{"id":7337,"date":"2019-12-16T12:08:13","date_gmt":"2019-12-16T11:08:13","guid":{"rendered":"https:\/\/www.vtei.cz\/?p=7337"},"modified":"2024-07-17T09:41:07","modified_gmt":"2024-07-17T08:41:07","slug":"vlastnosti-umele-generovanych-srazek-vyuzivanych-pro-studium-eroze-pudy","status":"publish","type":"post","link":"https:\/\/www.vtei.cz\/en\/2019\/12\/vlastnosti-umele-generovanych-srazek-vyuzivanych-pro-studium-eroze-pudy\/","title":{"rendered":"Characterization of an artificially generated rainfall used for a soil erosion research"},"content":{"rendered":"

This article is available in Czech only. For translation or more information on this topic, please contact author.<\/h4>\n

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Souhrn<\/h2>\n

Vodn\u00ed eroze p\u016fdy se b\u011b\u017en\u011b studuje v\u00a0laborato\u0159\u00edch, experimenty b\u00fdvaj\u00ed zalo\u017eeny na um\u011ble generovan\u00fdch sr\u00e1\u017ek\u00e1ch s\u00a0vyu\u017eit\u00edm de\u0161\u0165ov\u00fdch simul\u00e1tor\u016f. Typicky je vyhodnocov\u00e1n vliv r\u016fzn\u00fdch faktor\u016f, jako jsou intenzita nebo \u00fahrn sr\u00e1\u017eky, p\u016fdn\u00ed charakteristiky, zpracov\u00e1n\u00ed p\u016fdy, poskliz\u0148ov\u00e9 zbytky nebo sklon a\u00a0d\u00e9lka erozn\u00ed plochy na erozi. V\u00fdsledky experiment\u016f slou\u017e\u00ed pro lep\u0161\u00ed pochopen\u00ed erozn\u00edch proces\u016f, odhad transportovan\u00e9ho sedimentu v\u00a0krajin\u011b nebo kalibraci matematick\u00fdch simula\u010dn\u00edch model\u016f. Vzhledem k\u00a0tomu, \u017ee eroze je iniciov\u00e1na de\u0161\u0165ovou sr\u00e1\u017ekou, je pro p\u0159enositelnost v\u00fdsledk\u016f z\u00a0laborato\u0159e do krajiny z\u00e1sadn\u00ed, aby se simulovan\u00e1 sr\u00e1\u017eka co nejv\u00edce bl\u00ed\u017eila charakteristik\u00e1m p\u0159\u00edrodn\u00edch sr\u00e1\u017eek. Intenzita de\u0161t\u011b se kontroluje pom\u011brn\u011b snadno, ale kl\u00ed\u010dov\u00fd dopad na erozn\u00ed procesy m\u00e1 kinetick\u00e1 energie de\u0161t\u011b. C\u00edlem tohoto p\u0159\u00edsp\u011bvku je komplexn\u00ed vyhodnocen\u00ed charakteristik simulovan\u00e9ho de\u0161t\u011b a\u00a0porovn\u00e1n\u00ed jeho kinetick\u00e9 energie s\u00a0energi\u00ed p\u0159\u00edrodn\u00edch sr\u00e1\u017eek. Sou\u010d\u00e1st\u00ed v\u00fdsledk\u016f je i\u00a0porovn\u00e1n\u00ed n\u011bkolika b\u011b\u017en\u011b vyu\u017e\u00edvan\u00fdch disdrometr\u016f a\u00a0diskuse vyu\u017eitelnosti disdrometr\u016f pro charakterizaci simulovan\u00fdch sr\u00e1\u017eek.<\/p>\n\"\"<\/a>\n

Experiment byl proveden na laboratorn\u00edm de\u0161\u0165ov\u00e9m simul\u00e1toru Fakulty stavebn\u00ed \u010cVUT v\u00a0Praze. Kinetick\u00e1 energie de\u0161t\u011b o\u00a0r\u016fzn\u00fdch intenzit\u00e1ch byla monitorov\u00e1na pomoc\u00ed disdrometr\u016f LPM (Thies Clima), Parsivel (OTT) a\u00a0PWS100 (Campbell Sci.), za referen\u010dn\u00ed \u00fadaj intenzity sr\u00e1\u017eky byla pova\u017eov\u00e1na data z\u00a0p\u0159eklopn\u00e9ho sr\u00e1\u017ekom\u011bru MR3 (Meteoservis). Intenzitu de\u0161t\u011b m\u011b\u0159\u00ed v\u0161echny testovan\u00e9 disdrometry uspokojiv\u011b. P\u0159\u00edstroje nam\u011b\u0159ily 106 % (LPM), 79 % (Parsivel) a\u00a0116 % (PWS100) hodnoty nam\u011b\u0159en\u00e9 pomoc\u00ed p\u0159eklopn\u00e9ho sr\u00e1\u017ekom\u011bru. V\u00a0p\u0159\u00edpad\u011b m\u011b\u0159en\u00ed kinetick\u00e9 energie nebyla nastavena \u017e\u00e1dn\u00e1 referen\u010dn\u00ed hodnota, ale p\u0159\u00edstroje byly porovn\u00e1v\u00e1ny mezi sebou. LPM oproti ostatn\u00edm dv\u011bma p\u0159\u00edstroj\u016fm m\u011b\u0159\u00ed v\u00fdrazn\u011b ni\u017e\u0161\u00ed kinetickou energii, j\u00edm nam\u011b\u0159en\u00e9 hodnoty odpov\u00eddaj\u00ed v\u00a0pr\u016fm\u011bru 83 % hodnot nam\u011b\u0159en\u00fdch Parsivelem, resp. 59 % hodnot nam\u011b\u0159en\u00fdch PWS100. Nejvy\u0161\u0161\u00ed hodnoty kinetick\u00e9 energie m\u011b\u0159il PWS100. Kl\u00ed\u010dov\u00fdm z\u00e1v\u011brem je, \u017ee p\u0159\u00edvalov\u00e1 sr\u00e1\u017eka simulovan\u00e1 laboratorn\u00edm de\u0161\u0165ov\u00fdm simul\u00e1torem m\u00e1 znateln\u011b ni\u017e\u0161\u00ed kinetickou energii ne\u017e p\u0159\u00edrodn\u00ed sr\u00e1\u017eky o\u00a0shodn\u00fdch intenzit\u00e1ch.<\/p>\n

\u00davod<\/h2>\n

\u00dahrn, doba trv\u00e1n\u00ed, intenzita, p\u0159\u00edpadn\u011b \u010dasov\u00fd pr\u016fb\u011bh jsou b\u011b\u017en\u011b monitorovan\u00e9 parametry de\u0161\u0165ov\u00fdch sr\u00e1\u017eek. Nicm\u00e9n\u011b pro mnoho v\u011bdecky i\u00a0prakticky orientovan\u00fdch studi\u00ed jsou podstatn\u00e9 i\u00a0dal\u0161\u00ed charakteristiky sr\u00e1\u017eek. Nap\u0159\u00edklad pro studium eroze p\u016fdy je kl\u00ed\u010dov\u00e1 kinetick\u00e1 energie dopadaj\u00edc\u00edch kapek, kter\u00e1 rozhoduje o\u00a0m\u00ed\u0159e degradace p\u016fdn\u00edch agreg\u00e1t\u016f a\u00a0prvotn\u00ed mobilizaci p\u016fdn\u00edch \u010d\u00e1stic. Dal\u0161\u00edmi obory, pro kter\u00e9 je \u00fa\u010deln\u00e9 sledovat sr\u00e1\u017eky podrobn\u011bji, jsou d\u00e1lkov\u00fd pr\u016fzkum zem\u011b, telekomunikace (\u00fatlum mikrovlnn\u00fdch spoj\u016f), radarov\u00e1 meteorologie, m\u011bstsk\u00e1 odvodn\u011bn\u00ed (v\u011bt\u0161\u00ed kapky s\u00a0vy\u0161\u0161\u00ed kinetickou energi\u00ed snadn\u011bji uvol\u0148uj\u00ed z\u00a0chodn\u00edk\u016f a\u00a0st\u0159ech polutanty, kter\u00e9 mohou b\u00fdt d\u00e1le transportov\u00e1ny do vodn\u00edch recipient\u016f nebo \u010cOV) a\u00a0dal\u0161\u00ed [1].<\/p>\n

Pro experiment\u00e1ln\u00ed v\u00fdzkum erozn\u00edch proces\u016f se \u010dasto vyu\u017e\u00edvaj\u00ed um\u011ble generovan\u00e9 sr\u00e1\u017eky s\u00a0vyu\u017eit\u00edm laboratorn\u00edch nebo ter\u00e9nn\u00edch de\u0161\u0165ov\u00fdch simul\u00e1tor\u016f. C\u00edlem zade\u0161\u0165ovac\u00edch experiment\u016f je simulovat takov\u00fd d\u00e9\u0161\u0165, kter\u00fd m\u00e1 srovnateln\u00e9 charakteristiky s\u00a0p\u0159irozenou de\u0161\u0165ovou sr\u00e1\u017ekou. Obvykle je kontrolov\u00e1na intenzita de\u0161t\u011b, trv\u00e1n\u00ed de\u0161t\u011b (celkov\u00fd sr\u00e1\u017ekov\u00fd \u00fahrn), p\u0159\u00edpadn\u011b prostorov\u00e1 a\u00a0\u010dasov\u00e1 rovnom\u011brnost post\u0159iku. Je zn\u00e1m\u00fd fakt, \u017ee trysky vytv\u00e1\u0159\u00ed odli\u0161n\u00e9 spektrum velikost\u00ed kapek, ne\u017e m\u00e1 p\u0159\u00edrodn\u00ed d\u00e9\u0161\u0165 [2], kapky z\u00a0de\u0161\u0165ov\u00fdch simul\u00e1tor\u016f jsou obvykle men\u0161\u00ed. Vzhledem ke konstrukci v\u011bt\u0161iny ter\u00e9nn\u00edch i\u00a0laboratorn\u00edch simul\u00e1tor\u016f zpravidla kapky nedosahuj\u00ed termin\u00e1ln\u00ed p\u00e1dov\u00e9 rychlosti odpov\u00eddaj\u00edc\u00ed p\u0159\u00edrodn\u00edmu de\u0161ti. Um\u011ble generovan\u00fd d\u00e9\u0161\u0165 m\u00e1 proto typicky ni\u017e\u0161\u00ed kinetickou energii ne\u017e p\u0159\u00edrodn\u00ed sr\u00e1\u017eka se stejnou intenzitou a\u00a0dobou trv\u00e1n\u00ed, a\u00a0nutn\u011b tak vyvol\u00e1v\u00e1 jin\u00fd erozn\u00ed \u00fa\u010dinek [3, 4]. Kinetick\u00e1 energie um\u011ble generovan\u00e9ho de\u0161t\u011b, kter\u00e1 m\u00e1 fundament\u00e1ln\u00ed vliv na inicia\u010dn\u00ed f\u00e1zi eroze p\u016fdy, b\u011b\u017en\u011b b\u011bhem experiment\u016f m\u011b\u0159ena nen\u00ed.<\/p>\n

Typicky po\u017eadovan\u00fdmi parametry sr\u00e1\u017eek jsou rozli\u0161en\u00ed hydrometeor\u016f (d\u00e9\u0161\u0165, sn\u00edh, kroupy, mlha atd.), distribuce velikost\u00ed a\u00a0rychlost\u00ed kapek, kinetick\u00e1 energie de\u0161t\u011b nebo viditelnost. V\u011bt\u0161inu zm\u00edn\u011bn\u00fdch parametr\u016f lze pozorovat, m\u011b\u0159it, p\u0159\u00edpadn\u011b vypo\u010d\u00edtat i\u00a0bez slo\u017eit\u00e9ho technick\u00e9ho vybaven\u00ed. Nap\u0159\u00edklad distribuce velikost\u00ed kapek se historicky ur\u010dovala pomoc\u00ed test\u016f s\u00a0moukou [5], kdy byla po dopadu kapek do mouky manu\u00e1ln\u011b m\u011b\u0159ena plocha jejich otisku. Obdobn\u011b b\u00fdvaly de\u0161\u0165ov\u00e9 kapky zachyt\u00e1v\u00e1ny do misky s\u00a0olejem o\u00a0specifick\u00e9 viskozit\u011b a\u00a0op\u011bt manu\u00e1ln\u011b analyzov\u00e1ny. D\u00edky sv\u00e9 jednoduchosti je pro ur\u010dit\u00e9 aplikace tato metoda ob\u010das vyu\u017e\u00edv\u00e1na, by\u0165 v\u00a0m\u00edrn\u011b modifikovan\u00e9 form\u011b, i\u00a0v\u00a0sou\u010dasnosti [6]. Pro anal\u00fdzu del\u0161\u00edch \u010dasov\u00fdch \u0159ad a\u00a0monitorov\u00e1n\u00ed sr\u00e1\u017eek v\u00a0re\u00e1ln\u00e9m \u010dase v\u0161ak nejsou tyto metody vhodn\u00e9.<\/p>\n

Relativn\u011b modern\u00ed, by\u0165 u\u017e pom\u011brn\u011b roz\u0161\u00ed\u0159enou, technologi\u00ed pro automatizovan\u00e9 a\u00a0komplexn\u00ed monitorov\u00e1n\u00ed sr\u00e1\u017eek jsou disdrometry. V\u011bt\u0161inou se jedn\u00e1 o\u00a0sob\u011bsta\u010dn\u00e1 bez\u00fadr\u017ebov\u00e1 za\u0159\u00edzen\u00ed s\u00a0kontinu\u00e1ln\u00edm z\u00e1znamem po\u010dtu, efektivn\u00edho pr\u016fm\u011bru a\u00a0p\u00e1dov\u00e9 rychlosti jednotliv\u00fdch frakc\u00ed de\u0161\u0165ov\u00fdch kapek. Nej\u010dast\u011bji vyu\u017e\u00edvan\u00e9 disdrometry lze d\u011blit podle principu m\u011b\u0159en\u00ed na t\u0159i z\u00e1kladn\u00ed typy [7]: (i) elektromechanick\u00e9 disdrometry, kter\u00e9 p\u0159\u00edmo m\u011b\u0159\u00ed kinetickou energii dopadaj\u00edc\u00edch kapek na podlo\u017eku (m\u011b\u0159eny jsou mechanick\u00e9 vibrace nebo akustick\u00e1 odezva); (ii) video disdrometry (1D nebo 2D), kter\u00e9 pomoc\u00ed vysokorychlostn\u00edho CCD sn\u00edma\u010de zaznamen\u00e1vaj\u00ed tvar a\u00a0po\u010det kapek, z\u00a0\u010deho\u017e lze vypo\u010d\u00edst efektivn\u00ed pr\u016fm\u011br, p\u00e1dovou rychlost, kinetickou energii i\u00a0\u00fahel dopadu de\u0161\u0165ov\u00e9 kapky [8]; (iii) optick\u00e9 (typicky laserov\u00e9) disdrometry, kter\u00e9 m\u011b\u0159\u00ed \u00fatlum intenzity svazku rovnob\u011b\u017en\u00fdch laserov\u00fdch paprsk\u016f vlivem propad\u00e1vaj\u00edc\u00edch kapek. Na z\u00e1klad\u011b \u00fatlumu lze vypo\u010d\u00edtat po\u010det, velikost a\u00a0p\u00e1dovou rychlost kapek.<\/p>\n

Laserov\u00e9 disdrometry jsou schopny pracovat po dlouhou dobu t\u00e9m\u011b\u0159 bez obsluhy, v\u00fdstupn\u00ed data lze zpracov\u00e1vat t\u00e9m\u011b\u0159 v\u00a0re\u00e1ln\u00e9m \u010dase. Oproti p\u0159eklopn\u00fdm sr\u00e1\u017ekom\u011br\u016fm nevy\u017eaduj\u00ed \u010dast\u00e9 \u010di\u0161t\u011bn\u00ed ani kalibraci, co\u017e je p\u0159edur\u010duje i\u00a0pro monitorov\u00e1n\u00ed intenzity de\u0161t\u011b. To, spolu s\u00a0relativn\u00ed finan\u010dn\u00ed dostupnost\u00ed a\u00a0spolehlivost\u00ed, laserov\u00e9 disdrometry p\u0159edur\u010duje k\u00a0masov\u00e9mu vyu\u017e\u00edv\u00e1n\u00ed nejen v\u00a0meteorologii.<\/p>\n

V\u00a0literatu\u0159e lze dohledat v\u00fdsledky experiment\u016f a\u00a0ter\u00e9nn\u00edch monitorov\u00e1n\u00ed, kter\u00e9 maj\u00ed za c\u00edl porovnat disdrometry a\u00a0standardizovan\u00e9 metody na b\u00e1zi p\u0159eklopn\u00fdch sr\u00e1\u017ekom\u011br\u016f. Nap\u0159\u00edklad porovn\u00e1n\u00ed elektromechanick\u00e9ho disdrometru, radaru a\u00a0optick\u00e9ho disdrometru prov\u00e1d\u011bli Sarkar a\u00a0kol. [9]. Spolehlivost disdrometr\u016f s\u00a0ohledem na stanoven\u00ed intenzity de\u0161t\u011b testovali Nakaya a\u00a0kol.\u00a0[10], Lanzinger a\u00a0kol. [11], Martinez a\u00a0kol. [12], typy sr\u00e1\u017eek stanovovali Hannelore a\u00a0kol.\u00a0[13]. Pro v\u00fdzkum a\u00a0modelov\u00e1n\u00ed eroze p\u016fdy je z\u00e1sadn\u00ed informace o\u00a0kinetick\u00e9 energii kapek a\u00a0jej\u00ed funk\u010dn\u00ed z\u00e1vislosti na intenzit\u011b de\u0161t\u011b. P\u0159ehled publikovan\u00fdch vztah\u016f mezi intenzitou p\u0159irozen\u00e9ho de\u0161t\u011b a\u00a0kinetickou energi\u00ed, odvozen\u00fdch s\u00a0vyu\u017eit\u00edm disdrometr\u016f, shrnuje Angulo-Mart\u00ednez a\u00a0kol. [14]. Vzhledem k\u00a0dostupnosti disdrometr\u016f p\u0159ib\u00fdv\u00e1 literatury s\u00a0podrobn\u00fdmi charakteristikami r\u016fzn\u00fdch typ\u016f sr\u00e1\u017eek, za\u010d\u00ednaj\u00ed b\u00fdt testov\u00e1ny i\u00a0charakteristiky um\u011ble generovan\u00fdch sr\u00e1\u017eek. Av\u0161ak komparativn\u00ed studie v\u00fdstup\u016f disdrometr\u016f od r\u016fzn\u00fdch v\u00fdrobc\u016f p\u0159i monitorov\u00e1n\u00ed p\u0159irozen\u00fdch sr\u00e1\u017eek ukazuje systematicky odli\u0161n\u00e9 v\u00fdsledky [12]. To je d\u00e1no jak r\u016fzn\u00fdm principem m\u011b\u0159en\u00ed, tak rozd\u00edly v\u00a0konstruk\u010dn\u00edch a\u00a0technologick\u00fdch detailech jednotliv\u00fdch disdrometr\u016f, jako jsou nap\u0159. rozd\u00edln\u00e9 detektory intenzity z\u00e1\u0159en\u00ed, r\u016fzn\u00e9 vlnov\u00e9 d\u00e9lky laserov\u00fdch paprsk\u016f, r\u016fzn\u00e9 \u00fahly mezi detektory rozpt\u00fdlen\u00e9ho z\u00e1\u0159en\u00ed nebo jin\u00fd syst\u00e9m klasifikace velikosti kapek. Variabilita m\u011b\u0159en\u00fdch charakteristik de\u0161t\u011b byla zji\u0161t\u011bna dokonce i\u00a0p\u0159i\u00a0 pou\u017eit\u00ed stejn\u00e9ho typu p\u0159\u00edstroje, jak ukazuje na srovn\u00e1n\u00ed p\u011bti disdrometr\u016f Thies LPM Frasson a\u00a0kol. [15] nebo dvou disdrometr\u016f PWS100 [16].<\/p>\n

Ukazuje se, \u017ee b\u011bhem simulovan\u00fdch sr\u00e1\u017eek jsou \u010dasto generov\u00e1ny kapky mimo detek\u010dn\u00ed limity n\u011bkter\u00fdch disdrometr\u016f (mal\u00e9 kapky s\u00a0vysokou rychlost\u00ed), r\u016fzn\u00e9 p\u0159\u00edstroje tak m\u011b\u0159\u00ed r\u016fznou kinetickou energii. Srovn\u00e1vac\u00ed studie, kter\u00e1 by vyhodnocovala variabilitu m\u011b\u0159en\u00fdch charakteristik simulovan\u00fdch de\u0161\u0165\u016f s\u00a0vyu\u017eit\u00edm r\u016fzn\u00fdch typ\u016f disdrometr\u016f, dosud chyb\u00ed. C\u00edlem tohoto p\u0159\u00edsp\u011bvku je porovn\u00e1n\u00ed t\u0159\u00ed typ\u016f nej\u010dast\u011bji pou\u017e\u00edvan\u00fdch optick\u00fdch laserov\u00fdch disdrometr\u016f v\u00a0podm\u00ednk\u00e1ch um\u011ble generovan\u00e9ho de\u0161t\u011b. Druh\u00fdm c\u00edlem p\u0159\u00edsp\u011bvku je porovn\u00e1n\u00ed m\u011b\u0159en\u00e9 kinetick\u00e9 energie simulovan\u00fdch sr\u00e1\u017eek s\u00a0vypo\u010d\u00edtanou kinetickou energi\u00ed p\u0159\u00edrodn\u00edch sr\u00e1\u017eek.<\/p>\n

Metodika<\/h2>\n

V\u00a0laboratorn\u00edch podm\u00ednk\u00e1ch jsme uskute\u010dnili s\u00e9rii pokus\u016f s\u00a0um\u011ble generovan\u00fdm de\u0161t\u011bm o\u00a0r\u016fzn\u00fdch intenzit\u00e1ch a\u00a0opakovan\u011b jsme m\u011b\u0159ili jeho charakteristiky pomoc\u00ed t\u0159\u00ed, v\u00a0praxi b\u011b\u017en\u011b pou\u017e\u00edvan\u00fdch, disdrometr\u016f. V\u00fdsledky m\u011b\u0159en\u00e9 pomoc\u00ed disdrometr\u016f a\u00a0referen\u010dn\u00edho p\u0159eklopn\u00e9ho sr\u00e1\u017ekom\u011bru jsme porovnali. Charakteristika simulovan\u00e9ho de\u0161t\u011b byla n\u00e1sledn\u011b porovn\u00e1na s\u00a0teoretick\u00fdmi parametry p\u0159\u00edrodn\u00ed sr\u00e1\u017eky o\u00a0shodn\u00e9 intenzit\u011b. Kinetick\u00e1 energie p\u0159irozen\u00e9ho de\u0161t\u011b byla vypo\u010d\u00edt\u00e1na podle v\u00a0literatu\u0159e publikovan\u00fdch vztah\u016f.<\/p>\n

Monitorov\u00e1n\u00ed charakteristik simulovan\u00e9ho de\u0161t\u011b<\/h2>\n

Pro monitorov\u00e1n\u00ed charakteristik de\u0161t\u011b byly vyu\u017eity t\u0159i disdrometry, jako referen\u010dn\u00ed m\u011b\u0159en\u00ed byla intenzita de\u0161t\u011b m\u011b\u0159ena \u010dlunkov\u00fdm p\u0159eklopn\u00fdm sr\u00e1\u017ekom\u011brem (m\u011brn\u00e1 plocha 500 cm2<\/sup>, rozli\u0161en\u00ed 0,1 mm). V\u0161echny disdrometry jsou optick\u00e9, laserov\u00e9ho typu, m\u011b\u0159\u00ed a\u00a0zaznamen\u00e1vaj\u00ed efektivn\u00ed pr\u016fm\u011br a\u00a0p\u00e1dovou rychlost de\u0161\u0165ov\u00fdch kapek. Kapky jsou automaticky klasifikov\u00e1ny do n\u011bkolika velikostn\u00edch a\u00a0rychlostn\u00edch t\u0159\u00edd. Jednotliv\u00e9 disdrometry (LPM Thies Clima, PWS100 Campbell Sci., Parsivel OTT) se od sebe li\u0161\u00ed vlnovou d\u00e9lkou laseru, m\u011brnou plochou, rozsahem m\u011b\u0159iteln\u00fdch velikost\u00ed a\u00a0rychlost\u00ed kapek, po\u010dtem velikostn\u00edch a\u00a0rychlostn\u00edch t\u0159\u00edd (tj. rozli\u0161en\u00edm histogram\u016f). Na obr. 1<\/em> jsou pou\u017eit\u00e9 disdrometry zn\u00e1zorn\u011bny.<\/p>\n

LPM\u00a0\u2013 (Laser Precipitation Monitor)<\/h2>\n

Disdrometr Thies LPM je vyr\u00e1b\u011bn v\u00a0N\u011bmecku firmou Thies Clima, konkr\u00e9tn\u00ed p\u0159\u00edstroj je distribuov\u00e1n pod ozna\u010den\u00edm 5.4110.10.000. Tento disdrometr je velmi \u010dasto vyu\u017e\u00edv\u00e1n zejm\u00e9na p\u0159i monitorov\u00e1n\u00ed laboratorn\u00edch experiment\u016f a\u00a0ve v\u00fdzkumu erozn\u00edch proces\u016f [17]. D\u016fvody jeho \u010dast\u00e9ho vyu\u017e\u00edvan\u00ed jsou relativn\u011b mal\u00e1 velikost, jednoduchost pou\u017eit\u00ed a\u00a0interpretace v\u00fdsledk\u016f a\u00a0v\u00fdrazn\u011b ni\u017e\u0161\u00ed po\u0159izovac\u00ed cena oproti ostatn\u00edm disdrometr\u016fm.<\/p>\n

Thies LPM vyu\u017e\u00edv\u00e1 infra\u010derven\u00fd paraleln\u00ed sv\u011bteln\u00fd paprsek o\u00a0vlnov\u00e9 d\u00e9lce 786\u00a0nm, m\u011b\u0159en\u00e1 plocha u\u017eit\u00e9ho p\u0159\u00edstroje je 44,1 cm2<\/sup>. P\u0159esn\u00e1 velikost m\u011brn\u00e9 plochy se pro konkr\u00e9tn\u00ed p\u0159\u00edstroje li\u0161\u00ed a\u00a0mus\u00ed b\u00fdt upravena pomoc\u00ed korek\u010dn\u00edho koeficientu od v\u00fdrobce pro dan\u00fd v\u00fdrobek. Opomenut\u00ed korekce vede k\u00a0chybn\u00e9 charakterizaci de\u0161t\u011b [15]. Rozsah m\u011b\u0159iteln\u00fdch pr\u016fm\u011br\u016f kapek je 0,16\u20138 mm a\u00a0p\u00e1dov\u00fdch rychlost\u00ed 0,2\u201320 m.s-1<\/sup>. Podle velikosti jsou kapky t\u0159\u00edd\u011bny do 34 kategori\u00ed, podle p\u00e1dov\u00e9 rychlosti do 34 kategori\u00ed (1 156 kombinac\u00ed pr\u016fm\u011bru a\u00a0rychlosti kapky). Rozsah m\u011b\u0159iteln\u00e9 intenzity sr\u00e1\u017eky ud\u00e1van\u00fd v\u00fdrobcem je 0,001\u2013250\u00a0mm.h-1<\/sup>. Vnit\u0159n\u00ed algoritmus disdrometru rozezn\u00e1v\u00e1 typ sr\u00e1\u017eky (vodn\u00ed kapky, sn\u00edh, kroupy, mlha) [13]. Sou\u010d\u00e1st\u00ed disdrometru je software Thies LNM View, v\u00a0jeho\u017e prost\u0159ed\u00ed lze sledovat m\u011b\u0159en\u00e9 veli\u010diny, vizualizovat distribu\u010dn\u00ed funkce velikost\u00ed a\u00a0rychlost\u00ed kapek a\u00a0vypo\u010d\u00edtat dal\u0161\u00ed parametry sr\u00e1\u017eky (intenzita, pr\u016fm\u011brn\u00e1 velikost kapek, pr\u016fm\u011brn\u00e1 rychlost kapek, kinetick\u00e1 energie de\u0161t\u011b).<\/p>\n\"\"<\/a>\n

Obr. 1. Disdrometry zleva: Thies LPM, PWS100, Parsivel
\nFig. 1. Tested disdrometers (from left): Thies LPM, PWS100, Parsivel<\/h6>\n

PWS100\u00a0\u2013 (Present Weather Sensor)<\/h2>\n

PWS100 je distribuov\u00e1n firmou Campbell Scientific (Velk\u00e1 Brit\u00e1nie), standardn\u011b jako sou\u010d\u00e1st velk\u00fdch meteorologick\u00fdch stanic. Optick\u00fd disdrometr vyu\u017e\u00edv\u00e1 paprsek v\u00a0IR spektru o\u00a0vlnov\u00e9 d\u00e9lce 830 nm, m\u011b\u0159en\u00e1 oblast je 40 cm2<\/sup>. Rozsah m\u011b\u0159iteln\u00fdch pr\u016fm\u011br\u016f kapek je 0,1\u201330 mm a\u00a0p\u00e1dov\u00fdch rychlost\u00ed 0,16\u201330 m.s-1<\/sup>. Podle velikosti jsou kapky t\u0159\u00edd\u011bny do 22 kategori\u00ed, podle p\u00e1dov\u00e9 rychlosti do 20 kategori\u00ed (440 kombinac\u00ed pr\u016fm\u011bru a rychlosti kapky). Rozsah m\u011b\u0159iteln\u00e9 intenzity sr\u00e1\u017eky ud\u00e1van\u00e1 v\u00fdrobcem je 0\u2013999,9 mm.h-1<\/sup> s\u00a0rozli\u0161en\u00edm 0,0001 mm. Data z\u00a0disdrometru jsou zaznamen\u00e1v\u00e1na dataloggerem a\u00a0ukl\u00e1d\u00e1na na SD kartu.<\/p>\n

Parsivel<\/h2>\n

Parsivel je vyr\u00e1b\u011bn spole\u010dnost\u00ed OTT (N\u011bmecko). V\u00a0sou\u010dasnosti je v\u00a0distribuci u\u017e druh\u00e1 generace disdrometru pod ozna\u010den\u00edm Parsivel2<\/sup>, kter\u00e1 m\u00e1 m\u00edrn\u011b odli\u0161n\u00e9 charakteristiky a\u00a0v\u00a0r\u00e1mci t\u00e9to studie nebyla testov\u00e1na. Parsivel prvn\u00ed generace vyu\u017e\u00edv\u00e1 paprsek o\u00a0vlnov\u00e9 d\u00e9lce 650 nm, monitorovan\u00e1 plocha je 54 cm2<\/sup> (180\u00a0\u00d7\u00a030 mm). Rozsah m\u011b\u0159iteln\u00fdch pr\u016fm\u011br\u016f kapek je 0,2\u20135 mm (pevn\u00e9 \u010d\u00e1stice do 25 mm) a\u00a0p\u00e1dov\u00fdch rychlost\u00ed 0,2\u201320 m.s-1<\/sup>. Podle velikosti jsou kapky t\u0159\u00edd\u011bny do 32 kategori\u00ed, podle p\u00e1dov\u00e9 rychlosti do 30 kategori\u00ed (1 024 kombinac\u00ed pr\u016fm\u011bru a\u00a0rychlosti kapky). Rozsah m\u011b\u0159iteln\u00e9 intenzity sr\u00e1\u017eky ud\u00e1van\u00e1 v\u00fdrobcem je 0,001\u20131 200 mm.h-1<\/sup>. Obdobn\u011b jako Thies LPM byl Parsivel p\u0159ipojen k\u00a0PC se spu\u0161t\u011bn\u00fdm programem pro z\u00e1znam a\u00a0vyhodnocen\u00ed charakteristik de\u0161t\u011b.<\/p>\n

Simulace de\u0161t\u011b<\/h2>\n

Pro simulaci sr\u00e1\u017eky byl pou\u017eit laboratorn\u00ed tryskov\u00fd de\u0161\u0165ov\u00fd simul\u00e1tor typu Norton Ladder, um\u00edst\u011bn\u00fd ve vodohospod\u00e1\u0159sk\u00e9 laborato\u0159i Fakulty stavebn\u00ed \u010cVUT v\u00a0Praze [18]. Simul\u00e1tor je osazen osmi kyvn\u00fdmi tryskami Veejet 80100 ve dvou \u0159ad\u00e1ch, kter\u00e9 pracuj\u00ed p\u0159i vodn\u00edm tlaku 41 kPa [19]. Trysky jsou neust\u00e1le otev\u0159en\u00e9, intenzita de\u0161t\u011b na plo\u0161e pod tryskami je regulov\u00e1na nastaven\u00edm frekvence kyv\u016f trysek a\u00a0d\u00e9lkou prodlevy mezi jednotliv\u00fdmi kyvy. P\u00e1dov\u00e1 v\u00fd\u0161ka kapek je 2,6 m, simul\u00e1tor je vhodn\u00fd pro pou\u017eit\u00ed p\u0159i intenzit\u011b 20\u201380 mm.h-1<\/sup>. B\u011b\u017en\u011b u\u017e\u00edvan\u00e1 experiment\u00e1ln\u00ed plocha pro zade\u0161\u0165ov\u00e1n\u00ed m\u00e1 rozm\u011br 1\u00a0\u00d7\u00a04 m, teoreticky lze vyu\u017e\u00edt prostor o\u00a0rozm\u011brech p\u0159ibli\u017en\u011b 1,5\u00a0\u00d7\u00a06 m.<\/p>\n

Pro testov\u00e1n\u00ed disdrometr\u016f jsme vyu\u017eili skute\u010dnosti, \u017ee rozlo\u017een\u00ed intenzity sr\u00e1\u017eky nen\u00ed v\u00a0plo\u0161e pod tryskami simul\u00e1toru zcela rovnom\u011brn\u00e9, na okraj\u00edch experiment\u00e1ln\u00ed plochy m\u00e1 d\u00e9\u0161\u0165 ni\u017e\u0161\u00ed intenzitu, p\u0159\u00edmo pod tryskami vysokou intenzitu. Pod de\u0161\u0165ov\u00fdm simul\u00e1torem bylo vytipov\u00e1no osm pozic s\u00a0rozd\u00edlnou intenzitou simulovan\u00e9ho de\u0161t\u011b v\u00a0rozmez\u00ed cca 20\u201380 mm.h-1<\/sup> (obr. 2<\/em>). Na tyto pozice byly v\u00a0pr\u016fb\u011bhu simulovan\u00e9 sr\u00e1\u017eky opakovan\u011b umis\u0165ov\u00e1ny testovan\u00e9 disdrometry a\u00a0sr\u00e1\u017ekom\u011br tak, \u017ee v\u017edy geometrick\u00fd st\u0159ed m\u011brn\u00e9 oblasti konkr\u00e9tn\u00edho disdrometru byl nad stejn\u00fdm bodem. Disdrometry byly orientov\u00e1ny rovnob\u011b\u017en\u011b s\u00a0hlavn\u00edm ramenem de\u0161\u0165ov\u00e9ho simul\u00e1toru. Mimo disdrometry a\u00a0sr\u00e1\u017ekom\u011bru byly pro kontrolu na vytipovan\u00fdch pozic\u00edch rozm\u00edst\u011bny odm\u011brn\u00e9 n\u00e1doby s\u00a0definovanou sb\u011brnou plochou (sr\u00e1\u017ekov\u00fd totaliz\u00e1tor).<\/p>\n\"\"<\/a>\n

Obr. 2. Rozlo\u017een\u00ed disdrometr\u016f s\u00a0\u010d\u00edseln\u00fdm ozna\u010den\u00edm pozice, \u010derven\u011b je nazna\u010dena pozice trysek
\nFig. 2. The tested positions under the rainfall simulator, red rectangles represent the nozzles<\/h6>\n

P\u0159emis\u0165ov\u00e1n\u00ed jednotliv\u00fdch disdrometr\u016f a\u00a0sr\u00e1\u017ekom\u011bru mezi vytipovan\u00fdmi pozicemi bylo prov\u00e1d\u011bno bez p\u0159eru\u0161ov\u00e1n\u00ed simulace de\u0161t\u011b, aby nedoch\u00e1zelo k\u00a0tlakov\u00fdm r\u00e1z\u016fm v\u00a0syst\u00e9mu simul\u00e1toru, a\u00a0tak kol\u00eds\u00e1n\u00ed intenzity sr\u00e1\u017eky. V\u0161echny p\u0159\u00edstroje zaznamen\u00e1valy \u00fadaje v\u00a0minutov\u00e9m kroku, na ka\u017ed\u00e9 pozici byly um\u00edst\u011bny 30 minut. Pro vyhodnocen\u00ed bylo vyu\u017eito monitorov\u00e1n\u00ed ze st\u0159edn\u00edch 24\u00a0minut.<\/p>\n

Kinetickou energii de\u0161t\u011b lze vztahovat na ur\u010dit\u00fd \u010dasov\u00fd \u00fasek KER<\/sub> (J.m-2<\/sup>.h-1<\/sup>), nebo na ur\u010dit\u00fd sr\u00e1\u017ekov\u00fd \u00fahrn KE (J.m-2<\/sup>.mm-1<\/sup>). Prvn\u00ed p\u0159\u00edpad obecn\u011b charakterizuje kinetickou energii konkr\u00e9tn\u00ed sr\u00e1\u017ekov\u00e9 ud\u00e1losti, kter\u00e1 mohla m\u00edt v \u010dase prom\u011bnlivou intenzitu. Druh\u00fd p\u0159\u00edpad charakterizuje typ sr\u00e1\u017eky. Literatura uv\u00e1d\u00ed (nap\u0159. [20]), \u017ee samotn\u00e1 intenzita de\u0161t\u011b nemus\u00ed m\u00edt v\u00fdznamn\u00fd vliv na distribuci velikost\u00ed kapek. Av\u0161ak distribuce velikost\u00ed kapek je odli\u0161n\u00e1 pro r\u016fzn\u00fd typ nebo lokalitu sr\u00e1\u017eky (nap\u0159. konvektivn\u00ed vs. stratiformn\u00ed, nebo kontinent\u00e1ln\u00ed vs. p\u0159\u00edmo\u0159sk\u00e1 oblast). Pro porovn\u00e1n\u00ed disdrometr\u016f jsme pou\u017eili oba zp\u016fsoby vyj\u00e1d\u0159en\u00ed kinetick\u00e9 energie.<\/p>\n

Intenzita sr\u00e1\u017eky a\u00a0kinetick\u00e1 energie sr\u00e1\u017eky pro ka\u017ed\u00fd minutov\u00fd \u00fasek byla vypo\u010d\u00edt\u00e1na z\u00a0m\u011b\u0159en\u00e9 distribuce kapek a\u00a0jejich rychlost\u00ed podle vztah\u016f:<\/p>\n\"\"<\/a>\n\"\"<\/a>\n\"\"<\/a>\n\n\n\n\n\n\n\n\n\n\n
kde<\/td>\n\u00a0 I<\/em><\/td>\nje<\/td>\nintenzita sr\u00e1\u017eky (mm.h-1<\/sup>),<\/td>\n<\/tr>\n
<\/td>\nA<\/em><\/td>\n<\/td>\nm\u011brn\u00e1 plocha laserov\u00e9ho paprsku disdrometru (m2<\/sup>),<\/td>\n<\/tr>\n
<\/td>\nt<\/em><\/td>\n<\/td>\ndoba sb\u011bru dat (s),<\/td>\n<\/tr>\n
<\/td>\nKE<\/em><\/td>\n<\/td>\nkinetick\u00e1 energie (J.m2<\/sup>.h-1<\/sup>),<\/td>\n<\/tr>\n
<\/td>\nKE<\/em>R\u00a0<\/sub><\/td>\n<\/td>\nkinetick\u00e1 energie (J.m2<\/sup>.h-1<\/sup>),<\/td>\n<\/tr>\n
<\/td>\n N<\/em><\/td>\n<\/td>\npo\u010det kapek v\u00a0kategorii (-),<\/td>\n<\/tr>\n
<\/td>\nD<\/em><\/td>\n<\/td>\npr\u016fm\u011br kapky (mm),<\/td>\n<\/tr>\n
<\/td>\nV<\/em>D<\/sub><\/td>\n<\/td>\nrychlost kapky o\u00a0pr\u016fm\u011bru D<\/em> (m.s-1<\/sup>).<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

 <\/p>\n

V\u00fdsledky<\/h2>\n

Pr\u016fm\u011brn\u00e9 hodnoty intenzity a\u00a0kinetick\u00e9 energie na jednotliv\u00fdch pozic\u00edch jsou uvedeny v\u00a0tabulce 1<\/em> a\u00a0zn\u00e1zorn\u011bny na obr. 4<\/em>. Jde v\u017edy o\u00a0pr\u016fm\u011br z\u00a0trojice osmi minutov\u00fdch interval\u016f (celkem 24 hodnot) m\u011b\u0159en\u00fdch pomoc\u00ed jednotliv\u00fdch disdrometr\u016f.<\/p>\n\"\"<\/a>\n

Obr. 3. Distribuce velikosti kapek p\u0159i intenzit\u011b 62 mm.h-1<\/sup> zaznamenan\u00e9 jednotliv\u00fdmi disdrometry
\nFig. 3. Drop size distribution at the rainfall intensity of 62 mm.h-1 <\/sup>as recorded by different disdrometers<\/h6>\n

Jak bylo uvedeno, kinetick\u00e1 energie je dopo\u010d\u00edt\u00e1v\u00e1na z\u00a0informac\u00ed o\u00a0mno\u017estv\u00ed a\u00a0velikosti de\u0161\u0165ov\u00fdch kapek. Z\u00a0obr. 3<\/em> je patrn\u00e9, \u017ee disdrometry detekuj\u00ed r\u016fzn\u00e9 po\u010dty kapek, a\u00a0to p\u0159edev\u0161\u00edm t\u011bch mal\u00fdch. Thies LPM zaznamen\u00e1v\u00e1 pro mal\u00e9 kategorie mnohem v\u00edce kapek, ne\u017e oba ostatn\u00ed disdrometry. Pro kapky s\u00a0efektivn\u00edm pr\u016fm\u011brem pod 0,5\u00a0mm dokonce minutov\u00e1 mno\u017estv\u00ed p\u0159esahuj\u00ed 5\u00a0000\u00a0mikrokapek. Pro hodnoty nad 1\u00a0mm jsou ji\u017e po\u010dty kapek pro v\u0161echny disdrometry obdobn\u00e9. M\u00edrn\u00e9 rozd\u00edly lze o\u010dek\u00e1vat, proto\u017ee ka\u017ed\u00fd disdrometr m\u00e1 jinou pr\u016fletovou plochu a\u00a0jinak uspo\u0159\u00e1dan\u00e9 velikostn\u00ed t\u0159\u00eddy. Av\u0161ak v\u00a0relativn\u00edm m\u011b\u0159\u00edtku by distribu\u010dn\u00ed funkce m\u011bly vypadat podobn\u011b.<\/p>\n

Disdrometry se v\u00a0praxi vyu\u017e\u00edvaj\u00ed zejm\u00e9na na monitorov\u00e1n\u00ed intenzity de\u0161t\u011b. Z\u00a0porovn\u00e1n\u00ed m\u011b\u0159en\u00ed disdrometr\u016f a\u00a0sr\u00e1\u017ekom\u011bru na pozic\u00edch s\u00a0r\u016fznou intenzitou de\u0161t\u011b plyne, \u017ee testovan\u00e9 p\u0159\u00edstroje ud\u00e1vaj\u00ed srovnateln\u00e9 v\u00fdsledky. P\u0159\u00edstroje nam\u011b\u0159ily 106 % (LPM), 78 % (Parsivel) a\u00a0116 % (PWS100), hodnoty nam\u011b\u0159en\u00e9 pomoc\u00ed p\u0159eklopn\u00e9ho sr\u00e1\u017ekom\u011bru. V\u00a0p\u0159\u00edpad\u011b m\u011b\u0159en\u00ed kinetick\u00e9 energie nebyla nastavena \u017e\u00e1dn\u00e1 referen\u010dn\u00ed hodnota, ale p\u0159\u00edstroje byly porovn\u00e1v\u00e1ny mezi sebou.<\/p>\n

Tabulka 1. Pr\u016fm\u011brn\u00e9 hodnoty pro jednotliv\u00e9 disdrometry na testovan\u00fdch pozic\u00edch
\nTable 1. Average values of the kinetic energy and rainfall intensity recorded at the tested positions<\/h5>\n\"\"<\/a>\n

LPM oproti ostatn\u00edm dv\u011bma p\u0159\u00edstroj\u016fm m\u011b\u0159\u00ed v\u00fdrazn\u011b ni\u017e\u0161\u00ed kinetickou energii, j\u00edm nam\u011b\u0159en\u00e9 hodnoty odpov\u00eddaj\u00ed v\u00a0pr\u016fm\u011bru 83 % hodnot nam\u011b\u0159en\u00fdch Parsivelem, resp. 59 % hodnot nam\u011b\u0159en\u00fdch PWS100. Nejvy\u0161\u0161\u00ed hodnoty m\u011b\u0159il PWS100. Parsivel m\u011b\u0159il pr\u016fm\u011brn\u011b 74 % hodnot nam\u011b\u0159en\u00fdch pomoc\u00ed PWS100 (obr. 4<\/em>).<\/p>\n\"\"<\/a>\n

Obr. 4. M\u011b\u0159en\u00e9 hodnoty intenzity (vlevo) a\u00a0kinetick\u00e9 energie de\u0161t\u011b (vpravo) na vybran\u00fdch testovan\u00fdch pozic\u00edch pod de\u0161\u0165ov\u00fdm simul\u00e1torem
\nFig. 4. Recorded rainfall intensity (left) and rainfall kinetic energy (right) on selected positions<\/h6>\n

Na obr. 5<\/em> je vynesena z\u00e1vislost mezi intenzitou simulovan\u00e9 sr\u00e1\u017eky a\u00a0m\u011b\u0159enou kinetickou energi\u00ed. Body na grafu vyjad\u0159uj\u00ed pr\u016fm\u011brn\u00e9 m\u011b\u0159en\u00e9 hodnoty zachycen\u00e9 t\u0159emi disdrometry. Data vykazuj\u00ed line\u00e1rn\u00ed z\u00e1vislost. Disdrometry Parsivel a\u00a0PSW100 maj\u00ed velice podobn\u00fd trend se sm\u011brnic\u00ed 18,804 a\u00a018,21 a\u00a0 koeficienty determinace 0,955 a\u00a00,957. LPM vykazuje tak\u00e9 line\u00e1rn\u00ed z\u00e1vislost s\u00a0 koeficientem determinace 0,683, ale v\u00a0porovn\u00e1n\u00ed s\u00a0ostatn\u00edmi p\u0159\u00edstroji ni\u017e\u0161\u00ed sm\u011brnic\u00ed 10,908. Oproti zb\u00fdvaj\u00edc\u00edm disdrometr\u016fm m\u011b\u0159\u00ed LPM v\u00fdrazn\u011b ni\u017e\u0161\u00ed kinetickou energii, a\u00a0to zejm\u00e9na p\u0159i vysok\u00fdch intenzit\u00e1ch.<\/p>\n

Na grafu jsou vyneseny i\u00a0teoretick\u00e9 z\u00e1vislosti mezi intenzitou p\u0159irozen\u00e9ho de\u0161t\u011b a\u00a0kinetickou energi\u00ed. Tyto empirick\u00e9 z\u00e1vislosti byly p\u0159ejaty z\u00a0literatury [21\u201324] a\u00a0jsou b\u011b\u017en\u011b vyu\u017e\u00edv\u00e1ny pro odhad kinetick\u00e9 energie p\u0159irozen\u00e9ho de\u0161t\u011b i\u00a0v\u00a0podm\u00ednk\u00e1ch kontinent\u00e1ln\u00ed Evropy (nap\u0159. [25, 26]). Z\u00a0porovn\u00e1n\u00ed plyne, \u017ee kinetick\u00e1 energie simulovan\u00e9ho de\u0161t\u011b je ni\u017e\u0161\u00ed ne\u017e kinetick\u00e1 energie p\u0159irozen\u00fdch sr\u00e1\u017eek. Stejn\u00e1 skute\u010dnost je je\u0161t\u011b z\u0159eteln\u011bj\u0161\u00ed p\u0159i vynesen\u00ed kinetick\u00e9 energie na milimetrov\u00fd \u00fahrn sr\u00e1\u017eky (obr. 6<\/em>). Zat\u00edmco kinetick\u00e1 energie p\u0159irozen\u00e9ho de\u0161t\u011b s\u00a0intenzitou roste (kapky se zv\u011bt\u0161uj\u00ed), v\u00a0p\u0159\u00edpad\u011b simulovan\u00e9ho de\u0161t\u011b je kinetick\u00e1 energie konstantn\u00ed. Tedy s\u00a0prom\u011bnlivou intenzitou simulovan\u00e9ho de\u0161t\u011b se nem\u011bn\u00ed distribuce velikost\u00ed kapek ani jejich p\u00e1dov\u00e9 rychlosti\u00a0\u2013 co\u017e je d\u00e1no zp\u016fsobem regulace intenzity de\u0161t\u011b pro kyvn\u00fd de\u0161\u0165ov\u00fd simul\u00e1tor pomoc\u00ed frekvence kyv\u016f trysek.<\/p>\n

Diskuse<\/h2>\n

C\u00edlem pr\u00e1ce je srovn\u00e1n\u00ed rozd\u00edln\u00fdch disdrometr\u016f a\u00a0jejich schopnost monitorovat um\u011ble generovanou sr\u00e1\u017eku. Nen\u00ed p\u0159ekvapen\u00edm, \u017ee a\u010dkoliv testov\u00e1n\u00ed prob\u00edhalo za pe\u010dliv\u011b kontrolovan\u00fdch podm\u00ednek, v\u00fdsledky m\u011b\u0159en\u00ed jednotliv\u00fdch p\u0159\u00edstroj\u016f se li\u0161\u00ed. V\u00a0literatu\u0159e lze dohledat studie, kter\u00e9 dokonce ukazuj\u00ed variabilitu\u00a0m\u011b\u0159en\u00ed i\u00a0p\u0159i pou\u017eit\u00ed stejn\u00fdch typ\u016f disdrometr\u016f. Tapiador a\u00a0kol. [27] monitorovali p\u0159\u00edrodn\u00ed sr\u00e1\u017eky pomoc\u00ed 14 disdrometr\u016f Parsivel um\u00edst\u011bn\u00fdch na jedn\u00e9 lokalit\u011b. Variabilita v\u00a0m\u011b\u0159en\u00fdch intenzit\u00e1ch jednotliv\u00fdch disdrometr\u016f dosahovala a\u017e 70 %, co\u017e, jak uv\u00e1d\u00ed auto\u0159i, mohlo b\u00fdt d\u00e1no i\u00a0prostorovou variabilitou de\u0161t\u011b, ale tak\u00e9 systematickou odchylkou v\u00a0m\u011b\u0159en\u00ed jednotliv\u00fdmi p\u0159\u00edstroji. Testovan\u00e9 disdrometry vykazuj\u00ed velmi dobr\u00e9 v\u00fdsledky p\u0159i monitorov\u00e1n\u00ed intenzity um\u011bl\u00e9ho de\u0161t\u011b. Odchylky oproti referen\u010dn\u00edmu sr\u00e1\u017ekom\u011bru jsou srovnateln\u00e9 s\u00a0m\u011b\u0159en\u00edmi v\u00a0ter\u00e9nu, kde jsou b\u011b\u017en\u00e9 rozd\u00edly okolo 20 % [11].<\/p>\n\"\"<\/a>\n

Obr. 5. Z\u00e1vislost m\u011b\u0159en\u00fdch hodnot kinetick\u00e9 energie a\u00a0intenzity sr\u00e1\u017eky; porovn\u00e1n\u00ed se \u010dty\u0159mi publikovan\u00fdmi vztahy mezi intenzitou sr\u00e1\u017eky a\u00a0kinetickou energi\u00ed
\nFig. 5. Comparison of the observed and empirical relationships between rainfall kinetic energy and intensity<\/h6>\n

V\u011bt\u0161\u00ed odchylky mezi p\u0159\u00edstroji, a\u00a0t\u00edm i\u00a0vy\u0161\u0161\u00ed m\u00edra nejistoty jsou pozorov\u00e1ny p\u0159i vyhodnocen\u00ed kinetick\u00e9 energie de\u0161t\u011b. Zejm\u00e9na Thies LMP m\u011b\u0159\u00ed v\u00fdrazn\u011b ni\u017e\u0161\u00ed kinetickou energii oproti ostatn\u00edm p\u0159\u00edstroj\u016fm. D\u016fvodem je pravd\u011bpodobn\u011b podhodnocen\u00e1 m\u011b\u0159en\u00e1 p\u00e1dov\u00e1 rychlost kapek, proto\u017ee mno\u017estv\u00ed st\u0159edn\u00edch a\u00a0velk\u00fdch kapek je srovnateln\u00e9 s\u00a0ostatn\u00edmi disdrometry. Mno\u017estv\u00ed velmi mal\u00fdch kapek je dokonce n\u00e1sobn\u011b vy\u0161\u0161\u00ed, nicm\u00e9n\u011b nejmen\u0161\u00ed kapky maj\u00ed na celkovou kinetickou energii minim\u00e1ln\u00ed vliv. M\u011b\u0159en\u00e9 velk\u00e9 mno\u017estv\u00ed velmi mal\u00fdch kapek bylo pozorov\u00e1no i\u00a0v\u00a0ter\u00e9nn\u00edch aplikac\u00edch, jedno z\u00a0nab\u00edzen\u00fdch vysv\u011btlen\u00ed spo\u010d\u00edv\u00e1 v\u00a0samotn\u00e9 konstrukci p\u0159\u00edstroje. Kapky se mohou od \u010d\u00e1st\u00ed p\u0159\u00edstroje rozb\u00edjet a\u00a0odr\u00e1\u017eet p\u0159ed senzorem, kter\u00fd tak nezaznamen\u00e1v\u00e1 pouze sr\u00e1\u017eku, ale tak\u00e9 um\u011ble vznikaj\u00edc\u00ed mikrokapi\u010dky [12].<\/p>\n

Parsivel zaznamen\u00e1v\u00e1 rychlosti kapek velmi bl\u00edzk\u00e9 jejich termin\u00e1ln\u00edm p\u00e1dov\u00fdm rychlostem [28], m\u011b\u0159\u00ed n\u00edzk\u00fd po\u010det kapek s\u00a0men\u0161\u00edm pr\u016fm\u011brem ne\u017e 0,76 mm a\u00a0naopak velk\u00fd po\u010det kapek v\u011bt\u0161\u00edch ne\u017e 2,4 mm. Stejn\u00e9 z\u00e1v\u011bry, kter\u00e9 mohou v\u00e9st k\u00a0nadhodnocen\u00ed kinetick\u00e9 energie, p\u0159in\u00e1\u0161\u00ed Angulo-Mart\u00ednez a\u00a0Tokay a\u00a0kol. [29, 30].<\/p>\n

Z\u00a0testov\u00e1n\u00ed v\u00a0ter\u00e9nu vypl\u00fdv\u00e1, \u017ee PWS100 m\u011b\u0159\u00ed m\u00edrn\u011b vy\u0161\u0161\u00ed sr\u00e1\u017ekov\u00fd \u00fahrn a\u00a0dob\u0159e m\u011b\u0159\u00ed p\u00e1dov\u00e9 rychlosti kapek [31]. Obdobn\u00fd trend byl pozorov\u00e1n b\u011bhem na\u0161eho experimentu. I\u00a0b\u011bhem um\u011ble generovan\u00e9 sr\u00e1\u017eky PWS100 m\u011b\u0159il vy\u0161\u0161\u00ed intenzitu de\u0161t\u011b. M\u011b\u0159en\u00e9 p\u00e1dov\u00e9 rychlosti byly ni\u017e\u0161\u00ed ne\u017e termin\u00e1ln\u00ed, ale to je d\u00e1no charakteristikou simulovan\u00e9ho de\u0161t\u011b, p\u0159i kter\u00e9m maxim\u00e1ln\u00edch rychlost\u00ed nen\u00ed dosa\u017eeno.<\/p>\n

Simulovan\u00fd d\u00e9\u0161\u0165 m\u00e1 znateln\u011b ni\u017e\u0161\u00ed kinetickou energii ne\u017e p\u0159\u00edrodn\u00ed sr\u00e1\u017eky o\u00a0shodn\u00fdch intenzit\u00e1ch, k\u00a0v\u00fdznamn\u00e9 odchylce doch\u00e1z\u00ed od prahov\u00e9 intenzity p\u0159ibli\u017en\u011b 20 mm.h-1<\/sup> (obr. 6<\/em>). Je nutn\u00e9 podotknout, \u017ee tento z\u00e1v\u011br plat\u00ed jen pro de\u0161\u0165ov\u00e9 simul\u00e1tory s\u00a0podobnou konstrukc\u00ed, jak\u00e1 byla pou\u017eita v\u00a0t\u00e9to studii. Nicm\u00e9n\u011b generov\u00e1n\u00ed de\u0161t\u011b pomoc\u00ed trysek situovan\u00fdch pom\u011brn\u011b bl\u00edzko k\u00a0p\u016fdn\u00edmu povrchu je v\u00a0erozn\u00edm v\u00fdzkumu \u010dasto pou\u017e\u00edvan\u00e9 [32, 33]. Proto je velmi d\u016fle\u017eit\u00e9, aby v\u00fdsledky erozn\u00edch experiment\u016f prov\u00e1d\u011bn\u00fdch s\u00a0vyu\u017eit\u00edm de\u0161\u0165ov\u00fdch simul\u00e1tor\u016f byly dob\u0159e interpretov\u00e1ny. Nelze tvrdit, \u017ee simulovan\u00e1 sr\u00e1\u017eka vyvol\u00e1 stejn\u00fd erozn\u00ed \u00fa\u010dinek jako p\u0159\u00edrodn\u00ed sr\u00e1\u017eka o\u00a0stejn\u00e9 intenzit\u011b, nebo\u0165 kinetick\u00e1 energie simulovan\u00e9ho de\u0161t\u011b je v\u00fdznamn\u011b ni\u017e\u0161\u00ed. Ke stejn\u00fdm z\u00e1v\u011br\u016fm dosp\u011bli tak\u00e9 Petr\u016f a\u00a0Kalibov\u00e1 [34], kte\u0159\u00ed zd\u016fraz\u0148uj\u00ed nutnost kalibrace vztahu mezi intenzitou a\u00a0kinetickou energi\u00ed pro ka\u017ed\u00fd simul\u00e1tor (typ trysky).<\/p>\n\"\"<\/a>\n

Obr. 6. Z\u00e1vislost kinetick\u00e9 energie p\u0159epo\u010dten\u00e9 na milimetr sr\u00e1\u017eky na intenzit\u011b sr\u00e1\u017eky; porovn\u00e1n\u00ed se \u010dty\u0159mi publikovan\u00fdmi vztahy mezi intenzitou sr\u00e1\u017eky a\u00a0kinetickou energi\u00ed
\nFig. 6. Comparison of the observed and empirical relationships between rainfall kinetic energy per mm of rainfall and rainfall intensity<\/h6>\n

Z\u00e1v\u011br<\/h2>\n

P\u0159\u00edsp\u011bvek shrnuje v\u00fdsledky experimentu s\u00a0um\u011ble generovan\u00fdm de\u0161t\u011bm o\u00a0n\u011bkolika intenzit\u00e1ch, p\u0159i kter\u00e9m byly testov\u00e1ny a\u00a0porovn\u00e1v\u00e1ny t\u0159i nej\u010dast\u011bji pou\u017e\u00edvan\u00e9 disdrometry. Testovan\u00e9 disdrometry byly pom\u011brn\u011b spolehliv\u00e9 p\u0159i monitorov\u00e1n\u00ed intenzity de\u0161t\u011b. Stanoven\u00e1 kinetick\u00e1 energie de\u0161t\u011b pomoc\u00ed jednotliv\u00fdch disdrometr\u016f se v\u0161ak li\u0161ila. Zejm\u00e9na v\u00a0erozn\u00edch studi\u00edch nej\u010dast\u011bji pou\u017e\u00edvan\u00fd disdrometr Thies LPM m\u011b\u0159il v\u00fdrazn\u011b ni\u017e\u0161\u00ed kinetickou energii, j\u00edm nam\u011b\u0159en\u00e9 hodnoty odpov\u00eddaj\u00ed v\u00a0pr\u016fm\u011bru 78 % hodnot nam\u011b\u0159en\u00fdch Parsivelem, resp. 56 % hodnot nam\u011b\u0159en\u00fdch PWS100.<\/p>\n

D\u00e9\u0161\u0165 generovan\u00fd pomoc\u00ed tryskov\u00e9ho simul\u00e1toru m\u00e1 v\u00fdznamn\u011b ni\u017e\u0161\u00ed kinetickou energii ne\u017e p\u0159irozen\u00fd d\u00e9\u0161\u0165 o\u00a0stejn\u00e9 intenzit\u011b. Rozd\u00edl v\u00a0kinetick\u00e9 energii je v\u00fdznamn\u00fd pro sr\u00e1\u017eky o\u00a0intenzit\u011b vy\u0161\u0161\u00ed ne\u017e 20 mm.h-1<\/sup>, s\u00a0rostouc\u00ed intenzitou rozd\u00edl d\u00e1le roste. Toto m\u016f\u017ee znamenat, \u017ee experiment\u00e1ln\u011b zji\u0161t\u011bn\u00e9 parametry erozn\u00edch proces\u016f nelze, bez korekce, aplikovat v\u00a0simula\u010dn\u00edch modelech erozn\u00edch proces\u016f v\u00a0krajin\u011b.<\/p>\n

Tyto z\u00e1v\u011bry plynou z\u00a0testov\u00e1n\u00ed konkr\u00e9tn\u00edch disdrometr\u016f na jednom tryskov\u00e9m de\u0161\u0165ov\u00e9m simul\u00e1toru, nelze je proto zcela zobec\u0148ovat. Nicm\u00e9n\u011b, konstrukce de\u0161\u0165ov\u00e9ho simul\u00e1toru, pou\u017eit\u00e9 trysky i\u00a0disdrometry jsou v\u00a0erozn\u00edch laborato\u0159\u00edch b\u011b\u017en\u011b pou\u017e\u00edv\u00e1ny, z\u00e1v\u011bry jsou tak relevantn\u00ed pro v\u00fdznamnou \u010d\u00e1st odborn\u00e9 komunity.<\/p>\n

Pod\u011bkov\u00e1n\u00ed<\/h3>\n

P\u0159\u00edsp\u011bvek vznikl za podpory projektu GA17-33751L, FWF I\u00a03049-N29 a\u00a0SGS 161-1611791A143.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Vodn\u00ed eroze p\u016fdy se b\u011b\u017en\u011b studuje v laborato\u0159\u00edch, experimenty b\u00fdvaj\u00ed zalo\u017eeny na um\u011ble generovan\u00fdch sr\u00e1\u017ek\u00e1ch s vyu\u017eit\u00edm de\u0161\u0165ov\u00fdch simul\u00e1tor\u016f. Typicky je vyhodnocov\u00e1n vliv r\u016fzn\u00fdch faktor\u016f, jako jsou intenzita nebo \u00fahrn sr\u00e1\u017eky, p\u016fdn\u00ed charakteristiky, zpracov\u00e1n\u00ed p\u016fdy, poskliz\u0148ov\u00e9 zbytky nebo sklon a d\u00e9lka erozn\u00ed plochy na erozi. <\/p>\n","protected":false},"author":8,"featured_media":7132,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[86],"tags":[1747,1744,726,1746,1745],"coauthors":[1729,1730,1066,698,1731,1732,693,1734,1733],"class_list":["post-7337","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hydraulics-hydrology-and-hydrogeology","tag-destovy-simulator","tag-disdrometr","tag-eroze-pudy","tag-intenzita-deste","tag-kineticka-energie-deste"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/7337","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/comments?post=7337"}],"version-history":[{"count":4,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/7337\/revisions"}],"predecessor-version":[{"id":30558,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/7337\/revisions\/30558"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media\/7132"}],"wp:attachment":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media?parent=7337"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/categories?post=7337"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/tags?post=7337"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/coauthors?post=7337"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}