1.Precipitation Flashcards
define hydrology
‘Hydrology is the science that treats the waters
of the earth, their occurrence, circulation, and
distribution, their chemical and physical
properties, and their reaction with their
environment, including their relation to living
things.’
During cretaceous: saskatoon was a ….
shallow inland sea
Saskatoon is in what river basin
South Saskatchewan River Basin
Describe a Hydrological schematic:
each rectangle is a storage compartment, arrows in between are called fluxes, circular rectangles are outputs
How much of the worlds water in the world is in the ocean ..%
(96.5%) and its saline
__% of fresh water is locked up in icecaps and sheets
70%
__% of fresh water is groundwater
30%
__% of fresh water is in surface, soil, and atmos
1.5
__% of the total water in the world is fresh
2.5
residence time/Water storage in different compartments takes differing ammounts of time dependent on where it is stored
Name Longest and Shortest
Longest:Groundwater-up to 4000 days
Shortest:
- Atmosphere-max 10 days
- Biological water 7 days
Measures of Water Vapour in the air(4)
- • Vapour pressure
- Absolute humidity
- Specific humidity
- Relative humidity
Vapour Pressure
– millibar (mb)
– Partial pressure contributed by water in atmosphere
-pressure from gases, mostly nitrogen, then oxygen(20%)
-each gas exerts a partial pressure contributing to total air pressure
-by looking at partial pressure of water vapour we get vapour pressure
Saskatoon Vapour pressure is about ___ mb
1000
Absolute Humidity
– g of water vapour per m3 of air
– Advantage
• Gives total amount of water present in air mass
• Useful for estimating possible precipitation
– Disadvantage
• Air expands as it rises
• Absolute humidity changes
– Even though all water vapour is still present
Absolute Humidity
– g of water vapour per m3 of air
– Advantage
• Gives total amount of water present in air mass
• Useful for estimating possible precipitation
– Disadvantage
• Air expands as it rises
• Absolute humidity changes
– Even though all water vapour is still present
- If air expand THEN HUMIDITY DECREASES AT IT IS SPREAD OUT OVER A GREATER SURFACE
Specific Humidity
g of water vapour per kg of air
– Advantage
•Does not change when air changes volume
Relative Humidity
– % – Percentage of maximum amount of water vapour the air can hold at certain temperature – RH = (ea / esat) * 100 %
To change relative humidity
• Changing amount of water vapour – Evaporation – Condensation . evaporation (humidifier) . condensation (dehumidifier) -HEATING AIR: RELATIVE HUMIDITY DECREASES -COOLING AIR: RELATIVE HUMIDITY INCREASES -cool to dewpoint At dewpoint: where condensation starts
• Changing temperature – Heating Relative humidity decreases – Cooling Relative humidity increases – Cool to dewpoint: RH = 100 %
Figure 2.1
Figure 2.1: Curve goes up to the right because hot air can HOLD more water
. Curve line is saturation line
.at the curve line is where that amount of air holds its maximum watercontent
Dew Point
how far the temperature has to go down to hit saturation
RH=
Saturation vapour pressure=1.5
Actual vapour pressure=4.25
(1.5/4.25)*100
33%
Why does ice have a different Evaporation vapour pressure?
.Over ice is lower saturated water pressure in comparison to over water
-ice releases less to evaporation then liquid water
Mechanism of Uplift(3)
. Mechanism of Uplift
- Cause precipitation by increasing humidity using uplift
1. Orographic
2. Convectional (Thunderstorm) - Figure 2.3: hot air rising surrounded by cold air like a hot air balloon
3. Cyclonic (Low pressure involved)
Atmospheric Air Pressure from North Pole to South Pole
- Polar High
- Subpolar lows
- Subtropical high
- Equitorial Low
- Subtropical High
- Subpolar Low
- Polar High
.equator heating causes rising motion while drawing in air from the north and south at the surface
-as air hits top of troposhphere it flows into northern and southern Hadley cells
-Subtropical high pressure belts develop from hot air coming from the equator which drive trade winds
Northeast Trades: because of rotation of the earth it rotates towards the southwest
SouthEast tradewinds: rotates towards Northwest
-These two create an equatorial trough(Low pressure system)
Poles: Cool down the atmosphere
-Polar High(cold air) flows out in the form of the polar Easterlies
-Boundary of westerlies and easterlies is POLAR FRONT(low pressure area)
Doldrums: Where Southeast and Northeast stop at the equator and little wind is present
Wind Paterns North Pole to South Pole
- Polar Outbreak/Front Easterlies
- Westerlies(Moving NE)
- Northeast Trade Winds(moving SW)
- Doldrum
- Southeast trades(moving NW)
- Westerlies(moving SE)
- Polar Easterlies(moving W)
global atmospheric circulation pattern from North Pole to South Pole
1.Polar Cell
2.Ferell Cell
3.Hadley Cell
Equator
4.Hadley Cell
5.Ferell Cell
6.Polar Cell
Environmental LapseRate:__degrees per 1000m
12
Rain Shadow
Adiabatic Cooling moving up the mountains causing warm/dry air coming over the leeward side in the form of a rain shadow
Siberian High
In January, it is over eastern Asia with arrows moving towards icelandic low
-does not appear in july
Aleutian Low
off the coast of Japan in January
-does not appear in july
Hawaiian High
off coast of California in January and moves a bit farther north in July
Azores High
remains on the coast of florida
-in january does not send arrows to canada
Figure 6.21
This is how a thunderstorm is formed
-On summer day, an air bubble which is hotter then surroundings rises and cools as it rises but it remains slightly warmer then surrounding air
-higher it goes, the bigger the difference in temp between air bubble and surroundings
-Environmental Lapse Rate(12 degrees/1000 meters) versus Wet adiabatic lapse rate(10 degrees/1000 meters)
-Environmental lapse rate can change dependent on day whereas Wet Adiabatic does not
.Lifting Condensation Level: is the altitude at which dew point occurs, and dew point is where relative humidity becomes 100%
Wet adiabatic lapse rate(__ degrees/1000 meters)
10
T OR F
Environmental lapse rate can change dependent on day whereas Wet Adiabatic does not
T
Lifting Condensation Level
.Lifting Condensation Level: is the altitude at which dew point occurs, and dew point is where relative humidity becomes 100%