Affiliation(s)
1. Department of Geography, College of Education, University of Mustansiriyah, Baghdad, Iraq
2. Department of Regional Planning, College of Physical Planning, University of Kufa, Najaf, Iraq
3. Department of Geoinformatics, Cartography and Remote Sensing, Faculty of Geography and Regional Studies, University of Warsaw, Warsaw, Poland
4. College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Warsaw, Poland
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 6.2 oC
at mountain shadow areas to 34.6 oC at bare rocks and bare land
area, while the spatial variation of ET at different land covers shows the
hourly ET ranged from 0 to 0.72 mm/hr, while the daily ET varied from 0.0 to
17.0 mm/day. Results show clear relation between land use/land cover and solar
radiation parameters and impact of vegetation cover on the ET values in pixel
wise domain.
KEYWORDS
Landsat-8, remote sensing, evapotranspiration, solar radiation, SEBAL,
NDVI.
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