Imvula eMzantsi Afrika

© Peter Delaney
Uninzi lo Mzantsi Afrika yindawo enetha imvula ehlotyeni, ngenyanga ka November ukuya kweka March, logama iphondo lase Ntshona Koloni lifumana inkoliso yemvula ngexesha lase busika, ngenyaka ka May ukuya kwinyanga ka August.
Ngaphezulu koninzi lo Mzantsi Afrika, ikhona indlela ethile yokunetha kwemvula, nemvula ethi yande ukusuka ngase ntshona ukuya ngase mpuma. Oku kubonakaliswa ngumahluko wemvula minyaka le phakathi kwe Port Nolloth ngakunxweme olusentshona, ama 50 mm, ze eRichards Bay ibengama 1 000 mm wemvula, ngoku linganayo kunxweme olungase mpuma yolwandle.
Umhlaba ongaphakathi, kwimpuma ye Free State, KwaZulu-Natal, kwiphondo lase Mpuma Koloni kunye nelase Mpumalanga zifumana phantse yonke imvula izanjenge ndudumo, imvula ekwaziyo ukutshintsha inethe ngamandla. Ezimvula zingamandla zenzeka kuba ezindawo zinobushushu obaneleyo ehlotyeni. Ngamafutshane, umoya oshushu ofumileyo uye wonyuke, uphinde uphole, udibane ze uhle njenge ndudumo.
Kwimimandla esentshona kweli lo Mzantsi Afrika, amazinga emvula asezantsi kuba akukho ukufuma okwaneleyo emoyeni obenziwa zimvula ezimandla. Kwakhona alikho ifuthe elaneleyo lemvula eyenzeka phezulu kwentaba (orographic) ezikwi mimandla yentshona enentaba. Oku kwenziwa kukuba umoya obandayo osuka elwandle awubambi ukufuma okuninzi kwaye imimoya yangase lwandle ivuthuza ngoku linganayo ezintabeni. Imvula ezenzeka phezulu kwentaba zenzeka xa umoya ofumileyo unyanzeleka okokuba wokunyuke phezulu kwentaba.

Indawo ezine Mvula eninzi eMzantsi Afrika

©Eric Miller
Imvula eninzi eMzantsi Afrika yenzeka kwi mpuma nakuma zantsti wentaba ezifana ne Drakensberg, ukusuka eLimpopo ukuya eMpumalanga kunye na KwaZulu-Natal ukuya kumantla we Ntshona Koloni. Ezinye intaba ezinemvula ephezulu ziquka intaba i-Outenqua, iintaba eziku Mzantsi-we Ntshona Koloni kunye ne Winterberg nentaba i-Amatola, kwindawo ezikum-mandla we Mpuma Koloni. Imvula eninzi ezintabeni yenziwa zimvula eziqala khona phezulu kwentaba (orographic).
Indawo zemvula eziqala ezintabeni zibaluleke kakhulu ekunkcenkcesheleni kwifama ezikwindawo ezomileyo maxa wambi amakhulu we kilometres ubude. Imvula esuka kwintaba yase Drakensberg / Maluti yase Lesotho kunye nase Mpuma Koloni zityiswa nge tonele ukuze kunkcenkceshelwe indawo ezisesiphakathini eMzantsi wendawo ezikwi Orange Rivers.
Umzekelo omhle we orographic rain ubonakala kwelase Mpuma Koloni kwindawo engqonge i-Alice. Imvula eqhelekileyo ngonyaka e-Alice kwinyawo zentaba ye Amatola ngama 500 mm, kodwa kwintaba iWolfridge, imvula enetha ngonyaka ngama 1 700 mm. eyona mvula ininzi ifumaneka eWemmershoek, intaba ezingaphezulu kwe Franshoek, apho imvula eqhelekileyo ngonyaka ingapha kwama 3 000 mm.

Inkanyamba kunye Nenqele Enamandla esuka ngase Lwandle

Imvula ephezulu KwaZulu-Natal kunye nemimandla esemntla-mpuma we Mpuma Koloni yenziwa ngumoya omninzi ofumileyo esuka kubushushu base Mozambique. Maxa wambi kubakho inkanyamba okanye isichotho, esizisa iimvula ezimandla ezihamba nezikhukhula.
Iimvula zase busika zase mzantsi-ntshona kunye namazantsi we kapa iziswa yinkanyamba okanye ingqele ezisuka ngase lwandle ezimandla. Iingqele ezisuka ngase lwandle zichwechwela elase Ntshona Koloni kwicala lase ntshona, zidlule iphondo ukuya ngase mpuma. Ezintsuku zinengqele zizisa imini zemvula epholileyo, kodwa imvula eqhelekileyo ngonyaka kwezi ndawo isezantsi. Isizathu esikhulu semvula esezantsi sesokuba lomoya ufumileyo usuka kulwandle olubandayo, oku kuthi kwenze amazinga aphantsi womphunga.

Iindlela Ezikhethekileyo Zemvula

©Jacques Marais
Iintili ezinzulu
Imvula ebalulekileyo, ekhethekileyo ethi ifumaneke ngokwendawo ezithile, ifumaneka kwintili zemilambo enzulu yase Mpuma Koloni kunye na KwaZulu-Natal. Ezintili zinobushushu zinemvula esezantsi kunendawo ezilinganayo eziphakathi kwazo. Ngenxa yobushushu obuphezulu entilini, kukho izinga eliphezulu lokuchiphiza, izityalo ziphulukana namanzi, umphunga, zonke ezi zifuna izilimo ezinkcenkcesheliweyo.
Kwi Sunday River Valley, imvula efumanekayo ngonyaka e-Addo ngama 390 mm kuphela, kwaye obona bushushu buphezulu eMzantsi Afrika bashicilelwa eKirkwood, bungama 55℃. Kwakhona, phakathi eKeiskamma River Village imvula eqhelekileyo eDank den Goewerneury ngama 390 mm kuphela, kodwa eMiddledrift ngama 500 mm, ekufutshane kodwa engaphandle kwentili enzulu.
Imbalela Phakathi Ehlotyeni
Indawo ezinetha imvula ehlotyeni zohlulwe ngokwendawo eziyifumana kwangethuba imvula, esiphakathini, emveni kwexesha okanye imvula enetha xa ihlobo lisiya ekupheleni. Oku kubonakalisa inyanga apho imvula yasehlotyeni ithi yande, hayi ukuba imvula yehlobo iqala nini.
Umphakathi we Ntshona Koloni ubonakalise uhlobo olukhethekileyo lwemvula yehlobo; intwana encinci yentwasa-hlobo kunye neninzi ekupheleni kwehlobo/ ekuqaleni kokwindla. Esiphakathini kukho imbalela eyenzeka phakathi ehlotyeni. Imvula isezantsi kwaye namazinga obushushu aphezulu enza umvandedwa wamanzi kwisivuno sase hlotyeni esisakhulayo.
Amafama kufuneka abenecebo lemini zika xakeka kunye neendlela zokunciphisa ilahleko nomonakalo kwisivuno ngamaxesha apho amanzi anqongophele khona.
Izifafazi ezenza izityalo zingabili (Anti-transpirant) zinganciphisa ilahleko yamanzi ngukubila. Kungenzeka zibe kumaxabiso aphezulu ezi kwaye zibenemiphumela emibi, efana nokwehlisa ilanga elithi likhuse izityalo (photosynthesis). Kwimeko ezimaxongo, imithi ingasikwa ukwehlisa indawo yamagqabi inciphise ukubila. Oku kwenziwa kwi gadi yeziqhamo ze citrus eLetsitele ngexesha lembalela yeminyaka yama 1980.

Translated by Zikhona Plaatjie