He aha i roa ake ai te wā ua i ngā rohe o te Equatorial
E mōhiotia ana ngā rohe o te Ekueta—ngā rohe e karapoti ana i te Ekueta—mō ō rātou ua nui me ngā wā ua roa ake i ngā rohe hauāuru, waenga-rohe rānei. Hei tauira, ko Initonīhia, hei whenua moutere e whiti ana i te Ekueta, ka pāngia e ngā tauira ua e "auau ake" me te "roa ake" i ngā wāhi maha i ngā wā e whā e kitea ana i ngā rohe mahana. Ehara tēnei āhuatanga i te mea tūpono noa, engari he hua o te huinga o ngā āhuatanga o te hau, te tauwāhi whenua, ngā kaha o te hau o te wā, me te awe o ngā moana whānui. Nō reira, he aha i roa ake ai ngā wā ua i ngā rohe o te Ekueta? Anei te whakamārama.
1. He pumau te kaha o te whakamahana o te rā puta noa i te tau.
Ko te mea nui ki te āhuarangi o te ekueta ko te rite tonu o te hihi o te rā. I te taha o te ekueta, he tika ake te koki o te pānga o te rā puta noa i te tau i ērā o ngā wāhi e tawhiti atu ana i te ekueta. Nā reira, ka whiwhi te mata o te Ao—te whenua me te moana—i te nui o te pūngao wera e ōrite ana i ia marama ki ia marama.
Nā te mahana tonu o te rangi ka nui haere te mimiti, ka roa hoki te mimiti. Ka nui ake te mimiti, ka nui ake te kohu wai e kohia ana ki te āhuarangi. Ko tēnei kohu wai te "rauemi mata" mō te hanganga o ngā kapua ua. Nā te mea kāore i tino heke te nui o te kohu wai i roto i tētahi wā, ka nui ake te kaha o te ua, ā, ka roa ake te wā ua.
2. Te Tūranga o te Rohe Whakakotahitanga o te Ao Whānui (ITCZ)
Ko tētahi o ngā tikanga tino nui e pupuri ana i te makuku o te rohe ekueta ko te Rohe Whakakotahitanga o ngā Ao Whānui (ITCZ). Ko te ITCZ he whitiki e tūtaki ai ngā hau hokohoko mai i te Ao Raki me te Ao Tonga. Ina tūtaki ēnei papatipu hau e rua, ka akiakihia te hau kia piki ake (te whakakotahitanga me te hiki). Ka whakamatao tēnei hau e piki ake ana, ka whakapūpū te mamaoa wai, ka hanga he kapua cumulonimbus, ā, i te mutunga ka puta he ua nui.
Kāore te ITCZ e noho tonu i te wāhi kotahi. Ka neke tōna tūranga i runga i te nekehanga ā-tau o te rā: ka neke whaka-te-raki ina mahana ake te tuakoi raki, kātahi ka hoki whaka-te-tonga ina mahana ake te tuakoi tonga. Nā te mea kei roto te rohe ekueta i te "ara" o te ITCZ, he maha ngā rohe huri noa i te ekueta ka pāngia e te ITCZ kotahi, e rua rānei i te tau. Nō reira, ka roa ake te wā ua—ko ētahi wāhi ka pāngia e ngā wā ua nui e rua (he tauira rua-ara).
3. Te tohanga o Hadley: ka piki te hau i te ekueta, ka heke ki raro i te rohe pārūrū
I te ao whānui, he nui ngā tauira tohanga o te hau i roto i te āhuarangi, ko tētahi o ēnei ko te pūtau Hadley. Ko te tikanga māmā ko te wera o te hau i te ekueta, ka māmā ake, kātahi ka piki ake. Ina tae atu ki ngā paparanga teitei o te āhuarangi, ka neke te hau ki ngā rohe hau-hauāuru, kātahi ka heke anō i te whānui o te 20–30° (he maha ngā rohe koraha e hanga ana i tēnei rohe heke), ā, ka rere anō ki te ekueta hei hau hokohoko.
Nā te mea ko te rohe ekueta te rohe e piki ake ana te hau i roto i tēnei pūnaha, he nui ake te kitea o te hanganga kapua me te ua. I taua wā, i ngā rohe hau-hauāuru, he maroke ake te hau e heke iho ana, ā, he aukati i te hanganga kapua. Koinei te take e kitea ai te maha o ngā koraha i ngā rohe hau-hauāuru, ko te rohe ekueta ia he ingoa mō ngā ngahere ua-hauāuru me te nui o te ua.
4. Te haumākū nui me te "mīhini kawe hiko" o ia rā
I roto i te nuinga o ngā rohe o te ekueta, inā koa ko ērā e tata ana ki te moana, he nui te haumākū i te nuinga o te tau. Nā te whakakotahitanga o te wera me te makuku ka kore e pumau te āhuarangi—arā, ka tere te whakaoho i te convection: ka tere te piki o te hau mahana, makuku i te mata hei hanga kapua teitei.
He maha ngā wā ka puta tēnei whakawhiti hau i ia rā, i ia rā. I ētahi rohe pārūrū, ko te āhua noa ko ngā ata paki, ngā ahiahi mahana, ā, ka ua me ngā whatitiri i te ahiahi. Ahakoa ehara i te mea ka puta i ia rā, ka roa ake te wā ua nā tēnei āhuatanga "ua ngāwari", nā te mea ka taea te ua ahakoa i waho o te tihi o te wā ua.
5. Te awe o te moana nui: kāore e mutu te tuku mai o te mamaoa wai
He maha ngā rohe o te ekueta (tae atu ki a Initonīhia, Mareia, Papua Niu Kini, me ngā moutere o te Moana-nui-a-Kiwa) e karapotia ana e ngā wai mahana. He puna nui te moana mō te mamaoa wai. Ki te whakaritea ki te whenua, ka puhoi ake te wera me te whakamatao o te moana, ā, ka noho pumau tonu te pāmahana o te mata o te moana.
Ka whakanui ake te pāmahana mahana o te moana i te mimiti, ka whakanui ake i te nui o te kohu wai o te āhuarangi, ā, ka tautoko i te hanganga o ngā kapua ua. Ina pupuhi mai ngā hau mai i te moana ki uta, ka haria tēnei kohu wai ki roto, ā, ka taka hei ua, inā koa ka akiakihia ki runga e ngā maunga (te ua ā-orographic) e te huihuinga hau ā-rohe rānei.
6. Ngā hau ua: whakaroa i te wā ua
Haunga te ITCZ, he maha ngā rohe o te ekueta e pāngia ana e ngā pūnaha hau mātao, arā, ngā huringa hau o te wā i puta mai i ngā rerekētanga o te wera i waenga i ngā whenua me ngā moana. Hei tauira, i te Tonga-mā-rāwhiti o Āhia, ka kawea mai e te hau mātao o te uru te hau makuku mai i te moana ki uta, ka piki ake te ua i ētahi marama. He maroke ake te hau mātao o te rawhiti i ētahi wāhi, engari nā te mea he motu nui a Initonīhia me te āhua whenua uaua, kāore te pānga i te ōrite.
Mā te taunekeneke i waenga i te hau marangai me te nekehanga o te ITCZ ka roa ake te wā ua: ina kaha te ITCZ, ā, ka kawea mai e te hau marangai te makuku, ka roa pea te ua. I ētahi wāhi, tae noa ki te "wā maroke" ka pāngia e te ua nā te mea kei te makuku tonu te āhuarangi.
7. Te whenua me ngā pānga ā-rohe: ngā maunga, te whenua-moana, me te rere o te hau
He maha ngā momo āhua o ngā rohe o te equator: ngā maunga, ngā papa whenua, ngā awaawa, me ngā takutai moana roa. Ka whakanuia e te āhua o te whenua te ua mā roto i ētahi tikanga:
1. Ua āwhata: ina panaia te hau makuku ki runga i ngā pari maunga, ka whakamatao te hau, ka puta he ua.
2. Hau maunga-awaawa: i te awatea ka rere te hau ki runga i ngā maunga, ā, ka puta he kapua pōkākā; i te pō ka huri te rere.
3. Hau moana-whenua: nā te rerekētanga o te pāmahana o te whenua me te moana ka puta te rere o te hau i ia rā, ā, ka whakaemihia ngā kapua ki ētahi wāhi i ētahi wā.
Ko te tikanga o tēnei huinga ka taea te ua i ngā wāhi maha ahakoa kua pahemo te tihi o te wā ua, ā, ka roa te wā o te "wā mākū".
8. Ngā rerekētanga āhuarangi pērā i te ENSO me te MJO
Ka pāngia hoki te wā ua i ngā rohe o te ekueta e ngā āhuatanga o ia wā, o ia tau hoki. E rua ngā tauira nui:
– ENSO (El Niño–Te Oscillation o te Tonga): He maha ngā wā ka whakaitihia e El Niño te ua i ētahi wāhanga o Initonīhia, ā, ka kaha ake te kitea o te wā maroke, engari ko La Niña ka whakanui ake i te ua, ā, ka roa ake te wā ua.
– MJO (Madden–Julian Oscillation): he ngaru whakawhiti e neke ana mai i te Moana Iniana ki te Moana-nui-a-Kiwa, ā, ka taea te whakanui ake i te ua i roto i te wā 30–60 rā. Ina whiti te wāhanga MJO hohe i te rohe ekueta, ka taea e te ua te piki tere ahakoa he "wā kore" e ai ki ngā toharite āhuarangi.
Ka whakapiki ake ēnei āhuatanga i te uaua, ā, ka whai wāhi atu hoki ki te meka kāore i te mārama te rohe i waenganui i te ua me te wā maroke i ērā i ngā rohe mahana.
Whakamutunga
Ko te roa o te wā ua i ngā rohe o te ekueta ka puta mai i ētahi āhuatanga matua e whakakaha ana tetahi i tetahi: te wera o te rā puta noa i te tau, te tūranga o te ITCZ hei rohe huihuinga e whakaoho ana i te pikinga o te hau, te tohanga Hadley e hanga ana i te ekueta hei rohe o te hau makuku e piki haere ana, te nui o te mamaoa wai mai i ngā moana mahana, me te awe o ngā hau mātao, te āhua o te whenua, me te rerekētanga o te āhuarangi pērā i te ENSO me te MJO. Nō reira, kāore e puta noa te ua i ngā rohe o te ekueta i roto i te wā whaiti, engari ka taea te puta pinepine ake, me ngā tihi ka puta kotahi, e rua rānei i te tau, me ngā rohe o te wā e "pōuri ake ana".
He mea nui te mārama ki ēnei tikanga, ehara i te mea mō te mātauranga whenua anake, engari mō te whakamahere ahuwhenua, te whakahaere i ngā aituā waipuke me te horo whenua, me te urutau ki ngā huringa āhuarangi ka taea te whakarerekē i ngā tauira ua ā muri ake nei.
