Repeated scan times in PACE OCI CLDMASK V3.1 and cloud-mask choice for land smoke
Posted: Wed Sep 09, 2026 8:13 am America/New_York
I am investigating land wildfire-smoke observations and found inconsistent scan-time fields in:
PACE_OCI.20250110T203503.L2.CLDMASK.V3_1.nc
The file is 7,152,211 bytes. My local SHA256 is 79956240771ccbbc385152bc7102194f57be78384385ff2c451c393f5a968dbb.
A second streaming retrieval from the CMR-provided NASA download endpoint on 2026-09-09 returned the identical size and SHA256.
Of 1710 rows, scantime at zero-based rows 30+28k and 31+28k (k=0 to 59) repeats the times at rows 2 and 3 of the same-start-time AOP V3.2 product. The other 1590 scantime values match AOP time exactly. The year/day/msec fields also appear displaced and are not a reliable substitute: their reconstructed time differs from scantime by up to 295.495 seconds. Navigation arrays of the two products are not identical, so I have not copied AOP time into CLDMASK.
Could you confirm whether this is a known issue and identify the appropriate validated time field or reprocessed product?
Separately, I see substantial spatial disagreement between AOP CLDICE and direct CLDMASK cloud_flag over this smoke scene. AOP records an empty cloud_mask_file, cloud_thresh=0.027 and cloud_wave=870. The cloud-mask ATBD discusses thick-smoke overscreening. Is there a recommended procedure for basic/dilated masks in land aerosol applications, and a way to distinguish their intended use from the AOP flag?
I am retaining both products as diagnostics and have not interpreted either as cloud truth or repaired the original files.
PACE_OCI.20250110T203503.L2.CLDMASK.V3_1.nc
The file is 7,152,211 bytes. My local SHA256 is 79956240771ccbbc385152bc7102194f57be78384385ff2c451c393f5a968dbb.
A second streaming retrieval from the CMR-provided NASA download endpoint on 2026-09-09 returned the identical size and SHA256.
Of 1710 rows, scantime at zero-based rows 30+28k and 31+28k (k=0 to 59) repeats the times at rows 2 and 3 of the same-start-time AOP V3.2 product. The other 1590 scantime values match AOP time exactly. The year/day/msec fields also appear displaced and are not a reliable substitute: their reconstructed time differs from scantime by up to 295.495 seconds. Navigation arrays of the two products are not identical, so I have not copied AOP time into CLDMASK.
Could you confirm whether this is a known issue and identify the appropriate validated time field or reprocessed product?
Separately, I see substantial spatial disagreement between AOP CLDICE and direct CLDMASK cloud_flag over this smoke scene. AOP records an empty cloud_mask_file, cloud_thresh=0.027 and cloud_wave=870. The cloud-mask ATBD discusses thick-smoke overscreening. Is there a recommended procedure for basic/dilated masks in land aerosol applications, and a way to distinguish their intended use from the AOP flag?
I am retaining both products as diagnostics and have not interpreted either as cloud truth or repaired the original files.