TY - JOUR
T1 - A modified METRIC model for high resolution partitioning and mapping of evapotranspiration over irrigated agricultural landscapes in Morocco
AU - Elfarkh, Jamal
AU - Hssaine, Bouchra Ait
AU - Er-Raki, Salah
AU - Ezzahar, Jamal
AU - McCabe, Matthew F.
AU - Chehbouni, Abdelghani
N1 - Publisher Copyright:
© 2025 The Authors
PY - 2025/6
Y1 - 2025/6
N2 - Partitioning of evapotranspiration (ET) into soil evaporative (E) and plant transpiration (T) components remains challenging in flux modeling that has particular relevance to crop water use management. Here, we develop an approach to modify the Mapping EvapoTranspiration at high Resolution and with Internalized Calibration model (METRIC) that allows improved partitioning to landscape-scale flux components. Referred to herein as METRIC-2S, the approach introduces a two-source scheme into the original one source model, using soil and vegetation temperatures to drive the partitioning process. These temperatures are used by METRIC to calculate two ET components, one for the soil and another for the vegetation, which are subsequently weighted by the fractional vegetation cover (fc) to compute E and T. Soil and vegetation temperatures are estimated using the hourglass method, which is driven by the surface temperature and fc. ET estimates from the original METRIC and revised METRIC-2S models are intercompared and validated against eddy covariance measurements over three agricultural sites, including an olive orchard, wheat field and a mixed wheat/olive plantation. Overall, METRIC-2S provides considerable improvements in accuracy relative to the original METRIC model over the three sites, with observed decreases in RMSE from 141 to 63 W/m2 at the olive site, 102 to 83 W/m2 over the wheat field and from 180 to 78 W/m2 at the mixed site. To evaluate the performance of the partitioning scheme, transpiration estimates are compared against available sap flow measurements over the olive orchard site for selected dates that coincide with a Landsat overpass, with an RMSE from this reduced sample of approximately 22.3 W/m2. While additional verification and assessment of component values are required, results suggest that the METRIC-2S approach represents a good trade-off between simplicity and improved accuracy.
AB - Partitioning of evapotranspiration (ET) into soil evaporative (E) and plant transpiration (T) components remains challenging in flux modeling that has particular relevance to crop water use management. Here, we develop an approach to modify the Mapping EvapoTranspiration at high Resolution and with Internalized Calibration model (METRIC) that allows improved partitioning to landscape-scale flux components. Referred to herein as METRIC-2S, the approach introduces a two-source scheme into the original one source model, using soil and vegetation temperatures to drive the partitioning process. These temperatures are used by METRIC to calculate two ET components, one for the soil and another for the vegetation, which are subsequently weighted by the fractional vegetation cover (fc) to compute E and T. Soil and vegetation temperatures are estimated using the hourglass method, which is driven by the surface temperature and fc. ET estimates from the original METRIC and revised METRIC-2S models are intercompared and validated against eddy covariance measurements over three agricultural sites, including an olive orchard, wheat field and a mixed wheat/olive plantation. Overall, METRIC-2S provides considerable improvements in accuracy relative to the original METRIC model over the three sites, with observed decreases in RMSE from 141 to 63 W/m2 at the olive site, 102 to 83 W/m2 over the wheat field and from 180 to 78 W/m2 at the mixed site. To evaluate the performance of the partitioning scheme, transpiration estimates are compared against available sap flow measurements over the olive orchard site for selected dates that coincide with a Landsat overpass, with an RMSE from this reduced sample of approximately 22.3 W/m2. While additional verification and assessment of component values are required, results suggest that the METRIC-2S approach represents a good trade-off between simplicity and improved accuracy.
UR - http://www.scopus.com/inward/record.url?scp=105004447740&partnerID=8YFLogxK
U2 - 10.1016/j.srs.2025.100233
DO - 10.1016/j.srs.2025.100233
M3 - Article
AN - SCOPUS:105004447740
SN - 2666-0172
VL - 11
JO - Science of Remote Sensing
JF - Science of Remote Sensing
M1 - 100233
ER -