Integrated Global Radiosonde Archive (IGRA) Version 2.2 Readme File Last updated: 24 January 2023 --------------------- Notes: --------------------- 1. This readme file is formatted for viewing in a text editor such as Windows Notepad or similar Linux-based editor. 2. The below information applies to versions 2.0 to 2.2 of IGRA. ------------------------------------------------------------------------ TABLE OF CONTENTS ------------------------------------------------------------------------ I. OVERVIEW II. WHAT'S NEW IN IGRA 2.2 III. DOWNLOAD QUICK START IV. CONTENTS OF FTP DIRECTORY V. CONTENTS OF WEB-ACCESSIBLE FOLDER -------------------------------------------------------------------------------- ------------------------------------------------------------------------ I. OVERVIEW ------------------------------------------------------------------------ This file provides guidance for how to navigate the FTP directory for Integrated Global Radiosonde Archive (IGRA). It provides a brief overview of what is new in IGRA 2.2, step-by-step instructions for downloading desired data and metadata, and an explanation of the contents of the directory and all of its subdirectories. The formats of the various types of files available are described in separate documents. As of February 2023, IGRA 2.2 replaces IGRA 2.0 as NCEI's baseline upper-air dataset. Send any feedback to the IGRA Team at ncei.igra@noaa.gov. ----------------------------------------------------------------------- II. WHAT'S NEW IN IGRA 2.2 ------------------------------------------------------------------------ Following is a summary of what is new and different in IGRA 2.2 compared to IGRA 2.0. - The NCEI/NCEP GTS record in Traditional Alphanumeric Code (TAC) has been augmented with reports received in the newer Binary Universal Form for the Representation of meteorological data (BUFR). This allows data in IGRA to remain up-to-date as an increasing number of stations switch to transmitting radiosonde reports via the Global Telecommunication System (GTS). BUFR reports collected at the National Weather Service's Telecommunications Gateway (NWSTG) and at the European Centre for Medium-Range Weather Forecasts (ECMWF) have been added as supplemental sources to the TAC GTS for each station-day for which no TAC GTS reports are available and either NWSTG or ECMWF data are available. The filled-in soundings have been down-sampled from the typically high resolution of native BUFR reports to the standard and significant levels that are consistent with the historical record. For additional details, see the IGRA Product Description Document located in the same folder as this readme file. - The previous Dataset Description (igra2-dataset-description.pdf) has been reworked into a high-level Product Description (igra2-product-description.pdf) and more detailed Product Description Supplement (igra2-product-description-supplement.pdf). - IGRA data can now be accessed in two ways. FTP access continues to be available at https://www.ncei.noaa.gov/pub/data/igra/ (see Section IV below for the file structure). It is best used from Linux consoles or FTP clients as an increasing number of browsers do not support access to FTP. An alternate direct-download location that also works within browsers can be found in the web-accessible folder at https://www.ncei.noaa.gov/data/integrated-global-radiosonde-archive/ (see Section V below). - No changes have been made to the directory structure, file names, or file formats. ------------------------------------------------------------------------ III. DOWNLOAD QUICK START ------------------------------------------------------------------------ Start by downloading "igra2-station-list.txt", which has metadata for all stations in the dataset. You can find this file in the same location where you found this README file. See the next two sections for details on file locations. Then, to find and download the data for a specific station, proceed as follows: - Find the station's name in "igra2-station-list.txt" and note its station identification code (e.g., Key West is "USM00072201"). - Decide which of the following types of data you desire, navigate to the appropriate subdirectory, and download the desired ZIP-compressed data file(s) and associated format documentation. For individual soundings for the full period of record, go to subdirectory data-por and download the file containing the desired station ID in its filename (e.g., USM00072201-data.txt). For individual soundings from this year only, go to the data-y2d/ subdirectory and download the file containing the desired station ID in its filename. For period-of-record sounding-derived moisture, stability, and other parameters, go to subdirectory derived-por/ and download the file whose name contains the desired station ID (e.g., USM00072201-drvd.txt). For monthly means for the full period of record, go to subdirectory monthly-por/ download the file(s) for the desired variable and nominal hour (e.g., temp_00z-mly.txt.zip for 0000 UTC temperature). For monthly means for only the last calendar month, go to monthly-upd/ and download the file(s) for the desired variable and nominal hour. - Uncompress the downloaded file using an uncompressing software (e.g., 7-Zip or winzip under Windows or the "gunzip" command under Linux). ------------------------------------------------------------------------ IV. CONTENTS OF FTP DIRECTORY (ftp.ncei.noaa.gov/pub/data/igra/) ------------------------------------------------------------------------ --------------------------------- Main level (ftp.ncei.noaa.gov/pub/data/igra/): --------------------------------- data/ contains IGRA 2.2 sounding data files. derived/ contains IGRA 2.2 derived sounding parameters. history/ contains IGRA 2.2 station history information. monthly/ contains IGRA 2.2 monthly means v1/related/ contains raw high-resolution BUFR radiosonde data igra2-country-list.txt a list of country codes used in IGRA 2 station identifiers. igra2-list-format.txt the description of the format of the IGRA 2 station list. igra2-product-description.txt provides high-level documentation of IGRA igra2-product-description-supplement.txt provides detailed technical documentation of IGRA igra2-station-list.txt the list of all IGRA 2 stations and their name, location, period of record, and number of soundings igra2-readme.txt this file. igra2-us-states.txt a list of all two-letter state codes shown in the IGRA 2 station list status.txt notes on the current status of IGRA --------------------------------- Subdirectory data/ (pub/data/igra/data/): --------------------------------- data-por/ contains sounding data for the full period of record. data-y2d/ contains sounding data since January 1 of the current or previous year. igra2-data-format.txt is the description of the format of the sounding data files. --------------------------------- Subdirectory derived/ (pub/data/igra/derived/): --------------------------------- derived-por/ contains sounding-derived parameters for the full period of record. igra2-derived-format.txt is the description of the format of the sounding-derived parameter files. --------------------------------- Subdirectory history/ (pub/data/igra/history/): --------------------------------- igra2-metadata.txt is documented station history information for IGRA 2 stations. igra2-metadata-readme.txt is a description of the format and origin of the documented station history information. wmo-history.txt is a description of the format of the WMO instrument code history files. wmo-sonde-history.txt is a list of the radiosonde codes extracted from GTS messages received at NCDC. wmo-wndeq-history.txt is a list of the measurement equipment codes extracted from GTS messages received at NCDC. --------------------------------- Subdirectory monthly/ (pub/data/igra/monthly/): --------------------------------- monthly-por/ contains monthly means for the full period of record. monthly-upd/ contains monthly means for the last available month. igra2-monthly-format.txt is the description of the format of the monthly-mean files. ------------------------------------------------------------------------ IV. CONTENTS OF WEB-ACCESSIBLE FOLDER ------------------------------------------------------------------------ --------------------------------- Main level (www.ncei.noaa.gov/data/integrated-global-radiosonde-archive/): --------------------------------- access/ contains IGRA data files intended for public access archive/ contains IGRA tar files as stored in NCEI's archive doc/ contains documentation files --------------------------------- Essential Metadata and Documentation --------------------------------- doc/igra2-country-list.txt is a list of country codes used in IGRA 2 station identifiers. doc/igra2-list-Format.txt is the description of the format of the IGRA 2 station list. doc/igra2-station-list.txt is the list of all IGRA 2 stations and their name, location, period ofrecord, and number of soundings. doc/igra2-readme.txt is this file. doc/igra2-us-states.txt is a list of all two-letter state codes shown in the IGRA 2 station list. doc/status.txt notes on the current status of IGRA's data/ contains IGRA 2.2 sounding data files. derived/ contains IGRA 2.2 derived sounding parameters. history/ contains IGRA 2.2 station history information. monthly/ contains IGRA 2.2 monthly means online files --------------------------------- For Access to Sounding Data --------------------------------- access/data-por/ contains sounding data for the full period of record. access/data-y2d/ contains sounding data since January 1 of the current or previous year. doc/igra2-data-format.txt is the description of the format of the sounding data files. --------------------------------- Subdirectory derived/ (pub/data/igra/derived/): --------------------------------- access/derived-por/ contains sounding-derived parameters for the full period of record. doc/igra2-derived-format.txt is the description of the format of the sounding-derived parameter files. --------------------------------- For Accessing Monthly Means --------------------------------- access/monthly-por/ contains monthly means for the full period of record. access/monthly-upd/ contains monthly means for the last available month. doc/igra2-monthly-format.txt is the description of the format of the monthly mean files. --------------------------------- For Accessing Station History Information --------------------------------- doc/igra2-metadata.txt is documented station history information for IGRA 2 stations. doc/igra2-metadata-readme.txt is a description of the format and origin of the documented station history information. doc/wmo-history.txt is a description of the format of the WMO instrument code history files. doc/wmo-sonde-history.txt is a list of the radiosonde codes extracted from GTS messages received at NCDC. doc/wmo-wndeq-history.txt is a list of the measurement equipment codes extracted from GTS messages received at NCDC.