RHSI
Reproductive Heat Stress Index
MeasuresAccumulated exposure above crop-specific heat thresholds (>32–35°C) during flowering & grain/seed fill — the window where heat sterilises florets and aborts kernels.
Why it mattersReproductive heat is the dominant driver of catastrophic yield collapse; calendar-day metrics miss it.
Customer useCore trigger variable for parametric sunflower/maize covers.
TNRI
Tropical-Night Respiration Index
MeasuresRun of warm nights (Tmin above threshold) that drive respiratory carbon loss and prevent overnight recovery during grain fill.
Why it mattersNight heat erodes yield & grain weight even when daytime maxima look benign — invisible to daytime-only triggers.
Customer useBasis-risk reducer; explains losses daytime indices leave unpriced.
VPDI
Vapour-Pressure-Deficit Index
MeasuresAtmospheric drought stress — the evaporative demand the canopy faces — combining temperature and humidity, with soil-moisture context.
Why it mattersSeparates “hot but humid” from “hot and desiccating”; high VPD compounds heat damage.
Customer useDistinguishes heat-only from combined heat×drought events for cover design.
HQDI
Heat-Quality Downgrade Index
MeasuresHeat exposure timed to quality-critical windows — oil content in sunflower, protein/test-weight in cereals, kernel integrity in maize.
Why it mattersHeat hits grade and price, not just tonnage; processors are exposed to quality, not yield.
Customer useQuality-downgrade cover & procurement margin protection.
OHDI
Onset / Heat-Duration Index
MeasuresTiming, length and intensity of heatwave spells relative to phenology — early-onset vs prolonged vs compound events.
Why it mattersA 3-day spike and a 14-day plateau price very differently; duration & onset shape the loss curve.
Customer useTrigger shape & payout-curve calibration; portfolio accumulation.