Environmental Science lecture notes
Environmental science first lecture:
-water vapor is at the center of the atmosphere
-dark grey areas on water vapor scale means its relatively dry compared to lighter areas
-higher co2 ppm per million molecules in the atmosphere… rapid increase since industrial
atmospheric aerosols influence air temperature, play a role in cloud formation, are generated
by human activities and natural processes, include sea salt crystals
We find Ozone at ground level cause of cars' fumes.. Found in smog. It is bad on the ground.
1. The thermosphere has extremely high temperature, but a person exposed to it would
rapidly freeze. Explain this apparent contradiction.
-not enough molecules close to each other to transmit the heat to your body plus the
pressure is so low.
2. What climate-change processes might you expect to witness during your time? Which ones
do you think take too long for you to experience?
-Seasons. Global warming/ice age
Environmental Science lecture 2
-air is denser near the Earth's surface
atmospheric pressure is force exerted by air molecules per unit area
Ideal Gas Law states:
--> slide 3
temperature=constant X pressure
-air pressure decreases with altitude -air at a higher altitude less dense -> less oxygen
-altitudes above 3000 meters can cause mountain sickness
Pressurized cans of shaving cream say not to expose to excessive heat. What might happen if
it is and will this potential problem last throughout the product life.
A standard pressure of 1,013.2 hPa is also known as one atmosphere (1 ATM). Look at the
next figure and determine at approximately what levels you would record a pressure of 0.5
ATM and 0.1 ATM.
Lecture slides 4:
Solar luminosity was much less 4.6 billion years ago when Earth formed. The Earth was colder
To find the intensity of the radiation:
Stefan-Boltzman equation: E=oT^4
A blackbody is a body that is perfectly efficient at emitting radiation
For graybodies, Stefan-Boltzmann equation becomes I=eoT^4
Wein's Law: A=2897/T
The impact on Earth's temperature if scattering in the atmosphere increase would depend on
which type of scattering. But usually colder.
If cloud cover increased, the Earth's temperature would be
Net Radiation= incoming radiation-outgoing radiation Poleward heat transport:
Surplus energy moves toward poles (deficit regions)
Poleward heat transport is a driving force of climate
Warming is occurring due to the presence of greenhouse gases. Incoming solar energy is
equaled to the outgoing IR energy. Greenhouse effect keeps the Earth warm. Without it the
Earth's temperature would be ~ -15 degrees celsius
Energy absorbed by Earth - Energy absorbed at the surface = Energy recycled within the
Would you expect both the Northern and Southern hemisphere to have same average
albedo/ What factors might cause the two hemispheres to reflect different percentages of
insolation back to space?
-->No they won't have the same average altitude because southern him sphere has more
water than land mass, and northern hemisphere has more land so more snow will increase
Which would have the greatest effect on the Earth's greenhouse effect:
Removing all of the CO2 from the atmosphere or removing all of the water vapour? Explain
why you chose your answer.
Environmental Science Lecture 3
Sub-solar point - at noon, the sun will be directly over it -summer in the southern hemisphere is associated with the sub solar point at 23.5 degrees
-an average rate of 55W/m^2 in insolation can be observed at 90 degrees South, at the
-an average rate of 440W/m^2 in insolation can be observed at 0 Degrees, at the March
-the maximum temperature occurs in mid-late afternoon even though the the amount of time
it takes to reradiate the solar radiation
-temperature is more inconsistent the further from the equator
-equatorial zone is associated with rain forests
-grasslands are associated with the midlatitude zone
-If the Earth was not tilted, the Earth's radiation budget would have a greater loss of energy
at high latitudes
-coastal locations have lower temperature ranges than locations inland because it takes a lot
more energy to heat up a body of water than land -wind mixes the warm water with the cold
water -greater loss of latent heat with a body of water
Continentality-effect of an inland location that favours greater temperature extremes
-What factors influence local temperatures--> surface type, latitude, elevation
-The surface type contributes the most to maintaining temperatures at a given location
higher than nearby areas (asphalt holds heat more than vegetation, farmers fields etc.)
-there will be a higher range of temperature year round the further the area is from water/the
higher the latitude
-the Wind-Chill index is the "feel" of temperature under cold conditions QUESTIONS:
An orchard farmers hears a weather forecast for overnight low temperatures to hover just
above freezing point of 0 Degress Celsius, but with wind chill temperatures expected to drop
Will the wind chill increase the possibility of frost damage? Why or why not?
Suppose that the Earth's axis were tilted at 40 degrees to the plane of the ecliptic, instead of
How would the seasons change in Hamilton? what would be the global effect of the change?
ANSWER: The summer would be hotter, winter would be colder. The seasons would be even
-Humidity is the amount of water vapour in the air.
-Specific Humidity (SH) is the actual quantity of water vapour in air
-SH=mass of water vapour (g)/mass of total air (kg)
-Saturation Specific Humidity is the maximum amount of H2Ov (i.e. SH) that an air parcel can
contain at any given time based on its temperature
-Saturation is achieved when the density of gas cannot be increased above a certain level -
change of phase once limit is reached
-Dew Point - Temperature at which air, when cooled, becomes saturated
-If two air parcels have the same specific humidity, but different temperatures, they will still
have the same dew point
-Relative Humidity (RH) = 100 X (SH/saturation SH) -If there temperature rises, and the specific humidity stays the same, the relative humidity will
How can frozen clothes "dry" outside in subfreezing weather? What is taking place?
A crowded classroom is filled with students. In what way the presence of the students affect
the dew point and relative humidity in the room?
2. Dew point will be increasing because of more moisture and the more people makes it
hotter too. The relative humidity decreases. If the increase in the temperature is far larger
than the increase in the dew point, the relative humidity will decrease.
Environmental Science Lecture 4
-Pressure (mb) is the same as hPa
-Rate of temperature decrease with altitude for a parcel of dry or unsaturated air as it rises:
10 degrees celsius/1,000m
-rate of temperature decrease with altitude for a parcel of air saturated with water vapour as
it rises: 4-9 Celsius/1,000m
-lifting condensation level (LCL): height at which saturation occurs
Diagram from bottom to top
-Air cools at DALR - Unsaturated
-Air becomes saturated - saturated
-Air cools at SALR - SALR=MALR
-Level of free convection LFC
Latent heat released compensates for decrease in temperature Atmospheric stability - no vertical movement occurs
-Stability: Air parcel resists upward displacement
-Instability: air parcel keeps rising
Absolutely stable atmosphere is
ELR Spring and Summer, mostly summer (most thunderstorms in summer)
Is the stability of the air more likely to change rapidly near the surface or aloft? At what time
of day are major changes in the ELR most likely?
The ELR increases above 10km because the troposphere has been reached
Cumulonimbus cloud would be expected to see associated to convection under highly
unstable conditions (large difference between MALR and ELR)
Orographic uplift is when a cloud hits a mountain and has to rise up and cools down
The height of where the base of clouds forms is called the lifting condensation level
The air mass starts to warm as it descends the lee side of the mountain at the DALR Questions:
Why are advection fogs rare over tropical water?
--> it is not the best temperature for advection fogs to form
In many regions, the orographic effect causes precipitation to increase with elevation. Can
you think of any reason why this might not be true all the way up to the top of Mt Everest?
-->By the time the water vapour has been forced to lift along the mountain slope, it has
already condensed and formed into clouds and precipitation
Environmental science lecture 5
Lecture slide 9
-Precipitation is any form of water that falls from a cloud and reaches the ground
- In warm clouds (>0 Celsius): water droplets condense
- Constant speed achieved when air resistance = gravity: terminal velocity
- In cold clouds (<0 Celsius): ice crystals form & grow
-types of precipitation; rain, freezing rain (glaze), snow, sleet
-raindrops are not tear- shaped
-Bigger than 2mm then its a flattened sphere
-smaller than 2mm then its a sphere
Snow is distributed throughout North America
West: snowfall at higher elevations
East: lower temperatures favour snow over rain
-Lake effect snow is a strong enhancement of snowfall
Why is a warm, tropical cumulus cloud more likely to produce precipitation than a cold,
stratus cloud? -->there is more moisture that can be held with the cold stratus cloud
Both the arctic and the Canadian Prairies have relatively low snow cover. Is the cause for this
the same in both regions?
Lecture slides 10
-Water in all its forms: ~1.4 billion km^3
-Overland and interflow are affected by human development
-a water balance represents Hydrological cycle at the local scale
Water balance equation:
P= (PE-D) + S + or - AST
D= PE - AE
PE= potential evapotranspiration
AST: soil moisture storage change
AE= actual evapotranspiration
-if all demand is satisfied, AE=PE
-Deficit occurs when PE cannot be satisfied through;
P, soil moisture
Under ideal conditions; AE and PE are close
-Surplus: When PE is satisfied, and ST is full ACCWL: accumulated potential water loss
-water taken from ST when: P< or equal to PE
-october to mid december; recharge
1. What effect does a large ST have on a location as compared with another location that has
the same P and PE totals but a lower ST?
2. How do impervious surfaces such as parking lots impact the water balance terms?
--> the actual evaporation is going to be lower, and higher deficits in the summer months;
^ON FINAL EXAM
Environmental Science lecture 6
Lecture slides 11
-Wind is air that is moving horizontally relative to Earth's surface. It is caused by unequal
heating of the Earth's atmosphere
-Winds are generated by differences in pressure drive wide.
-Pressure gradient force: difference in pressure between regions
-Pressure is mapped by constant height: plot variations in air pressure on a constant elevatio