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
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
复制标题
DOI：
10.1016/j.rse.2010.02.022
复制
发表时间：
2011-11-15
影响因子：
13.5
通讯作者：
Meir, P.
中科院分区：
文献类型：
--
作者：
Mitchard, E. T. A.;Saatchi, S. S.;Meir, P.
利用1996年和2007年的卫星L波段合成孔径雷达后向散射数据（分别来自JERS-1和ALOS PALSAR），结合2007年收集的实地数据和后向校准方法，绘制了喀麦隆中部15 000平方公里森林-稀树草原交错带区域的生物量图。雷达后向散射与地上生物量之间的关系很强（ALOS HV与生物量图的r（2）=0.86，40个疑似未发生变化的区域的ALOS衍生生物量与JERS-1 HH的相关r（2）=0.95）。对于ALOS HV数据，与AGB估算相关的均方根误差（RMSE）在AGB 100 Mg ha（-1）的25%之间。变化检测显示，由于疑似毁林和退化，在高生物量森林上AGB显著减少，而在森林-稀树草原边界沿着，特别是在低人口密度地区，生物量显著增加。对误差的分析表明，雷达数据可以探测到森林-稀树草原过渡区广泛AGB类的变化，准确率> 95%。然而，在像素水平上定量评估AGB（单位：Mg ha（-1））的变化将需要具有类似特征的传感器的雷达图像，这些传感器收集多年来同一季节的数据。(C)2011 Elsevier Inc. All rights reserved.
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 AGB100 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.