Reference: Meteorology Today 7th

Meteorology

INTRODUTION

Temperature & Heat Transfer

Seasonal & Daily Temperatures

Humidity, Condensation, Clouds

Condensation

Stability & Cloud Development

Precipitation

Pressure & Winds

Winds

Winds : Global System

Air Masses & Front

Thunderstorms

TORNADOES

Hurricane

Online Quiz

Part1: Scales of Atmospheric Motion

Eddy

Whirl of air, Come in different sizes

Small volume of air behaves differently from the large flow in which it resides

Eddies are down wind from the obstacle

Caused by encountering an obstacle

Part2: Mesoscale

Local Winds (Mesoscale)

Caused by topographic effects or variations in local surface composition

Include
1. Land & Sea Breezes
2. Valley & Mountain Breezes
3. Chinook Winds (Foehn Winds)
4. Katabatic Winds (Fall Winds)
5. Santa Ana Winds
6. Haboobs Winds (Desert Winds)
7. Dust Devils
8. Country Breezes

Part3 : MONSOON

MONSOON

Seasonal change in global circulation
Refers to Seasonal reversal of wind direction

Caused by Alternation between 2 weather patters

Doesn’t mean rainy season

The End

Online Quiz

Adiabatic Lapse Rates

Adiabatic process

dry adiabatic rate DAR = 10°C/Km
If parcel of unsaturated air expands & cools, or compresses & warms, with no interchange of heat withits surroundings

The Rate of adiabatic cooling or warming remains constant “only to unsaturated air”

Wet adiabatic rate WAR ≈ 6°C/Km
As the rising air cools, its RH increases, & at the Td, RH becomes 100%

Further lifting results in condensation, a cloud forms, & latent heat is released inside the rising air parcel

The air no longer cools at the DAR but at a lesser rate. Because the heat added offsets some of the cooling due to expanding

Lifted Condensation Level (LCL)

The height at which air that is cooling at the DAR becomes saturated & condensation begins

Processes that Lift Air

Orographic Lifting: forced over a mountain

Convergence forced to rise as it collides

Frontal Wedging: air is forced up due to difference in air T or ρ

Localized Convective Lifting differential  heating, Air is forced to rise to heating air & lowering its density

Air Parcels

Imaginary volume of air
– a few hundred m³

ASSUMPTION
1. no heat is transferred into, or out of it
2. Acts independently of the surrounding air
3. HIGHLY IDEALIZED

We use them to
1. Determines if the air will rise or sink by comparing parcel of air to its surrounding
2. predict if clouds will form

Adiabatic Lapse Rates ALR

WALR & DALR help us to
1. Understand if a parcel will rise or sink
1. Determines if a cloud will form
2. Determines type, & height of clouds

Environmental Lapse Rate (ELR)

Actual measureable T change with height

Atmospheric stability

Stable Air (Tair < Tsur.)

If a parcel cooler than the surrounding, it would be more dense, so sink back to it’s original position

Air resists vertical (up & down) motion

Air is in stable equilibrium when it tends to return to its original position

Unstable Air (Tair > Tsur.)

If a parcel warmer than the surrounding, it would be less dense, so rise to an altitude where it’s T equaled that of surrounding

Air that is in unstable equilibrium will move away from its original position

Stability & Daily Weather

If stable air is forced up, the associated clouds have little vertical thickness & precipitation is light

Clouds associated with unstable air are towering & accompanied by heavy rain

Thunderstorms produced by the unstable air that caused by the passing hurricanes

Changes in Stability

Stability is enhanced by the following
1. Radiation cooling of surface after sunset
2. The cooling of an air mass from below
3. General subsidence within an air column (sinking)
Stable atmosphere are cooling from below & warming aloft

Instability is enhanced by the following
1. Solar heating warming the lower atm
2. The heating of an air mass from below
3. Upward movement of air
4. Radiation cooling from cloud tops
Unstable atmosphere are heating from below & colling aloft

Vertical Air Movement

Subsidence downward motion of air

Stabilizes the air if the air above is warmed

Can result in the evaporation of clouds

The End

Online Quizzes

1st : Haze & Foge

2nd : Clouds

Haze & Fog

Haze

layer of dust or salt particles suspended above the region

tiny dry haze particles scatter some rays of sunlight, & allowing others to penetrate air.

The scattering effect of dry haze
1. bluish color when viewed against a dark- colored background
2. yellowish when viewed against a light- colored background

As the air cools during the night, the RH increases, & When the RH = 75٪, condensation may begin on the most active hygroscopic nuclei, producing a wet haze

FOG

cloud with its base at or near the ground

Types of Fog:
Fogs formed by Cooling
1. Radiation
2. Advection
3. Upslope
Fogs formed by Evaporation
1. Steam
2. Frontal

Radiation Fog

Fog formed During the night, when The ground cools the air close to the surface
– Tend to form on clear, relative calm night when cool, moist air is overlain by drier air & rapid Radiational Cooling occurs
– Clear Skies
– Fairly high RH
– Cold air sinks in valleys
– Dissipate يبدد after sunrise

Advection Fog

Fog formed by horizontal movement of air, if Warm moist air is blown over a cold surface
– Advection = horizontal movement
– Turbulence (wind) is needed to make it thick

Upslope Fog

Fog formed as humid air moves up a gradual sloping plain or mountain (or as Moist air rises, cools, & condenses over elevated terrain)
– it cools as moves up, formed at dew point
– Most likely to form along an Irregular Coastline at the headland
– headland: region of land extended seaward
– Ex: Great Plains

Steam Fog

Fog formed as Cool air moves over warm water
– Rising air cools & condenses
– Moister added into the layer

Frontal Fog

as warm air is pushed over a colder one
– If cold air is near dew, point rain evaporate & produce fog
– Results addition of H₂O(g) into cool air layer

Fog That Forms by Mixing

clouds

cloud

any visible aggregate of tiny droplets of water or ice crystals, or mixture of both

Cloud drops, on average 10 um in diameter

Come in a variety of shapes & sizes

Found at a large range of altitudes from the surface to the stratosphere

Help meteorologists figure out what’s going on in the atmosphere

Recipe for a Cloud
1. Cloud Condensation Nuclei (CCN): the surface for water vapor to condense upon
2. Rising Air: Causes adiabatic cooling
3. Water Vapor

Why do you need CCN?

Without CCN the RH would have to be much greater than 100% to form a cloud drop

hygroscopic particles is water-seeking or liking, vapor rapidly condenses on their surfaces, such as Sea salt

Hydrophobic Particles water repelling, resist condensation, can still serve as nuclei when RH is > 100%

Why are cloud drops so TINY?!

The drops grow FAST & other aerosol want water too

H₂O is split up over a lot of little dropsinstead of a few big ones

Cloud Classification

History & Classification System

Ancient astronomers named the major stellar constellations about 2000 years ago

Lamarck proposed the first system for classifying clouds in 1802

One year later, L.Howard, developed a cloud classification system that found general acceptance

Howard’s system used Latin ‘“words” to describe clouds as they appear to a ground observer
1. sheet-like cloud = stratus = layer
2. puffy cloud = cumulus = heap
3. wispy cloud = cirrus = curl of hair
4. rain cloud = nimbus = violent rain

These system has 4 basic cloud forms, & Other clouds described by combining basic types.
nimbostratus : rain cloud, shows layering
cumulonimbus : rain cloud having pronounced vertical development (puffy)

Then, Abercromby & brandsson published a classification system that is still in use today

Abercromby-brandsson system

include:
– 10 principal cloud forms
– 4 primary cloud groups

Each group identified by:
1. the height of the cloud base
2. their appearance

Groups
1. high clouds
2. middle clouds
3. low clouds
4. vertical clouds

The End

Online Quiz

Special Properties of water

– easily changes from solid to liquid to gas
– Ice is LESS dense than water so it floats (Ice cubes, ice bergs, & ice caps)
– Has an unusually high heat capacity (3 times that of land)
– The angle in the water molecule = 104°

body of the earth is made up of 70% H₂O

Oceans account for most of water (>97%)
Ice sheets in Antarctica & Greenland (< 3%)
Atmosphere has only a little (0.001%)

The water (hydrologic) cycle

EVAPORATION (Require Energy)

Process by which liquid transformed into gas

Happens over Oceans, Lakes, Rivers & other “standing” bodies of water

Powered by the sun: Solar radiation heats up water molecules until they are “freed” from the liquid state

CONDENSATION (Release Energy) 

The change from a gas to a liquid
Responsible for the formation of clouds

PRECIPITATION

Falling liquid or solid in the atmosphere

Balances Evaporation: Average annual precipitation equals evaporation

Happens over Land or Oceans

Returns the water to the ocean or soaks into the ground

TRANSPIRATION

release of H₂O(g) to atmosphere by plants

Plants uptake water through their roots that fell as precipitation

Not as important as evaporation

SUBLIMATION (Require Energy)

Conversion of a solid directly to a gas

EX: Gradual shrinking of unused ice cubes,  the rapid conversion of dry ice into gas.

How piles of snow tend to disappear even if air T never reaches above 32F (if air is dry)

DEPOSITION (Release Energy)

Conversion of a gas directly to a solid, without passing through an intermediate liquid phase

EX: Frost on a window pane (white frost, hoar frost… FROST)

EX: Frost the builds up in the freezer.. Was once part of your ice cube! 

Location of Processes

Evaporation exceeds Precipitation over Water (No plants), so no transpiration

Precipitation exceeds Evaporation over Land

Condensation happens everywhere

Water Vapor Content of Air

Humidity

The general term used to describe the amount of H₂O(g) in the air

Vapor Pressure

Total atm P attributable to its H₂O content

As more water vaporis added to dry air the vapor pressure increases

Saturation Vapor Pressure

Initially more molecules leave the surface of the water than return

SATURATION : Over time number of molecules leaving = the number molecules returning

Relative Humidity, Natural Change

1. Daily changes in T (daylight verses night T)
2. T changes that result as air moves horizontally from one location to another
3. T changes as air moves vertically in atm

Dew Point Temperature

The temperature which air needs to be cooled to reach saturation

measure of the actual moisture content of a parcel of air

The term dew point stems from the fact that during the night objects at the surface often cool below the dew-point are coated with dew

When dew point exceeds 65Fit is considered humid by most people

dew point > 75Fit considered unbearable

Dew

The condensation of water vapor on objects that have cooled to the dew-point
– They radiated away some of their heat
– A car will get dew before the cement since they cool at different rates
– More frequent on grass since plant Transpire & release H₂O(g) right near blade!

Dew is more likely to form on nights that are clear & calm than cloudy & windy Clear nights allow objects near the ground to cool rapidly by emitting IR, & calm winds mean the coldest air will be located at ground level, These atm conditions associated with large fair-weather, & high P systems.

the cloudy, windy weather that inhibits rapid cooling near the ground & the forming of dew often signifies the approach of a rain producing storm system. & These observations inspired the following folk rhyme:
1. When the dew is on the grass, rain will never come to pass.
2. When grass is dry at morning light, look for rain before the night!

Frost

Frost is NOT frozen dew
white or hoar frost: forms from deposition

RH & HUMAN DISCOMFORT

A good measure of how cool the skin can become is the “wet-bulb T” the lowest T that can be reached by evaporating water into air

Sensible Temperature T we perceive In cold weather, when the air is calm, higher than a thermometer might indicate

Heat-related problems

Hypothalamus gland: As this perspiration evaporates, rapid loss of water & salt can result in chemical imbalance that may lead to painful heat cramps. Excessive water loss through perspiring coupled with increasing body T may result in heat exhaustion fatigue, headache, nausea, & even fainting. If body T rises above 41°C, heatstroke can occur, resulting in complete failure of the circulatory functions. If body T continues to rise, death may result

Heat Index (HI)

Index combines air T with relative humidity to determine an apparent T

what the air T “feels like” to the average person for various combination of air T & relative humidity

MEASURING HUMIDITY

Psychrometer Common instrument, consists of 2 liquid-in-glass thermometers mounted side by side & attached to a piece of metal that has either handle or chain at one end
Hygrometers (Hair Hygrometer) hair to measure relative humidity, constructed on the principle “relative humidity increases, the length of hair increases”
Electrical hygrometer flat plate coated with a film of C. An electric current is sent across the plate. As H₂O absorbed, the electrical resistance of the C changes & translated into RH. commonly used in the radiosonde, which gathers atm data at various levels above Earth
Infrared Hygrometer Measures humidity by amount of IR absorbed by H₂O, & the dew cell determines the amount of H₂O in the air by measuring the air’s actual H₂O pressure

important Terms

EVAPORATION Require Energy, Process by which liquid transformed into gas, Powered by the sun
CONDENSATION Release Energy, The change from a gas to a liquid, Responsible for the formation of clouds
PRECIPITATIONF alling liquid or solid
TRANSPIRATION release of water vapor to atmosphere by plants
SUBLIMATION Require Energy, Conversion of a solid directly to a gas
DEPOSITION Release Energy, Conversion of a gas directly to a solid, without passing through an intermediate liquid phase
Humidity The general term used to describe the amount of H₂O(g) in the air
AH The MASS of water vapor in VOLUME of air
SH The MASS of water vapor in a unit of air compared to the remaining MASS of air (include water vapor) molecules
MR The MASS of water vapor in a unit of air compared to the remaining MASS of dry air
VP Total atm P attributable to its H₂O content
RH the ratio of the amount of H₂O actually in the air to the maximum amount of H₂O required for saturation at that particular T & P, or, ratio of the air’s H₂O content to its capacity
Dew Point T temperature which air needs to be cooled to reach saturation, measure of actual moisture content in air
Dew The condensation of water vapor on objects that have cooled to the dew-point
Frost NOT frozen dew, forms from deposition
Sensible T T we perceive In cold weather, when the air is calm, higher than a thermometer might indicate
wet-bulb T good measure of how cool the skin can become is the “” the lowest T that can be reached by evaporating water into air
HI Index combines air T with RH to determine an apparent T, what the air T “feels like” to the average, for various combination of air T & RH
Saturation VP When air is saturated VP exerted by motion of H₂O(g), Varies with T
Psychrometer Common instrument used to measuring RH, consists of 2 liquid in glass thermometers mounted side by side & attached to a piece of metal that has either handle or chain at one end
Hair Hygrometer measure RH, constructed on the principle “relative humidity increases, the length of hair increases”
Electrical hygrometer flat plate coated with film of C, electric current is sent across plate. As H₂O absorbed, the electrical resistance of the C changes & translated into RH
Infrared Hygrometer Measures RH by amount of IR absorbed by H₂O, & the dew cell determines the amount of H₂O in the air by measuring the air’s actual H₂O pressure

The End

Online Quiz

Important Terms

Circle of Illumination: Boundary separating the dark & light halves of the Earth

Earth’s Axis: Imaginary lines through the poles with Inclination 23.5°

Plane of the ecliptic: the plane of the orbit around the sun

Earth-Sun relationship

The distance between the Earth & the sun

average distance = 150 million km

Because earth orbital is ellipse the actual distance varies during year:
  – in January 147 MKm, closer to the sun
  – in July 152 MKm, Farther from the sun

The Earth has 2 principle motions

Rotation: spinning of Earth about its axis

Revolution: The earth revolves completely around the sun in an elliptical path in 365 days, Travels at nearly 113,000 km/hr

(Elliptical Orbit – Eccentricity ≈ 0.8)

Τhe Seasons

Variations distance DO NOT cause seasonal temperature change

Without the TILT we wouldn’t have seasons

The Seasons primarily due to:
1. Change in the length of daylight
2. Gradual change in angle of the sun at noon
3. amount of energy received at surface

The seasons are regulated by energy received at the surface that determined by:
1. Angle of sunlight that strikes surface:
– Overhead, perpendicularly, or directly: is more intense (or strongest intense)
– at Angle (θ) is less intense
2. how long sun shines (daylight hours): determine how warm the surface becomes

The change in day length & sun angle happens because: earth’s Rotation (earth’s orientation to sun constantly changes)

Length of Daylight & Solar Energy

During the summer in N latitudes, the sun is never very high above the horizon, so its radiant energy must pass through atm, & because of the increased cloud cover during the arctic S, much of the sunlight reflected before it reaches ground

Solar energy eventually reaches the surface in the N does not heat the surface effectively

A portion of the sun’s energy is reflected by ice & snow, while some of it melts frozen soil

The amount actually absorbed is spread over  a large area. So, even though N cities experience 24 hr of continuous sunlight on June 21, they are not warmer than cities S

Overall, they receive less radiation at the surface, & what radiation they do receive does not effectively heat the surface.

The Earth intercepts only a tiny percentage of the energy given off by the sun

Solstice & Equinoxes

Summer Solstice

– Occurs on June 21 or 22
– Tropic of CANCER (23.5°N latitud)
– Northern limit of the Sun’s rays
– First day of NH summer
– NH tilted toward the sun
– NH location experience LONGEST day
– ΝH location experience HIGHEST Sun θ
– SH location experience SHORTEST day
– SH location experience LOWEST Sun θ
– Farther from the equator → longer period of daylight (Arctic Circle has 24hr of SUN)

Winter Solstice

– Occurs on December 21 or 22
– Tropic of CAPRICORN (23.5° S)
– Southern limit of the Sun’s rays
– First day of NH winter
– NH tilted away from Sun
– NH location experience SHORTEST day
– ΝH location experience LOWEST Sun θ
– SH location experience LONGEST day
– SH location experience HIGHEST Sun θ
– Farther from the equator → longer period of daylight (Antarctic Circle has 24hr of SUN)

Equinoxes

mid way between the Solstices
– Vertical rays strike along the equator 0°
– Earth not tilted toward or away
– Autumnal Equinox: September 22 or 23
– Spring(Vernal) Equinox: March 21 or 22

Tilt

More Tilt (> 23.5°): More extreme seasons, Colder winters, & Warmer summers

Less Tilt  (<23.5): More mild seasons Cooler summers, & Milder winters

Tilt = 0 (NO TILT): No Seasons

– The location of Tropic of Cancer & Capricorn shift (Ex. 30° Tilt: tropic of Cancer 30°N & tropic of Capricorn 30°S )

– The Arctic & Antarctic circles shift 90-θ (Ex. 30° Tilt: Arctic Circle 60°N & Antarctic 60°S)

Temperature

Air T is important, Why ?

It’s the first thing we usually think when we talk about “weather”

vary on different time scales: Seasonally, daily, & hourly

vary all over the globe, by quite bit

Day Vs Night

1. On a sunny day, the air near the surface warmer than air above the surface
2. On a night, the air near the surface is colder than air above the surface

Temperature Inversion: The increase in T with increasing height above the surface (on a night)

Radiational Cooling: Radiation Inversion, Nocturnal inversions

What controls air temperature?

Differential Heating of Land & Water
Ocean Currents
Altitude
Geographic Position
Cloud Cover
Albedo

Land Vs Ocean

Differential Heating

Different surfaces absorb, emit, & reflect different amounts of energy, & This causes variations in air above each surface

Land HEATS or COOLS more rapidly so Variations over Land are GREATER

Ocean less variable, Why?
1. Surface T of water rises & falls slower
2. Water is highly mobile & mixes easily
3. Daily T changes are about 6m deep
4. Yearly ocean & deep lakes experience  variations through layer (200-660)m thick

Land are more variable, Why?
1. Heat not penetrate deeply into soil or rock & it remains near the surface
2. Rocks are not fluid… so no mixing
3. Daily T changes are 10cm down
4. Yearly T changes reach < 15m

Summer Vs Winter

During summer thick layer of water is heated while only a thin layer of land is heated

During winter the shallow layer of rock cools rapidly while the deeply heated water takes a longer time to cool

as surface water cools, becomes heavier & sinks, replaced with warmer less dense water from below, So water surface T not appear to change much

Opaque Vs Transparent

land surfaces are opaque, So heat is absorbed only at the surface

Water is transparent & lets energy from the sun penetrate to a depth of several meters

Specific Heat

amount of heat needed to raise T of 1g H₂O by 1°C (3 times greater than 1g of soil or rock) 

The OCEANS require More Reheat to raise its T same amount as an equal quantity of land

Evaporation

greater from Oceans than from Land Because There’s more water molecules (Intuitive!)

Energy is required to evaporate water: When energy is used to evaporate water it is not available for heating

WATER WARMS MORE SLOWLY THAN LAND!

Which Hemisphere (N or S) has larger T variations? & Why?

NH, there is more ocean & little land to interrupt the oceanic & atm circulation

THE END

Online Quiz

Learning

Important terms

Energy ability or capacity to do work, result from motion such as kinetic energy
Matter anything has mass & occupies space
Kietic energy (k) energy from motion
Calorie: amount of heat required to raise T of 1gH₂O from 14.6°C to 15.5°C (1cal = 4.186J)
kilocalorie: is 1000 calories, heat required to raise 1kgH₂O 18°C
Heat capacity: ratio of heat absorbed by substance to its corresponding T rise
                           C = Ε/ΔΤ [J/°C]
specific heat: heat capacity of a substance per unit mass, or amount of heat needed to raise the T of 1g of a substance 1°C(Ex. If heat 1g of water on a stove, it take 1cal to raise its T 1°C)
                  S = C/m = E/mΔΤ [J/g°C]
Sensible heat: the heat we can feel, “sense,” & measure with a thermometer

Important concepts

Work is done on matter if pushed, pulled, or lifted over distance

The energy within a body result of its motion, such as Potential & Kinetic energy

Temperature

average of Kinetic energy or average speed of atoms & molecules (energy within body that result of its motion)
describes how warm or cold an object is

Heat

ENERGY that TRANSFER from one body to another due to Differences in temperature

FLOW OF ENERGY due to Differences in T

After energy transferred it stored as internal energy

Latent Heat

energy required to change state of substance

Ex. H₂O(s) –> H₂O(l), T in these reaction stay constant & Heat is used to MELT the ice doesn’t produce a T change

Mechanics of Heat transmission

Ability to conduct are varies

Metals are better

Air INSULATOR (not conduct well)

Convection

Most common in atm (Only important for heating air in DIRECT contact with surface)

Thermals: circulation movement

Advection: horizontal movement

Radiation

Wavelengths (λ)

Is a distance between 2 crest
All λ travel at 300,000 km/s

Radiation emitted by the Earth

Earth emits radiation at longer λ than the sun (Emits less Energy)
> 95% of Earth radiation λ = (2.5, 30)μm (IR) 

Laws of rediation

All objects emit radiant energy over range of λ (EVERYTHING emits energy), Unless it’s at “absolute 0” if molecules stop

Hotter objects radiate more energy in the form of short λ than cooler objects

Stephan-Boltzman Law: Hotter objects radiate more total E per unit area

Blackbodies

such as Sun & Earth

Earth’s radiative equilibrium T = 255°k = -18°C = 0°F

Why isn’t this average surface T? atm IS NOT black body (Gases selective absorbers, absorb, & emit IR)

Greenhouse Effect

Gases are most effective absorbers of radiation & play primary role in heating atm

1. H₂O, O₂, O₃ absorb most of energy in atm
2. CO₂ is important at long λ (IR)
3. “Openings” are atmospherec windows

Atmosphere warms planet

H₂O, CO₂ (called selective absorber) absorb outgoing IR & absorbed energy heating the air

GHG

The Earth’s average T = 33°C = 59°F

GHG “villain” in Global Warming Debate

GH Effect & Global Warming NOT same thing

Without GH Earth would be uninhabitable!

Human activity may be making atm more efficient at retaining long wave emissions from the Earth

Reflected & Scattered

What Happens to Incoming Radiation?

Absorbed, Transmitted, Reflected, Scattered
DEPENDS ON λ

Scattering 

produces large number of weaker rays

Air molecules tend to selectively scatter

Blue Skies, Red Suns, & White Clouds duo to scattering

Reflection

bounces off at same angle & intensity

Reflection & Albedo: Energy is returned to space via reflection & emission

ALBEDO: percentage reflected (30%)
        5% from land & ocean
        25% from clouds & ice

Clouds absorbers IR radiation & effect of heating the earth depends on type of cloud

The effect of heating depends on type of cloud
1. Thick cloud absorbs the most of outgoing IR, & re-radiating it back to the surface (Warm cloudy nights)
2. High Thin Clouds Tend to WARM the surface by transmit incoming SW & Absorb outgoing LW & re-emit it back down
3. Low Thick Clouds Tend to COOL the surface by block incoming SW, have high albedo so reflect SW back to space

On average: clouds Cool the Earth

Note. SW = Short Wave, LW = long wave

T decrease in troposphere, Why

Surface warms the traposphere (The atm is HEATED from the GROUND UP)

Whether specific clouds will warm or cool surface depends on

1. time of day
2. Cloud’s thickness & height above surface
3. Surface with Liquid, dry Land, or ice

Earth’s average T constant due to

balance of incoming & outgoing radiation (black body)

Seasons-Regulated by

amount of solar energy received by surface

Why don’t tropics keep getting hotter & poles colder?

Movement of atm & oceans transfer energy from the equator to the poles

energy imbalance (unequal heat) drives ocean currents & winds (Weather)

Earth-Sun Relationships

The End

INTRODUTION

Temperature & Heat Transfer

Seasonal & Daily Temperatures

Humidity, Condensation, Clouds

Condensation

Stability & Cloud Development

Precipitation

Pressure & Winds

Winds

Winds : Global System

Air Masses & Front

Thunderstorms

TORNADOES

Hurricane

Online Quiz

Learning

Pdf

الارض، مُقدمة

بدأ تاريخ الأرض والمجموعة الشمسية بسحابة سديمية Primordial Nebula من غازات وغبار كوني

نشأ بمركز السدیم دوامة كبيرة أدت لتدافع مادته نحو داخله فيما يعرف بالانكماش الجذبي Gravitational Attraction

استمر الانكماش فازداد الضغط والحرارة بجوفه فأدى لبدء تفاعلات نووية أشعلت الهيدروجين فأضاءت الشمس التي كانت خاضعة لقوتين متعادلتين هما الطاقة الحرارية من جوفها التي تزيد حجمها والانكماش الجذبي الذي يقلص حجمها فاستقرت حتى يومنا هذا

حدثت دوامات صغيرة بأطراف السديم أدت لنشوء الكواكب التسعة المحيطة بالشمس ونظرا لصغر حجم السديم لم تصل درجة حرارة جوفها لدرجة بدء التفاعلات النووية فبقيت الكواكب أجسامة باردة غير مضيئة

الأرض والكواكب القريبة من الشمس خضعت اثناء تكاثف سديمها للرياح الشمسية التي طردت الغازات المكونة للسدیم وبقيت العناصر الأكثر ثقلا وكذلك دقائق الغبار الكوني التي تجمعت فشكلت الأرض الصلبة

جاءت مرحلة النشاط البركاني الشديد التي دفعت كميات كبيرة من الغازات لجو الارض اهمها بخار الماء الذي هطل مكونا مياه البحار واصبح هواء الارض مكونا من غازات مثل كبريتيد الهيدروجين والامونيا والارغون والهيليوم والنيتروجين وغيرها،

الاكسجين لم يكن موجود فكان الجو مختزل Reducing

كانت الأشعة فوق البفسجية تصل لسطح الارض اذ لم يكن بغلاف الأرض ما يمنعها من الوصول وقد فككت او تفاعلت هذه الاشعة عالية الطاقة مع بعض اكاسيد الغازات كبخار الماء مثلا محررة الأكسجين غير أن هذا الأكسجين الحر كان يستهلك بسرعة من الغازات المختزلة، سميت هذه المرحلة مرحلة التمثيل الكيميائي chemosynthesis

قبل 3500 مليون سنة بدأت كائنات حية كالبكتيريا بالوجود على الأرض والتي لا تحتاج الأكسجين بل تاخذه من عمليات كيميائية ، غير أن اهم ماكانت تقوم به انها كانت تاخذ ثاني اكسيد الكربون من الجو لتصنع غذائها بعملية التمثيل الضوئي Photosynthesis

كانت هذه الكائنات تطلق الأكسجين الحر الذي ادي لظهور الكائنات الحية التي تحتاج الأكسجين

الأرض شهدت عمليات جيولوجية نتج عنها تكوين المعادن كالحديد والفضة والذهب والرصاص والماس والفوسفات وتكونت مصادر طاقة احفورية كبترول وغاز وفحم حجري

More than 150 people die each year in USA from floods & flash floods, more than any other natural disaster

Why do we study Meteorology?

1. Daily Weather: how we plan our days
2. Severe Weather: damage, & loss of life 
3. Climate Change: quality of life, water & food supplies

Severe Weather Includes

tornadoes, hurricanes, snow storms, floods, thunderstorms…etc

Recent Weather Events

1. Hurricane Sandy: 2012, > 253 people killed in 7 countries, Cost estimated at 65.6B$, which would make it the 2nd costliest Atlantic Hurricane behind only Katrina.
2.  Joplin Tornado: 2011, 158 people killed & > 1,100 injured, It was dead lies tornado in America since 1947
3.VOG:2012, Trade Wind Weaken (respiratory complaints, headache, watery eyes, severe sinus infections), sulfur dioxide SO₂ gas & sulfate SO₄ aerosol which can cause acid rain/acid particles
4.Great Plains Drought: 2012, Worst hit region is the Central Great Plains, Critical for agriculture!

Meteorology

Is the study of atm & its phenomena
– mathematical science ❤
– The term goes back to Aristotle who wrote a book about meteorology
– Meteor means “high in the air”, Weather instruments in the 6th century

Weather

The state of the atm at any given time

Weather elements: Air T & P, Humidity, Clouds, Precipitation, Visibility, & Wind

Climate

sum of all statistical weather information (Average range of “weather element” over long period of time)

description of aggregate weather conditions

Includes extreme weather event (Droughts, heat wave, & cold snaps)

Climate changes on geological time scales such as ice ages

Climate VS Weather

Climate is what you expect, & weather is what you get

Atmospheric Compositions

Evolution of the atm

1. First atm: H & He, 4.6 BY ago, swept away by solar winds, & escaping hot surface
2. Primeval Phase: mostly CO₂, N₂, H₂O, little CH₄, NH₃, SO₂, HCl
3. Μodern Phase: 78%N, 21%O, 1%Ar, <1% other gases & aerosols

After 4 BY, surface cooled, Water vapor to condense into clouds so rain, Oceans, & rivers formed

CO₂ dissolves in H₂O: rain & ocean “washed out” CO₂, cooling the planet

O₂ building up in the atmosphere: After life emerged, photosynthetic bacteria emerged

Source of atm gases was OUTGASSING release from rock through volcanic eruptions & meteorites impact

Μodern Phase Composition

78% Nitrogen N₂
21% Oxygen O₂
< 1% Argon Ar
Carbo (–dioxide CO₂, -monoxide CO)
N (-dioxide NO₂, -oxide NO), Nitrous N₂O
Sulfer oxide SO, Hydrogen H₂, Helium He
Methan CH₄, & Ammonia NH₃
Ozone O₃, & Water vapor H₂O(g)
aerosols: tiny solid & liquid particle:
– dust, & smoke
– sea salt, & biogenic particle
– pollution, & volcanic ash

Where did all the Nitrogen come from?

1. N₂ is volatile in most of its forms
2. N₂ unreactive with materials that make up the solid earth
3. N₂ stable in solar radiation environment

– Over geological time, it has built up much greater than O₂
– It is an important component of life on earth (N-Cycle)

Why is Argon Third?

1. formed by radioactive decay of potassium isotope, & Released into atm by volcanic activity
2. inert gas, nonradioactive, so gradually accumulates in atm

-Used in Neon Lights

Where does oxygen come from?

1. Primary way is photosynthesis (98%)
2. The breakup of water molecules by ultraviolet radiation (1-2%)

Ozone O₃

concentrated above surface in stratosphere (good) & in Troposphere (poor)

Protect us from UV rays (what gives us sun burns)

Ozone Hole: in the Antarctic, though one happened in Arctic

Montreal Protocol

water vapor H₂O(g)

variable over the surface of the earth (0-4% by volume)

most abundant GHG: Heats atm (Releases or absorbs energy if it changes states )

Methan CH₄

GHG
from cows, wetlands, & rice pattie
low oxygen environment

Carbon dioxide CO₂

GHG

from respiration, combustion, & evaporation

Global Climate Change

present in tiny amouont ≈ 0.0387% ≈ 387ppm (increase since 1960s)

an efficient absorber of energy emitted by the sun!

atm Provides

air we breath
protection from damaging of UV radiation

Thermal Structure

as altitude (height) increases

layer Rapidly thins (density decreases)
P decreases (Not at a constant rate)
near surface air more dense, & Decreases rapidly at first then more slowly

P decreases as altitude increases

Layers of atm VERY THIN: 99% is within 30km

Half atm is lies below 5.6km

Standard atm P = 1013.25mb = 1013.25hPa = 29.92Hg

Air is HIGHLY compressible

What happen if astronaut exposed his hand in Thermosphere?

not feel hot, not enough particles

how the current atm evolved?

1. Outgassing
2. Photosynthesis

Ionosphere [80-400]km

an electrically charged layer, Overlaps with Thermosphere, site of Aurora

No influence on daily weather

Important for long wave radio transmission that Travel in straight lines & bounce off the Ionosphere
– at night F layer reflects AM waves
– in daylight D layer absorbs AM waves

Aurora [100-400]Km

Closely correlated with solar-flares & Appear in the night sky as overlapping curtains

phenomenon that forms as energetic particles from sun & interact with Earth’s atm

Aurora boreal (northern lights)

Aurora austral (southern lights)
 
Geographic location is important (Earth’s magnetic poles)

produce by solar wind distorts Earth’s magnetic field into magnetosphere & These particles interact with gases to produce aurora
– solar wind stream of charged particles
– magnetosphere has teardrop shape

The End

INTRODUTION

Temperature & Heat Transfer

Seasonal & Daily Temperatures

Humidity, Condensation, Clouds

Condensation

Stability & Cloud Development

Precipitation

Pressure & Winds

Winds

Winds : Global System

Air Masses & Front

Thunderstorms

TORNADOES

Hurricane