A comparison of forest canopy height estimates derived from SRTM and TOPSAR in the Sierra Nevada of California

摘要

A study was conducted to determine the extent to which data from the 2000 Shuttle Radar Topography Mission (SRTM) could be used to estimate vegetation canopy height in conjunction with an existing bald-Earth DEM provided by the National Elevation Dataset (NED). A densely forested study site with maximum canopy heights reaching 70+ m in the central Sierra Nevada of California was identified based on the availability of suitable field data from within the general mission timeframe. Preliminary work has been conducted to compare C-band SRTM and TOPSAR digital elevation products with canopy height estimates obtained from ground measurements. Results indicate that SRTM data can be successfully correlated via linear regression modeling with ground-measured metrics of vegetation canopy height including median, mean, and maximum height. Maximum canopy height was predicted from SRTM data with an RMSE of 4.9 meters when a minimum of 50 SRTM pixels w as available for averaging This study confirms previous findings, which suggest that after averaging a minimum of 20 SRTM-NED difference pixels to reduce phase noise errors, stable estimates of interferometric mean scattering phase center height can be extracted.