ASSESSING DIFFERING LEVELS OF ICE STORM DAMAGE TO NORTHERN HARDWOOD FOREST CANOPIES USING ADVANCED SOLID-STATE ARRAY SPECTRORADIOMETER ASAS

摘要

In July 1998 the airborne sensor Advanced Solid-State Array Spectroradiometer (ASAS) was used tornrecord hyperspatial, hyperspectral, multiangle imagery for nine ice damaged hardwood sites in New Hampshire. Inrnorder to discriminate differing levels of damage, atmospherically corrected red edge (653-775 nm) radiance valuesrnwere normalized and blue shift was quantified for each target area as the normalized radiance value at 714 nm. Itrnwas determined that: 1) The slope and position of the normalized red edge spectral signatures of undamaged areasrnfor off-nadir views were very strongly correlated to nadir signatures (R 2 = 0.99). View angle, therefore, does notrnsignificantly affect red edge properties. 2) When blue shift measurements of sites from various view angles wererncompared to measurements of percent ice damage to canopies in situ, the nadir view was strongly correlated torndiffering levels of damage (R 2 = 0.66). Off nadir views showed no strong relationship.