Bulletin of the American Meteorological Society 99(8), S34
Abstract
Evaporation estimates are crucial to determine
water availability for human use, analyze ecosystem productivity and species richness, and monitor
agricultural needs for irrigation (Fisher et al. 2017).
Moreover, quantifying the return flow of water
from terrestrial surfaces to the atmosphere enables
the detection of land use and climate impacts on
the hydrological cycle (Dolman et al. 2014). Despite
being seldom measured in situ and not directly observed from space, a range of datasets exists today to
monitor evaporation at continental scales (McCabe
et al. 2016; Miralles et al. 2016; Yo. Zhang et al. 2019).
These datasets are hybrids between observations
and modeling and have been used to study trends
in hydrology and climate (Jung et al. 2010; Zhang et
al. 2016; Cheng et al. 2017); impacts of climate oscillations (Miralles et al. 2014b; Martens et al. 2018);
irrigation requirements (Anderson et al. 2015); and
hydrometeorological extremes (Miralles et al. 2014a;
Mu et al. 2013). Only a few of the existing datasets are
produced in near-real time and, typically, only for
specific continents (Ghilain et al. 2011; Anderson et
al. 2011). Data for this analysis were obtained from
the Global Land Evaporation Amsterdam Model
(GLEAM; Miralles et al. 2011) version v3.2a (Martens
et al. 2017), a simple land surface scheme run with
satellite data. While not deliberately designed with
an operational intent, GLEAM is updated with a few
months’ latency and has been widely validated in
multiple initiatives over the past few years (McCabe
et al. 2016; Miralles et al. 2016).