Until recently, high-quality, high-spatial-resolution temperature and
precipitation data sets for the continental United States were available only as climatological means. None existed that represented sequential monthly values over an extended historical period. Such data sets are needed to enable, for example: transient ecological, hydrological, and natural resource modeling for use in global change assessment; analysis of local and regional trends of climate variations; analysis of frequency, duration, and spatial patterns of extreme climatological events; and investigation of relationships between climatological variability and large-scale forcing mechanisms (e.g., ENSO or QBO).
A data set that meets this need is now being developed by Oregon State University (OSU), the National Center for Atmospheric Research (NCAR), the National Climatic Data Center (NCDC), and the USDA Natural ResourcesConservation Service (NRCS). This project is sponsored by the NOAA Climate and Global Change Program, supported by NOAA/NASA joint funding. The objectives of this work are to: (1) produce a high-quality, 100-year data set of monthly min/max temperature and precipitation analyses on a 2.5-min
(~4 km) spatial grid over the contiguous U.S.; and (2) quantitatively
evaluate the ability of this data set to reproduce observed climate trends and variations, especially in remote and mountainous regions of the country. The project combines point (climate) and spatial (terrain) observation systems to create an enhanced data set. NCDC is providing climate station data, including the most recent Historical Climate Network data set and quality-controlled cooperative data. NRCS is providing high-elevation SNOTEL station data, mostly in the western U.S. NCAR is applying statistical techniques to fill in gaps in the station data records to generate a consistent, comprehensive station data set for this century. OSU is using PRISM, a proven, topographically sensitive interpolation technology, to produce 2.5-min gridded coverages for the entire continental U.S. for each calendar month in the 100-year period of record. The resultant data sets will be archived and distributed by NCDC to a wide variety of modelers and researchers around the world.
The first year of work resulted in two products: (1) a preliminary,
serially complete station data set of monthly precipitation, consisting of
about 10,000 stations; and (2) preliminary, 2.5-min resolution sequential monthly precipitation grids over the contiguous U.S. for the period 1948-1994. In year two, the precipitation station data will undergo further QC at NCDC, the station data infilling and mapping work will be redone and extended back to 1895, and work will begin on preparing station data for temperature.