The GOES-17 (now GOES-West) ABI has a cooling system issue that results in degraded image quality during certain times of the day. This anomaly was discovered last summer during post-launch testing, and steps have been taken since then (and continue) to optimize ABI performance.
Additionally, CIMSS is working on data fusion techniques to further mitigate the effects (read here and here).
Detailed information about the cooling system issue and how/when it affects GOES-17 imagery can be found here. To summarize:
- Bands impacted: IR bands 8-12 (3 water vapor, cloud top phase, ozone) and bands 15-16 (Dirty and CO2 IR). This issue also affects the RGB’s, derived products, and channel differences that use the impacted channels.
- Bands not impacted: VIS, Near-IR, shortwave IR, and IR window bands
- Time of year of impact: before and after the vernal and autumnal equinoxes.
- Time of day of impact: morning hours, ~0900 UTC – 1700 UTC. Greatest impact around 1300 UTC.
Presently (mid Feb 2019), the degradation of the impacted GOES-17 bands has been apparent, and will continue to worsen through the end of February. Quality will improve in March, before worsening again in April.
GOES-17 low-level (band 10) water vapor imagery from today, 15 Feb (0815 UTC – 1900 UTC) shows the imagery quality degrade, become unusable, and then improve during the overnight/morning hours (Fig 1). In this animation, there is about 4.5 hours (1115 UTC – 1545 UTC) when the imagery is unusable, and about 2 hours each before and after complete loss when the quality is degraded, but still usable. Band 10 (along with Ozone Band 12 and CO2 band 16) experiences the most degradation in image quality as a result of the cooling issue.
Corresponding imagery from IR Window band 13 appears normal, as expected (Fig 2).
Corresponding imagery from the Airmass RGB, which uses three of the channels impacted including band 10, of course shows degradation and loss similar to that of band 10 (Fig 3).
Next, a 4-panel animation comparing the three water vapor channels (all impacted) and the 10.3 um IR channel (not impacted, Fig 4).
Finally, a 24-hr full disk loop (starting 0230 UTC) showing all 16 GOES-17 ABI channels on 15 Feb 2019 (Fig 5). Not bands 1-7 (VIS, near-IR, shortwave IR) and 13-14 (clean IR window) and have no degradation.
Bill Line, NWS