ASTER Polar Surface and Cloud Classification
Version 2.8, [May 2002]

This provisional release provides a pixel level polar surface and cloud classification based upon a supervised neural network classifier. The possible classifications of surface and cloud types are Water, Snow / Ice, Ice cloud, Land, Thin water cloud, Water cloud over water, Sea ice, Water cloud over land and Bare ground / tundra.

Table of Contents

1. Where to get detailed information on this product
2. How to report problems
3. Description of this version
 * Changes
 * Product Quality
 * Problems and limitations
 * Additional information
4. Version history


1. Where to get detailed information on this product

There are several sources of information that users will find useful:

* ASTER Polar Cloud Mask Algorithm Theoretical Basis Document. Describes the algorithm used to create the product. Available at

http://eospso.gsfc.nasa.gov/eos_homepage/for_scientists/atbd/viewInstrument.php?instrument=24

* US ASTER Website. Describes the ASTER instrument, how to obtain data, the various data products that are available, the activities of the US ASTER Science Team, etc.

http://asterweb.jpl.nasa.gov/

* Level 1 product information. Because the Polar Surface and Cloud Classification product is derived from a Level 1 product, understanding the L1 products is useful.

Level 1 ATBD available at 

http://eospso.gsfc.nasa.gov/eos_homepage/for_scientists/atbd/viewInstrument.php?instrument=24

Level 1 User Guide available at 

http://www.science.aster.ersdac.or.jp/en/index.html

2. How to report problems

To report a problem with the product, please send mail to edc@eos.nasa.gov or call EDC DAAC User Services at (605) 594-6116.


3. Description of this version

This provisional release provides a pixel level polar surface and cloud classification based upon a supervised neural network classifier. The possible classifications of surface and cloud types are as follows:

Code Class
1 Water
2 Snow / Ice
3 Ice cloud
4 Land
5 Thin water cloud
6 Water cloud over water
8 Sea ice
12 Water cloud over land
30 Shadow
31 Forest


Changes:

Version 2.6 was released in October 2001 as a Beta Release
Version 2.8 Provisional Release, updated metadata to include code explanations and incorporated improved classifier.


Product quality:

The neural network classifier was trained to 93% overall accuracy. The product has been visually evaluated over a variety of polar scenes with good overall performance. A more objective independent validation is underway.

Problems and limitations:

Currently, only a daytime algorithm is available. The classifier sometimes misclassifies pixels as cloud at high solar zenith angles (> 80). Some thin clouds over ice are not detected. Currently, Aerosols are poorly represented in the training set and may be misclassified as land, ice, or cloud.

4. Version History

Version 2.6, October 2001
Version 2.8, May 2002