IGRA v2

The Integrated Global Radiosonde Archive version 2 is a global archive of quality-controlled radiosonde observations dating back to the early 1900s. This repository contains code to import the data into MATLAB as a consistently-formatted structure array usable by other functions for plotting and analysis. This code has been tested on MATLAB 2017b+.

General workflow

1. Obtain a data file from the IGRA v2 archive by saving a file from the data/data-por/ directory for data over the historical record or data/data-y2d/ directory for data from the current year only
2. Make a variable filename in MATLAB pointing to the location of the data file
3. Run [v2] = fullIGRAimpv2(filename) to import the file as a structure array
4. Use findsnd to locate a specific date and time

Step by step example

Let's say that we wanted to look at data from 0Z January 1, 2020 at the Upton, NY site.

1. Access the station list file from the IGRA archive and look up Upton, NY. This file tells us that the Upton station is given by code USM00072501.
2. Go to the IGRA v2 archive and download the file with the correct station code, in this case, USM00072501-data.txt.zip
3. Unzip this file. This will produce a file named USM00072501-data.txt
4. Open MATLAB. Make a variable that points to the location of the data file, e.g. filename = '/Users/[USERNAME]/Downloads/USM00072501-data.txt'
5. Run [v2] = fullIGRAimpv2(filename) to import the Upton data as a structure array named v2
6. Run [numdex] = findsnd(2020,1,1,0,v2) to locate the index of the data from 0Z January 1 2020. In this case, the index is 18489.
7. Use this index to access the relevant data in the v2 structure, e.g. v2(18489) will print this data to the command window.

How does this code work?

fullIGRAimpv2 is a simple wrapper for a bunch of smaller functions: importIGRAv2, levfilter, addHeight, and addDewRH.
      importIGRAv2 imports and makes a structure from the data, then applies very basic quality control
      levfilter removes WMO level type 3 data (which is out of order from the other data, and throws off other functions)
      addHeight calculates height with a function that uses the Durre and Yin (2008) equation.
      addDewRH calculates dewpoint and relative humidity when enough information is available.
Help can be obtained for individual functions by using the MATLAB help name command, e.g. help importIGRAv2

Sources and credit

Except when specified elsewhere, code and documentation were written by Daniel Hueholt under the advisement of Dr. Sandra Yuter at North Carolina State University.

Height calculation comes from Durre, I., & Yin, X. (2008). Enhanced radiosonde data for studies of vertical structure. Bulletin of the American Meteorological Society, 89(9), 1257-1262. Retrieved from http://www.jstor.org/stable/26220887

This repository is maintained by Daniel Hueholt. Links in this readme file are active as of October 19, 2022.

Code in this repository is licensed under the GNU General Public License, which is included in the repository as COPYING.txt. The full license can be viewed at gnu.org/licenses/gpl-3.0.en.html.