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Description

AER_RTAPLAND provides aerosol and land‐surface properties over land retrieved using the RemoTAP algorithm. Because RemoTAP jointly models surface and atmosphere over land, the suite also provides spectrally resolved land-surface BRDF and BPDF parameters for reflectance and polarization. Typical uses: air-quality and climate studies, aerosol context for ocean-color/land analyses, radiative transfer, and model evaluation.
Core geophysical variables in this suite include:
• alh — Aerosol layer height (km)
• angstrom_440_670 / angstrom_440_870 / angstrom_490_670 — Aerosol Ångström exponents (unitless)
• aot / aot550 / aot_fine / aot_coarse — Aerosol optical thickness (unitless)
• bpdf_scale, ross_thick, li_sparse, snow_coef — BRDF/BDPF kernel coefficients (unitless)
• chla — Chlorophyll-a concentration (mg m⁻³)
• fmf / fvf — Aerosol fine mode fraction and fine mode volume fraction (unitless)
• lidar_bsca_total / lidar_depol_ratio / lidar_ratio — Aerosol lidar diagnostics (sr⁻¹ m⁻¹, unitless)
• mi / mr — Aerosol refractive index (imaginary/real part, unitless)
• reff_fine / reff_coarse — Aerosol effective radius (µm)
• sph — Aerosol spherical fraction (unitless)
• ssa — Aerosol single scattering albedo (unitless)
• vd / veff_fine / veff_coarse — Aerosol volume density (µm³ µm⁻²) and effective variance (unitless)
• waterfrac_inland — Water fraction for inland pixels (unitless)
• wind_speed — Ocean surface wind speed (m s⁻¹)

Product Summary

Platforms
PACE
Instruments
SPEXone
Spatial Extent

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

Location
GLOBAL OCEAN
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
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
C3555839907-OB_CLOUD
Data State
ACTIVE
Number of Files/Granules
29526
Processing Level
2
Published
Updated
Science Keywords
Aerosols ,
Aerosol Particle 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 SPEXone Level-2 Regional Aerosol Optical Properties Over Land, RemoTAP Algorithm, version 3.0 [Data set]. NASA Ocean Biology Distributed Active Archive Center. https://doi.org/10.5067/PACE/SPEXONE/L2/AER_RTAPLAND/3.0 Date Accessed: 2026-04-01

Documents

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
diagnostic_data/aot550_first_guess First guess of aerosol optical thickness at 550 nm N/A float32 -32767 N/A N/A N/A
diagnostic_data/aot550_mode1_first_guess First guess of aerosol optical thickness (mode 1) N/A float32 -32767 N/A N/A N/A
diagnostic_data/aot550_mode2_first_guess First guess of aerosol optical thickness (mode 2) N/A float32 -32767 N/A N/A N/A
diagnostic_data/aot550_mode3_first_guess First guess of aerosol optical thickness (mode 3) N/A float32 -32767 N/A N/A N/A
diagnostic_data/bpdf_scale_first_guess First guess of bi-directional surface polarization distribution function scaling parameter N/A float32 -32767 N/A N/A N/A
diagnostic_data/chi2 Cost function value N/A float32 -32767 N/A N/A N/A
diagnostic_data/chi2_first_guess Cost function value of the first guess N/A float32 -32767 N/A N/A N/A
diagnostic_data/chla_first_guess First guess of Chlorophyll-a concentration mg m^-3 float32 -32767 N/A N/A N/A
diagnostic_data/cloud_fraction The cloud fraction N/A float32 -32767 N/A N/A N/A
diagnostic_data/f_isotropic_first_guess First guess of surface isotropic scaling parameter for each band N/A float32 -32767 N/A N/A N/A
diagnostic_data/iteration Number of iterations N/A int32 -32767 N/A N/A N/A
diagnostic_data/li_sparse_first_guess First guess of bi-directional surface reflectance distribution function li-sparse kernel coefficient N/A float32 -32767 N/A N/A N/A
diagnostic_data/no2 NO2 column density molecules cm^-2 float32 -32767 N/A N/A N/A
diagnostic_data/nview Number of viewing angles N/A int32 -32767 N/A N/A N/A
diagnostic_data/ozone Ozone column density Dobson float32 -32767 N/A N/A N/A
diagnostic_data/quality_flag Quality of retrieved pixels (0: good) N/A int32 -32767 N/A N/A N/A
diagnostic_data/refr_coefs_mode1 Coefficients of components for refractive index (mode 1) N/A float32 -32767 N/A N/A N/A
diagnostic_data/refr_coefs_mode2 Coefficients of components for refractive index (mode 2) N/A float32 -32767 N/A N/A N/A
diagnostic_data/refr_coefs_mode3 Coefficients of components for refractive index (mode 3) N/A float32 -32767 N/A N/A N/A
diagnostic_data/ross_thick_first_guess First guess of bi-directional surface reflectance distribution function ross-thick kernel coefficient N/A float32 -32767 N/A N/A N/A
diagnostic_data/snow_coef_first_guess First guess of bi-directional surface reflectance distribution function snow kernel coefficient N/A float32 -32767 N/A N/A N/A
diagnostic_data/surface_pressure Surface pressure mb float32 -32767 N/A N/A N/A
diagnostic_data/timing Retrieval time per pixel seconds float32 -32767 N/A N/A N/A
diagnostic_data/water_albedo_correction_first_guess First guess of surface water albedo correction term for each band N/A float32 -32767 N/A N/A N/A
diagnostic_data/wind_speed_first_guess First guess of ocean wind speed m/s float32 -32767 N/A N/A N/A
geolocation_data/fracday The fraction in a day N/A float32 -32767 N/A N/A N/A
geolocation_data/height Height meter float32 -32767 N/A N/A N/A
geolocation_data/height_std Height standard deviation meter float32 -32767 N/A N/A N/A
geolocation_data/latitude Latitude degrees_north float32 -32767 N/A N/A N/A
geolocation_data/longitude Longitude degrees_east float32 -32767 N/A N/A N/A
geolocation_data/pixel_id Pixel id N/A int32 -32767 N/A N/A N/A
geolocation_data/relative_azimuth_angle Relative azimuth angle degree float32 -32767 N/A N/A N/A
geolocation_data/scattering_angle Scattering angle degree float32 -32767 N/A N/A N/A
geolocation_data/sensor_zenith_angle Viewing zenith angle degree float32 -32767 N/A N/A N/A
geolocation_data/solar_zenith_angle Solar zenith angle degree float32 -32767 N/A N/A N/A
geolocation_data/utc_date UTC date N/A int32 -32767 N/A N/A N/A
geophysical_data/alh Aerosol layer height km float32 -32767 N/A N/A N/A
geophysical_data/alh_coarse Aerosol layer height (coarse mode) km float32 -32767 N/A N/A N/A
geophysical_data/alh_fine Aerosol layer height (fine mode) km float32 -32767 N/A N/A N/A
geophysical_data/alh_mode1 Aerosol layer height (mode 1) km float32 -32767 N/A N/A N/A
geophysical_data/alh_mode1_uncertainty Uncertainty of aerosol layer height (mode 1) km float32 -32767 N/A N/A N/A
geophysical_data/alh_mode2 Aerosol layer height (mode 2) km float32 -32767 N/A N/A N/A
geophysical_data/alh_mode2_uncertainty Uncertainty of aerosol layer height (mode 2) km float32 -32767 N/A N/A N/A
geophysical_data/alh_mode3 Aerosol layer height (mode 3) km float32 -32767 N/A N/A N/A
geophysical_data/alh_mode3_uncertainty Uncertainty of aerosol layer height (mode 3) km float32 -32767 N/A N/A N/A
geophysical_data/angstrom_440_670 Aerosol Angstrom exponent, 440 to 670 nm N/A float32 -32767 N/A N/A N/A
geophysical_data/angstrom_440_670_uncertainty Uncertainty of aerosol Angstrom exponent, 440 to 670 nm N/A float32 -32767 N/A N/A N/A
geophysical_data/angstrom_440_870 Aerosol Angstrom exponent, 440 to 870 nm N/A float32 -32767 N/A N/A N/A
geophysical_data/angstrom_440_870_uncertainty Uncertainty of aerosol Angstrom exponent, 440 to 870 nm N/A float32 -32767 N/A N/A N/A
geophysical_data/angstrom_490_670 Aerosol Angstrom exponent, 490 to 670 nm N/A float32 -32767 N/A N/A N/A
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