El Niño–La Niña cycle and recent trends in continental evaporation

Abstract

The hydrological cycle is expected to intensify in response to global warming. Yet, little unequivocal evidence of such an acceleration has been found on a global scale. This holds in particular for terrestrial evaporation, the crucial return flow of water from land to atmosphere. Here we use satellite observations to reveal that continental evaporation has increased in northern latitudes, at rates consistent with expectations derived from temperature trends. However, at the global scale, the dynamics of the El Niño/Southern Oscillation (ENSO) have dominated the multi-decadal variability. During El Niño, limitations in terrestrial moisture supply result in vegetation water stress and reduced evaporation in eastern and central Australia, southern Africa and eastern South America. The opposite situation occurs during La Niña. Our results suggest that recent multi-year declines in global average continental evaporation8,9 reflect transitions to El Niño conditions, and are not the consequence of a persistent reorganization of the terrestrial water cycle. Future changes in continental evaporation will be determined by the response of ENSO to changes in global radiative forcing, which still remains highly uncertain

Temperature and Snow-Mediated Moisture Controls of Summer Photosynthetic Activity in Northern Terrestrial Ecosystems between 1982 and 2011

“…This finding is consistent with the ongoing intensification of the hydrological cycle observed at high latitudes due to increases in both precipitation and evapotranspiration [63,64]. A similar impact of surface warming on drought severity since the 1980s has been documented on a global scale by recent studies based on the scPDSI using a Penman-Monteith formulation for potential evapotranspiration, but forced with different meteorological datasets [11,43,65,66].…”

Water, Energy, and Carbon with Artificial Neural Networks (WECANN): a statistically based estimate of global surface turbulent fluxes and gross primary productivity using solar-induced fluorescence

“…It also has the lowest RMSE based on our TC error estimates (Fig. S4-S6), despite its reported underestimated interannual variability due to the use of climatological values for several meteorological drivers (Miralles et al, 2014a. Such a tendency can also be summarized from the global difference maps, which show that FLUXNET-MTE has the best agreement with WECANN retrievals.…”

“…The data are provided at a 0.25 • × 0.25 • spatial resolution and daily temporal resolution and start in 1980. GLEAM data have been used for studying land-atmosphere interactions and the global water cycle (Guillod et al, 2014, Miralles et al, 2011a, 2014a. In this study, we use LE and H estimates from the latest version v3.0a (Martens et al, 2017).…”

The WACMOS-ET project – Part 2: Evaluation of global terrestrial evaporation data sets

“…For the fraction of open water at each pixel, the model assumes potential evaporation. GLEAM has recently been applied to look at trends in the water cycle (Miralles et al, 2014b) and land-atmospheric feedbacks (Guillod et al, 2015;Miralles et al, 2014a).…”