Material Covered for Midterm 2
Material Covered for Midterm 2 Geog 1002
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This 16 page Study Guide was uploaded by Cj Sivulka on Friday March 25, 2016. The Study Guide belongs to Geog 1002 at 1 MDSS-SGSLM-Langley AFB Advanced Education in General Dentistry 12 Months taught by Dr Stereletskiy in Spring 2016. Since its upload, it has received 266 views. For similar materials see Intro to Physical Geography in Geography at 1 MDSS-SGSLM-Langley AFB Advanced Education in General Dentistry 12 Months.
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Date Created: 03/25/16
Chapter 6: Atmospheric Moisture Condensation – water vapor converted to a liquid; latent heat is released; atmosphere must be at saturation o Latent heat of condensation – heat released when water vapor condenses back to liquid form o Saturation the state of the atmosphere in which air contains the maximum amount of water vapor that it can hold at a specific temperature and air pressure; the relative humidity is 100 percent, temperature and dew point are equal, evaporation of water ceased o You need to have a surface for condensation to happen = condensation nuclei (dust, smoke, etc.) If there is none, then condensation won’t happen and the air will be supersaturated aka relative humidity over 100% o Supercooled droplets – when clouds have liquid droplets even when temperature is below freezing; promotes the growth of ice particles in clouds Global dimming – decrease in the amounts of solar radiation reaching the surface of the earth; some areoles (both anthropogenic and natural) may directly block sunlight, absorbing energy high in the atmosphere, and create more reflective clouds, all of which cool the surface and lower troposphere; this counteracts the actual effect of carbon emissions on global warming Temperature and Water in the Atmosphere: as temperature increases, water vapor capacity increases Clouds – visible collection of tiny water droplets and / or ice crystals suspended in the atmosphere; provide perceptible evidence of things happening in the atmosphere o Cloud Forms Cirriform clouds / cirrus – “a lock of hair;” highest clouds; thin and wispy and composed of ice crystals instead of water droplets; above 20,000 feet Cirrus; cirrocumulus; cirrostratus Stratiform clouds / stratus – “spread out;” middle clouds; appear as grayish sheets that cover most of or all the sky; layered; rarely broken up into cloud units; between 6,500 and 23,000; composed of water droplets and or ice crystals Altocumulus; altostratus Cumuliform clouds / cumulus – “mass clouds;” low clouds; massive and rounded, flat base, limited horizontal extent, billowing to great heights; below 6,500 feet; composed of mainly water droplets; heaped Stratus; stratocumulus; nimbostratus Vertical clouds –have bases as low as 1,000 feet and tops as high as 65,000 feet; composed of both water droplets and ice crystals cumulus; cumulonimbus Cloud formation – cooling air to the dew point; whenever air ascends or descents its temperature changes o Adiabatic warming – as air sinks and compresses, molecules become closer together and warm o Adiabatic cooling – as air rises and expands, molecules spread out and cool; the only way clouds / rain is formed Large masses of air can be cooled to the dew point only be expanding as they rise = how clouds and rain are created; a parcel of unsaturated air (RH less than 100%) moves upwards and expands and cools where RH will then be 100% Lifting condensation level – how high a parcel of air needs to be before the dew point is met and condensation can start happening; we see this when we see the “flat” bottoms of clouds” However, since condensation of water gives off latent heat; this heat counteracts the cooling and slows it a little; this diminished rate of cooling is called the saturated adiabatic rate Saturated adiabatic rate – the rate at which a saturated air parcel will cool or warm; depends on the amount of water vapor in an air parcel and the temperature o The Average SAR is 56 degrees Celsius per 1000 M Buoyancy of air – the tendency of an object to rise in a fluid under the influence of gravity; a parcel of air moves vertically until the surrounding air is of equal density (equilibrium level) o General rules: if an object is less dense then its surroundings then it will float; if it is denser then it will sink; if it is the same density then it will neither rise or sink o Air is stable if: Rising air is cooler than the surrounding air Resists vertical movement / being lifted upwards If it does move it moves only because a force is applied like being forced up a mountain Nonbuoyant Will not move without extra force o Air is unstable if: Rising air is warmer than surrounding air It moves via buoyancy Will rise with out external force or will continue to rise after moving that external force o Air is conditionally unstable when: When an air parcel’s adiabatic lapse rate is between wet and dry rates; it is the intermediate condition between stability and instability Atmospheric lifting: 4 types o Convective lifting – unequal heating of different air surface areas warming one parcel by conduction and not the air around it; spontaneous Air near the ground is heated and it rises; as it rises it cools and forms clouds; often results in rainfalls o Orographic lifting – occurs only when topographic barriers force air to descend upslope and cool to dew point Air is forced up a mountain slope and cools as air rises and rains only on that side of the mountain. This creates deserts in this area called the rain shadow area o Frontal lifting – when unlike air masses meet – air is cooled to the dew point because warmer air is forced to rise over the cooler air: creation of a discontinuous front A warm front and a cold front meet; the cold front pushes below the warm front so the air in the warm front is forced to rise; it rises and cools and rains = frontal precipitation o Convergent lifting – when air parcels converge and meet and the crowding forces uplift; happens in the ITCZ and tropical disturbances Two air parcels meet and the force pushes the air up; it cools and rains Precipitation o Formation Processes and mechanisms Collision / coalescence – responsible for precipitation in the tropics; rain is produced when water droplets collide and merge; there are no ice crystals; temp is too warm; the must keep coalescing until droplets are big enough to form and fall Condensation creates a large number of small droplets; when the large droplets fall faster they merge with smaller ones and keep falling Ice crystal formation – major cause for precipitation outside the tropics; ice crystals grow faster than the cloud water droplets; the air gets saturated more quickly by ice crystals than by liquid droplets because crystals are colder and this have a lower saturated vapor pressure o Forms of precipitation Rain – most common and wide spread; drops of liquid water; result of condensations thawing of ice crystals Snow – solid precipitation in the farm of ice crystals, small pellets, or flakes; formed by direct conversion of water vapor to ice Sleet – small rain drops freezing during descent; reach ground as small pellets of ice Glaze or freezing rain – rain that turns to ice the instant it collides with a solid object Hail – rounded or irregular pellets or lumps of ice produced in cumulonimbus clouds as a result of active turbulence and vertical air currents; small ice particles grow by collecting moisture from super cooled cloud droplets o Spatial distribution of precipitation A very important aspect of atmospheric moisture; its uneven on earth but there are patterns observed Isohyet – a line joining points of equal quantities of precipitation Wet areas – warm places; mountain areas, edges of continents, placing with rising air, costal regions, tropical latitudes, narrow zones along the western coasts of North and South America Chapter 7: Atmospheric Flows and Disturbances Air masses – contain uniform temperature and humidity characteristics; have uniformity; must be large; must have uniform properties in the horizontal dimension; must travel as a unit o Formation: An air mass develops when it stagnates or remains over a uniform land or sea surface long enough to acquire the temperature / humidity / stability characteristics of the surface below Source regions – regions of earths surface that are particularly well suited to generate air masses; uniform areas; extensive, physically uniform Moisture content can be classified by maritime (wet) or continental (dry) Temperature can be tropical, polar, or artic Fronts – boundaries between unlike air masses; the transition zone between two air masses of different temperature and moisture content (their densities are different) o Locating fronts: Sharp temperature changes Sharp dew point changes Wind shifts Pressure changes The pressure of clouds and precipitation o Types of fronts Cold front – lower portion of a cold air mass is slowed relative to the upper portion; clouds of vertical movement; short duration, intense precipitation, rapid lifting and adiabatic cooling of the warm air ahead of a cold front Warm front – stratiform clouds; long duration, precipitation usually occurs slowly; gentle frontal slope; during summer can get storms also; clouds form slowly, limited turbulence; Stationary front – when neither air mass displaces the other, or if a cold front or a warm front “stalls;” cloud types depend on the atmospheric stability; precipitation intensity depends on the situation; Occluded front – formed when a cold front overtakes a warm front; shown by a combination of warm and cold front symbols; clouds and precipitation depend on atmospheric stability Atmospheric Disturbances = storms, or abnormal calm clear weather o Characteristics of atmospheric disturbances: Smaller components of the general circulation, although they are extremely variable in size They are migratory They have relatively brief duration, persisting for only a few minutes, hours or days They produce characteristics and relatively predictable weather conditions o Major disturbances – happens mid latitude where the major disturbances occur Multitude cyclones – responsible for day to day weather changes; moves the westerlies; occur between 30 and 70 latitudes; migratory low pressure system Very large systems; 1600KM diameter; highly variable; starts along the polar front; cold air of the polar easterlies meets the westerlies; vast cell of low pressure; when the two air masses meet a front develops and a wave between the air masses form due to differences in pressure; the pressure differences result in rotation so a cyclonic circulation is established; eventually the cold mass overlaps the warm one and occlusion begins; as the two air masses mix, the cyclone dissipates Anticyclones – high pressure cell of the mid latitude; moves west to east with the westerlies Hurricanes – low pressure centers that are circular with a steep pressure gradient outward from the center; strong winds spiral inward o Minor disturbances Thunderstorms – a violent convective storm accompanied by thunder and lightening which is usually localized and short lived; normal clouds produced by thermal convection Tornadoes – intense vortex; deep low pressure cell surrounded by a violently whirling cylinder of wind o Distribution of cyclones and anticyclones – at the midlatitudes; they alternate with one another in regular sequence around the world in the midlatitludes; they each occur independently of the other; an anticyclone usually follows a cyclone o Storm tracks in north America – travel from west to east in the northern hemisphere; Shift north in the summer and south in the winter Tropical Disturbances: Easterly Waves and Hurricanes o Tropical weather – between 23.5 degrees N and S of the equator; solar radiation does not vary much from season to season (generally NE, E, SE (easterly trades) tend to be quite weak; thunderstorms and tropical depressions/storms and hurricanes are found in the tropic o Easterly waves – long but migratory, low pressure system that may occur almost anywhere between 5 degrees and 30 of latitude migratory; long and weak; low pressure system bands of small thunderstorms; in tropics (5 degrees to 30); sometimes intensify into Hurricanes The trough axis marks where the trades are converging with rising motion behind the moving wave, and where divergence and sinking motion occur ahead of the wave axis o Development of a storm 1. Surface air that spirals into the center of a low pressure system creates convergence Forces air to rise in the center Air cools and moisture condenses which releases latent heat into the air 2. Warm air is less dense than cooler air Expansion of warm air forces more air outside away from the center of the storm and the surface pressure decreases 3. When the surface pressure decreases, a larger pressure gradient is formed, and more air converges towards the center of the storm. Creates more surface convergence and causes more warm moist surface air to rise above the surface. This air, as it cools, condenses into clouds. While it does this, it releases even more latent heat. 4. Enhanced convection back to 2. o Stages of development / categories of tropical disturbances – the three categories of tropical disturbances are based on wind speed Tropical Depression – winds near the center are constantly between 20 and 33 knots Tropical storm – wind intensifies; between 3546 knots; tropical storm; assigned a name Hurricane – surface pressures continue to drop; sustained wind speeds reach 64 knots; pronounced rotation develops around the central core o In a hurricane At low levels, air flows cyclonically into the center of the storm Diverging, anticyclone motion at tropopause level Rising motion occurs in the eyewall, thunderstorms adjacent to the eye Subsidence on outer edge of storm Rain bands; all air is moist Sinking motion in the eye o What you need for hurricane formation: Warm sea surface temps – greater than 26.5 C Ocean depth of 50M or more light winds throughout the troposphere you need convergence and a trigger weak frontal boundary happens near the ITCZ (but not on the equator) and the easterly waves o Hurricane destruction and fatalities Wind, heavy rain, tornadoes, storm surge (When wind driven waves produce storm surges of water on the coast; rise in water level associated with pressure drop); When hurricanes reach landfall the dissipate; but remnants may still cause destruction, especially when merging with a mid latitude cyclone o SaffirSimpson Scale – ranks the intensity of hurricanes; based primarily on wind speed ranging from 15 with 5 being the worst severe Thunderstorms: o A violent convective storm accompanied by thunder and lightening, is usually localized and short lived; associated with mid latitude cyclones, localized convection, orographic lifting and tropical cyclones; vertical air motion, considerable humidity and instability (unstable uplift); cumulonimbus cloud and showery precipitation; found in conjunction with other storms like hurricanes, tornadoes and fronts o Formation: Cumulus stage Uplift of warm and moist air which releases latent heat of condensation to sustain the continued rise of air; updrafts prevail and clouds grow Mature stage Above the freezing level, super cooled water droplets and ice crystals coalesce; they become too large and fall; when they fall they drag air down with them which causes a downdraft; Unstable and encouraged by diverging air aloft Dissipating stage – the downfalls dominate and cause light rain ending and turbulence ceasing Common where there are high temperatures, high humidity and high instability (like by the ITCZ) o Geography of thunder storms – frequency decreases with distance from the equator; few above 60 degrees north and south; most occur during summers warm temperatures o Violent associations with thunderstorms: hail, downbursts, lightening and thunder; tornadoes o Lightening – discharge of electricity that occurs in mature thunderstorms; charge separation in cloud sets up electrical potential; lightening equalizes these differences in electrical potential o Thunder – air is a poor conductor of electricity so huge electrical potential develops; a lightening bolt super heats the air so the surrounding air expands violently which makes a sound wave; for each 5 seconds between thunder and lightening, the storm is 1 mile away o Tornadoes – intense vortex; localized; cyclonic low pressure cells; surrounded by a whirling cylinder of wind violently; have the most extreme pressure gradients; usually in warm moist unstable air masses in mid latitude cyclone – cold front Formed by: 1% of thunderstorms; strong updrafts; wind shear (change in direction of strength of winds from top to bottom of storm); formed in moist warm unstable air; virtually all tornadoes are generated by severe thunderstorms V a funnel cloud – a violent, whirling, funnel shaped cloud that does NOT touch the ground A lot of tornadoes in the Midwest but happen in every state in the US; notable increase in tornadoes over time; population / technology induced observation bias (but still – does this have to do with climate change?) Enhanced Fujita Scale – describes strength of tornado based on estimates of 3 second gust wind speeds as determined by observed damage after a tornado o Waterspout – tornado over water; less power; smaller temperature gradient; gentler winds; reduced destructive capability Chapter 8: Climate Zones and Types o Temperature and precipitation are the most significant and understandable features when classifying climate o General bands of latitude o Low – between equator and 30N and S o Midlatitude – between 30 and 60 N and S o High latitude – greater than 60 N and S o Equatorial – within a few degrees of the equator o Tropical – within the tropics o Subtropical – slightly poleward of the tropics 2530 N and S o Polar – within a few degrees of the poles o Early classification schemes – generalized a vast array of data in a simple form; it was away to compare and contrast different areas o Ancient Greek scheme Had 5 zones, one torrid (tropics); two temperate (mid latitudes), 2 frigid (polar) o Koppen System Tropical humid (equatorial) Zone A Dry (Deserts) Zone B Mild Midlatitude (mild winter) Zone C Severe Midlatitude (boreal, cold winter) Zone D Polar (always cold) Zone E Highland (mountains, plateaus) Zone H o Modified Koppen System First letter is the climate group (temperature) A – Tropical humid; low latitude; warm and wet; cover most of the land area within 1520 degrees of the equator; lacks cold weather B – dry; evaporation exceeds precipitation C – mild midlatitude; mild winters, warm or hot summers D – severe midlatitude; sever cold winters E – Polar; very high latitude, cold climates H – highland; high mountains; elevation is dominant control Second letter precipitation For A, C, D Climate precipitation o F = wet all year; o M = monsoonal precipitation (very wet summers) o W = winter dry season o S = Summer dry season For B Climate precipitation o W = desert o S = steppe E Climate precipitation o T = tundra o F = ice cap Third letter temperature patterns C and D climate temperatures o A = hot summers o B = warm summers o C = cool summers o D = very cold winters B climate temperature o H = hot desert or steppe o K = cold desert or steppe 5 Major climate groups: ABCDE; 14 individual climate types; special category of highland H climate o A climograph = shows average monthly temperature and precipitation in a given area o Characteristics of the Zones Zone A = tropical Humid climates; low latitude; warm and wet; cover most of the land area within 1520 degrees of the equator; lacks cold weather AF – tropical wet; seasonless, similar weather all the time, uniform insolation all the time Am – tropical monsoon; similar to tropical wet but has heavy rainfall and slightly lower temperatures in the summer than in the spring Aw – tropical savannah; most extensive of A types; lesser annual rainfall; wildfires in dry season; low sun in dry season Zone B = really dry; 30% of all land area on the earth (a lot, more than any other climatic zone); influenced by subtropical highs (HIGH and DRY! These are the areas of high pressure along the midlatitude region that cause dryness and warm weather) Subtropical Desert (BWh) – either in or near subtropical highs; very low rain; hot temperatures; rain is scarce, unreliable and intense; large ranges of temperature Subtropical Steppe (BSh) – around subtropical deserts; have similar temperature and precipitation but not as extreme Midlatitude Desert (BWk) – extremely arid; occur in the interior of continents; have cold winters Midlatitude Steppe (BSk) – semi arid; transition zone between midlatitude desert and humid climate Zone C = mild mid latitude climates; equatorward margin of middle latitudes; long and hot summers and short and relatively mild winters Mediterranean (Csb) – western side of continents; winter wet and mild because of westerlies; the summers are dry and have clear skies in the southern hemisphere) Humid Subtropical (Cfa, Cwa, Cwb) – eastern side of continents; 2530 degrees in latitude; summer is hot and humid and has the most precipitation; the winter is mild but there is no real dry period Marine West Coast (Cfb, Cfc) – occur about 40 degrees and 65 degrees in latitude on the western side of continents; affected by westerlies and moderating ocean affects from these winds Zone D = Severe Midlatitude Climates – continentally only in the northern hemisphere; four seasons with long cold winters; moderate precipitation Humid continental (Dfa, Dfb, Dwa, Dwb) – between 35 and 55 degrees in north America; extends to 60 degrees in Europe; westerlies and snow precipitation in winter; summer has convective precipitation (unequal heating of different air surface areas warming one parcel by conduction and not the air around it; spontaneous; results in thunderstorms) Subarctic (Dfc, Dfd, Dwc, Dwd) – long, dark, bitter, cold winters; summers can be warm; in the continents (not that close to sea); 5070 degrees; Alaska to eastern Canada, Scandinavia to easternmost Siberia Zone E = polar climates; Tundra (ET) has low precipitation, cold; extremely short growing season; low primary production; there’s a treeline (an edge of a habitat in which trees are capable of growing); low primary production Ice Cap (EF) – almost no precipitation; extremely cold; ice dominates; no vegetation Zone H = Highland; variable over short distances; altitude matters not latitude (mountains); steepness; exposure and local circulation affects these regions Chapter 8: Climate Change What is Climate Change? o A significant shift in the mean state and event frequency of the atmosphere; despite negative connotations, it’s a normal component of Earth’s natural variability; occurs on all time and space scales Climate Forcings o The changes that affect the energy balance of the planet: Fluctuations in the earth’s orbit Fluctuations in the sun energy output Variations in ocean circulation Changes in the composition of the Earth’s atmosphere Changes in the Earth’s surface (The most significant changes occur when the global energy balance between incoming energy from the sun and outgoing heat from the Earth is upset) Measuring climate change o Modern Using satellite temperature measurements; these have been obtained from the troposphere since 1987; though this time isn’t long relative to the longevity of Earth’s existence, it shows a steady increase in temperature since this year th Surface air temperature records extend back to the middle part of the 19 century; the oldest record comes from central England and is 300 years in length o Other methods Historical documents Proxy methods (oxygen isotope analysis from ice cores; pollen in sediments; plants and animals) Geologic evidence Paleoclimatology – the study of Earth’s climate through the course of geologic time o Glacial Cycles – the concept of a glacial age with widespread effects was first proposed in 1837 by Louis Agassiz (Swiss scientist) Using Proxy Data (one thing in place of another) o Ice cores, tree rings, pollen, cave sediments and corals, insects, microorganisms o Ice cores and sediment Looking at volcanic ash in the ice as well as particulates such as dust, pollen; chemical composition of the air trapped inside the ice; etc We can also do something called Oxygen Isotope Analysis Measuring the ratio of 16O to 18O; this tells us about the environment in which these molecules formed; they evaporate at different rates so their ratio says a lot about the climate conditions Measuring using the deuterium / hydrogen ratio Measuring the ratio of 2H to 1H Deuterium is heavier than normal Hydrogen so it takes more energy to evaporate any water molecule made with this heavy hydrogen So the colder it gets, the less deuterium ends up in precipitation The smaller the Deuterium to Hydrogen ratio, the colder the climate o Volcanic ash layers – a source of a chemical signature; provides a calibration layer across variety of deposits o Tree Rings – each documents the year because they have annual layers of growth o Remant Landforms – sand wedge cast; seeing what’s embedded in sand / sedimentary rock o Deep Ocean drilling – we can also drill into the ocean floor and look at sea floor sediments; Varves are annual layers of sediment deposits (like tree rings!) Natural causes of climate change o Plate Tectonics – the breakup of Pangea created increased volcanic activity; this caused large scale degassing and a release of CO2 from the earth into the air o Volcanism –releases ash and CO2 into the air; ash creates a cooling effect because it prevents heat via sun from entering into our atmosphere o Changes in position of continents and ocean circulation – disruption of the normal ocean circulation could cause rapid climate change due to changes in the distribution of heat across the planet o Milakovitch Cycles – This guy was a Serbian mathematician; he calculated changes in insolation due to changes in orbital characteristics, mainly by impacting seasonality; he looked at variations in Earth’s orbiteccentricity (the earths path around the sun), changes in the earth’s tilt, and changes in the direction of axis points (called precession); many scientists don’t believe him but Earthsun relations do have an impact on glacial and interglacial events There has been ~ 18 glaciations in the past 1.8 million years (glaciation is the process of land being covered by glaciers due to cooling trends) Last glaciation was abut 1821 thousand years ago; ended about 10 thousand years ago Results: world sea level fell about 120m, thereby causing large expanses of the shallow continental shelves to emerge as dry land; disruption of major stream systems; Missouri and Ohio rivers move into new courses beyond the ice margin; disruption of thermohaline circulation (the currents were disrupted) o Sun Spots – fluctuations in solar output; sun spots are huge magnetic storms and they occur on an 11 year cycle; they are known to cause problems with satellites Paleoclimatology History o The Younger Dryas is one of the most wellknown examples of abrupt change due to a disrupt in thermohaline circulation. The trigger was the freshwater influx to N Atlantic associated with glacial melting. About 14,500 years ago, the Earth's climate began to shift from a cold glacial world to a warmer interglacial state. Partway through this transition, temperatures in the Northern Hemisphere suddenly returned to nearglacial conditions o Medieval Warm Period: – ~7001000 A.D. –Caused b expansion of crops in Europe and Viking exploration = sea ice retreat and colonization of Greenland o Little Ice Age: – ~1200, 1500 & 1800 A.D. – Glaciers grow in Europe = Crop failure Human Impact on Global Climate change o Today: The volume of CO2 has increased by about 38% in the last three hundred years. This increase is primarily due to human induced burning of fossil fuels, deforestation, and other forms of landuse change. Prior to 1700, levels of carbon dioxide were about 280 ppm (parts per million). Concentrations of carbon dioxide in the atmosphere are now a little over 400 ppm o Most of our energy comes from fossil fuels; not enough from solar and water o Global climate model mploys a mathematical model of the general circulation of a planetary atmosphere or ocean. It uses the Navier–Stokes equations on a rotating sphere with thermodynamic terms for various energy sources (radiation, latent heat). These equations are the basis for computer programs used to simulate the Earth's atmosphere or oceans. BASICALLY, technology to model the global climate for weather predicting and climate change. o Sea levels are expect to rise at this rate of CO2 emissions. Humans suck. Sea ice retreat / melting (can cause a disrupt in the thermohaline circulation = we are heading into something very dangerous) Ch 9: The Hydrosphere Hydrosphere o Describes the waters of the Earth Water exists on the earth in stores: atmosphere, oceans, lakes, rivers, soils, glaciers, and groundwater Water moves from one store to another through: evaporation, condensation, runoff, precipitation, infiltration, and groundwater flow o Hydrological cycle endless circle of water from atmosphere to earth and its return to the atmosphere through condensation, precipitation, evaporation, transpiration; continuous o Earth Moisture inventory 97.2% of all water is ocean 2.15% Ice sheets and glaciers 0.63% ground water 0.02% other (stream channels, atmosphere, soil water, fresh water lakes) Less than 1% of earth's moisture is actively moving in the hydrological cycle o Residence time of a reservoir the average time a water molecule will spend in that reservoir; a measure of the average age of the water in that reservoir Atmosphere is 9 days Ocean is 3,2000 years o Oceans are actually just one huge ocean broken down into 4 major ones: Pacific, Atlantic, Indian, Arctic o Characteristics of Ocean Waters Chemical composition: all elements but mostly chlorides, sulfates, carbonates, sodium, potassium; creates an Alkaline (basic) environment for the ocean Salinity distribution: average 35 parts per thousand Temperature distribution: 2 to 26 degrees C Water density: (similar to air!) high temp > low density Low temp > high density High salinity > high density Low salinity > low density Thermohaline circulation happens as a result in different temperatures and densities Acidification lowering of pH to be more acidic; ocean is basic so this is bad; happens when CO +2H O 2> H CO 2car3 nic acid); happens when there's too much CO2 in the air; hurts the sea environment especially corals Surface Currents – caused by wind flow; (other currents are caused by temperature and salinity) Deep Ocean currents – caused by differences in water density that arise because of salinity and temperature; referred to as thermohaline circulation Ice The Cyrosphere o Second only to oceans as a place to store water Land ice ice sheets, ice caps, alpine glaciers, = 10% of the land surface Oceanic ice Ice pack an extensive and cohesive mass of floating ice Earth's largest ice pack is in the Arctic ocean Ice shelf a massive portion of a continental ice sheet that projects out over the sea Ice floe a large flattish mass of ice that breaks off from large ice bodies and floats independently Iceberg a chunk of floating ice that breaks off from an ice shelf or glacier o Climatic Snow line the altitude at which glaciers can exist o Sea Ice extent – more in winter; but less over the past years b/c global warming o Land Ice / Glacial ice – all of Antarctica; Greenland; o Snow extent in northern hemisphere from the poles to about the middle of the states o Permafrost – ice that occurs beneath the land surface; permanently frozen soil; Canada, Alaska, Siberia; global warming is causing a lot of this to thaw disrupting pipelines, buildings, cities, etc Surface water – limited amounts; 0.025% of the world’s total water; variable in space; used for drinking and agriculture o Lake – a body of water surrounded by land; natural basin having a restricted outlet; sufficient inflow of water to keep basin filled; contain 90% of non frozen surface water; some are fresh water some are salt Formation of lakes natural basin with restricted outlet; sufficient inflow of water; glaciation, faulting, volcanism, karst Reservoirs – artificial lakes; made for human use; usually created by dams o Swamps – a body of water with water tolerant plants, predominantly trees o Marsh – a body of water with water tolerant plants; primarily grasses and sedges o Rivers and streams – a natural watercourse flowing towards an ocean or other body of water o Drainage basin – watershed; where all the water / rain fall of an area flow to one single point; Mississippi river in US is largest one; all water flows into that river and into that ocean; all of the land areas drained by a river and its tributaries o Ground water – water stored underground; 2.5 times the amount found in lakes and streams; found in many places but you just need to dig; no evaporation and can last a long time Water movement and storage o Porosity – the percentage of total volume of material that consists of voids (pore spaces or cracks) that can fill with water; the more porous a material is, the more it can hold water o Permeability – the ability of a material to transmit ground water; water moves by twisting and turning through small interconnected opening o Infiltration capacity o Aquifers – porous rocks saturated with groundwater o Aquicludes – impermeable materials/rocks; wont let water get through; prevents water movement Hydrologic zones o Saturated zone – subsurface of zone where all pores of the ground are filled with water o Ground water – water occupying the saturation zone and moving under the force of gravity o Water table – the boundary between the unsaturated zone containing soil water and the saturation zone which holds the ground water Water table is highest under hills (seepage into streams, lakes and marshes lowers it in valleys and other topographic depressions) o Ground water is recharged by percolation of water from the soil water belt downward to the zone of saturation. It is discharged by seepage into streams, lakes and marshes and other topographic depressions Ground water is always moving by force of gravity from recharge areas to discharge areas Unconfined flow – water can go anywhere Confined flow – the ground / dirt keeps the water going in one direction A confined aquifer creates an artisan well Ground water mining – removal of water from an aquifer at a rate greater than its flow and recharge capacities; this results in collapsing aquifers (because water in aquifers provide support for porous rock) = decreased capacity for aquifers to hold water (cuz they’re collapsed) and land above gets messed up too Ground water mining can also result in salt water intrusion – contamination of an aquifer by seawater due to over pumping the aquifer Cone depression – when water is taken from a well faster than it can flow in from surrounding saturated rock = the water table drops and creates an inverted cone The Ogallala Aquifer Largest Aquifer in the United states; 225,000 square miles; Accumulating water for 30,000 years; Water about the size of a larger Great Lake; Only moderate precipitation today; Affected by heavy groundwater mining over the past 100 years, the last 50 especially; when this runs out the mid west is in big trouble because they get their water for agriculture from this guy! water table has dropped more than 40 feet in places – if mining stopped, it would take 1000 years to recharge – water used to irrigate grain crops (wheat, sorghum and corn, providing 40% of cattle feed) and cotton – the City of San Antonio, TX depends entirely on water from the Ogallala aquifer – Underground water does not obey property rights Chapter 11: Cycles and Patterns in the Biosphere Biosphere consists of all living things, plant and animal; processes and interactions within the biosphere are exceedingly intricate energy, water and nutrients Biogeochemical cycles o The flow of enerfy o The hydrologic cycle o The carbon cycle o The oxygen cycle o The nitrogen cycle The Flow of Energy sun is the basic source of energy o Photosynthesis the production of organic matter by chlorophyll containing plants and animals; energy is fixed or made stable by plants (Chemical Energy); builds stored chemical energy in a plant; only happens during the day Only about 1 percent of solar radiation reaching a plant is used in photosynthesis Rate of photosynthesis is dependent on several things, especially the amount of light received ... up to a point. As solar radiation increases the rate of photosynthesis increases. •As incident solar radiation increases the rate of photosynthesis levels off, or may decrease. Plant becomes too hot and the need to cool the plant increases As a result, transpiration takes over as the dominate plant process Transpiration, the loss of water from plants, acts to cool the plant by releasing latent energy. o Respiration (reversed process of photosynthesis); when plants break up those simple sugars and oxidize them; the process of oxidation of carbohydrates leading to the release of energy; process of burring stored chemical energy basically though oxidation, for maintaining plant metabolism; can go on all the time o NPP net primary productivity; plant growth depends on a surplus of carbohydrate production; the difference between photosynthesis and respiration; high NPP means that plants are healthy and they accumulate a lot of energy to be stored; higher near the equator and warm regions because lots of sun and rain and good growing conditions; desert area really low NPP; o Hydrologic cycle most abundant single substance in the biosphere is water; medium of life processes; source of their hydrogen; watery solutions dissolve nutrients and carry them to all parts of the organism; it can bind to plant and animal tissues; source of all reactions; o Carbon cycle one of the basic elements of life; almost all life forms are carbon based; it is in a continuous state of creation, transformation and decomposition; photosynthsis assimilates atmospheric carbon into the biosphere; respiration returns carbon as CO2; carbon moves constantly from the living system to organic reservoirs and back o Oxygen cycle Oxygen is mainly a byproduct of photosynthesis; we pretty much know what happens with oxygen (breathing, repirating, etc) o Nitrogen cycle atmosphere is 78% nitrogen; soil bacteria and cyanobacteria; Nitrogen fixation conversion of the gaseous form to nitrates (usable by plants ) Primarily fixed by soil microorganisms and plants Secondarily fixed by lightening and cosmic radiation; marine organisms Humans cause nitrogen fixation by the manufacture of nitrogenous fertilizers; nitrogen fixing crops such as alfalfa, clover and soybeans o Food Chains pathways of energy, water, and nutrients on which organisms depend for their survival Plants are autotrophs (they are self feeders by getting energy from the sun; storing solar energy) Animals are heterotrophs they consume the plants Primary consumers are herbivores, they eat the plants Secondary consumers are carnivores they eat the primary consumers (meateaters) o Food pyramid energy transfer from large number of lower forms of life through smaller number of higher life forms o Biomagnification increasing concentration of a substance such as a toxic chemical, in the tissues of organisms at successively higher levels in a food chain o Biological factors and natural distributions evolution, migration, reproduction, mass extinctions, succession; o Environmental relationships the influence of climate (light moisture, temperature, wind); edaphic influences (soil characteristics); topographic influences; wildlife o Environmental Adaptations 1. Xerophytes – a type of plant that adapted; has modified roots; stems are spongy so they store moisture; leaves were modified; can reproduce 2. Hydrophytes – extensive roots; pliable stems; o Ecosystem: Totality of interactions among organisms and the environment in any area Applied at many scales o Biome: large, recognizable assemblage of plants & animals in functional interaction with its environment o Ecotone—the transition zone between biotic communities in which the typical species of one community intermingle with those of another. Useful for world distribution patterns Described by their dominant veg. type Spatial Groupings of Plants o Vegetation Associations – Emphasis is usually based on the structure and appearance of the dominant plants 1. Forests – Trees growing close together 2. Woodlands – Tree dominated – spaced apart 3. Shrublands – Short woody plants 4. Grasslands 5. Deserts 6. Tundra 7. Wetlands o Plants grouped by: Local conditions Vertical zonation – horizontal layering of different plants on a mountainside or hill side (changes with altitude) Varying local environmental conditions Exposure to sunlight Adret Slope: Direct angle of sun’s rays Ubac Slope: Low angle, less heating and evaporation Valley bottom lovations Riparian vegetation – plants that grow long the side of a river or lake o Vegetation in major biomes Tropical Rainforests (A/Af) – high temp; high humidity; broadleaf evergreen forest with numerous tree species; continuous canopy of trees with multiple layers; forest floor is clear because sunlight can’t reach it Mediterranean Woodland Shrub (Csa) – winter wet, summer dry and hot; biome is dominated by woody shrubs; Chaparral in NA; Sclerophyllous plants which are adapted to dry weather; many species survive via fire (some plants have adapted to NEED fire in order to open their seeds to grow – produces regeneration) Boreal Forests (Tiaga) – one of the largest biomes, covers much of northern North America and Eurasia; limited number of species; trees primarily needle leaf; evergreen conifers; southern areas very close together; further north they are more spread out with more shrubs in between; trees tip due to permafrost Midlatitude Deciduous forests – extensive areas on all northern Hemisphere continents (C and D climates); much has been cleared for agriculture and other human use; fairly dense growth of all broadleaf trees that provide a complete canopy cover in the summer; nearly closed canopy; relatively barren undergrowth; dramatic change between winter and summer; Tundra (ET) – treeless; cold desert / grassland; permafrost
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