Lesson 104 Flashcards
(14 cards)
According to ISA, what is the average MSL?
1) 29.92 Inches of mercury
2) 76 cm of mercury
3) 1013.2 mb/hPa
Define: Lapse rate Isothermal layer Positive lapse rate Negative lapse rate Subsidence
LR: The rate of temperature change with height
IL: No change of temperature with height
PLR: A decrease of temperature with height
NLR: An increase of temperature with height
Subsidence: The downward motion of air
Describe the adiabatic process.
A change in temperature of air caused by expansion or compression. The theoretical assumption is made that no heat is transferred (in or out) between a parcel of rising or sinking air and the ambient (external) air surrounding the parcel.
What is the atmospheric lapse rate?
The ALR is the rate of temperature change with height as determined by a radiosonde ascent at any given time. It varies day to day.
Describe the adiabatic lapse rate.
The ALR is the rate of temperature change with height inside a parcel of air due to expansion or compression of the parcel. It has two fixed values. It is a calculated theoretical value.
What are the two types of inversions?
Nocturnal inversions (caused by radiation cooling) Frontal inversions (warm air forced over cooler air, i.e. warm front)
What are the five types of lifting processes?
Convection Mechanical Turbulence Orographic lift Frontal lift Convergence
Mechanical turbulence is the result of ________ produced from the interaction between the surface of the earth and the air.
What are the 3 factors that influence the intensity of mechanical turbulence?
… Friction …
Unevenness of the ground
Speed of the wind
Stability of the air (instability increases the intensity)
The effects of mechanical turbulence are usually limited to the lowest ________feet of the atmosphere. This is also known as the ________ _________.
3000 feet
Boundary layer
Define Stability
The atmospheric resistance to vertical motion
As long as the atmospheric lapse rate is _______ than the dry adiabatic lapse rate, vertical movement will be ________, and the air is ________ ________.
Greater
Prolonged
Absolutely unstable
If the lapse rate in a portion of the atmosphere is ________ _______ the saturated adiabatic lapse rate, vertical movement is _______, and the air is ________ ________.
Less than
Resisted
Absolutely stable
When the lapse rate is between 1.5 and 3 degrees C, the air is stable unless lifted until saturation, or _______ _______.
Conditionally unstable
A lapse rate can be steepened by ________ _____ ________ or by _______ ____ _________ _______.
Heating from below
Decreasing temperature aloft
