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Description

The Cloud Mask identifies whether pixels are cloud-covered or not. This is important because algorithms to determine cloud properties should only run on cloudy pixels, and other algorithms that require clear-sky pixels need to screen clouds out. In practice, users apply cloud_flag for strict cloud removal and cloud_flag_dilated when they want a conservative mask that reduces cloud-edge artifacts in downstream products (e.g., Rrs, chlorophyll). The CLDMASK is used operationally as the “cloud and cloud-adjacent” screen.
Core geophysical variables in this suite include:
• cloud_flag — Cloud mask (bitmask; identifies cloud-contaminated pixels)
• cloud_flag_dilated — Cloud or cloud-adjacent pixel mask (bitmask; includes surrounding pixels)
• l2_flags — Level-2 Processing Flags (bitmask)

Version Description

Reprocessing of Ocean Color (OC) Datasets

Product Summary

Platforms
PACE
Instruments
OCI
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Location
GLOBAL OCEAN
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2024-03-05 to Present
Data Partner
Ocean Biology Processing Group (OBPG) ,
Ocean Biology Distributed Active Archive Center (OB.DAAC), Global Change Data Center, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA (NASA/GSFC/SED/ESD/GCDC/OB.DAAC)
Concept ID
C3620139782-OB_CLOUD
Data State
ACTIVE
Number of Files/Granules
91165
Processing Level
2
Published
Updated
Science Keywords
Cloud Properties

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

NASA Ocean Biology Processing Group. (2025). PACE OCI Level-2 Regional Cloud Mask Data, version 3.1 [Data set]. NASA Ocean Biology Distributed Active Archive Center. https://doi.org/10.5067/PACE/OCI/L2/CLOUD_MASK/3.1 Date Accessed: 2026-01-24

Documents

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
geophysical_data/cloud_flag Cloud mask Dimensionless int8 -128 0 to 127 N/A
geophysical_data/cloud_flag_dilated Cloud or cloud-adjacent pixel mask Dimensionless int8 -128 0 to 127 N/A
geophysical_data/l2_flags geophysical_data/l2_flags dimensionless int32 -32767 N/A N/A
navigation_data/latitude Latitude degrees_north float32 -32767 -90 to 90 N/A
navigation_data/longitude Longitude degrees_east float32 -32767 -180 to 180 N/A
scan_line_attributes/clat Cnetral Latitude degrees_north float32 -32767 -90 to 90 N/A
scan_line_attributes/clon Central Longitude degrees_east float32 -32767 -180 to 180 N/A
scan_line_attributes/day Scan day days int32 -32767 0 to 366 N/A
scan_line_attributes/elat Ending Latitude degrees_north float32 -32767 -90 to 90 N/A
scan_line_attributes/elon Ending Longitude degrees_east float32 -32767 -180 to 180 N/A
scan_line_attributes/msec Scan time, milliseconds of day milliseconds int32 -32767 0 to 86400000 N/A
scan_line_attributes/scantime Scan Unix time N/A float64 -32767 0 to 10000000000 N/A
scan_line_attributes/slat Starting Latitude degrees_north float32 -32767 -90 to 90 N/A
scan_line_attributes/slon Starting Longitude degrees_east float32 -32767 -180 to 180 N/A
scan_line_attributes/year Scan year years int32 -32767 1900 to 2100 N/A
sensor_band_parameters/FoBar Mean Solar Flux N/A float32 -32767 0 to 250 N/A
sensor_band_parameters/Tau_r Rayleigh Optical Thickness dimensionless float32 -32767 0 to 0.5 N/A
sensor_band_parameters/wavelength wavelengths nm float32 -32767 0 to 20000 N/A
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