Bi-directional Reflectance: Soil Example

Soil under Wheat Canopy on August 13, 1999 (DOY 225)

Click Here to Get Soil Surface Spectral Data for August 13, 1999

Click Here to go to the Sky Condition Figure

The data for both canopy reflected energy and reference panel has been smooth and resampled for every 5 nm from 400 to 1000 nm.  The reference panel data has been corrected for its non-Lambertian properties.  The cell lists the solar zenith angles (degrees) for each suite of measurements.  A suite of measurements includes a beginning and ending reference panel measurements, 11 measurements in the principal plane of the sun (Backscatter to Forescatter: -75, -60, -45,-30,-15, 0, +15, +30,+45,+60,+75 degrees) and 11 measurements in a plane perpendicular to the principal plane of the sun (From the left to the right facing the sun: -75,-60,..,0,...+60,+75 degrees)  File size varies depending on number of solar zenith angles measure and range from 48-126 Kb. Data format explanation.

Sky Conditions: A graph of  photosynthetically active radiation (PAR) measurements in and above the canopy. Incoming (I), Diffuse and Reflected (R) PAR were measured with Li-Cor Quantum sensors. Transmitted (T) and Soil Reflected (SR) PAR were measured with Li-Cor Line Quantum Sensors. Fraction of absorbed PAR (fAPAR) is calculated by (I-R-T+SR)/I.  Listed in each cell is the Total Leaf Area Index (LAI) for the canopy or the type of canopy that was on the soil.  The yellow bars on the graph indicate when bidirectional reflectance data was measured.

Photos: Listed above are links to a collection of photographs from the  view of the SE590 along the principal plane and perpendicular to the principle plane of the sun for the 55 degree solar zenith angle and nadir photographs for each of the other solar zenith angles.