Precipitationh

Precipitationh is a term used in some meteorological and hydrological research to describe a humidity-adjusted precipitation index. It is intended to capture not only how much rain falls but also how atmospheric moisture conditions at the time of precipitation can influence the intensity and impacts of the event. Precipitationh is not a standard or widely adopted metric in official climate records.

Calculation and interpretation of precipitationh rely on combining precipitation rate with a humidity-based weight. A common formulation is H = ∫ I(t) × f(h(t)) dt over the duration of a precipitation event, where I(t) is the instantaneous rainfall rate (mm/hour), h(t) is the relative humidity (0–1), and f is a weighting function that increases with humidity (for example f(h) = h or a nonlinear function). This results in a dimensionless or unit-adjusted index that emphasizes periods when moist air coincides with rainfall. Different studies may choose different f(h) functions, affecting comparability.

Data sources and computation typically use time series from rain gauges, weather stations, or radar, combined with concurrent humidity measurements. Precipitationh is most useful for comparative assessments of rainfall impacts rather than for defining an absolute amount of precipitation. It can help in hydrological modeling, urban drainage planning, and risk screening by emphasizing events where high moisture content may amplify runoff or infiltration responses.

Limitations include the lack of standard definitions, sensitivity to the chosen humidity function, and potential redundancy with existing rainfall and atmospheric moisture metrics. As a research construct, precipitationh remains exploratory and is not part of standard meteorological practice.