Njengoba sazi, imvula yinto ejwayelekile yezulu emhlabeni wethu. Akuyona into ngaphandle kokuwa kwezinhlayiya zamanzi ezifweni eziwuketshezi, umkhiqizo wokujiyanisa nokupholisa umusi wamanzi emafwini phezulu kwetroposphere. Izimvula kwesinye isikhathi kubhekiselwa kuzo njengemvula, yize lokhu kubhekisa esigabeni esibanzi kakhulu. Ukukhiqizwa kwemvula kuncike ezintweni eziningana: izinga lokushisa, ingcindezi yasemkhathini kanye nomswakama. I- Izimvula ezinkulu yilezo ezenzeka ngamandla amakhulu nangesikhathi esifushane. Kunemibuzo eminingi ngalolu hlobo lwemvula nokuthi ingaqala kanjani.
Ngakho-ke, sizonikezela le ndatshana ukukutshela konke odinga ukukwazi ngezimvula ezinamandla, izici zazo nokuthi zakha kanjani.
Imvelaphi yemvula
Ukuze sazi izici nemvelaphi yemvula enamandla, kufanele siqonde ukuthi imvula iqala kanjani. Imvula ayilutho nje oluyingxenye yomjikelezo wamanzi lapho amathonsi amanzi egeleza khona futhi phambilini abenziwe olwandle, imifula, amachibi kanye nobuso bomhlaba lapho kunamanzi khona.
Imvula yakha phakathi kokuhlukahlukene izinhlobo zamafu ezifana ne-cumuloninbus ne-nimbostratus. Lawa amafu athola umswakama omkhulu ovela emkhathini. Lapho umhwamuko wamanzi ukhuphuka futhi ufinyelela phezulu, imvamisa kuyizindawo ezibandayo. Lokhu kubangela ukuthi umusi ujiye futhi amafomu wamanzi abulelwe ukubonga nge-hygroscopic condensation nuclei. Lezi zinhlayiyana ze-condensation zingaba izinhlayiya zothuli noma izinhlayiya ezimisiwe ezitholakala emkhathini. Lapho zijija zifinyelela isisindo lapho zigcina zinciphise isenzo samandla adonsela phansi.
Ukwakheka kwemvula kungenzeka ngezindlela ezi-3:
- Imvula ye-Convection: yilezo zinhlobo zemvula lapho umoya oshisayo uhlangana khona nobuso bomhlaba bese ufudunyezwa isenzo selanga. Uma iphakama emoyeni, iyaphola futhi imvula yenzeka ngenxa yokuncipha kwamaconsi amanzi.
- Izimvula ze-Orographic: yilawo akhiwa lapho inqwaba yomoya onomswakama ishayisana nempumuzo yezintaba. Lo moya uvame ukukhuphuka emthambekeni futhi ukhiphe wonke umswakama wawo uze wehle womile ngokuphelele uye kolunye uhlangothi lwentaba.
- Imvula engaphambili: Akhiqizwa ukungqubuzana kwezixuku zomoya ezinomswakama ezinamazinga okushisa ahlukene. Imvamisa kuba yimfanelo eyodwa bese enye ibanda. Lezi zimvula ngokuvamile ziwuhlobo lwesiphepho noma lwesiphepho.
- Izimvula ezinkulu: akhiwa ngokungafani kwamazinga okushisa nobuso bomhlaba. Kuvamise ukwenzeka ekupheleni kwehlobo futhi ziyiziphepho ezinamandla amakhulu okuvame ukudala umonakalo omkhulu, ikakhulukazi kwezolimo.
Ukwakheka kwezimvula ezinamandla
Abantu abaningi bayazibuza ukuthi kungani imvula enamandla iba ngasekupheleni kwehlobo. Kujwayelekile ukuthi ezinsukwini zokugcina zika-Agasti kuba neziphepho engxenyeni enhle yezwe lethu. Futhi ngukuthi imvelaphi yalezi zimvula ezinamandla idalwa ukungazinzi. Ukungazinzi kuvame ukugxila eningizimu-mpumalanga yenhlonhlo ngemvula eningi kakhulu eyeqa ama-200 mm.
Lezi ziqephu zemvula enamandla zivame ukwaziwa ngokubizwa ngokuthi yi-droplet ebandayo. Inesizungu cishe njalo ngonyaka endaweni ezungeze uLwandle iMedithera nangalesi sikhathi. Imvamisa ziyahlukahluka phakathi kwezinsuku zokugcina zika-Agasti kanye namasonto okuqala ka-Okthoba. Imvamisa inyanga kaSepthemba yiyona enamathuba amaningi okwakheka kwawo. Zonke lezi zivunguvungu ezinzima ezenzeka njalo ngosuku olufanayo azihambelani nokuqondana, kodwa nezici ezithile zezulu.
Isizathu esiyinhloko sokuvela kwemvula enamandla ukungafani kwamazinga okushisa. Esinye sezizathu eziyinhloko ukuthi izinga lokushisa eliphakeme loLwandle iMedithera ekupheleni kwehlobo kuqhathanisa nezinsuku zobuso bomhlaba wenhlonhlo. Ekupheleni kwehlobo izinga lokushisa koLwandle iMedithera cishe ngama-27 degrees, yize kukhona amanye amarekhodi okushisa afinyelele kuma-31 degrees.
Ngakolunye uhlangothi, kufanele sikhumbule ukuthi ihlobo yisikhathi esinokuzinza okukhulu komkhathi ezweni lethu. Ukuvakashelwa kwesiphepho ezinyangeni zasehlobo akuvamile kakhulu. Kodwa-ke, ekupheleni kwalesi sikhathi izivunguvungu zenyakatho yezwe ziqala ukuvuka futhi zifike phakathi nenyanga kaSepthemba.
IDANA lidala ukuthi kube nemvula enamandla
Uma sikhuluma nge-DANA kusho ukucindezeleka okuhlukanisiwe emazingeni aphezulu. Lokhu kulingana nalokho esivame ukubiza ngokuthi iphakethe lomoya elibandayo ekuphakameni. Lapho lokhu kucindezeleka ekuphakameni kuqukethe umoya obandayo kakhulu emazingeni aphezulu womkhathi kodwa ngaphandle kokunikela komoya obandayo ngaphezulu, Itholakala eduze koLwandle iMedithera. Njengoba sinamazinga okushisa aphakeme impela lapha, kungalezi zinsuku, sinomehluko omkhulu emazingeni okushisa phakathi kwezingqimba ezahlukahlukene zomkhathi.
Lo mehluko emazingeni okushisa uphawula ukungazinzi komkhathi lapho sibona khona ukuthi izindimbane zomoya zikhuphuka ngokukhulu ukukhululeka, zigcwala ngokushesha umhwamuko wamanzi lapho zihlangana nomoya obandayo futhi zidala izivunguvungu ezinamandla. Njengoba sazi, lapho umoya oshisayo ukhuphukela ngasengxenyeni engenhla yomkhathi sithola ukufinyela okusheshayo kwamaconsi amanzi. Uma lokhu kufingqana kwenzeka ngejubane elikhulu, isiphepho siyoba nodlame olukhulu kakhulu.
Ngaphezu kwalokhu esesikushilo, uma lokhu kucindezelwa ekuphakameni kutholakala endaweni efanele futhi kufinyelela ekunikeleni komoya walesi sakhi, uma singeza kulokho okubangela inani elikhulu lomswakama ovela oLwandle iMedithera, Kwaba nesimo esikhethekile semvula enamandla. Yizimvula ezingadlula ku-300 mm. Kunerekhodi elabekwa ngo-1987 esifundeni sase ILa Safor enemvula engama-500 mm edalwe yimvula enamandla.
Ngiyethemba ukuthi ngalolu lwazi ungafunda kabanzi ngezimvula ezinkulu.