Global Crop Rate Data                         99/09/17

Columns:  Grid#, Crop Rate


Li, Y.F., 1999, "Global gridded technical hexachlorocyclohexane usage
inventory using a global cropland as a surrogate", J. Geophys. Res. In
press.

In this paper, a global cropland data set with 1ox1o longitude and latitude
resolution is created which can be used as a surrogate for gridding
agricultural usage of chemicals, such as technical HCH. This data set has
been compiled using an advanced very high resolution radiometer (AVHRR)
global land database available from World Wide Web server for the EROS Data
Center Node at http://edcwww.cr.usgs.gov/landdaac/1KM/
<http://edcwww.cr.usgs.gov/landdaac/1KM/)> .
The global land 1-km database project represents an international effort to
acquire, archive, process, and distribute 1-km AVHRR data of the entire
global land surface in order to meet the needs of the international science
community. Along with data recorded by the National Oceanic and Atmospheric
Administration (NOAA), a network of 29 high-resolution picture transmission
(HRPT) stations has been acquiring daily global land coverage since April 
1,
1992. The six major participants, including NOAA, the European Space Agency
(ESA), the United States Geological Survey (USGS), the National Aeronautics
and Space Administration (NASA), Australia's Commonwealth Scientific and
Industrial Research Organisation (CSIRO), and China's Satellite
Meteorological Center (SMC), coordinate HRPT receiving stations to acquire
and compile the data set.
The global land cover database was developed on a continent-by-continent
basis. Although each data set contains unique elements based on the
geographic aspects of the specific continent, those elements belonging to
crop catalogue are able to be extracted for each 1ox1o longitude and
latitude grid cell, and the ratio between cropland and the total land in
each grid cell is calculated. Figure 1 shows the global cropland intensity
with 1* latitude by 1* longitude resolution. The ranges of cropland rate 
are
from 1% to 100%. The areas with intensities between 80% and 100% include
northern parts of the United States near the Great Lakes, the north, east,
south, and central parts of China, a band along the north border of India,
and most parts of Ukraine. Croplands are distributed over ~14.9% of the
1?x1? latitude/longitude cells of the global grid, representing ~16.4% of
the total land area of the Earth (Antarctica is not included), and 4.4% of
the total global surface area. The cultivated land from Matthews [1983]
shows a different picture. Area with highest intensity (100%) in Matthews'
data [1983] appear in a wide north-south band extending from south central
Canada to the southern border of the United States, in the intensive
rice-growing regions of Southwest and Southeast Asia, and in the wheat
regions of Australia. Cultivated lands are distributed over ~4.8% of the
1?x1? latitude/longitude cells of the global grid, representing ~12.9% of
the total land area of the earth (Antarctica is not included), and 3.4% of
the total global surface area. Comparing the cropland map shown in Figure 1
with the cultivated land map shown in Figure 3 of Matthews [1983], one can
see that almost all croplands in Figure 1 with intensities <20% were 
treated
as zero cultivation intensity in by Matthews [1983]. These areas include
Omen, Yemen, Cyprus, Papua New Guinea, Suriname, Kuwait, most parts of
Mongolia, and large areas of Siberia in Russia. This led to improper
distributions of HCHs in data sets presented by Li et al., [1996]. Correct
distributions of HCH usage among these areas are important for the results
of atmospheric models. Therefore the cropland data set shown in Figure 1 is
used in this paper to grid global technical HCH usage since it is a better
surrogate than the cultivated intensity data set compiled by Matthews 
[1983]
to allocate the usage data of pesticides and other chemicals applied in
agricultural land. This cropland data set can be used by both scientific 
and
social communities and is available from World Wide Web server for the
Canadian Global Emissions Interpretation Centre Node at
http://www.ortech.ca/cgeic for public use.


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