{"id":57212,"date":"2017-06-21T10:25:59","date_gmt":"2017-06-21T09:25:59","guid":{"rendered":"https:\/\/elspeedo.cz\/?page_id=57212\/"},"modified":"2017-06-21T10:25:59","modified_gmt":"2017-06-21T09:25:59","slug":"atmosfericke-fronty","status":"publish","type":"page","link":"https:\/\/elspeedo.cz\/pl\/e-learning\/atmosfericke-fronty\/","title":{"rendered":"Atmosf\u00e9rick\u00e9 fronty"},"content":{"rendered":"
[vc_row][vc_column][vc_column_text disable_pattern=”false”]Podstata vzniku front<\/strong>
\nAtmosf\u00e9rick\u00e9 fronty vznikaj\u00ed na rozhran\u00ed dvou vzduchov\u00fdch hmot. Nejprve si mus\u00edme objasnit term\u00edn vzduchov\u00e1 hmota. Je to mno\u017estv\u00ed vzduchu, lidoveck\u00fdm term\u00ednem \u0159e\u010deno v\u011bt\u0161\u00ed ne\u017e velk\u00e9, tedy horizont\u00e1ln\u011b stovky a\u017e tis\u00edce kilometr\u016f, kter\u00e9 se del\u0161\u00ed dobu nal\u00e9z\u00e1 nad zemsk\u00fdm povrchem s ur\u010ditou charakteristikou a tuto charakteristiku od zemsk\u00e9ho povrchu p\u0159eb\u00edr\u00e1.<\/p>\n

Vzduchov\u00e9 hmoty se rozd\u011bluj\u00ed jednak podle, zjednodu\u0161en\u011b \u0159e\u010deno, zem\u011bpisn\u00e9 \u0161\u00ed\u0159ky, ve kter\u00e9 se formuj\u00ed, tak podle povrchu nad kter\u00fdm vznikaj\u00ed. Dal\u0161\u00ed rozd\u011blen\u00ed si budeme popisovat podle zem\u011bpisn\u00e9 \u0161\u00ed\u0159ky, je v\u0161ak d\u016fle\u017eit\u00e9 si uv\u011bdomit, \u017ee ka\u017ed\u00e1 vzduchov\u00e1 hmota m\u016f\u017ee m\u00edt dv\u011b varianty: mo\u0159skou (oce\u00e1nskou) \u010di pevninskou (suchozemskou). Hlavn\u00ed rozd\u00edl mezi t\u011bmito variantami spo\u010d\u00edv\u00e1 ve vlhkosti vzduchu. Tak\u017ee se na to poj\u010fme pod\u00edvat zbl\u00edzka, a vezmeme to p\u011bkn\u011b popo\u0159ad\u011b od p\u00f3lu k rovn\u00edku.<\/p>\n

V okol\u00ed p\u00f3l\u016f se nach\u00e1z\u00ed vzduch, kter\u00fd se naz\u00fdv\u00e1 arktick\u00fd (na ji\u017en\u00ed polokouli pak antarktick\u00fd). Tento vzduch je velmi studen\u00fd a vzhledem k jeho extr\u00e9mn\u011b n\u00edzk\u00e9 teplot\u011b i pom\u011brn\u011b such\u00fd: tak studen\u00fd vzduch je prost\u011b neschopen udr\u017eet v sob\u011b v\u011bt\u0161\u00ed mno\u017estv\u00ed vodn\u00ed p\u00e1ry. Toto je v\u011bc pochopiteln\u00e1, p\u0159esu\u0148me se tedy kousek d\u00e1le od p\u00f3lu a pod\u00edvejme se na mapu sv\u011bta. Co tam uvid\u00edme? Pom\u011brn\u011b studen\u00e1 mo\u0159e a oce\u00e1ny, na pevnin\u011b pak zejm\u00e9na tajgu a tundry, p\u0159\u00edpadn\u011b rozlehl\u00e9 seversk\u00e9 lesy. Logicky z toho vypl\u00fdv\u00e1, \u017ee vzduch nad takov\u00fdmto ter\u00e9nem bude pom\u011brn\u011b chladn\u00fd, z\u00e1rove\u0148 v\u0161ak dosti vlhk\u00fd. Tato vzduchov\u00e1 hmota, a\u010dkoli nele\u017e\u00ed na p\u00f3lech ani v jejich bl\u00edzkosti, se naz\u00fdv\u00e1 pon\u011bkud nelogicky pol\u00e1rn\u00ed. Ob\u010das se pou\u017e\u00edv\u00e1 n\u00e1zev \u201evzduchov\u00e1 hmota m\u00edrn\u00fdch \u0161\u00ed\u0159ek\u201c, no a poj\u010fme d\u00e1le: n\u00e1sleduje oblast subtropick\u00e1, tedy Saharsk\u00e1 pou\u0161\u0165, arabsk\u00e9 pou\u0161t\u011b, pou\u0161\u0165 Gobi, africk\u00e9 savany a rozs\u00e1hl\u00e9 rusk\u00e9, kaza\u0161sk\u00e9 a jin\u00e9 stepi, americk\u00e9 pr\u00e9rie, na ji\u017en\u00ed polokouli pampy.. Tento vzduch je velmi hork\u00fd a such\u00fd a, op\u011bt \u201elogicky\u201c, a\u010dkoli poch\u00e1z\u00ed ze subtropick\u00fdch oblast\u00ed, naz\u00fdv\u00e1 se vzduch tropick\u00fd. A tak jsme se dostali do samotn\u00fdch trop\u016f, do okol\u00ed rovn\u00edku. Vzduchov\u00e1 hmota v okol\u00ed rovn\u00edku se naz\u00fdv\u00e1 pro zm\u011bnu zcela logicky: rovn\u00edkov\u00e1 nebo t\u00e9\u017e ekvatore\u00e1ln\u00ed (equator- rovn\u00edk). A kdy\u017e si op\u011bt vezmeme na pomoc mapu sv\u011bta, vid\u00edme tepl\u00e1 mo\u0159e a rovn\u00edkov\u00e9 de\u0161tn\u00e9 pralesy.. Ano, je to jednoduch\u00e9: tento vzduch je tepl\u00fd a sou\u010dasn\u011b velmi vlhk\u00fd.<\/p>\n

Jmenovan\u00e9 podnebn\u00ed p\u00e1sy jsou vlastn\u011b d\u016fsledkem glob\u00e1ln\u00ed cirkulace atmosf\u00e9ry, kter\u00e1 vznik\u00e1 v d\u016fsledku rotace Zem\u011b a Coriolisovy s\u00edly. V\u0161imn\u011bte si, \u017ee vlhk\u00e9 p\u00e1sy (tajgy, tundry) jsou v m\u00edstech, kde vzduch stoup\u00e1, tedy se ochlazuje, kondenzuje v n\u011bm vodn\u00ed p\u00e1ra a vznikaj\u00ed sr\u00e1\u017eky. Naproti tomu such\u00e1 p\u00e1sma pou\u0161t\u00ed a savan jsou v m\u00edstech, kde vzduch kles\u00e1 a tedy se oh\u0159\u00edv\u00e1. Za vyschnut\u00ed Sahary tedy evidentn\u011b nemohou lid\u00e9 a Sahara z\u016fstane such\u00e1, dokud se glob\u00e1ln\u00ed cirkulace nezm\u011bn\u00ed (co\u017e je samoz\u0159ejm\u011b mo\u017en\u00e9 jako n\u00e1sledek glob\u00e1ln\u00edch klimatick\u00fdch zm\u011bn, v d\u00e1vn\u00e9 minulosti se klima zm\u011bnilo n\u011bkolikr\u00e1t zcela nez\u00e1visle na p\u0159\u00edtomnosti \u010dlov\u011bka). Na p\u0159ilo\u017een\u00e9m obr\u00e1zku je sch\u00e9ma jak by glob\u00e1ln\u00ed cirkulace fungovala, pokud by Zem\u011b m\u011bla zcela stejnorod\u00fd povrch. Zem\u011b ov\u0161em stejnorod\u00fd povrch nem\u00e1 a n\u00e1sledkem je po\u010das\u00ed takov\u00e9, jak jej zn\u00e1me – tedy neust\u00e1l\u00fd boj r\u016fzn\u00fdch vzduchov\u00fdch hmot.[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]A co d\u00e1l?<\/strong>
\nKdy\u017e se potkaj\u00ed dv\u011b rozd\u00edln\u00e9 vzduchov\u00e9 hmoty, tak se spolu prakticky v\u016fbec nem\u00edchaj\u00ed, chovaj\u00ed se podobn\u011b jako olej a voda. Jen se po sob\u011b klou\u017eou a vz\u00e1jemn\u011b se p\u0159etla\u010duj\u00ed. A proto\u017ee na tohle p\u0159i\u0161li na univerzit\u011b v Bergenu p\u00e1r let po prvn\u00ed sv\u011btov\u00e9 v\u00e1lce, dosud m\u011bli v pam\u011bti v\u00e1le\u010dn\u00e1 jatka a tenhle d\u011bj jim p\u0159ipomn\u011bl d\u011bn\u00ed na front\u011b, nazvali jej atmosf\u00e9rick\u00e1 fronta. Ur\u010duj\u00edc\u00ed veli\u010dinou pro frontu je teplota, l\u00e9pe \u0159e\u010deno rozd\u00edl teplot mezi vzduchem p\u0159ed a za frontou. Tak\u017ee sty\u010dn\u00e1 plocha mezi vzduchov\u00fdmi hmotami se naz\u00fdv\u00e1 front\u00e1ln\u00ed plocha, kterou p\u0159edstavuje pom\u011brn\u011b tenk\u00e1 – n\u011bkolik des\u00edtek a\u017e stovek metr\u016f- p\u0159echodov\u00e1 vrstva. Front\u00e1ln\u00ed plocha je sklon\u011bna k zemsk\u00e9mu povrchu pod velmi ploch\u00fdm \u00fahlem, a to tak, \u017ee tepl\u00fd vzduch, proto\u017ee je leh\u010d\u00ed, je naho\u0159e a t\u011b\u017e\u0161\u00ed studen\u00fd vzduch je dole. M\u00edsto, kde se front\u00e1ln\u00ed plocha st\u00fdk\u00e1 se zemsk\u00fdm povrchem se naz\u00fdv\u00e1 \u010d\u00e1ra fronty, a to je ta \u010d\u00e1ra, kter\u00e1 se zakresluje do synoptick\u00fdch map. Tepl\u00e1 fronta (kdy vzduch, kter\u00fd p\u0159ich\u00e1z\u00ed, je teplej\u0161\u00ed ne\u017e ten p\u016fvodn\u00ed) se zakresluje \u010dervenou \u010d\u00e1rou s oblou\u010dky, proto\u017ee tepl\u00e1 fronta se pohybuje relativn\u011b pomalu. Studen\u00e1 fronta (p\u0159ich\u00e1z\u00ed studen\u00fd vzduch) se zakresluje modrou \u010darou s troj\u00faheln\u00ed\u010dky, proto\u017ee studen\u00e1 fronta je rychlej\u0161\u00ed (troj\u00faheln\u00ed\u010dky maj\u00ed evokovat \u0161ipky, zd\u016fraz\u0148uj\u00edc\u00ed rychl\u00fd postup). A kone\u010dn\u011b okluzn\u00ed fronta, kter\u00e1 vznik\u00e1 spojen\u00edm tepl\u00e9 a studen\u00e9 fronty, se zna\u010d\u00ed fialovou \u010d\u00e1rou, na kter\u00e9 se oblou\u010dky a troj\u00faheln\u00ed\u010dky pravideln\u011b st\u0159\u00eddaj\u00ed. Jak oblou\u010dky, tak troj\u00faheln\u00ed\u010dky se kresl\u00ed v\u017edy ve sm\u011bru postupu fronty, tak\u017ee p\u0159i pohledu na synoptickou mapu m\u00e1me hned jasno, kam kter\u00e1 fronta m\u00e1 nam\u00ed\u0159eno.[\/vc_column_text][vc_separator el_width=”80″ el_class=”basic-separator” css=”.vc_custom_1481625402499{padding-top: 40px !important;padding-bottom: 40px !important;}”][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]\n

Tepl\u00e1 fronta<\/h1>\n[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]Na tepl\u00e9 front\u011b se nic zvl\u00e1\u0161tn\u00edho ned\u011bje, je to d\u011bj pom\u011brn\u011b m\u00e1lo dynamick\u00fd a d\u016fle\u017eit\u00e9 je na n\u00ed jen to, \u017ee se n\u011bjakou dobu ned\u00e1 l\u00e9tat a i pak to nen\u00ed nic moc. Na\u0161t\u011bst\u00ed v na\u0161\u00ed letov\u00e9 sez\u00f3n\u011b p\u0159es n\u00e1s tepl\u00e9 fronty nechod\u00ed moc \u010dasto a v\u011bt\u0161inou ji\u017e dosti nev\u00fdrazn\u00e9. Tepl\u00fd vzduch p\u0159ed sebou \u017eene vzduch studen\u00fd a sou\u010dasn\u011b po n\u011bm vyklouz\u00e1v\u00e1 sm\u011brem nahoru, \u010d\u00edm\u017e se adiabaticky ochlazuje a kondenzuje v n\u011bm vodn\u00ed p\u00e1ra. Sklon front\u00e1ln\u00ed plochy v\u016f\u010di zemsk\u00e9mu povrchu je asi jeden \u00fahlov\u00fd stupe\u0148 a postup fronty je pom\u011brn\u011b pomal\u00fd, kolem t\u0159iceti kilometr\u016f za hodinu. Z hlediska pozorovatele to vypad\u00e1 tak, \u017ee se na obloze objev\u00ed obla\u010dnost typu cirrus, kter\u00e1 postupn\u011b houstne a \u010dasto se spoj\u00ed do jednolit\u00e9 vrstvy cirrostratu.<\/p>\n

To je\u0161t\u011b fronta m\u016f\u017ee b\u00fdt i 800 km od n\u00e1s a cirry, na pohled tenk\u00e9 a ned\u016fle\u017eit\u00e9, ji\u017e zpravidla sta\u010d\u00ed zdusit ve\u0161kerou termiku. Pak, jak se fronta p\u0159ibli\u017euje, se na obloze za\u010dne objevovat obla\u010dnost typu altostratus, zpo\u010d\u00e1tku tenk\u00fd translucidus, p\u0159es kter\u00fd slunce sv\u00edt\u00ed jako p\u0159es matov\u00e9 sklo, pozd\u011bji v\u00fdrazn\u011b tmav\u0161\u00ed a siln\u011bj\u0161\u00ed opacus, p\u0159es kter\u00fd ji\u017e slunce nevid\u00edme. V tuto dobu ji\u017e v hor\u00e1ch v\u011bt\u0161inou zes\u00edl\u00ed v\u00edtr na neletov\u00fd, ned\u011bje se tak v\u0161ak skokov\u011b, ale plynule (tak\u017ee m\u00e1me dost \u010dasu si toho v\u0161imnout a zam\u00ed\u0159it v\u010das na p\u0159ist\u00e1n\u00ed) a z\u00e1rove\u0148 se m\u016f\u017eou objevit prvn\u00ed sr\u00e1\u017eky, v\u011bt\u0161inou ve form\u011b mrholen\u00ed a p\u0159eh\u00e1n\u011bk. Obla\u010dnost postupn\u011b houstne a z\u00e1kladny se sni\u017euj\u00ed, nakonec se objev\u00ed nimbostratus, t\u011b\u017ek\u00fd tmav<\/span>\u00fd mrak<\/span> kter\u00fd sed\u00ed z\u00e1kladnou \u010dasto a\u017e na zemi nebo t\u011bsn\u011b nad n\u00ed – a pr\u0161\u00ed a pr\u0161\u00ed… Ale to u\u017e je fronta tady a cel\u00fd cirkus se t\u00edm kon\u010d\u00ed. P\u016fvodn\u00ed studen\u00fd vzduch je nahrazen tepl\u00fdm, kter\u00fd je velmi \u010dasto zvrstven\u00fd stabiln\u011b a nav\u00edc se nasunul nad studenou zem a termiky se t\u00edm p\u00e1dem pravd\u011bpodobn\u011b nedo\u010dk\u00e1me.[\/vc_column_text][\/vc_column][\/vc_row][vc_row css=”.vc_custom_1481543630042{padding-top: 40px !important;padding-bottom: 40px !important;}”][vc_column][vc_separator el_width=”80″ el_class=”basic-separator”][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]\n

Studen\u00e1 fronta<\/h1>\n[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]To je d\u011bj v porovn\u00e1n\u00ed s teplou frontou dynami\u010dt\u011bj\u0161\u00ed a zaj\u00edmav\u011bj\u0161\u00ed. Studen\u00fd vzduch na sv\u00e9m postupu p\u0159ed sebou vytla\u010duje tepl\u00fd a sou\u010dasn\u011b jej zved\u00e1 do v\u00fd\u0161e, sklon front\u00e1ln\u00ed plochy v\u016f\u010di zemsk\u00e9mu povrchu je v\u011bt\u0161\u00ed, kolem t\u0159\u00ed stup\u0148\u016f a studen\u00e1 fronta m\u00e1 proti tepl\u00e9 front\u011b mnohem rychlej\u0161\u00ed postup. Proto dok\u00e1\u017ee b\u00fdt mnohem z\u00e1ludn\u011bj\u0161\u00ed a nese sebou n\u011bkter\u00e9 nebezpe\u010dn\u00e9 jevy, hlavn\u011b bou\u0159ky. Studen\u00e1 fronta se d\u00e1le d\u011bl\u00ed na dva typy, podle rychlosti postupu a souvisej\u00edc\u00edch jev\u016f.[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]Studen\u00e1 fronta 1. typu
\n<\/b>je fronta, kter\u00e1 p\u0159ech\u00e1z\u00ed pomaleji a je m\u00e9n\u011b dynamick\u00e1. Velmi \u010dasto p\u0159ipom\u00edn\u00e1 opa\u010dn\u011b jdouc\u00ed teplou frontu a dosti \u010dasto se obejde bez bou\u0159ek (ne v\u0161ak v\u017edy!!). Proto\u017ee postupuje pomalu, st\u00edh\u00e1 p\u0159ed sebou vytla\u010dit ve\u0161ker\u00fd tepl\u00fd vzduch, ob\u010das a\u017e po tropopauzu, a zde spo\u010d\u00edv\u00e1 jej\u00ed nejv\u011bt\u0161\u00ed nebezpe\u010d\u00ed: v \u010derstv\u00e9m studen\u00e9m vzduchu za frontou tud\u00ed\u017e ob\u010das chyb\u00ed z\u00e1dr\u017en\u00e1 vrstva, kter\u00e1 brzd\u00ed rozvoj termiky, a tak m\u016f\u017ee za frontou konvek\u010dn\u00ed obla\u010dnost p\u0159er\u016fstat do bou\u0159ek. Na\u0161t\u011bst\u00ed, studen\u00e1 fronta 1.druhu p\u0159es na\u0161e \u00fazem\u00ed chod\u00ed nej\u010dast\u011bji p\u0159es chladn\u011bj\u0161\u00ed polovinu roku, nebo pobl\u00ed\u017e st\u0159ed\u016f tlakov\u00fdch n\u00ed\u017e\u00ed, kdy toho stejn\u011b moc nenal\u00e9t\u00e1me.[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]Studen\u00e1 fronta 2.typu
\n<\/b>se od studen\u00e9 fronty 1.druhu li\u0161\u00ed hlavn\u011b rychlost\u00ed postupu. I v podm\u00ednk\u00e1ch na\u0161eho m\u00edrn\u00e9ho klimatick\u00e9ho p\u00e1sma to m\u016f\u017ee d\u011blat a\u017e 80 km\/h! Od toho se pak odv\u00edj\u00ed dal\u0161\u00ed rozd\u00edly. P\u0159edev\u0161\u00edm je to souvisl\u00fd P\u00c1S BOU\u0158EK na jej\u00edm \u010dele. Proto se t\u00e9to front\u011b taky n\u011bkdy, by\u0165 neodborn\u011b (nebo ve star\u0161\u00ed literatu\u0159e) \u0159\u00edk\u00e1 fronta bou\u0159kov\u00e1.<\/p>\n

Jedno z nebezpe\u010d\u00ed bou\u0159ek spo\u010d\u00edv\u00e1 v tom, \u017ee vertik\u00e1ln\u00ed pohyby vzduchu jsou velmi siln\u00e9, stoupav\u00e9 i klesav\u00e9 proudy mohou dosahovat (a tak\u00e9 b\u011b\u017en\u011b dosahuj\u00ed) u\u017e pod z\u00e1kladnou cumulonimbu rychlost\u00ed okolo 20 m\/s, v samotn\u00e9m bou\u0159kov\u00e9m mraku pak a\u017e 50 m\/s. Mezi t\u011bmito stoupav\u00fdmi a klesav\u00fdmi proudy se pak pochopiteln\u011b vyskytuj\u00ed oblasti siln\u00fdch turbulenc\u00ed, kter\u00e9 dok\u00e1\u017eou rozl\u00e1mat i dopravn\u00ed letadlo. Dopravn\u00ed letadla maj\u00ed p\u0159edev\u0161\u00edm z tohoto d\u016fvodu na palub\u011b meteorologick\u00e9 radary a do bou\u0159ek nel\u00e9taj\u00ed \u2013 no a my bychom si z nich m\u011bli vz\u00edt p\u0159\u00edklad..To, \u017ee n\u00e1s m\u016f\u017ee bou\u0159ka vt\u00e1hnout do sebe, vyn\u00e9st a\u017e po tropopauzu (kde si m\u016f\u017eeme dobrovoln\u011b vybrat akor\u00e1t to, jestli bude p\u0159\u00edjemn\u011bj\u0161\u00ed zmrznout nebo se udusit) potom n\u00e1s \u00fahledn\u011b zabalit do vrchl\u00edku jako bonb\u00f3nek a vyexpedovat zp\u00e1tky na zem je a\u017e ten sekund\u00e1rn\u00ed probl\u00e9m. V\u011bt\u0161\u00ed probl\u00e9m je, jak se tomu vyhnout, a v tom je pes zakop\u00e1n: Fronta toti\u017e p\u0159i sv\u00e9m velmi rychl\u00e9m postupu vytla\u010duje tepl\u00fd vzduch do v\u00fd\u0161ky u\u017e pom\u011brn\u011b daleko p\u0159ed vlastn\u00ed \u010darou fronty, a t\u00edm vytv\u00e1\u0159\u00ed ROZS\u00c1HLOU OBLAST STOUPAV\u00ddCH PROUDU (Z vlastn\u00ed zku\u0161enosti to mohu odhadnout na 15 – 20 km.) V t\u00e9to oblasti u\u017e m\u016f\u017ee b\u00fdt docela probl\u00e9m vyklesat, tzn. v\u010das p\u0159ist\u00e1t, pokud neum\u00edte ostrou spir\u00e1lu. A pokud to v\u010das nestihnete, m\u00e1te druh\u00fd probl\u00e9m: n\u011bkolik m\u00e1lo kilometr\u016f p\u0159ed vlastn\u00edmi bou\u0159kami se nal\u00e9z\u00e1 oblast prudk\u00e9ho n\u00e1razov\u00e9ho v\u011btru prom\u011bnliv\u00fdch sm\u011br\u016f. Jednou z jedn\u00e9 strany, za okam\u017eik z druh\u00e9 strany a poryvy m\u016f\u017eou dos\u00e1hnout s\u00edly okolo 20 m\/s. Podstata vzniku tohoto v\u011btru je jednoduch\u00e1: siln\u00e9 klesav\u00e9 proudy nar\u00e1\u017eej\u00ed na zemsk\u00fd povrch, rozl\u00e9vaj\u00ed se po n\u011bm a vytv\u00e1\u0159ej\u00ed siln\u00e9 turbulentn\u00ed poryvy v\u011btru, kter\u00e9 sou\u010dasn\u011b pom\u00e1haj\u00ed odtrh\u00e1vat stoupav\u00e9 proudy a\u0165 u\u017e v samotn\u00e9 bou\u0159ce \u010di v jej\u00edm okol\u00ed, co\u017e dynamiku jevu je\u0161t\u011b zvy\u0161uje. Tenhle jev se naz\u00fdv\u00e1 H\u00daLAVA <\/b>a pokud v\u00e1s chytne, m\u016f\u017eete se akor\u00e1t modlit, aby v\u00e1s to v z\u00e1v\u011bru ne\u0159\u00edzen\u00e9ho, proto\u017ee ne\u0159iditeln\u00e9ho letu hodilo na stromy nebo do lesa, tedy do relativn\u011b m\u011bkk\u00e9ho..<\/p>\n

Jak\u00e1 je pomoc? P\u0159ed l\u00e9t\u00e1n\u00edm SLEDOVAT SYNOPTICKOU P\u0158EDPOV\u011a\u010e <\/b>a pokud se bl\u00ed\u017e\u00ed studen\u00e1 fronta, hl\u00eddat si stranu, odkud m\u00e1 p\u0159ij\u00edt. Vid\u00edte-li v tomto sm\u011bru NA OBZORU souvisl\u00fd p\u00e1s obla\u010dnosti, ne\u010dekat a\u017e se p\u0159ibl\u00ed\u017e\u00ed a OKAM\u017dIT\u011a P\u0158IST\u00c1T![\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]Studen\u00e1 fronta druh\u00e9ho typu m\u00e1 v\u0161ak i sv\u00e9 sv\u011btl\u00e9 str\u00e1nky: p\u0159ech\u00e1z\u00ed pom\u011brn\u011b rychle a hlavn\u011b vy\u010dist\u00ed vzduch, vym\u011bn\u00ed toti\u017e p\u016fvodn\u00ed tepl\u00fd vzduch za studen\u00fd, kter\u00fd je instabiln\u00ed a m\u016f\u017ee se od zem\u011b, kter\u00e1 se v\u011bt\u0161inou nestihne zcela vychladit, dob\u0159e proh\u0159\u00edvat a tud\u00ed\u017e obnov\u00ed v\u00fdborn\u00e9 termick\u00e9 podm\u00ednky. Nav\u00edc p\u0159i sv\u00e9m rychl\u00e9m postupu nestihne vytla\u010dit p\u016fvodn\u00ed tepl\u00fd vzduch po cel\u00e9 v\u00fd\u0161ce troposf\u00e9ry, ale poda\u0159\u00ed se j\u00ed to jen do v\u00fd\u0161ky 3-4 km a t\u00edm nad sebou zanech\u00e1 pom\u011brn\u011b mohutnou v\u00fd\u0161kovou teplotn\u00ed inverzi, kter\u00e1 pak slou\u017e\u00ed jako v\u00fdborn\u00e1 zadr\u017eovac\u00ed vrstva a br\u00e1n\u00ed tak p\u0159ev\u00fdvoji termick\u00fdch kumul\u016f do bou\u0159kov\u00fdch kumulonimb\u016f. A do t\u0159etice v\u0161eho dobr\u00e9ho, velmi \u010dasto vytla\u010d\u00ed \u010d\u00e1st tepl\u00e9ho vzduchu p\u0159ed sebou nikoli dop\u0159edu, n\u00fdbr\u017e nahoru, t\u00edm vytvo\u0159\u00ed jakoby vy\u0161\u0161\u00ed kopec vzduchu a ten se pak za\u010dne sesedat a vytv\u00e1\u0159\u00ed za frontou tlakovou v\u00fd\u0161i.[\/vc_column_text][\/vc_column][\/vc_row][vc_row css=”.vc_custom_1481543630042{padding-top: 40px !important;padding-bottom: 40px !important;}”][vc_column][vc_separator el_width=”80″ el_class=”basic-separator”][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]\n

Okluzn\u00ed fronta<\/h1>\n[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]Okluzn\u00ed fronta vznik\u00e1 tak, \u017ee studen\u00e1 fronta p\u0159i sv\u00e9m rychl\u00e9m postupu do\u017eene teplou, kter\u00e1 je pomalej\u0161\u00ed a tepl\u00fd vzduch, kter\u00fd jde za touto frontou vytla\u010d\u00ed do v\u00fd\u0161ky. Okluzn\u00ed fronty d\u011bl\u00edme na dva druhy, kter\u00e9 rozli\u0161ujeme podle teplotn\u00edho rozd\u00edlu mezi vzduchem p\u0159ed a za frontou. TEPL\u00c1 OKLUZE <\/b>vznikne v p\u0159\u00edpad\u011b, \u017ee vzduch p\u0159ich\u00e1zej\u00edc\u00ed za studenou frontou je teplej\u0161\u00ed, ne\u017e p\u016fvodn\u00ed studen\u00fd vzduch p\u0159ed frontou teplou a tento druh okluze je ve st\u0159edn\u00ed Evrop\u011b \u010dast\u011bj\u0161\u00ed v chladn\u011bj\u0161\u00ed polovin\u011b roku. V teplej\u0161\u00ed polovin\u011b roku, tedy v na\u0161\u00ed hlavn\u00ed letov\u00e9 sez\u00f3n\u011b je u n\u00e1s mnohem b\u011b\u017en\u011bj\u0161\u00ed STUDEN\u00c1 OKLUZE, co\u017e je p\u0159\u00edpad opa\u010dn\u00fd, tedy studen\u00fd vzduch nastupuj\u00edc\u00ed za frontou je chladn\u011bj\u0161\u00ed ne\u017e vzduch p\u0159ed frontou.<\/p>\n

Nejd\u0159\u00edve se p\u0159es n\u00e1s nat\u00e1hne deka vysok\u00e9 obla\u010dnosti, kter\u00e1 zatlum\u00ed a pozd\u011bji zcela zadus\u00ed ve\u0161kerou termiku, pak v\u011bt\u0161inou za\u010dne pr\u0161et no a pak pr\u0161\u00ed docela dlouho a dost. Nebezpe\u010d\u00ed okluzn\u00ed fronty spo\u010d\u00edv\u00e1 v jej\u00ed z\u00e1ke\u0159nosti, proto\u017ee p\u0159es obla\u010dnost p\u016fvodn\u00ed tepl\u00e9 fronty nejsou vid\u011bt bou\u0159ky, kter\u00e9 mohou b\u00fdt na p\u0159ich\u00e1zej\u00edc\u00ed front\u011b studen\u00e9 a mohou se tedy objevit zd\u00e1nliv\u011b zni\u010deho nic. Dal\u0161\u00ed nep\u0159\u00edjemnost\u00ed, spojenou s p\u0159echodem okluzn\u00ed fronty je jej\u00ed pomal\u00fd postup. D\u00e9letrvaj\u00edc\u00ed nevl\u00eddn\u00e9 po\u010das\u00ed n\u00e1m toti\u017e na n\u011bkolik dn\u00ed l\u00e9t\u00e1n\u00ed znemo\u017en\u00ed.[\/vc_column_text][\/vc_column][\/vc_row][vc_row css=”.vc_custom_1481543630042{padding-top: 40px !important;padding-bottom: 40px !important;}”][vc_column][vc_separator el_width=”80″ el_class=”basic-separator”][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]\n

Cykl\u00f3na aneb front\u00e1ln\u00ed syst\u00e9m?<\/h1>\n[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text disable_pattern=”false”]P\u0159edstavme si dv\u011b r\u016fzn\u00e9 masy vzduchu vedle sebe. Mezi nimi bude samoz\u0159ejm\u011b fronta, z po\u010d\u00e1tku se nikam moc neh\u00fdbe, je to takzvan\u00e1 kvazistacion\u00e1rn\u00ed fronta.<\/b> Le\u010d v\u0161eho do \u010dasu. Prvotn\u00ed impuls b\u00fdv\u00e1 v\u011bt\u0161inou rozp\u00edn\u00e1n\u00ed tepl\u00e9ho vzuchu a n\u00e1sledn\u00fd vp\u00e1d tepl\u00e9ho vzduchu do oblasti studen\u00e9ho vzduchu. To se studen\u00e9mu vzduchu pochopiteln\u011b nel\u00edb\u00ed a proto\u017ee tak\u00e9 pot\u0159ebuje sv\u016fj \u201e\u017eivotn\u00ed prostor\u201c, tak vlet\u00ed do oblasti vzduchu tepl\u00e9ho a cel\u00fd syst\u00e9m se rozt\u00e1\u010d\u00ed. Tepl\u00e1 fronta se val\u00ed pomalu kup\u0159edu, ov\u0161em na opa\u010dn\u00e9m konci provazu je fronta studen\u00e1, kter\u00e1 m\u00e1 mnohem v\u011bt\u0161\u00ed dynamiku, je hnan\u00e1 nejen tlakov\u00fdm rozd\u00edlem, ale zapoj\u00ed se zde s\u00edla instability p\u0159ich\u00e1zej\u00edc\u00edho studen\u00e9ho vzduchu. Studen\u00e1 fronta m\u00e1 prost\u011b siln\u011bj\u0161\u00ed motor, a podobn\u011b jako p\u00edsty v motoru bou\u0159ky na \u010dele fronty se prokous\u00e1vaj\u00ed tepl\u00fdm vzduchem a protahuj\u00ed za sebou \u017eiv\u00fd, \u010derstv\u00fd studen\u00fd vzduch.<\/p>\n

Tuto prvn\u00ed f\u00e1ze, kdy se fronty teprve dost\u00e1vaj\u00ed do pohybu, se naz\u00fdv\u00e1 st\u00e1diem front\u00e1ln\u00ed vlny. <\/b>Tepl\u00e1 fronta se rozj\u00ed\u017ed\u00ed, studen\u00e1 fronta za\u010d\u00edn\u00e1 opravdu akcelerovat.. V m\u00edst\u011b front\u00e1ln\u00ed vlny, tedy na m\u00edst\u011b lomu p\u016fvodn\u00ed kvazistacion\u00e1rn\u00ed fronty, za\u010dne vznikat st\u0159ed tlakov\u00e9 n\u00ed\u017ee (d\u016fvod je pom\u011brn\u011b komplikovan\u00fd, ale jednodu\u0161e si m\u016f\u017eeme \u0159\u00edct, \u017ee je to v\u00edr).<\/p>\n

Cel\u00fd syst\u00e9m cykl\u00f3ny se za\u010d\u00edn\u00e1 rozt\u00e1\u010det a v t\u00e9to chv\u00edli ji\u017e m\u016f\u017eeme hovo\u0159it o st\u00e1diu rozv\u00edjej\u00edc\u00ed se cykl\u00f3ny. <\/b>Cykl\u00f3nou naz\u00fdv\u00e1me tlakovou n\u00ed\u017ei s front\u00e1ln\u00edm syst\u00e9mem a tento druh ozna\u010den\u00ed vznikl tak, \u017ee lid\u00e9 si nejd\u0159\u00edve v\u0161imli, \u017ee rotuje tlakov\u00e1 n\u00ed\u017ee a nazvali ji cykl\u00f3nou. Teprve pozd\u011bji si v\u0161imli, \u017ee rotuje i tlakov\u00e1 v\u00fd\u0161e, ov\u0161em v opa\u010dn\u00e9m smyslu a tak vznikl n\u00e1zev anticykl\u00f3na jako ozna\u010den\u00ed tlakov\u00e9 v\u00fd\u0161e.<\/p>\n

Studen\u00e1 fronta m\u00e1 mnohem rychlej\u0161\u00ed postup ne\u017e fronta tepl\u00e1 a tak p\u0159es st\u00e1dium rozvinut\u00e9 cykl\u00f3ny<\/b>dosp\u011bjeme do okam\u017eiku, kdy se za\u010dne uzav\u00edrat tepl\u00fd sektor cykl\u00f3ny, proto\u017ee studen\u00e1 fronta teplou dostihne. A v tomto okam\u017eiku v\u011bt\u0161inou \u017eivotn\u00ed cyklus cykl\u00f3ny kon\u010d\u00ed, proto\u017ee do sv\u00e9ho z\u00e1v\u011bre\u010dn\u00e9ho st\u00e1dia, do st\u00e1dia okludovan\u00e9 cykl\u00f3ny<\/b>. V tuto chv\u00edli ji\u017e na konci okluzn\u00ed fronty jsou minim\u00e1ln\u00ed rozd\u00edly mezi vzduchem p\u0159ed a za frontou, fronta se za\u010d\u00edn\u00e1 rozpadat a tlakov\u00e1 n\u00ed\u017ee vypl\u0148ovat. <\/b>Za ur\u010dit\u00fdch podm\u00ednek m\u016f\u017ee doj\u00edt k jevu, kter\u00fd naz\u00fdv\u00e1me regenerace cykl\u00f3ny. V\u011bt\u0161inou k n\u011bmu dojde t\u00edm, \u017ee se za\u010dne studen\u00e1 fronta vlnit n\u011bkde d\u00e1le od st\u0159edu p\u016fvodn\u00ed tlakov\u00e9 n\u00ed\u017ee a n\u011bkdy tak na v\u00fdrazn\u00e9 front\u011b m\u016f\u017ee vzniknout i cel\u00e1 s\u00e9rie cykl\u00f3n. Tato situace nast\u00e1v\u00e1 nej\u010dast\u011bji na ja\u0159e nebo na podzim.[\/vc_column_text][\/vc_column][\/vc_row]\n<\/div>","protected":false},"excerpt":{"rendered":"

[vc_row][vc_column][vc_column_text disable_pattern=”false”]Podstata vzniku front Atmosf\u00e9rick\u00e9 fronty vznikaj\u00ed na rozhran\u00ed dvou vzduchov\u00fdch hmot. Nejprve si mus\u00edme objasnit term\u00edn vzduchov\u00e1 hmota. Je to mno\u017estv\u00ed vzduchu, lidoveck\u00fdm term\u00ednem \u0159e\u010deno v\u011bt\u0161\u00ed ne\u017e velk\u00e9, tedy horizont\u00e1ln\u011b stovky a\u017e tis\u00edce kilometr\u016f, kter\u00e9 se del\u0161\u00ed dobu nal\u00e9z\u00e1 nad zemsk\u00fdm povrchem s ur\u010ditou charakteristikou a tuto charakteristiku od zemsk\u00e9ho povrchu p\u0159eb\u00edr\u00e1. Vzduchov\u00e9 hmoty […]<\/p>\n","protected":false},"author":7,"featured_media":0,"parent":57194,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_tribe_blocks_recurrence_rules":"","_tribe_blocks_recurrence_exclusions":"","_tribe_blocks_recurrence_description":"","footnotes":""},"class_list":["post-57212","page","type-page","status-publish","hentry"],"yoast_head":"\nAtmosf\u00e9rick\u00e9 fronty — El Speedo<\/title>\n<meta name=\"description\" content=\"El Speedo je nejv\u011bt\u0161\u00ed paraglidingov\u00e1 komunita a \u0161kola v \u010cR. 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