The dew point depression (T-Td) is the difference between the temperature and dew point temperature at a certain height in the atmosphere.
The smaller the difference, the more moisture there is, and the higher the relative humidity. In the lower troposphere, more moisture (small dew point depression) results in lower cloud bases and is also important to severe thunderstorms. Conversely, instability is increased when there is a mid-level dry layer (large dew point depression) known as a "dry punch", which is favorable for convection if the lower layer is buoyant.
As it measures moisture content in the atmosphere, the dew point depression is also an important indicator in agricultural and forest meteorology, particularly in predicting wildfires.
Famous quotes containing the words dew, point and/or depression:
“Keep up your bright swords, for the dew will rust them.”
—William Shakespeare (1564–1616)
“Zhivago: It seems you bombed the wrong village.
Strelnikov: They always say that. And what does it matter? A village betrays us, a village is burned. The point made.
Zhivago: Your point. Their village.”
—Robert Bolt (1924–1995)
“Mental health data from the 1950’s on middle-aged women showed them to be a particularly distressed group, vulnerable to depression and feelings of uselessness. This isn’t surprising. If society tells you that your main role is to be attractive to men and you are getting crow’s feet, and to be a mother to children and yours are leaving home, no wonder you are distressed.”
—Grace Baruch (20th century)