Weather, climate, and Ecosystem.pptx

7/25/2019 Weather, climate, and Ecosystem.pptx

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Weather,climate, andEcosystem


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Weather


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Weather, state of the atmosphere at a particular place duringa short period of time.

Involves such atmospheric phenomenaas temperature, humidity, precipitation (type and amount), airpressure, wind, and cloud cover.

Weather, as most commonly dened, occurs in thetroposphere, the lowest region of the atmosphere thatextends from the Earths surface to !"# $m (%"& miles) at thepoles and to a'out $m ( miles) at the E*uator.

+ecent research, for example, has revealed that oceansurface temperature anomalies are a potential cause ofatmospheric temperature anomalies in successive seasonsand at distant locations.

Introduct


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-he changea'ility of weather varies widely in dierent parts ofthe world.

Weather has a tremendous in/uence on human settlementpatterns, food production, and personal comfort.

Extremes of temperature and humidity cause discomfort andmay lead to the transmission of disease0 heavy rain can cause/ooding, displacing people and interrupting economicactivities0 thunderstorms, tornadoes, hail, and sleet stormsmay damage or destroy crops, 'uildings, and transportationroutes and vehicles. 1torms may even $ill or in2ure people andlivestoc$.

3t sea and along ad2acent coastal areas, tropical cyclones(also called hurricanes or typhoons) can cause great damagethrough excessive rainfall and /ooding, winds, and waveaction to ships, 'uildings, trees, crops, roads, and railways,and they may interrupt air service and communications.

4eavy snowfall and icy conditions can impede transportation

and increase the fre*uency of accidents.

Int


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-he development of weather satellites since the5#6s has ena'led meteorologists to trac$ themovement of cyclones, anticyclones, their associatedfronts, and storms worldwide.

In addition, the use of radar permits the monitoring

of precipitation, clouds, and tropospheric winds.

-o predict the weather one wee$ or more inadvance, computers com'ine weather models, whichare 'ased on the principles of physics, with measuredweather varia'les, such as current temperatureand wind speed.

In tropical regions, 'y contrast, daily weathervariations are small, with regularly occurringphenomena and percepti'le change associated morewith seasonal cycles (dry weather and monsoons).7or some tropical areas, tropical cyclones themselves

are one of the more in/uential weather varia'les.

Int


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Climate


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8limate, conditions of the atmosphere at a particularlocation over a long period of time0 it is the longtermsummation of the atmospheric elements (and theirvariations) that, over short time periods,constitute weather.

3 region9s climate is generated 'y the climate system,which has vecomponents: atmosphere, hydrosphere, cryosphere, lit

hosphere, and 'iosphere. -he climate of a location is aected 'y

its latitude, terrain, and altitude, as well asnear'y water 'odies and their currents.

8limates can 'e classied according to the average and

the typical ranges of dierent varia'les, mostcommonly temperature and precipitation.

Introdu


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3ir temperatures have their origin in the a'sorptradiant energy from the 1un. -hey are su'2ect to

in/uences, including those of the atmosphere, oceanland, and are modied 'y them. 3s variation of radiation is the single most important factor aeclimate, it is considered here rst.

;uclear fusion deep within the 1un releases a treme

amount of energy that is slowly transferred to the surface, from which it is radiated into space.

ercent of this ener is not used

1AB3+ +3CI3-IA; 3;C -ED

h i l i l h i


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-he noon time elevation angle reaches a maximum latitudes north of the -ropic of 8ancer (G>.&H ;) around ?uand a minimum around Cecem'er GG. 1outh of the -ro8apricorn (G>.&H 1), the opposite holds true, and 'etweetwo tropics, the maximum elevation angle (56H) occurs tyear.

When the 1un has a lower elevation angle, the solar eneless intense 'ecause it is spread out over a larger area.

ariation of solar elevation is thus one of the main factoraccounts for the dependence of climatic regime on latitud

-he other main factor is the length of daylight. 7or latpole ward of !!.&H ; and 1, the length of day ranges from(winter solstice) to G% hours (summer solstice), whthe E*uator has a constant Ghour day throughout the ye

-he seasonal range of temperature conse*uently decfrom high latitudes to the tropics, where it 'ecomes les

the diurnal range of temperature.


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Af the radiant energy reaching the top of the atmosphere,

percent is a'sor'ed 'y Earths surface on average, 'ut this valuvaries signicantly from place to place, depending on cloudines

surface type, and elevation.

If there is persistent cloud cover, as exists in some e*uator

regions, much of the incident solar radiation is scattered 'ac$

space, and very little is a'sor'ed 'y Earths surface.

Water surfaces have low re/ectivity (%"6 percent), except in lo

solar elevations, and are the most e@cient a'sor'ers. 1no

surfaces, on the other hand, have high re/ectivity (%6"#6 percen

and so are the poorest a'sor'ers. 4ighaltitude desert regio

consistently a'sor' higherthanaverage amounts of sol

radiation 'ecause of the reduced eect of the atmosphere a'ov

them.

Eect on atmosph


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-he emitted wavelengths are mainly 'etween & and 66 Km (6.666G and 6.66% ininteract dierently with the atmosphere compared with the shorter wavelengradiation. ery little of the radiation emitted 'y Earths surface passes directlyatmosphere.

3n additional G> percent or so of the incident solar radiation is a'sor'ed on avatmosphere, especially 'y water vapour and clouds at lower altitudes and 'y o

the stratosphere.

3'sorption of solar radiation 'y oJone shields the terrestrial surface frultraviolet light and warms the stratosphere, producing maximum temperaturesH8 (& to &6 H7) at an altitude of &6 $m (>6 miles). Dost atmospheric a'sorptionat ultraviolet and infrared wavelengths, so more than 56 percent of the visi'le psolar spectrum, with wavelengths 'etween 6.% and 6. Km (6.6666G to 6.6666> inthe surface on a cloudfree day.

isi'le light, however, is scattered in varying degrees 'y cloud droplets, aand dust particles.


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-he 'lan$eting eect is greatest in the presence of low

clouds and wea$est for clear cold s$ies that contain little

water vapour. Without this eect, the mean surface

temperature of & H8 (&5 H7) would 'e some >6 H8 colder.

8onversely, as atmospheric concentrations of car'on

dioxide, methane, chloro/uorocar'ons, and othera'sor'ing gases continue to increase, in large part owing

to human activities, surface temperatures should rise

'ecause of the capacity of such gases to trap infrared

radiation.

-he exact amount of this temperature increase, however,remains uncertain 'ecause of unpredicta'le changes in

other atmospheric components, especially cloud cover.

3n extreme example of such an eect (commonly du''ed

the greenhouse eect) is that produced 'y the dense

atmosphere of the planet enus, which results in surfacetem eratures of a'out %& H8 ## H7 . -his condition


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Ecosystem


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3n ecosystem can 'e categoriJed into its nonliving constituents,including minerals, climate, soil, water, sunlight, and all other nonliving

elements, and its 'iotic constituents, consisting of all its living mem'ers.

Bin$ing these constituents together are two ma2or forces: the /owof energy through the ecosystem, and the cycling of nutrients within theecosystem.

-he fundamental source of energy in almost all ecosystems is radiantenergy from the sun. -he energy of sunlight is used 'y theecosystems autotrophic, or selfsustaining, organisms.

8onsisting largely of green vegetation, these organisms are capa'leof photosynthesisMi.e., they can use the energy of sunlight to convertcar'on dioxide and water into simple, energyrich car'ohydrates.

-he autotrophs use the energy stored within the simple car'ohydrates toproduce the more complex organic compounds, such as proteins, lipids,and starches, that maintain the organisms life processes. -he autotrophic

segment of the ecosystem is commonly referred to as the producer level.

Introdu

Arganic matter generated 'y autotrophs directly or indirectly


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Arganic matter generated 'y autotrophs directly or indirectlysustains heterotrophic organisms.

4eterotrophs are the consumers of the ecosystem0 they cannoma$e their own food. -hey use, rearrange, and ultimatelydecompose the complex organic materials 'uilt up 'y theautotrophs. 3ll animals and fungi are heterotrophs, as are

most 'acteria and many other microorganisms.

-ogether, the autotrophs and heterotrophs form various trophic(feeding) levels in the ecosystem

3ctually, in many cases the food chains of the ecosystem overlapand interconnect, forming what ecologists call a food we'.

-he nal lin$ in all food chains is made up of decomposers, thoseheterotrophs that 'rea$ down dead organisms and organic wastes

3 food chain in which the primary consumer feeds on living plantsis called a graJing pathway0 that in which the primary consumefeeds on dead plant matter is $nown as adetritus pathway.


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Energy and carbon enter ecosystems through photosynthesis, are incorporateinto living tissue, transferred to other organisms that feed on the living and deplant matter, and eventually released through respiration. Most mineral nutrieon the other hand, are recycled within ecosystems.

Ecosystems are controlled both by external and internal factors. External factoalso called state factors, control the overall structure of an ecosystem and thethings work within it, but are not themselves inuenced by the ecosystem.

!he most important of these is climate. "ainfall patterns and temperatureseasonality determine the amount of water available to the ecosystem and thsupply of energy available #by inuencing photosynthesis$.

%arent material, the underlying geological material that gives rise to soils,determines the nature of the soils present, and inuences the supply of minernutrients.

!opography also controls ecosystem processes by a&ecting thingslike microclimate, soil development and the movement of water through a sys

!his may be the di&erence between the ecosystem present in wetland situatea small depression on the landscape, and one present on an ad'acent steephillside.

Ecosystem proc

(ther external factors that play an important role in ecosystem functioning include


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p y p y gtime and potential biota.

Ecosystems are dynamic entities)invariably, they are sub'ect to periodicdisturbances and are in the process of recovering from some past disturbance.

!ime plays a role in the development of soil from bare rock and the recovery of acommunity from disturbance. *imilarly, the set of organisms that can potentially bepresent in an area can also have a ma'or impact on ecosystems.

Ecosystems in similar environments that are located in di&erent parts of the worldcan end up doing things very di&erently simply because they have di&erent pools ofspecies present.

+nlike external factors, internal factors in ecosystems not only control ecosystemprocesses, but are also controlled by them.

Conseuently, they are often sub'ect to feedback loops.

While the resource inputs are generally controlled by external processes like climateand parent material, the availability of these resources within the ecosystem iscontrolled by internal factors like decomposition, root competition or shading.

(ther factors like disturbance, succession or the types of species present are alsointernal factors.

-uman activities are important in almost all ecosystems. lthough humans existand operate within ecosystems, their cumulative e&ects are large enough to

inuence external factors like climate.

%rimary production / %rimary production is the production of organic matter


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y p y p p gfrom inorganic carbon sources. (verwhelmingly, this occurs throughphotosynthesis.

!he energy incorporated through this process supports life on earth, while thecarbon makes up much of the organic matter in living and dead biomass, soilcarbon and fossil fuels. 0t also drives the carbon cycle, which inuencesglobal climate via the greenhouse e&ect.

!hrough the process of photosynthesis, plants capture energy from light anduse it to combine carbon dioxide and water toproduce carbohydrates and oxygen.

!he photosynthesis carried out by all the plants in an ecosystem is called thegross primary production #1%%$. bout 234567 of the 1%% is consumed in plan

respiration. !he remainder, that portion of 1%% that is not used up byrespiration, is known as the net primary production #8%%$.

!otal photosynthesis is limited by a range of environmental factors. !heseinclude the amount of light available, the amount of leaf area a plant has tocapture light #shading by other plants is a ma'or limitation of photosynthesis$,rate at which carbon dioxide can be supplied to the chloroplasts to supportphotosynthesis, the availability of water, and the availability of suitable

temperatures for carrying out photosynthesis.

Cecomposition /


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p

!he carbon and nutrients in dead organic matter are broken down by a group ofprocesses known as decomposition.

!his releases nutrients that can then be re9used for plant and microbial production,and returns carbon dioxide to the atmosphere #or water$ where it can be used forphotosynthesis.

0n the absence of decomposition, dead organic matter would accumulate in anecosystem and nutrients and atmospheric carbon dioxide would be depleted.

pproximately :67 of terrestrial 8%% goes directly from plant to decomposer.

;ecomposition processes can be separated into three categories)leaching,fragmentation and chemical alteration of dead material. s water moves throughdead organic matter, it dissolves and carries with it the water9soluble components.

!hese are then taken up by organisms in the soil, react with mineral soil, or aretransported beyond the coneaching is more important in wet environments, and much less important in dryones.

;utrient cycle :


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Ecosystems continually exchange energy and carbon with the wider environment? mineral nutrients, oother hand, are mostly cycled back and forth between plants, animals, microbes and the soil.

Most nitrogen enters ecosystems through biological nitrogen


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Weather, climate, and Ecosystem.pptx

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