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:
“I prefer “you” in the plural, I want “you,”
You must come to me, all golden and pale
Like the dew and the air.
And then I start getting this feeling of exaltation.”
—John Ashbery (b. 1927)
“Most childhood problems don’t result from “bad” parenting, but are the inevitable result of the growing that parents and children do together. The point isn’t to head off these problems or find ways around them, but rather to work through them together and in doing so to develop a relationship of mutual trust to rely on when the next problem comes along.”
—Fred Rogers (20th century)
“Someone is always at my elbow reminding me that I am the grand-daughter of slaves. It fails to register depression with me. Slavery is sixty years in the past. The operation was successful and the patient is doing well, thank you. The terrible struggle that made me an American out of a potential slave said “On the line!” The Reconstruction said “Go!” I am off to a flying start and I must not halt in the stretch to look behind and weep.”
—Zora Neale Hurston (1891–1960)