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Product pages » Nadir BRDF Adjusted Reflectance - MODIS, CSIRO/Geoscience Australia algorithm, Australia coverage

Nadir BRDF Adjusted Reflectance - MODIS, CSIRO/Geoscience Australia algorithm, Australia coverage

Last modified by Matt Paget on 2016/03/09 12:23

MOD43 16-Day L3 Australian mosaiced 500m

Link to the data

Overview

MODIS-NBAR-20120222-RGB.jpg

The Bi-directional Reflectance Distribution Function (BRDF) models the anisotropic scattering effects of surfaces under different illumination and observation conditions. In simple terms, BRDF describes mathematically the changes in reflectance that we observe when an illuminated target is viewed from different angles. BRDF enables prediction of surface reflectance as a function of solar and viewing geometry. The BRDF is wavelength dependent and is determined by the structural and optical properties of the surface. These properties include shadowing, multiple scattering, transmission, reflection, and absorption and emission by surface elements.

The high temporal frequency and large area coverage of MODIS make it well suited to determine the land surface BRDF properties from multi-date observations that are useful for time series analyses which need to account for observations that have different sensor/solar geometries. The BRDF parameters derived from the BRDF fitting can be inverted to predict what reflectance should be in a given sensor/solar geometry. This allows prediction of reflectance for nadir observations at a mean solar zenith angle over the 16 days period to generate Nadir BRDF adjusted reflectance (NBAR) products.

MODIS NBAR products are operationally produced from 16 days of registered, multi-band, atmospherically corrected surface reflectance data from the MODIS instrument aboard the Terra and Aqua satellite at a 500m spatial resolution. Geoscience Australia use Direct Broadcast MOD43 package from Boston University to generate NBAR composite products. In addition to the NBAR composite products, the BRDF parameters for each band, the ancillary and band quality information are also provided for customer download.

Key specifications

Spatial resolution500 metres
Spatial coverageContinental Australia
Temporal resolution4 days
Temporal coverageFebruary 2000 to present
Sensor & platformMODIS TERRA
CustodianGeoscience Australia and CSIRO
VersionCollection 5
AlgorithmMCD43a4 


Background

Overview

An overview of this product is provided at GA MODIS product web page

Algorithm

An overview of the MCD43A4 version 5 algorithm can be found here MCD43A4 documentation

Other specifications TBA

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Created by Matt Paget on 2012/03/21 09:56

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