ISLSCP Initiative II

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Hydrology, Soils, & Topography Data

Global Total Plant-Available Soil Water Storage Capacity of the Rooting Zone

The data sets describe the geographic distribution of the total plant-available soil water storage capacity of the rooting zone ("rooting zone water storage size") derived using two separate methods and on a 1 degree global grid. Two inverse methods were employed to describe the extent of the rooting zone water storage size. A first method is based on the assumption that vegetation has adapted to the environment such that it makes optimum use of water (Kleidon and Heimann 1998). Using a simulation model of the land surface-vegetative cover, this method is implemented by maximizing absorption of Photosynthetically Active Radiation (PAR), effectively leading to a maximization of evapotranspiration. The second method is based on the assumption that green vegetation indicates sufficient available water for transpiration (Knorr 1997). Rooting zone water storage size is inferred by minimizing the discrepancy of model simulated absorption to satellite-derived absorption
      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.

Data Provider: Axel Kleidon

Data Files (ISLSCP II Disc #1)

Data Set Documentation

Image Viewing Tutorial

File Information

All of the files in the ISLSCP Initiative II data collection are in the ASCII, or text format. The file format consists of numerical fields of varying length, which are delimited by a single space and arranged in columns and rows. The files in this data set are on a 1 degree by 1 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.
      All files are gridded to a common equal-angle lat/long grid, where the coordinates of the upper left corner of the files are located at 180°W, 90°N and the lower right corner coordinates are located at 180°E, 90°S. Data in the files are ordered from North to South and from West to East beginning at 180 degrees West and 90 degrees North. The data files are PKZip compressed.
      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_masked_values_1d.csv : A table of the values in 1) and 2) that have been replaced and/or modified so that the original files match the land/water mask used in this data collection. This file can be used with 1) and 2) to recreate the original files submitted by the Investigator.

Related Pages:
    ISLSCP Initiative II Home
        General Data Overview
            Hydrology Data Overview
                Global Soil Water Storage Capacity of the Rooting Zone

Revision Date: September 2, 2003