DOI: 10.1016/j.jag.2016.05.008
Scopus记录号: 2-s2.0-84997724686
论文题名: The effect of topographic normalization on fractional tree cover mapping in tropical mountains: An assessment based on seasonal Landsat time series
作者: Adhikari H ; , Heiskanen J ; , Maeda E ; E ; , Pellikka P ; K ; E
刊名: International Journal of Applied Earth Observation and Geoinformation
ISSN: 15698432
出版年: 2016
卷: 52 起始页码: 20
结束页码: 31
语种: 英语
英文关键词: C-correction
; Landsat
; LiDAR
; NDVI
; Reduced Simple Ratio
; Tasseled Cap
Scopus关键词: correction
; digital elevation model
; Landsat
; lidar
; mapping method
; mountain environment
; NDVI
; time series analysis
; topographic effect
; tropical environment
; Kenya
英文摘要: Free archive of georectified and atmospherically corrected Landsat satellite images create a large range of opportunities for environmental research. However, the topographic effects in images are typically normalized regionally by end-users, and it remains uncertain if this procedure is always necessary. Our objective was to assess the effect of topographic normalization on the fractional tree cover (Fcover) modelling in a tropical mountain landscape, in Southeastern Kenya. We carried out topographic normalization by C-correction for all available Landsat images between June 2012 and October 2013, and examined if normalization improves Fcover regressions. The reference Fcover was based on airborne LiDAR data. Furthermore, we tested several vegetation indices and seasonal features (annual percentiles and means), and compared three digital elevation models (DEM). Our results showed that the fit of Fcover models did not improve after topographic normalization in the case of ratio-based vegetation indices (Normalized Difference Vegetation Index, NDVI; Reduced Simple Ratio, RSR) or Tasseled Cap Greenness but improved in the case of Brightness and Wetness, particularly in the period of the lowest sun elevation. RSR was the best vegetation index to predict Fcover. Furthermore, SRTM DEM provided stronger relationship with cosine of the solar incidence angle than ASTER DEM and regional DEM based on topographic maps. We conclude that NDVI and RSR are robust against topographic effects in the tropical mountain landscapes throughout the year. However, if Tasseled Cap indices are preferred, we recommend topographic normalization using SRTM DEM. © 2016 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/80028
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Geosciences and Geography, University of Helsinki, P.O. Box 68, Finland
Recommended Citation:
Adhikari H,, Heiskanen J,, Maeda E,et al. The effect of topographic normalization on fractional tree cover mapping in tropical mountains: An assessment based on seasonal Landsat time series[J]. International Journal of Applied Earth Observation and Geoinformation,2016-01-01,52