ENVS 224
how do you calculate % increase?
(new concentration - old concentration) / old concentration x100% ex: how fast did the concentration of Xgas increase from 0 to 2005? year 0: 278 ppm year 2005: 382 ppm make sure these two values are the same (ppm not ppb) BEFORE doing the calculations (382ppm - 278ppm)/278ppm x 100% = 37.4%
ozone layer
- not created by CO2 - created by CFCs - CFCs break balance of ozone equilibrium - UV rays break it into Cl- which interacts with oxygen atoms removing it from being able to react with O2 to recreate O3 depleting the amount of O3 - protects the biosphere by absorbing UV radiation - hole over Antarctica because.... - current status: starting to mend after we stopped putting CFCs into atmosphere - ozone hole doesn't contribute to climate change - thinner ozone layer actually has a COOLING effect cuz this would make the stratosphere cooler cuz the ozone layer makes it warmer - proves sun isn't driving climate change
troposphere
0-10km air temp DECREASES with INCREASING ALTITUDE troposphere is heated primarily by the Earths surface - heated from the bottom the "weather layer" - cuz majority of water vapor is found in this layer
UV radiation wavelengths
0.1-0.4 µm
visible light wavelengths
0.4-0.8 µm type emitted by the Sun
near - IR radiation wavelength emitted by the sun
0.8-4 µm
ppm to ppb
1 ppm = 1000 ppb 0.1 ppm (1000 ppb/1 ppm) = 100 ppb 385 ppb (1 ppm/1000 ppb) = .385 ppm
aerosol
1. VERY important to cloud formation and affect 2. fine solid or liquid particles 3. serve as the cloud contestation nuclei (CCN) - 1000x harder for clouds to form if no aerosols 4. they have direct and indirect effect on Earths climate affecting Earths radiation budget thought to be a "net cooling" effect 5. do effect climate change
3 factors that are used to asses a GHGs impact on global warming
1. abundance - know that CO2 is most abundant GHG that affects climate change then CH4 then NO2 2. lifetime - or residence time (will be given in table) 3. RF efficiency (will be given in table)
how does air reach saturation - 2 ways which is more typical (how does air reach saturation for cloud formation) (how do increase RH)
1. add water vapor 2. decrease air temp - more typical
carbon dioxide
1. long lifetime - remains in atmosphere for 30-1000 yrs 2. 2nd most abundant GHG 3. most responsible for climate change - largest contributor to human enhanced GHE 4. increased due to human activities from 280 ppm in the preindustrial era to 410 ppm today - 40 % increase
why is water vapor an important gas for weather
1. provides moisture source needed for weather formation 2. releases latent heat during condensation that supports storm development
water vapor
1. provides moisture source needed for weather formation 2. releases latent heat during condensation that supports storm development 3. most abundant GHG & contributes a lot to the greenhouse effect 4. does NOT drive climate change - stays in the atmosphere for too short of a time period (hours) and therefore cannot drive major changes affecting climate change
cloud formation
1. triggering process that lifts the air - convection - convergence - frontal lifting - orographic lifting 2. air rises 3. air expands and cools adiabatically 4. condensation occurs (clouds form) - two ways out •precipitation •latent heat released 5. latent heat released (from the second way out of step 4) 6. air warmed 7. air becomes buoyant and unstable and returns to step 2 and process starts over again
stratosphere
10-50km contains the ozone layer air temp INCREASES with INCREASING ALTITUDE
If the air temperature at sea level (altitude=0 km) is 15 °C, what is the air temperature at the altitude of 2 kilometers? Show the process of your calculation. [Hint: The air temperature by average drops with increasing altitude at 6.5 °C per kilometer in the troposphere.]
15 - (2 x 6.5°C) = 2°C is the temperature at the altitude of 2 kilometers
what are the three most abundant GHGs
1: water vapor 2: carbon dioxide 3: methane
thermal IR radiation wavelength
4-50 µm type emitted by the Earth
The standard air pressure at sea level (altitude=0 km) is 1,013 hPa. The air pressure at 3 km altitude is 700 hPa. What percentage of the total atmospheric mass is located above 3 km altitude? What percentage of the mass is below 3 km altitude? Must show process.
700/1013 x 100% = 69.1% total atmospheric mass is located above 3 km altitude (1 - 700/1013) x 100% = 30.9% total atmospheric mass is located below 3 km altitude
RH ex problem: temp: 20°C AVC: 7g/kg look for SVC based on given temp: 14g/kg is this saturated or unsaturated
7g/kg/ 14g/kg x 100% = 50% unsaturated cuz less than 100% the 14g/kg SVC means: for every one kg of dry air you need at least 14g water vapor to reach saturation
given: air temp = 77°F ; RH = 40% find the actual vapor content from looking at the graph 77°F correlates to 20g/kg SVC
AVC = [RH(SVC)]/100 AVC = [40(20)]/100 = 8g/kg
given: air temp = 41°F ; RH = 90% find the actual vapor content SVC is 5 based on temp
AVC = [RH(SVC)]/100 AVC = [90(5)]/100 = 4.5g/kg
An air parcel (with a temperature T0 and relative humidity RH0) rises from the ground into the atmosphere, losing its water as rain and getting cooler following the moist lapse rate. After that, it sinks back to the ground without replacing the water. Is this air parcel now warmer or cooler than T0? Is its RH now higher or lower than RH0?
After the air sinks back to the ground without replacing the water the air parcel is now warmer than T0 and its RH is now lower than RH0.
air pressure increases or decreases with increasing altitude why?
Air pressure EXPONENTIALLY DECREASES with increasing altitude because air density drops exponentially with increasing altitude due to gravity and the mass/height in air column above also decreases
The figure below shows how the monthly average albedo values change at 25ºN, 45ºN, and 65ºN latitude. How does albedo generally change with season? Why does it change this way?
Albedo is generally highest in February and it is generally lowest in August. It changes this way because in the winter reflective surfaces increase, such as snow, and as the seasons change in August there is an increased amount of non-reflective surfaces, such as water and vegetation.
be able to read radiative forcing graph (the colorful ones)
BE SURE TO DETERMINE WHICH SIDE IS ACTUALLY THE RADIATIVE FORCING SIDE you determine it by subtracting the top of the individual color to the bottom of that color not to the bottom of that graph
when the concentrations of ch4 and co2 Both increase by 1 ppb which gas traps more heat?
CH4 would trap more heat
How does the cooling effect of clouds work? How does the warming effect of clouds work?
During the day clouds have a cooling effect by effectively reflecting the incoming sunlight. During the night clouds have a warming effect by efficiently absorbing Earth's outgoing IR and emit a portion of absorbed IR back to Earth and warm Earth's surface.
global warming vs global climate change
Global warming refers to the global average temperature increase. Climate change refers to the variability of the mean state of the climate persisting for an extended period of 30 years or more.
Compare high clouds and low clouds. Which have a net cooling effect? Which have a net warming effect?
High clouds, such as cirrus clouds, have a net warming effect because they emit less IR to space because of colder cloud tops and therefore trap more heat. Low clouds, such as stratus clouds, have a net cooling effect because they reflect more sunlight because they are optically thick.
peak Earth's radiation is in the UV, visible, or IR range?
IR
If all the ice cover in the world became darker, would the overall albedo value of the Earth increase or decrease? Would it have a cooling or warming effect on the climate system, if other conditions remained constant? Explain your answer.
If all the ice cover in the world became darker the overall albedo value of the Earth would DECREASE This would have a warming effect on the global climate because the icecaps would absorb more of the sunlight rather than reflect it which decreases the albedo and has a warming effect thus making the global climate warmer - it would enhance global warming.
greenhouse gases absorb which type of radiation
Infrared Radiation
most abundant gas in atmosphere
Nitrogen concentration: 78%
does RH give an accurate indication of the ACV in the air?
No RH can only show % saturation - it CANNOT determine AVC
Does a RH of 25% measured on a cold day in January indicate the same water vapor presence as a RH of 25% measured on a hot day in July? Which contains more actual water vapor content? Explain.
No, an RH of 25% on a cold day in January and an RH of 25% on a hot day in July do not indicate the same water vapor presence. An RH of 25% on a hot day in July would have more actual water vapor content.
second most abundant gas in the atmosphere
Oxygen concentration: 21%
calculating % mass of atmosphere above below altitude given the pressure at that point
P% above = (Px/Po) x 100% P% below = (1 - Px/Po) x 100% ex: the air pressure at 0 km altitude is 1000 hPa. the air pressure at 12 km altitude is 250 hPa. what percent is located BELOW 12 km? Px = 250 Po = 1000 (1 - Px/Po) x 100% = (1 - 250/1000) x 100% = 75% what percent is located ABOVE 12 km? (Px/Po) x 100% = 250/1000 x100% = 25%
if co2 doubles from preindustrial lvls (280 ppm) estimate the consequent radiative forcing
RF = 1.4x10^-5(560000ppb-280000ppb) = 3.92 W/m^2
estimating RF efficiency given graph - must determine concentrations of the gas from that ex concentrations of CO2 1750: 277ppm and 2015: 390ppm
RF = RF efficiency x increase in the concentration (RF efficiency found in the table this example is using CO2) MUST BE IN THE SAME UNITS - have to convert to ppb if ppm because the RF efficiency is in ppb RF = 1.4x10^-5(390000ppb-277000ppb) = 1.58 W/m^2
Describe how relative humidity (RH) changes on a typical 24-hour day. Explain why it changes this way.
Relative humidity is typically highest at night and is lowest at around 3 P.M. It changes this way because when air temperature rises there is an exponential increase in the saturation vapor content and when this happens the RH drops. Relative humidity and air temperature have negative correlation. So, when temperature is lowest, typically at night, RH will be at its highest and when the temperature is highest, typically in the afternoon around 3 P.M., RH will be at its lowest.
saturation vapor content relationship with temp
SVC increases exponentially with increasing temp
greenhouse effect
The greenhouse effect is where certain gases, including carbon dioxide, water vapor, etc., absorb most of the Earth's outgoing infrared radiation and reemits a portion of the absorbed radiation in IR downward warming Earth's surface. This keeps the planet warm, if not for the greenhouse effect the average temperature of the Earth's surface would be 59°F colder.
At what latitude do we observe the greatest seasonal variation? Explain why.
The latitude that has the greatest seasonal variation in albedo percentage is higher latitudes, in the figure below this is 65°N which is in the Arctic Circle. This is because of the seasonal change in snow and ice coverage during the winter months, which are very reflective surfaces, and the melting of those to create more water and vegetation coverage during the summer months and into fall, which are not reflective surfaces and therefore reduce the albedo effect. The change between the amount of reflective surfaces at this latitude are very extreme which translates to a extreme change in albedo percentage.
Refer to the three factors that determine a GHG's contribution to climate change and compare CO2 and CH4. Which factors tend to make CO2 a stronger GHG? Which factor tends to make CH4 stronger? Which gas (CO2 or CH4) overall contributes more to the GHE?
The three factors that determine a GHG's contribution to climate change are lifetime, abundance, and RF efficiency. 1. The atmospheric lifetime of CO2 is much larger than the lifetime of CH4, greater than 30 years - sometimes thousands - versus 12 years. 2. The concentration of CO2 in the atmosphere is also higher than the concentration of CH4. The RF efficiency of CO2 is very low, it is the least efficient GHG, CH4 is 26 times more efficient than CO2. The factors that makes CO2 a stronger GHG are its abundance and lifetime. The factor that makes CH4 a stronger is its RF efficiency. Overall, CO2 contributes more to the GHE because of its relatively high concentration and long residence time despite its low RF efficiency.
wiens displacement law
The wavelength of peak radiation is inversely proportional to the absolute (kelvin) temperature of the emitting object. (black body) The Sun is hotter its peak radiation is at Shorter wavelengths (or Visible) The Earth is cooler its peak radiation is at Longer wavelengths (or IR) Equation (given on equation sheet) (lamda)max = 2898/T (lamda)max is the wavelength of objects peak radiation in micrometers (µm) T is the absolute temp of the object
which law allows satellite instruments to 'measure' earths surface temp remotely from space
Wien's Law and Stefan-Boltzmann Law
A black body has a temperature of 98.6°F. [Note: Kelvin=(°F-32)/1.8+273.15.] Calculate the intensity of its radiation using the Stefan-Boltzmann Law THEN Calculate the wavelength of its maximum radiation using the Wien's Law. What type of radiation does it emit?
[(98.6F°-32)/1.8]+273.15 = 310.15K 5.67x10^-8Wm^-2K^-4(310.15K)^4 = 524.7 Wm^-2 (lamda)max = 2898µmK/310.15K = 9.32µm This emits infrared radiation, it is in the IR range (4-50µm).
planks law
all objects emit radiant energy at all times
humidity
amount of water VAPOR in the atmosphere
climate
an areas average weather condition over a long time GREATER THAN 30 YEARS and extremes and variations from the average weather conditions (avg temp and precipitation)
kirchhoffs law
an object (whose temp is not changing) that absorbs radiation well will also emit radiation well
orographic lifting as triggering process that lifts air
caused by mountain ranges as they force air up and it cools and forms clouds - cycle starts
The average temperature for the month of January in Chicago, IL is -3°C. is this weather, climate, or climate change?
climate
The summers here are warm and humid is this weather, climate, or climate change?
climate
The highest temperature ever recorded in Phoenixville, PA was 44°C on July 10, 1936. is this weather, climate, or climate change?
climate (due to word choice - 'highest...ever recorded')
convergence as triggering process that lifts air
converging winds making clouds as they collide - create uplifting
low albedo surfaces
dark colored and wet surfaces tend to be non-reflective water, forests, etc
why is water vapor not involved in climate change
does NOT drive climate change - stays in the atmosphere for too short of a time period (hours) and therefore cannot drive major changes affecting climate change
global warming
global avg temp increase
evaporation
heat is absorbed by water molecules and therefore is a cooling process to the atmosphere heat absorbs and cooling process
convection
heat transfer by mass movement or circulation of fluid or gas a medium is needed Warm air RISES and Cold air SINKS
radiation
heat transfer by the flow of electromagnetic waves no medium or contact needed
enhanced greenhouse effect
human activities have caused the concentrations of greenhouse gases in the atmosphere to increase too much greenhouse gases in the atmosphere will make earths surface temp increase caused by things like burning fossil fuels and deforestation
how does global warming affect the saturation vapor content?
if the air temp gets warmer then SVC will increase making cloud formation more difficult and will make precipitation less frequent this decreases chances of cloud formation less frequent regular precipitation events and more intense but infrequent precipitation events sidenote: oceans getting warmer means vapor incr but air temp incr -> exponentially more water vapor required but ocean only supplying linearly
when air rises rapidly.... in context of adiabatic temp change
it expands rapidly and cools adiabatically this cooling of the air makes the RH rise as there is a lot less vapor content needed to become saturated clouds are more likely to form
If all the ice cover in the polar regions would melt, would the overall albedo value of the Earth increase or decrease? Would it have a cooling or warming effect on the climate system, if other conditions remained constant? Explain your answer.
it would decrease the albedo affect - water is less reflective it would have a warming effect because water is less reflective and will absorb more sunlight which has a warring effect and would enhance global warming
condensation
latent heat is released by water molecules and therefore is a warming process to the atmosphere heat released and warming process
high albedo surfaces
light colored and dry surfaces tend to be reflective snow, ice, thick clouds etc
mixing ratio
mass of water vapor in a unit of air compared to the remaining mass of dry air = mass of water vapor (g) /mass of dry air (kg)
what is the correlation between RH and air temp
negative correlation
the temperature in Chicago at 4pm on Jan 6 2013 was 55°F, which was 25°F warmer than chicagos normal high for jan 6th is this evidence for climate change?
no example of weather not example of climate or climate change DOES NOT OCCUR OVER 30 YR PERIOD
do nitrogen and oxygen affect weather or climate
no neither of them do
adiabatic
no heat exchange
laws of radiation
planks law wiens displacement law stefan-boltzman law kirchhoffs law
air pressure
pressure exerted by the weight of the column of air above = air density x height of the column of air above x g
which heat transfer mechanism allows solar energy to reach Earths surface
radiation
relative humidity
ratio of the airs actual water vapor content compared with the amount of water vapor required for saturation at that temp and pressure RH = AVC(g/kg)/SVC(g/kg) x 100%
RH = 100%
saturated
the average surface temp of Mercury, Earth, and Mars are 430°C, 15°C, and -30°C, respectively the wavelength of which is the shortest? longest? rank them
shortest: Mercury cuz the hotter the body the shorter the wavelength longest: Mars cuz the cooler the body the longer the wavelength ranked shortest to longest: mercury, earth, mars
climate change
statistically significant variation in the mean state of the climate or in its variability persisting for a PERIOD OF 30 YEARS OR LONGER the change can be in the avg weather (avg temp and precipitation) or a change in the extreme weather conditions
which layer contains the ozone layer?
stratosphere
convection as triggering process that lifts air
sun heats up ground and ground level air and air then cycles as it goes through the process of rising-cooling-falling-and continuing
seven elements to describe weather
temp humidity wind (speed and direction) precipitation (amount and type) pressure clouds visibility (not important)
weather
the condition of the atmosphere at any particular time (could be in the past) and place
stefan-boltzman law
the intensity of an objects radiation is directly proportional to the fourth power of its absolute temp Equation (given on equation sheet) E = (sigma)T^4
absolute humidity
the mass of water vapor in a given volume of air = mass of water vapor (g) /volume of air (cubic meters)
albedo
the reflectivity of a substance, usually expressed as the percentage of radiation that is reflected from the surface.
RH > 100%
this doesn't occur for that long because condensation/precipitation will occur to lower it down to under or equal to 100% if below freezing will form frost if above freezing will form dew
radiation law math question given surface temp = 60 F determine the intensity of the solar radiation calculate wavelength of peak solar radiation
this example is for the Earth MUST CONVERT TO KELVIN FIRST!!!!!!! K = ((60-32)/1.8) + 273.15 = 288.7 K determine the intensity of the solar radiation (use stefan-boltzman law): E = 5.67x10^-8(288.7K)^4 THE TEMP MUST BE IN KELVIN = 3.9x10^2 W/m^2 calculate wavelength of peak solar radiation (use wiens displacement law): (lamda)max = 2898/288.7 THE TEMP MUST BE IN KELVIN = 10.04µm --> in IR range (4-50µm)
radiation law math question given surface temp = 5780 K determine the intensity of the solar radiation calculate wavelength of peak solar radiation
this example is for the sun determine the intensity of the solar radiation (use stefan-boltzman law): E = 5.67x10^-8(5780K)^4 THE TEMP MUST BE IN KELVIN = 6.3x10^7 W/m^2 calculate wavelength of peak solar radiation (use wiens displacement law): (lamda)max = 2898/5780 THE TEMP MUST BE IN KELVIN = 0.5µm --> in visible range (0.4-0.8µm)
which layer is the "weather layer" why
troposphere cuz: 1. the availability of water vapor (99.9% is found in the troposphere) 2. the unstable atmospheric condition that creates convective motion
what is the vertical structure of the atmosphere ie what is the order of layers from the Earth up
troposphere, stratosphere, mesosphere, then the thermosphere
ozone
two types: stratospheric O3 (10-50km) - "good" ozone, absorbs UV rays tropospheric O3 (0-10km) - "bad" ozone, air pollutant, GHG
RH < 100%
unsaturated
peak solar radiation is in the UV, visible, or IR range?
visible
Cumulus clouds presently cover the entire sky. is this weather, climate, or climate change?
weather
Snow is falling at the rate of 5 cm per hour. is this weather, climate, or climate change?
weather
the temperature in Chicago at 4pm on Jan 6 2013 was 55°F is this weather, climate, or climate change?
weather bad example of climate change
frontal lifting as triggering process that lifts air
weather front causes the formation of clouds as a warm front gets pushed up and then on top of a cold front and as air cools clouds are formed
