Open-source investigators and geospatial analysts rely primarily on two publicly funded earth observation constellations for environmental monitoring, damage assessments, and infrastructure tracking: the European Space Agency’s Copernicus Sentinel-2 and the NASA/USGS Landsat 9. While both satellite systems orbit the Earth in sun-synchronous trajectories and provide open data, their sensor payloads, ground sample distances (GSD), and spectral coverage serve distinct analytical functions.

This technical guide provides a direct band-by-band spectral comparison matrix, explains when to prioritize Sentinel-2’s 10-meter spatial resolution over Landsat 9’s thermal infrared sensors, and provides ready-to-use band formulas for investigative reporting.

┌────────────────────────────────────────────────────────────────────────┐
│             CORE CONSTELLATION SPECIFICATIONS COMPARISON               │
├────────────────────┬────────────────────┬──────────────────────────────┤
│ PARAMETER          │ COPERNICUS SENTINEL-2 (A/B)│ USGS / NASA LANDSAT 9│
├────────────────────┼────────────────────┼──────────────────────────────┤
│ Primary Sensors    │ MultiSpectral      │ Operational Land Imager 2    │
│                    │ Instrument (MSI)   │ (OLI-2) + TIRS-2 (Thermal)   │
├────────────────────┼────────────────────┼──────────────────────────────┤
│ Visible / NIR Res. │ 10 meters / pixel  │ 30 meters / pixel            │
│                    │ (Bands 2, 3, 4, 8) │ (15m Panchromatic Band 8)    │
├────────────────────┼────────────────────┼──────────────────────────────┤
│ Shortwave IR (SWIR)│ 20 meters / pixel  │ 30 meters / pixel            │
├────────────────────┼────────────────────┼──────────────────────────────┤
│ Thermal Infrared   │ NONE               │ 100 meters / pixel           │
│ Capabilities       │ (Requires Landsat) │ (Bands 10 & 11 TIRS-2)       │
├────────────────────┼────────────────────┼──────────────────────────────┤
│ Temporal Revisit   │ 5 Days             │ 16 Days (8 Days when paired  │
│ (Equator)          │ (Twin satellites)  │ with Landsat 8)              │
├────────────────────┼────────────────────┼──────────────────────────────┤
│ Radiometric Res.   │ 12-bit (4,096 gray)│ 14-bit (16,384 gray levels)  │
└────────────────────┴────────────────────┴──────────────────────────────┘

1. Direct Spectral Band Cross-Reference Matrix

Because Sentinel-2 and Landsat 9 number their spectral bands differently, analysts frequently make errors when translating formulas between sensors. Use this correlation table to ensure accuracy:

┌────────────────────────────────────────────────────────────────────────┐
│             BAND-BY-BAND SPECTRAL EQUIVALENCE MATRIX                   │
├──────────────────────┬──────────────────────┬──────────────────────────┤
│ SPECTRAL REGION      │ SENTINEL-2 (MSI)     │ LANDSAT 9 (OLI-2/TIRS-2) │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ Coastal Aerosol      │ Band 1 (443nm / 60m) │ Band 1 (443nm / 30m)     │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ Blue                 │ Band 2 (490nm / 10m) │ Band 2 (482nm / 30m)     │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ Green                │ Band 3 (560nm / 10m) │ Band 3 (561nm / 30m)     │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ Red                  │ Band 4 (665nm / 10m) │ Band 4 (655nm / 30m)     │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ Vegetation Red Edge  │ Bands 5, 6, 7 (20m)  │ NONE                     │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ Near Infrared (NIR)  │ Band 8 (842nm / 10m) │ Band 5 (865nm / 30m)     │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ Narrow NIR           │ Band 8A (865nm / 20m)│ Band 5 (865nm / 30m)     │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ Water Vapor          │ Band 9 (945nm / 60m) │ Band 9 (1373nm / 30m)    │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ SWIR 1               │ Band 11 (1610nm/ 20m)│ Band 6 (1608nm / 30m)    │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ SWIR 2               │ Band 12 (2190nm/ 20m)│ Band 7 (2200nm / 30m)    │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ Panchromatic         │ NONE                 │ Band 8 (590nm / 15m)     │
├──────────────────────┼──────────────────────┼──────────────────────────┤
│ Thermal Infrared     │ NONE                 │ Band 10 (10.9µm / 100m)  │
│                      │                      │ Band 11 (12.0µm / 100m)  │
└──────────────────────┴──────────────────────┴──────────────────────────┘

2. When to Use Sentinel-2 vs. Landsat 9

Choose Sentinel-2 For:

1. Tactical Urban Infrastructure & Vehicle Dispersal: At 10 meters per pixel, Sentinel-2 can resolve runway extensions, bridge collapses, naval vessel wakes, and large military tent encampments.
2. Rapid Temporal Tracking (5-Day Revisit): Because Sentinel-2 operates as a twin constellation (Sentinel-2A and Sentinel-2B), it captures the exact same point on Earth every 5 days (and every 2–3 days at mid-latitudes), making it essential for breaking news cycles.
3. Vegetation Red Edge Analysis: Sentinel-2 includes three specialized red-edge bands (Bands 5, 6, 7) that can detect agricultural plant stress and soil churning days before it becomes visible in standard RGB photography.

Choose Landsat 9 For:

1. Thermal Surface Emissivity (TIRS-2): Sentinel-2 has zero thermal sensors. Landsat 9’s Thermal Infrared Sensor 2 (Bands 10 and 11) allows investigators to detect industrial thermal discharge into rivers, nuclear power plant cooling canal operations, and active geothermal/wildfire heat signatures.
2. Panchromatic Sharpening (15m): Landsat 9 includes a 15-meter grayscale panchromatic band (Band 8). In QGIS or ArcGIS, you can “pan-sharpen” Landsat’s 30-meter color bands with Band 8, yielding sharp 15-meter composite imagery.
3. Historical Baseline Comparison (50+ Years): Landsat 9 is cross-calibrated with the entire Landsat historical archive dating back to Landsat 1 in 1972, providing an unbroken half-century timeline for longitudinal environmental litigation.

3. Mathematical Formula Translation: NDVI, NDWI, and NBR

To run change-detection analysis across both satellite programs, use these exact formulas:

Normalized Difference Vegetation Index (NDVI)

Reveals vegetative health, crop yields, and tactical deforestation: - Sentinel-2: $\frac{\text{B08} - \text{B04}}{\text{B08} + \text{B04}}$ - Landsat 9: $\frac{\text{B05} - \text{B04}}{\text{B05} + \text{B04}}$

Normalized Difference Water Index (NDWI)

Maps open water reservoirs, flood inundation zones, and wetland drainage: - Sentinel-2: $\frac{\text{B03} - \text{B08}}{\text{B03} + \text{B08}}$ - Landsat 9: $\frac{\text{B03} - \text{B05}}{\text{B03} + \text{B05}}$

Normalized Burn Ratio (NBR)

Measures the severity of wildfire burn scars and artillery bomb strike clusters: - Sentinel-2: $\frac{\text{B08} - \text{B12}}{\text{B08} + \text{B12}}$ - Landsat 9: $\frac{\text{B05} - \text{B07}}{\text{B05} + \text{B07}}$

By pairing Sentinel-2’s rapid 5-day, 10-meter optical cadence with Landsat 9’s calibrated thermal infrared measurements, investigators achieve complete evidentiary surveillance across both spatial and thermal spectra.