ATMOSFERİN GENEL DOLAŞIMI ATMOSPHERIC CIRCULATION ATMOSFERİN GENEL

ATMOSFERİN GENEL DOLAŞIMI ATMOSPHERIC CIRCULATION • ATMOSFERİN GENEL DOLAŞIMI, DÜNYA ETRAFINDAKİ HAVA AKIMINI İFADE ETMEKTEDİR. • GENEL DOLAŞIMIN TEMEL NEDENİ, YERYÜZÜNÜN EŞİT ŞEKİLDE ISINMAMASIDIR. • TROPİKLER CİVARINDA NET ENERJİ KAZANCI, KUTUPLAR CİVARINDA DA NET ENERJİ KAYBI VARDIR. • ENERJİDEKİ EŞİTSİZLİĞİN DENGELENMESİ İÇİN SICAK HAVA EKVATORDAN KUTUPLARA YUKARI SEVİYEDE, SOĞUK HAVA DA EKVATORA DOĞRU ALT SEVİYEDE TAŞINIR. • GENERAL CIRCULATION OF THE ATMOSPHERE IS MENT THE AIR CIRCULATION AROUND THE EARTH • THE MAIN CAUSE OF THE GENERAL CIRCULATION IS THAT OF THE UNEVEN HEATING OF THE EARTH • THERE ARE TOTAL ENERGY GAIN AROUND THE TROPICS AND TOTAL ENERGY LOOSE AROUND THE POLES. • TO BALANCE THE ENERGY GAIN AND LOOSE, WARM AIR MOVES TOWARD THE POLES AT THE UPPER LEVELS AND COLD AIR MOVES TOWARD THE EQUATOR AT THE LOWER LEVELS

SINGLE CELL CIRCULATION- -TEK HÜCRELİ MODEL • FARAZİYELER: • YERYÜZÜ ÜNİFORM OLARAK SU İLE KAPLI • DENİZ-KARA ARASINDA ISINMA FARKI YOK • RÜZGARLAR MEVSİMSEL DEĞİŞMEZ. • DÜNYA DÖNMÜYOR, DOLAYISIYLE CORİOLİS KUVVETİ YOK • TEK KUVVET BASINÇ GADYANIDIR. • HER İKİ YARIKÜREDE TERMAL OLARAK GELİŞMİŞ İKİ KONVEKSİYON HÜCRESİ SÖZKONUSUDUR. • BU HÜCRELERE HADLEY HÜCRESİ DENİR. • ASSUMPTIONS • EARTH COMPLATELY COVERED BY WATER • THERE IS NO HEATING DIFFERENCE BETWEEN LAND SEA • THERE IS NO SEASONAL WIND CHANGE • THERE IS NOT CORIOLIS FORCE • PRESSURE GRADIENT IS THE ONLY FORCE • THERE ARE TWO THERMALY CREATED CONVECTION CELLS IN THE BOTH HEMISPHERES WHICH IS KNOWN AS HADLEY CELL

TEK HÜCRELİ MODEL-HADLEY HÜCRESİ SINGLE CELL CIRCULATION-HADLEY CELL

TEK HÜCRELİ MODEL-HADLEY HÜCRESİ SINGLE CELL CIRCULATION-HADLEY CELL

THREE CELL CIRCULATION

ÜÇ HÜCRELİ MODEL -THREE CELL CIRCULATION

ÜÇ HÜCRELİ MODEL -THREE CELL CIRCULATION

ÜÇ HÜCRELİ MODEL -THREE CELL CIRCULATION

ÜÇ HÜCRELİ MODEL -THREE CELL CIRCULATION • POLAR HIGH • SUBTROPIC HIGH • EQUATORIAL LOW • POLAR EASTERLIES • PREVAILING WESTERLIES • TRADE WINDS-ALIZE • DOLDRUMS

30 0 6030 60 90 Warm Moist Air Rises Cool Dry Air Sinks Cold Moist Air Rises Very Cold Air Sinks HL H HH L L

30 0 6030 60 90 HL H HH L L Wind Moves from HIGH to LOW

Global Winds • The combination of pressure belts and the Coriolis Effect cause GLOBAL WINDS • Some examples of global winds are polar easterlies, westerlies, and trade winds Remember! Northern Hemisphere deflects right. Southern hemisphere defects left.

Global Winds — Polar Easterlies • Wind belts that extend from the poles to 60 ° latitude • Formed from cold sinking air moving from the poles creating cold temperatures

Global Winds — Westerlies • Wind belts found between 30 ° and 60° latitude • Flow towards the poles from west to east carrying moist air over the United States

Global Winds — Trade Winds • Winds that blow from 30 ° almost to the equator • Called the trade winds because of their use by early sailors

Global Winds — Horse Latitudes • Occur at about 30 ° north and south of the equator where the winds are very weak • Most deserts on the Earth are located here because of the dry air

Global Winds — Doldrums • Located along the equator where no winds blow because the warm rising air creates an area of low pressure

Global Winds

THREE CELL CIRCULATION

Global Winds – Influence of Continents

Global Winds – Influence of Continents

— COMPERATION KARŞILAŞTIRMA-

— COMPERATION —

INTERTROPICAL CONVERGENCE ZON

JET RÜZGARLARI JET STREAMS • VERY FAST MOVING CURRENT OF AIR NEAR THE TROPOPAUSE USUALLY IN THE NATURE OF MORE THAN 1. 000 MILES IN LENGTH, 100 -300 MILES IN WIDTH AND HAVING A DEPTH OF 3 KM. SPEED AT THE CENTRE IS AROUND 100 KNOTS(SOMETIMES 250 KNOTS). • WIND SPEED INCREASES WITH HEIGHT CAUSED BY THE WESTERLIES.

JET STREAMS Jet Stream: Currents of very fast winds in the stratosphere; separates hot air from cold air

Jet Stream • The jet streams are narrow belts of high speed winds that blow in the upper troposphere and lower stratosphere • Separates warm air from cold air The term «jet stream» is often used to refer to the rivers of wind high in the atmosphere — above about 20, 000 feet — that steer storms. They also help determine locations of areas of high and low air pressure at the Earth’s surface.

JET STREAMS

JET STREAMS

JET STREAMS

JET STREAMS

JET STREAMS Jet Streams are also part of the general circulation Polar Jet situated at about 10 km AGL over the polar front Subtropical Jet situated above the subtropical highs at about 13 km AGL often visible as a plume of moisture extending from the tropics to the sub-tropical regions The jet streams exhibit a «wavy» pattern around the globe. .

JET STREAMS Jet Stream Formation — Polar Jet: boundary between warm air to the south and cold air to the north location of a large temperature gradient near the surface recall that tropopause height is proportional to the mean tropospheric temperature

JET STREAMS Jet Stream Formation — Polar Jet — pressure gradient alof Polar Jet: Hence, the large temperature gradient at the surface across the polar front creates a large pressure gradient aloft recall that the strength of the geostrophic wind is proportional to the magnitude of the pressure gradient force

JET STREAMS Jet Stream Formation — Polar Jet: Hence, the large pressure gradient aloft over the polar front generates a band of strong winds this is the jet stream!! — Q: During which season is the jet stream stronger, winter or summer? WINTER Q: Why does the jet stream shift northward during the summer? ? BECAUSE POLAR FRONT MOVES NORTHWAR

JET STREAMS Subtropical Jet: Forms on pole ward side of Hadley cell created largely through conservation of angular momentum = m. V. r

JET RÜZGARLARI- OTHER JET STREAMS • DİĞER JET RÜZGARLARI TROPİKAL DOĞULU JET RÜZGARLARI • HİNDİSTAN VE AFRİKA ÜZERİNDE YAZIN OLUŞUR STRATOSFERİK POLAR JET RÜZGARLARI • POLAR ENLEMLERDE, STRATOSFERİN TEPESİNE YAKIN YERLERDE OLUŞABİLİR. ALÇAK SEVİYE JETİ : • YERDEN BİRKAÇ YÜZ M. YUKARIDA OLUŞUR. • Other Jet Streams: • Trophical easterly jet streams • Low-level Jet over Central Plains of US • Polar Stratospheric Night Jet

RÜZGAR- WIND • HORIZONTAL AIR MOVEMENT IS CALLED AS WIND. • HORIZONTAL PRESSURE GRADIENT CREATES WIND. • WIND DIRECTION IS TOWARD LP FROM HP • THREE PROPERTIES OF THE WIND IS; • WIND DIRECTION • WIND STRENGHT (WIND SPEED) • WIND FREQUENCY

RÜZGARIN YÖNÜ- WIND DIRECTIONS • MAIN DIRECTIONS • EAST-WEST-NORTH-EAST AND COMBINATION OF THOSE LIKE NE-NW-SW SE AND NNE-NNW-SSE-SSW-WSW- WNW WINDS ARE ALWAYS LABELED BY THE DIRECTION WHERE THEY BLOW FROM ( NORTH WIND OR NORTHERLY WINDBLOWS FROM 000 DEGREE. )

RÜZGARIN ŞİDDETİ- WIND SPEED • WIND SPEED. • IT IS THE DISTANCE TAKEN AT A SPECIFIC TIME BY THE WIND(MILES/HOUR= KNOTS OR METER/SEC. )

RÜZGAR FREKANSI- WIND FREQUENCY • WIND FREQUENCY IS THE PERCENTAGE OF THE NUMBER OF EXISTING WIND IN A SPECIFIC PERIOD. • IT IS DESIGNATED BY MONTLY-SEASONALLY OR ANNUALLY.

RÜZGAR GÜLÜ- WIND ROSE • A WIND ROSE PROVIDES A METHOD OF REPRESENTING PREVAILING WINDS BY INDICATING THE PERCENTAGE OF THE WIND BLOWS FROM VARIOUS DIRECTIONS, • THE LENGTH OF THE LINES ON THE WIND ROSE INDICATES THE PERCENTAGES OF TIME THE WIND BLEW FROM THAT DIRECTION

Wind rose represents % of time the wind blew from different direction during January (10 yrs); prevailing wind is NW & least frequency is N

RÜZGAR GÜLÜ- BALLIE WIND ROS

NEWTON’S LAWS • NEWTON’S FIRST LAW OF MOTION STATES THAT IF THERE IS NO EXTERNAL FORCE LIKE FRICTION OR GRAVITY ACTING TO AN OBJECT, AN OBJECT KEEPS ITS STABILIY DURING ITS REST OR IN MOTION. IF IT IS MOVING, IT WILL CONTINUE MOVING AT A UNIFORM SPEED AND IN A STRAIGHT LINE. IT IS NOT THE SAME IF A FORCE IS EXERTED UPON IT. • NEWTON’S SECOND LAW STATES THAT THE ACCELERATION OF AN OBJECT IS DIRECTLY PROPORTIONAL TO THE NET FORCE ACTING ON THAT BODY AND INVERSLY PROPORTIONAL TO THE MASS OF THE BODY. • ACCELERATION IS DEFINED AS THE RATE OF CHANGE IN VELOCITY. • FORCE = ACCELERATION X MASS • F=m x a (constant m)

Newton’s Laws of Motion govern the motions of all objects including air. Newton’s First Law of Motion If no force is exerted on an object, its velocity will not change. Newton’s Second Law of Motion : F = ma The force on an object equals its mass times its acceleration. The first law represents a fundamental change from the mistaken notion that the natural state of things is be still. Any object resists attempts to change its speed or its direction of motion. This resistance to change is called inertia. Speed is the distance traversed divided by the time interval. Velocity is speed in a particular direction. If the direction of a moving object changes, its velocity also changes, even if the speed remains constant. Acceleration is the change of velocity divided by the time interval. Objects accelerate when their speed or direction of motion changes.

Forces and their Accelerations Newton’s Second Law ( F = ma ) enables us to predict changes in motion (i. e. , acceleration, a ) provided we know the forces acting on air. The four primary forces on air (and water) and their resulting accelerations are, 1. Weight (Gravity) , produces a downward acceleration, g = 10 m s -2 at the surface of the Earth. 2. The Pressure Gradient Force produces an acceleration, a pg from a point of high pressure to a point of low pressure that is proportional to the pressure difference between the two points divided by the distance between the points 3. Friction ( viscosity for fluids) produces an acceleration, a f in the direction opposite the motion and is proportional to the speed of the wind or current. Friction acts to reduce all relative motions (e. g. , shear). 4. The Coriolis Force (a consequence of Earth’s Rotation) produces an acceleration, a cor to the right of the motion in the North Hemisphere, that is proportional to the speed of the wind or current (and to the sine of the latitude). Buoyancy is a residual force that results when density differences cause an imbalance of weight and pressure in air or any fluid.

PRESSURE GRADİENT FORCE ( PGF ) • pressure gradient: high pressure low pressure • pressure differences exits due to unequal heating of Earth’s surface • spacing between isobars indicates intensity of gradient • flow is perpendicular to isobars

WİNDS İN THE UPPER AİR: GEOSTROPHİC BALANCE • Now the wind speed/direction is simply a balance between the PGF and CE. • This is called GEOSTROPHIC BALANCE. • Upper air moving from areas of higher to areas of lower pressure undergo Coriolis deflection • Air will eventually flow parallel to height contours as • the pressure gradient force balances with the Coriolis f orce. Friction is very small in the upper air : FFCEPGF t V

PRESSURE GRADIENT FORCE- BASINÇ GRADYAN KUVVETİ • IF WE HAVE LARGE PRESSURE GRADIENT THAN IT IS CALLED « STRONG PRESSURE GRADIENT » • IF WE HAVE LITTLE PRESSURE GRADIENT IT IS CALLED» WEAK PRESSURE GRADIENT » • PGF IS PERPENDICULAR TO THE ISOBARS. • STRENGHT OR MAGNITUDE OF THE PGF IS ONLY RELATED TO PRESSURE GRADIENT.

PRESSURE GRADIENT FORCE THE PRESSURE GRADİENT FORCE (PGF) The pressure gradient force, like any other force(vector) , has a MAGNİTUDE AND A DİRECTİON : DİRECTİON — the pressure gradient force direction is ALWAYS directed from HİGH TO LOW pressure and is always PERPENDİCULAR to THE İSOBARS MAGNİTUDE — is determined by computing the pressure gradient

PRESSURE GRADIENT FORCE The Pressure Gradient Force — example Q: What is the direction of the PGF at points A, B, C, D, E Q : At which location is the PGF largest? ANSWER B Q : At which location is the PGF weakest? ANSWER

PRESSURE GRADIENT FORCE DEFLECTION OF A PARCEL ALOFT, Notice that: At the beginning parcel is moving from south to north, but finally, the parcel is moving from west to east (westerly) THE PGF İS EQUAL AND OPPOSİTE TO THE CORIOLIS FOR

CORIOLIS FORCE THE CORİOLİS FORCE ARİSES DUE TO THE FACT THAT THE EARTH İS ROTATİNG PROPERTİES OF THE CORİOLİS FORCE : ACTS ON OBJECTS NOT RİGİDLY ATTACHED TO THE EARTH ALWAYS ACTS TO DEFLECT AN OBJECT TO THE RİGHT (LEFT) OF İTS DİRECTİON OF MOTİON İN THE NORTHERN (SOUTHERN) HEMİSPHERE MAGNİTUDE İS ZERO AT THE EQUATOR, MAXİMUM AT THE POLES MAGNİTUDE DEPENDS ON THE ROTATİON RATE OF THE EARTH – THE MAGNİTUDE WOULD İNCREASE İF THE EARTHS ROTATİON RATE İNCREASED İF THE EARTH WERE NOT ROTATING, THE CORİOLİS FORCE WOULD BE ZERO

CORİOLİS KUVVETİ — CORIOLIS FORCE (CF) • THE DEFLECTION DEGREE OF THE MOVING OBJECT RELATED TO THE CORIOLIS FORCE IS BASED ON. ROTATION OF THE EARTH • LATTITUDE OF THE OBJECT • SPEED OF THE OBJECT • NOTE: CF increases with increasing all three above

CORIOLIS FORCE • PROPERTIES OF THE CORIOLIS FORCE, • The coriolis force is LARGER for parcels MOVING AT FASTER SPEEDS , it is ZERO if a parcel IS NOT MOVING • The coriolis force is NOT THAT LARGE for SLOW-MOVING objects or for those moving over SHORT DISTANCES • NOTE: The coriolis force is an » APPARENT » force that arises solely due to the fact that the EARTH IS ROTATING. Therefore, it can ONLY CHANGE A PARCEL’S DIRECTION , it CAN NOT affect its SPEED.

GEOSTROPHIC WIND DEFINITION OF GEOSTROPHIC WIND When the isobars are STRAİGHT, PARALLEL LİNES , and the only two forces acting on a parcel are the PGF and the CF , then the wind is called the GEOSTROPHİC WİND PGF and CF are equal in strength (magnitude ) and opposite in direction The geostrophic wind is always parallel to the isobars

JEOSTROFİK RÜZGAR-GEOSTROPHIC WIND • CONDITIONS FOR GEOSTROPHIC WIND • THERE IS NO FRICTION • THERE IS NO ACCELERATION • ISOBARS ARE STRAIGHT AND PARALLEL • CF AND PGF ARE IN BALLAN

Winds in the Upper Atmosphere: — H L PGF CF Balance!PG

Geostrophic (Earth turning) Wind • Why winds aloft more or less parallel to the isobars or contour lines? • Consider air at 1 -km above the earth’s surface; • the PGE acts on the air accelerating it northward toward lower pressure- — when the air begins to move, • CF deflects the air toward its right , curving its path —as the speed of air increases (2, 3, 4) • CF increases bending the wind more; CF increases with latitude ; • at point 5, net force = 0 — wind flows in a straight path, parallel to the isobars at a constant speed – This flow of air is called Geostrophic Wind • Coriolis acceleration = 2 w x v = 2 wv cos latitude; w: angular velocity of rotation of earth; v: vertical velocity of air mass)

At 1 -km above earth’s surface, the isobaric lines are evenly spaced (constant PGF); parcel of air left at 1; two forces act-PGF and CF ; CF increases with lat i.

Isobars and contours on a upper-level chart; when widely spread, flow is weak ; when narrowly spaced, flow is stronger ; increase in winds results in a stronger CF which balances larger PG

GEOSTROPHIC WIND • When the flow is purely geostrophic, the isobars (or contour lines) are straight and evenly spaced and wind speed is constant; • the speed of geostrophic wind is directly related to the pressure gradient

The Geostrophic Wind Above the atmospheric boundary layer (more than about 1 km above ground level) there is almost no friction , so low pressure is almost exactly 90 to the left of the wind. If, the wind also flows in a straight line at a steady pace there is no net acceleration and it is called the GEOSTROPHİC WİND. The geostrophic wind blows parallel to the isobars with low pressure exactly 90° to its left ( right ) in the North ( South ) Hemisphere. Only two forces act on the geostrophic wind. THE PRESSURE GRADİENT FORCE pulls wind toward LOW PRESSURE. It is exactly cancelled by the CORİOLİS FORCE , which pulls the wind to its right. The geostrophic wind represents a perfect balance between the pressure gradient force and the Coriolis force. The GEOSTROPHİC WİND SPEED is inversely proportional to the DİSTANCE BETWEEN İSOBARS

GEOSTROPHIC WIN

GRADIENT WIND • INTRODUCTİON TO GRADİENT FLOW • Recall that the flow is GEOSTROPHİC when the PGF and the CF are in balance • this occurs when the isobars (height lines) are relatively STRAİGHT • what about the case when the isobars have CURVATURE , as around highs and lows? ? • when there is CURVATURE in the flow, • we must also consider the CENTRIPETAL force acting on a parcel •

GRADIENT WIND • Gradient flow around highs and lows • Hence, the gradient wind is due to a combination of the : • PRESSURE GRADİENT FORCE • CORİOLİS FORCE • CENTRİPETAL FOR

GRADYAN RÜZGAR- GRADIENT WIND • GRADIENT WIND: THE CURVED AIRFLOW PATTERN AROUND A PRESSURE CENTER RESULTING FROM A BALANCE AMONG PRESSURE-GRADIENT FORCE (PGF), CORIOLIS FORCE (CF) AND CENTRIPEDAL FOR

GRADIENT WIN

GRADIENT WIN

GRADIENT WIN

Geostrophic Versus Gradient Winds In reality , PGF is rarely uniform since height contours curve and vary in distance Geostrophic flow assumption is too simplistic wind still flows parallel to contours HOWEVER it is continuously changing direction (and thus experiencing acceleration) for isobar-parallel flow to occur an imbalance must exist between PGF and CE Gradient Flow Ideal Reality

CENTRIFUGAL AND CENRIPETAL FORCE Recall from physics that if you attach a string to a ball and swing it in a circular manner, then the force that is required to keep the ball moving in the circular path is called the CENTRİPETAL FORCE the centripetal force is directed İNWARD, towards the axis of rotation as you swing the ball with the string, you feel the string tug on you hand. . , this is called the centripetal force and is equal and opposite to the CENTRİFUGAL FORCE. . .

SİKLOSTROFİK RÜZGAR -CYCLOSTROPHIC WIND • EKVATOR CİVARINDA CORİOLİS KUVVET MİNUMUM VE MERKEZCİL KUVVET HEMEN BASINÇ GRADYANI KUVVETİ KADAR OLDUĞUNDAN RÜZGARLAR, ŞİDDETLİ TROPİKAL FIRTINALAR ŞEKLİNDE ESEBİLİR. BU RÜZGARA SİKLOSTROFİK RÜZGAR DENİR. • CORIOLIS FORCE IS MINUMUM AND PRESSURE GRADIENT FORCE IS EQUAL TO CENTRIPETAL FORCE AROUND THE EQUATOR. • THEREFORE WINDS AROUND EQUATOR MAY BLOW AS INTENSE TROPHICAL STORMS. • THEY ARE CALLED CYCLOSTROPHIC WIND. CYCLOSTROPHİC BALANCE — BALANCE BETWEEN PGF AND THE CENTRİFUGAL FORCE — In a small area and short time span the Coriolis force is not that important

Cyclostrophic Balance L Centrifugal force Pressure gradient balances the centrifugal force. Occurs where flow is on a small enough scale where the Coriolis force becomes negligible. PGF + centripetal force = 0 OR PGF = Centrifugal force

In that case, the PRESSURE GRADİENT FORCE would balance the CENTRİPETAL FORCE. Because the Coriolis force is not involved in cyclostrophic balance, there is no preference for winds to rotate counterclockwise around a small, short-lived low such as a tornado. CYCLOSTROPHIC WIND CYCLO meaning «CYCLONE» or low-pressure system and STROPHİC meaning «TURNİNG. » In other words, this balance describes situations in which the TURNİNG OF THE WİND , not the Earth , İS THE DOMİNANT EFFECT. A cyclostrophic circulation can result in a brief but rapid drop in surface pressure due to the rising motions these circulations can produce.

YÜZEY RÜZGARLARI— SURFACE WIND • FRICTION IS EFFECTIVE ONLY WITHIN THE FIRST FEW KM. OF EARTH’S SURFACE BY DECREASING THE WIND SPEED. • WIND BLOWS FROM HP TOWARD LP BY MAKING α ANGLE WITH ISOBARS AT THE SURFACE. • α IS CREATED BY FRICTION. AT UPPER LEVELS WITHOUT FRICTIN WIND BLOWS PARELLEL TO THE ISOBARS.

RÜZGARLAR- WINDS • THE ANGLE BETWEEN WINDS AND ISOBARS IS RELATED TO THE SURFACE STRUCTURE. MOUNTANEOUS SURFACE CREATE 35 -40 DEGREES ANGLE, FLAT SURFACE CREATE 10 — 15 DEGREES ANGLE. • THE AVERAGE ANGLE IS ASSUMED AS 30 DEGREES • IF WIND SPEED IS HIGH THEN ANGLE IS LESS AND IF WIND SPEED LOW THEN ANGLE IS BIG

WINDS NEAR THE SURFACE FRICTION is important for air within ~1. 5 km of the surface (the so-called planetary boundary layer). FRICTION varies with SURFACE TEXTURE, WIND SPEED, TIME OF DAY/YEAR AND ATMOSPHERIC CONDITIONS. Friction above 1. 5 km is often small (often called the free atmosphere ), except over regions with storms and gravity waves. FRICTION slows down WIND SPEED and reduces CORIOLIS DEFLECTION FRICTION causes air CONVERGING INTO LOW PRESSURE AREAS, but DIVERGING AWAY FROM HIGH PRESSURE AREASThe third term (friction) must be considered: FFCEPGF t V

FRICTION EFFECT OF FRICTION ON WINDS The last force we must consider is FRICTION Q : Where will friction have the greatest impact on the winds? ? ? ANSWER NEAR THE EARTH SURFACE Hence, above approximately 850 mb , the flow is either in geostrophic or gradient wind balance from the surface to about 1 -1. 5 km AG, we must include the effect of friction and therefore, the flow is no longer in geostrophic or gradient wind balance. . .

Since FRICTION acts in the opposite direction of the wind , it SLOWS THE WIND Change in speed CHANGE İN MAGNİTUDE OF THE CORİOLİS FORCE Friction + Coriolis force ~ PGF no longer geostrophic balance and WINDS CAN CROSS THE ISOBARS FRICTION

Effect of frictional force Upper air w/out Friction (geostrophic balance) Near surface w/ Friction Counterclockwise in NH (opposite in SH)characterized by ascending/diverging air which cools to form clouds/precipitation. Clockwise airflow in NH (opposite in SH) Characterized by descending/converging air which warms creating clear skies

YÜZEY RÜZGARLARI- SURFACE WIN

YÜZEY RÜZGARLARI- SURFACE WIN

FRICTION • Less Friction • Much Friction

BACKING/VEERING BACKING • WIND SHIFT IN A COUNTERCLOCKWISE DIRECTION, SUCH AS A SHIFT FROM EAST TO NORTH AND THEN NORTH WEST. VEERING WIND SHIFT IN A CLOCKWISE DIRECTION, SUCH AS A SHIFT FROM EAST TO SOUTH THEN SOUTH WEST.

BUYS BALLOT KANUNU-LAW • WITH YOUR BACK TO THE WIND IN THE NORTERN HEMISPHERE , HP WILL BE YOUR RIGHT SIDE AND LP IS YOUR LEFT SIDE . THE REVERSE IS TRUE IN THE SOUTERN HEMİSPHERE IN HIGH ALTITUDES. • AT THE SURFACE , WHEN YOU GET THE WIND FROM YOUR BEHIND, YOU HAVE TO TURN 30 DEGREES TO YOUR RIGHT THEN THE REST IS THE SAME AS HIGHER ALTS. IN SOUTHERN HEMS. YOU HAVE TO TURN 30 DEG. TO YOUR LEFT AND THEN YOUR LEFT SIDE IS HP

BUYS BALLOT KANUNU-LAW

TRUE AND APPARENT WIND • Definition of APPARENT WİND • T he Apparent wind is the wind experienced by an observer in motion and is the relative velocity of the wind in relation to the observer. • Apparent wind velocity is the vector sum of the true wind and the headwind an object would experience in still air. The headwind velocity in still air is inverse of the object’s velocity, therefore the apparent wind can also be defined as a vector subtraction: the Velocity of the wind minus the Velocity of the object. • A simple example • Suppose you are riding a bicycle on a day when there is no wind. Although the wind speed is zero (people sitting still feel no breeze), you will feel a breeze on the bicycle due to the fact that you are moving through the air. This is the apparent wind. On the windless day, the apparent wind will always be directly in front and equal in speed to the speed of the bicycle. • Now suppose there is a 5 mph wind coming directly from the north. If you pedal at 10 mph due north, you will feel an apparent wind of 15 mph from the north. But if you pedal 10 mph due south, you will feel an apparent wind of 5 mph from the south. The apparent wind is not only different in speed than the true wind (except when you are standing still), but may also be different in direction.

APPARENT WIND • In sailing , • the apparent wind is the actual flow of air acting upon a sail. It is the wind as it appears to the sailor on a moving vessel. It differs in speed and direction from the true wind that is experienced by a stationary observer. • In nautical terminology , these properties of the apparent wind are normally expressed in knots and degrees. On boats, apparent wind is measured (see «Instruments» below) or «felt on face / skin» if on a dinghy or looking at any telltales or wind indicators on-board. TRUE WİND NEEDS TO BE CALCULATED OR STOP THE BOAT. • The apparent wind on-board (a boat) is often quoted as a speed measured by a masthead transducer containing an anemometer and wind vane that measures wind speed in knots and wind direction in degrees relative to the heading of the boat. Modern instrumentation calculate the true wind velocity when the apparent wind and boat velocity & direction are input.

Winds that blow over short distances and are caused by unequal heating of Earth’s surface within a small area. LOCAL WINDS

LOCAL WINDS Types: – Land Breezes – Sea Breezes – Mountain Breezes – Valley Breezes Local winds can move from any direction but only move short distances. They are formed from the uneven heating of the Earth and pressure differences

Sea Breeze – a wind that blows from an ocean or lake onto land. Land Breeze – the flow of air from land to a body of water.

LAND SEA BREEZES Sea Breeze : Wind off the ocean during the day time (colder temps/higher pressure over the ocean) Land Breeze : Wind off the land during the night time (colder temps/higher pressure over the land)

UNEVEN HEATING OF ADJACENT LAND & SEA AREAS OVER THE 24 HOURS OF THE DAY NOTE THAT AIR TEMPERATURE OVER LAND & SEA IS ROUGHLY THE SAME AT SUNRISE AND SUNSET • DAYTIME: – SOLAR RADIATION HEATS THE LAND TO A DEPTH OF A FEW cm WITH LARGE TEMPERATURE RISE – SOLAR RADIATION HEATS THE SEA TO A DEPTH OF SOME 10 -30 m WITH A VERY SMALL SEA TEMPERATURE RISE • NIGHTTIME: – RADIATION COOLING CREATE BIG TEMPERATURE DROP FROM THE TOP FEW cm OF THE LAND SURFACE – RADIATION COOLING CREATE MİNOR TEMPERATURE DROP FROM THE SEA SURFACE, CAUSES OF LAND SEA BREEZES

Sea Breeze Location: air moves from the sea to the land Facts: (During the day) – Air over water is cooler & creates high pressure. – Cool, dense air moves toward land, creating a sea breeze. – Air over land is warmer, so the warm air rises, creating low pressure over land.

SEA BREEZE (FROM THE SEA) • DAY TIME SUN HEATS LAND • UPPER AIR FLOW FROM LAND TO SEA • LOWER AIR FLOW FROM SEA TO LAND : A SEA BREEZ

Land Breeze Location: air moves from the land to the sea Facts: (During the night) – Air over land is cooler & creates high pressure. – Cool air moves toward the sea, creating a land breeze. – Air over the sea is warmer, so it rises creating low pressure.

SEA AND LAND BREEZES

SEA AND LAND BREEZES

EFFECT OF TOPOGRAPHY • TOPOGRAPHY CAN SIGNIFICANTLY MODIFY THE DIRECTION AND FORCE OF THE SEA BREEZE: – HIGH LAND ADJACENT TO THE COAST LINE MAY DEFLECT WIND PARALLEL TO THE COAST – INLETS WITH HIGH SIDES WILL CAUSE A FUNNELLING EFFECT: • DEFLECT DIRECTION • INCREASE WIND SPEED OVER THE WATER

MOUNTAIN AND VALLEY BREEZES

Mountain Breeze Location: cool air sinks from the mountain top into the valley below Facts: – Mountain tops cool faster than valleys at night. – Cold air is dense (heavier) so it sinks from the mountain tops into the valleys below creating a mountain breeze.

Animation of mountain breezes

Valley Breeze Location: warm air moves up the mountain from the valley below Facts: – The sun heats the valley floor & warms the air above it. – The warm air rises creating a valley breeze.

Animation of valley breeze

MOUNTAIN AND VALLEY BREEZES

KATABATIC WINDS • Katabatic wind (from the Greek: katabaino — to go down ) is the generic term for downslope winds flowing from high elevations of mountains, plateaus, and hills down their slopes to the valleys or planes below. Katabatic winds exist in many parts of the World and there are many different names for katabatic winds depending where they are located and how they are formed. Warm, dry katabatic winds occur on the lee side of a mountain range situated in the path of a depression. Examples for these descending, adiabatically warmed katabatic winds are the Foehn winds. Cold and usually dry katabatic winds , like the Bora , result from the downslope gravity flow of cold, dense air. Katabatic flows slumping down from uplands or mountains may be funneled and strengthened by the landscape and are then known as mountain gap wind such as the Santa Ana , mountain breeze or drainage wind. The gentler katabatic flows of hill slopes produce frost hollows. Mountain breezes are part of a local wind system. When the mountainside is heated by the Sun the mountain breeze will break down, reverse and blowing upslope. These winds are known as valley wind or anabatic wind.

KATABATIC (DOWN) SLOPE WINDS • AT NIGHT • UNEQUAL COOLING TAKES PLACE ON SLOPES • COLD DENSE AIR ON HIGHER GROUND – HIGHER PRESSURE ON UPPER SLOPES – RELATIVELY LOW PRESSURE ON LOWER SLOPES • WIND FLOWS DOWN SLOP

ANABATIC (UP SLOPE) WINDS • WARM SUNNY DAYS • HEATED AIR IN A VALLEY LATERALLY CONSTRICTED IN COMPARISON TO ASSOCIATED PLAIN • AIR HAS TO EXPAND VERTICALLY: – LOWERED PRESSURE IN VALLEY – RELATIVELY HIGH PRESSURE ON ASSOCIATED PLAIN • WIND FLOWS UP THE VALLEY (VALLEY WIND) • LIGHT WIND, WEAK REGIONAL PRESSURE GRADIENT REQUIRED TO ENHAN

ANABATIC (UP SLOPE) WINDS

ANABATIC (UP SLOPE) WINDS

WHAT IS FOEHN WINDS www. hko. gov. • As the name implies, FOEHN winds are DRY AND HOT. They descend along the LEESİDE of the mountains, and are special to mountainous regions.

Fohn (Chinook) Winds • CAUSED BY UNEQUAL HEATING AND WARMING OF STABLE AIR WHICH IS FORCED TO FLOW OVER A MOUNTAIN BARRIER BY REGIONAL PRESSURE GRADIENT • FOUND ON LEE SIDE OF MOUNTAIN RANGE • STRONG, GUSTY, WARM AND DRY WIN

What causes foehn wind www. hko. gov. Foehn winds are caused by the SUBSİDENCE OF MOİST AİR AFTER PASSİNG A HİGH MOUNTAİN. The air is forced to move upslope when encounters a mountain barrier. As the temperature decreases with height, the moist air will become SATURATED and CONDENSE TO FORM CLOUDS AND RAİN when it rises to a certain height. The amount of water vapour that remains in the air therefore decreases. After passing the ridge and descending along the leeside of the mountain, THE AİR BECOMES WARMER. Temperature of drier air will rise even faster. This results in DRY AND HOT WİNDS.

FOHN WINDS

WHAT ARE THE EFFECTS OF FOEHN WINDS www. hko. gov. • Apart from bringing warmer and drier weather , Foehn winds can cause serious natural disasters. • They bring droughts, • Dry up plants and farmlands , • Exacerbate forest fires. • They also melt snow, causing avalanche and floods

Monsoons Arabic word “mausim” means“season Sea and land breezes over a large region that change direction with the season. Monsoons: A regular and extreme weather change caused by the shift of wind and pressure belts, which is directly related to the changes in seasons

MONSOONS • LARGE LAND MASSES BECOME HEATED IN SUMMER AND, LOW PRESSURE OVER THE LAND HIGH OVER THE SEA. • THE REVERSE TAKES PLACE IN WINTER. THE RESULTING WIND CIRCULATION TEND TO PERSIST THROUGHOUT THEIR PARTICULAR SEASONS AND ARE CALLED MONSOON. • THE MOST DEVELOPED MONSOON OCCUR OVER SOUTHERN AND EASTHERN ASIA. THEY OCCUR TO A LESSER DEGREE IN WEST AFRICA, AMERICA AND AUSTRALIA.

LOCAL WINDS IN MEDITERRANEAN

LOCAL WINDS lise Southern France Bora Eastern Adriatic Crachin China Sea Etesians Aegean Sea Fohn Swiss Alps. The same effect occurs in most parts of the wortd Haar Eastern Scotland eastern parts of England Harmattan North-west Africa Kaus Persian Gulf Khamsin Egypt North African coast Kharif Gulf of Aden teste Madeira and North Africa levanter Strait of Gibraltar Leveche South-east coast of Spain Libeccio Northern Corsica Maestro Adriatic Sea Marin Gulf of Lyons Mistral North-west coast of Mediterranean Norther Gulf of Mexico Pampero Rio de la Plata area Scirocco Mediterranean Shamal Persian Gulf and ·Gutf of Oman Solano Strait of Gibraltar Southerly buster South and. S. outh-east coast of Australia $umatras Malacca Strait Tramontana West coast of Italy and Corsica. Vendava. Les East coast of Spain and Gibraltar Strait , :

MEASUREMENT OF WIND SPEED AND DIRECTION WIND DIRECTION IS MEASURED BY WIND VANE OR WIND SUCK(CONE SHAPED BAG) WIND SPEED IS MEASURED BY ANEMOMETER (OR CUP ANEMOMETER)

RÜZGAR ŞİDDETİ/ WIND SPEED • WIND SPEED IS INTERNATIONALLY DESIGNATED WITH BEAUFORT SCALE • FROM 0 TO 12 BEAUFORT

BEAUFORT SKALASI

BEAUFORT SKALASI

BEAUFORT SKALASI

• Practical way to convert Beauforth to Knots. • Beau. Kts. • 1, 2, 3 x 3 =. . • 4, 5, 6, 7 x 4 =. . • 8, 9, 10, 11, 12 x 5=. .

BEAUFORT SCAL

BEAUFORT SCALE • Practical way to convert Beauforth to Knots. • Beau. Kts. • 1, 2, 3 x 3 =. . • 4, 5, 6, 7 x 4 =. . • 8, 9, 10, 11, 12 x 5=. .

AIR MASSES What’s the definition? A large body of air with similar characteristics throughout

AIR MASS

SOURCE OF AIR MASS

AIR MASS • Air masses originate in source regions • SOURCE REGIONS : Anticyclone belts north and south of the westerlies. • Mutual specialty(characteristic) of these areas are; – flat, uniform bodies – light winds , clear weather (High Presure belt properties) – Air masses get their characteristics based on Where they form

World Air Mass Source Regions

GEOGRAPHICAL CLASSIFICATION OF AIR MASSES BASED ON SOURCE REGION

AIR MASS

AIR MASS

AIR MASS

AIR MASS

CLASSIFICATION OF AIR MASS AIR MASS CLASSIFICATION • 4 general categories according to GEOGRAPHIC POSITION • ARCTIC (A) • POLAR (P) • TROPICAL (T) • EQUATORIAL( E) • • CATEGORIES BASED ON SOURCE REGION m = MARITIME , c = CONTINENTAL • THERMODYNAMİC CLASSİFİCATİON • W =WARM, • k = KALT (COLD) c. Pw- c. Pk- m. Pw- m. Pk- c. Aw- c. Ak m. Aw- m. Ak- c. Tw c. Tk- m. Tw- m. Tk NOTE : extremely cold c. P air is sometimes denoted at c. A extremely hot, humid m. T air is sometime denoted by m. E • GEOGRAPHIC CLASSIFICATION • THERMODYNAMIC CLASSIFICATION

CHARACTERISTICS OF AIR MASS

AIR MASS

The abbreviations used to classify air masses use the following letters: c, m, T, P, and A. For each letter, describe its property: Word Means c m T P A continental dry maritime moist Tropical warm Polar cold Arctic very cold

• Moisture content is noted by the first letter. m – maritime – wet c – continental – dry • Temperature is noted by the second letter. P – polar – cool T – tropical — warm Air masses

• m. P- maritime polar air mass • c. P – continental polar air mass • m. T – maritime tropical air mass • c. T – continental tropical air mass Air Masses

What would their characteristics be? m. T c. P warm and moist cold and dry

GEOGRAPHICAL CLASSIFICATION OF AIR MASSES BASED ON SOURCE REGION

TERMODYNAMIC CLASSIFICATION OF AIR MASSES • THERMODYNAMIC CLASSIFICATION • WARM AIR. (W) WARM • THE AIR MASS WHICH HEATS THE SURROUNDING IS CALLED WARM AIR. ITS TEMPERATURE IS HIGHER THAN THE TEMPERATURE OF THE SURFACE BELOW IT • COLD AIR. (K) KALT • THE AIR MASS WHICH COOLS THE SURROUNDING IS CALLED COLD AIR. ITS TEMPERATURE IS LOWER THAN THE TEMPERATURE OF THE SURFACE BELOW IT

THERMODYNAMIC-GEOGRAPHİC AND SOURCE CLASSIFICATION OF AIR MASSES

How do air masses move? Prevailing westerlies push air masses from west to east.

AIR MASS

AIR MASS WEATHER TYPES

AIR MASS WEATHER TYPES

SUPERIOR AIR MASS OCCURS ONLY BY THE SUBSIDENCE. • THEY HAVE NO DIRECT INFLUENCE FROM THE SURFACE. • THEY EXIST OVER THE TEMPERATURE INVERSION. • THEY ARE EXTREMELY DRY. • THEY EXIST SOUTH OF PREVAILING WESTERLIES AND NORTH OF SUBTROPHICAL CYCLONS.

MODIFICATION OF AIR MASSES • AIR MASS MAY BE MODIFIED IN THREE WAYS WHEN IT LEAVES FROM SOURCE REGION • A. THERMODYNAMIC MODIFICATION • B. MECHANICAL MODIFICATION C. MODIFICATION BY TURBULAN

TERMODYNAMIC MODIFICATION • MOD. BY HEATING BELOW • MOD BY COOLING BELOW • MOD BY ADDING WATER VAPOR(VAPORIZATION) • MOD BY LOOSING WATER VAPOR(CONDENSATION )

MECHANIC MODIFICATION OF AIR MASS BY THE EFFECT OF CONVERGENCE OR DIVERGENCE • BY SUBSIDENCE: • SUBSIDING OVER A COLD AIR MASS(DIVERGENCE AT SRF. ) • BY UPRISING • UPRISING OVER A COLD AIR MASS(CONVERGENC E AT SRF. ) • BY ADVECTION

MODIFICATION OF AIR MASS BY TURBULANCE HEAT EXCHANGE BY RADIATION BETWEEN SURFACE AND ATMOSPHERE OCCUR IN THE FIRST 50 M. WHEREAS HEAT EXCHANGE BY TURBULANCE IS EFFECTIVE UP TO HIGH LEVEL. WITH THIS WAY THERE IS HEAT EXCHANGE BY WAY OF MASS TRANSPORT

SOME CHARACTERISTICS OF COLD AND WARM AIR MASS STABILITY TURBULENCE VISIBILITY CLOUDS PRECIPITATION COLD INSTABLE YES GOOD CU THUNDER-SHOWER WARM STABLE CONT. WIND BAD ST DRIZZL

Analyzing Air Masses ► An air mass is most easily identified by comparing it to other air masses. ► Air masses can be modified with time , most notably by days of sunshine or lack thereof. ► Fronts are the dividing line between air masses so understanding air masses, means understanding where fronts are located.

FRONTS A DISCONTINUITY ZONE EXISTS WHEN TWO DIFFERENT AIR MASS COME TOGETHER. THIS DISCONTINUITY ZONE IS CALLED FRONT SURFACE INTERSECTION BETWEEN FRONT SURFACE AND THE EARTH’S SURFACE IS CALLED FRONT

What is a Front? ► Definition: A narrow transition zone, or boundary, between disparate synoptic scale air masses whose primary discontinuity is density. ► Commonly associated with. . Moisture gradient Temperature gradient Wind shift Pressure Trough Convergent boundary

FRONTS • A weather front is a boundary separating two masses of air of different densities , and is the principal cause of meteorological phenomena. In surface weather analyses , fronts are depicted using various colored lines and symbols, depending on the type of front. • The air masses separated by a front usually differ in temperature and humidity. • COLD FRONTS may feature narrow bands of thunderstorms and severe weather , and may on occasion be preceded by squall lines or dry lines. • WARM FRONTS are usually preceded by stratiform precipitation and fog. The weather usually clears quickly after a front’s passage. Some fronts produce no precipitation and little cloudiness, although there is invariably a wind shift

Fronts When air masses meet is a front, the collision often causes storms and weather changes. A front may be 15 to 200 kilometers wide and extend as much as 10 kilometers up to the troposphere. The kind of front that develops depends on the characteristics of the air masses and how they move.

RULES FOR FINDING FRONTS ► LOOK FOR A STRONG TEMPERATURE GRADİENT. The front is located on the warm side of the sharpest gradient. ► Likewise, LOOK FOR A STRONG DEWPOİNT GRADİENT. The front is located on the moist side of the sharpest gradient. ► Generally found in a pressure trough – look for three hour pressure changes. FRONTS WİLL SHOW a decrease in pressure followed by a rapid increase in pressure AFTER THE FRONTAL PASSAGE. ► Look for a sharp CHANGE İN WİND DİRECTİON. A cyclonic shear in the wind direction usually indicates a frontal passage ► CHECK WEATHER AND CLOUD PATTERNS that are usually associated with different kinds of fronts

CEPHE KARAKTERİSTİKLERİ FEATURES OF THE FRONTS • FRONTS OCCUR LP AREAS OR TROUGHS. • PRESSURE DROPS WHEN FRONTS ARE APPROACHING AND AFTER THE PASSAGE PRESSURE RISES • FRONTS EXIST BETWEEN TWO DIFFERENT AIR MASSES WHICH HAVE DIFFERENT TEMPERATURE • WARM AIR IS ALWAYS OVER THE COLD AIR AT THE FRONTS • WIND AT NORTHERN HEMİSPHERE BLOW COUNTER CLOCKWISE WHILE FRONT PASSING • THERE IS ALWAYS AN ANGLE BETWEEN FRONT SURFACES AND HORIZONTAL PLAN

CEPHELERİN TERMİK YAPISI THERMAL STRUCTURE OF THE FRONT • INTENSITY(WEAK/STRONG) OF THE FRONT IS RELATED WITH THERMAL STRUCTURE • WEAK FRONTS HAVE WEAK TEMPERATURE GRADIENT, • STRONG FRONTS HAVE BOTH BIG VERTICAL AND HORIZONTAL TEMPERATURE GRADIENT • THE ACTIVITY OF A FRONT IS RELATED WITH THE CLOUDINESS AND THE WIDTH OF THE PRECIPITATION AREA and related with the vertical velocıty and stability conditions • STRONG FRONT NOT ALWAYS CREATE AN INTENSIVE AIR ACTIVITIES

CEPHELERİN NEM DAĞILIŞI HUMIDITY DISTRIBUTION OF FRONTS • IF WARM AIR IS RISING OVER THE COLD AIR RELATIVE HUMIDITY IN THE WARM AIR IS ALMOST 100% • SPECIFIC HUMIDITY IS MAXIMUM OVER THE FRONT SUR

CEPHELERDE RÜZGARIN YÜKSEKLİKLE DEĞİŞİMİ VERTICALLY MODIFICATION OF THE WIND AT THE FRONT • WIND TURNS CYCLONICALLY IN THE TRANSITION FROM COLD AIR TO WARM AIR IN VERTICAL OR HORIZONTAL DIRECTION AT THE SURFACE OF THE COLD FRONT. • UNDER THE SAME CONDITION AT THE WARM FRONT AND SURFACE OF THE WARM FRONTS IT IS ANTICYCLONI

KİNEMATİK SINIR KOŞULU KNEMATIC BOUNDRY CONDITION KNEMATIC BOUNDARY CONDITION THIS CONDITION STATES THAT WIND COMPONENTS WHICH ARE PERPENDICULAR TO THE SURFACE OF THE FRONT MUST BE EQUAL IN EACH AIR MASS. OTHERWISE , A GAP EXISTS OR FRONT DIMINISHES. A SURFACE OF FRONT MOVES WITH THE WIND COMPONENT WHICH IS PERPENDICULAR TO IT

CLASSIFICATION OF THE FRONTS GEOGRAPHIC CLASSIFICATION • ARCTIC FRONT • MARITIME ARCTIC • CONTINENTAL ARCTIC • POLAR FRONT • INTERTROPHICAL CONVERGENCE ZONE ( ITCZ) • MEDITERRANEAN FRONT KNEMATIC CLASSIFICATION • COLD FRONT • WARM FRONT • STATIONARY FRONT OCCLUDED FRONT • COLD OCCLUSION • WARM OCCLUSION • NEUTRAL OCCLUSION

GEOGRAPHIC CLASSIFICATION

INTERTROPHICAL FRONT( ITCZ ) • THE TEMPERATURES OF THE BOTH SIDE OF THE EQUATOR ARE ALMOST THE SAME. • THEREFORE ITCZ IS NOT A REAL FRONT • IT IS EXISTED WHEN IT MOVES NORTH BUT DIMINISHES OR EVEN LOST WHEN IT MOVES TOWARD THE EQUATOR

FRONTS

TYPES OF FRONTS(THERMODYNAMIC) ► COLD Noted by cold air advancing and displacing warmer air that exists. ► WARM Noted by cold air retreating from an area. ► STATİONARY While differing air masses exist along a boundary, little movement is analyzed of the air masses. ► OCCLUDED A complicated process where the surface low becomes completely surrounded by cooler/cold air. Occlusion processes can be a “cool type” or “cold type” (more later. )

• A front is a boundary between air masses. • Four types of fronts and map symbols 1. Cold front 2. Warm front 3. Occluded front 4. Stationary front Fronts

Cold Front ► Marked on a map with a blue line and blue triangles pointing towards the warm air. ► Slopes of 1/50 to 1/150 ► Associated with cumulus & cumulonimbus clouds ahead of the front in the warm air, producing showers and thunderstorms.

COLD FRONT CROSS SECTION • COLD FRONT-CROSS SECTİON • warm air ahead of front is lifted up and over • can get intense showers/thunderstorms at frontal boundary • Cs and Ci clouds are blown ahead of the front by upper level winds • cloud base is generally lower behind the front. . why? ? ? • further behind the front, the air is quite dry, few clouds • steep frontal boundary, slopes backward into the cold air • frontal speed averages 15 -25 knots • temperature and wind profiles on either side of cold front

Cold Front ► Simple 3 -D idea: http: //www. physicalgeography. net/fundamentals/7 r. html

Cold Fronts Cold air is dense and tends to sink. Warm air is less dense and tends to rise. When a moving cold air mass runs into a slowly moving warm air mass, the denser cold air slides under the warmer air. Warm air can hold more water vapor than cool air. If there is a lot of water vapor in the warm air heavy rain or snow may fall. Cold fronts move quickly so they can cause weather changes. After a cold front passes, cool, dry air moves in.

COLD FRONT • Cold air mass meets a warm air mass and pushes the warm air mass out of its way. • Bring thunderstorms, rain or snow. • Most tornadoes develop from • thunderstorms on the edge of a cold front. • Cold front followed by cooler drier air.

Cloud types with a cold front These cloud types usually occur ahead of a cold front. In which order would you expect them to occur as a front approaches? Cirrus Cumulonimbus Altocumulus. Stratocumulus

Cold Front http: //www. free-online-private-pilot-ground-school. com/images/cold-front. gif

Cold Front :

Cold Front Warm air rising causes violent thunderstorms & hail forms cumulonimbus clouds Clear cool days follow Cold Air Warm Air

THE COLD FRONT The cold front rapidly undercuts the air in the warm sector, making it rise very quickly. The Warm Sector (warm, moist air)T he Cold Sector ( cold dense air )

Very tall clouds are formed by the rapidly rising air. These are called CUMULONIMBUS. The Warm Sector (warm, moist air)CUMULONIMBUS give very heavy showers, sometimes with thunder and lightning. PRECIPITATION AT THE COLD FRONT

SOĞUK CEPHE- COLD FRONT

COLD FRONT PASSAG

Warm Front High level clouds are first indicators of a warm front forms nimbostratus clouds Causes steady rain or showers Followed by hot humid days

Warm Front ► Marked on a map by a red line with red semi-circles pointed towards the cool air (in the direction the warm air is retreating to. ) ► Slope ranges from 1/100 to 1/300. ► Generally associated with stratus type clouds, overcast skies, fog, and general rain or snow.

WARM FRONT • Warm air mass meets a cold air mass and pushes the cold air mass out of the way. • Brings drizzly precipitation. • Followed by clear warm weather.

Warm Fronts A moving warm air mass collides with a slowly moving cold air mass. If the warm air is humid showers and light rain might fall along the front where the warm and cold air meet. If the warm air is dry scattered clouds may form. After a warm front passes through an area the weather is likely to be warm and humid. Winter warm fronts bring snow.

Warm Front http: //www. free-online-private-pilot-ground-school. com/images/warm-front. gif

Warm Front :

Warm fronts Occurs when warm air advances over colder air Warm front symbol

Cloud types with a warm front Cirrus Nimbostratus Altostratus Cirrostratus. These cloud types usually occur ahead of a warm front. In which order would you expect them to occur as a front approaches?

WARM FRONT PASSAG

OCCLUDED FRONT

WHAT HAPPENS AT THE WARM FRONT? Warm air begins to rise over the cooler air As this air rises, it begins to cool Cool air can hold less water vapour than warm air Water vapour begins to condense into water droplets Water droplets begin to form clouds The first – and highest – type of cloud to form along the warm front is called Cirrus

As the warm air rises, it cools. Dense cool air. Warm air is forced to rise over denser, cool air. Water vapour condenses and forms clouds These high-level wispy clouds are called CIRRUSAIR RISING ALONG THE WARM FRONT (1)

Dense cool air. More moist air rises and cools Clouds form lower down, and give prolonged rain CIRRUSPRECIPITATION AT THE WARM FRONT These are CUMULUS

CUMULUS CLOUDS

Dense cool air. More moist air rises over the cooler air. As it does so it cools. CIRRUS are very high and wispy. They are usually the first clouds we see as the warm front approaches. THE WARM FRONT — SUMMARY CUMULUS clouds bring prolonged rain at the warm front. Warm Front

AN APPROACHING WARM FRONT CIRRUS CUMULUS

CUMULONIMBUS CLOUDS

IN THE WARM SECTOR Warm, moist winds blow from the South West Air is forced to rise over cooler air Condensation occurs, and forms Stratus clouds Showers are common. The sky is very overcast

Dense cool air. THE WARM SECTORWarm front Warm, moist air in the warm sector is rising. Cold Sect or cold dense air

Dense cool air. CLOUD & PRECIPITATION IN THE WARM SECTORW A R M F R O N T Warm, moist air in the warm sector is rising. The clouds formed here are mostly Stratus are flat layer clouds. They give showers. STRATUS Cold Sect or cold dense air

CLOUD & PRECIPITATION – SUMMARY 1 Dense cool air. STRATUS CIRRUS CUMULUSCUMULONIMBU SW A R M F R O N T PERSISTENT RAINLIGHT SHOWERSHEAVY SHOWERSCold Sect or cold dense air

Stationary Fronts Sometimes cold and warm air masses meet but neither one has enough force to move. Where the warm and cold air meet, water vapor in the warm air turns into rain, snow, fog, or clouds.

Stationary Front ► Marked by alternating blue lines & blue triangles (pointed in the direction of the warmer air) and red lines & red semi-circles (pointed in the direction of the cooler air) ► Usually noted as *quasi*-stationary as it is rarely ever completely stationary. It tends to meander a bit.

STATIONARY FRONT • Cold air meets warm air. • Not enough force to move either front. • Many days of cloudy, wet weather.

Stationary Front Cold air meets warm air and no movement occurs Rain can fall in the same place for days

Occluded Fronts A warm air mass is caught between two cooler air masses. As warm air cools and its water vapor condenses, the weather may turn cloudy, rainy, or snowy.

Occluded Front ► Marked by a purple line with alternating purple triangles and purple semi-circles, all pointing in the direction of the frontal movement. ► There are two general types of occlusions , warm- type and cold -type. Examples to follow.

OCLUDED FRONTS

OCLUDED FRONTS

Occluded Front ► Simple 3 -D idea: http: //www. physicalgeography. net/fundamentals/7 r. html

Occluded Front http: //www. free-online-private-pilot-ground-school. com/images/occluded-front. gif

Occluded Front Less violent weather than a cold front.

OCCLUSION FRONT • OCLUSION FRONT • A FRONT FORMED WHEN A COLD FRONT OVERTAKES A WARM FRONT. IT IS HAPPENED BECAUSE OF THE FASTER MOVEMENT OF COLD FRONT THAN WARM FRONT. THEY ARE 3 TYPES. • A. COLD TYPE OCCLUSION : A FRONT THAT FORMS WHEN THE AIR BEHIND THE COLD FRON T IS COLDER THAN THE AIR UNDERLYING THE WARM FRONT IT IS OVERTAKING • B. WARM TYPE OCCLUSION : A FRONT THAT FORMS WHEN THE AIR BEHIND THE COLD FRONT IS WARMER THAN THE AIR UNDERLYING THE WARM FRONT IT IS OVERTAKING • C. NEUTRAL OCCLUSION : IN THIS TYPE OF OCCLUSION PRACTICALLY THERE IS NO TEMPERATURE DIFFERENCE BETWEEN THE COLD AIR IN FRONT OF THE WARM FRONT AND COLD AIR BEHIND THE COLD FRONT

COLD OCCLUSION Cold Occlusion cold front «lifts» the warm front up and over the very cold air Associated weather is similar to a warm front as the occluded front approaches once the front has passed, the associated weather is similar to a cold front vertical structure is often difficult to observe

Warm Occlusion cold air behind cold front is not dense enough to lift cold air ahead of warm front cold front rides up and over the warm front upper-level cold front reached station before surface warm occlusion. WARM OCCLUSION

COLD-WARM OCCLUSION

OCCLUDED FRONT PASSAG

243 COLD FRONTS and OCCLUDED FRONTS generally move from WEST TO EAST, while WARM FRONTS POLEWARD. Because of the greater density of air in their wake, cold fronts and cold occlusions move faster than warm fronts and warm occlusions. Mountains and warm bodies of water can slow the movement of fronts. [2 ] When a front becomes stationary , and the density contrast across the frontal boundary vanishes , the front can degenerate into a line which separates regions of differing wind velocity , known as a shearline. This is most common over the open ocean.

NÖTR TİP OKLİZYON NEUTRAL OCCLUSION • NEUTRAL OCCLUSION. • IN THIS OCCLUSION PRACTICALLY THERE IS NO TEMPERATURE DIFFERENCE BETWEEN COLD AIR MASSES OF THE WARM AND COLD FRONTS

FRONTOGENESIS-FRONTOLYSIS FRONTOGENESIS • Fronts can strengthen with time – frontogenesis The formation of a new front or strenghtening of a former front • İNCREASE THE TEMPERATURE GRADİENT CAN LEAD THE FRONTOGENESİS FRONTOLYSIS • Fronts can weaken with time — frontolysis The weakenig or dying of a front

Frontogenesis and Frontolysis • Frontogenesis occurs when convergence and the temperature gradient correspond. – Convergence acts to increase the temperature gradient. – The stronger the temperature gradient being compressed, the stronger the frontogenesis. • Frontolysis occurs when divergence and the temperature gradient correspond. – Divergence acts to decrease temperature gradient. – The weaker the temperature gradient being decompressed, the stronger the frontolysis.

FRONTOLYSIS

FROTOGENESIS-FRONTOLYSIS IF WIND SPEED DECREASING FRONTOGENESIS IS POSSIBLE IF WIND SPEED INCREASING FROTOLYSIS IS POSSIBL

DYNAMIC BOUNDARY CONDITION • TEMPERATURE AND DENSITY AT THE FRONT CHANGE SHARPLY(THEY ARE NOT CONTINUOUS) • BUT PRESSURE AT THE FRONT IS CONTINUOUS. • THIS IS KNOWN AS DYNAMIC BOUNDARY CONDITION

SQUALL LINE LİNE SQUALL A very well marked. particularly active cold front in the form of a V-shaped trough. Its approach and passage are characterised by an arc or line of low black cloud (often ‘roll’ cloud) preceding the front. A sudden freshening and slight backing of the wind. followed by a veer of perhaps 90° or more as it passes, together with a hard squall or squalls, often heavy rain or hail with thunder and lightning ; it is also marked by a sudden fall in temperature. The barometer commences to rise rapidly, immediately the trough has passed, the wind moderates quickly and tends to back a little before settling to a steady direction. A line squall generally lasts for about 15 minutes and occasionally for half an hour.

ISOBARIC PATTERNS • DEPRESSION • ANTICYCLON • SECONDARY DEPRESSION • TROUGH • WEDGE OR RIDGE • COL • STRAIGHT ISOBARS

DEPRESSIONS A depression, as its name implies, is a region of low barometric pressure and appears on the synoptic chart as a set of closed curved isobars with winds circulating anticlockwise in the northern hemisphere, clockwise in the southern hemisphere. The warm and cold fronts associated with depressions bring with them characteristically unsettled weather. Depressions vary from between 200 and 2, 000 miles in diameter; they may be deep when pressure at their centre is very low and the isobars are tightly packed, or shallow when less well developed

DEPRESSIONS A depression develops like the propagation of a wave in water. Initially, a uniform boundary or front exists between cold air pushing southwards and warm air pushing northwards. A wave-shaped distortion may appear on the front, and a small low pressure centre develops at the crest of the wave. In the immediately surrounding area the pressure begins to fall. A disturbance of this kind is called a wave depression. As the «wave» develops, a warm sector of air forms, bounded by the warm and cold fronts, which begins to tie over the engulfing cold air. Both the warm and cold fronts originate from the centre of the depression. On the ground, sudden changes in the wind direction may be experienced when fronts pass by.

What is a cyclone ? • It is a center of low pressure. • The pressure decreases from the outer isobars towards the center.

LOW PRESSURE AREAS-DEPRESSIONS AND CYCLONES

Stage 1 Pm Tm Polar air travels towards tropical air

Stage 2 Pm Tm Cold polar air starts to cut under the lighter, warm tropical air making it rise. The rising air creates a low pressure on the ground

Stage 3 Pm Tm A spinning depression is formed with a warm front and a cold front. Winds always spin anticlockwise.

Stage 4 Pm Tm The depression starts to die as the warm air is forced to rise

Stage 5 A dead depression. Winds die down (isobars spread apart) and the rain stops

http: //whs. moodledo. co. uk/mod/resource/view. php? id=

DEFINITIONS • DEEPENING OF THE LOW PRESSURE ; • DECREASING OF THE PRESSURE OF THE LOW PRESSURE CENTER • FILLING OF THE LOW PRESSURE ; • INCREASING OF THE PRESSURE OF THE LOW PRESSURE CENTER • WEAKENING OF THE PRESSURE ; • DECREASING THE MAGNITUDE OF THE PRESSURE GRADIENT AROUND THE PRESSURE CENTER. • STRENGHTENING OF THE PRESSURE ; • INCREASING THE MAGNITUDE OF THE PRESSURE GRADIENT AROUND THE PRESSURE CENTER.

CYCLOGENESIS • THE PROCESS WHEREBY A NEW CYCLONE OR DEPRESSION IS FORMED, OR AN EXISTING ONE IS STRENGTHENED • MOSTLY EXISTS AT MID AND HIGH LATTITUTES IN THE FRONTAL TROUGHS • IT IS THE PROCESS OF DECREASING THE PRESSURE OF THE LOW PRESSURE CENTER MORE RAPIDLY THAN THE SURROUNDING PRESSUR

CYCLOLYSIS • THE DISAPPEARANCE OR WEAKINING OF AN EXISTING CYCLONE OR DEPRESSION IS KNOWN AS CYCLOLYSIS. • IT IS THE PROCESS OF INCREASING PRESSURE OF LOW PRESSURE CENTER MORE RAPIDLY THAN THE SURROUNDING PRESSUR

FORMATION OF NON-FRONTAL DEPRESSION

FLOWS OF LOW AND HIGH PRESSURE AREAS

CEPHESİZ SİKLONLAR- NON-FRONTAL DEPRESSIONS TYPES OF NON FRONTAL DEPRESSION • THERMAL DEPRESSIONS (m. P) INSTABILITY DEPRESSIONS (POLAR DEPRESIONS) • OROGRAPHIC DEPRESSIONS ( LEE DEPRESSIONS)

THERMAL DEPRESSIONS

THERMAL DEPRESSIONS

INSTABILITY DEPRESSION

OROGRAPHIC DEPRESSIONS(LEE DEPRESSION)

OROGRAPHIC DEPRESSIONS(LEE DEPRESSION)

Anticyclones Air flows clockwise around a high-pressure system in the northern hemisphere. Air tends to sink near high-pressure centers, which inhibits precipitation and cloud formation.

Air circulation around a high pressure system Air circulation around a low pressure system

H & L pressure circulation drives the wind Global Scale: High and Low pressure systems develop

Highs and Lows Cyclones – centers of low pressure Anticyclones – centers of high pressure In cyclones, pressure decreases from the outer isobars toward the center In anticyclones, the values of the isobars increase from the outside toward the center When the pressure gradient and the Coriolis effect are applied to pressure centers in the Northern Hemisphere, wind blows counterclockwise around a low and clockwise around a high In either hemisphere, friction causes a net flow of air inward around a cyclone and a net flow outward around an anticyclone

What is the rotation of cyclones & anticyclones in the Northern Hemisphere ? • When the Coriolis effect are applied to LOW pressure centers: – and counter-clockwise around the low. • When the Coriolis effect are applied to HIGH pressure centers: – and clockwise around the high.

How does friction affect the flow of cyclones & anticyclones? • In either hemisphere, friction causes – Air to flow INWARD around a CYCLONE (LOW). – Air to flow OUTWARD around an ANTICYCLONE (HIGH).

Airflow Associated with Cyclones and Anticyclones

Cyclonic and Anticyclonic winds

ANTICYCLON

ANTICYCLON

COLD ANTICYCLON

WARM ANTICYCLONES

PRESSURE AND WIND DISTRIBUTION(JANUARY)

PRESSURE AND WIND DISTRIBUTION(JULY)

A FAMILY OF DEPRESSION

A FAMILY OF DEPRESSION

SECONDARY DEPRESSION

DEPRESSIONS • Wave depressions can grow off the tail ends of primary cold fronts. • The depression so formed is then called a secondary depression. New centres may also develop at the point of occlusion within the primary depression. The secondary system can then become the main system, and the primary occluded front becomes caught up in the developing circulation, effectively becoming a third front.

FORMATION OF SECONDARY DEPRESSION

SECONDARY DEPRESSION • SECONDARY DEPRESSION IS CAUSED BY THE OROGRAPHIC IMPACTS AND GENERALLY IS ORIGINATED AT THE PASSAGE FROM THE SEA TO THE LAND OR OVER THE MOUNTAIN CHAIN.

TROUGH OF LOW PRESSUR

TROUGH OF LOW PRESSURE • GENERALLY BAD WEATHER EXISTS IN FRONT OF THE TROUGH( CLOUDY WITH PRECIPITATION), • AFTER THE PASSAGE OF TROUGH CLEAR WEATHER EXISTS.

RIDGE PRESSUE AND WIND DISTRIBUTION

RIDGE PRESSUE AND WIND DISTRIBUTION

COL

COL When two anticyclonic systems and two cyclonic systems are diametrically opposed there is an area in the centre of the four systems which cannot be considered as a high pressure or a low pressure area . This area is known as a COL and the pressure is lower than that round the high pressures and higher than that round the low pressures. In a col the pressure gradients are small. giving light variable winds. In general the relative humidity is high and there may be fog , or there may be thunderstorms.

COL • THERE ARE SLIGHT AND VARIABLE WINDS AT THE CENTER OF COL. • IN WINTER AND AUTUMN AT THE COL OVER THE LAND FOG IS MOST LIKELY • IF THERE IS AMPLE HUMIDITY AND UNSTABILITY OVER THE COL IN SUMMER, THUNDERSTORM IS MOST LIKELY

TROPHICAL ROVELVING STORM(TRS)

Tropical revolving storms occur all around the world, but are called different names. 11% 17% 8% 11% 20% 33%

TROPHICAL CYCLONS

TROPHICAL ROVELVING STORM(TRS)

Tropical storms form between 5ºand 20º North & South of the equator. They need warm water ~ above 27ºc – hence their location. As the Earth rotates, this provides the ‘spin’ needed to start the tropical storm on its journey across the Atlantic towards America.

Warm Oceans The ‘food’ of a tropical storm is the warm moist water found near the equator. The air here is under LOW pressure, which means it can lift easily. This lifting encourages the air to cool and condense, as it does latent heat is released. This is the name given to energy produced when a substance changes state ie vapour to a liquid.

Here is a check list of what is needed for a tropical revolving storm to grow. A storm can travel anywhere from 15 to 40 mph Once the storm has developed it can grow 400 miles wide.

Here is a 3 D image of a Tropical revolving storm. Notice the lower level winds being drawn in and spiralling counter clockwise. The lines ‘isobars’ get closer together, indicating faster flowing air.

EYE -a roughly circular area of light winds mostly devoid of clouds. It is the region of lowest surface pressure and warmest temperatures alof Eyes range in size from 8 km to over 200 km (generally 30 -60 km ) across Eye wall -a circular rotating region of intense thunderstorms extending up to the tropopause (~ 15 km). Area of highest surface winds Spiral rain bands – lines of thunderstorms , spiraling anticlockwise (in N. hemisphere) In the “ eye ” air is slowly sinking (causes compressional warming and “warm core”) The eye wall has a net upward airflow as a result of numerous updrafts and downdrafts. Near the top of the eye-wall clouds relatively dry air flows outwards from the centre. This diverging air aloft extending outwards for 100 s km. As the outflow reaches the cyclones edges it sinks In the spiral rain bands , air converges at the surface, ascends through these bands, diverges aloft, and descends on both sides of the band. STRUCTURE OF A TROPHICAL CYCLON

TROPHICAL ROVELVING STORM(TRS )

STAGE 1: tropical disturbance a cluster of disorganized thunderstorms w/o rotation over the tropical ocean waters Winds 0 -20 kts (23 mph) STAGE 2 : tropical depression organized circulation in the centre of the thunderstorm complex with identifiable surface pressure drop (1 isobar) Winds between 20 and 34 knots (23 — 39 mph). STAGE 3 : tropical storm Thunderstorms becoming organized –closed isobars, cyclonic rotation Winds between 35 -64 knots (39 -73 mph) STAGE 4 : hurricane Intense, closed cyclonic system around central core Hurricane 64 kts (74 mph =120 km/h) TROPICAL CYCLONE DEVELOPMENT

TROPHICAL ROVELVING STORM(TRS)

TROPHICAL ROVELVING STORM(TRS)

TROPHICAL ROVELVING STORM(TRS)

TROPHICAL ROVELVING STORM(TRS)

TROPHICAL ROVELVING STORM(TRS)

TROPHICAL ROVELVING STORM(TRS)

TROPHICAL ROVELVING STORM(TRS )

TROPHICAL ROVELVING STORM(TRS )

TROPHICAL CYCLONES

TROPHICAL CYCLONES

TROPHICAL CYCLONES

SIGNS OF TROPHICAL CYCLONES APPROACH

TROPHICAL CYCLONES

TROPHICAL ROVELVING STORM

TROPHICAL ROVELVING STORM

TROPHICAL STORM

TROPHICAL STORM

TROPHICAL STORM

TROPHICAL STORM

TROPHICAL STORM

TROPHICAL STORM

TROPHICAL STORM

AVOIDING FROM THE STORM

AVOIDING FROM THE STORM

AVOIDING FROM THE STORM

AVOIDING FROM THE STORM

AVOIDING FROM THE STORM

AVOIDING FROM THE STORM

AVOIDING FROM THE STORM

What Exactly Is A Tornado? Violently rotating column of air (Vortex) extending from a thunderstorm to the ground

TORNADOES

TORNADOES

TORNADOLAR -TORNADOES • GENERAL CHARACTERISTICS ORBIT— 300 YDS-300 MILE DIAMETER-1 -2 m or 1. 5 km. average 250 m. WIND SPEED. 350 -700 km/h VERTICAL WIND SPEED 250 -300 km. /h ADVENCE SPEED 30 -80 km. /h

How Strong Are Tornados? Strength is measured by the Fujita Scale. . . F 0 = weakest, F 5 = Strongest

TORNADOES

WATERSPOUTS

According to NOAA’s National Weather Service , THE BEST WAY TO AVOID A WATERSPOUT IS TO MOVE AT A 90 -DEGREE ANGLE TO ITS APPARENT MOVEMENT. Never move closer to investigate a waterspout. Some can be just as dangerous as tornadoes. Waterspouts fall into two categories : fair weather waterspouts and tornadic waterspouts. TORNADIC WATERSPOUTS are tornadoes that form over water , or move from land to water. They have the same characteristics as a land tornado. They are associated with severe thunderstorms , and are often accompanied by high winds and seas, large hail, and frequent dangerous lightning. FAIR WEATHER WATERSPOUTS usually form along the dark flat base of a line of developing cumulus clouds. This type of waterspout is generally not associated with thunderstorms. While tornadic waterspouts develop downward in a thunderstorm, a fair weather waterspout develops on the surface of the water and works its way upward. By the time the funnel is visible, a fair weather waterspout is near maturity. Fair weather waterspouts form in light wind conditions so they normally move very little. If a waterspout moves onshore , the National Weather Service issues a tornado warning, as some of them can cause significant damage and injuries to people. TYPICALLY, FAIR WEATHER WATERSPOUTS DISSIPATE RAPIDLY WHEN THEY MAKE LANDFALL, AND RARELY PENETRATE FAR INLAND. The water spout season usually begining in may and ends in October WATER SPOUTS

Water Spouts. A water spout is a intense vortex. It occurs over a body of water and connected to a cumuliform cloud. It is a non-super cell tornado over water. Water spouts form when a tornado forms over the ocean , lakes or rivers. They form when a high layer of cool air blows across water and warm air sweeps in from behind. They appear as thin columns over a body of water.

CODING OF METEOROLOGICAL INFORMATION

CODING OF METEOROLOGICAL INFORMATION

CODING OF METEOROLOGICAL INFORMATION

CODING OF METEOROLOGICAL INFORMATION

CODING OF METEOROLOGICAL INFORMATION

CODING OF METEOROLOGICAL INFORMATION

CODING OF METEOROLOGICAL INFORMATION

CODING OF METEOROLOGICAL INFORMATION

WEATHER ROUTHING

Optimum Ship Routing (Weather Routing ) Optimum ship routing is the art and science of developing the “ best route ” for a ship based on the existing weather forecasts, ship characteristics, ocean currents and special cargo requirements. For most transits this will mean the minimum transit time that avoids significant risk to the vessel, crew and cargo. Other routing considerations might include passenger comfort, fuel savings or schedule keeping. The goal is not to avoid all adverse weather but to find the best balance to minimize time of transit and fuel consumption without placing the vessel at risk to weather damage or crew injury. A preliminary routing message is transmitted to the master of a vessel prior to departure with a detailed forecast of expected storm tracks , an initial route proposal with reasoning behind the recommendation and also the expected weather conditions to be encountered along that route or any alternate routes. This allows the master to better plan his route and offers an opportunity to communicate with the routing service any special concerns that he or she might have due to special cargo requirements or ship condition. .

Ship Routing (Weather Routing ) Once the vessel departs, the vessel’s progress is monitored closely with weather and route updates sent as needed. Routing services save ship operators money by reducing the average time of transit and therefore also saving on fuel. By avoiding the worst weather conditions , weather routing minimizes the risk for damage to cargo or ship as well as the risk of injury to crew or passengers. Over time, routed ships benefit from reduce insurance premiums as well based on an improved track record. Modern ship routing ideas began during the early stages of WWII when the US Navy established the “ Naval Meteorology and Oceanography Center ” at the Naval Air Station in Norfolk in 1958. Optimum Track Ship Routing ” (OTSR) was started to provide tailored safety and cost saving routing services to all ships utilized by the military for long duration open ocean voyages.

WEATHER ROUTING

METEOTOLOGICAL FACTORS OF PLANNING AN OCEAN VOYAGES

WEATHER ROUTING

WEATHER ROUTING

WEATHER ROUTING

WEATHER ROUTHEING

WEATHER FORECAST

WEATHER FORECAST

WEATHER FORECAST

WEATHER FORECAST

WEATHER FORECAST

WEATHER FORECAST

WEATHER FORECAST FOG WİLL GENERALLY FORM WHEN: The sky is clear at sunset, the wind is light, and the air is humid. Warm rain is falling through cold air ahead of a warm front. There is a large temperature difference between relatively warm water and much colder air above it. There is a sustained flow of warm, moist air northward (from the south) over a colder surface (either land or water). Remember to watch carefully the temperature-dew point spread.