Energy Research Unit Meteorological Data

About the Humidity Probe

The Humidity probe  is mounted 3m above the ground on the ERU Control Room. It is an integral part of a combined Humidity/Temperature Probe.

Humidity is the amount of moisture in the air. It can be measured in various ways, but the most usual in meteorology is to measure 'relative' humidity. This measures the absolute humidity relative to the maximum absolute humidity for the current temperature and pressure, and is expressed as a percentage [%rh]. A relative humidity of 100rh% means the air is saturated with moisture. Air can hold less moisture at lower temperatures, so that as temperature falls the air can become saturated and condensation can occur.

Humidity is important in wind energy research as it affects the mass of air and therefore has a small but important effect on the power in the wind at a given wind speed.

We feel the effects of humidity and can tolerate dry heat much better than damp heat. When relative humidity is low, evaporation is rapid and we can lose heat by perspiration. On the other hand, when relative humidity is high, we cannot lose heat by perspiration and feel sticky, hot, and uncomfortable.

Our probe is supplied by Skye Instruments .