Hyper-Temporal C-Band SAR for Baseline Woody Structural Assessments in Deciduous Savannas

Remote Sensing

卷:8

Konrad Wessels¹  Gregory P. Asner²  Renaud Mathieu³  Russell Main³  Laven Naidoo³  Waldo Kleynhans⁴ 

[1] Department of Geography, Geomatics and Meteorology, University of Pretoria, Pretoria 0028, South Africa;

[2] Department of Global Ecology, Carnegie Institution for Science, Stanford, CA 94305, USA;

[3] Ecosystems Earth Observation, Natural Resources and the Environment, CSIR, Pretoria 0001, South Africa;

[4] Remote Sensing Research Unit, Meraka Institute, CSIR, Pretoria 0001, South Africa;

关键词: SAR;    ASAR;    hyper-temporal;    C-band;    canopy cover;    canopy volume;    savanna;   

DOI  :  10.3390/rs8080661

来源: DOAJ

【 摘 要 】

Savanna ecosystems and their woody vegetation provide valuable resources and ecosystem services. Locally calibrated and cost effective estimates of these resources are required in order to satisfy commitments to monitor and manage change within them. Baseline maps of woody resources are important for analyzing change over time. Freely available, and highly repetitive, C-band data has the potential to be a viable alternative to high-resolution commercial SAR imagery (e.g., RADARSAT-2, ALOS2) in generating large-scale woody resources maps. Using airborne LiDAR as calibration, we investigated the relationships between hyper-temporal C-band ASAR data and woody structural parameters, namely total canopy cover (TCC) and total canopy volume (TCV), in a deciduous savanna environment. Results showed that: the temporal filter reduced image variance; the random forest model out-performed the linear model; while the TCV metric consistently showed marginally higher accuracies than the TCC metric. Combinations of between 6 and 10 images could produce results comparable to high resolution commercial (C- & L-band) SAR imagery. The approach showed promise for producing a regional scale, locally calibrated, baseline maps for the management of deciduous savanna resources, and lay a foundation for monitoring using time series of data from newer C-band SAR sensors (e.g., Sentinel1).

【 授权许可】

Unknown