Hourly observations taken by U.S. Air Force personnel at bases in the United States and around the world. Foreign observations concentrated in the Middle East and Japan. Stations assigned WBAN numbers. Original forms sent from the Air Force to NCDC by agreement and stored in the NCDC archives.
In the late 1990s NCDC realized the need to host digital images of weather and climate records on the internet. As a result, EV2 was developed as a key system for providing access to the millions of original source data images in the NCDC archives. With its upload and index capability, EV2 also enables the continuation of NCDC's commitment to make more of its weather and climate data available online so that users across the world can view climate and weather records held in the NCDC archives.