samudra tal

samudra tal se ooainchaai dikhaata ek board

samudra tal ya ausat samudra tal (angreji:Mean sea level) samudra ke jal ke upari satah ki ausat ooainchaai ka maan hota hai. iski ganana jvaar-bhaate ke kaaran hone vaale samudri satah ke utaar chadhaav ka lambe samay tak prekshan karke usaka ausat nikaal kar ki jaati hai. ise samudra tal se ooainchaai (MSL-Metres above sea level) mein vyakt kiya jaata hai.

iska prayog dharaatal par sthit binduon ki ooainchaai maapane ke liye sandarbh tal ke roop mein kiya jaata hai. iska upayog uddayan mein bhi hota hai. uddayan mein samudra ki satah par vaayumandaleeya daab ko vaayuyaanon ke udaan ki uainchaai ke sandarbh (daitam) ke roop mein upayog kiya jaata hai.

anukram

maapan

samudra tal ka sahi maapan kai kaaranon se mushkil maana jaata hai. ismein sabse pramukh kaaran hai iski parivrtanasheelata. samudri satah vibhinn kaarakon se prabhaavit hoti hai jinmein mausami kaarak ise alpakaal mein aur jalavaayaveeya kaarak deergh kaal mein parivrtit karte rahate hain. antariksh mein chandrama aur soorya ki sthitiyaaain ek chakreeya roop mein jvaar-bhaate ka kaaran banti hain. iske alaava plate vivrtaniki aur samasthitik kaaranon se samudra taton ki ooainchaai mein bhi badlaav ke kaaran aabhaasi samudra tal parivartan darj kiya ja sakta hai.

ooainchaaimaapi upagrahon se iske maapan mein kaafi shuddhata aayi hai. isse pehle ise jvaaramaapi ke prekshanon ka ausat nikaal kar maapa jaata tha. udaaharan ke liye United kingadam mein zero leval 1915 aur 1921 ke beech kaurnavaal ke nyoolin samudra tat par maape gaye ausat samudra tal ko maana jaata hai. isse pehle livrapool ke Victoria dauk se yeh ganana ki jaati thi.

1992 mein naasa(NASA) aur fraanseesi raashtreeya antariksh adhyayan kendra (CNES) ke sanyukt abhiyaan topeks/posaaidan ke baad upagrah dvaara samudra tal ke maapan ki kshamata aur shuddhata mein vruddhi hui. iske baad do anya upagrah Jason-1 aur Jason-2 bhi chhode gaye.

kaalik parivartan

alpakaalik parivartan
  1. jvaar-bhaata dvaara (chakreeya),
  2. vaayudaab parivartan dvaara (aniyamit),
  3. pavan ka veg aur laharein (svel/sarj)(aniyamit)
deerghakaalik parivartan
  1. jalavaayu parivartan
  2. plate vivrtaniki

kshetreeya vividhta

1. samudra. 2. sandarbh elipsoid.
3. sthaaneeya saahul rekha. 4. mahaadveep. 5. jyoid

pruthvi ki oopari parat bhooparpati ka ghanatv sabhi jagah ek saamaan naheen hai. yahi kaaran hai ki alag-alag jagahon par gurutvaakarshan mein vividhta paayi jaati hai aur tadanusaar samudra tal mein bhi vividhta milti hai.

ooainchaai naapane hetu sandarbh

samatal sarvekshan mein

samatal sarvekshan, jismein pruthvi ki golaabheeya aakruti ko na ginte hue satah ko ek samatal satah maan kar sarvekshan kiya jaata hai, saamaanyat: kisi ek bindu ka samudra tal se ooainchaai ko aadhaar bana kar baaki binduon ki ooainchaaiyaaain usaki tulana mein nikaali jaati hain. ise saamaanyat: talamaapan (leveling) se maapa jaata hai.

jiyodetik sarvekshan mein

jiyodetik sarvekshan mein pruthvi ki lagbhag golaabheeya aakruti ko ganana mein rakhate hue kisi kshetr ka sarvekshan kiya jaata hai. vastut: pruthvi ki is prithivyaakaar aakruti ko samudra tal dvaara hi paribhaashit kiya jaata hai aur iski ganana jiyodetik sarvekshan ka pramukh vishay hai. vartamaan samay mein vaishvik roop se istemaal hone wala sandarbh tal WGS-84 hai jis ki ganana world jiyodetik sarve ne 1984 mein ki thi.

vimaanan evam radio mein

vimaanan mein vaayuyaanon ki ooainchaai ko bhi samudra tal se maapa jaata hai. alteemeetar ek aisa yantr hota hai jo ooainchaai badhne ke saath saath vaayudaab mein hone vaale hraas ko maap kar vimaan ki samudra tal se ooainchaai bataata hai.

rediyon tower aur enteena ki ooainchaai yeh tay karti hai ki uske prasaaran ko kitne kshetr mein praapt kiya ja sakta hai. ise bhi samudra tal se oordhvaadhar doori arthaat ooainchaai mein (AMSL-evarej meter abav si leval) mein vyakt kiya jaata hai.

samudra tal parivartan

Water cycles between ocean, atmosphere and glaciers.
do anumaanit samudra tal maapon ka tulanaatmak chitran (pichhle 500 Ma mein)
pichhle himyug ke baad se samudra tal mein parivartan (meter mein)

alpakaalik aur chakreeya parivaartan

alpaavadhik parivartan kai kaaranon se hote hain aur kuchh minton se lekar 14 maheene tak ki avaadhi ke ho sakte hain:

chakreeya samudra tal parivartan
dainik/arddhadainik jvaar-bhaata 12–24 h P 0.2–10+ m
deerghakaalik jvaar
ghoornan janya parivartan (chaindalar vabal) 14 maheene P
mausami aur samudravaijnyaaanik utaar-chadhaav
vaayudaab ghanton se lekar maheenon mein −0.7 to 1.3 m
pavaane (storm sarj) 1–5 din Up to 5 m
vaashpeekaran aur varshan (deerghakaalik bhi ho sakta hai) dinon se hafton
samudri satah sthalaakruti (changes in water density and currents) dinon se hafton Up to 1 m
L nino/dakshini parivartan 6 mo every 5–10 yr Up to 0.6 m
ritukaalik utaar-chadhaav
ritvik jal ka vitran (Atlantic, Pacific, Indian)
jaleeya satah ke dhaal mein ritukaalik badlaav
nadi jalavaah/baadh ityaadi 2 months 1 m
ritukaalik samudri jal ghanatv parivartan (temperature and salinity) 6 months 0.2 m
Seiches
shi'sh (sthir tarange) Minutes to hours Up to 2 m
Earthquakes
sunaami (generate catastrophic long-period waves) Hours Up to 10 m
thal ki ooainchaai ke star mein achaanak parivartan Minutes Up to 10 m

praacheen parivartan

vartamaan kaaleen parivartan

inhein bhi dekhein

sandarbh


baahari kadiyaaain