OPAL Knowledge Hub
Learn & Grow
Scientific papers, spacecraft details, and practical tutorials designed to help you extract the maximum value from Copernicus satellite observations.
Satellite Constellations & Sensors
Sentinel-2C Orbit & MSI Specs
Understand how Sentinel-2 multispectral sensors work, including spectral bands, calibration baselines, and quality masks.
Read Paper →Red-Edge Transition
Why the narrow wavelengths between 705nm and 783nm are the most critical diagnostic indicators of nitrogen and crop stress.
Read Paper →SWIR Water Absorption
How shortwave infrared bands (1610nm and 2190nm) isolate canopy hydration from chlorophyll greenness.
Read Paper →Scene Shadow Geometry
Projecting cloud boundaries and utilizing terrain elevation models to isolate shadowing from crop stress.
Read Paper →AOT Retrieval in Drylands
Atmospheric correction overrides and adaptive aerosol models when dense green vegetation targets are absent.
Read Paper →Synthetic Aperture Radar (SAR) Physics
Soil Moisture Synergy
A technical analysis of our radar-optical synergy, leveraging Sentinel-1 backscatter and the Water Cloud Model (WCM).
Read Paper →SAR Polarimetry: VV vs. VH
Explaining vertically and horizontally polarized radar signals and how they isolate soil permittivity from canopy structure.
Read Paper →C-Band Canopy Penetration
Analyzing how C-band wavelengths (5.6 cm) interact with broadleaf crop clumping and vertical grass structures.
Read Paper →Radar Soil Roughness Effect
Solving the problem of specular vs. diffuse scattering caused by fresh tillage and ridges, using the Oh and Dubois models.
Read Paper →Incidence Angle Normalization
Removing orbital path geometry and local slope bias to stabilize timeseries soil moisture trends.
Read Paper →Governing Equations & Historical Physics
Penman-Monteith Equation
The history and physical thermodynamics of standard evapotranspiration calculations, from Penman's 1948 breakthrough to the FAO-56 reference standard.
Read Paper →The Water Cloud Model
Detailing Attema & Ulaby's 1978 paper, vegetation scattering models, and using Sentinel-2 to isolate soil backscatter under growing canopies.
Read Paper →Root-Zone Water Balance
The bookkeeping math of daily soil water depletion, tracking root expansion, drainage percolation, and Managed Allowable Depletion (MAD).
Read Paper →FAO Yield Response Model
Doorenbos & Kassam's 1979 FAO Paper 33, growth-stage specific sensitivity coefficients (Ky), and predicting economic penalties of crop stress.
Read Paper →Crop Water Stress Index
Thermodynamics of stomatal cooling, Ray Jackson's 1981 energy balance equations, and satellite thermal VPD baselines.
Read Paper →Agronomy & Hydrological Models
Topp's Equation & Permittivity
The mathematical mixing models linking soil dielectric permittivity to volumetric water content values.
Read Paper →Dynamic Crop Coefficient Scaling
Replacing static calendar-day irrigation targets by scaling the FAO-56 Kc factor using Leaf Area Index (LAI).
Read Paper →Logarithmic Wind Profile
Correcting wind forecast velocities measured at 10 meters height down to the 2-meter crop boundary layer.
Read Paper →Double-Crop Phenology
Tracking growing degree days and double-peak NDVI curves to monitor fields yielding two annual harvests.
Read Paper →SoilGrids Depth-Weighted Profiles
Interpolating sand, silt, and clay textures across multiple vertical root layers for water balance accuracy.
Read Paper →CWSI Thermal Science
Measuring plant transpiration cooling using temperature differences between the canopy and the surrounding atmosphere.
Read Paper →Compliance, Security & Service SLA
Science Behind OPAL
The peer-reviewed scientific biophysics models, radiometric calibrations, and sensor formulas driving the platform.
Read Methodology →Security & Data Residency
How we encrypt data, handle Google Firebase authorization, and isolate spatial field databases inside the EU.
Read Whitepaper →Service SLA & Data Latency
Sentinel overpass frequency schedules, cloud coverage masking thresholds, and system processing SLA metrics.
Read Disclosures →