The objective of this study was to derive continuous fields of vegetation cover from multi-temporal Advanced Very High Resolution Radiometer (AVHRR) data using all available bands and derived Normalized Difference Vegetation Index (NDVI). The continuous fields describe sub-pixel proportions of cover for tree, herbaceous, bare ground and water cover types. For tree cover, additional fields describing leaf longevity (evergreen and deciduous) and leaf morphology (broadleaf and needleleaf) were also generated. The modeling of carbon dynamics and climate require knowing tree characteristics such as these. This data set consists of three zip files provided at three spatial resolutions of quarter, half, and one degree, each containing seven data files in standard ESRI ArcGIS ArcInfo ASCII Grid format for seven land cover classes. This data set describes the geographic distributions of three fundamental vegetation characteristics: tree, herbaceous and bare ground cover. For tree cover, leaf longevity and morphology layers were produced.
This data set is one of the products of the International Satellite Land-Surface Climatology Project, Initiative II (ISLSCP II) data collection which contains 50 global time series data sets for the ten-year period 1986 to 1995. A complete description of the data, their derivation, acknowledgements, and references provided by the ISLSCP II Data Management Staff is included with this data set as a companion file named 1_veg_continuous_fields_doc.pdf.
ISLSCP II is a consistent collection of data sets that were compiled from existing data sources and algorithms, and were designed to satisfy the needs of modelers and investigators of the global carbon, water and energy cycle. The data were acquired from a number of U.S. and international agencies, universities, and institutions. The data and documentation have undergone two peer reviews.
ISLSCP is one of several projects of Global Energy and Water Cycle Experiment (GEWEX) [http://www.gewex.org/] and has the lead role in addressing land-atmosphere interactions -- process modeling, data retrieval algorithms, field experiment design and execution, and the development of global data sets.
Cite this data set as follows:
DeFries, R., and M.C. Hansen. 2009. ISLSCP II Continuous Fields of Vegetation Cover, 1992-1993. In Hall, Forrest G., G. Collatz, B. Meeson, S. Los, E. Brown de Colstoun, and D. Landis (eds.). ISLSCP Initiative II Collection. Data set. Available on-line [http://daac.ornl.gov/] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/931
The archived data sets for ISLSCP II have been organized by categories. This data set is in the vegetation category--a collection of vegetation and albedo data sets.
Data Set Spatial Extent: Global gridded
Western most Longitude: -180 W
Easternmost Longitude: 180 E
Northernmost Latitude: 90N
Southernmost Latitude: -90S
Projection: Geographic
Data Set Spatial Resolution: 1/4, 1/2, and 1 degrees in both latitude and longitude
Data Set Temporal Extent: April 1992 through March 1993
Data Set Temporal Resolution: Yearly
Data File Format:
All of the data files in each data set within the ISLSCP Initiative II data collection are in ESRI ASCII GRID format for ArcInfo. All files are gridded to a common equal-angle lat/long grid. The data files are grouped by spatial resolution. Each file has 6 header metadata rows.
veg_cont_fields_1deg.zip: ncols360, nrows180, xllcorner-180, yllcorner-90 ,cellsize 1, NODATA_value -99
veg_cont_fields_hdeg.zip: ncols 720, nrows 360, xllcorner-180, yllcorner-90, cellsize.5, NODATA_value -99
veg_cont_fields_qdeg.zip: ncols 1440, nrows 720, xllcorner-180, yllcorner-90, cellsize .25, NODATA_value -99
Data Values:
All values are written as floating point values.
Missing values are assigned the value of -999.00 on all data layers.
Missing values over land are assigned the value of -88.
Data file naming conventions are described in the 0_veg_cont_fields_readme.txt
For each spatial resolution there are seven files describing the percentage, from 0 to 100, of the following global continuous fields, and xx is qd, hd, or 1d, denoting a spatial resolution of 1/4, 1/2 or 1 degree, respectively:
| Layer | Description | Filename |
|---|---|---|
| 1 | Bare Cover | bare_percent_xx.asc |
| 2 | Herbaceous Cover | herb_percent_xx.asc |
| 3 | Tree Cover | tree_percent_xx.asc |
| 4 | Water(ancillary data) | no data file provided |
| 5 | Deciduous tree cover | deciduous_percent_xx.asc |
| 6 | Evergreen tree cover | evergreen_percent_xx.asc |
| 7 | Broadleaf tree cover | broadleaf_percent_xx.asc |
| 8 | Needleleaf tree cover | needleleaf_percent_xx.asc |
These data are available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC) [http://daac.ornl.gov].
E-mail: uso@daac.ornl.gov
Telephone: +1 (865) 241-3952