The Closed-Loop Ocean Simulation for Evaluation of ocean color retrieval algorithms (CLOSE) Level-1B collection provides simulated PACE OCI top-of-atmosphere observations generated by PyTOAST from the CLOSE model inputs. The files contain top-of-atmosphere reflectances for the blue, red, and shortwave-infrared bands, along with geolocation, viewing geometry, navigation, scan timing, spectral-response, calibration, and quality information. These simulated observations support atmospheric-correction testing and controlled evaluation of ocean-color retrieval algorithms.

Principal variables and supporting data in this collection include:

• rhot_blue — Top-of-atmosphere reflectance for OCI blue bands
• rhot_red — Top-of-atmosphere reflectance for OCI red bands
• rhot_SWIR — Top-of-atmosphere reflectance for OCI shortwave-infrared bands
• qual_blue, qual_red, and qual_SWIR — Spectral-band quality flags
• latitude and longitude — Pixel geolocation
• sensor_azimuth and sensor_zenith — Sensor-viewing geometry
• solar_azimuth and solar_zenith — Solar geometry
• height — Terrain height at pixel locations
• watermask and quality_flag — Surface classification and geolocation quality information
• CCD_scan_angles and SWIR_scan_angles — Instrument scan angles
• att_ang and att_quat — Spacecraft attitude information
• orb_pos and orb_vel — Orbit position and velocity
• sun_ref — Solar reference vectors
• tilt_angle — OCI tilt angle
• time, HAM_side, and scan_quality_flags — Scan-line timing and quality information
• blue_wavelength, red_wavelength, and SWIR_wavelength — Band-center wavelengths
• blue_solar_irradiance, red_solar_irradiance, and SWIR_solar_irradiance — Mean extraterrestrial solar irradiance
• Blue, red, and SWIR bandpass and polarization-coefficient information