PyroSync — Scientific Harmonization Methodology

2026 NASA Space Apps Challenge — Harmonization of MODIS and VIIRS Active-Fire Observations

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1. Four-Stage Harmonization Pipeline

VIIRS 375 m instruments (Suomi-NPP, NOAA-20, NOAA-21) detect roughly 4.8x more active-fire pixels than legacy MODIS 1 km (Terra, Aqua) because smaller sub-pixel fires are resolved. Direct raw-count stitching introduces an artificial step jump after 2012. PyroSync reconciles both constellations in four deterministic stages:

  1. Schema & Quality Standardization: Unifies MODIS (brightness, bright_t31, 0-100 confidence) and VIIRS (bright_ti4, bright_ti5, nominal/high/low confidence) with integer coordinate deduplication (1e-5 deg).
  2. Equal-Area Cosine Grid (A1 & A10): Projects every fire pixel onto latitude-adjusted equal-area cells (~1.23 km2 at A1, ~123 km2 at A10), collapsing multiple 375 m VIIRS pixels inside a single MODIS-scale cell per satellite overpass.
  3. MODIS-Equivalent Sensitivity Floor (6.2 MW): Evaluates each VIIRS overpass-cell against the empirical MODIS 10th-percentile FRP sensitivity floor (F = 6.2 MW), filtering isolated smoldering pixels invisible to MODIS while keeping dense sub-pixel clusters whose cell sum reaches 6.2 MW.
  4. Overpass Mean & Empirical Gain Calibration: Combines Terra, Aqua, SNPP, NOAA-20, and NOAA-21 passes by mean per cell-day (preventing constellation double-counting) and fits median cross-sensor FRP gain k with 1,000-bootstrap 95% confidence bounds over overlapping non-partial archive days.
numCols(row)  = max(1, round(360 * cos(lat_center) / res))
cellID        = row * 40000 + col
kept(VIIRS)   = sum(frp_mw per overpass-cell) >= 6.2 MW
robust_z(d)   = (H_d - median(H_{doy +/- 7})) / max(1.4826 * MAD, 0.05 * median, 1.0)

2. Space Agency Data Declaration

This project uses active fire data from NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE) Fire Information for Resource Management System (FIRMS), specifically MODIS Collection 6.1 (Terra/Aqua) and VIIRS 375 m Collection 2 (Suomi-NPP, NOAA-20, NOAA-21) standard processing and near real-time products.

Basemap cartography: Esri, HERE, Garmin, OpenStreetMap contributors, and the GIS user community (World Dark Gray Canvas tiles).

3. AI Tool Declaration

Architecture planning, code scaffolding, and documentation refinement were assisted by AI coding assistants. All scientific harmonization formulas, equal-area spatial aggregations, bootstrap confidence intervals, and validation metrics are deterministic and computed directly from official NASA FIRMS datasets in Go and PostgreSQL/PostGIS.