Global WELD products now available for 3 years
GeoTiff format products at http://globalweld.cr.usgs.gov
HDF format products at http://globalweld.cr.usgs.gov/collections

Global Long-Term Multi-Sensor Web-Enabled Landsat Data Record
Roy, D.P, Nemani R., Hansen, M.C., funded by NASA NNH12ZDA001N-MEASURES Spring 2013 to 2018

This new MEaSUREs proposal will (1) extend the CONUS and Alaska WELD Earth System Data Record back to 1982 when the first Landsat 30m data started to be acquired and (2) expand the WELD processing to global scale to provide Landsat 30m information for any terrestrial non-Antarctic location for six 3-year epochs spaced every 5 years from 1985 to 2010. Specifically, in collaboration with researchers at NASA AMES and the University of Maryland, the following combined multi-sensor (Landsat 4, 5 TM and 7 ETM+) 30m products will be generated: 1. Weekly, monthly, seasonal and annual products, CONUS and Alaska, 1982 to 2012, defined in the current WELD product Albers projection, generated at the PI's institution; 2. Annual percent land cover and 5-year land cover change products, CONUS, 1985 to 2010, Albers projection, generated at the PI's institution; 3. Monthly global products, for six epochs (1985, 1990, 1995, 2000, 2005, 2010), 36 months per epoch, defined in the MODIS Sinusoidal projection, generated on the NASA Earth Exchange (NEX) supercomputer at NASA AMES; and 4. Global percent land cover and change for each 36 month epoch (1985, 1990, 1995, 2000, 2005, 2010), MODIS Sinusoidal projection, generated on USGS global 30m land cover initiative hardware at the USGS EROS. This proposal directly supports the moderate global spatial resolution data needs of the climate and global change science communities and the needs of the applications community.

The images and animations below show global WELD product prototypes generated on the NASA Earth Exchange (NEX) supercomputer using all the available Landsat 7 ETM+ and Landsat 5 TM images (processed to L1T in support of this project at the USGS EROS). Each 1.35km true color browse pixel was generated from 45 x 45 30m Landsat pixels. We are also developing a global WELD distribution interface under NASA ACCESS funding.

The image below shows an annual (2010 climate year: December 2009 to November 2010) global WELD Top of atmosphere (TOA) true color reflectance product made from >120,000 Landsat 5 Thematic Mapper and Landsat 7 Enhanced Thematic Mapper Plus Level 1T images. It is defined in the MODIS sinusoidal projection.

Global WELD TOA Reflectance Annual
(click for larger image)

The following animated Gifs and images show the 12 monthly Global WELD products for the 2010 climate year (December 2009 to November 2010). Each monthly product is made from Landsat 5 Thematic Mapper and Landsat 7 Enhanced Thematic Mapper Plus Level 1T data (~6000 to ~13000 acquisitions per month). The products are defined in the MODIS sinusoidal projection. Top of atmosphere (TOA) true color reflectance and Normalized Difference Vegetation Index (NDVI) are shown with a fixed logarithmic contrast stretch and the standard MODIS NDVI color palette respectively.

Global monthly 30m WELD TOA Reflectance
(November 2009 to December 2012)

Global monthly 30m WELD TOA NDVI
(November 2009 to December 2012)

Global monthly 30m WELD TOA Reflectance & NDVI
(November 2009 to December 2012)


The following images show the July 2010 monthly global WELD product generated from 12,374 Landsat 7 ETM+ and Landsat 5 TM L1T images.

Global WELD TOA Reflectance July 2010
(click for larger image)

Global WELD TOA NDVI July 2010
(click for larger image)

This web site is hosted at the Geographic Information Science Center of Excellence (GIScCE), South Dakota State University.
The contents of this web site were written by the GIScCE WELD staff. This site was last updated December 4th 2014.