Estimation of Evapotranspiration Using SEBAL Algorithm and Landsat-8 Data—A Case Study: Tatra Mountains Region

Abstract

ET (Evapotranspiration) is one of the climate elements, which plays an important role in water balance, and effects on the ecosystem of any region. Therefore, many mathematical equations and algorithms have been found and designed to calculate and estimate values of evapotranspiration. Calculation methods are either based on data from meteorological stations or using other sources of data where the area is lacking from meteorological stations. Remote sensing data are one of the important sources and techniques to estimate many climate elements including evapotranspiration. The selected study area is located in Tatra Mountains on the borders between Poland and Slovakia. Tatra Mountains are the most valuable areas in Poland and Slovakia. The main objective of current study is to estimate the spatial variation of ET using SEBAL algorithm and Landsat-8 imagery. The analysis is carried out using Landsat-8 (OLI/TIRS) data, ASTER GDEM and reference weather parameters. Sixteen ERDAS models are prepared to calculate the various parameters related to solar radiation. The models are prepared to calculate the values of surface radiance surface reflectance, surface albedo, NDVI, LAI, surface emissivity, surface temperature, net radiation, soil heat flux, sensible heat flux, latent heat flux, which are consequently used to calculate the hourly and daily evapotranspiration in study area. Results of pixel wise calculations show the values of surface temperature which are varied from 6.

Estimation of mass and energy balance of glaciers using a distributed energy balance model over the Chandra river basin (Western Himalaya)

“…SWI is the direct and diffuse solar radiation flux that reaches the earth's surface. In this study, the clear sky conditions as an assumption were taken into account for the SWI estimation (Beg, Al‐Sulttani, Ochtyra, Jarocińska, & Marcinkowska, 2016), calculated using Equation : where G SC is the solar constant (1367 W m −2 ); cos θ is the cosine of the solar incidence angle; d r is the inverse squared relative earth–sun distance (Equation ); and τ SW is the atmospheric transmissivity (Equation ).…”

“…SWI is the direct and diffuse solar radiation flux that reaches the earth's surface. In this study, the clear sky conditions as an assumption were taken into account for the SWI estimation (Beg, Al-Sulttani, Ochtyra, Jaroci nska, & Marcinkowska, 2016), calculated using Equation ( 12):…”

Retrieval of Land Surface Temperature from Landsat-8 Thermal Infrared Sensor Data

“…Sharma et al (2015) [25] developed relationships between biophysical parameters and land surface temperature (LST) in Kolkata city and nearby surrounding areas. Beg et al (2016) [26] have calculated surface radiance, surface reflectance, surface albedo, NDVI, LAI, surface emissivity, and surface temperature. The selected study area was located in the Tatra Mountains on the borders between Poland and Slovakia.…”