Abstract
Water scarcity is one of the most important problems of agroecosystems in Mediterranean and semiarid areas, especially for species such as vineyards that largely depend on irrigation. Actual evapotranspiration (ET) is a variable that represents water consumption of a crop, integrating climate and biophysical variables. Actual evapotranspiration models based on remote sensing data from visible bands of Sentinel-2, including Penman-Monteith–Stewart (RS-PMS) and Penman-Monteith–Leuning (RS-PML), were evaluated at different temporal scales in a Cabernet Sauvignon vineyard (Vitis vinifera L.) located in central Chile, and their performance compared with independent ET measurements from an eddy covariance system (EC) and outputs from models based on thermal infrared data from Landsat 7 and Landsat 8, such as Mapping EvapoTranspiration with high Resolution and Internalized Calibration (METRIC) and Priestley–Taylor Two-Source Model (TSEB-PT). The RS-PMS model showed the best goodness of fit for all temporal scales evaluated, especially at instantaneous and daily ET, with root mean squared error (RMSE) of 28.9 Wm−2 and 0.52 mm day−1, respectively, and Willmott agreement index (d1) values of 0.77 at instantaneous scale and 0.7 at daily scale. Additionally, both approaches of RS-PM model were evaluated incorporating a soil evaporation estimation method, one considering the soil water content (fSWC) and the other hand, using the ratio of accumulated precipitation and equivalent evaporation (fZhang), achieving the best fit at instantaneous scale for RS-PMS fSWC method with relative root mean squared error (%RMSE) of 15.2% in comparison to 58.8% of fZhang. Finally, the relevance of the RS-PMS model was highlighted in the assessment and monitoring of vineyard drip irrigation in terms of crop coefficient (Kc) estimation, which is one of the methods commonly used in irrigation planning, yielding a comparable Kc to the one obtained by the EC tower with a bias around 9%.
Highlights
Water is becoming increasingly scarce, especially for agricultural activities, and its demand for agricultural purposes is projected to increase 60% by 2050 [1], especially in irrigated crops [1,2,3,4,5]
Remote sensing-based ET models are classified in two different groups depending on the type of information used: (a) models based on thermal infrared bands (TIR-ET), and (b) models based on visible and near-infrared bands (VIS-ET) [17]
The Penman-Monteith model was evaluated for the estimation of actual evapotranspiration (ET) with remote sensing data (RS-PM) at multiple temporal scales, on a vineyard located in central Chile and under drip irrigation
Summary
Water is becoming increasingly scarce, especially for agricultural activities, and its demand for agricultural purposes is projected to increase 60% by 2050 [1], especially in irrigated crops [1,2,3,4,5]. A key element for water management in vineyards is the accurate measurement of water use via evapotranspiration (ET) both in time and Remote Sens. Obtaining this type of information is possible through remote sensing-based data [11,12,13,14,15,16] and models that use retrieved information to assess evapotranspiration. Remote sensing-based ET models are classified in two different groups depending on the type of information used: (a) models based on thermal infrared bands (TIR-ET), and (b) models based on visible and near-infrared bands (VIS-ET) [17]. TIR-ET models are capable of estimating land surface temperature (LST) from thermal infrared remote sensing data, allowing the determination of plant water status [11]
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