1007 
Table 1. Field Characterization at the FED Experimental Site at Howland, Maine. 
Category 
Type 
Measurement 
Unit 
A 
Meteorological 
- air temperature 
°C 
T 
- wind speed and direction 
m/s 
M 
- barometric pressure 
mmHg 
0 
- precipitation 
cm 
S 
Radiation 
- shortwave irradiance 
w/m2 
P 
- solar zenith angle 
degrees 
H 
- optical depth 
ppm** 
E 
Gas Flux 
- methane 
R 
- carbon dioxide 
E 
- nitrous oxide 
Forest Stand 
- density 
stems/ha 
- height 
m 
- diameter (breast height) 
cm 
-age 
years 
C 
- species composition 
% 
A 
- crown shape, depth, diameter 
m 
N 
- cone angle 
O 
- trunk size and inclination 
m, degrees 
P 
- branch volume, size, angle distribution 
Y 
Needle 
- volume 
- size 
- density 
num/stem cm 
- angle distribution 
degrees 
- age (first or second) 
years 
-reflectance 
% 
- transmittance 
% 
- absorptance 
% 
- water potential 
% 
- chlorophyll (a,b,total) 
mg/g dry 
- anatomy (cell type, cell arrangement) 
- moisture 
% 
- leaf area index 
m2/m2 
Classification 
- drainage class 
- taxonomy 
senes 
Properties 
- dielectric 
- roughness profileB 
cm 
- moisture (gravimetric) 
% 
- temperature 
°C 
- particle size (sand, silt, clay) 
% 
S 
- water potential (at 0.3 and 1.5 MPa) 
% 
0 
Chemistry 
- pH (H2O, KC1, and CaCl2) 
- 
I 
- exchangeable cations (Ca, Mg, Na, K) 
cmol/kg 
L 
- exchangeable acidity 
cmol/kg 
- extractable exchangeable aluminum 
mg/kg 
- cation exchange capacity (sum, effective) 
cmol/kg 
- iron oxide (in pyrophosphate, oxatlate, CBD) 
mg/kg 
- organic carbon 
% 
- total nitrogen 
% 
- heavy metals (Cu, Ni, Mn, Co, Zn, Pb, Cr) 
mg/kg 
- sulfate adsorption isotherms 
ppm SO4 
The AVIRIS (Airborne Visible Infrared Imaging Spectrometer) and ASAS (Advanced Solid-state Array 
Spectroradiometer) are both directed toward more fully exploiting the spectral reflectance properties of terrestrial 
materials in the solar irradiance portion of the spectrum. AVIRIS is primarily directed toward high spectral 
resolution measurements, whereas ASAS concentrates on the anisotropy of surface directional reflectance. The 
AIRSAR (Airborne Synthetic Aperture Radar) was designed to explore multiple frequency, multiple polarization 
active microwave remote sensing.