Digital Climatic Atlas of Texas - Texas Water Development Board

parameters were not calculated by PRISM during 1890 to 1894. The gridded PRISM
climatic dataset is the product of a multi-year multi-agency effort involving scientists
from NRCS National Water and Climate Center (NWCC) and the Oregon State
University (OSU). PRISM (Parameter-elevation Regressions on Independent Slopes
Model) is an interpolation model developed by NWCC and OSU that uses spatial
information such as elevation, proximity to coast and other information to interpolate the
point measurements of climatic parameters (Daly et al., 2002). Most of the COOP
stations were used in producing these gridded climatic layers and the base data went
through a rigorous QA/QC and data infilling procedures so that the gridded layers are of
highest quality with the best possible estimate (Johns et al., 2003).
The gridded datasets were in the Arc/Info ASCII GRID format and in the
Geographic Coordinate System encompassing the conterminous United States. Hence,
the data were clipped to the spatial extent of Texas and projected to Texas Centric
Mapping System - Albers Equal Area Conic Projection with the projection parameters
given in Table 3 as required by the Texas Administrative Code – Geographic Information
Standards. The unit of the precipitation was millimeters and the temperature was in
degrees Celsius; these were converted to inches and degrees Fahrenheit.
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