ENSO dominates multi-decadal dynamics in terrestrial evaporation

A recent study funded by the European Space Agency has just been published in Nature Climate Change (Miralles et al., 2013). The work uses satellite data of terrestrial evaporation (ET), together with independent observations of soil moisture and NDVI, to uncover a strong link between ET and the dynamics of the El Niño-La Niña cycle.

Miralles et al. (2013) suggest that previously reported declines in global average ET are not the consequence of a recent reorganization of the water cycle, but a product of internal climate variability. During El Niño, limitations in the supply of moisture in central Australia, southern Africa and eastern South America cause vegetation water-stress and constrain evaporation. These regional ET declines are so pronounced that govern the total volumes of water vapour from continental land surfaces into the atmosphere. On the other hand, in northern latitudes where the effects of ENSO are weaker, continental evaporation has raised since the '80s at rates that are consistent with expectations based on air temperature trends.

Reference:
Miralles, D.G., M.J. van den Berg, J.H. Gash, R.M. Parinussa, R.A.M. de Jeu, H.E. Beck, T.R.H. Holmes, C. Jiménez, N.E.C. Verhoest, W.A. Dorigo, A.J. Teuling and A.J. Dolman (2013), El Niño-La Niña cycle and recent trends in continental evaporation, Nature Clim. Change, doi: 10.1038/nclimate2068, 2013.