Energy in the Earth System
According to the CSET test guide, there will be a total of 50 mutliple choice questions and three constructed response questions for CSET 122.
a. Compare the amount of incoming solar energy, the Earth’s internal energy, the energy used by society, and the energy reflected back to space
A black body (black rock), and you heat it, it starts emitting energy. Like, as a hot nail, it glows in the red because that that temperature, it is in the red portion of the spectrum. And continue heating it and it turns orange, then red, onto white. As temperature increase, the peak of energy radiation peaks towards shorter and shorter wavelengths. So, at temp of 6000 degrees K, the max happens to be in the visible spectrum. Organisms evolved eyesight to take advantage of the maximum amount of energy and that's why are eyesight is in tuned to the visible portion of the spectrum. Now the sun provides tons of very short wavelengths and oodles of high wavelengths of energy. The ones we see is just in the small portion of the visible wavelength spectrum. THe earth is also black body but at a much lower temperature. At 6000K (sun) and earth is 300K. So, earth peak of radiation is about 10 micrums, the thermal inferred portion of the spectrum. THe sun is beaming to us peaking at the visible and we are radiating back to the universe but at the 10 um. The earth is like a filter, allows passage of some wavelengths but not others.
Black body radiation:
-All bodies radiate energy
-the dominant wavelengths of radiated energy are a function of the temperature of the radiating body.
-So, the hot glowing body will have the tensity to emit most of it's energy in the visible portion of the spectrum, whereas a cool body, like the earth, will emit in the thermal portion of the spectrum.
Part of the solar radiation is backscattered by molecules. Backscatter light is not a directed beam, it's going everywhere. The best backscattering happens in the blue portion of the spectrum. So, sky is not blue, but because the light that is being diffuse is in the blue portion of the spectrum. Some of the solar radiation makes it through and is absorbed by water vapor, dust, ozone, h2S, so4, etc. With enough energy to that molecule and at just the right wavelength, the hydrogens will start to separate and vibrate and will consume part of the energy. Same with o3 molecule. They start vibrating. So, water is the big player, it absorbs fair amount of energy. Some energy is reflected by clouds. Clouds have a high reflective, albedo. The ocean has a very low albedo, it absorbs quite a bit energy. So, some hits the surface of the ground. The high albedo of the clouds look white because they are reflecting all of the visible portion of the spectrum. The deserts have relatively high albedos. The green portion has been lost (the red has been absorbed by the plants but reflects the green). Poles have high albedos, reflects back quite a bit. Then you have the dark water. Water is not a good reflector. Of everything that is on earth, the ocean has the lowest albedo. They are the ones that absorbs the most.
Albedo= Reflected energy/incident energy
So, Albedo ocean= 0.3 to 0.5, third to half of what is incident is reflected
Albedo land = .6 to .8 (80% is reflected)
Albedo snow/clouds= .7 to .9 (90% is reflected)
Absorbent bands of different compounds with respect to different wavelengths. Remember that the sun happens to emit most of its energy in the visible potion of the spectrum. It turns out that many of the compounds like water carbon dioxide has a transmission window. So the energy that is produced at that wavelengths does not resonate. So, accordingly, energy can pass through the atmosphere at that particular wavelength. So, a fair amount strikes here. Good for us. Water lets the visible potion radiate through. On the other hand, the earth emits around the 10 micrum. So, at 6 spectrum, it would be completely absorbed there. Co2 doesn't do much here. Oxygen, happens to have a peak right around 9 micrums, so oxygen absorbs any energy that comes through them. So, as the energy goes out, it finds all these filters (water co2 o2, takes a chunk. The molecules absorbs and radiates it back around the 10mincrum spectrum). Note that the water window is a relatively narrow one. The emission spectrum was a broad one. Water is the main greenhouse gas as it absorbs a lot of energy.
So, some of the incident energy is reflected and a good part is absorbed. 50% is absorbed by earth's surface And of that overwhelmingly the ocean (lowest albedo). 20% is absorbed in the atmosphere. So, 30% is reflected back into outer space.
Heat budget of the Earth:
50% absorbed by the oceans
20% absorbed by the atmosphere
30% is reflected back into the outer space
Emission by the ocean- 10% net
- evaporation- in evaporation, energy that is in the molecules in the water kind of contributes to the quick outgoing of molecules into the atmosphere. That molecules is carrying a lot o energy. So, that little molecules is a little energy package. Also, when it condenses into a cloud, it will give away that heat. So, it's a very efficient way of transferring energy.
- radiation- black body radiation, would see glow of earth in that wavelengths.
(no real straight conduction from ocean to atmosphere. Don't see leaping streams of water moving into the ocean. You see conduction in the ocean and atmosphere, but at the boundary there is no easy way to transfer energy from one to the other, So it uses these two methods)
Emission by the atmosphere - 60%
-the atmosphere has its own budget of energy. The ocean passes some of it's energy from the oceans to the atmosphere. So, now it has two sources, from what it gets from the ocean and from the solar radiation.
Emission of heat flux. 30%
Inside of the earth is very hot, the outside is very cool. So, heat flows from hot portions to cool, so inside is continuously losing heat.
9% of heat is net loss of the oceans into the outer space. Then you have the emission of the atmosphere and that is 60%. 30% from the inside of the earth is lost to outer space.
b. Describe what happens to incoming solar radiation as it relates to reflection, absorption, and photosynthesis
The atmosphere is quite transparent to incoming short-wavelengths of the solar radiation. On an average, approximately 20 percent of the solar energy reaching the top of the atmosphere is absorbed at Earth's surface. Another 30 percent is reflected back into outer space by atmosphere, clouds, and reflect surfaces (snow, water). 5% is backscattered to space by the atmosphere. The remaining 20 percent is absorbed directly by clouds and the atmosphere's gases.
The solar radiation's wavelength and nature of the intervening material helped to determine whether the incoming solar radiation will be scattered, reflected, or absorbed. These percentages vary due to factors such as cloud cover (if the sky is overcast, a much higher percentage or light is going to be reflected back into space than if it is a clear, sunny day).
c. Explain the mechanism and evaluate the significance of the greenhouse effect
Approximately 50% of the incoming solar radiation is absorbed by earth's surface and absorbed. Most of this is reradiated back into space. Because earth has a much lower surface temperature, the wavelengths that it emits has longer wavelengths than solar radiation. Thus, the atmosphere is an efficient absorber of the longer wavelengths emitted by earth (called terrestrial radiation). Water vapor and carbon dioxide are the two principal absorbing gases, with water vapor absorbing five more than the other gases and accounts for the warm temperature in the troposphere. When the gases in the atmosphere absorbed terrestrial radiation, the gases warm up and eventually radiates this energy away. Some of this energy travels skyward to be reasboved by other gas molecules, or travel back down to be absorbed by the earth. Thus, the earth's surface is constantly being heating either through solar radiation from the sun or from the atmosphere. Without this heating from the atmosphere, life would not be suitable or habitable for humans or some life.
This phenomenon is known as the greenhouse effect. In short, greenhouse effect is caused by the gases, water vapor and carbon dioxide, which absorbs short-wavelengths and converts it to long-wavelength energy, which causes the wavelengths to now be trapped within the atmosphere and the earth.
d. Differentiate among greenhouse conditions on Earth, Mars, and Venus; the origins of those conditions; and the climatic consequences of each
Greenhouse effect on Mars: For much of it's first billion years of existence, it is thought that Mars was a warm and wet planet. Now, Mars appears to be a lifeless, frozen wasteland. Because Mars did have active volcanoes at one point, it is thought that the outgassing from the volcanoes helped provide atmospheric gas to form a thick atmosphere. Much of the gases from the volcanic eruptions were water vapors and carbon dioxide (similar to volcanic outgassing here on Earth), which would have warmed the planet. If the amount of gas produced by the volcanoes were similar to the amount on Earth, than Mars may have had enough water to fill oceans. Heat from meteorite impacts would have also helped release water vapor into the atmosphere, helping to enhance the greenhouse effect. At one point, carbon dioxide was lost and the greenhouse effect became weak until eventually the planet froze over. Some of the carbon dioxide condensed and froze to make the polar caps while others were bound to surface rock. The majority of the carbon dioxide was lost to space, although it is not clear as to why. One theory is that as Mars cooled, the magnetic field in the core (like on Earth), became weak as the core began to harden. Because the magnetic field became weak, the solar wind particles were able to strip the atmosphere and blow it into space.
Greenhouse effect on Venus: Why does Venus have such a strong greenhouse effect? Mainly, it's due to the large amounts of carbon dioxide in Venus' atmosphere, with approximately 96% of its atmosphere composed of carbon dioxide (200,000 times that of the Earth's atmosphere). However, we know that Earth and Venus have similar sizes and composition. So, what happened on Venus that allowed it to have such a high amount of carbon dioxide in its atmosphere. One main difference is that Venus has hardly any water. Another big difference is that Earth doesn't have a lot of carbon dioxide in its atmosphere. On earth, the ougassing of water from volcanoes condensed into rain, eventually forming the oceans. In addition, carbon dioxide on Earth dissolved in the ocean and eventually was locked away in rocks. It was measured that Earth has about 170,000 times as much carbon dioxide trapped in rocks than it has in its atmosphere. So, looking at the figures, we can see that Venus and Earth actually has the same amount of carbon dioxide. The difference is that on Venus, it is in a gaseous stage in the atmosphere whereas on Earth, it is stored in rocks. So, if all of the carbon dioxide was to be released into our atmosphere, then Earth would become as hot as Venus.
The other difference between Venus and Earth was water. Venus doesn't have much water on its planet. What little water was on Venus was baked away from the heat. Without any oceans on Venus, there was no way that carbon dioxide could dissolve and became trapped in the rocks. When water vapor was outgassed from volcanic eruptions, it is thought that the UV light from the sun broke apart the water molecules. The hydrogen atoms escaped into space and the oxygen atoms was lost to chemical reactions. Venus also had a weak magnetic field which left its atmosphere vulnerable to the sun's solar wind (similar to what happened with Mars). After billions of years of breaking water molecules down into oxygen and hydrogen, this prevented the formation of oceans on land, thus, prevented carbon dioxide from ever dissolving and being stored within rocks. The oceans, from the start would have never been able to fully form, or was evaporated quickly, due to the high amount of sunlight that Venus receives. Venus would be around 113 F, below boiling point. But, this high temperature would increase evaporation of water from the oceans (if there were any). There would be more water vapor in the atmosphere. And, since water vapor is a greenhouse gas, it would have helped strengthen the greenhouse effect. The greenhouse would have then warmed the planet even more, increasing evaporation and water vapors in the atmosphere, which would then strengthen greenhouse effect even more. This cycle Is known as the runaway greenhouse effect. This cycle would continue until there weren't any more oceans left on the planet.
Even if we were to move Venus to Earth's orbit, Venus would still not be just like Earth because of its weak magnetic field. There is so much controversy over WHY Venus has such a weak magnetic field. One though is due to the fact that it has a very slow rotation (243 days). Its rotation is just not fast enough to maintain a global magnetic field. Thus, without a magnetic field, solar wind is able to penetrate the atmosphere and blow hydrogen gas off into space. Another theory is that Venus' weak magnetic field doesn't really have to do with its slow rotation. Basically, we still do not know for sure the reasons as to why Venus does not have a magnetic field. If you are interested, there is a thread on physicsforum about this, or feel free to do more research on your own. :)
a. Assess the differential effects of heating on circulation patterns in the atmosphere and oceans
Coriolis Effect- happens only when you have a detached body that is moving over considerable distance over the Earth. Rotates every 24 hours, move moes 24 and equator congectular. Velocity is higher, equator moves much faster. Coriolis effect kicks in only if you're not moving parallel to the equator. Affects everything we do. Deflects due to change of the Earth. Solar energy hits earth differently so we'll always have temperature gradient. Big contribution is the Pacific, allows large passage of water from equator to poles.
Example: Flow of air, Flow of ocean
In northern hemisphere, movement will be deflected clockwise. Movement in the southern hemisphere deflected counter clockwise.
Wind Circulation in a Rotating Earth
WILL POST PICTURE
Deflectors, exchanges heath with another cell
WIND CIRUCLATIN PATTERNS
WILL POST PICTURE
Due to significant changes in density of air, cool air pushes down on warm air.
Trade winds that blow from Spain to South America. Equator to 30 degree latitude from Northeast
30-60 degrees winds blow south westerly winds
60-90 degrees, north easterly winds
Refers to wind fro whence it comes from. Easterly winds=from east to west
Westerlies from west to east
Surface-wind driven currents
Density driven water masses
upwelling/downwelling driven vertical circulation
Tides- minor net tranfer of mass
If you have winds blowing over the ocean, there's a frictional drag between the winds and the water. So, some of that force that is exercised by the wind is transferred into the water. And sort of irregularity of the water helps.
Stress is a function of a wind velocity and fetch.
Fetch is the area or distance over which a wind blows.
So, the wind is blowing and causing the water to move in that direction. The water itself is like a stack a books. The one ontop displaces the most and reduces as you move down due to less frictional drag. There is a decreases in the amount of displacement as you move further down into the ocean., away from where the stress is applied. So, the Coriolis effect will come into play because of the rotation of the Earth. In the Atlantic Ocean, if you have a ship leaving Spain, the wind blows and drives ships towards the Caribbean. On the other hand, if you have a boat leaving Boston barer, you have the westerlies pushing the ship over. So, the current in the ocean, if driven just by the winds, but you also have the Coriolis effect that causes the water to turn to the right. There is an added affect that affects oceanic circulation and Coriolis effect. Frictional drag also comes into play. Wind blowing down, the layer of water underneath it is subject to the Coriolis effect, so the water is deflected to the right. The top current displaces the water underneath it. That water, too will be deflected to the right by the top current (second current). And this second current then deflects the bottom the current to the right. And so on. Kind of like a spiral effect as you go further down into the ocean. This is called the Eckman Transport Effect + Coriolis is responsible for the fact that currents to not tie themselves into a knot. The first surface layer that is deflected at 45 degrees. The net angle movement is at 90 degrees to the wind. Water is being moved to the right at the direction of the wind. So, if you have the wind blow down from Spain down towards the equator, then the mass is concentrated to the right. And the same with wind blown from US towards Spain. This creates a bulge. It forces a gravitational movement towards the outside. A pressure that forces the water away from the bulge, always to the right due to Coriolis effect. So, the surface wind current is forced to go around the bulge because it cannot climb up the bulge. So, the net result is a bit gyro that goes around the central bulge.
b. Relate the rotation of Earth to the circular motions of ocean currents and air in low- and high-pressure centers
c. Compare the causes and structures of various cloud types, precipitation, air masses, and fronts, and the causes and effects of different types of severe weather
Air Mass: An air mass is the volume of air that covers a large part of the continent or ocean and acquires characteristics from the surface below. Meaning, air over a continent will be drier than the air over the ocean. Air over a continent will also be warmer in the summer and cooler in the winter. Air mass extends from the surface of the Earth all the way up to the end of the tropopause. The names of air masses are based on where they developed: The moisture content of an air mass is related to its temperature. Air masses are commonly 1600 km (1000 mi).
Continental: air mass that forms over land
Maritime: air mass that forms over the sea
Then, we have air masses that forms at certain latitudes. Air masses could be arctic, polar, tropical, or equatorial.
So, to describe an air mass, you look to see at what latitude it formed and whether it was over land or sea. There are seven types of air masses:
1. continental arctic (cA)- These form in stable air, are extremely cold and dry. Provides record breaking cold temperatures due to the fact hat they form in the polar where they receive 24 hours of darkness in the winter time.
2. continental polar (cP)- These produce cold and dry air in stable air. They are not as cold as the cA air mass. The form further south and dominate the weather in the US during winter time. When cP moves soutward from Canada into US during summer time, it passes over warmer land. As a result, the thermal contrast across the cold front decreases. This is an example of frontolysis.
3. continental tropical (cT)- Produces hot, dry air. Brings record heat. Forms over the desert southwest and north Mexico during sumer. Brings record heat to the plains and the Mississippi Valley during summer. Moisture evaporates into the air, making it more like mT air mass. Rare in winter. Has the highest surface temperature.
4. maritime arctic (mA)- Cold air mass that forms over the arctic. Acquires moisture as it moves south over the cold waters of North Atlantic and North Pacific Oceans. The difference bewteen maritime arctic and martime polar is that martime polar moves further out into the ocean and becomes more warm and moist than mA air.
5. maritime polar (mP)- Not as cold as cP. Produces cool, moist air and brings cloudy, drizzly damp weather. Forms over North Atlantic and North Pacific. Forms anytime in the year.
6. maritime tropical (mT)- Forms in unstable air. Produces warm, moist air. Most common along the eastern USA. Originates over southern Atlantic and Gulf of Mexico. Forms year round. Responsible for humid days in the south and east. Brings convectional rainfall to the southern US.
7. maritime equatorial (E)- There is no continental equatorial air mass because there is no land mass in the equatorial region that is large enough to produce an air mass.
Continental Polar and Maritime Tropical have the most influence on the weather in US. The US is not a favorable source region because of the relatively frequirent passage of weather disturbances that distrupts any opportunutiey for an air mass to take on the properties of the underlying region.
Lake-Snow Effect: Cold Canadian air, associated with cP, moving over the relatively warm Great Lakes is often responsible for the Lake-Snow effect. May result when cold, dry air moves across the relatively warm waters of the lake.
Nor-easter: have strong winds out of the northeast, pulling in mP air along the Atlantic Coast.
Tornadoes: Although erratic in their pathways, are always characterized by high pressure. Forms primarily during spring-early summer time because there is a huge contrast in temperatures between cold, dry Canada and Warm, humid Gulf of Mexico. They are associated with cumulonimbus clouds, occur in advance of a cold front of a mid-latitude cyclone, and move generally southwest to northwest.
Hurricane: Destruction is made worse when the storm surge, which is not prominent in all hurricanes, is present. Hurricanes that affect North America are more prevalent during September.
Thunderstorms: A distinguishing feature of thunderstorms is their anvil top. Violent convective storms accompanied by thunder and lightening. Most common in the central and southern states as these regions are open to invasions of warm, moist subtropical air from the Gulf of Mexico. Thunderstorms form most often in warm, moist unstable air when vertical currents develop over heated ground.
Anticyclone: Stable anticyclone acts as a block to moving cyclones.
Cyclone: Moves cold air towards the equator and warm air poleward. The termpture contrast on either side of the polar front serves as a source of potential energy for developing cyclones. Cyclones derive energy from latent heat released by condensing water vapor. Innermost isobar encircles the zone of lowest pressure.
Mid-latitude Cyclones: Are the cause of most of the stormy weather in the US, especially in the winter. Low pressure. A warm sector of a mid-latitude cyclone experiences a southerly windflow. Develops along a feature called the polar front.
Front: When two air masses meet up, they do not merge or mix due to the fact that they are at different temperatures, they have different densities. Instead, the denser air moves beneath the less dense air, causing it to lift away from the surface. The boundary between two air masses is called a front. A front is named for the air behind it. So, if a warm front moves and replaces cool air, it's called a warm front. And, a cold front brings cold air. Fronts start at the ground and extends upward, often all the way up to the tropopause.
Cold Front: Cold fronts travel at a speed of around 22 mph. With a cold front, the denser cool air forces the warm air to rise steeply upward along the line of the front. As a result, strong convection currents develop, which leads to the development of storm clouds (cumulus-type clouds) and heavy rainfall. Cold fronts are associated with a high-pressure system, called an anticyclone. Advances rapidly and brings violent weather. Cold front's slope is steep- 1:100. Cold front's are steeper slope than warm fronts because cold air has a higher density, which allows it to hug the ground. This slows down the advancement of the lower portion of the front.
Warm Front: Warm fronts travel at a speed of around 15 mph. Warm air rises over cold air more gradually. Moisture condenses as the warm air moves up and produces clouds (thick rain clouds at the lower elevation and thin, stratus-type clouds at higher elevation) and precipitation. The types of clouds depends on how rapidly the warm air moved over the cold air mass. Warm fronts are associated with a low-pressure system, called a cyclone. The wind often comes from the south to southeast direction. Warm fronts often proceed cold fronts as the low pressure systems spin counterclockwise. When warm air mass gently rises over cold air mass, then it forms cirrus clouds first at high altitudes, followed by altostratus, and then stratus clouds. Cirrus clouds often signal this front is on the way. Average slope is about 1:2000. A series of high, middle, and low clouds form in advance of the surface position of a warm front. As warm front passes through a region, temperature gradually rises. Precipitation on warm fronts take place before the grown-level position of the moving front. Warm front weather lasts longer than a cold front weather because a warm front has a low angle slope and covers a greater area with its weather. In addition, because of its slow speed it also covers a large area of land with its weather for a considerable length of time.
Occlusion: Because cold fronts move faster than warm air fronts, it will eventually overtake the warm front and lift it off of the ground. This event is known as an occlusion. Warm occlusion occurs when the cold front rises over the warm one. A cold occlusion occurs when the cold front undercuts the warm front. Complex weather patterns take place here.
Stationary Front: Indicated on a map with both semicircles and triangles on either side. When warm and cold fronts meet up, neither is strong enough to replace the other. Clouds, prolonged precipitation, and storm trains can be found here. Stationary fronts will either dissipate or change into a cold or warm front. The Rocky Mountains help to lead the development of stationary fronts when shallow cold air mass from Canada cannot move over the mountains.
Uprunning: Warm air gliding up along a cooler or cold air mass.
High Pressure Systems: Because cold air's molecules are closer packed together, it becomes more dense and begins to sink. As the air sinks, the rotation of Earth deflects this air in a clockwise direction called the Coriolis Effect. As it sinks, the air begins to warm up. It loses moisture and dries up. This creates an area of high pressure at the surface and brings weather of cloudless skies. The region is dry and sunny in summer and cold and frosty in winter.
Low Pressure Systems: The warmth of the air at the surface causes air to rise and produces low surface pressure. As air rises, the amount of water vapor it can hold decreases until it becomes saturated and water droplets form. The temperature at which water vapor condenses is called dew point. The temperature at which water vapor condenses varies. As water vapors condenses, it produces clouds and precipitation. The type of cloud depends on how rapidly the air rises. Weather in a low- pressure region is usually cloudy and windy.
Winds that blow in low-pressure regions are typically stronger than the winds that blow in high-pressure regions because the pressure gradient is usually steeper around low-pressure systems.
Clouds form when air rises and condenses into water droplets or freezes into ice crystals. The elevation at which this takes place depends on the amount of moisture in the air and the stability of the air. Cold clouds form at high altitudes contains only ice crystals. Warm clouds form at lower-altitude and contains only water droplets. Rain drops that falls from these types of clouds are warm. The rain they produce is a called no-freeze rainfall. A mixed cloud contain both. Snowflakes form when ice crystals and water droplets cool to below freezing. Water evaporates for the droplets and is deposited on the ice crystals. These ice crystals collide and form snowflakes. Fog and dew from when condensation that occurs at ground level. If temperature happens to fall below freezing, then the dew is replaced by frost.
Air can be forced to rise in three different ways:
1) Through Convection: When the air is heated as a result of contact with a warm surface. This forms small fair-weather cumulus or cumulonimbus clouds. May produce showers and short-lived storms.
2) Orographic Lifting: Moving over a mountain causes the air to rise, cool and condense into water droplets. This results in orographic cloud formation. Orographic lifting produces frontal clouds of rain and drizzle.
3) Warm air rises when a cold air mass pushes beneath it at a weather front. This action forms frontal clouds. If the clouds are thick enough, then water droplets and ice crystals join together and falls as precipitation.
The height at which water vapor condenses in a rising air mass marks the cloud base.
Cloud types differ in appearance and develop at different heights. Luke Howard, who was an English pharmacists, classified the different kinds of clouds based on the heights at which they develop. The names that he coined were:
And each type of cloud is grouped as high, middle, or low level based on what height the cloud base most often occurs in. Clouds are grouped into 10 basic types:
High Level Clouds:
cirrus- Forms worldwide and all year long. These high-level clouds consists entirely of ice crystals. The clouds are thin and wispy. Once the ice crystals have grown large enough, they drift down until a wind blows it in the direction it is moving in, stretching the cloud into long tails that curls (hence the name cirrus, which means curl). Cirrus clouds are produced from stable wind lifting up along a weather front. As the air rises, different types of clouds forms along the way as more and more moisture condenses. Cirrus is the last cloud to form. The air above the region where cirrus clouds forms is very dry.
Cirrostratus- Forms worldwide and all year long. They are associated with warm fronts. Consists entirely of ice crystals. These types of clouds will produce halos around the sun or moon, which is an indicator that rain is about to come.
cirrocumulus- forms worldwide and all year long. Cirroscumulus clouds are associated with cold fronts. They consist entirely of ice crystals. Has a fibrous appearance, like the other cirrus type clouds. Cirrocumulus actually began as a cirrus or cirrostratus that was reshaped by wind movement.
Medium Level Clouds:
altocumulus- These form worldwide and all year long. They are associate with cold fronts. Composed primarily of water droplets
altostratus- May form worldwide and is most common in the mid-latitudes. They form all year round. Altostratus clouds are associated with warm fronts, especially in temperate climates. Contains ice crystals near the top of the cloud and water droplet further down. Forms at warm fronts, where warm moist air is being lifted above the cooler air. Usually can find cirrostratus ahead of the altostratus cloud. These types of clouds results in rain or snow.
Low Level Clouds:
nimbostratus- Forms worldwide and all year except in Antarctica. These types of clouds may produce steady rain or snow. Depending on the temperature, these clouds may consists of all water vapors or it may be a mixture of water at the bottom on the cloud and ice at the top, or it may consists primarily of ice. Associated with warm fronts.
cumulonimbus- these clouds are found worldwide, expect in Antarctica. They form all year and are associated with tropical cyclones and thunderstorms. These types of clouds has the greatest vertical height and may even extend beyond the tropopause. These types of clouds are made up of liquid droplets in the lower region and ice crystals at the top. They produce thunderstorms, hailstorms, tornadoes, heavy rain, and snow. These clouds are formed through convection currents in unstable air. As warm, moist air rises rapidly, it cools and its moisture condenses, releasing latent heat and worms the air, so it continues to rise. Air is drawn into the cloud to form upcurrents, with speeds reaching up to 100 mph. Ice crystals and hailstones fall down through the cloud and produces downcurrents that exits the cloud as strong winds. This cools the air adjacent to the upcurrents, which will eventually suppress the upcurrents. Convection begins to cease and the clouds begins to dissipate. Cumulonimbus clouds are very short-lived. As the clouds begins to dissipate, it may release tons of moisture all at once in a very large storm cloud. Cumulonimbus clouds may also develop into a tornado. Associated with cold fronts.
cumulus- these types of clouds are found worldwide but is common in humid regions. They form all year round, but mostly in the summer. Cumulus clouds form by convection. They form in the columns of rising air called thermals. As air rushes upward, a thermal draws in the surrounding air at the sides and at the base. This action mixes the clouds with dry and cool air. Cloud droplets evaporate in the drier air, and fragments of the cloud sink into the cool air. This action prevents cumulus clouds from growing wider at the sides. It also prevents other clouds from forming close to it, which is why cumulus clouds are found in patches in the sky, separate from each other.
stratus- found worldwide but is most common near mountains and coastal regions. They form all year round, but mostly during the winter months. Forms a gray layer that covers most of the sky. Made up of liquid droplets. When stratus forms at ground level, then it is called fog. There is no vertical air movement, so stratus clouds only produces drizzle or snow grains. They form overnight in fine weather, particularly over water. It generally dissipates in the morning when temperature rises and the cloud droplets evaporate. Frontal stratus forms along warm fronts, as warm air slowly moves up by the cooler air. Cirrostratus and altostratus are formed first, then stratus clouds.
Stratocumulus- these clouds are found worldwide and are formed all year round. They are composed of liquid water vapors. These types of clouds form patches, sheets, or layers of white or grayish clouds. These types of clouds form when rising air meets up with warmer air and is pushed up, flattened on its underside.
Some of the cloud types are further divided into subgroups, such as humili, congetus, lenticularis, and undulatus.
d. Know and explain features of the ENSO cycle (El Niño southern oscillation, including La Niña) in terms of sea-surface and air temperature variations across the Pacific, and climatic results of this cycle
The ENSO cycle refers to the periodic changes in patterns that takes place in the Pacific Ocean. ENSO causes extreme weather conditions, such as flood or droughts, to occur in various regions of the world. The exact causes for these changes are still not fully understood.
Oscillation cycle: change in the distribution of air pressure over the South Pacific
El Nino: During El Nino, a warm oceanic phase takes place along with high air pressure along the western Pacific Ocean at intervals of between two and seven years and lasts for 9-12 months .The effects of El Nino becomes obvious towards the end of the year in December, and is associated with the changes in air pressure, known as the Southern Oscillation. This full cycle is called the El Nino Southern Oscillation event (ENSO) and includes La Nina (the opposite of El Nino). Under normal circumstances, pressure is high over the eastern South Pacific and low in the western. Trade winds are a result of the changes in air pressure and drives the Southern Equatorial Current, which is carrying warm water away from South America and towards Indonesia. This results in heavy rain over Indonesia and dry conditions along Peru and Chile. Well, during ENSO, air pressure reverses or weakens, thus affecting the trade winds. The oceanic water begins to warm along the coasts of Peru and Ecuador. A much stronger warming appears that lasts for several months. This warming is accompanied by heavy rain falls over Peru and Chili causing the dry, arid regions to bloom, whereas Indonesia goes through a drought.
La Nina: The opposite takes place. The oceanic waters begin to experience an abnormally cool period in the central and east central equatorial Pacific. Air pressure is low. La Nina may last 1-3 years.
a. Analyze weather (short-term) and climate (over time) in relation to the transfer of energy into and out of the atmosphere
Climate refers to long term conditions of temperature and precipitation (or lack thereof)
Weather refers to transients (time dependent) changes in temperature and precipitation with velocity and wind direction. In general, geologist are concerned with climates.
Tracking weather is feasible through the use of stations (which measure barometric pressure, for example) and satellites. The folks who do the tracking of the weather are literally looking a a photograph of a hurricane as it moves, for example. There's a lot of meteorological stations looking at barometric pressure so they can track the movement of an airmass.
The coastal area is known for mild temperatures. Weather that is controlled by the ocean. The ocean is very large and the water has a very high heat capacity. It can receive a lot of energy and change is temperature little. Store an enormous about of energy. Solar radiation penetrates the ocean, most is penetrated, some bounced back, the surface interaction with the atmosphere, creates the waves and the energy is distributed through the mixed zone. The net result is during the day, the oceans are a lot cooler than the land. The land is fairly hot. During the night, the land cools significantly, but the ocean does not. Large temperature contrast between the land. The land starts to cool down whereas the ocean stays relatively warm. So the pressure of the land becomes a zone of high pressure. The air on top of the ocean, so in comparison it becomes low pressure. Zone of high pressure to a zone of low pressure (land breeze- cooling land to the ocean, when sun sets). Land keeps cooling more and more and more. Land has cooled significantly and get another rushed of land breeze around 5 in the morning. Fisherman take advantage of this land breeze to sale out to fish. During the day, things change significantly, the land heat up and heats the air above it. Becomes less dense. It is replaced by the air from the ocean. So, come 12 pm, you have a strong sea breeze, air coming from the ocean, so fisherman come back during this time, when the breeze will bring them back. So, during the day, you have winds moving from cool ocean to the land, and during the nigh, you have wind moving from the cool land moving to the warm ocean. This happens everyday. And since the ocean has an enormous amount of heat, you have balmy conditions of the coast.
So, you have surface-wind circulations dominated by relative temperature differences between the ocean and the land. At dusk and in the early hours before dawn, the land is cooling or cool and wind blows from land to ocean (land breeze). Whereas, in midmorning, ocean is cooler than land and winds blows from ocean to land (sea breeze). In coastal areas, they have mild climates because of the high heat capacity of the ocean, which buffers coastal temperatures.
In CA, we have a particular effect. We have upwelling of cold water. That upwelling basically inserts here in the middle a layer of cold water between the warm ocean and the warm land. Warmish water offshore, band of cold water, and the warming land. This warm air mass picks up moisture from the warming ocean water, then finds cold water, so it gives some of its heat to the cold water, so that leads condensing= fog. Forms between 8-11 in the morning, when the movement of the sea breeze is stronger. Coastal fog in California is formed as moisture laden sea breeze moves over the cold zone of upwelling.
There are basically three mechanisms to trigger precipitation:
Remember, the masses that comes from polar regions are cold whereas the masses from the tropical regions are warm.
1) Convective uplift
When you have high pressure zone on one side and low pressure on the other side. The high pressure moves towards the low pressure and is forced to rise. As this warm air mass rises, it cools and begins to fall back down, warming up again. As the air mass is forced up and cooled, it condenses and forms clouds. The ultimate condition of convection uplift are hurricanes.
2) Collision of air masses
a) Warm front (air mass) colliding with a cold air mass.
As a warm front collides with the cold air mass, the warm air is forced up at a low angle. As it rises, it condenses into clouds, from nimbostratus, to altostratus, to cirrostruats, to cirrus. Rain is light over a broad area.
b) cold front moving against the warm air mass.
As a cold air mass hits a warm air mass, it forces the warm air to rise rapidly up. This forms tall clouds (cumuloform clouds) and produces intense rainfall along the front area.
c) orographic uplift
Air that is coming from coast is forced to rise abruptly as it moves over the coastal ranges, that causes cooling of the air and then it comes down into the central valley. The air compresses to it warms up and then forced to rise again over the sierra so it's cold, makes it over the sierra and starts warming up again as it comes down over owens valley, then cools down again as it goes over white mountains and then warms as it comes down over great basin. Every times it rises, prescription forms. Over the Sierra, air goes very high and as soon as it starts cooling, Skiing in the west of the sierra is not that great as it's very moist snow. Very slushy. On the east side side, snow is bone dry. As the air goes down, air warms up and as the air sweeps over the central valley, it sucks the moisture out of the air (so why central valley is a desert). Same with Owens valley and great basin.
Same effect is found on islands. Winds blowing over ocean is wet and forced to rise over windward side of the island. But as soon as it goes over the mountain it starts drying, collecting moisture on the leeward side. Similar with Canary Islands.
these are a special case of convective uplift. The forms where a zone of low pressure forms due to heating of the ocean. Air is forced to rise and begins this whole zone of convention uplift. Hurricanes start north of equator, 5-10 degree north of the equator (Coriolis effect does have a minor effect, which is why we don't have hurricanes right at the equator). Notice there are no hurricanes south of the Atlantic. Called hurricanes in north Atlantic, and in the pacific they are called cyclones. Typhoons in southern pacific. All the same thing. Notice in the northern hemisphere the path is clockwise and in the southern oceans the path is counterclockwise.
Ice Age Mechanisms:
Currents are important for glaciation. With currents in the Atlantic, the transfer of heat provides livable conditions for england and Scandinavian. Warm currents are warming them up. The current is being deflected by Central America. Central America didn't exits 3 mya. It was under water. At that time, the ocean gyre didn't exist. The gyre was more like the circum antarctic current. There was no obstacle so it went straight from the Atlantic to the Pacific. Which means there was not the bathing of warm water here in the north. If you don't have the warm gyre you have very cold conditions. But, there is not enough moisture in the air. It's like in Siberia where it's brutally cold, but no moisture, there's only an inch of snow. So, what we think happened when central America was open was that we had cold, but not glacial conditions. The moment, it closes, we have the condition of warmth. With precipitation comes moisture and with moisture comes snow. That set the stage for whenever there were variations in solar radiation (dark spots = more solar radiation), so small changes in incoming solar radiation caused the growth of glacial ice. Right now we are interglacial. And it rains a lot (like in England). If it starts getting very cold, then icebergs will form and the gyre will be pushed further south, so the current will be deflected south. That will take away moisture form the northern hemisphere. So, it won't snow enough so the glacial will start retreating.
One could not have a glacial episode as long as central America was open, once it close then you have good conditions for glacial period.
b. Discuss and assess factors that affect climate including latitude, elevation, topography, and proximity to large bodies of water and cold or warm ocean currents
© Science CSET: Free Prep Guides, 2008. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Science CSET: Free Prep Guides with appropriate and specific direction to the original content.