MODIS (Terra + Aqua)

The flagship NASA Earth-observation instrument of the EOS era. 25 years of global observations from two satellites — Terra (morning) + Aqua (afternoon) — at moderate resolution (250m–1km) across 36 spectral bands. Almost everything in land / atmosphere / ocean climate-data products from 2000–present builds on MODIS.

What it sees

• 36 spectral bands, 0.405 µm to 14.385 µm — visible, near-IR, shortwave-IR, thermal-IR.
• Three resolutions: 250 m (2 bands), 500 m (5 bands), 1 km (29 bands).
• ~2330 km swath → covers Earth daily.

Why it matters

• The 25-year continuity is the science — climate-quality vegetation, LST, snow cover, sea ice, ocean color, fire records. Almost every long-term Earth-system analysis from 2000–2025 has a MODIS layer.
• Land Cover (MCD12Q1), NDVI (MOD13Q1), LST (MOD11A1) are the canonical NASA land-cover/dynamics products.
• FIRMS (Fire Information for Resource Management System) is built on MODIS+VIIRS thermal anomaly detection — was NASA’s most-visited site during July 2024 California wildfires.

Where to get the data

• earthaccess Python: short names use MOD* (Terra) or MYD* (Aqua) or MCD* (combined) prefixes
• AppEEARS (LP DAAC tool): area sampling, point sampling, format conversion — easiest for non-programmers
• LAADS DAAC for L1+L2 atmosphere products via ladsweb.modaps.eosdis.nasa.gov
• NASA Worldview for browsing imagery (RGB true-color + many derived layers)

What it enables

• Long-term land-cover change (annual MCD12Q1, 2001–present)
• Vegetation phenology + drought (MOD13Q1 NDVI, 16-day cadence)
• Land-surface temperature anomalies (MOD11A1, daily, climatology)
• Snow cover (MOD10A1, daily)
• Burned area (MCD64A1, monthly)
• Active fires (MOD14/MYD14, instantaneous)
• Cloud + aerosol climatology (MOD06, MOD04)
• Sea-surface temperature (MODIS Aqua thermal bands)
• Ocean color / chlorophyll-a (MODIS Aqua ocean bands)

Gotchas

• Terra is dying. Orbit decay + sensor degradation; expected decommission ~2026. Aqua nominal but degrading. The future is VIIRS (s05 →) — same science continuity, different sensor, slightly different bands.
• Most MODIS L2/L3 is still in legacy HDF-EOS2 / HDF4 formats (not COG, not cloud-optimized). LAADS DAAC began cloud migration in 2024 but format conversion lags.
• Don’t read MOD HDFs with generic netCDF tools — use pyhdf or rioxarray with the right driver, or download via earthaccess which handles the underlying retrieval.
• Terra’s morning crossing and Aqua’s afternoon crossing matter for diurnal-cycle science — don’t blindly average them.
• Some MODIS products are at 5 km, not 250 m — check the user guide.

Related missions

• VIIRS — operational MODIS successor (S-NPP since 2011, JPSS-1/NOAA-20 since 2017, JPSS-2/NOAA-21 since 2022). Continues MODIS’s science.
• Landsat 9 — 30m, complementary resolution; MODIS resolves the planet daily, Landsat resolves the pixel weekly.
• GOES-R / Himawari: geostationary, 10-minute cadence — complements MODIS sun-sync orbit.

Related datasets