Module 2 Flashcards
Ideal gas concept
Theoretical concept allowing us to understand and create gas laws
Assumes gaseous volume is perfectly compressible, homogenous (acts the same regardless of composition),
There are no (or negligible) intermolecular forces between molecules in a gaseous volume
The majority of any gaseous volume is empty
Gas molecules are in constant motion in random straight lines
Molecules rigid spheres
Pressure within volume due to collisions between molecules and end inside of container
No loss of kinetic energy in collisions between molecules
These assumptions allow us to understand and predict atmospheric behaviours without measuring exact composition of every volume of gas
Boyles law
At a constant temperature the volume of gas varies inversely with pressure (larger volume less pressure)
Charles law
At constant pressure volume of gas varies directly with temperature. Temp rises volume rises.
Pressure conversion
14.7 psi = 29.92 hg = 1013.25 mb/hpa
Dalton’s law of partial pressure
As a heterogenous solution the atmosphere consists of multiple gases all of which contribute to pressure
Each gas occupies all available volume and the sum of the partial pressures create total pressure
(78% nitrogen 21% oxygen)
Atmospheric density equation
0.3484x (P/T)
T in Kelvin’s (c + 273.15)
P hPa
Pressure lapse rate equation
96T/ρ
T in Kelvin’s +273.15
ρ in hPa
Death zone
Above 8km over msl
Even with supplemental oxygen bodily function are messed up
Armstrong limit
18-19km over msl
Death in 60-90 seconds blood would start to boil
Net inflow vs net outflow
Net inflow: upper level divergence greater than surface convergence creating low pressure
Net outflow: upper level convergence greater than surface divergence creating high pressure
Speed, directional, mass convergence/divergence, and confluence
Speed convergence: air enters region faster than it leaves
Speed divergence: air leaves region faster than it enters
Directional convergence/divergence: air moves toward or away from a given point
Mass div/con: speed and directional occur simultaneously
Confluence: opposing patterns of speed and directional ie speed con direction div
Met conditions in high vs low p systems
Low: net outflow of air, surface con/upper div, unstable air, cumulus, rain, all air spins cyclonically from surface to upper troposphere
High: net inflow, surface Div upper con, mass subsidence, poor visibility, low level layer cloud, all air spins anti cyclonically from upper troposphere to surface
Convergence vs divergence
Convergence:
Slow moving cyclonically turning air
If at surface air is ascending
If aloft air is subsiding
Divergence:
Fast moving anti cyclonic air
If at surface air is subsiding
If aloft air is ascending
Causes and effects of subsidence
Causes
1 convergence just below tropopause air must go down
2 outward flow from a surface anticyclone causing divergence and sinking at the surface
3 downslope winds on the Lee side of mountains
4 cooling aloft
Effects
1 descending air experiences increasing pressure
2 air is warmed adiabatically
3 cloud within descending air evaporates
Therefore anticyclones usually present few to no clouds
Causes and effects of ascending air
Causes
1 orographic lifting
2 frontal surfaces
3 surfaces convergence (low pressure cyclones)
4 convection
5 low level turbulent mixing (causes ascent and descent)
Effects
1 stable air creates stratiform cloud
2 unstable air creates cumulus cloud
3 high moisture air creates low level stratiform with constant rain
4 low moisture cloud creates higher level possible tcu cb
