Estimation of bell pepper evapotranspiration using two-source energy balance model based on high-resolution thermal and visible imagery from unmanned aerial vehicles

Tunca E., Köksal E. S., Torres-Rua A., Kustas W. P., Hector Nieto H. N.

JOURNAL OF APPLIED REMOTE SENSING, vol.16, no.2, 2022 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 16 Issue: 2
  • Publication Date: 2022
  • Doi Number: 10.1117/1.jrs.16.022204
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Aquatic Science & Fisheries Abstracts (ASFA), CAB Abstracts, Communication Abstracts, Compendex, INSPEC, Civil Engineering Abstracts
  • Keywords: evapotranspiration, bell pepper, unmanned aerial vehicle, two-source energy balance, soil water balance, HEAT-FLUX, DRIP-IRRIGATION, WATER, SOIL, FIELD, TRANSPIRATION, TEMPERATURES, COMPONENTS, EFFICIENCY, SCALE
  • Ondokuz Mayıs University Affiliated: Yes


Crop evapotranspiration (ET) is a crucial component of energy and water budgets. The accurate determination of ET is vital for agricultural water management. Several satellite-based ET models have been developed to map ET at the field to regional scales. The spatial resolution of the satellite observations, particularly thermal-infrared imagery, is insufficient to estimate ET for small (<1 ha) agricultural fields. With unmanned aerial vehicle (UAV) technology advancement, high spatial and temporal images can be acquired with UAVs to monitor ET for small fields or even at a canopy scale. The aim of this study was the evaluation of the two-source energy balance (TSEB) model to estimate daily and seasonal crop (bell pepper) ET (ETTSEB) using high-resolution visible and thermal UAV imagery. Also, the impact of using different pixel resolutions (40, 50, 60, and 70 cm) with TSEB is compared with ET values derived using a soil water budget approach (ETSWD) with a profile soil water content. The results of this study showed that there is a high correlation between ETTSEB and ETSWD values (R-2 = 0.73 for daily, R-2 = 0.98 for seasonal). The root mean square error values for daily and seasonal ETTSEB are 0.62 mm day(-1) and 11.46 mm season(-1), respectively. The sensitivity of TSEB output to the spatial resolution indicated that different pixel resolutions do not significantly impact ET estimates. We suggest that the TSEB model has a real potential for agricultural water management applications for small agricultural fields using high-resolution UAV multispectral and thermal images. (c) 2022 Society of Photo-Optical Instrumentation Engineers (SPIE)