of the pigment, chlorophyll a, and the abundance of cyanobacteria (blue-green algae) that can potentially be toxic. Knowledge of the conditions of lakes and their sensitivity to change is also extremely valuable for the management of lakes and reservoirs and GloboLakes will provide information and products specifically for environmental managers. A satellite due to be launched during the course of the project, called Sentinel 2, will provide even greater spatial resolution allowing data to be collected and exploited from even smaller lakes. This will be investigated by GloboLakes and incorporated into the framework of a global lake observatory.