Title: | Evaluation of potential evapotranspiration based on CMADS reanalysis dataset over China |
Authors: | Tian, Y., K. Zhang, Y.-P. Xu, X. Gao and J. Wang |
Year: | 2018 |
Journal: | Water |
Volume (Issue): | 10(9) |
Pages: | |
Article ID: | 1126 |
DOI: | 10.3390/w10091126 |
URL (non-DOI journals): | |
Model: | none |
Broad Application Category: | data or component development |
Primary Application Category: | evapotranspiration assessment |
Secondary Application Category: | none |
Watershed Description: | Entire country of China. |
Calibration Summary: | |
Validation Summary: | |
General Comments: | |
Abstract: | Potential evapotranspiration (PET) is used in many hydrological models to estimate actual
evapotranspiration. The calculation of PET by the Food and Agriculture Organization of the United
Nations (FAO) Penman–Monteith method requires data for several meteorological variables that
are often unavailable in remote areas. The China Meteorological Assimilation Driving Datasets
for the SWAT model (CMADS) reanalysis datasets provide an alternative to the use of observed
data. This study evaluates the use of CMADS reanalysis datasets in estimating PET across China
by the Penman–Monteith equation. PET estimates from CMADS data (PET_cma) during the period
2008–2016 were compared with those from observed data (PET_obs) from 836 weather stations in
China. Results show that despite PET_cma overestimating average annual PET and average seasonal
in some areas (in comparison to PET_obs), PET_cma well matches PET_obs overall. Overestimation of
average annual PET occurs mainly for western inland China. There are more meteorological stations
in southeastern China for which PET_cma is a large overestimate, with percentage bias ranging from
15% to 25% for spring but a larger overestimate in the south and underestimate in the north for the
winter. Wind speed and solar radiation are the climate variables that contribute most to the error
in PET_cma. Wind speed causes PET to be underestimated with percentage bias in the range -15%
to -5% for central and western China whereas solar radiation causes PET to be overestimated with
percentage bias in the range 15% to 30%. The underestimation of PET due to wind speed is offset by
the overestimation due to solar radiation, resulting in a lower overestimation overall. |
Language: | English |
Keywords: | potential evapotranspiration; Penman-Monteith; CMADS; China |