Most current digital archives of hourly surface airways observations extend back only to 1948. However, meteorologists and climatologists at the National Climatic Data Center (NCDC) and Northeast Regional Climate Center (NRCC) are making pre-1948 digital hourly data available online as part of the Climate Database Modernization Program. Users can find, retrieve and display data using a web-based image retrieval system called WSSRD (Web Search Store Retrieve Display). In order for data to be useful for interpretive analysis and comparison, the images must have all information keyed into a computer database. This keying is in progress and a few of the priority stations will become available by 2003 with completion possibly by 2007.

Quality control of the keyed data is essential. NCDC meteorologists review the online images to ensure that the correct station and date information are assigned to each image. Next, a team of data entry specialists converts the observations from the images into text data, using keying formats developed at NCDC. These new data sets are then subjected to rigorous quality control algorithms, developed at NRCC, that perform checks against limits and for internal and temporal consistency. These algorithms will be presented. Finally, these data are converted to the NCDC Integrated Surface Hourly format prior to loading to the Climate Data On-line (CDO) system at NCDC.

Climatologists, meteorologists, and scientists in many related fields will benefit from these historical datasets. An immediate application of this database is found in the field of fire weather. Hourly humidity, wind and temperature data extracted from this database can be used in conjunction with the monthly Palmer Z index data to construct a Fire Weather Index spanning the 20th Century. An example of this will be given.