Ensemble Satellite Land Products Deepen the Interpretation of Drought Impacts on Terrestrial Carbon Cycle in Europe Over 2001–2015

Abstract

Recently, drought is recognized as a crucial factor on controlling inter-annual variations of the terrestrial carbon cycle. Remote sensing of hydrological and ecological land surface variables offers a very important aid for identifying the impact of droughts on terrestrial ecosystems. GLEAM soil moisture (SM), reconstructed GRACE terrestrial total terrestrial water storage change (TWS), GIMMS normalized difference vegetation index (NDVI), reconstructed continuous solar-induced fluorescence (SIF) data from OCO-2, and SIF data from SCIACHAMY and GOME-2, in conjunction with multiple carbon flux data and CRUNCEP meteorological data, were employed to study the drought impacts on the terrestrial ecosystems in Europe during 2001–2015. We found GLEAM SM and GRACE TWS can effectively detect hydrological anomalies for four reported strongest drought years on the continental scale, in line with evident reductions of terrestrial carbon uptake indicated by models. Most vegetation products agree well on indicating drought impacts, but with some unexpected inconsistencies. Also, these land products are able to reasonably indicate the spatial patterns of drought impacts on ecosystems. We highlight the importance of ensemble satellite land products in deepening the interpretation of drought impacts on terrestrial ecosystems, and also on examining carbon cycle models and identifying potential gaps in satellite data products within the context of drought-carbon cycle studies.