Detection of large-scale forest canopy change in pan-tropical humid forests 2000-2009 with the SeaWinds Ku-band scatterometer

Abstract

We analyzed the 10-year record (1999–2009) of SeaWinds Ku-band microwave backscatter from humid tropical forest regions in South America, Africa, and Indonesia/Malaysia. While backscatter was relatively stable across much of the region, it declined by 1–2 dB in areas of known large-scale deforestation, and increased by up to 1–2 dB in areas of secondary forest or plantation forest growth and in major metropolitan areas. The reduction in backscatter over 142 18.5 km × 18.5 km blocks of tropical forest was correlated with gross forest cover loss (as determined from Landsat data analysis) (R = −0.78); this correlation improved when restricted to humid tropical forest blocks in South America with high initial forest cover (R = −0.93, n = 22). This study shows that scatterometer-based analyses can provide an important geophysical data record leading to robust identification of the spatial patterns and timing of large-scale change in tropical forests. The coarse spatial resolution of SeaWinds (∼10 km) makes it unsuitable for mapping deforestation at the scale of land-use activity. However, due to a combination of instrument stability, sensitivity to canopy change and insensitivity to atmospheric effects, and straight-forward data processing, Ku-band scatterometery can provide a fully independent assessment of large-scale tropical forest canopy dynamics which may complement the interpretation of higher resolution optical remote sensing.

Department

Earth Sciences, Earth Systems Research Center

Publication Date

2-5-2012

Journal Title

IEEE Transactions on Geoscience and Remote Sensing

Publisher

IEEE

Digital Object Identifier (DOI)

10.1109/TGRS.2011.2182516

Document Type

Article

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