Data Set Characteristics:

Area: ~10 degrees x 10 degrees lat/long
File Size: ~1.3 MB
Projection: Sinusoidal
Data Format: HDF-EOS

Dimensions: 2400 x 2400 rows/columns
Resolution: 500 meters 

Science Data Sets (SDS HDF Layers): 1

Science Data Sets

(HDF Layers) 1

UNITS

BIT TYPE

FILL

VALID RANGE

PercentTreeCover

Percent

8-bit unsigned integer

252

0 - 255

Product Description

Proportional estimates of cover are developed from global training data derived using high-resolution imagery. The training data and phenological metrics are used with a regression tree to derive percent cover globally. The model is then used to estimate areal proportions of:

1) life form (proportion of woody vegetation, herbaceous vegetation, or bare ground),
2) leaf type (proportion of woody vegetation that is needleleaf or broadleaf) 

3) leaf longevity (proportion of woody vegetation that is evergreen or deciduous)

The current V004 collection of the yearly MODIS Vegetation Continuous Fields (VCF) product contains only percent tree cover, with the other layers to follow in later releases.

The data layers in the VCF product (MOD44B) are generated on an annual basis from monthly composites of MODIS 500-meter Surface Reflectance data.  Compositing is based on the second darkest albedo to remove clouds and cloud shadow. Bands 1-7 are used to derive metrics for the calculation of percent tree cover.  Any areas of confusion are alleviated using an additional metric derived from the MODIS Surface Temperature product composited to the same 32-day time step.

Inter-annual comparison of the percent tree cover product should be done with extreme caution as there are many reasons for fluctuations in the percentage from year to year.  Until on-going development of a multi-year change product derived from VCF is complete, users interested in change are encouraged to look at the MODIS Vegetative Cover Conversion product.