Earth Data School
About
Full catalog/S3A_SY_2_SYN
S3A_SY_2_SYN·v1·dataset

True surface color and haze over land (Sentinel-3A)

OLCI+SLSTR/Sentinel-3A L2 Surface Reflectance and Aerosol parameters over Land
land NASA LAADS Level 2 active netCDF-4
In plain English

What it measures. Shows the true color and reflectivity of land surfaces after the haze of the atmosphere has been stripped out, plus measurements of the tiny airborne particles (aerosols) that cause that haze.

How it's made. Created by merging readings from two instruments on Europe's Sentinel-3A satellite, one that captures color in many light bands and one that measures surface temperature.

How & where you'd use it. Useful for mapping vegetation, land cover, and air clarity. It is a mid-level processed product that researchers often feed into further land and climate analyses.

What's measured

SPECTRAL/ENGINEERING › INFRARED WAVELENGTHS › INFRARED RADIANCESPECTRAL/ENGINEERING › INFRARED WAVELENGTHS › REFLECTED INFRAREDSPECTRAL/ENGINEERING › PLATFORM CHARACTERISTICSSPECTRAL/ENGINEERING › PLATFORM CHARACTERISTICS › ATTITUDE CHARACTERISTICSSPECTRAL/ENGINEERING › SENSOR CHARACTERISTICS › TOTAL TEMPERATURESPECTRAL/ENGINEERING › VISIBLE WAVELENGTHS › VISIBLE RADIANCEATMOSPHERE › AEROSOLS › AEROSOL OPTICAL DEPTH/THICKNESSATMOSPHERE › AEROSOLS › AEROSOL OPTICAL DEPTH/THICKNESS › ANGSTROM EXPONENT

Coverage & cadence

  • Time span2019-12-17 → ongoing
  • Measured bySentinel-3A (SLSTR, OLCI)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • FormatsnetCDF-4
  • StatusACTIVE

What you can do with it

  • Track deforestation, fire scars and land-cover change
  • Monitor crop and vegetation health (NDVI/EVI)
  • Map how built-up vs. green an area is over time
Official description

The OLCI+SLSTR/Sentinel-3A L2 Surface Reflectance and Aerosol parameters over Land product with shortname S3A_SY_2_SYN, is generated by combining data acquired by the Ocean and Land Colour Instrument (OLCI) and the Sea and Land Surface Temperature Radiometer (SLSTR), on-board SENTINEL-3. The OLCI is a push-broom imaging spectrometer that measures solar radiation reflected by the Earth at a ground spatial resolution of around 300m, over all surfaces, in 21 spectral bands whereas the SLSTR is a dual scan temperature radiometer. The principal objective of SLSTR products is to provide global and regional Sea and Land Surface Temperature (SST, LST) to a very high level of accuracy (better than 0.3 K) for both climatological and meteorological applications. For more information about the instrument and the mission, visit [Sentinel Online](https://sentinel.esa.int/web/sentinel/home). The S3A_SY_2_SYN is a Level 2 product which consist of surface reflectances for all SYN channels and aerosol parameters over Land. There are 29 Measurement Data Files and 9 Annotation Data Files included in this product. All measurement datasets are provided on the OLCI image grid, similar to the one included in the OLCI L1b product. For more information about the product, read the SENTINEL-3 Synergy [User Guide](https://sentinel.esa.int/web/sentinel/user-guides/sentinel-3-synergy)

Get the data

s3a_sy_2_syn_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="S3A_SY_2_SYN",
    version="1",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from LAADS
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.