Geographical Controls of Weather and Climate

Latitude

Continentality

Altitude

Topography

Terrain dimensions

Relief

Slope and aspect

Latitude

Net radiation and temperature decrease as latitude increases

Elevation of treeline/snowline decreases poleward

Belt of alpine vegetation and permanent snow and ice are lower on mountains at high latitude versus the tropics

Day Length

Continentality

Arises from differences in heat capacity and heat conduction of soils vs. water

Water able to store more heat

Soils less

Degree of continentality expressed by annual range of mean monthly temperature

Temperature: Annual vs. Diurnal

Austria

Altitude

Distribution of state variables (p,r,T,u) depends strongly on height in free atmosphere and as function of terrain height

Vapor pressure of water and radiation also vary strongly with height

Hydrostatic Atmosphere

dp/dz = - rg

p= rRT

ln(p_B/p_T )=RgT_ave (z_T – z_B )

Standard Atmosphere

Actual vs. Standard Atmosphere

Vapor Pressure

Vapor pressure (e)- partial pressure of water vapor

Absolute measure of water content in atmosphere

Saturation vapor pressure (e_s)- saturation vapor pressure

Maximum amount of water vapor atmosphere can hold for given temperature

Impacts of Vapor Pressure

Higher vapor pressure reduces transmission of IR

Refracts/absorbs solar radiation

Flux of water vapor proportional to (e_s –e); so, for given temperature, lower vapor pressure increases evaporation

Compared to free air, vapor pressure is higher usually near mountain

Reduces transmission of IR, which may increase temperature

Lowers condensation level

lowers drying power, i.e., ability to transfer water from clothing/plants into atmosphere

Physiological Factors of Altitude: Oxygen Deficiency

Proportion of Oxygen in atmosphere- 21%

Partial pressure of Oxygen decreases with height in proportion to other gases

Lungs saturated with water vapor; reduces available oxygen

Oxygen in lungs: (ambient pressure – saturation water vapor pressure at body temp (37C) (63 mb)) * .21

Sea level (1013 – 63 ) * .21 = 200 mb; 5000 m (540 – 63 ) * .21 = 100 mb

Hypoxia- intolerance to oxygen deficiency

Humans can tolerate half sea level value indefinitely

Symptoms significant above 3000 m (133 mb)

Standard Atmosphere varies with latitude (4000 m roughly 630 mb equatorward of 30^o; 593 mb (winter)-616 mb (summer) at 60^o

Cyclone could drop pressure 10-20 mb; equivalent to several hundred meters in elevation

Grover (1974); Man living at high altitudes. Arctic and Alpine Environments.

Inspired Oxygen as a Function of Elevation


	Latitude
	Continentality
	Altitude
	Topography
		Terrain dimensions
		Relief
		Slope and aspect


	Net radiation and temperature decrease as latitude increases
	Elevation of treeline/snowline decreases poleward
	Belt of alpine vegetation and permanent snow and ice are lower on mountains at high latitude versus the tropics


	Arises from differences in heat capacity and heat conduction of soils vs. water
		Water able to store more heat
		Soils less
	Degree of continentality expressed by annual range of mean monthly temperature


	Distribution of state variables (p,r,T,u) depends strongly on height in free atmosphere and as function of terrain height
	Vapor pressure of water and radiation also vary strongly with height


	Vapor pressure (e)- partial pressure of water vapor
		Absolute measure of water content in atmosphere
	Saturation vapor pressure (e_s)- saturation vapor pressure
		Maximum amount of water vapor atmosphere can hold for given temperature


	Higher vapor pressure reduces transmission of IR
	Refracts/absorbs solar radiation
	Flux of water vapor proportional to (e_s –e); so, for given temperature, lower vapor pressure increases evaporation
	Compared to free air, vapor pressure is higher usually near mountain
		Reduces transmission of IR, which may increase temperature
		Lowers condensation level
		lowers drying power, i.e., ability to transfer water from clothing/plants into atmosphere


	Proportion of Oxygen in atmosphere- 21%
	Partial pressure of Oxygen decreases with height in proportion to other gases
	Lungs saturated with water vapor; reduces available oxygen
	Oxygen in lungs: (ambient pressure – saturation water vapor pressure at body temp (37C) (63 mb)) * .21
	Sea level (1013 – 63 ) * .21 = 200 mb; 5000 m (540 – 63 ) * .21 = 100 mb
	Hypoxia- intolerance to oxygen deficiency
		Humans can tolerate half sea level value indefinitely
		Symptoms significant above 3000 m (133 mb)
	Standard Atmosphere varies with latitude (4000 m roughly 630 mb equatorward of 30^o; 593 mb (winter)-616 mb (summer) at 60^o
	Cyclone could drop pressure 10-20 mb; equivalent to several hundred meters in elevation
	Grover (1974); Man living at high altitudes. Arctic and Alpine Environments.