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Full catalog/modis-terra-mod09a1
modis-terra-mod09a1·dataset

Clear-sky satellite ground colors, 8-day, 500 m (Terra)

MODIS Terra Surface Reflectance 8-Day L3 Global 500m
land ESA ESA Copernicus active
In plain English

What it measures. It records how much sunlight the land reflects in seven color bands, after stripping out haze, dust, and air-scattering effects. Each pixel is the cleanest, least-cloudy view picked from an 8-day window at 500-meter detail.

How it's made. Produced by ESA Copernicus from NASA's MODIS instrument on the Terra satellite, atmospherically corrected and composited into a Level-3 product.

How & where you'd use it. This is a foundational building block: it feeds many other products like vegetation indices and land-cover maps, and supports general land monitoring. On its own it is a raw-ish reflectance input rather than a finished thematic map.

What's measured

MODISTerraNASASatelliteGlobalImageryOpticalReflectanceSurface Reflectance500mMOD09A1

Coverage & cadence

  • Time span2000-02-18 → ongoing
  • Spatial extent-180, -90, 180, 90

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 MODIS Terra MOD09A1 Version 6.1 product provides atmospherically corrected Surface Reflectance for MODIS Bands 1-7 at 500 m spatial resolution. The reflectance values are corrected for atmospheric effects including gases, aerosols, and Rayleigh scattering. The dataset is produced as an 8-day composite, where for each pixel the most suitable observation is selected from all acquisitions within the compositing period based on criteria such as cloud conditions and solar zenith angle. When multiple observations meet these criteria, the pixel with the lowest value in Band 3 (blue) is selected. The product also includes two quality assurance layers and four observation bands to support data quality assessment and interpretation.

Get the data

copernicus_access.py
# ESA Copernicus Data Space — open STAC API (free account)
from pystac_client import Client

cat = Client.open("https://stac.dataspace.copernicus.eu/v1")
search = cat.search(
    collections=["modis-terra-mod09a1"],   # add _cog or _nc for a format variant
    bbox=(-10, 35, 30, 60),             # your area (W,S,E,N)
    datetime="2024-01-01/2024-12-31",
)
items = list(search.items())            # then read assets with rioxarray / xarray
Browsing the Copernicus STAC is open; downloading bytes needs a free Copernicus Data Space account.