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ISLSCP II Total Plant-Available Soil Water Storage Capacity of the Rooting Zone
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Revision date: April 6, 2011


This data set provides two estimates of the geographic distribution of the total plant-available soil water storage capacity of the rooting zone ("rooting zone water storage size") on a 1.0 degree global grid. Two inverse modeling methods were used. The first modeling approach (optimization) was based on the assumption that vegetation has adapted to the environment such that it makes optimum use of water (Kleidon and Heimann 1998). The second method (assimilation) was based on the assumption that green vegetation indicates sufficient available water for transpiration (Knorr 1997). The data set was developed to provide alternative means to describe rooting characteristics of the global vegetation cover for land surface and climate models in support of the ISLSCP Initiative II data collection. There are three files in this data set.

Additional Documentation:

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, it's derivation, acknowledgements, and references provided by the ISLSCP II Data Management Staff is included with this data set as a companion file named  1_root_water_storage_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) [] 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.

Related Data Sets:

Data Citation:

Cite this data set as follows:

Kleidon, A., 2011. ISLSCP II Total Plant-Available Soil Water Storage Capacity of the Rooting Zone. 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 [] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/1006

File Information:

The archived data sets for ISLSCP II have been organized by categories. This data set is in the Hydrology, Soils, and Topography category---- a collection of hydroclimatology and surface elevation data sets.

Data Set Spatial Extent: Global gridded

Westernmost Longitude: -180 W

Easternmost Longitude: 180 E

Northernmost Latitude: 90 N

Southernmost Latitude: -90 S

Projection: Geographic

Data Set Spatial Resolution:  1.0 degree in both latitude and longitude

Data Set Temporal Extent: 1987 through 1988

Data File Format:

The files in this data set are on a 1.0 degree by 1.0 degree grid and contain 360 columns by 180 rows. All values are written as real numbers. Missing values and water bodies are assigned the value of -999 on all layers.

The three files that make up this data set are named as follows:
  1. root_depth_water_assim_1d.asc : Rooting zone water storage (mm H2O) derived from assimilation of NDVI-fPAR and atmospheric forcing data. 1d means a 1degree spatial resolution in both latitude and longitude.
  2. root_depth_water_optim_1d.asc : Rooting zone water storage (mm H2O) derived from optimization of absorbed PAR. 1d means a 1degree spatial resolution in both latitude and longitude.
  3. root_depth_1d.dif : This file contains Lat-Lon coordinates and data for each point in the two original files that differed from the ISLSCP II Land/Sea mask, and thus were removed from the ASCII map files. This file can be used with 1) and 2) to recreate the original files submitted by the Investigator.

Please refer to 1_root_water_storage_doc.pdf and 0_root_water_storage_readme.txt  for a more complete description of the data files and naming conventions.


Kleidon, A.and M. Heimann, 1998. A method of determining rooting depth from a terrestrial biosphere model and its impacts on the global water and carbon cycle.Global Change Biology, 4: 275-286.

Knorr, W., 1997.Satellitengestuetzte Fernerkundung und Modellierung des globalen CO2- Austauschs der Landvegetation: Versuch einer Synthese. PhD Thesis, University of Hamburg, Germany, 193pp. available in English via ISSN 0938-5177.

Data Access:

These data are available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC)  [].

Data Archive Contact Information:

Telephone: +1 (865) 241-3952