PACE OCI¶
This reader handles L1B TOA reflectance and L2 SFREFL surface reflectance. It is not a general reader for every PACE L2 ocean-colour variable.
ds = hp.open("/path/to/PACE_OCI.product.L2.SFREFL.nc")
print(ds.attrs.get("level"), ds.attrs.get("units"))
Spectral organization¶
The L1B route combines blue, red, and SWIR detector arrays, sorts wavelengths, and retains source-band indexing. Bandpass information differs across spectral regions; nominal VNIR widths and available SWIR widths should not be assumed equally precise.
The main variable is named reflectance for both levels, but its physical meaning changes. L1B TOA reflectance must not be analyzed as retrieved land surface reflectance without the appropriate scientific treatment.
Geometry and mapping¶
PACE data are read as a latitude/longitude swath. L1B geometry can supplement L2; scanline summaries or incomplete geometry are not equivalent to a complete angle field. Keep corresponding products available where the workflow needs them.
hp.georeference() has PACE-specific defaults, including a geographic target grid. Choose resolution and footprint handling deliberately; a wide swath and coarse spatial support require different assumptions from a metre-scale airborne line.
Atmospheric and terrestrial use¶
The atmospheric route converts TOA reflectance using its dedicated irradiance/geometry logic and keeps the supported radiative-transfer band grid. Preserve source indices and the output band table. For terrestrial work, also verify cloud, water, mixed-pixel, and surface-product assumptions. A land-oriented product writing values over water does not validate those values for terrestrial methods.