Usoro nke Ihe Omume La Niña
La Niña bụ otu n'ime ihe ndị na-eme n'ụwa niile nke nwere mmetụta kachasị na ụdị ihu igwe n'akụkụ dị iche iche nke ụwa, gụnyere Indonesia. Ihe a bụ akụkụ nke usoro okike a maara dị ka ENSO (El Niño-Southern Oscillation), ya bụ mmekọrịta dị mgbagwoju anya dị n'etiti ikuku na oke osimiri dị n'Oké Osimiri Pasifik nke okpomọkụ. Ọ bụ ezie na El Niño na-adakọ na okpomọkụ elu oké osimiri na etiti ọwụwa anyanwụ Pacific, La Niña bụ ihe dị iche, ya bụ ọnọdụ mgbe okpomọkụ elu oké osimiri dị na mpaghara ahụ na-ajụ oyi karịa ka ọ dị. Mgbanwe okpomọkụ a anaghị eguzo naanị ya, kama ọ na-akpali usoro mmeghachi omume yinye na ifufe, nrụgide ikuku, nhazi igwe ojii, na mmiri ozuzo . Ịghọta usoro nke La Niña dị mkpa ka obodo na gọọmentị nwee ike ịtụ anya mmetụta ya, dị ka mmụba mmiri ozuzo , idei mmiri, na mmebi na ngalaba ọrụ ugbo na azụ.
1. La Niña dịka akụkụ nke Sistemụ ENSO
ENSO bụ usoro mgbanwe oge (mgbanwe), nke na-emekarị kwa afọ 2-7. N'okpuru ọnọdụ na-anọpụ iche (nkịtị), Oké Osimiri Pasifik nke ebe okpomọkụ nwere usoro mgbasa ozi kwụsiri ike: ọdịda anyanwụ Pacific (dị nso Indonesia na Australia) na-adịkarị ọkụ, ebe ọwụwa anyanwụ Pacific (dị nso South America) na-ajụ oyi n'ihi mmụba mmiri (mmụba nke mmiri oyi site n'okpuru oké osimiri). Mgbe usoro a na-enwe nnukwu mgbanwe, usoro El Niño ma ọ bụ La Niña na-eme.
A maara La Niña site na:
– Ịjụ oyi nke ihe ndị na-adịghị mma gbasara okpomọkụ elu oké osimiri (SST) na etiti na ọwụwa anyanwụ nke Equatorial Pacific.
– Ime ka ifufe azụmaahịa si n'ọwụwa anyanwụ ruo n'ọdịda anyanwụ sie ike.
– Mgbanwe na ụkpụrụ nrụgide ikuku nke na-emetụta mgbasa ikuku, ọkachasị Walker Circulation.
– Mmegharị nke ebe a na-akpọ convection center (mmepụta nke igwe ojii mmiri ozuzo) gaa na mpaghara ọdịda anyanwụ Pacific.
2. Ọrụ nke Okpomọkụ Elu Oké Osimiri: Mmalite nke Agbụ Mgbanwe
Usoro La Niña na-amalitekarị site na mgbanwe na okpomọkụ elu oké osimiri na Pacific nke ebe okpomọkụ. Mkpọnwụ a na-emekarị na mpaghara a maara dị ka Niño 3.4 (gburugburu etiti Pacific), nke a na-ejikarị eme ihe dị ka ihe ngosi mbụ. Mgbe okpomọkụ dị na mpaghara a dara ihe dị ka 0,5°C ma ọ bụ karịa n'okpuru nkịtị ruo ọtụtụ ọnwa n'usoro, ọnọdụ na-amalite ịgbanwe gaa na La Niña.
Oyi a dị oke mkpa n'ihi na oke osimiri bụ "onye na-enye ike" maka ikuku. Mmiri oké osimiri oyi na-ebelata uzuoku, na-ebelata oke uzuoku mmiri na-ebilite n'ikuku na etiti ọwụwa anyanwụ Pacific. N'ihi ya, ígwé ojii na mmiri ozuzo na mpaghara a na-adịghị ike, ebe ọdịda anyanwụ Pacific na-arụsi ọrụ ike karị n'ịmepụta ígwé ojii convective n'ihi na okpomọkụ oké osimiri na-anọgide na-ekpo ọkụ ma ọ bụ ọbụna na-ekpo ọkụ karịa nkezi.
3. Ime Ka Ifufe Azụmahịa Sikwuo Ike na Mmetụta "Ịkwapụ" nke Mmiri Oké Osimiri
Otu n'ime ihe ndị dị mkpa na La Niña bụ ifufe azụmaahịa nke ọwụwa anyanwụ nke na-efe site n'ụsọ oké osimiri South America gaa na Ndịda Ọwụwa Anyanwụ Eshia. N'oge ọnọdụ La Niña, ifufe azụmaahịa ndị a na-esiwanye ike. Ike ifufe azụmaahịa nwere nnukwu mmetụta abụọ:
1. Ịkwaga mmiri ọkụ gaa n'ọdịda anyanwụ
Mmiri dị n'elu ala Mmiri ọkụ na-agbakọta ma na-agbakọta na ọdịda anyanwụ Pacific (gburugburu Indonesia, Papua New Guinea, na ugwu Australia). Mkpokọta a na-eme ka ọdịiche dị n'ọkwa oke osimiri dịkwuo elu: ọ dị elu karịa n'ọdịda anyanwụ, ọ dị ala karịa n'ọwụwa anyanwụ.
2. Ime ka mmụba elu dị n'ọwụwa anyanwụ sikwuo ike
Oge Awa a na-akwapụ mmiri ọkụ n'elu ala n'ụsọ oké osimiri South America, a na-eji mmiri oyi, nke bara ụba na ihe oriri sitere na oyi akwa dị ala dochie oghere tọgbọ chakoo n'elu. A na-akpọ usoro a upwelling, ọ bụkwa isi ihe mere ọwụwa anyanwụ Pacific ji ajụ oyi n'oge La Niña.
Ebe ọ bụ na ifufe azụmaahịa na mmụgharị elu na-eme ka ibe ha sie ike, oyi dị n'ọwụwa anyanwụ nwere ike ịdịgide ruo ogologo oge ma ọbụna gbasaa ruo etiti Pacific.
4. Ịgbagharị n'Ọgbakọ: Igwe Ikuku nke Na-agbanwe Ụkpụrụ
La Niña nwere njikọ chiri anya na mgbanwe na Walker Circulation, mgbasa ikuku nke ọwụwa anyanwụ ruo ọdịda anyanwụ n'akụkụ equatorial Pacific. N'ikwu ya n'ụzọ dị mfe, Walker Circulation na-arụ ọrụ dịka nke a:
– Ikuku na-ekpo ọkụ ma dị mmiri mmiri na-arị elu (convection) n'ebe ndị nwere oke osimiri na-ekpo ọkụ → na-emepụta ígwé ojii na mmiri ozuzo.
– N’ikuku dị n’elu, ikuku na-aga n’ebe ọwụwa anyanwụ.
– Ikuku na-agbada n'elu ebe oyi na-atụ ma kpọọ nkụ.
– N’elu elu, ikuku na-alaghachi n’ọdịda anyanwụ dịka ifufe azụmaahịa.
Mgbe La Niña mere, oke osimiri dị na ọdịda anyanwụ Pasifik na-ekpokwu ọkụ, ebe ọwụwa anyanwụ Pasifik na-ajụ oyi. N'ihi ya:
– Mmụba nke mmiri ozuzo na mmụba na ọdịda anyanwụ Pasifik (gụnyere Indonesia).
– Ikuku na-agbada nke ọma n'etiti ọwụwa anyanwụ Pacific, na-eme ka mpaghara ahụ kpọọ nkụ.
– Ifufe azụmaahịa na-eme ka ọ sie ike, nke na-eme ka oyi na mmụba dịkwuo elu.
Nke a bụ ihe atụ nke usoro nzaghachi dị mma a ma ama na ENSO, nke a na-akpọkarị nzaghachi Bjerknes: oyi oyi → ike nke ifufe azụmaahịa → mmụba elu → ọbụna oyi siri ike.
5. Ọrụ nke Thermocline: "Oke" nke Na-ekpebi Ịkwụsi Ike nke La Niña
N'okpuru elu oké osimiri ahụ, e nwere ihe mkpuchi mgbanwe okpomọkụ a na-akpọ thermocline, nke kewara mmiri ọkụ dị n'elu na mmiri oyi dị n'okpuru. Omimi nke thermocline na-emetụta nke ukwuu otú mmiri oyi si ebili n'elu si eme ka ọ dị mfe ma ọ bụ sie ike.
N'oge La Niña:
– Thermocline dị n'ebe ọwụwa anyanwụ Pacific na-adịkarị obere, nke na-eme ka mmiri oyi na-arịgo n'elu ya ngwa ngwa.
– Thermocline dị na ọdịda anyanwụ Pacific na-adịkarị omimi, nke na-egosi na mmiri ọkụ agbakọtala.
Ihe dị iche na mkpọda thermocline (ịtụgharị site na ọdịda anyanwụ miri emi ruo na ọwụwa anyanwụ miri emi) bụ ihe e ji mara ọnọdụ La Niña siri ike, ọ na-emekwa ka ihe a kwụsie ike ka ọ dịgide ruo ọtụtụ oge.
6. Ebili Mmiri Oké Osimiri na Ihe Ndị Na-akpali Mmalite (Kelvin na Rossby)
Na mgbakwunye na ifufe na thermoclines, usoro La Niña na-agụnyekwa nnukwu ebili mmiri oké osimiri, ọkachasị:
- Ebili mmiri Kelvin (na-aga n'ebe ọwụwa anyanwụ n'akụkụ equator)
- Ebili mmiri Rossby (na-aga ọdịda anyanwụ)
Mgbanwe na ifufe equatorial nwere ike ịkpalite ebili mmiri ndị a, nke na-agbanwe omimi thermocline na nkesa okpomọkụ dị n'okpuru ala. Mgbe ebili mmiri na-eduga n'iju oyi karịa, ohere nke La Niña na-abawanye. N'ikwu ya n'ụzọ ọzọ, La Niña abụghị naanị "okwu elu," kamakwa ọ gụnyere nchekwa okpomọkụ na mbufe n'ime oyi akwa miri emi.
7. Mmetụta na Mmiri ozuzo: Gịnị mere Indonesia ji adịkarị mmiri mmiri karịa?
Ka ebe a na-ebugharị ihe na-agagharị ma na-esiwanye ike na ọdịda anyanwụ Pasifik, Indonesia na-enwekarị ahụmịhe:
– Mmiri ozuzo karịrị nke nkịtị, ọkachasị n'ebe ụfọdụ ifufe udu mmiri na ọnọdụ mpaghara nke oke osimiri gbara ya gburugburu metụtara.
– Oke mmiri ozuzo na-eme ugboro ugboro, nke nwere ike ibute idei mmiri na mbuze.
– Mgbanwe oge, dịka ọmụmaatụ oge mmiri ozuzo dị ogologo ma ọ bụ oge kachasị elu dị oke njọ.
Agbanyeghị, mmetụta La Niña na Indonesia anaghị adị otu mgbe niile. Ọnọdụ mpaghara ndị ọzọ dịka Oke Osimiri India (IOD ), okpomọkụ oké osimiri na mmiri Indonesia, na ike nke monsoon Eshia na Australia nwere ike ime ka mmetụta La Niña sikwuo ike ma ọ bụ belata.
8. Ọgwụgwụ nke okirikiri La Niña
La Niña anaghị adịte aka. Ọ na-ebelatakarị mgbe:
– Ifufe azụmaahịa amalitela ịlaghachi n'ọnọdụ nkịtị ma ọ bụ ịda mbà.
– Mmụba n'ọwụwa anyanwụ na-ebelata.
– Okpomọkụ dị n'elu oké osimiri na etiti ọwụwa anyanwụ Pacific na-alaghachi n'ihe fọrọ nke nta ka ọ bụrụ nkezi.
Mgbe ụfọdụ, La Niña nwere ike ịdịru ihe karịrị otu afọ (La Niña nke ga-ewe ọtụtụ afọ) ma ọ bụrụ na nzaghachi nke oké osimiri na ikuku anọgide na-adị ike ma ebe nchekwa okpomọkụ dị n'okpuru ala ezughị iji mee ka etiti-ọwụwa anyanwụ Pacific dịghachi ọkụ.
Mmechi
Usoro nke La Niña bụ n'ihi mmekọrịta chiri anya dị n'etiti oke osimiri na ikuku dị n'Oké Osimiri Pasifik nke dị n'ebe okpomọkụ. Ime ka okpomọkụ dị n'elu oké osimiri dị jụụ na etiti ọwụwa anyanwụ Pacific na-akpalite ike nke ifufe azụmaahịa, na-eme ka mmụba dịkwuo elu, na-agbanwe mkpọda thermocline, ma na-eme ka Walker Circulation sikwuo ike. Usoro a na-emepụta usoro nzaghachi dị mma nke na-enye La Niña ohere ịnọgide ruo ọnwa ruo ihe karịrị otu afọ. Mmetụta ahụ gbasaara ebe niile: ọdịda anyanwụ Pacific, dị ka Indonesia, na-adịkarị mmiri mmiri karịa, ebe ọwụwa anyanwụ Pacific na akụkụ nke America na-adịkarị ka akpọnwụ. Site na nghọta ka mma nke usoro La Niña, enwere ike ịhazi mgbalị mbelata na mgbanwe nke ọma, karịsịa iji belata ihe egwu nke ọdachi hydrometeorological ma nọgide na-enwe nchekwa nri.
Ọ bụrụ na ịchọrọ, enwere m ike ịgbanwe akụkọ a ka ọ bụrụ nke sayensị karịa (na ntụaka akwụkwọ akụkọ), ma ọ bụ nke a ma ama maka ndị na-agụ akwụkwọ n'ụlọ akwụkwọ, yana itinye data gbasara mmetụta La Niña kpọmkwem maka Indonesia.
