Seasonal effects on the estimation of height of boreal and deciduous forests from interferometric TanDEM-X coherence data

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Researchers

  • Aire Olesk
  • Kaupo Voormansik
  • Tanel Tamm
  • Mart Noorma
  • Jaan Praks

Research units

  • Tartu Observatory
  • University of Tartu

Abstract

The aim of this study is to assess the performance of single-pass X-band bistatic SAR interferometric forest height estimation of boreal and temperate deciduous forests under variable seasonal conditions. For this, twelve acquisitions of single-and dual-polarized TanDEM-X coherence images over 118 forest stands were analyzed and compared against LiDAR forest height maps. Strong correlations were found between interferometric coherence magnitude and LiDAR derived forest stand height for pine forests (r2=0.94) and spruce forest (r2=0.87) as well as for deciduous trees (r2=0.94) during leaf-off conditions with temperatures below 0°C. It was found that coherence magnitude based forest height estimation is influenced by leaf-on and leaf-off conditions as well as daily temperature fluctuations, height of ambiguity and effective baseline. These factors alter the correlation and should be taken into account for accurate coherence-based height retrieval. Despite the influence of the mentioned factors, generally a strong relationship in regression analysis between X-band SAR coherence and LiDAR derived forest stand height can be found. Moreover, a simple semi empirical model, derived from Random Volume over Ground model, is presented. The model takes into account all imaging geometry dependent parameters and allows to derive tree height estimate without a priori knowledge. Our results show that X-band SAR interferometry can be used to estimate forest canopy height for boreal and deciduous forests in both summer and winter, but the conditions should be stable.

Details

Original languageEnglish
Title of host publicationEarth Resources and Environmental Remote Sensing/GIS Applications VI
Subtitle of host publicationProceedings of SPIE
EditorsUlrich Michel, Karsten Schulz, Manfred Ehlers, Konstantinos G. Nikolakopoulos, Daniel Civco
Publication statusPublished - 2015
MoE publication typeA4 Article in a conference publication
EventEarth Resources and Environmental Remote Sensing/GIS Applications - Toulouse, France
Duration: 22 Sep 201524 Sep 2015
Conference number: 6

Publication series

NameSPIE - International Society for Optical Engineering. Proceedings
PublisherSPIE
Volume9644
ISSN (Electronic)0277-786X

Conference

ConferenceEarth Resources and Environmental Remote Sensing/GIS Applications
CountryFrance
CityToulouse
Period22/09/201524/09/2015

    Research areas

  • Forest height, radar interferometry, synthetic aperture radar (SAR), TanDEM-X, vegetation mapping, Xband

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