  The prevailing approaches for ET retrievals are either limited in
spatiotemporal coverage or largely influenced by choice of input data or
simplified model physics, or a combination thereof. Here, using an independent
mass conservation approach, we develop water balance-based ET datasets (ET-WB)
for the global land and the selected 168 major river basins. We generate 4669
probabilistic unique combinations of the ET-WB leveraging multi-source datasets
(23 precipitation, 29 runoff, and 7 storage change datasets) from satellite
products, in-situ measurements, reanalysis, and hydrological simulations. We
compare our results with the four auxiliary global ET datasets and previous
regional studies, followed by a rigorous discussion of the uncertainties, their
possible sources, and potential ways to constrain them. The seasonal cycle of
global ET-WB possesses a unimodal distribution with the highest (median value:
65.61 mm/month) and lowest (median value: 36.11 mm/month) values in July and
January, respectively, with the spread range of roughly +/-10 mm/month from
different subsets of the ensemble. Auxiliary ET products illustrate similar
intra-annual characteristics with some over/under-estimation, which are
completely within the range of the ET-WB ensemble. We found a gradual increase
in global ET-WB from 2003 to 2010 and a subsequent decrease during 2010-2015,
followed by a sharper reduction in the remaining years primarily attributed to
the varying precipitation. Multiple statistical metrics show reasonably good
accuracy of monthly ET-WB (e.g., a relative bias of +/-20%) in most river
basins, which ameliorates at annual scales. The long-term mean annual ET-WB
varies within 500-600 mm/yr and is consistent with the for auxiliary ET
products (543-569 mm/yr). Observed trend estimates, though regionally
divergent, are evidence of the increasing ET in a warming climate.
