AIR PRESSURE AND WIND AIR PRESSURE AND WIND
TEMPORAL AND SPATIAL CHANGES OF TEMPORAL AND SPATIAL CHANGES OF
CLIMATE ELEMENTS IN HUNGARY
CLIMATE ELEMENTS IN HUNGARY
Air Air pressure pressure
Different
Different warmingwarming of theof the Earth’Earth’ss surfacesurface generatesgenerates air pressureair pressure differences
differences inin thethe atmosphereatmosphere abiveabive thethe surface. surface. InIn orderorder toto compensate
compensate airair-pressure-pressure differences, differences, airair particlesparticles movemove fromfrom hig-hig- pressure
pressure areasareas toto low-low-pressurepressure areas. a levegareas. a levegőrőréészecskszecskék ék elmozdulnak a magas nyom
elmozdulnak a magas nyomáássúú terüterületek irletek iráánynyáábbóól az alacsony l az alacsony nyományomássúú terüterületek felletek feléé. . ThisThis horizontalhorizontal airflowairflow is calledis called windwind. . Therefore
Therefore, air , air pressurepressure has has directdirect and indirectand indirect associationassociation withwith several
several climaticclimatic elements. elements. ThisThis is oneis one of theof the most most basicbasic climaticclimatic elements
elements. .
AsAs a a resultresult, , inin thethe earlyearly 20th 20th centurycentury, a , a widewide rangerange of of meteorological
meteorological phenomenaphenomena werewere triedtried toto explainexplain onon air air pressurepressure basis
basis. . LaterLater, , thisthis approachapproach waswas pushedpushed intointo thethe backgroundbackground..
OneOne elementelement of preparingof preparing recentrecent large-large-scalescale weatherweather forcastsforcasts is is analysis
analysis of air pressureof air pressure -- topographictopographic maps.maps. Beacuse
Beacuse of itsof its physiologicalphysiological effectseffects (human biometeorology(human biometeorology) ) itit is is alsoalso important.important.
Temporal
Temporal dynamics dynamics of air of air pressure pressure
Daily course of air pressure between the Equator and the 60°N latitude
Air pressureAir pressure is theis the most stablemost stable climaticclimatic element. element. ItsIts dailydaily and annualand annual fluctuations
fluctuations areare onlyonly upup toto somesome %. %.
ItsIts dailydaily coursecourse show a doubleshow a double wave: wave: thethe main maximum is aroundmain maximum is around 10-10- 11 am;
11 am; whilewhile thethe main minimum is aroundmain minimum is around 44-5 -5 óóra pmra pm; ; secondarysecondary maximum is
maximum is aroundaround 10-10-11 am; 11 am; secondarysecondary minimum is minimum is aroundaround 44-5 am.-5 am.
The amplitiudeThe amplitiude of theof the dailydaily pendulumpendulum decreasesdecreases fromfrom thethe EquatorEquator toto thethe poles
poles. The . The regularregular dailydaily pendulumpendulum inin Hungary is generallyHungary is generally 11-6 -6 mbmb, , whilewhile passing
passing throughthrough of a of a weatherweather front mayfront may causecause eveneven a penduluma pendulum of of 10-10-20 mb.20 mb.
ItsIts annualannual coursecourse alsoalso showsshows a doubela doubel wave.wave. Main minimum:
Main minimum: AprilApril-May-May (midlatitude cyclones coming from the( direction of the Icelandic minimum).).
Main maximum:
Main maximum: JanuaryJanuary (anticyclones(anticyclones breakingbreaking intointo thethe CarpathianCarpathian basin
basin fromfrom thethe directiondirection of theof the SiberianSiberian maximum).maximum).
Secondary
Secondary minimum: Julyminimum: July (due to the strong warming of the central( part of the basin).).
Secondary
Secondary maximum: maximum: September-September-OctoberOctober ((anticyclonesanticyclones breakingbreaking intointo thethe CarpathianCarpathian basinbasin fromfrom thethe directiondirection of of thethe AzoreanAzorean maximum).maximum).
Annual course of air pressure, Debrecen, 1928-1978;
900+…hPa, or 1000+…hPa
Annual course of air pressure, 1901-1950, hPa
The The pendulumpendulum of of meanmean monthlymonthly air air pressurepressure is is betweenbetween 9.0 and 9.0 and 25.0 mb.
25.0 mb.
InIn winter, winter, thethe pendulumpendulum is higheris higher (23.0-(23.0-25.0 mb) 25.0 mb) duedue toto thethe frequent
frequent anticyclonicanticyclonic large-large-scalescale weatherweather situations, situations, whilewhile inin summer
summer itit is smalleris smaller (9.0-(9.0-10.0 mb) due10.0 mb) due toto thethe higherhigher frequencyfrequency of of thethe cycloniccyclonic large-large-scalescale weatherweather situations. The situations. The absoluteabsolute
pendulum
pendulum is 70is 70-80 mb.-80 mb.
InIn thethe mountainousmountainous areasareas air pressureair pressure decreasesdecreases withwith height, height, withwith an averagean average of 10of 10-12 mb / 100 m. -12 mb / 100 m.
The The decreasedecrease inin air pressureair pressure is higheris higher inin coldcold air inair in winter, winter, whilewhile itit is smalleris smaller inin warmwarm air inair in summersummer..
Vertical gradient of air pressure, hPa / 100 m
1. Between Budapest Szabadság-hegy and Budapest Meteorological Institute;
2. Between Kékestető and Mátraháza (30-year mean);
Areal distribution of mean annual sea level air pressure in Hungary, hPa
According
According toto thethe map of arealmap of areal differencesdifferences of seaof sea levellevel air pressureair pressure, , relatively
relatively lowlow meanmean seasea levellevel airair pressurepressure occursoccurs atat thethe centralcentral part part of Hungary;
of Hungary; furthermorefurthermore, , seasea levellevel air pressureair pressure is relativelyis relatively lowlow bothboth inin JanuaryJanuary and Julyand July..
Towards
Towards thethe edgeedge areas, i.e. areas, i.e. towardstowards west, west, northnorth and and northnorth-east-east thethe air pressureair pressure increases.increases.
The lowThe low pressurepressure areaarea atat thethe centralcentral part of Hungary is duepart of Hungary is due toto thethe basin
basin--effecteffect: over : over thethe stronglystrongly warmingwarming centralcentral part thepart the air pressureair pressure is smalleris smaller..
Foehn
Foehn windwind comingcoming fromfrom thethe AlpsAlps inin thethe westwest and and fromfrom thethe Carpathians
Carpathians inin thethe easteast causecause an increasean increase inin air pressureair pressure atat thethe edgeedge areas.areas.
Areal
Areal differencesdifferences areare of thousandthof thousandth magnitudemagnitude: in: in an annualan annual average
average thethe differencedifference is 0.8 mbis 0.8 mb; ; inin winterwinter itit is 0.4 mbis 0.4 mb; ; whilewhile inin summer
summer 1.4 mb.1.4 mb.
A tengerszintre
A tengerszintre
Mean sea level air pressure in Hungary, January, hPaátsz á tsz ám á m ított í tott á á tlagos l tlagos l é é gnyomá gnyom á s janu s janu ári t á ri t érk é rké épe pe
A tengerszintre
A tengerszintre
Mean sea level air pressure in Hungary, July, hPaá á tsz tsz á á m m í í tott tott á á tlagos l tlagos l é é gnyom gnyom á á s j s j ú ú liusi t liusi t é é rk rk é é pe pe
Wind Wind
Wind, Wind, similarlysimilarly toto solarsolar radiation, is a radiation, is a meteorologicalmeteorological elementelement of of basical
basical importance, importance, becausebecause itit influencesinfluences almost allalmost all meteorologicalmeteorological elements
elements..
WindWind is a vectoris a vector, , itit cancan be characterizedbe characterized byby itsits strengthstrength ((windwind speedspeed -- m/s) and directionm/s) and direction (wher(wher fromfrom itit blowsblows –– orientation, orientation, degreedegree, or, or a a direction
direction scalescale of 32).of 32).
DueDue toto thethe meridionalmeridional heatheat exchangeexchange, , windwind directionsdirections areare notnot soso stable
stable inin thethe temperatetemperate beltbelt comparedcompared toto thethe thethe tropicstropics oror thethe polarpolar areas
areas. . While
While inin thethe passpass beltbelt thethe relativerelative frequencyfrequency of of thethe prevailingprevailing windwind is is 70-70-80%, 80%, inin thethe CarpathianCarpathian basinbasin thisthis ratio is a ratio is a meremere 15-15-35%.35%.
Relative frequency of different wind directions in Hungary, %, 1901-1950
Station Calm
Prevailing wind directions in Hungary
Regarding
Regarding thethe prevailingprevailing windwind directions, 4 directions, 4 characteristiccharacteristic regionsregions cancan be distinguishedbe distinguished inin Hungary:Hungary:
1. Northwesterlies1. Northwesterlies: in: in KisalföKisalföld, ld, thethe largelarge part of Dunápart of Dunántúntúli li MediumMedium-- highhigh MountainsMountains and betweenand between DanubeDanube andand Tisza RiversTisza Rivers. .
ThisThis is theis the windwind inflowinflow directiondirection throughthrough thethe ”gate”gate”” atat DéDévvéény, ny, which
which is notis not altered byaltered by thethe DunáDunántntúúli li CentralCentral MountainsMountains of of southwest
southwest--northeastnortheast directiondirection strikesstrikes..
2. In2. In thethe areaarea of te Alpsof te Alps and Zala Hillsand Zala Hills northernnorthern windswinds areare characteristic
characteristic. . TheyThey developdevelop byby spreadingspreading out of out of thethe main northmain north-- western
western flow thatflow that enter enter thethe ”wind”wind gate”gate” atat DDévévéény. ny.
InIn thethe areaarea of Zala Hillsof Zala Hills, the, the meridionalmeridional valleyvalley networknetwork furtherfurther strengthens
strengthens thethe near-near-surfacesurface northernnorthern winds.winds.
3. In3. In thethe areaarea of theof the NorthernNorthern MediumMedium-high-high MountainsMountains therethere areare no no anyany prevailingprevailing windwind direction. direction. InIn thethe areaarea of Böof Börzsrzsööny and Cserhány and Cserhát t Mountains
Mountains western windswestern winds, , inin MáMátra tra MopuntainMopuntain northernnorthern winds, winds, inin BüBükk Mountain kk Mountain northnorth--westernwestern winds, winds, inin thethe Aggteleki karstAggteleki karst esternestern winds
winds K-K-i, i, whilewhile inin thethe ZempléZempléni Mountain ni Mountain northnorth--easterneastern windswinds areare characteristic
characteristic. .
AtAt thethe samesame time, time, inin MáMátraalja traalja southsouth--westernwestern, and , and inin BüBükkaljakkalja south
south--easterneastern windswinds areare thethe most frequentmost frequent. . Along
Along riverriver valleysvalleys (Zagyva, Hern(Zagyva, Hernád) ád) northernnorthern windswinds areare most most common
common..
4. In4. In TiszáTiszántntúúl l northeasternnortheastern windswinds prevailprevail, together, together withwith south-south-westernwestern winds
winds. .
ItsIts reasonreason is theis the TiszáTiszántntúúli li windwind channel. channel. ContinentalContinental air massesair masses crossing
crossing thethe ridgeridge of aroundof around 1000 m height1000 m height of NEof NE--CarpathiansCarpathians getget intointo thethe windwind channelchannel betweenbetween thethe ZempléZempléni Mountain and ni Mountain and ApuseniApuseni Mountains
Mountains.. Relative
Relative frequencyfrequency of windof wind directionsdirections usedused toto be presentedbe presented byby windwind direction
direction diagrams. diagrams. FromFrom thesethese notnot onlyonly thethe prevailingprevailing windwind directions
directions butbut alsoalso thethe frequencyfrequency of windof wind directionsdirections cancan be be displayed.
displayed.
Mean annual wind roses in Hungary
AsAs itit cancan be be seenseen fromfrom thethe tabletable belowbelow, , wellwell over over thethe frictionfriction layerlayer, , atat 5 km 5 km heightheight aboveabove surfacesurface, , wherewhere thethe windwind directiondirection changingchanging effect
effect of of thethe relief is no relief is no longerlonger presentpresent, , thethe picturepicture is is muchmuch more more uniform.
uniform.
InIn 59% of 59% of thethe casescases windwind blowsblows fromfrom west, west, whichwhich correspondscorresponds toto thethe typicaltypical basicbasic westerlieswesterlies inin thethe temperatetemperate beltbelt..
Relative frequency of wind directions (%) at 5 km height above surface in Hungary
N NE E SE S SW W NW
Another
Another importantimportant characterisrticcharacterisrtic of windof wind is speedis speed. . ItsIts valuevalue isis highly
highly influencedinfluenced byby thethe basinbasin locationlocation of Hungary: meanof Hungary: mean annualannual windwind speedspeed (at(at 10 m 10 m heightheight) is between) is between 22-4 m/s.-4 m/s.
Regarding
Regarding Europe, thisEurope, this windwind speedspeed countscounts low. The low. The CarpathianCarpathian basin
basin cancan be consideredbe considered protectedprotected fromfrom windwind.. Especially
Especially strongstrong windwind protectionprotection is characteristicis characteristic inin thethe SE SE foreground
foreground of theof the medium-medium-highhigh mountains.mountains.
WindWind speedspeed over Hungary is featuredover Hungary is featured byby springspring ((March, March, April) April) maximum and
maximum and autumnautumn ((SeptemberSeptember) minimum.) minimum.
Daily
Daily coursecourse of windof wind speedspeed cancan be describedbe described byby earlyearly afternoonafternoon maximum and
maximum and earlyearly morningmorning minimum.minimum.
The consequenceThe consequence of theof the topographytopography and and basinbasin charactercharacter is thatis that invasion
invasion of of differentdifferent air air massesmasses intointo thethe basinbasin is delayedis delayed, , atat thethe samesame timetime anticyclopnicanticyclopnic large-large-scalescale weatherweather situationssituations persist.persist.
Prevailing wind direction and mean wind speedin Hungary, summer half-year, m/s, several-year means (after Kakas)
Prevailing wind direction and mean wind speed in Hungary, winter half-year, m/s, several-year means (after Kakas)
Always look on the bright side of things!
We finished for today, goodbye!
ق ا ا إ اد د
ق ا ا إ اد د
ﻣ ﻣ ! ! ء ء ا ا
让我们总是从光明的一面来看待事 物吧！
今天的课程到此结束，谢谢！
