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HMS: Hydrologic Micro Services

Meteorology - Humidity

PRISM Humidity

The Parameter-elevation Relationship on Independent Slopes Model (PRISM) is a combined dataset consisting of ground gauge station and RADAR products. The data is on a 4km grid resolution covering the contiguous United States. Data is available from 1981 to present.PRISM data are reported in GMT (UTC). PRISM provides daily average temperature and dew-point temperature data. Relative humidity is calculated using a version of the August-Roche-Magnus equation as follows ): RH = 100*(EXP((17.625*TD)/(243.04+TD))/EXP((17.625*T)/(243.04+T))) where, RH is % relative humidity, TD is dew-point temperature (celsius), and T is air temperature (celsius).

Temporal Aggregations

Possible options include 'daily' and 'monthly'. Aggregated humidity data are the averages over these time periods and provided in the aggregated timeseries (Rh as well as dew-point temperature). Monthly aggregations correspond to the calendar month, and require the entire month to be specified in the date time span.