Photo courtesy Grant Goodge/NCDC
The Integrated Surface Database (ISD) consists of global hourly and synoptic observations compiled from numerous sources, into a single common ASCII format and common data model. ISD was developed as a joint activity within Asheville's Federal Climate Complex. The National Climatic Data Center, with U.S. Air Force and Navy partners, began the effort in 1998 with the assistance of external funding from several sources. ISD integrates data from over 100 original data sources, including numerous data formats which were key-entered from paper forms during the 1950's-1970's timeframe. ISD Version 1 was released in 2001, with Version 2 (additional quality control applied) in 2003. Since 2003, there have been continued incremental improvements in automated quality control software.
The database comprises over 20,000 stations worldwide, with some having data as far back as 1901, though the data show a substantial increase in volume in the 1940's and again in the early 1970's. Currently there are over 11,000 stations "active" and updated daily in the database. Total data volume (uncompressed) is around 500 gigabytes. ISD includes numerous parameters such as wind speed and direction, wind gust, temperature, dew point, cloud data, sea level pressure, altimeter setting, station pressure, present weather, visibility, precipitation amounts for various time periods, snow depth, and various other elements as observed by each station.
Data access includes several methods: FTP, an interactive interface (called Climate Data Online), a GIS services map interface, and various Web Services. Links to the data access points are provided via this web page.