Progress in space-borne studies of permafrost for climate science: Towards a multi-ECV approach

Abstract

Remotely-sensed climate data records (CDRs) provide a basis for spatially distributed global climate model (GCM) inputs and validation methods. GCMs can take advantage of land surface models (LSMs), which aim to resolve surface energy, water and carbon budgets and hence these LSMs present important boundary conditions at the land-atmosphere interface. Pertinently, satellite data assimilation approaches are essential for improved land surface modelling for northern high latitudes ecosystems where permafrost degradation is reported to be ongoing. Permafrost, however, is an Essential Climate Variable (ECV) that cannot directly be monitored from space. Here, we advocate that CDRs, such as those compiled under the European Space Agency (ESA) Climate Change Initiative (CCI) programme, may be used in combination with permafrost models to improve our understanding of permafrost extent and degradation in a changing climate system. We describe the current types of remotely-sensed surface feature products that are widely used as indicators for permafrost related features. Furthermore, we highlight issues of using these site-specific permafrost proxies related to spatial scale, as well as the uncertainties in establishing present-day permafrost extent itself. Our assessment of the key ECVs that impact on permafrost, demonstrates how models that incorporate EO CDRs have the potential to boost our knowledge of permafrost conditions through better parametrisation of the thermal regime of permafrost soils.