Te Mahi a te Radar Āhuarangi me ōna Painga
He hangarau nui te radar huarere i roto i te aroturukitanga huarere o ēnei rā. Mā te radar, ka taea e ngā tohunga huarere te "kite" i ngā mea e tupu ana i te āhuarangi, inā koa mō te aroaro me te nekehanga o te ua, ngā tupuhi, me ētahi atu āhuatanga huarere kino. He tino āwhina ngā mōhiohio mai i te radar huarere mō te matapae huarere mō te wā poto (nowcasting), te whakarato whakatūpato wawe, me te tautoko i te haumaru i roto i ngā momo rāngai pēnei i te rererangi, te kaipuke, te ahuwhenua, me te whakaiti i ngā āhuatanga kino. Hei mārama he aha te whai huatanga o te radar, me mārama tātou ki ōna mātāpono mahi: me pēhea te tuku tohu a te radar, me pēhea te whakaata i aua tohu e ngā ūnga i te āhuarangi, me pēhea te tukatuka i ngā raraunga ki ngā mahere ua me ngā tohu tupuhi.
Te Mārama ki te Radar Āhuarangi
I te nuinga o te wā, ko te radar (Radio Detection and Ranging) he pūnaha e whakamahi ana i ngā ngaru hikohiko hei kimi i ngā mea me te ine i tō rātou tawhiti me ngā āhuatanga. He mea hanga motuhake te radar meteorological hei tirotiro i ngā hydrometeors, arā, ngā matūriki wai i te āhuarangi pērā i ngā pata ua, te whatu, te hukarere, tae atu ki ngā matūriki iti i roto i ngā kapua. Kāore i rite ki te radar rererangi, ki te radar hōia rānei, e whai ana i ngā mea totoka, ka arotahi te radar huarere ki ngā ūnga he maha, he iti, ā, he marara puta noa i te rangi.
Ko te tikanga, ka mahi ngā radar huarere i runga i ngā aukume motuhake, pērā i te S-band, te C-band, te X-band rānei. Ka pā te whiriwhiringa o te aukume ki te whānuitanga me te aro. Ko te S-band he ātete ake ki te whakaiti (te ngoikore o te tohu i te ua) ā, he pai mō ngā tirohanga tawhiti, ko te X-band he aro ake i ngā tawhiti poto engari he ngawari ake ki te ua nui.
Mātāpono Mahi Taketake: Te Tuku me te Whiwhi Whakaata
Ka taea te whakarāpopoto i te mātāpono mahi o te radar huarere ki ngā wāhanga matua e toru: te tukunga o te pāorooro, te taunekeneke ki te ūnga, me te whiwhinga o te tohu whakahoki (echo).
1. Te tukunga o te ngaru reo irirangi
Ka tukuna e te radar ngā ngaru reo irirangi i roto i te ahua o ngā pāoro poto mā roto i tētahi pūihi ka taea te hurihuri me te tohu i ngā koki motuhake (azimuth me te teitei). Ka tere te haere o ēnei pāoro i te tere o te mārama. Nā te mea ehara i te tohu tonu, ka taea e te radar te ine i te wā haere hoki-hoki o te tohu.
2. Te whakaata a ngā hauhautanga
Ina pā te pā o te radar ki tētahi pata wai, ki tētahi maramara huka rānei i te āhuarangi, ka marara ētahi o te kaha o te ngaru ki ngā ahunga rerekē. Ka hoki tētahi wāhanga iti o tēnei kaha marara ki te pūihi radar. Ko te nui o te kaha whakaata ka pāngia e te maha o ngā matūriki, tō rātou rahi, tō rātou āhua (wai/hukapapa), me tō rātou kukū i roto i tētahi rōrahi kua whakaritea.
3. Te whiwhi me te ine i te wā haere
Ka hopukina e te radar te tohu whakahoki, ā, ka ine i te wā e pau ana mai i te wā e tukuna ana te pāoro tae noa ki te whiwhinga mai. Mai i tēnei wā haere, ka tatauhia e te radar te tawhiti o te ūnga mā te whakamahi i tētahi ariā māmā: tawhiti = (tere ngaru × wā haere) / 2. He mea tika te wehewehe mā te rua nā te mea ka haere te tohu i ngā taha e rua.
Ko te hua o tēnei tukanga he mōhiohio e pā ana ki te tawhiti me te kaha o ngā whakaata i tētahi ahunga motuhake. Mā te matawai i ngā ahunga me ngā koki teitei rerekē, ka hangaia e te radar he pikitia toru-ahu o te āhuarangi e karapoti ana.
Ngā Rahinga Matua: Te Whakaata me te Whakatau Tatau Ua
Ko te mōhiotanga tino kitea mai i te radar huarere ko te whakaata (e whakaaturia pinepinetia ana i roto i te dBZ). Ko te whakaata e whakaahua ana i te kaha o te whakaata o te tohu radar e ngā hauhautanga wai. Ko te teitei ake o te uara dBZ, ko te nui ake o te ua pea, ko te nui ake rānei o te rahi o te matūriki (hei tauira, te whatu).
Heoi, ehara te whakaata i te ine tika i te ua, engari he tohu i te kaha o te whakaata. Ka whakamahia e ngā tohunga tētahi whanaungatanga ā-wheako e mōhiotia ana ko te whanaungatanga Z–R (Z mō te whakaata, R mō te tere ua) hei huri i ngā raraunga radar hei whakatau tata i te kaha o te ua. Kāore tēnei whanaungatanga i te rite tonu mō ngā āhuatanga katoa, nā te mea ka pā te momo kapua me ngā āhuatanga ua (ua ua maturuturu, ua paparanga, ua āputaputa) ki ngā hua.
Radar Doppler: Te Ine i te Tere o te Hau me te Hurihanga o te Tupuhi
Ko tētahi whanaketanga matua i roto i te radar huarere ko te whakamahinga o te pānga Doppler. E ine ana te radar Doppler i te whakaata me te nekehanga auau o te tohu whakahoki mai nā te nekehanga o te ūnga ki te radar, ki te matara atu rānei. Mā tēnei ka taea e te radar te whakatau tata i te tere radial (te wāhanga o te tere o te hau i te ahunga o te tirohanga a te radar).
He nui ngā painga o te radar Doppler mō te kimi:
– Te rerenga mai me te rerenga atu i roto i ngā pūtau tupuhi,
– Te kutikuti hau (te huringa ohorere o te tere/te ahunga o te hau),
– Te hurihanga e tohu ana i te tūponotanga o ngā awhiowhio, ngā tupuhi kino rānei (ahakoa he rerekē tēnei i ia rohe, i ia rohe).
Mā ngā mōhiohio tere ka āwhina ngā tohunga huarere ki te mārama ki ngā āhuatanga o te tupuhi, kaua ko te wāhi anake o te ua.
Te Whakapūtātanga-Rua: Te Mōhio ki ngā Momo Ua
He maha ngā radar hou e whakamahi ana i te hangarau whakapūtā-rua, e tuku ana i ngā ngaru i ngā aronga e rua (whakapae me te poutū). Mā te whakatairite i ngā urupare whakaata i roto i ngā whakapūtā e rua, ka taea e te radar te whakatau tata i te āhua me te aronga o ngā matūriki. Mā tēnei ka taea te tautuhi pai ake i:
– te ua me te hukarere me te hukapapa,
– te ua nui me te whatu,
– te wāhi whakauru (paparanga rewa) e puta ai ngā "whiri kanapa".
Ka āwhina hoki te Dual-pol ki te whakapai ake i te tika o ngā whakatau tata ua, me te whakaiti i te kitea hē nā ngā raruraru ehara i te huarere.
Ngā Wero me ngā Here o te Radar Āhuarangi
Ahakoa he tino whai hua, he maha ngā ngoikoretanga o te radar huarere:
– Te whakaitiiti: ka taea e te ua nui te whakaiti i te tohu, inā koa i te roopu-C me te roopu-X, kia ahua ngoikore ai te rohe i muri i te ua nui i tōna āhua tuturu.
– Ngā mea pōrearea: ka taea e ngā whakaata mai i ngā mea kāore e pā ana ki te huarere pērā i ngā maunga, ngā whare, ngā ngaru o te moana te whakararuraru i ngā pānui.
– Ārai hihi: ka kapi pea tētahi wāhanga o te wāhi tirotiro i ngā ārai whenua.
– Te teitei o te hihi radar: ko te tawhiti atu i te radar, ko te teitei ake o te hihi radar i te mata nā te piko o te whenua, nō reira, kāore pea e tino tika ngā tirohanga tata ki te mata i ngā tawhiti roa.
Nō reira, he maha ngā wā ka honoa ngā raraunga radar me ngā raraunga amiorangi, ngā teihana ua, me ngā tauira huarere tau hei whakaputa i ngā mōhiohio pono ake.
Ngā Painga o te Radar Āhuarangi
He whānui ngā painga o te radar huarere, ā, ka kitea tonutia i te ao:
1. Whakatūpato wawe mō te huarere kino
Ka taea e te radar te aro turuki tere i te tipu o ngā kapua convective, ā, ka tukuna he whakatūpato mō te ua nui, ngā whatitiri, me ngā waipuke ohorere i ngā wā mai i ngā meneti ki ngā hāora.
2. Te tuku pānuitanga inaianei me ngā matapae poto rawa
Mā te whai i te nekehanga o ngā pūtau ua, ka taea e te radar te whakatau tata i te wā e ua ai ki tētahi rohe, te kaha o te ua, me te roa pea o te ua.
3. Te haumaru o te rererangi me te kawe waka
Ka whakamahia e ngā taunga rererangi me ngā kamupene rererangi ngā mōhiohio radar hei karo i ngā tupuhi, i ngā aueuetanga e pā ana ki te convection, me te kutikuti hau. I te moana, ka tautokohia e te radar ngā whakatūpato tupuhi mō ngā kaipuke.
4. Te whakaiti i ngā āhuatanga kino o te rangi
Mā ngā raraunga radar ka āwhina ngā mana whakahaere ki te aroturuki i te ua nui i ngā wāhi o te awa, kia taea ai te whakatau i ngā whakaritenga whakawātea i te wā tika, te whakatuwheratanga rānei i ngā kēti waipuke.
5. Te whakahaere i ngā rauemi ahuwhenua me te wai
Mā te mārama ake ki te tohatoha o te ua, ka taea te whakapai ake i te whakahaerenga o te whakamakuku me te whakahaere i ngā puna wai, ā, ka taea hoki te urutau ake i te whakamahere whakato.
6. Rangahau āhuarangi me te rangi
He pai ngā rekoata radar mō te wā roa mō te ako i ngā tauira tupuhi, ngā āhuatanga ua o te wā, me te aromatawai i ngā tauira huarere.
Te Katinga
Ka mahi te radar huarere mā te tuku i ngā ngaru reo irirangi me te tātari i ō rātou whakaata mai i te wai me ngā matūriki hukapapa i te āhuarangi. Mā tēnei tukanga ka taea e te radar te mahere i te kaha o te ua, te mārama ki ngā whanaketanga awha mā te Doppler, tae atu ki te tautuhi i ngā momo ua mā te whakawehenga-rua. Ahakoa ngā herenga pēnei i te whakaiti me te raruraru, ko te radar tonu te pou tuarā o te aroturuki huarere poto. Me ōna painga maha—mai i te whakatūpato wawe ki te tautoko kawe waka me te whakaiti i ngā aituā—he hangarau nui te radar huarere mō te whakapai ake i te haumaru o te iwi me te manawanui ki ngā huringa huarere tere me te tino kino.
