Tracking of known problems and subsequent fixes is an important issue for MODIS data users. This page will act as a repository of all known MODIS Atmosphere Data Product problems, as well as how to determine the problematic version (and the fixed version) of the HDF data -- therefore data users should check this page for updates regularly. Data Users unfamiliar with how to properly track problems and fixes by determining the version of their downloaded HDF files should refer to the documentation in the Introduction sublink (the top link along the LHS of this page).
Note that a checkmark (✔) in the tables below means Data Issue or Quality Statement applies. A blank means it's been fixed or does not apply.
Eight Day Data Issues: Table of Contents & Anchor Links
(Note: Anchor Links point to a specific place within this page.)
| Collection/Platform where Issues Apply | ||||||
|---|---|---|---|---|---|---|
| Issue | Impact |
C6.1/Terra |
C6.1/Aqua |
C6.0/Terra |
C6.0/Aqua |
|
| #1. Input L2 Problems propagate downstream |
L |
✔ |
✔ |
✔ |
✔ |
|
| #2. CT Day Granules misplaced to Night |
L |
✔ |
✔ |
✔ |
✔ |
|
| #3. 1km CTP Low Ocean in December |
M |
|
|
✔ |
✔ |
|
Daily Data Quality Statements: Table of Contents & Anchor Links
(Note: Anchor Links point to a specific place within this page.)
| Collection/Platform where Quality Statements Apply | ||||||
|---|---|---|---|---|---|---|
| Quality Statement | Impact |
C6.1/Terra |
C6.1/Aqua |
C6.0/Terra |
C6.0/Aqua |
|
| #1. Missing Pixel Count SDS for CTH |
Q |
✔ |
✔ |
✔ |
✔ |
|
Issue #1: Problems in input Aerosol (04_L2), Water Vapor (05_L2), Cloud (06_L2), Atm. Profile (07_L2), and Cloud Mask (35_L2) propagate into downstream products
Description: See the Known Problem pages for the input (upstream) Level-2 products 04_L2 (Aerosol), 05_L2 (Water Vapor), 06_L2 (Cloud), 07_L2 (Profiles), and 35_L2 (Cloud Mask) by clicking on the links to the left. Users should make themselves aware of any issues in the upstream data products.
Data Dates Affected: Issues could occur for any date
Affected Platform: Terra and Aqua
Collections Affected: Issues possible in all Collections
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Issue #2: Very Intermittently occurring Cloud Top Property Granules misplaced from Daytime to Nighttime
Description: Very occasionally, a few daytime granules are misplaced to the nighttime SDS's in 06_L2. This misplacement seems to be correlated with satellite maneuvers which occur for very brief periods (minutes) on a one to two month schedule. This problem is isolated to any 06_L2 SDS which has the suffix "_Day" or "_Night" (which corresponds to a few Cloud Top Property parameters). The upshot is for users reading any _Day SDS in L2, there will be a few isolated missing granules, and any user reading any _Night SDS in L2, there could be a few cases where day granules are overlapping the night granules. This is occurring in less than 0.001% of the time. To bypass this issue, users can read the un-aggregated L2 SDS's and do the D/N aggregation using the Cloud Mask D/N Flag if needed.
PGE Versions & Production Dates of Problematic & Corrected Data:
Data Dates Affected: Can occur anytime, but very intermittent and very limited in scope
Affected Platform: Aqua and Terra
Collections Affected: All Collections
Additional Documentation: View PDF (shows how this L2 error impact L3)
Issue #3: Problem in C6.0 1-km Cloud Top Pressure (Low) over Ocean in December
Description: A bug was discovered in the Collection 6.0 1-km cloud top pressure low (low in the atmospheric layer, i.e. close to the Earth's Surface) over ocean algorithm for both Terra and Aqua. Low Atmosphere Cloud Top Pressure (> 600 hPa) retrievals for all oceanic L2 December data are not consistent with those of the other months and are considered to be incorrect. The impact will also be seen in daily, 8-day, and monthly L3 data, where 1km CTP data is ingested, Note that this issue was corrected in Collection 6.1 data.
PGE Versions & Production Dates of Problematic Data:
Data Dates Affected: Decembers from launch through 2016
Affected Platform: Aqua and Terra
Collections Affected: Collection 6.0 only
Quality Statement #1: Pixel Count SDS not defined for Cloud Top Height (CTH)
Description: In D3, E3, and M3, the Pixel Count SDSs for the full swath Cloud Top Height (CTH) are not defined (i.e., are missing); note that the Pixel Count SDSs are defined for the Nadir CTH scalar SDSs (see the figure below). This was an oversight in C6/C6.1 development, and breaks the “SDS inventory symmetry” in L3 where all other Cloud Top Property related parameters have Pixel Count SDSs defined. The missing CTH Pixel Count SDSs are NOT particularly problematic since users can indirectly obtain these counts from the CTH Joint Histograms. The upper bin limit of CTH of 18000 m does capture all the L2 CTH data (which is capped at 18000). This oversight of the missing Pixel Count SDS is expected to be remedied in future Collections.
Data Dates Affected: All Data Dates
Affected Platform: Terra and Aqua
Collections Affected: Collection 6.0 and Collection 6.1