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Description

The CLOUD_GPC suite provides cloud properties derived from the GISS Polarimetric Cloud (GPC) algorithm, along with additional variables obtained through combination with the OCI CLOUD suite.

Given the novelty of implementing a polarimetric algorithm on a global scale, note that several experimental variables—particularly those intended for diagnostic purposes and future refinement—are included and may change in subsequent, more mature versions.
Core geophysical variables in this suite include:
• cloud_bow_droplet_effective_radius - Cloud droplet effective radius from Cloud Bow polarimetric retrievals using parametric fitting technique (µm)
• cloud_bow_droplet_effective_variance - Cloud droplet effective variance from Cloud Bow polarimetric retrievals using parametric fitting technique (unitless)
• cloud_bow_fit_correlation - Parametric fitting correlation for Cloud Bow retrievals of droplet radius and variance (unitless)
• cloud_bow_rms - Root-mean-square error for Cloud Bow retrievals of droplet radius and variance (unitless)
• cloud_liquid_index - Index measuring the strength of the primary rainbow in polarized reflectances from liquid cloud droplets (unitless)
• cloud_rft_mode_fraction_0 - Fractional contribution of droplet mode 1 from Rainbow Fourier Transform retrievals (unitless; range: 0–1)
• cloud_rft_mode_fraction_1 - Fractional contribution of droplet mode 1 from Rainbow Fourier Transform retrievals (unitless; 0–1)

Product Summary

Platforms
PACE
Instruments
HARP2
Spatial Extent

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

Location
GLOBAL OCEAN
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2024-02-05 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
C3600170036-OB_CLOUD
Data State
ACTIVE
Number of Files/Granules
1242
Processing Level
3
Published
Updated
Science Keywords
Clouds

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 HARP2 Level-3 Mapped Cloud Optical Properties, GPC Algorithm, version 3.0 [Data set]. NASA Ocean Biology Distributed Active Archive Center. https://doi.org/10.5067/PACE/HARP2/L3M/CLOUD_GPC/3.0 Date Accessed: 2026-04-11

Variables

The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.

For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor Offset
cloud_bow_droplet_effective_radius Cloud droplet effective radius obtained using Cloud Bow. N/A float32 -32767 3 to 53.400001525879 N/A N/A
cloud_bow_droplet_effective_variance Cloud droplet effective variance obtained using Cloud Bow. micron float32 -32767 0.0015000000130385 to 0.5 N/A N/A
cloud_bow_fit_correlation Correlation of data fit to retrieved cloud droplet radius and variance obtained using Cloud Bow. N/A float32 -32767 -1 to 1 N/A N/A
cloud_bow_rms Root mean square of data fit to retrieved cloud droplet radius and variance obtained using Cloud Bow. N/A float32 -32767 0 to 300 N/A N/A
cloud_liquid_index Index indicating the strength of the primary rainbow in the observed polarized reflectances owing to scattering on liquid drops N/A float32 -32767 -10 to 10 N/A N/A
cloud_rft_mode_fraction_0 Cloud droplet modes effective radius from RFT retrievals for mode 0. micron float32 -32767 0 to 100 N/A N/A
cloud_rft_mode_fraction_1 Cloud droplet modes effective radius from RFT retrievals for mode 1. micron float32 -32767 0 to 100 N/A N/A
lat Latitude degrees_north float32 -999 -90 to 90 N/A N/A
lon Longitude degrees_east float32 -999 -180 to 180 N/A N/A
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