Evaluation of soil moisture in CMIP6 multi-model simulations over
conterminous China
Abstract
The Sixth Phase of the Coupled Model Intercomparison Project (CMIP6)
provides the long-term soil moisture (SM) products and this study
conducts a comprehensive assessment of SM products of multiple CMIP6
model simulations over conterminous China. Both near-surface (0-10 cm)
SM simulations from 40 models and root-zone (0-100 cm) SM from 25 models
are compared with a set of station measurements in the growing season
(April to September) for 1992-2013 in term of magnitude, spatial and
temporal variability, and the long-term trend and interannual
variability of near-surface SM for 1961-2014 are further evaluated with
an offline land surface modeling dataset. Simulations from most models
broadly capture the spatial characteristics of observation and the
multi-model mean (MME) well reproduces seasonal variations over majority
regions regardless of large-spread across models. Models from the same
institution likely manifest similar performances and the land surface
scheme plays a dominant role in the SM reproduction. The majority of
models well simulate the overall drying trend in China as a whole and
the signs of SM trend are highly consistent across models, but the areas
with significant wetting/drying trends vary with models. The spatial
patterns of SM interannual variability are model-dependent in term of
spatial patterns. MME is overall superior to the simulations of
individual model and may have potential applications in the future
research. The heterogeneity SM performances across models reveal the
complexity in modeling land surface variables, suggesting the need for
improving representations of land surface processes in the coupled
models.