Ocean colour - Sentinel-3 OLCI chlorophyll monthly via openEO¶

The sentinel-3-olci-chlorophyll-monthly recipe loads OLCI Level-2 ocean chlorophyll (neural-net retrieval, CHL_NN) and reduces it to a monthly mean server-side (NetCDF). A starting point for marine productivity and water-quality monitoring. We use a coastal box and one month.

pip install earthlens[openeo]

Setup¶

Imports for the whole notebook in one place: os and pathlib.Path for the credential checks, and the unified EarthLens entry point from earthlens.

In [ ]:

import os
from pathlib import Path

from earthlens import EarthLens

import os from pathlib import Path from earthlens import EarthLens

Credentials¶

openEO authenticates with CDSE via OIDC. This notebook runs the live download for real when credentials are present (env OPENEO_CLIENT_ID / OPENEO_CLIENT_SECRET, or a cached refresh token from a prior interactive login) and prints a skip note otherwise - so it executes cleanly with or without secrets. See the Authentication page.

Detecting available credentials¶

has_openeo_credentials() reports whether any OIDC credential source is configured: a headless client id/secret pair, a refresh token, or a cached ~/.openeo login from a prior interactive sign-in.

In [ ]:

def has_openeo_credentials() -> bool:
    """Whether some openEO OIDC credential source is available."""
    if os.environ.get("OPENEO_CLIENT_ID") and os.environ.get("OPENEO_CLIENT_SECRET"):
        return True
    if os.environ.get("OPENEO_REFRESH_TOKEN"):
        return True
    return (Path.home() / ".openeo").exists()

def has_openeo_credentials() -> bool: """Whether some openEO OIDC credential source is available.""" if os.environ.get("OPENEO_CLIENT_ID") and os.environ.get("OPENEO_CLIENT_SECRET"): return True if os.environ.get("OPENEO_REFRESH_TOKEN"): return True return (Path.home() / ".openeo").exists()

A run-or-skip wrapper¶

run_or_skip() calls facade.download(...) only when credentials exist, otherwise it prints a skip note and returns an empty list. This keeps the notebook executing top-to-bottom with no errors whether or not CDSE OIDC credentials are configured, so the docs build never needs secrets.

In [ ]:

def run_or_skip(facade, **download_kwargs):
    """Run the live download when credentials exist, else print a skip note."""
    if not has_openeo_credentials():
        print(
            "No openEO OIDC credentials found - skipping the live download.\n"
            "Set OPENEO_CLIENT_ID / OPENEO_CLIENT_SECRET (headless) or sign in once\n"
            "interactively (see the Authentication page) to run this cell for real."
        )
        return []
    paths = facade.download(**download_kwargs)
    for path in paths:
        print(path)
    return paths

def run_or_skip(facade, **download_kwargs): """Run the live download when credentials exist, else print a skip note.""" if not has_openeo_credentials(): print( "No openEO OIDC credentials found - skipping the live download.\n" "Set OPENEO_CLIENT_ID / OPENEO_CLIENT_SECRET (headless) or sign in once\n" "interactively (see the Authentication page) to run this cell for real." ) return [] paths = facade.download(**download_kwargs) for path in paths: print(path) return paths

Build the request¶

Construct the EarthLens facade for the openEO backend: the sentinel-3-olci-chlorophyll-monthly recipe over a coastal box (aoi) for July 2023, writing NetCDF to data/openeo-chl.

In [ ]:

facade = EarthLens(
    data_source='openeo',
    dataset='sentinel-3-olci-chlorophyll-monthly',
    variables=[],
    start='2023-07-01',
    end='2023-07-31',
    aoi=[-1.0, 36.0, 4.0, 40.0],
    path='data/openeo-chl',
)

facade = EarthLens( data_source='openeo', dataset='sentinel-3-olci-chlorophyll-monthly', variables=[], start='2023-07-01', end='2023-07-31', aoi=[-1.0, 36.0, 4.0, 40.0], path='data/openeo-chl', )

Inspect the resolved recipe¶

The facade resolves the recipe name to a concrete openEO collection and band list; printing them confirms what will be requested server-side.

In [ ]:

g = facade.datasource._resolved['sentinel-3-olci-chlorophyll-monthly']
print('collection:', g.collection_id, '| bands:', g.bands)

g = facade.datasource._resolved['sentinel-3-olci-chlorophyll-monthly'] print('collection:', g.collection_id, '| bands:', g.bands)

Download (server-side execution)¶

Hand the facade to run_or_skip(): with credentials it executes the monthly-mean reduction on the openEO backend and returns the written NetCDF path(s); without them it prints the skip note and returns an empty list.

In [ ]:

paths = run_or_skip(facade)
paths

paths = run_or_skip(facade) paths