Antheia: Multi-decadal monitoring of open water cover on northern peatlands

Antheia will use Earth observation data to quantify changing surface water pools on northern peatlands. Peatlands represent one of the world’s most carbon-dense ecosystem types, and pools are hotspots for peatland-atmosphere carbon gas fluxes, biogeochemical processing, and aquatic biodiversity. Worryingly, evidence is growing that peatland pools across a range of northern biomes are beginning to change, in some cases rapidly, in response to climate change, with important potential consequences for peatland ecosystem functions and services. Pools are hotspots for methane emissions, and increasing pool area leads to increased emissions. In high latitudes, thaw pools are expanding across some permafrost peatlands. At the same time, longer, warmer growing seasons are causing these and other peatland pools at lower latitudes to be overgrown by semi-aquatic plants, causing some pools to shrink rapidly. Further still, shifting snowmelt regimes are affecting seasonal meltwater pools and reducing local water availability during growing seasons.  However, the evidence for these changes in pools is typically based on studies of individual sites, and there is currently no global system capable of monitoring peatland surface water cover at large scales. As such, it is unclear how widespread these changes in peatland pools are, how quickly they are proceeding, or whether pool area is growing or shrinking on a net basis in different climatic zones. Named after the ancient Greek deity of swamps and wetlands, Antheia will be the first system capable of providing such monitoring, using three decades of satellite radar data to look down upon the wet places of the world and assess their changing condition. 
Antheia will combine, refine and validate preliminary methods that we have developed and trialled, using satellite radar data to detect open water surfaces on peatlands, including beneath tree canopies. We will compare predictions from the new system to in situ monitoring of peatland pools, and to very-high-resolution satellite data that are available for recent years. We will then apply the system to current and historical satellite radar data from the northern hemisphere to estimate changes in the size of permanent peatland pools, and changes in the timing and extent of seasonal pools, such as those that develop after spring snowmelt. Finally, the project will deliver a free, public, online data portal that will allow users to query, visualise and download the latest estimates of peatland surface water cover from locations of their choice, based on automated processing of near-real-time satellite data. 

Impact

Antheia is unprecedented in terms of its scale and ambition for peatland monitoring, incorporating the entire northern peatland domain, and spanning more than three decades. The global nature of the project means that it will provide important benefits for NGOs and policy makers involved in peatland conservation and restoration, both in the UK and internationally, and to scientists involved in large-scale Earth surface modelling, and the study of catchment biogeochemistry and aquatic ecology. Antheia will deliver the first estimates of long-term changes in surface water cover across northern peatlands. This information will be of direct use in assessing the impacts of climate change upon these ecosystems, and directing conversation efforts such as hydrological management to those locations most in need of it. Targeted expert-user workshops throughout the project will leverage additional impact amongst scientific and stakeholder communities.