Warsaw University of Life Sciences - SGGW
Validation of Landsat derived LAI and interception storage capacity for Wetlands Derivation from the Landsat 7 NDVI and ground truth validation of LAI and interception storage capacity for Wetland Ecosystems in Biebrza Valley, Poland. Joanna Suligaa, J. Chormański b, S. Szporak-Wasilewska b, M. Kleniewska b, T. Berezowski a, b, A. van Griensven a, c, B. Verbeiren a a.
Dept. of Hydrology and Hydraulic Engineering, Vrije Universiteit Brussel b. Dept. of Hydraulic Engineering, Warsaw University of Life Sciences c. UNESCO-IHE Institute for Water Education
Results: Remote sensing
Introduction
Site 1
Wetlands due to providing a wide range of ecosystems services are very valuable
Site 1
however there is a significant lack of literature data available for calibration and validation. Remote sensing is an undeniably useful for spatial analysis however
Research sites:
requires validation. Therefore a field experiment for interception was designed to
Site 1: Rogożyn Nowy
improve an estimation of this parameter and fill the gap of missing data for wetlands. Aquired data migh be also used for hydrological modelling. The study area, dominated
Site 2
Site 2
Site 2: Szuszalewo
by fen, is located in the Biebrza Valley in North – Eastern part of Poland. Studied species:
This research frames within the INTREV and HiWET projects.
Methodology
Site 1 Site 1
GROUND TRUTH MEASUREMENTS 3 measurements campaigns in 2013: 20-25/05; 23-25/06 and 23-25/07 Field measurements: LAI, biomass, vegetation relevés and GPS Field experiment: Interception storage capacity of 8 plant communities weighting fresh sample spraying and weighting (Smin) submerging and −3 weighting (Smax) calculating Interception = mwet − mfresh ∙ n ∙ 10
Site 2
Site 2
P2.
F. ulmaria*
P3.
C. appropinquata*
P6.
C. nigra*
P7.
C. cespitosa
P8.
C. appropinquata
P12. C. elata „*” indicates species
Map calculations based on Landsat 7 image, 21st of June 2013
Site 1
NDVI = NIR − VIS / NIR + VIS LAI = 9,7686 ∙ NDVI − 1,9528
C. cespitosa*
P11. C. rostrata
REMOTE SENSING
NDVI LAI Smax
P1.
Site 1
from managed area (yearly mowing)
Szporak , 2010
2 Smax = 0.935 + 0.498 LAI − 0.00575 LAI Hoyningen – Huene, 1981 Smax = 0.3063 LAI + 0.5753
Gomez et al., 2001
Smax = 1.184 + 0.490 LAI
Gomez et al., 2001
Site 2
Site 2
Results: Field experiment Interception of wetlands vegetation is changing during a season and varies between the species!
Interception Storage Capacity (after submerging) – Smax
Site 1 Site 1
Site 2
Site 2
Future plans: to explore a different types of imagery with higher spatial (e.g. hyperspectral APEX imagery with 2m ground resolution was collected during the summer of 2015) and higher temporal resolution (Proba-V with 100m spatial resolution but a near-daily revisit time).
Mowing has an impact on interception! Two different ways (methods 1 & 2) of averaging number of plants per m2 gave different results!
Conclusions Interception Storage Capacity (after spraying) - Smin
In case of studied species interception is much bigger after submering („false heavy rain”) than after spraying!
contact email:
[email protected]
Plot no. 1 2 3 6 7 8 11 12
Species C. cespitosa* F. ulmaria* C. appropinquata* C. nigra* C. Cespitosa C. Appropinquata C. rostrata* C. Elata
LAI LAI Smax Smax Smax (Landsat7) (measured) (Landsat7) (method 1) (method 2) 3.9 4.3 1.8 0.43 0.32 3.9 5.5 1.8 0.72 0.37 3.9 5.1 1.8 0.46 0.25 3.9 1.8 0.13 0.13 2.9 6.3 1.5 0.24 0.19 2.9 3.1 1.5 0.84 0.42 2.0 1.1 1.2 0.28 0.21 2.0 4.4 1.2 0.46 0.46 R = 0.55 R = 0.07 R = -0.26
Coarse resolution of Landsat image resulted in poor correlations.
