International Comprehensive Ocean-Atmosphere Data Set (ICOADS)

Project Status


As the result of a US project starting in 1981, available global surface marine data from the late 17th century to date have been assembled, quality controlled, and made widely available to the international research community in products of the Comprehensive Ocean-Atmosphere Data Set (COADS). A new name, International COADS (ICOADS), was agreed in 2002 to recognize the multinational input to the blended observational database and other benefits gained from extensive international collaboration, while maintaining continuity of identity with COADS, which has been widely used and referenced.

The original COADS project, and the continuing US contribution toward the new international database, ICOADS, is the result of a cooperative project between the National Oceanic and Atmospheric Administration (NOAA)--specifically its Earth System Research Laboratory (ESRL), its National Climatic Data Center (NCDC), and the Cooperative Institute for Research in Environmental Sciences (CIRES, conducted jointly with the University of Colorado)--and the National Science Foundation's National Center for Atmospheric Research (NCAR). The NOAA portion of ICOADS is partially funded by the NOAA Climate Program Office (CPO).

ICOADS data are made available in two primary forms:

  • Observations: Surface marine reports from ships, buoys, and other platform types. Each report contains individual observations of meteorological and oceanographic variables, such as sea surface and air temperatures, wind, pressure, humidity, and cloudiness.
  • Monthly summary statistics: Ten statistics (such as the mean and median) are calculated for each of 22 observed and derived variables, using 2° latitude x 2° longitude boxes back to 1800 (and 1°x1° boxes since 1960).

Release 2.5 observations are available for 1662-2007 (261 million individual marine reports), 2° monthly summaries for 1800-2007, and 1° summaries for 1960-2007. In addition, preliminary observations and monthly summaries are available from 2008 forward (updated monthly, and lagging real-time by 2-6 weeks). These data and summary products are drawn from two separate archives:

  1. The most complete and highly processed observations are from the delayed-mode (ICOADS.DM) archive, covering 1662-2007 (note that data from 1662 through the early 1800s are extremely sparse, based on scattered ship voyages; this webpage provides extensive additional information on Release 2.5 data characteristics;).
  2. Less fully processed observations, limited to Global Telecommunications System (GTS) data, are from the real-time (ICOADS.RT) archive. These data were originally processed for March 1997-May 2005 (Overview), subsequently through 2008, and presently are updated monthly in near-real-time.

The observations and monthly summary products currently offered to users are all from ICOADS.DM through the end of 2007. That official Release 2.5 period is followed by preliminary observations and monthly summaries based on the ICOADS.RT archive.

Update plans are as follows:

  1. As resources permit, ICOADS.DM will be enriched with newly available or improved data, and periodically be used to replace the preliminary ICOADS.RT data.
  2. Release (currently 2.5) numbering will refer to the total data and products available to users at a given time (exclusive of the preliminary observational and monthly summary data).
  3. The preliminary IMMA observations and monthly summaries extending past the official end date of Release 2.5 represent an initial step towards updating ICOADS in near-real-time.
  4. In addition, we still have available NCEP Real-time observations (abbreviated in an ascii format) and the associated ICOADS-like 2° summaries (two statistics for ten variables, utilizing a somewhat different quality control and data mixture than ICOADS). However, creation of these products is tentatively scheduled to end in January 2011 (i.e. December 2010 is projected to be the last data month available).

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Updated: Jun 27, 2011 10:00:46 MDT
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