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Full catalog/MYD09Q1
MYD09Q1·v061·dataset

True surface color, best-of-week (Aqua, 8-day, 250 m)

MODIS/Aqua Surface Reflectance 8-Day L3 Global 250m SIN Grid V061
land NASA LPCLOUD Level 3 active HDF-EOS2
In plain English

What it measures. This gives the true reflected color of the land in two bands (red and near-infrared) at 250-meter detail, corrected for the atmosphere, with each pixel chosen as the clearest view from an 8-day window.

How it's made. Derived from the MODIS instrument on NASA's Aqua satellite, atmospherically corrected and composited to keep the least-cloudy observation per 8-day period.

How & where you'd use it. Useful for tracking vegetation greenness and land change at fine detail; note that the Aqua instrument's band 6 detectors have largely failed, so users should heed the supplied flags for affected data.

What's measured

LAND SURFACE › SURFACE RADIATIVE PROPERTIES › REFLECTANCE

Coverage & cadence

  • Time span2002-07-04 → ongoing
  • Measured byAqua (MODIS)
  • Processing levelLevel 3
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF-EOS2
  • 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 MYD09Q1 Version 6.1 product provides an estimate of the surface spectral reflectance of Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Bands 1 and 2, corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. Provided along with the 250 meter (m) surface reflectance bands are two quality layers. For each pixel, a value is selected from all the acquisitions within the 8-day composite period. The criteria for the pixel choice include cloud and solar zenith. When several acquisitions meet the criteria the pixel with the minimum channel 3 (blue) value is used. Known Issues * Prior to the Aqua MODIS launch, Band 6 exhibited several anomalous detectors. Band 6 performance degraded seriously after launch and presently a majority of the Band 6 detectors are non-functional. Science users should read and use the non-functional detector flags and decide for themselves the optimum manner to handle non-functional detector "gaps" for their products. For complete information please refer to the [MODIS Characterization Support Team (MCST) website](https://mcst.gsfc.nasa.gov/time-dependent-list-non-functional-or-noisy-detector). * For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=Aqua&as=61).

Get the data

myd09q1_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MYD09Q1",
    version="061",
    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 LPCLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.