Measuring biomass changes due to woody encroachment and deforestation/degradation in a forest-savanna boundary region of central Africa using multi-temporal L-band radar backscatter

REMOTE SENSING OF ENVIRONMENT

卷:115

Article

Mitchard, E. T. A.¹  Saatchi, S. S.²  Lewis, S. L.³  Feldpausch, T. R.³  Woodhouse, I. H.¹  Sonke, B.⁴  Rowland, C.⁵  Meir, P.¹ 

[1] Univ Edinburgh, Sch Geosci, Edinburgh EH8 9XP, Midlothian, Scotland

[2] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA

[3] Univ Leeds, Sch Geog, Earth & Biosphere Inst, Leeds LS2 9JT, W Yorkshire, England

[4] Univ Yaounde, Dept Biol, Yaounde, Cameroon

[5] Lancaster Environm Ctr, CEH Lancaster, Lancaster LA1 4AP, England

关键词: ALOS PALSAR;    Aboveground biomass;    Cameroon;    Change detection;    Deforestation;    Degradation;    Ecotone;    Forest-savanna boundary;    JERS-1;    SAR;    Radar;    REDD;    Woody encroachment;   

DOI  :  10.1016/j.rse.2010.02.022

来源: Elsevier

【 摘 要 】

Satellite L-band synthetic aperture radar backscatter data from 1996 and 2007 (from JERS-1 and ALOS PALSAR respectively), were used with field data collected in 2007 and a back-calibration method to produce biomass maps of a 15 000 km(2) forest-savanna ecotone region of central Cameroon. The relationship between the radar backscatter and aboveground biomass (AGB) was strong (r(2)=0.86 for ALOS HV to biomass plots, r(2)=0.95 relating ALOS-derived biomass for 40 suspected unchanged regions to JERS-1 HH). The root mean square error (RMSE) associated with AGB estimation varied from similar to 25% for AGB<100 Mg ha(-1) to similar to 40% for AGB>100 Mg ha(-1) for the ALOS HV data. Change detection showed a significant loss of AGB over high biomass forests, due to suspected deforestation and degradation, and significant biomass gains along the forest-savanna boundary, particularly in areas of low population density. Analysis of the errors involved showed that radar data can detect changes in broad AGB class in forest-savanna transition areas with an accuracy >95%. However, quantitative assessment of changes in AGB in Mg ha(-1) at a pixel level will require radar images from sensors with similar characteristics collecting data from the same season over multiple years. (C) 2011 Elsevier Inc. All rights reserved.

【 授权许可】

Free