The Integrated Global Radiosonde Archive (IGRA) consists of radiosonde and pilot balloon observations from more than 2,800 globally distributed stations. The earliest data date back to 1905, and recent data become available in near real time from about 800 stations worldwide. Observations are available at standard and variable pressure levels, fixed and variable-height wind levels, and the surface and tropopause. Variables include pressure, temperature, geopotential height, relative humidity, dew point depression, wind direction and speed, and elapsed time since launch.
Version 2 is the current version of IGRA. It includes significantly more data than the previous version (IGRA v1), particularly before the 1970s.
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All IGRA-related information is provided in plain-text files. The data in each file are deliberately organized so that both humans and computer programs can easily read and process the information. Alternate formats are not currently available.
Please review the following files prior to downloading the data:
- Readme: Explains and documents the differences between IGRA v1 and v2, available file types, and file locations.
- Station Inventory: This inventory contains the name, country, most recent location, network affiliation, and period of record of each station.
- Country Codes: A list of FIPS 10-4 country codes for countries, dependencies, areas of special sovereignty, and their principal administrative divisions.
Use your browser to explore the folders containing IGRA-related files and download IGRA data one file at a time.
IGRA consists of three components:
- Individual soundings, organized into one file per station
- Monthly means, organized into one file per variable and time of day (0000 and 1200 Coordinated Universal Time)
- Sounding-derived parameters, organized into one file per station
NCEI also provides access to IGRA station metadata that can be helpful for interpreting data. They include current station names and locations as well as information on changes in station location, instrumentation, and observing practices over time, to the extent that they are available.
The IGRA period of record varies for each station and variable. Approximately 800 of the more than 2,800 IGRA stations are currently reporting data. Vertical extent as well as temporal and vertical resolution also vary among stations and over time.
Recommended Uses and Limitations
IGRA can be used as input to air pollution models, for studies of the detailed vertical structure of the troposphere and lower stratosphere, for assessing the atmospheric conditions during a particular meteorological event, and for many other analyses and operational applications. NCEI scientists have applied a comprehensive set of quality control procedures to the data to remove gross errors. However, the data may still include jumps and other discontinuities caused by changes in instrumentation, observing practice, or station location. Users studying long-term trends may prefer to use the NOAA Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC) or one of the available non-NOAA IGRA-derived, homogeneity-adjusted radiosonde datasets.
IGRA Station history information containing Information about changes in station location, instrumentation, and observing practices: For details, see the IGRA readme file.
- Durre, I., Yin, X., Vose, R. S., Applequist, S., & Arnfield, J., 2018: Enhancing the Data Coverage in the Integrated Global Radiosonde Archive, Journal of Atmospheric and Oceanic Technology, 35(9), 1753-1770. doi:10.1175/JTECH-D-17-0223.1.
- Durre, I., R. S. Vose, and D. B. Wuertz, 2006: Overview of the Integrated Global Radiosonde Archive. Journal of Climate, 19, 53-68. doi:10.1175/JCLI3594.1.
- Durre, I., R. S. Vose, and D. B. Wuertz, 2008: Robust automated quality assurance of radiosonde temperatures. Journal of Applied Meteorology and Climatology, 47, 2081-2095. doi:10.1175/2008JAMC1809.1.
- Durre, I., and X. Yin, 2008: Enhanced radiosonde data for studies of vertical structure. Bulletin of the American Meteorological Society, 89, 1257-1262.
- Durre, I., and X. Yin, 2011: Enhancements of the dataset of sounding parameters derived from the Integrated Global Radiosonde Archive. 23rd Conference on Climate Variability and Change, Seattle, WA, 25 January 2011. Available online at https://ams.confex.com/ams/91Annual/webprogram/Paper179437.html. | PDF
- Durre, I., C. N. Williams, Jr., X. Yin, and R. S. Vose, 2009: Radiosonde-based trends in precipitable water over the Northern Hemisphere: An update. Journal of Geophysical Research, 114, D05112, doi:10.1029/2008JD010989.