370 likes | 614 Views
Leaf Reflectance & Absorption. Reflectance = 1.0 - Absorption . Transmission transient--if not absorbed then reflected . 5880 K. Leaf Spectral Reflectance. Reflectance = 1.0 - Absorption . Specular versus Diffuse Reflectance. Black Spruce Forest. Backward Scatter View.
E N D
LeafReflectance & Absorption Reflectance = 1.0 - Absorption Transmission transient--if not absorbed then reflected 5880 K
LeafSpectral Reflectance Reflectance = 1.0 - Absorption
Black Spruce Forest Backward Scatter View Forward Scatter View
Soil Backward Scatter View Forward Scatter View
Soybean Field Backward Scatter View Forward Scatter View
Bidirectional Reflectance ofBlack Spruce & Jack Pine no shadows in shadow
Maple & Pine reflectancel maple pine
Plant Pigments So, what absorbs in functioning leaves? (Reflectance = 1.0 - Absorption
Liquid Water Absorption Reflectance = 1.0 - Absorption Liquid water in plant leaves completes the absorption picture: leaves must be hydrated for photosynthesis
Leaf Reflectance & Absorption If no absorption, photons can be reflected internally &/or refracted between air (1.0) & hydrated cells (1.33)
Spatial Resolution -- size (1 m, 10 m, 1km) Spectral Resolution -- wavelength(s) Radiometric Resolution -- detail (1oC) Temporal Resolution -- how often Vegetation Remote Sensing
Spectral intervals for studying vegetation--which ones & why nformation all locales, all conditions, etc. vegetation is goal !vive photosynthesis! reduce atmospheric effects to minimize errors Avoid redundancy --keep it simple stupid
In situ measurements at Pawnee National Grasslands, Colorado
Nondestructive Biological Mass (or biomass) Objective Grassland system -- simple, >>herbaceous Plant biomass is source of energy for system Anything is better than clipping!!! Clipping is limited for time & space extrapolations
HP-2100 mini-computer data collection system (circa 1971) 8196 bytes of RAM no disk drive Paper tape input/output 2-step/pass Fortran compiler Control panel assembly language operation Teletype used to punch paper tapes Believe it or not--this was state of the art!
Thorough documentation of every plot, before & after clipping
Summary of r2 values vs. l for visible, a close association of regression significance between reflectancel and leaf water content with chlorophyll a & b (leaf water live veg.)
Ir/red ratio and normalized difference vegetation index [(ir-red)/(ir+red)]
Winter wheat total dry matterSndvi over growing seasonndvi-days
Sndvi vs. dry biomass Sum ndvi x days