Adiabatic Lapse Rates

What do you know about the Wet Adiabatic Lapse rate?

-       Less than dry adiabatic lapse rate

The more it slants = greater lapse rate 

Lapse rate = Rate of cooling

What’s the difference between the Dry and Wet Adiabatic Lapse Rate?

-   Unsaturated à reaches LCL à Saturated

-   Latent “Hidden” heat - The heat either released or absorbed as a result of a change of state.

-   When a cloud forms….

o   The water vapor reaches the LCL à Temperature decreases à It’s doing work à slows the rate of cooling

-   Water vapor condenses à latent heat is released

Mixing ratio (w) - A measurement of the amount of water vapor in the air of a given sized quantity of dry air. Grams of vapor per kilogram of dry air.

W = Water vapor in the box

-   Dewpoint Lapse Rate = As it goes up it decreases = 2 deg C / km

-   Dew point (Td) - The temperature to which air must cool at constant pressure in order for air to reach saturation (commonly dew to form); indicates moisture content.

Adiabats & Potential Temperature

Dry Adiabat = 333

·         Potential Temperature – A measure of heat. It is the temperature air would be if brought dry adiabatically to 1000 mb.

·         How much warmer will the potential temperature increase?

o   Has hidden heat, Lift up, pressure decreases, starts expanding, starts making hidden heat into real heat, which is determined by how much latent heat is left in the parcel

o   Wet adiabatic line will be parallel to the dry adiabatic line

§  Vapor starts condensing which makes latent heat turn into real heat

·         Latent heat becoming real is what is increasing the potential temperature -  delta = measure of real heat