Science Data Products and Formats

The PACE science data are processed from Level-0 raw data packets to higher-level products following standard definitions of the NASA Earth Science Data Systems (ESDS) Program. All data products above Level-0 are distributed in Network Common Data Form, version 4 (netcdf4), and follow ESDS file structure and meta-data standards. Specifically, all Level-2 products follow the general format of the current standard ocean products produced by NASA’s Ocean Biology Processing Group (OBPG), as described here. Level-2 data have been composited into global daily, 8-day, and monthly Level-3 products. The Level-3 ocean color products follow the standard OBPG format for binned and mapped products. The final format for aerosol and cloud products is TBD.

To support the multiangle polarimeters (MAPs) and the combined use of OCI with the MAP sensors, an additional Level-1C data level has been defined wherein the data from the various views of each MAP are co-registered to a common grid.

All science data files produced from PACE follow the standard naming convention of the Ocean Biology Processing Group. The filename leader is PACE_OCI, PACE_HARP, or PACE_SPEX for OCI, HARP2, and SPEXone, respectively.

Additional details on algorithm methodology and product content can be found in the product ATBDs.

OCI

OCI data products (Level 2 and below) are now available as part of PACE Reprocessing Version 3. Level 1A and Level 1B files are delivered in native 1.2 km resolution, organized into 5 minute granules that span the daylight portion of each orbit (typically nine to ten per orbit). Level 1C products are now provided on a common co-registered grid as defined by the Level 1C format specification, with granularity fully defined and aligned to the same 5 minute cadence. Level 2geophysical products—including ocean color, aerosol, and cloud parameters (e.g. OC_AOP, OC_IOP, OC_BGC, PAR, surface reflectance)—are currently distributed in provisional, diagnostic, or test status and follow OBPG conventions for suite organization at native resolution (~1.2 km) per granule. Format specifications, sample files, and detailed documentation are provided below.

SPEXone

SPEXone data products are now available as part of NASA’s PACE reprocessing. Level-1A and Level-1B files are provided in native swath resolution, with each granule covering a full daylight orbit (~50 minutes). Level-1C products are distributed on a common georeferenced grid as defined in the Level-1C format specification, with the 5-minute granularity. Level-2 aerosol products generated using the RemoTAP algorithm are also available and follow OBPG conventions for Level-3 compositing. Format specifications and sample files for each data level are provided below.

HARP2

HARP2 data products are now available as part of NASA’s PACE Version 3 reprocessing. Level-1A and Level-1B data are provided in native swath resolution and organized into 5-minute granules along the daylight portion of the orbit. Level-1C products are distributed on a co-registered grid as defined in the Level-1C format specification, using the same 5-minute granularity. Level-2 aerosol and cloud products, generated using the FastMAPOL and GPC algorithms, are now being produced and will support future Level-3 daily, 8-day, and monthly composites following OBPG conventions. Updates in V3 include improved calibration and harmonized polarization conventions with SPEXone. Format specifications and sample files are provided below.