84th AMS Annual Meeting

Monday, 12 January 2004
Modernization of pre-1948 hourly precipitation records for the contiguous United States
Hall AB
Richard L. Reinhardt, DRI, Reno, NV; and K. T. Redmond, J. A. Ashby, M. Chambers, M. J. Janis, G. Forthun, and M. B. Johnson
A goal of this project is to build a digital dataset of pre-1948 hourly precipitation. A new digital dataset will be composed of at least two historical data sets and will be merged with a post-1948 dataset that is presently in digital format. Hourly precipitation recordings before 1948 were archived under different modernization projects and multiple formats result. Data spanning the period 1830-1941 and consisting of approximately 600 stations were compiled under a WPA project. While most of the archived records contained observations taken in the end of the period, 82 station-records contained observations beginning before 1900. This paper describes the process of building an historical dataset from 87 rolls of microfilm that were imaged and keyed by a federal contractor. Though the contractor produced a rough inventory, it was unknown how much data were hourly, 6-hourly, 12-hourly, or daily. Geographic coordinates and station identifiers other than a city name were not available. The location of each station will be compared with the closest NWS Cooperative Weather Service station and an appropriate station number will be assigned. These data will be quality assured and converted to a standard TD3240 archive format. Additional hourly precipitation data from 1930 through 1948 was archived in a set of books known as the Hydrologic Bulletin. The exact number of stations in a microfilm archive of these books is unknown, but efforts are underway by a federal contractor to index and key-enter digital images of these books. In preparation for keying these data: station history information and a master station list including station name, state, and COOP station number will be compiled; and a keying format that reflects the primary format of the Hydrological Bulletins will be developed. These data will be quality assured and converted to a standard TD3240 archive format. Methods to merge these datasets with the existing digital datasets will be explored.

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