Quantification and Mapping of Satellite Driven Surface Energy Balance Fluxes in Semi-Arid to Arid Inter-Mountain Region

Remote Sensing

Vivek Sharma¹  Bibek Acharya¹  Fabian Nippgen²  Daniel Tekiela³  James Heitholt³ 

[1] Agricultural and Biological Engineering Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA;Department of Ecosystem Sciences and Management, College of Agriculture and Natural Resources, University of Wyoming, Laramie, WY 82071, USA;Department of Plant Sciences, College of Agriculture and Natural Resources, University of Wyoming, Laramie, WY 82071, USA;

关键词: crop evapotranspiration;    surface energy balance flux;    METRIC;    Landsat;    mountain region;   

DOI  :  10.3390/rs12244019

来源: DOAJ

【 摘 要 】

Crop evapotranspiration (ET_c) estimates, on a regional scale, hold enormous potential in managing surface and groundwater resources. This is particularly important for the headwater state of Wyoming, which provides water to found major river basins of the US. In this study, METRIC (Mapping evapotranspiration at high resolution with internalized calibration), a satellite-based image processing model, was used to map and quantify daily, monthly, and seasonal ET_c and other energy balance fluxes, i.e., net radiation (R_n), sensible heat (H), and soil heat flux (G) dynamics for different land-use classes. Monthly and seasonal ETc estimated were further used to approximate regional water consumption patterns for different land-use types for nine irrigation districts in semi-arid to arid intermountain region of Big Horn Basin (BHB), Wyoming. The validation of METRIC retrievals against Bowen ratio energy balance system (BREBS) fluxes measured over three vegetative surfaces, viz. sugar beet in 2017, dry bean in 2018, and barley in 2019, indicated high accuracy. The pooled correlation observed between estimated (pooled) and measured instantaneous fluxes had R² values of 0.91 (RMSE = 0.08 mm h⁻¹, NSE = 0.91), 0.81 (RMSE = 49.6 Wm⁻², NSE = 0.67), 0.53 (RMSE = 27.1 Wm⁻², NSE = 0.53), and 0.86 (RMSE = 59.2 Wm⁻², NSE = 0.84) for ET_c, R_n, G, and H, respectively. The biggest discrepancy between measured and estimated monthly ETc values was observed during times when BREBS flux tower footprint was devoid of any crops or the crops at footprint were not actively transpiring. Validation results improved when comparisons were made on monthly scales with METRIC underestimating growing season ET_c in the range between 3.2% to 6.0%. Seasonal ETc by land-use type showed significant variation over the study area where crop ETc was 52% higher than natural vegetation ETc. Furthermore, it was found that, in the arid to semi-arid intermountain region of Wyoming, the contribution of irrigation to total seasonal ETc varied in the range of 73–81% in nine irrigation districts that fall within the study area. The high relative contribution of irrigation highlights the importance of identifying and quantifying ETc for improved management in irrigation system design and water allocation.

【 授权许可】

Unknown