Meteorological concepts I. Ambient Humidity

The air in the atmosphere is composed of a mixture of gases, mainly Oxygen (21%) and Nitrogen (78%), but also water vapour which together with carbon dioxide and other gases (1%) make up 100% of its composition. These would be the percentages for air under normal conditions, in contrast to the soil atmosphere which have different levels. Only water vapour can increase its concentration with respect to the others; this is the case of humid air which, being lighter, rises from the surface of the water masses to higher layers.

The environmental humidity  of our golf courses It depends on the amount of water vapour that this air can hold at any given time. Since the amount of water vapour that air can hold depends on its temperature and pressure (warm air holds more than cold air), it is during the summer months that the air can reach its highest levels of humidity, both in absolute terms and as specific humidity (the amount of water vapour in a given volume of dry air), even when the relative humidity is low.

On the other hand, relative humidity gives us an idea of how saturated the air is in water vapour.

The maximum values of absolute humidity that the air can have will therefore occur in summer, although in winter it will be very easy to reach saturation and situations of intense dew.

It is therefore easy to arrive at situations of thermal stress in this summer season, due to the effect of the ambient humidity. R.G. Stedman developed the wind chill parameter as a combined effect of heat and humidity:

Our tool POGO measures and collects various factors that help to study the real reasons for the problems that the field has or may have, including leaf temperature, so it takes into account the effect of environmental humidity in the field.

Having a weather station is the perfect tool to know both the environmental humidity and all the variables necessary for a proper management of the field.

• Davis self-aspirated weather station