Fresh biomass estimation in heterogeneous grassland using hyperspectral measurements and multivariate statistical analysis

Roshanak Darvishzadeh, Andrew Skidmore, Mojgan Mirzaie, Clement Atzberger, Martin Schlerf

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

Abstract

Accurate estimation of grassland biomass at their peak productivity can provide crucial information regarding the functioning and productivity of the rangelands. Hyperspectral remote sensing has proved to be valuable for estimation of vegetation biophysical parameters such as biomass using different statistical techniques. However, in statistical analysis of hyperspectral data, multicollinearity is a common problem due to large amount of correlated hyper-spectral reflectance measurements. The aim of this study was to examine the prospect of above ground biomass estimation in a heterogeneous Mediterranean rangeland employing multivariate calibration methods. Canopy spectral measurements were made in the field using a GER 3700 spectroradiometer, along with concomitant in situ measurements of above ground biomass for 170 sample plots. Multivariate calibrations including partial least squares regression (PLSR), principal component regression (PCR), and Least-Squared Support Vector Machine (LS-SVM) were used to estimate the above ground biomass. The prediction accuracy of the multivariate calibration methods were assessed using cross validated R2 and RMSE. The best model performance was obtained using LS_SVM and then PLSR both calibrated with first derivative reflectance dataset with R2CV=0.88 & 0.86 and RMSECV=1.15 & 1.07 respectively. The weakest prediction accuracy was appeared when PCR were used (R2CV = 0.31 and RMSECV= 2.48). The obtained results highlight the importance of multivariate calibration methods for biomass estimation when hyperspectral data are used.

Original languageEnglish
Title of host publicationImaging and Geospatial Technology Forum (IGTF 2015)
Subtitle of host publicationASPRS Annual Conference and co-located JACIE Workshop : proceedings
Place of PublicationMaryland, United States
PublisherAmerican Society for Photogrammetry and Remote Sensing
Pages171-177
Number of pages7
ISBN (Electronic)9781510804579
Publication statusPublished - 2015
Externally publishedYes
EventImaging and Geospatial Technology Forum, IGTF 2015 - ASPRS Annual Conference and co-located JACIE Workshop - Tampa, United States
Duration: 4 May 20158 May 2015

Conference

ConferenceImaging and Geospatial Technology Forum, IGTF 2015 - ASPRS Annual Conference and co-located JACIE Workshop
CountryUnited States
CityTampa
Period4/05/158/05/15

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