That’s the point I was trying to make. I don’t understand Bad Meteorology’s condemnation of the term. Engineers have been using the psychrometric chart quite successfully for some time for design purposes. The line at the top of the chart (the 100% relative humidity line) is referred to as the saturation curve. If a single iota of additional water is introduced to a particular volume of mixed air at a particular dry bulb temperature at 100% relative humidity, water will condense out. Hence, no moisture can be added, and it is saturated. I think that the argument that the term saturation is used by incompetent authors is just playing with semantics.
Bad Meteorology also argues that
"some incompetent authors present it to their readers as a percentage of the air’s holding capacity. "
Check out the psychrometric chart located at
Pick any dry bulb temperature (measured along the axis along the bottom of the page. Travel upward along the constant drybulb temperature line until it hits the saturation curve (RH=100%). Then travel in a line straight to the axis on the right hand side of the curve to read the humidity ratio, which measures the moisture in mixed air (in pounds of moisture per pound of dry air). Now go back again to your dry bulb temperature line. Follow the line upward until you reach the RH=50% curve. Now follow the line to the right axis to read the new humidity ratio. Divide the humidity ratio at 50%RH by the humidity ratio at 100%, and PRESTO! You have a ratio of 50%. The relative humidity curves DO show that, at a given dry bulb temperature, the mixed air at that given relative humidity does contain that percentage of moisture in relation to what how much moisture the air mixture would contain at saturation.
Where does the incompetence come in?