Yini U-El Niño?

Ngesikhathi uMfula i-Apurímac ohlala ushile, oseduze kweLima, ePeru, ukhukhula cishe yonke into uCarmen ayenayo, wakhala: “Sibaningi esivelelwe yilokhu, sibaningi kakhulu. Akumina ngedwa.” Enyakatho ekude, izikhukhula zashintsha ingxenye engasemngceleni woGwadule LwaseSechura yaba yichibi elingelesibili ngobukhulu ePeru, elemboza indawo engamakhilomitha-skwele angu-5 000. Kwezinye izindawo emhlabeni, izikhukhula eziyingqopha-mlando, izishingishane nesomiso esikhulu kwabangela indlala, izifo, umlilo wequbula futhi kwacekela phansi izitshalo, impahla nendawo. Kwakubangwa yini konke lokhu? Abaningi bakhomba u-El Niño, owaqubuka ePacific Ocean eshisayo noma engasenkabazwe ngasekupheleni kuka-1997 futhi wathatha izinyanga ezingaba ngu-8.

Uyini ngempela u-El Niño? Uqala kanjani? Kungani umonakalo awubangelayo usakazeke kangaka? Ingabe kungabikezelwa ngokunembile ukuthi uzophinde abe khona nini, mhlawumbe kuncishiswe umonakalo awubangelayo ezintweni eziphilayo nasempahleni?

Uqala Ngokushisa Kwamanzi

Umagazini i-Newsweek uthi: “Uma sisho ngokuthe ngqó, u-El Niño umane ungumsinga wamanzi ashisayo avela olwandle ePeru njalo emva kweminyaka emibili kuya kweyisikhombisa.” Sekungaphezu kweminyaka eyikhulu, amatilosi ahamba ogwini lwasePeru ephawula ukushisa okunjalo. Njengoba le misinga eshisayo ivame ukuba khona ngoKhisimusi, yaqanjwa ngokuthi u-El Niño, igama leSpanishi elisho uJesu owusana.

Ukushisa kwamanzi ngasogwini lwasePeru kuletha imvula eningi kulelo zwe. Izimvula zibangela ukuba izingwadule zihlume nemfuyo ichume. Uma izimvula zizinkulu, ziletha nezikhukhula kule ndawo. Ngaphezu kwalokho, ingxenye eshisayo engaphezulu yamanzi asolwandle ivimbela amanzi angaphansi abandayo anezakhi ekubeni angayi phezulu. Ngenxa yalokho, izilwane eziningi zasolwandle ngisho nezinyoni ziyafuduka ziyofuna ukudla. Ngemva kwalokho imiphumela ka-El Niño ifinyelela kwezinye izindawo ezikude nogu lwasePeru.a

Ubangwa Umoya Namanzi

Yini ebangela ukukhuphuka kwezinga lokushisa okungavamile olwandle ngasogwini lwasePeru? Ukuze uqonde lokhu, qala ucabangele umjikelezo womoya omkhulu owaziwa ngokuthi iWalker Circulation, osemkhathini phakathi kwePacific eshisayo esempumalanga nesentshonalanga.b Njengoba ilanga lishisa ingxenye ephezulu yamanzi entshonalanga, eduze ne-Indonesia ne-Australia, umoya oshisayo nonomswakama uyaphakama uye emkhathini, ubangele isimiso somfutho womoya esiphansi phezu kwamanzi. Umoya okhuphukayo uyaphola bese udedela umswakama wawo, wenze kune imvula kuleyo ndawo. Umoya ongenawo umswakama uthuthwa umoya ophezulu emkhathini uwuyise empumalanga. Njengoba uya empumalanga, lo moya uyaphola futhi usinde bese uqala ukushona phansi lapho ufika ePeru nase-Ecuador. Lokhu kubangela isimiso somfutho womoya esiphakeme eduze kolwandle. Futhi, ezindaweni eziphansi, imimoya eyaziwa ngokuthi ama-trade wind iphindela emuva entshonalanga ngase-Indonesia, ngaleyo ndlela iqede umjikelezo.

Le mimoya ilithinta kanjani izinga lokushisa phezu kwePacific eshisayo? I-Newsweek ithi: “Le mimoya ivame ukwenza njengemimoya ehelezayo esesizibeni esincane, isunduze amanzi ashisayo iwayise ePacific esentshonalanga ukuze ulwandle luphakame ngamafidi amabili [amasentimitha angu-60] futhi lushise ngo-15° Fahrenheit [8° Celsius] kuphela kunakwezinye izindawo, ngokwesibonelo e-Ecuador.” EPacific esempumalanga, amanzi abandayo angaphansi agcwele izakhi akhuphukela phezulu, abangele ukuba izilwane zasolwandle zichume. Ngakho-ke, ngeminyaka evamile, noma esuke ingenaye u-El Niño, kuyabanda empumalanga kunasentshonalanga.

Yiluphi ushintsho emkhathini olubangela u-El Niño? I-National Geographic ithi: “Ngezizathu ososayensi abangakaziqondi namanje, njalo eminyakeni emibalwa ama-trade wind ayabohla noma aphele.” Njengoba le mimoya incipha, amanzi ashisayo anqwabelene eduze kwe-Indonesia aphindela emuva empumalanga, akhuphule izinga lokushisa laphezu kolwandle lwasePeru nakwezinye izindawo ezisempumalanga. Lokhu kuba nethonya kamuva esimisweni sasemkhathini. “Ukushisa kwePacific Ocean esempumalanga kuqeda iWalker Circulation amandla futhi kubangele indawo yokuhlangana yemvula enkulu iye ngasempumalanga, isuke entshonalanga iye ePacific ephakathi nesempumalanga,” kusho enye incwadi. Ngakho-ke, isimo sezulu siyathinteka kuyo yonke iPacific esenkabazwe.

Njengembokodo Esemfudlaneni

U-El Niño angase ashintshe nesimo sezulu ezindaweni ezikude nomsinga wamanzi ePacific eshisayo. Kanjani? Ngokusebenzisa isimiso esijikelezayo sasemkhathini. Imiphumela ephawulekayo yokuphazamiseka komjikelezo emkhathini wasendaweni ingafaniswa nendlela imbokodo eyodwa ephakathi nomfudlana engabangela ngayo ukuba amanzi abe namagagasi amancane emfudlaneni wonke. Amafu amnyama emvula avela ngaphezu kwamanzi olwandle olushisayo enza isithiyo esinjengembokodo emkhathini, esithinta isimo sezulu endaweni eqhele ngamakhilomitha amaningi.

Ezindaweni eziphakeme, u-El Niño uyaqina futhi athathe indawo yemimoya esheshayo eya empumalanga eyaziwa ngokuthi ama-jet stream. Ama-jet stream aqondisa ukuhamba kwezivunguvungu eziningi kulezi zindawo. Ukuqina nokushintsha kwama-jet stream nakho kungase kusenze sibe sibi kakhulu noma kusilawule isimo sezulu ngezinkathi ezithile. Ngokwesibonelo, ubusika buka-El Niño abubandi kakhulu njengobuvamile ezingxenyeni ezisenyakatho ye-United States, kuyilapho buvame ukuba nezimvula futhi bubande kwezinye izindawo eziseningizimu.

Angakwazi Ukubikezelwa?

Imiphumela yesiphepho ngasinye ingase ibikezelwe sekusele izinsukwana sifike. Ingabe kungokufanayo nangokuzama ukubikezela u-El Niño? Cha. Kunokuba kuhilele izenzakalo zesimo sezulu zesikhashana, ukubikezela u-El Niño kuhilela isimo sezulu esingavamile ezindaweni ezinkulu esithatha izinyanga ngesikhathi. Futhi abacwaningi besimo sezulu baye baphumelela ngesilinganiso esithile ukubikezela u-El Niño.

Ngokwesibonelo, isibikezelo sika-El Niño ngo-1997-98 sakhishwa ngo-May 1997—kusasele izinyanga eziyisithupha ngaphambi kokuba enzeke. Manje ePacific eshisayo kusakazwe izinto ezintantayo ezingu-70 zokukala izimo zomoya phezu kolwandle kanye namazinga okushisa ukuya phansi ekujuleni kuze kufike emamitheni angu-500. Uma kufakwa kuyi-computer enesimiso sesimo sezulu, lokhu kwaziswa kunikeza izibikezelo zezulu.

Ukuxwayiswa kusengaphambili ngo-El Niño ngempela kungasiza abantu bazilungiselele ushintsho olulindelekile. Ngokwesibonelo, kusukela ngo-1983, izibikezelo zika-El Niño ePeru ziye zakhuthaza abalimi abaningi ukuba bafuye izinkomo futhi batshale izitshalo ezizwana nemvula, kuyilapho abadobi beye bayeka ukudoba izinhlanzi kodwa badoba izimfanzi eziza namanzi ashisayo. Yebo, ukubikezela okunembile kanye nokulungiselela kusengaphambili kunganciphisa usizi olubangelwa u-El Niño kubantu nakwezomnotho.

Ukucwaninga kwezesayensi ngenqubo elawula isimo sezulu somhlaba wethu kufakazela ukunemba kwamazwi aphefumulelwe alotshwa yiNkosi uSolomoni yakwa-Israyeli wasendulo eminyakeni engaba ngu-3 000 edlule. Wabhala: “Umoya uya ngaseningizimu, uzungeze, uye ngasenyakatho; uzungazungeza njalo ekuhambeni kwawo, nasekuzungezeni kwawo umoya uyabuyela.” (UmShumayeli 1:6) Umuntu namuhla uye wafunda okuningi ngesimo sezulu ngokucwaninga umoya nomoya wasolwandle. Kwangathi singazuza kulolo lwazi ngokulalela izixwayiso ezimayelana nezenzakalo ezinjengo-El Niño.

[Imibhalo yaphansi]

[Ibhokisi ekhasini 27]

UMKHONDO WOMONAKALO KA-EL NIÑO

■ Ngo-1525: Umlando ogciniwe omdala kunayo yonke wesenzakalo sika-El Niño ePeru.

■ Ngo-1789-93: U-El Niño wabulala abantu abangaphezu kuka-600 000 eNdiya futhi wabangela indlala enkulu e-Afrika eseningizimu.

■ Ngo-1982-83: Lesi senzakalo sabulala abantu abangaphezu kuka-2 000 nokulimala kwempahla engaphezu kwezigidi eziyizinkulungwane ezingu-80, ikakhulu ezindaweni ezishisayo.

■ Ngo-1990-95: Izenzakalo ezintathu ezilandelanayo zahlangana zenza esinye sezenzakalo zika-El Niño ezathatha isikhathi eside kunazo zonke emlandweni.

■ Ngo-1997-98: Naphezu kokuba kwakuyisibikezelo sokuqala esaphumelela kakhulu endaweni enkulu sezikhukhula nesomiso sika-El Niño, kwafa abantu abangaba ngu-2 100, futhi kwadaleka umonakalo ofinyelela ezigidini zamaRandi eziyizinkulungwane ezingu-202 emhlabeni wonke.

[Imidwebo/Amabalazwe ekhasini 24, 25]

(Ukuze ubone ukuthi indaba ihlelwe kanjani, bheka encwadini)

AVAMILE

Umzila weWalker Circulation

Ama-“trade wind” anamandla

Amanzi ashisayo asolwandle

Amanzi abandayo asolwandle

U-El NIÑO

Ama-“jet stream” achezuka ezindleleni

Ama-“trade wind” angenamandla

Amanzi ashisayo aya ngasempumalanga

Oshisayo noma owomile kunovamile

Obandayo noma oswakeme kunovamile

[Imidwebo/Izithombe ekhasini 26]

(Ukuze ubone ukuthi indaba ihlelwe kanjani, bheka encwadini)

U-El NIÑO

Imibala ebomvu eseshadini elingenhla imelela amanzi ashisa kakhulu kunavamile

AVAMILE

Amanzi ashisayo anqwabelana entshonalanga yePacific, evumela amanzi abandayo anezakhi ukuba akhuphuke empumalanga

U-El NIÑO

Ama-“trade wind” angenamandla avumela amanzi ashisayo ukuba abuyele empumalanga, evimbela amanzi abandayo ukuba angakhuphuki

[Izithombe ekhasini 24, 25]

EPERU

UGwadule LwaseSechura olugcwele izikhukhula

EMEXICO

ISiphepho uLinda

ECALIFORNIA

Ukugeleza kodaka

[Imithombo]

Pages 24-5 left to right: Fotografía por Beatrice Velarde; Image produced by Laboratory for Atmospheres, NASA Goddard Space Flight Center; FEMA photo by Dave Gatley