Geography Test 2

What is advection fog?

Advection fog is the result of advection-the transfer of heat or matter by the flow of a fluid, especially horizontally in the atmosphere or the sea. It occurs in both warm and cold air but warm air is more common. It occurs over a cold ocean current or over cold land that is next to warm water (e.g. deep south in winter). When air in one place migrates to another place where conditions are right for saturation, an advection fog forms.

What is albedo?

Albedo is the reflective quality, or intrinsic brightnes, of a surface. It controls how much insulation the each receives. Darker colored surfaces have a lower albedo, and lighter surfacec have a higher albedo. Lower angle surfaces produce more reflection than do higher angles. Smoother surfaces increase albedo.

What are air masses?

An air mass is a vertically thick, horizontally extensive portion of the atmosphere that has similar temperatures and moisture content Air masses with such more or less uniform properties over large areas must be generated by source regions that are also large. Good source regions for uniform air masses generally require: 1) a fairly uniform surface (e.g. large plains, the ocean), 2) relatively little surface air movement o They can be characterized by two properties: 1) their general temperature level, 2) their relative moisture content o There are four main air-mass characteristics ♣ Polar (P)-cold ♣ Tropical (T)-warm ♣ Maritime (m)-wet ♣ Continental (c)- dry

What is atmospheric pressure?

Atmospheric pressure is the weight of an air column above a place, as measured in milibards or equivalents. Average atmospheric pressure is 1013 milibars. Atmospheric pressure decreases upward since ther is progressively less air above to press down onto the surface. This pressur pushes in on all of us.

What causes air to rise?

Rising air needs cooling for condensation to occur, but air does not rise if it is cooler (i.e more dense) than the surrounding air. May need a lift to get enought cooling for cloud. The main ways in which to make air rise is: free convection, forced convection-orograrphic lifting and frontal lifting.

What is saturation vapor content?

SVC is the amount of water air can hold at the current temperature. SVC increases as temperature increases.

What is sensible heat?

Sensible heat is the heat transferred back and forth between air and surface in turbulent eddies through convection and conduction within materials. About 1/5 of earth's entire net radiations is mechanically radiated as sensible heat from the surface, especially over land.

What is specific humidity?

Specific humidity is the ratio of water vapor content of the mixture to the total air content on a mass.

What is the stratosphere?

Stratosphere is a layer of the atmosphere that holds the ozone layer. Temperature increases with altitude throughout the stratosphere. Its outer boundary is called the stratopause. Measurements of ozone in the stratosphere are decreasing. It is heated by absorption of sunlight by ozone (primarily by UV absorption).

What happens if there is water in the landscape?

Transpiration occurs. Unless it's a desert, there would be vegetation which would be losing water vapor by evaporation when leaf pores are open to take CO2. So there would be a flux of latent heat to the atmosphere.

Which would heat faster: the desert or the forest?

Under the same radiation input, the desert would heat up faster than the forest because there is only air and the ground. The forest has a large portion of latent heat that is being released from all the vegetation. The desert doesnt have vegetation so the radiation turns into sensible heat.

Wha is upslope fog?

Upslope fog is a type of advection fog that is formed when moist air flows to higher elevations along a hill or mountain. This upslope lifting leads to adiabatic cooling by expansion as the air rises. Eventually it reaches the lifting condensation level. The resulting upslope fog forms a stratus cloud at the altitude where saturation occurs and condensation begins. Occurs on the great plains--ie pushing air up a slope, thereby cooling it.

What are upwelling and downwelling currents?

Upwelling currents= where surface water is swept away from the coast, either by surfacce divergence or by offshore wind. Are composed of cool water. Downwelling currents= occur in regions with an accumulation of water. The excess water gravitates downward in a downwelling current. These are the deep currents that flow vertically and along the ocean floor and travel the full extent of ocean basins. They redistribute heat energy and salinity over the globe.

What is relative humidity?

VC/SVC. Because SVC is in the denominator, the result is that warming reduces relative humidity and cooling increases relative humidity. In the absence of storms or fronts, relative humidty changes mainly because temperature changes.

What is vapor capacity?

Vapor content is the actual amount of water present under the current actual conditions.

What characterizes high and low pressure?

Winds spiral into lows and out of highs. Highs cover large areas. Winds deflect to the right (clockwise) in N. Hemisphere and deflect left (counter clockwise). This results in large spirals of wind around highs and lows. Clockwise winds around a high produce an anticyclone. Counter clockwise winds around a lows produce a cyclone.

Monsoons simplified

Winter is dominated by high pressure cell that builds and becomes stronger. This results in very little rain--air is cold and dry. Summer is dominated by a low pressure cell. The land mass heats and warm air begins to rise. The lower pressure cell draws in wet air masses from the ocean. Lots of rain occurs.

What drives global circulation?

intense tropical convection that creates hadley cells. The surface heats up in the tropics, causing rising wet air. Convection occurs and low pressure is left behind at the surface. The pressure spreads out in the troposphere and falls back to earth.

What is ground heating and cooling?

is the flow of energy into and out of the ground surface (land and water) by conduction.

What is orographic lifting?

o A case of forced convection by which air is forced to rise when blown against a mountain range, the windward side of the mountain is windy, the leeward side has a rain shadow. On the windward slope of the mountain, air is lifted and cooled, causing moisture to condense and form precipitation. On the leeward slope, the descending air mass heats by compression (adiabatic warming) and any remaining water in the air evaporates. Thus, air beginning its ascent up a mountain can be warm and moist, but finishing its descent on the leeward slope, it becomes hot and dry.

What is cold air drainage?

o Cold air is heavier, so it flows down hill and collects in valley bottoms. Creates a temperature inversion. o Cold air tends to sink

What are the requirements for severe thunderstorms?

wind shear, high water vapor content in lower troposhpere, mechanism to trigger uplift (e.g along a cold front), potential instability (vertical temperature structure, conditional instability)

What is the environmental lapse rate?

o The decreasing of temperature with increasing altitude, the cooling rate upward in the troposphere

What enhances percipitation?

releasing of latent heat in rising, cooling air makes air even more unstable and permits the builduo of more precipitable water in the air

What is a saturation deficit?

the amount of water that air can still absorb before becoming saturated. Is SVC-VC RH=vc/svc Warming increases SVC so it also increases the saturation deficit. The deficit is normally the greatest in the afternoon.

What do thunderstorms require?

1. Rapid upward temperature decrease such as surface heating 2. humidity which creates unstable air 3. updrafts that are triggered by surface heating or frontal activiy 4. Strong downdrafts that cause exceptionally strong winds near the ground. 5. upper air instability that permit tall clouds or clouds at the top.

What is the vortext structure?

1. A steep pressure gradient inward 2. Strong, spiraling updrafts around the central vortex 3. Downdraft in middle of vortex (low pressure)--eye of storm 4. Outflow at top of vortex, enhance by upper-air turbulense, shearing, divergence.

What three ways can air become saturated?

1. By adding water to the air 2. By mixing wet (usually warmer) air with drier (usually cooler) air 3. By lowering the temperature to the dew point

What are the four forces that determine wind?

1. Gravitational force 2. Pressure gradient 3. Coriolis Force 4. Friction Force=a drag that occurs as the wind moves across Earth's surface, without friction surface winds would move in paths parallel to isobars.

What are fronts?

A front is the leading edge of an advancing air mass. It is a place of atmospheric discontinuity, a narrow zone forming a line of conflict between two air masses of different temperature, pressure, humidity, wind direction/speed, and cloud development. Their rotation in the armosphere depends on Coriolis and shearing. -Shearing=when air streams are going in the opposite direction that causes turbulence. -Also depends on centrifugal force that reduces the pressure in the center of the front. This usually increases stability. If the air is drawn in it that is a least conditionaly unstable, it may rise--reducing low pressure further. --Fronts are boundaries between warmer and colder air masses. It requires: 1) warmer and colder air masses, 2) some motion that brings them into contact.

What is the oasis effect?

A large body of water takes a long time to evaporate water because of wind and moderately dry air. As small body of water will have a faster evaporation rate because it is surrounded by a dry surface and dry air.

What characterizes the monsoon system?

Between the Asian land mass and the Indian Ocean, there is unequal heating. During the northern hemisphere winter, an intense high pressure cell dominates the continental land mass. At the same time, the ITCZ is present over the central area of the Indian Ocean. The pressure gradient from Novemeber ot Match between land and water produces cold, dry winds that flow from the Asian interior over the Himalayas and southward across India. These winds dry out the landscape. During the Northern Hemisphere summer, the ITCZ shifts northward over Southern Asia and the Asian continental interior develops low pressure associated with high average temperatures. Meanwhile, subtropical high pressure dominates over the Indian Ocean, causing the warming of sea surface temperatures. Therefore, the pressure gradient is reversed from the winter pattern. As a result, hot subtropical air sweeps over the warm ocean toward India, producing extremely high evaporation rates. By the time it reaches India, this air is laden with moisture and clouds, which produce the monsoonal rains from about June to Septemer.

What are clouds?

Clouds are an aggregation of tiny moisture droplets and ice crystals that are suspended in air and are great enough in volume and concentration to be visible. o As an air parcel rises, it may cool to the dew point temperature and 100% relative humidity. More lifting of the air parcel cools it further, producing condensation of water vapor into water (with release of latent heat). Condensation requires cloud-condensation nuclei—microscopic particles that always are present in the atmosphere. Droplets remain suspended as long as small enough (not too heavy) o Cloud formation requires a cooling process, generally by adiabatic cooling of ascending air but sometimes by mixing warmer and cooler air masses. Cloud types and dynamics depend on atmospheric stability.

What are the two process in which precipitation forms?

Collision-Coalesence and the Bergeron Process precipiation forms around condensation nuclei

What is conduction?

Conduction is the molecule to molecule transfer of heat enerfy as it diffuses through a substance. As molecules warm, their vibration increases, causing collisions that produce motion in neighboring molucules, this transferring heat from warmer to cooler material. Heat is conducted from warming materials to cooler materials.

What happens to the temperature during the day?

During the day the surface is heated by incoming solar radiaiton. This in turn heats the atmosphere from the bottom up (it is heated by the surface). It is heated by H, sensible heat that is conducted upward. This follows the law that heat moves from warm places to cold places. At night this is reversed if the surface becomes cooler.

What happens to temperature during the night?

During the night, the surface cools, which in turn cools the atmosphere. This resuls in strong radiative cooling at the surface anc cold air drainage in hilly lofts. This also creates a temperature inversion.

What is earth radiation?

Earth radiation is the surface temperature only. It is represented by L arrow up.

What is electromagnetic radiation?

Electromagnetic radiation can be emitted, absorbed, or reflected (usually all three) by whatever it encounters. Since the Sun, atmosphere and earth's surface are the main objects involved. The main fluxes of radiation on the earth are solar radiation, reflected solar, earth radiation and sky radiation.

What is free convection?

Free convection is the ascent of warmer air, especially as a result of surface heating, that cools, causing condensation. This releases latent (i.e warms the air), causes instability, and ascends more. This circle can lift large amounts of air quickly. Also cools it quickly and makes large amounts of water available for precipitation.

What is the bergeron process?

Happens in cold clouds. Occurs when supercooled water and ice crystals coexist. Supercooled water (water that is below freezing point but is still water) has a higher SVC than ice, creating a pressure force to turn water into ice. This causes the ice crystals to grow in size at the expense of the liquid water, essentially producing snow. 1. water vapor is deposited on snowflakes faster than molecules can escape 2. with less water vapor in cloud, molecules can now escape faster from the water droplets 3. as water continues to evaporate from the droplets, more and more snowflakes are created.

What are isolines?

Isolines are the lines of constant value that connect points of equal temperature to protray the temperature pattern.

What is the intertropical convergence zone?

It is a band of clouds along the equator. Hadley cells begin with winds rising along the intertropical convergence zones. These winds move in opposite directions in each hemisphere.

What is the ITCZ or The Inter Tropical Convergence Zone?

It is a belt of low pressure which circles the Earth generally near the equator where the trade winds of the Northern and Southern Hemispheres come together. It is characterised by convective activity which generates often vigorous thunderstorms over large areas.

What is a squall line?

It is a line of thunderstorms ahead of a cold front along the outflow boundary

What is the environemental lapse rate (ELR)?

It is the cooling rate upward in the troposhpere.

What is the lake-snow effect?

Lake-effect snow is produced during cooler atmospheric conditions when a cold air mass moves across long expanses of warmer lake water, warming the lower layer of air which picks up water vapor from the lake, rises up through the colder air above, freezes and snow is deposited on the leeward (downwind) shores

What factors affect Coriolis?

Latitude, the speed of earth's rotation, the speed of the object (the faster the object is going, the greater it is deflected. The deflection will occur regardless of the object's direction and it will not impact the object's speed).

What happens if an air mass moves over a cool surface?

Movement over a cooler surface (usually mT or cT air masses) results in cooling the air mass from the bottom, this forming a temperature inversion near the surface. This makes the air mass stable. Warmer-> cooler surface->smaller ELR-> stability

What is net radiation?

Net radiation is the balance between incoming short-wave energy from the sun adn all outgoing radiation from Earth and the atmosphere. Is the energy inputs minus energy outputs. Earth loses more energy to space near the polar regions or areas of higher latitude. In these places the net radiation is negative. In lower atmosphere, this is offset by the flows of energy from tropical energy surpluses. Clear skies premit great longwave radiation losses from Earth's surface. Light colored surfaces also work together to reduce net radiation values. Latitudinal imbalance of energy drives global circulation in the atmosphere and oceans.

What is the ozone?

Ozone is made up of relatively reactive oxygen molecules that are made up of three oxygen atoms instead of the usual two atoms that make up oxygen gas. Ozone absorbs the shorter wavelengths of UV radiation. In the process, UV energy is converted to heat energy, safeguarding life on Earth by filtering some of the sun's harmful layers. It is found in the stratosphere in the Oxzone layer. For the past 35 years, there has been a creation of an ozone hole over the antarctic caused by ozone losses.

What is sky radiation?

Sky radiation is diffuse solar radiation that has been scattered by the atmosphere. It is represented by L up. The main controls are cloudiness, water vapor in air, effective sky temperature and pollution.

What is characteristic of soil?

Soil is often cooler, since incoming energy is absorbed quite near solid surface. So there would also be a flux of sensible heat from the warmer surface downward into the soil.

What is solar radiation?

Solar radiation is the shortwave radiation (represented by K down arrow) that reaches the earth's surface. Its main controls are latitude, time of year, time of day, elevation of sun, and cloudiness. It can be direct and difuse. These two things determines the intensity of radiation. If it is coming in a more direct, then the radiation is more intense. Since solar radiation is composed of shorter wavelengths, it is commonly called "shortwave" radiation (denoted by K) and earth radiation called longwave (denoted by L).

What is temperature?

Temperature is the measure of internal heat energy within a substance or object.

What is the earth's atmosphere and how does it change over the time?

The earth's atmosphre is composed of nitrogen, oxygen, argon, and carbon dioxide. It changes over time due to seasonality, natural exchanges of O2 and CO2 by photosynthesis, respiration, and decomposition. Long term change is due to the increase of carbon dioxide and other greenhouse gases from human activity,

How can air masses change?

The longer an air mass remains stationary over a region, the more definite its physical attributes become. As air masses migrate from source regions, their temperature and moisture characteristics slowly change to the characteristics of the land over which they pass.

What is temperature's daily cycle?

The maximum amount of input that will affect temperature is at solar noon. Warming continues as long as net gain continues. This stops when net gain and net loss are equal. High temperature are usually in the afternoon when energy loss by earth radiation (L arrow up) catches up with energy gained by the sun. The low temperature is usually around dawn, since earth continues to cool all night, until sunshine returns. High and low temperatures both usually occur later on a clouds day, since warming is slower.

What is the troposphere?

The troposphere is the final layer encountered by incoming solar radiation as it surges through the atmosphere to the surface. The marked warming with increasing altitude in the stratosphere above the troposphere causes the troposphere to act as a lid, that generally prevents whatever is in the cooler (denser) air below from mixing into the warm stratosphere (less dense). The troposhpere is heated by the earth's surface. The stratosphere is heated by the absorptionof sunlight by ozone (primarily UV absorption).

What is a pressure gradient?

The pressure gradient force drives air from areas of higher barometric pressure (more dense air) to areas of lower barometric pressure (less-dense air), thereby causing winds. A gradient is the rate of change in some property over distance. High and low pressure areas naturally exist in the atmosphere because areas are unequally distributed.

What is a vortex storm?

Vortex storms are naturally developing, self-maintaining air spirals around a rapid updraft, as in tornadoes and hurricanes. Rotation maintains low pressure inside the vortex (this is centrifugal force). Low pressure maintains the inflow of warm air (with latent heat to be released). The steep pressure from from outside to inside ensures rapid adiabatic cooling, which condenses water vapor, releases latent heat, and forms clouds, making the funnel visible. Updrafts create (or enhance) low pressure at the bottom (earth's surface). Rotation my be imparted by shearing aloft (causing cumulo-nimbus clouds to rotate), by feedback dynamics in the rising air column and coriolis (in hurricanes).

What are the westerlies?

Westerlies are the dominant winds flowing from the subtropics to higher latitudes. Surface air diverging within the subtropical high-pressure cells generates Earth's principle surface winds: trade wints and westerlies).

What is force convection?

When something forces air to rise, such as a mountain (orographic lifting) forcing air to rise around it. Frontal lifting is a from of forced convection by which moving air (pushed by a pressure gradient) is forced to override colder air (i.e to be lifted by a cold air wedge). Moving warmer air is pushed upward by colder air rising from the surface.

What is evaporation fog?

When water evaporates quickly but is then recondensed by the cooler air above. Example is sea smoke

What is a radiation fog?

fog that results from strong radiative cooling near the surface on a clear night. Is essentially cloud formation at the surface. when radiative cooling of a surface chills the air layer directly above that surface to the dew point temperature, creating saturated conditions, a radiation fog forms.

What are controls on temperature?

1. Clouds and Sky Conditions at night, clouds act as an insulating layer that reradiates longwave energy back to Earth, preventing rapid energy loss to space, in general the presence of clouds raises the minimum night temperature. During the day, clouds reflect insolation, lowering daily temperature maximums-shading effect. 2. Latitude--sun angle and path through atmosphere 3. Altitude--colder upward sinch atmosphere is heated from the bottom 4. Surface properties--land vs. water heating, contentinatal or coastal, windward or leeward side 5. Ocean currents--warm vs. cold currents 5. Local effects--albedo, wet vs dry

What are the stages of thunderstorm development?

1. Cumulus stage--rising air (the updrafts) cools and forms the cloud. 2. Mature stage--cloud continues to grow and precipitation particles form and fall from cloud. They fall into the updraft and drag air down with them. This sinking air is referred to as downdrafts. Entrainment (the dragging of air) into the downdraft causes it to be heaver and increases the downdraft. Rain begins to reach the surface. 3. Dissipating stage--when the downdrafts encompass the storm, the updrafts are shut off and the storm begins to die. The intensity of the rain decreases.

What is the lifecycle of a midlatitude cyclone?

1. cyclogensis--creation of a cyclone, usually beings along a polar front where cold and warm air masses converge and are drawn into conflict. The low pressure cell develops and creates a cyclic motion 2. Warm and cold fronts develop and the low pressure center deepend 3. We have a well developed cyclone which includes cumulus clouds and overcast stratus clouds in the cold fronts. The warm front feeds on instability. 4. Occlusion forms and there are large clouds amassing at the low pressure center. 5. Heavy rain occurs along the occlusion and the warm/cold fronts. There is also a cold north west wind behind the cold front. 6. occlusion is complete and the cyclone dissipates.

What are the requirements for precipitation?

1. water vapor in the air (humidity) 2. cooling below the dew point temperature, which results in cloud formation. Usually this is a result of a lifting process such as free convection or forced convection. 3. Enough liquid water that it becomes too heavy to remain suspended.

What is a cold front?

A cold front is the leading edge of a cold air mass. It occures when warmer air is being pushed up by cold air. Warm air on the bottom is trapped and creates an unstable atmosphere. Stronger instability occurs as cold air moves over warmer air and there is faster horizontal movement. CLOUDS PRESENT: CUMULONIMBUS-form and create thunderstorms/short, intense precipitation. As the cold air front passes, the cold air left over is colder and drier. The conditions change to rapidly clearing skies and windy as cold air continues to pour in. Are always unstable. After the front passes, the air is colder and drier, rapidly clearing skies, windy, and the cold or continues to pour in.

What is a mesoscale convectice system?

A mesoscale convective system is a complex of thunderstorms that becomes organized on a scale larger than the individual thunderstorms. Is composed of storm conditions over a large area. It includes an outflow boundary of downdrafts. It includes self-propogating storms in which downdrafts lift adjacent warm, wet air adn create new updraft cells nearby.

What is a pressure gradient?

A pressure gradient force drives air from areas of higher barometric pressuer (more dense air) to areas of low barometric pressure (less dense) air, thereby causing winds. A gradient is the rate of chane in some property or distance. High and low pressure areas exist naturally in the atmosphere because areas are unequally distributed.

What is a squall line?

A squall line is a narrow band of high winds and storms associated with a cold front. The line of thunderstorms ahead of a cold front.

What is a supercell?

A supercell is a thunderstorm with a deep, persistenly rotating updraft. They are the least common form of thunderstorm but potentially violent. It is smaller than a squall line and MCC. It rotates due to strong wind shear.

What is a temperature inversion?

A temperature inversion is the reversal of the normal upward temperature increase. Instead of getting colder as you go upward in the atmosphere, the temperature gets warmer. Temperature inversions always create stable situations.

What is a warm front?

A warm front is the leading edge of a warm air mass. Warm air is moving because of forced convection, overriding the cold air, which takes on a "wedge" shape. As the warm air is lifted, it cools adiabatically and clouds form--CLOUDS PRESENT ARE (IN ORDER) cirrus, altostratus, and stratus. Forced convection caused by a warmer air mass moving over a cooler air. It creates a cold air wedge that pushes warm air up. Stratus clouds begin to form. This is caused by a temperature inversion, which always creates a stable atmosphere. There is slow horizontal movement and slow patchy rain.

What is convection?

Conection is the transfer of heat by mixing or circulation. Movement of boiling water in the atmosphere or in bodies of water. Warmer (less dense) masses tend to rise, and cooler (denser) masses tend to sink. This physical mixing usually involves a strong vertical motion. When it's a horizonal motion it is called advection.

What is the hadley cell?

Constant high sun altitude and consistent day length make large amounts of energy available in the equatorial region. The warmong associated with this energy surplus creates a lighter, less dense, ascending air with surface winds converging along the entire extent of the low-pressure trough. This converging air is extremely moist and full of latent heat energy. As it rises, the air expands and cools producing condensation and heavy rainfall. This large convection event is known as a hadley cell. Within these cells, air moves northward and southward towards the subtropics, descending to the surface and returning to the intertropical convergence zone as the trade winds. These are greatest at equinox dates with the whole system shifting north and southward with the seasons.

What is a continentality?

Continentality refers to the continental effect-the greater range between maximum and minimum temperatures on both daily and a yearly basis that occur in areas that are inland from an ocean or distant from other large bodies. Continental areas have greater temperature ranges (higher highs and lower lows) and normal seasonal occurance.

What is dew point temperature?

Dew point temperature is the temperature at which a given sample of vapor containing air becomes saturated and net condensation begins to form water droplets. The air is saturated when the dew point temperature and the air temperature are the same. Saturation = 100% relative humidity. Dew point temperature depends on actual conditions, but is always lower (i.e cooling is required unless the air is allready saturated). Cooling beyond the dew-point temperature reduces SVC further and results in more condensation (while relative humidity remains at 100%). -a high dew point means there is a lot of water in the air. -Clouds form at the dew point temperature. -With no large gain or loss of water actually in the air (no storms or fronts), dew point temperature stays roughly the same over the course of the day and represents the base for estimating relaitve humidity over the day.

What is direct and diffuse radiation?

Direct radiation-travels in a straight line to Earth without being scatter or otherwise affected by materials in the atmosphere. Diffuse radiation- incoming energy that reaches Earth's surface after scattering occurs, is weaker, casts a shadow--less light onto the ground.

What is the collision and coalesence process?

Happens in warm clouds when falling water droplets form larger droplets (heavier fall faster and collide more).

What is a subtropical high?

It is high pressure areas sitauted around 30 degrees north and 30 degrees south. This is known as the subtropical high-pressure belts.

What is a polar front?

It is the area of contrast between cold air from higher latitudes and warm air from lower latitudes. Is the place where masses of air with different characteristics meet. This front encircles the earth, focused in low pressure areas. q

What is latent heat evaporation?

It is the enerfy stored in water vapor as water evaporates. Water absorbs large quantities of this latent heat as it changes state to water vapor, thereby removing this heat energy from the surface. Conversely, this heat energy releases to the environment when water vapor changes state back to a liquid. Latent heat transfer is the dominant expenditure of Earth's entire net radiation, especially over water surfaces.

What characterizes a land and sea breeze?

Land and sea breezes are local winds produced along coastlines. The differential surface heating between land and water surfaces create breezes. Land gains heat energy and warms faster than the water offshore. This air is less fense and begins to rise triggering an onshore coole marine air to replace the rising air. This flow is usually strongest in the afternoon forming a sea breeze. At night, the land cools faster than the water does. As a result the colder more dense air sinks and flows offshore toward the low pressure area over the warmer water where air was rising.

What happens if an air mass moves over a cool surface?

Movement over a warmer surface (usually mP or cP air masses) results in warming the air mass from the bottom, which increase the environmental lapse rate, perhaps enough to make the air in the air mass unstable. Colder air-> warmer surface-> larger ELR-> instability

Because of Coriolis, in what direction do objects seem to appear to move in?

Objects in the northern hemisphere seem to curve to the right. Objects in the southern hemisphere curve to the left. Coriolis deflection is zero at the equator and increaes toward the poles. Coriolis is thus weak in the tropics but significant in the middle and higher latitudes.

What is an oceanic gyre?

Oceanic circulations are known as gyres adn generally appear to be offset toward the western side of each basin. These systems are driven by the atmospheric circulation around subtropcial high-pressure cells. Ocean currents are created by global atmospheric circulation and move in the same directions. This results in gyres in each major ocean basin, with a warm current on the west side and a cold current on the east side of each basin.

What is insolation?

Once solar radiation enters the Earth's atmosphere it is scattered and absobed. The solar radiation that is intercepted by Earth is insolation. It specifically applies to radiation arricing at Earth's atmosphere and surface. Its amount is reduced by half or more through reflection, scattering, and absorption of shortwave radiation once it hits particles in the atmosphere. Insolation is distributed unevenly due to the curved surface of Earth adn difference in the angle at which solar rays meet the surface. Solar radiation is the single energy input that drives the Earth-atmosphere system. It is not equal at all surfaces across the globe. Greater insolation at the surface occurs in low latitude deserts worldwide because of frequently cloudless skies.

What are polar and monsoonal fronts?

Polar fronts occur between the westerlies and the erratic but often easterly winds in the polar regions--creates mid-latitude cyclones. Monsoonal fronts occur between wet oceanic and drier continental air.

What is radiation?

Radiation is the transfer of heat in electromagnetic waves, such as that from the Sun to the Earth or as that from a fire or burner on a stove. The temperature of the object or substance determines the wavelenghts of raditaion that it emits. The hotter the object, the shorter the wavelenght.

What are the forms of percipitation?

Rain, Drizzle (smaller drops than rain), Ice/Glaze (normal but cold rain that freezes upon contact with a cooler solid surface), snow, sleet, hail, virga (any precipitation that evaporates before reaching the ground, occurs in dry air usuallu in summer continental climates)

What is reflected solar radiation?

Reflect solar radiation is the radiation that comes from the sun and is then re-radiated by the earth's surface. Its main controls are surface albedo, surface roughness, and the angle of incidence. It is represented by the K arrow up.

What are self-extinguishing thunderstorms and self-propoagating thunderstorms? What are they classified as?

Self-extinguishing thunderstorms form within a single air mass and are not tied to fronts or mid-latitudes. Daily solar heating is primarily responsible for rising air motion that produces rising cumulus clouds. These storms may go through growing, mature and dissipation stages in just an hour or two. Are often associated with summer storms. Self-propogating thunderstorms accors along cold fronts. The front generates instability ahead of it that continues the conditions for storms to occur. Develop along fronts of two different air masses. This continues to generate areas of instability, perpetuating the storm. Classified as severe thunderstorms.

What are the main factors of surface heating and cooling?

Surface heating and cooling sets up a pressure gradient near the surface creating changes in pressure. If the surface heats up, it creates lighter air towards the surface. This air ascends, creating lower pressure at the surface. Surface heating drives local winds by creating horizontal pressure gradients. Surface hooling creates heavier air which causes the air to sink. This creates higher pressure at the surface. Surface heating and cooling can set the atmosphere in motion vertically and horizontally. Differential surface cooling occurs because land cools more and faster. Water cools slowly and only a small amount. This is because energy is distribued much deeper on land than water.

What is the coriolis effect?

The coriolis effect makes wind travelling in a straigh path appear to be deflected in relation to Earth's rotating surface. This force is an effect of the earth's rotation. On a non-rotating earth surface winds would move in a straight line from areas of high pressure to low pressure. On our planet, the coriolis force deflects anything that flies or flows across Earth's surface from a straight path. WInd appears to blow in arcs. Winds cross isobars at angles rathern than perpendicularly.

What is temperature's annual cycle?

The highest seasonal temperature is usually about 1 month after the summer solstice. The lowest seasonal temperature usually about 1 month after the winter solstice.

What are thunderstorms?

Thunderstorms occur when their is rapid, upward movement of warm, moist air. As the air rises, it cools and condenses to form clouds and precipitation. This process heats local air, causing violent updrafts and downdrafts as rising parcels of air pull surrounding air into a column and falling rain drops push air towards the surfce. The starting turbulence is created by mixing air of different densities or by the movement of air layers at different speeds and directions in the atmosphere.

What is saturation?

When the air is at 100% relative humidity. At saturation any further addition of water vapor or any decrease in temperature that reduces the evaporation rate results in active condensation.

What is evaporation?

When water changes from a liquid to a gas. Stores it as latent heat. It is mainly a function of two factors: energy input needed to change the state of water and dry unsaturated air that can take up more water.

What is a mid-latitude cyclone?

Where a cold front and a warm front meet around a low pressure center. Winds are moving counterclockwise around and into the center. The cold front moves faster than the warm front because the only obstacle to it is other cold air. The warm front moves slowly because it has to overcome the more dense cold air. Eventually the cold front catches up to the cold air infront of the warm front. This squeezes the warm air upward and creates an occluded front (when cold front overtakes a warm front creating a composite front) that moves slowly. At the cold front, the weather consists of rain, thunderstorms, and cumulonimbus clouds (the line with teeth). At the warm front depending on where the point of reference is, you would have first cirrus clouds, then altostratus, and then stratus which would have patchy rain. In the occluded front, we would have soaking rain.

What is wind?

Wind is the generally horizontal motion of air across Earth's surface. Differences in air pressure between one location and another produces wind. It moves along a pressure gradient (more dense air to low dense air) from high to low pressure. As air moves, whatever is in the air also moves, such as water vapor or clouds. Wind's two principal properties are speed and direction. Winds are named for the direction from which they originate. If there is high pressure, there is clear skies because clouds were driven away. Low pressure means there are cloudy skies because clouds are concentrated at the low.

What is relative humidity?

is the ratio of the amount of water vapor that is actually in the air compared to the maximum amount of water vapor that is possible in the air at a given temperature. It varies because of changes in water vapor and temperature. Warm temperature-evaporation rate is higher. Cooler air-condensation rate is higher. When evaporation and condensation are equal, saturation occurs.

What characterizes the maritime climate?

o Have reduced temperature ranges (less heating/cooling of air) o Later seasons (oceanic thermal inertia) o Marine effect= the moderating influences of the ocean and usually occurs in locations along coastlines and islands.

What is a jet stream?

o Irregular, concentrated bands of wind occurring at several different locations that influence weather systems. They tend to weaken during the hemisphere's summer time and strengthen during the winter as the streams shift closer to the equator. Jet streams define storm tracks.

What is an isobar?

o Is an isoline plotted on a weather map to connect points of equal pressure. The pattern of isobars provides a portrait of the pressure gradient between an area of high pressure and low pressure.

What is lightning and thunder?

o Lightning-flashes of light caused by enormous electrical discharges. A buildup of electrical energy polarity between areas within a cumulonimbus cloud or between the cloud and the ground creates lightning o Thunder-the violent expansion of this abruptly heated air sends shock waves in the form of a sonic bang.

What are mountain/valley winds?

o Mountain and Valley breezes are local winds resulting when mountain air cools rapidly at night and when valley air gains heat energy rapidly during the day. Valley slopes are heated sooner than valley floors. As a result, the slopes heat up and warm the air above, this warm, less-dense air rises and creates an area of low pressure. By the afternoon, winds blow out of the valley in an upslope direction along this slight pressure gradient, forming a valley breeze. At night, heat is lost from the slopes, and the cooler air then subsides downslope in a mountain breeze.

What are the equations for earth's net radiation?

o R= (k-arrow up - k arrow down) + (L arrow down - L arrow up) ♣ K down is always larger than k up, since reflection is always less than 100 percent ♣ L down is always smaller than L up, since the sky is cooler and less massive than earth ♣ R is always greater than zero during the day- this means there is a net input of energy and thus warming ♣ R is always less than zero at night (k down equals 0)-net loss of energy and thus cooling. o R= H+ G+ LE+ F+ Ph ♣ R= net radiation, the resultant sum of all the radiation processes K and L (positive input of energy during the day, net loss at night) ♣ H and G= Sensible heat conducted upward (H) or downward (G) during the day, following the law that heat moves from warmer (surface) to cooler places, at night this is reversed if the surface becomes cooler ♣ LE= represents the latent heat (energy) released by evaporation of water and transported upward by convection (generally zero at night) ♣ F= is net energy gain or loss by advection (horizontal energy transfer) • Usually assumed to be zero, what blows in one side blows out the other—wind ♣ Ph= the energy fixed into biomass by photosynthesis • Drives the biosphere, but very small

What are the Factors that can influence ELR and stability?

o Surface heating—surface air warmed and may rise o Surface cooling—surface air cooled, will not rise o Advection of warmer air—new air may be warmer than air above and could rise o Advection of cooler air—new air may destroy existing instability o Radiative cooling of cloud tops—creates larger ELR and can cause instability indirectly

What affects atmospheric stability?

o The stability of an air parcel depends on two temperatures: the temperature of the air parcel and the temperature of the air around it o Use a term called parcel to describe a body of air with specific temperature and humidity characteristics o Stability refers to the tendency of an air parcel either to remain in place or to change vertical position by ascending (rising) or descending (falling). An air parcel is stable if it resists displacement upward, or, when disturbed, tends to return to its starting place. An air parcel is unstable if it continues to rise until it reaches an altitude where the surrounding air has a density and temperature similar to its own. ♣ Air parcel warmer than air at target—air (atmosphere) is unstable, would rise to that level ♣ Air parcel cooler than air at target—air (atmosphere) is stable, no upward movement o The atmosphere is thus unstable if the ELR (environmental lapse rate) is greater than the adiabatic cooling rate (DALR if dry or WALR if saturated), as often is the case in the afternoon. ♣ If ELR is bigger than ten it is unstable, if it is less than ten it is stable.

What are trade winds?

o The winds converging at the equatorial low. Northeast trade winds blow in the northern hemisphere, and southeast trade winds in the Southern Hemisphere.

What is the greenhouse effect?

o When longwave radiation is absorbed by carbon dioxide, water vapor, methane, and nitrous oxide, chlorofluorocarbons and other gases in the lower atmosphere and then emitted back, or reradiated, toward Earth. Raises Earth's temperature. ♣ Like a greenhouse, this process allows shortwave radiation to come to earth, but does not let longwave radiation from leaving-sort of trapping it in the atmosphere—passage is delayed. o Re-radiation (L up) of absorbed solar radiation is the earth's only significant way to get rid of excess heat and maintain a stable temperature regime and stable energy balance (relative to space) o "Greenhouse Gases" such as CO2 and methane, however, absorb L up wavelengths but no K up or K down. Some of the energy absorbed may be eventually re-radiated upward, but most is retained in the earth-atmosphere system, causing Earth to heat up.

What is adiabatic cooling and warming?

♣ Rising air, encountering progressively less external pressure around it, can expand in volume (rising balloon) ♣ Sinking air, encountering progressively more external pressure around it, is compressed. ♣ The change in volume of the gas permits its energy to be "diluted" over a large volume or concentrated into a smaller volume. Less energy per unit=cooling, more energy per unit volume= heating ♣ Such processes occur without net gain or loss of actual energy (only its redistribution)—these are adiabatic processes • Rising air cools adiabatically—in fact at a constant rate of 10 degrees Celsius per 1000 m o Rises and hits the dew point temperature where water can condense and form clouds • Sinking air warms adiabatically—at the same constant rate o Results in drier air (lower relative humidity) with the evaporation of clouds and less chance of precipitation DALR if air is dry, WALR if air is wet

What are the four cases of stability?

♣ Stable •When the ELR is less than the DALR and the WALR. Temperature inversions are always stable, when cold air is beneath warm air ♣ Conditionally Stable ♣Neutral •When the ELR is between the DALR and WALR, ELR=DALR •Occurs briefly as atmosphere goes from unstable (daytime) to stable (night) and vice versa. ♣Unstable •When the ELR exceeds the DALR, when there is warm air is beneath cold air, produces clouds, Clouds form if unstable air rises far enough to cool below dew point temperature and cause condensation

What are the cloud types?

♣ Stratus—layered development in/below a stable atmosphere • Dull, gray, and featureless • Horizontal, layered development in a stable atmosphere. • Stability occurs at the surface and generally at least 2-3 km upward • Usually occur under cooler conditions or at least with a cooler surface, as at nighttime, over a snow cover, or with temperature inversion, are found in the middle of mid-latitude cyclones, in occluded fronts ♣ Fog—stratus cloud at the earth's surface ♣ Cumulus—vertical development in an unstable atmosphere • Bright and puffy • Usually occur in situations of surface heating, as by sunshine • Instability extends at least 2-3 km upward, often 10 km or more ♣ Cirrus—high remnants of other clouds (ice crystals) • Wispy clouds, can indicated an oncoming storm ♣ Nimbus—a rain producing cloud (of any type) o Cloud types by height ♣ High Clouds—ice crystals—cirrus ♣ Middle Clouds—mainly supercooled water, some snow/ice (winter) ♣ Low Clouds—liquid water droplets ♣ Clouds of vertical development—liquid water below to ice + supercooled water

Other characteristics of air masses

♣ Warm air holds more water, so warm air masses bring more precipitation. ♣ Precipitation decreases inland, since water is lost there is less remaining as an air mass moves inland. ♣ This means that windward coastal areas (including mountain slopes) are wetter (perhaps very wet) than areas further inland (including areas in the leeward side of mountains). ♣ Cold offshore ocean currents act to stabilize air masses, so coastal areas with cold currents offshore usually have very little rainfall.

What are the four main air mass characteristics?

♣ mP- maritime polar, occur over the pacific ocean (this dominates the northern US in the winter), also in the Atlantic (these may influence Europe more) ♣ mT- maritime tropical, occurs in the Gulf of Mexico, and also in the Pacific and Atlantic during the summer, dominates much of central and eastern US in Spring and Summer, precipitation increases with greater distance from the gulf ♣ cP- continental polar, occurs in central Canada, cold air sinks—causing a tongue shape or Siberian express, can cause a "polar outbreak" southward ♣ cT- occurs in southwestern deserts (small region, and only in summer), the thermal lows counteract the sinking effects of typical deserts, creates monsoon like conditions. In the southeast during winter, cP and mT affect the area.