Sentinel-3 images download

This script automates the per-point search and download of ESA Sentinel-3 images.

An interactive documentation can be found on https://s3-loader.readthedocs.io/

A CODECHECK certificate is available confirming that the computations underlying the article could be independently reproduced:

Sources of data:

• Copernicus Open Access Data Hub Service (DHUS) https://scihub.copernicus.eu/dhus (European Space Agency, ESA)
• Level-1 and Atmosphere Archive & Distribution System Distributed Active Archive Center (LAADS DAAC) https://ladsweb.modaps.eosdis.nasa.gov (National Aeronautics and Space Administration, NASA)

Requirements

python -m pip install requests requests library https://requests.readthedocs.io/en/master/user/install/

Credentials

DHUS and DAAC require authorization that should be provided in S3_loader/config.py next to the rest of the code:

AUTH = ('username', 'password')
DAAC_API_KEY = 'very-long-chain-of-characters'  # since some time called API_TOKEN by DAAC

DAAC registration

update: since some time DAAC uses tokens, it is just a different name for API KEY

DAAC_API_KEY can be generated on https://ladsweb.modaps.eosdis.nasa.gov/profiles/#generate-token-modal

Two agreements have to be accepted to activate the DAAC_API_KEY:

1. ESA Sentinel-3 End User License Agreement:
   • navigate to https://urs.earthdata.nasa.gov/profile/edit
   • scroll to the bottom
   • tick "Yes, I Agree to ESA Sentinel-3 End User License Agreement."
2. NASA agreement:
   • navigate to https://ladsweb.modaps.eosdis.nasa.gov/archive/allData/450/
   • click on "S3A_OL_1_EFR"
   • the page will be redirected to log-in

Input:

• product type
• dates of acquisition
• coordinates of a point

See example.py for details

User steps:

1. Query for product names and unique identifiers (uuid)
2. Download of products:
   • online products - direct parallel download from Copernicus Open Access Hub
   • offline products (Long term archive, LTA) - from LAADS DAAC (if available)
3. Extract pixels from loaded images:
   • ESA SNAP with Sentinel-3 toolbox is required for this operation: http://step.esa.int/main/download/snap-download/
   • shapely package (for Windows from wheel is recommended) https://www.lfd.uci.edu/~gohlke/pythonlibs/#shapely
4. Database extras:
   • mark offline (LTA) products
   • mark products available at DAAC
   • set "loaded" to avoid double download

Output:

• SQLite database file with tables:
  1. site: coordinates
     • to keep track of "single coordinates - single database"
  2. products: name, uuid, size:
     • individual table for each product type
• Downloaded products
• Text files with extracted pixels

OLCI level-1: Google Earth Engine alternative

Google Earth Engine can do everything that this package does [pixel extraction], but there is only OLCI level-1 collection available https://code.earthengine.google.com/61fe01512385e06b5bc3f65f78bef692?noload=true

Recommendations

• To open an SQLite database with GUI and export tables as csv you may use https://sqlitebrowser.org
• To download other Sentinel-1 and Sentinel-2 images you may use https://github.com/sentinelsat/sentinelsat
• Images from LTA are also (partially) available through Data and Information Access Services (DIAS) https://www.copernicus.eu/en/access-data/dias

The code was used in (Prikaziuk, Yang en Van der Tol, 2021) https://doi.org/10.3390/rs13061098