Earth Data School
About
Full catalog/modis-aqua-myd09q1
modis-aqua-myd09q1·dataset

Sharper 8-day global land imagery at 250m (Copernicus)

MODIS Aqua Surface Reflectance 8-Day L3 Global 250m
land ESA ESA Copernicus active
In plain English

What it measures. Gives atmospherically cleaned surface colour in the red and near-infrared bands at a sharper 250-metre detail, ideal for seeing vegetation.

How it's made. Captured by the MODIS sensor on NASA's Aqua satellite and merged into 8-day composites that pick the clearest, least cloudy observation per pixel.

How & where you'd use it. Useful for finer-scale vegetation and land monitoring and as input for greenness indices and land-cover analysis.

What's measured

MODISAquaNASASatelliteGlobalImageryOpticalReflectanceSurface Reflectance250mMYD09Q1

Coverage & cadence

  • Time span2002-07-04 → 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 Aqua MYD09Q1 Version 6.1 product provides atmospherically corrected Surface Reflectance for MODIS Bands 1 and 2 at 250 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 satisfy these criteria, the pixel with the lowest value in Band 3 (blue) is selected. The product also includes two quality assurance layers that provide information about data quality and observation conditions.

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-aqua-myd09q1"],   # 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.