Global UltraViolet Imager

Welcome to GUVI!

The Global Ultraviolet Imager (GUVI) is one of four instruments that constitute the TIMED spacecraft, the first mission of the NASA Solar Connections program. The TIMED spacecraft is being built by Johns Hopkins University Applied Physics Laboratory and GUVI is a joint collaboration between JHU/APL and the Aerospace Corporation. TIMED will be used to study the energetics and dynamics of the Mesosphere and lower Thermosphere between an altitude of approximately 60 to 180 kilometers.

What's New!

GUVI products in IDL saveset format (O/N2 and NDP) will be made available in NetCDF format. The O/N2 products are available now. Details are available here.

First observation of water blown into space made with FUV instruments! On 15 January 2022, the Hunga Tonga - Hunga Ha’apai submarine volcano explosion was so violent it blew water into space, where the water was detected as an absorption feature in the Far UV dayglow. More info available here

The thermosphere is the region of Earth’s atmosphere that extends from ∼90 to 500 km. Atmospheric disturbances commonly associated with waves perturb temperatures, densities, and winds in this region. Variability in the thermosphere is important as this altitude range overlaps the low earth orbit region of satellites. Despite its importance, limited global observations of the thermosphere region exist. This study presents a multi-instrument study of atmospheric disturbances in the thermosphere and demonstrates the first use of the Global Ultraviolet Imager for the study of waves in the thermosphere. See Katrina Bossert, Larry J. Paxton, Tomoko Matsuo, Larisa Goncharenko, Komal Kumari, Mark Conde, 2022 "Large-Scale Traveling Atmospheric and Ionospheric Disturbances Observed in GUVI With Multi-Instrument Validations", Geophysical Research Letters, 49, (DOI:10.1029/2022GL099901).

We observe TIMED/GUVI enhancements in the limb 130.4 nm radiances at ∼400 and ∼520 km on the dayside during four intense geomagnetic storms in 2003 and 2004. The enhancements were well correlated with Dst and CHAMP total neutral density at 400 km which represents O density as O is the dominant species at those altitudes. See Yongliang Zhang, Larry J.Paxton, R.Schaefer (2022) "Thermospheric density enhancement and limb O 130.4 nm radiance increase during geomagnetic storms". Journal of Atmospheric and Solar-Terrestrial Physics, 229, 105830.

A new method is developed to separate the ionosphere and thermosphere contributions in the observed 135.6 nm emissions by a global far ultraviolet instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite under a sunlit condition. Y. Zhang *, L.J. Paxton, R. Schaefer, Journal of Geophysical Research: Space Physics, 126 (2021).



  • Instrument Fabrication

  • TIMED Construction