atoc 1060 exam 2
What hemisphere would you expect to have a larger annual temperature range (summer average -winter average ? )
North Hemisphere
Ocean Density
P= p⚬- aT + BS Variables- p- density @ specific location or depth T- temp S- salinity Constants- po- average density a-thermal expansion coefficient B-saline expansion coefficient
Hadley Circulation
a thermally direct circulation on each side of the equator. •Warm air rises, cold air sinks •The equator is warmer than the poles •Warm moist air at the equator rises upwards •This air rises, expands, cools and saturates •The air moves poleward at the tropopause •The air descends at about 30°N and 30°S •The air then blows along the surface back towards the equator
Lifted Condensation Level
(LCL) is formally defined as the height at which RH of an air parcel reaches 100% •As the PBL grows throughout the day, if it reaches the height of the LCL, clouds will form •Then rain will occur
Idealized Meridional Circulation
* see pic *
Anthropogenic Emission Sources
-Energy Supply •Coal fired power plants, oil, and natural gas--used by consumers for electricity and heating -Industry •Electricity and heating used by the industrial sector •Greenhouse gases released as a byproduct of cement production, chemical processing, and other industrial processes -Forestry •Carbon released from forest clearing and forest burning -Agriculture •Methane released by ruminants such as cows used as livestock •Cultivation of rice paddies which provide breeding grounds for methanogenic bacteria -Transport •Petroleum-based fuels used for personal and commercial transportation -Residential and Commercial Buildings •Construction and maintenance•Electricity requirements -Waste Management •Landfill methane
If all the global sea ice melt, what is the expected mean sea level rise
0 meter s "Any floating object displaces its own weight of fluid."-Archimedes
What country would you say emits the most GHGs annually
1)China -22.7% Global total
Which of the following statements are false
1)Climate change can't be real because it was 50°F in the middle of summer. 2)Climate change is apparent when seeing the increasing cost of the tornado damage. 3)Climate change's impact on hurricanes is hard to tell because we don't have observations from 1890. 4)All of the above. *5)Only a and b*
Observed Temperature Change
1884- colder than avg 2000-2015- warmer than avg
Isopycnals are lines of constant density. On this diagram, which isopycnalindicates the highest density
3 (lower right corner of graph) bc lowest temp and highest salinity
Carbon on land (equation)
6 CO2 + 6 H2O ~~light~~> C6H12O6 + 6O2 ( carbon dioxide and water = sugar and oxygen
LCL and PBL
6-hour precipitation graph On 3 days, convection is triggered. •PBL > LCL
Carbon on land
Carbon on land •Photosynthesis is the main land sink for carbon •Photosynthesis is the metabolizationof water and carbon dioxide to form carbohydrates and produces oxygen as a by-product •Provides energy and nutrients for vegetation Vegetation is primarily made of carbon •The Amazon contains 90-140 billion tons of carbon •Equivalent to ~100 years of emissions
The Southern Oscillation Index describes the relationship between pressure in Darwin, Australia and Tahiti.If Tahiti has higher pressure that Darwin, which of the following would you expect
Coastal upwelling along the eastern pacific SOI- - ^ upwelling - la nina conditions -pgf is east to west
Evaporative Fraction
Evaporative Fraction •Evaporative Fraction (EF) is a metric that many climate scientists use to determine how wet a region is Latent Heat ---------------------- Latent Heat + Sensible Heat •EF is bounded on the scale of 0 to 1 •EF of 0 can be associated to a desert •EF of 1 can be associated to rain forest
True or False, the cost of hurricane damage is good indicator of climate change's impact on hurricanes
False
Causes of precipitation
Frontal lifting (Cold front) •Cold air "wedges" itself under warm air, lifting warm, less-dense and moist air into the air and causing precipitation •Convection •Occurs when the Earth's surface becomes heated, the atmosphere becomes unstable , then air rises •Orographic lifting •Caused when an air mass is forced upward by wind driving the air upslope
Warming Tropics
Ideal Gas Law, PV = nRT •As T increases, V will increase •If tropics warm, Hadley Cell expands•Deserts move poleward •Tropical air will increase evaportation •Water vapor in atmosphere increases •Water vapor is GHG, amplifies greenhouse effect •More warming
temp and density salinity and density
Increasing temperature lowers density Increasing salinity increases density
Latitude
Lines of latitude display the north or south position .•Lines of latitude are always 111 km apa
Longitude
Longitude provides the east or west position •Lines of longitude are 111 km apart at the equator and 0 km apart a
Do Milankovitch Cycles explain recent temperature variations on Earth?
No
Sensible Heat Flux
Sensible heat flux is the transfer of heat through air movements. •The warmth felt as warm air rises •Directly proportional to the temperature difference between an object and the surrounding air •In non-scientific terms, spatial transfer of the "jiggly-ness" of molecules •As molecules heat up, they become more "jiggly
Intertropical Convergence Zone (ITCZ)
The ITCZ is a region near the equator where the trade winds converge •As horizontal winds converge, vertical motion must be the result. The ocean is horizontal barrier, so the air must move upward. •This upward motion is where the NH and SH Hadley cells meet
Which of the following best explains why the atmosphere transports heat toward the poles
The latitudinal imbalance of absorbed solar energy
Paleoclimate 2
The most recent North American glaciers reached their maximum thickness and extent about 18,000 years before present (yBP), and then glaciation ended abruptly about 12,000 yBP •Continental ice sheets appear to have developed over a period of 90,000 to 100,000 years •The interglacial periods between major glaciations were probably slightly warmer than at the present
Evaporation and Salinity
high evaporation - high salinity •Areas with high evaporation rates tend to have higher salinity •Evaporation removes water from the ocean, raising salt concentrations •The salt does not get evaporated
Precipitation and Salinity
low salinity - high precip •There is a strong correlation between areas where precipitation is high and salinity is low •Adding freshwater via precipitation dilutes the salinity
Why is there an oscillation in the increasing trend of carbon dioxide
photosynthesis
What do you expect would have the highest albedo
snow
Latent heat flux
solid -> liquid -> gas solid to gas- sublimation makes surrounding area cooler bc takes heat (endothermic) gas to solid - deposition makes surrounding area warmer bc releases heat (exothermic)
SOI equation
standardized tahiti - standardized darwin ------------------------------------------------ msd If Standardized Tahiti > Standardized Darwin •PGF is east to west •Increased upwelling •La Niña condition •If Standardized Tahiti < Standardized Darwin •PGF is west to east •Increased downwelling •Less upwelling •El Niño conditions
Intergovernmental Panel on Climate Change
the IPCC is a scientific andintergovernmental bodyunder the auspices of theUnited Nations Dedicated to the task of providing the world with an objective, scientific view of climate change and its political and economic impacts
The Planetary Boundary Layer
the layer of the Earth's atmosphere between the Earth's surface and the free atmosphere •Responds to changes in radiative forcings •Generally well-mixed due to turbulent m
A hurricane has a center of low-pressure and we know low-pressure systems are associated with convergence and rising motion, yet there is sinking air in the middle of the hurricane
true
Walker Circulation• The Walker Circulation can weaken and intensify which will impact ocean sea surface temperature
weaker conditions- less upwelling stronger conditions- more upwelling normal - convective circulation
If there is a buoy sitting offshore, you might notice that it doesn't move closer to shore.Why?
wind driven Waves of water do not move horizontally, they primarily move up and down.
Inland vs Island
•A comparison of an inland climate (Nagpur, India) and an island climate (Honolulu, Hawaii) •Both at 21°N •Due to the ocean having a high heat capacity, it acts to modulate island climates •Island climates have a more consistent temperature year-round •Island climates have a smaller diurnal (of or during the day.) temperature range
Review -Series of Thought Experiment
•Ability to link a climate perturbation to a resulting perturbation •Melting polar ice •Large-scale land-use change •Hadley expansion •Positive feedbacks •Negative feedbacks
Pressure Gradient Force
•Air motion, the phenomenon we call wind, is the result of horizontal differences in air pressure .•The pressure gradient force tries to move air (wind) from *high pressure* areas *to low pressure areas* .•This greater the difference between high and low pressure, the stronger the motion
Paleoclimate
•Based on the reconstruction of past climates, scientists generally believe that over much of the Earth's geologic history the global climate has been warmer and wetter than the present •Global temperatures early in Earth's history were 8°to 15°C warmer than today •For about the past 500 million years, the poles have been ice-free for ~90 % of the time •During the past 1-million years, earth's climate has been characterized by glacial and interglacial episodes
There is a surplus of energy in the tropics and a deficit near the poles.•So why are the tropics not getting constantly warmer?
•Because excess heat is moved poleward
Vertical Density Section of the ocean
•Because the ocean is heated from above, low density water sits on top of high density water •This layering of the ocean is called stratification
Climate Modelling -They are Validated
•Climate models show an increasing ability to simulate the current climate and its variations •Due to a combination of increased model resolution and improved physical parametrizations •The availability of appropriate observational data is a critical factor in the validation (and improvement) of climate models
ENSO
•El Niño-Southern Oscillation (ENSO) is an irregularly periodical variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean .•The two phases, El Niño and La Niña, are related Walker Circulation strength. weaker conditions- el nino stronger conditions- la nina
Anthropogenic Emission Sources2
•It is important to know which sectors are growing most rapidly in their contribution to anthropogenic greenhouse emissions• Comparing emissions rates during the middle of the past decade with those at the beginning of the 1990s: Largest absolute increase hasbeen in the energy sector• Transport and forestry have shown similar percentage increases in emissions over this time frame
Latent Heat Flux
•Latent heat flux is the energy released or absorbed during a constant-temperature process •Phase changes, typically associated with evaporation and condensation •Main components to evaporation •Bare soil evaporation: Evaporation of soil moisture without help from plants. •Interception loss: Evaporation of rainwater that sits on leaves and ground litter without ever entering the soil •Snow evaporation: sublimation from the surface of the sno
Observed Land-Ice Change
•Melting of glaciers is not just a polar problem, it is a global problem •The rate at which glaciers are melting has accelerated over the last decade •The loss of ice from glaciers has contributed to the observed rise in sea level •In many areas, glaciers provide communities and ecosystems with a reliable source of streamflow and drinking water, particularly in times of extended drought and late in the summer, when seasonal snowpack has melted away
Adaptation vs Mitigation
•Mitigation -reducing and stabilizing the levels of heat-trapping greenhouse gases in the atmosphere •The goal of mitigation is to avoid dangerous human interference with the climate system, andstabilize greenhouse gas levels in a timeframe sufficient to allow ecosystems to adapt naturally to climate change •Adaptations -adapting to life in a changing climate -involves adjusting to actual or expected future climate •The goal is to reduce our vulnerability to the harmful effects of climate change (Sea level rise, extreme weather events and food insecurity
Ocean acidification
•Ocean acidification is the decrease in pH of the oceans •Carbonic Acid is formed by CO2 mixing with water •H2O + CO2= H2CO3 •Potentially harmful consequences for marine organisms •Metabolic rates •Immune systems •Coral bleaching •Threatens ocean food chains
Large-scale Land-use Change
•We know that if the Amazon Rainforest is cut down, LAI will decrease •Evapotranspiration decreases •Precipitation decreases •Increased incoming radiation •Sensible heat flux increases •Decrease in evaporative fraction •PBL becomes warmer and drier •LCL increases in altitude •Convective precipitation decreases as conv. precip decreases precip decreases = pos fb loop
Land vs ocean
•Ocean has a much higher heat capacity than land. •Water "flows" while the land surface is fixed. Ocean can transport much heat laterally, land cannot. •Ocean, obviously, is wet (evaporation is not limited by lack of moisture). Land can be wet, dry, or somewhere in between (moisture limitations can impede evaporation, alter the partitioning of energy). •The upper layer of the ocean is well mixed, so the surface characteristics are sufficient to define its interaction with the atmosphere, but soil has vertical structure and overlying vegetation. Heat conduction and moisture transport below the surface become important.
The Water Cycle in One Equation
•P = E + R + △S Precipitation Evapotranspiration Runoff Change in storage
PBL Growth
•PBL growth, development and properties are determined by •Moisture •Helps to provide the energy for instability •Heat •Helps to provide the growth and vertical development
Mitigation in the US
•Reduce burning of fossil fuels for electricity, heat or transport •Increased solar power •Increased use of hybrid vehicles
Adaptation in the US
•Taking advantage of increased growing season length and potential increase of crop yields •Seawalls for increased sea level
Observed Polar Ice Change
•Temperature in the Arctic has increased at twice the rate as the rest of the globe •Expected to increase an additional 8°C (14°F) in the 21st century •Winter temperature has increased more than summer temperature •A trend that is expected to continue •Grows in the winter and melts in the summer
Why does heat move poleward
•The Earth has a meridional circulation that moves air poleward .•The circulation in the tropics, Hadley Cells, moves warm moist air upward and then towards the poles .•The major driver of this circulation is solar heating. •Thermally direct
Southern Oscillation index
•The Southern Oscillation Index (SOI) is a standardized index based on the observed sea level pressure differences between Tahiti and Darwin, Australia •A measure of the large-scale fluctuations in air pressure occurring between the western and eastern tropical Pacific •A smoothed time series of the SOI correspond very well with changes in ocean temperatures across the eastern tropical Pacific •Prolonged periods of negative SOI values coincide with abnormally warmo cean waters across the eastern tropical Pacific -El Niño •Prolonged periods of positive SOI values coincide with abnormally cold ocean waters across the eastern tropical Pacific -La Niña
Atmospheric Composition
•The four most abundant atmosphericgases: •Nitrogen -78.08% •Oxygen -20.95% •Argon -0.93% •Carbon Dioxide-0.038% •The most abundant greenhouse gases in the atmosphere: •Water Vapor •Carbon Dioxide •Methane •Nitrous Oxide •Ozone •Chlorofluorocarbons (CFCs)
PBL -Diurnal Cycle
•The mixed layer (PBL) •Begins to grow at sunrise •Max depth in afternoon •Collapses around sunset •Weak mixed layer •Remains after sunset through the night, as it gradually entrains PBL properties into the free atmosphere •Inversion (Nocturnal boundary layer) •Begins to grow as surface heating stops around sunset •Marked by temperature inversion with height -very stable •Very little entrainment at top, unlike mixed layers. •Entrainment mixing occurs between mixed layers, free atmosphere
Carbon in the ocean
•The ocean contains around 36,000 gigatons of carbon •Mostly in the form of the bicarbonate ion •CO2is absorbed from the atmosphere at the ocean's surface •Converted in Gross Primary Production by phytoplankton •Some of the organic carbon then sinks into the lower ocean •Thermohaline moves deep ocean carbon along the bottom and then eventually brings some back to the surface
Thermohaline Circulation
•The thermohaline circulation, also called the global conveyor belt, is a large-scale ocean circulation •The thermohaline circulation plays an important role in moving heat poleward •Helps in regulating our climate
Walker Circulation
•There is a pressure gradient of high-pressure near the eastern Pacific and low-pressure near southeast Asia. •This is caused by differences in heat distribution between ocean and land. •This is a zonal circulation •Moves along constant lines of latitude •Because this circulation is near the equator, Coriolis effect does not deflect this motion
Oceanic Heat
•Water has a high heat capacity •Ocean water: ~4.1813 J/kg/K •Air: ~1.012 J/kg •The upper ten feet (~3 meters) of the ocean holds as much heat as the entire atmosphere The oceans have tremendous thermal and dynamical inertia •Reduces the daily and annual range of coastal temperatures •Global summer and winter seasonal temperatures extremes lag several weeks behind the annual track of the sun •Can slow and dampen the rate of climate change
Climate Modelling -Climate Change
•We know that humans are altering the climate •Climate models cannot replicate our current climate with natural factors alone, human changes help to explain what is occurring •If we can replicate the current impact of GHGs in the climate, can we model the future impact of GHGs?
Increasing GHGs
•We know that when GHG concentrations increase, that temperature will increase •Polar ice melts •Albedo decreases near the poles •Increased absorbed solar radiation •Increased temperature •Increase melting •Local ocean water density decreases •Less local sinking of water •Thermohaline Circulation slows down •Decreased poleward heat transport by the ocean •Increased polar ice increased temp/melting -> polar ice melts = positive fb loop increased polar ice ->polar ice melts = neg fb loop •Decreased poleward heat transport by the ocean •Increased polar ice ^^ The Thermohaline Circulation is not expected to slow enough for the last two items to actually happen
Stable vs Unstable Atmosphere
•Weather is strongly affected by how stable or unstable the atmosphere is .•In a nutshell, if we compare the temperature of an air parcel to the temperature of air surrounding it, we can tell if it is: •Stable -likely to remain in place •Air parcel is colder or has the same temperature as the surrounding air •Unstable -likely to rise •Air parcel is warmer than surrounding air •The greater the instability of the atmosphere, the more extreme the weather will tend to be
Weather vs Climate
•Weather is the way the atmosphere is behaving at a given moment in time •Weather consists of the short-term (i.e. days to weeks) changes in the atmosphere •Temperature, humidity, precipitation, cloudiness, wind •The conditions you feel when you walk outside •Weather can change from minute-to-minute, hour-to-hour, day-to-day, and season-to-season •Climate is the average of that weather•Climate is the description of the long-term pattern of weather in a particular area •Climate is what you expect, weather is what you get •Warmer in the the summer •Cooler in the winter •Climate change describes changes in long-term averages of daily weather
Evaporation -Precipitation
•When E-P > 0 •There is more evaporation than precipitation •More water is being removed than added •Salinity is higher •When E-P < 0 •There is more precipitation than evaporation •More water is being added than removed •Salinity is lower