AIRS/Aqua Observations of Volcanic Emissions
Introduction
This data repository provides access to observations of volcanic emissions of the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. Aqua was launched in May 2002 into a nearly polar, low earth orbit (705 km altitude, 100 min orbit period, 14.4 orbits per day). Aqua is still operating near continuously.
AIRS is an infrared nadir sounder with across-track scanning capabilities. Each across-track scan covers 1780 km of ground distance and consists of 90 footprints. Two adjacent scans are separated by 18 km along-track distance. The footprint size varies between 14 x 14 km2 at nadir and 21 x 42 km2 at the scan extremes. AIRS measurements cover three wavelength bands in the 3.74-15.4 μm infrared spectral range.
Volcanic emissions are detected from AIRS measurements using brightness temperature difference (BTD) methods. Emissions of volcanic sulfur dioxide (SO2) are detected by analyzing a spectral feature in the 7.3 micron waveband. The AIRS channels selected for the detection are most sensitive to SO2 in the upper troposphere and lower stratosphere region. Volcanic ash is detected based on the reverse absorption feature at 8.1 and 9.2 microns. This technique allows to effectively discriminate between ash particles and ice, but cannot be used to discriminate between volcanic ash and desert dust.
Browse images
The browse images provided on this web site show global maps of AIRS/Aqua observations of volcanic ash and SO2. Data are shown separately for 00:00-12:00 and 12:00-24:00 UTC each day.
Data access
The volcanic emission data sets provided on this web site have been created using AIRS/Aqua L1B Infrared (IR) geolocated and calibrated radiances V005 distributed by the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC). Please see the GES DISC website for further information on the AIRS/Aqua operational data products. Note that this data repository provides access to non-operational research data products, which are dedicated to the research on volcanic emissions.
Notification service
An automatic e-mail notification service has been installed to inform registered users about recent observations of SO2 maxima that can be attributed to volcanic eruptions. In case any events are found, status updates will be sent once per day.
Legal notes
The data sets and browse images provided on this site are licensed under a Creative Commons Attribution 4.0 International License. You are free to share the material in any medium or format and adapt it for any purpose, even commercially. You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits. The licensor cannot revoke these freedoms as long as you follow the license terms. The data are distributed in the hope that it will be useful, but without any warranty. Please follow the link to see the terms and conditions of the license:
References
This data repository can be cited via the following doi:
Hoffmann, Lars, "AIRS/Aqua Observations of Volcanic Emissions", https://doi.org/10.26165/JUELICH-DATA/VPHA3R, Jülich DATA, V1, 2021.
Citation, if the data are used in publications:
Hoffmann, L., Griessbach S., Meyer, C. I.: Volcanic emissions from AIRS observations: detection methods, case study, and statistical analysis, Proc. SPIE 9242, Remote Sensing of Clouds and the Atmosphere XIX, and Optics in Atmospheric Propagation and Adaptive Systems XVII, 924214, https://doi.org/10.1117/12.2066326, 2014.
Contact
We encourage any user interested in the data set to contact us for discussions on how you like to use the data. This might help to reduce the risk of mistaken applications and helps us to track the distribution and areas of applications of the data set.
Please do not hesitate to contact us if you have any further questions:
Dr. Lars Hoffmann
Forschungszentrum Jülich
Jülich Supercomputing Centre
52425 Jülich
Germany
e-mail: l.hoffmann@fz-juelich.de
