Earthdata Forum

Dear Staff,
with my research group we analyse MODIS and VIIRS LANCE-NRT data for heat flux detection and measures(i.e. https://nrt3.modaps.eosdis.nasa.gov/archive/allData/5201/). Since few days (2 at least), we notice on the VJ1IMG product a (possible?) problem on Band I05_IMG (ThermalInfraRed wavelength) give QF (quality flag) of 8 indicating possible corruction on sensor because Temperature_not_Nominal (https://ladsweb.modaps.eosdis.nasa.gov/api/v2/content/archives/Document%20Archive/Science%20Data%20Product%20Documentation/NASA_VIIRS_L1B_UG_August_2021.pdf page 22).
My question is whether the problem is known, and perhaps being resolved, or whether it is related to some change in the definition of the Quality Flag indices and, consequently, is a my fault in discard the image that, in turn, are usable and succesfully processed.
Thanking you in advance for the great work, please let me know, additionally, if there are more update info about this issue or the argument.
Sincerely,
Marco Laiolo, Department of Earth Sciences, University of Turin (Italy).

Dear Marco Laiolo:
That occurs when the calibration team schedules periodic warm‑up cool‑down (WUCD) activities for calibrating the blackbody, which generally last for 2–3 days.
NOAA‑20 (VJ1) VIIRS performed its annual two‑day emissive band calibration (blackbody WUCD test) on 3/3–3/5. NOAA-21 (VJ2) will perform the same activity next week on 3/10. Normally, the temperature‑setting times (hour of the day) are the same for all three VIIRS instruments, with only the start dates differing. The blackbody is expected to be stable at its nominal temperature by 3/5 at 05:00 UTC.