Núñez, P.Á.; Silva, B.; Schulz, M.; Rollenbeck, R. & Bendix, J. (2021): <b>Evapotranspiration estimates for two tropical mountain forest using high spatial resolution satellite data</b>. <i>International Journal of Remote Sensing</i> <b>42</b>(8), 2940--2962.
Resource Description
Title:
Evapotranspiration estimates for two tropical mountain forest using high spatial resolution satellite data
email:
bendix <at> staff.uni-marburg.de
Deutschhausstraße 12
Room No. 02 A 48
35032 Marburg
Faculty of Geography
Germany
Abstract:
Tropical Mountain Forest (TMF) provides important ecological func-<br/>
tions like evapotranspiration (ET) that supplies moisture and energy <br/>
to the atmosphere. ET observations are scarce and difficult to <br/>
accomplish particularly in areas of high heterogeneity where TMF <br/>
are. Remote sensing (RS) allows to quantify and to determine ET <br/>
spatial variation at the landscape level. Detail imaginary improves <br/>
high spatial variability retrieval. Thought the greater detail intro-<br/>
duces cast shadows by trees which hamper image interpretation. <br/>
The objective of this study is to characterize ET estimation for the <br/>
TMF of the southern Ecuadorian Andes by combining meteorologi-<br/>
cal data with high-resolution satellite images. Shadows from high <br/>
resolution images were masked out by applying focal statistics. The <br/>
analysis included two meteorological periods typical of the area; <br/>
a wet period when rain prevails and a dry period when precipitation <br/>
is more sporadic. The reference evapotranspiration (ET0) was calcu-<br/>
lated using the FAO-Penman Montheid method by applying data <br/>
obtained from an automatic weather station. The enhanced vege-<br/>
tation index (EVI) was derived from 2 m resolution WorldView2 <br/>
satellite images. Results showed a lower ET mean value during the <br/>
wet period: 1.54 mm day−1 <br/>
compared to 2.37 mm day−1<br/>
. Two forest <br/>
types, differentiated from its structural composition and topogra-<br/>
phical position (ravine and ridge), marked ET spatial variation. <br/>
Ravine forest that has a more dense and closed canopy showed <br/>
higher ET values for both meteorological conditions. A comparison <br/>
between ET estimations and ET field measurements from <br/>
a scintillometer device showed a good agreement (coefficient of <br/>
correlation r = 0.89) that proves the validity of the method. This <br/>
study demonstrates that the application of high spatial resolution <br/>
improves ET estimation in TMF especially when shadows are <br/>
removed. Also, emphasizes the importance of analysing spatial <br/>
heterogeneity to properly assess ecosystem water flux terms.
Keywords:
| remote sensing | South Ecuador | Evapotranspiration |
Literature type specific fields:
ARTICLE
Journal:
International Journal of Remote Sensing
Volume:
42
Issue:
8
Page Range:
2940--2962
Publisher:
Taylor \& Francis
Metadata Provider:
Individual:
Jörg Bendix
Contact:
email:
bendix <at> staff.uni-marburg.de
Deutschhausstraße 12
Room No. 02 A 48
35032 Marburg
Faculty of Geography
Germany
