FPAR

Description

Calculates the fraction of absorbed photosynthetically active radiation.

Parameters

Name	Type	Length	Value range
Input1: Atmospherically corrected RED sensor channel *	Raster port	1 - 1
Input2: Atmospherically corrected NIR sensor channel *	Raster port	1 - 1
Output: Output FPAR channel	Raster port	0 - 1
Parameters for FPAR calculation	Float	0 - 3	10.0 Default: 1.0,0.4,1.0

* Required parameter

Parameter descriptions

Input1: Atmospherically corrected RED sensor channel

Specifies the input image channel that contains the atmospherically corrected red sensor band reflectance image generated by the ATCOR function.

Input2: Atmospherically corrected NIR sensor channel

Specifies the input image channel that contains the atmospherically corrected NIR sensor band reflectance image generated by the ATCOR function.

Output: Output FPAR channel

Specifies the output channel to receive the FPAR image.

If the specified output file is to be created, this parameter defaults to channel 1 in the output file.

Parameters for FPAR calculation

Specifies three parameters for the FPARM calculation using the following equation:

FPARM = c*[1-a*exp(-b*LAI)] 

The maximum value for any of the three parameters is 10.0.

Details

FPAR calculates the fraction of absorbed photosynthetically active radiation (FPARM) image stored in the specified output file.

To run FPAR, you must enter atmospherically corrected red and NIR sensor bands channels (generated using ATCOR).

FPAR uses the following equation to perform the calculation:

FPAR = c*[1-a*exp(-b*LAI)]

where a, b, and c represent the FPARM parameters.

References

The Atmospheric Correction component was produced by PCI Geomatics using algorithms developed by DLR, German Aerospace Research Establishment. The algorithms used in the various programs of the component are based on information from the following papers:

Lanzl, F. and R. Richter. "A Fast Atmospheric Correction Algorithm for Small Swath Angle Satellite Sensors". ICO topical meeting on atmospheric, volume, and surface scattering and propagation, Florence, Italy, August 1991.

Richter, R. "Error Bounds of a Fast Atmospheric Correction Algorithm for the Landsat Thematic Mapper and Multispectral Scanner Bands", Applied Optics, 30, no.30 (1991):4412-4417.

Richter, R. "Model SENSAT: A Tool for Evaluating the System Performance of Optical Sensors", SPIE PROPAGATION ENGINEERING 1312 (1990): 286-297.

Ahern, F.J., P.M. Teillet, and D.G. Goodenough. "Transformation of Atmospheric and Solar Illumination Conditions on the CCRS Image Analysis System". Paper presented at Machine Processing of Remotely Sensed Data Symposium, 1977.

Richter, R. "A Fast Atmospheric Correction Algorithm Applied To Landsat TM Images", Int. J. Remote Sensing, 11, no. 1 (1990): 159-166.

Calculation of FPAR: Wiegand, C.L. et al., Remote Sensing Environment, 33 (1990): 1-16.

Calculation of LAI from vegetation index (SAVI): Choudhury et al., Remote Sensing Environment, 50 (1994): 1-17.