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.


GUVI filenames are being changed to handle the larger orbit numbers.
Since TIMED is rapidly approaching the 100000th orbit, we are currently in the process of updating the orbit number field in the names of our files from 5 to 6 characters to handle the larger numbers. Files with the new naming convention and now being made, and older files will be backfilled after reprocessing to the new name format is completed.


The most up to date calibrated products (version 13) are now the default GUVI data products. Details about the changes to the calibration and data products can be found here.

Comparison of GUVI and WACCMX (at 155 km) temperatures on March 16, 2013 at 232 four different longitudes (a) 3°, (b) 180°, (c) 300°, (d) 360°. The feature marked "SAA" in (c) is an artefact created by energetic particles creating detector noise as the spacecraft passes through the South Atlantic Anomaly (SAA). See Zhang, Y., Paxton, L.J., Schaefer, R.K., 2019, "Deriving thermospheric temperature from TIMED/GUVI observations", Journal of Geophysical Research - Space Physics, 124, 5848-5856, (DOI:10.1029/2018JA026379). .

Using the GUVI spectrograph data, the GUVI team was able to extract the 149.3 nm emission line from dayside data. The plot above shows GUVI N-149.3 nm radiance maps during the St. Patrick's day storms of 2013 and 2015. The left panels are from 2013 and the right panels are from 2015. Then the plots are for March 16 (top), 21 (middle) and 28 (bottom). Y. Zhang *, L.J. Paxton, D. Morrison, R. Schaefer, JASTP, 169 (2018) 78-82.


Examples of UV spectrographic emission observed by DMSP F16/SSUSI on (a) 1 January 2017 and (b) 1 July 2017. From left to right, solar zenith angle (black) and solar local time (red), F16 tracks, and observations of OI 130.4, OI 135.6, and LBHS lines at the pierce point of 350 km are shown. The anomalous OI emissions on orbits A and D are indicated by yellow shadings. The black dashed line in the map is the magnetic equator. GUVI and F16/SSUSI are very similar instruments and both are now in spectrograph mode. See Kil, H., Schaefer, R. K., Paxton, L. J., & Jee, G. (2020). "The far ultraviolet signatures of conjugate photoelectrons seen by the Special Sensor Ultraviolet Spectrographic Imager". Geophysical Research Letters, 47, e2019GL086383. (DOI: 10.1029/2019GL086383).


  • Instrument Fabrication

  • TIMED Construction

Latest Results

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