The past informs. The future stays out.
We investigate backward-only lags and site-local calendars to prevent temporal leakage in evaluation.
LOCAL CALENDAR / BACKWARD-ONLYScience & support
HydroFlux: scope, support and how to read a result
Scientific honesty is part of the product. HydroFlux reports where the evidence is strong, where local verification is required and where it will not produce an estimate.
SCIENTIFIC ARCHITECTURE
Beyond a map. A model of the exchange.
The difference is how we connect observations, time and uncertainty.
One perspective is not enough.
We combine Sentinel-2 optical signals, Sentinel-1 radar and Landsat surface temperature with meteorological context.
OPTICAL + RADAR + THERMALAn estimate needs boundaries.
We evaluate conformal intervals and observed coverage by domain. A nominal 90% level does not guarantee coverage in every crop or region.
SPLIT-CONFORMAL / EVALUATIONDATA SOURCES / NO IMPLIED AFFILIATION
ESA Sentinel-1 / 2NASA / USGS LandsatERA5-LandFLUXNET / ONEFlux
Current HydroFlux engine
HydroFlux
A support-aware AI system for agricultural evapotranspiration, combining satellite observations, weather, terrain and field context with training evidence from eddy-covariance measurements.
- Spatial output
- 30 m ET grid
- Result contract
- ET or null · uncertainty · age · support
- Ground evidence
- Eddy-covariance training observations
01 — SUPPORT CONTRACT
Where HydroFlux is supported
Support is evaluated for every pixel and request. A crop name or country alone never guarantees support.
SUPPORTED
Strongest established domain
North American annual crops and forage when climate, land cover, sensor freshness and required context pass the support checks.
Typical examples: corn, soybean, wheat, forage and comparable annual cropping systems with usable observations.
LIMITED SUPPORT
Broader agricultural screening
Agricultural pixels outside the strongest evidence envelope, including specialty or perennial systems, may be returned with limited support and wider uncertainty.
Examples: vineyards, orchards, new climates, weak land-cover confidence or missing phenology and irrigation context. Verify locally.
ABSTAINED / OOD
No defensible estimate
HydroFlux returns null when critical evidence is stale, missing or contradictory, or when the pixel is outside the supported agricultural domain.
Examples: no usable optical and radar evidence, a clear observation older than 32 days, unresolved domain conflicts or non-agricultural surfaces.
SUPPORTED describes resemblance to the established evidence and input contract. It is not a claim of field-specific calibration or ground-truth certainty.
02 — SUPPORT-FIRST ROUTING
How a request becomes a supported result
The public contract is intentionally simple: inspect the evidence first, estimate only where support is defensible, and expose the reasons.
01
Inputs and domain assessment
The system evaluates sensor availability, crop and land cover, climate, terrain, irrigation, phenology and recent field history.
02
HYDROFLUX
30 mHydroFlux
Support-aware evapotranspiration engine
03
Conservative support decision
The system prefers a transparent null over unsupported extrapolation.
Strongest established domain
Estimate inside the strongest evidence envelope.
Broader agricultural screening
Estimate supplied with a clear verification warning.
No defensible estimate
No value supplied when evidence is insufficient.
04
Daily ET at 30 m — or null
Every pixel includes uncertainty, observation age, support status and human-readable reasons.
This diagram documents the product contract without exposing private implementation details. Support can vary within the same field.
03 — DAILY PRODUCT
How the daily product is derived
A daily map combines the latest valid multi-sensor HydroFlux anchor with daily weather and reference ET. It always declares how final the result is.
Latest valid HydroFlux anchor
Multi-sensor crop state over the 16-day observation window
Daily weather + FAO-56 ET0
Radiation, temperature, humidity, wind and rainfall
30 M GRID
Daily evapotranspiration map
Uncertainty · observation age · support status · temporal status
ForecastProvisionalReconciled
04 — INTERPRETATION01 02 03 04
How to read a result
Four fields decide how much weight a number deserves.
Support status
Whether the pixel sits inside the validated domain. Limited support is a signal to verify locally, not a defect to hide.
Uncertainty
An operational range that widens as evidence weakens. Treat it as a heuristic band, not as validated probabilistic coverage.
Observation age
Days since the last clear Sentinel-2 or Landsat observation for that pixel. Older evidence caps support and widens uncertainty.
Abstention
A pixel with no usable estimate returns null. An abstention is information, not a gap to fill with a candidate value.
05 — LIMITATIONS
Current limitations
- The strongest established support is for North American annual crops and forage. Broader agricultural coverage is not a universal validation claim.
- Uncertainty is an operational heuristic. It is not a validated probabilistic coverage interval.
- Historical ERA5-Land context is sampled at roughly 11 km at the field centroid. It is not an independent 30 m climate observation per cell.
- A clear observation older than 32 days forces abstention rather than extrapolation.
- HydroFlux can show a water estimate and its support status. Irrigation prescriptions stay outside it. Whether a difference should change an action is a separate decision. Water-response validation is still in progress.