मरुस्थल

thumb|300px|marusthal marusthal ya 'registan' ko bhugolashastr ke anusar aisi sthalakriti ke roop mean paribhashit kiya gaya hai, jahaan varsha, bauchhar, him, barph adi roopoan mean, bahut kam lagabhag 250 mi.mi. tak hoti hai. ek aur paribhasha ke anusar registan ya marusthal ek banjar, shushk kshetr hai, jahaan vanaspati nahian ke barabar hoti hai, yahaan keval vahi paudhe panap sakate haian, jinamean jal sanchay karane ki athava dharati ke bahut niche se jal prapt karane ki adabhut kshamata ho. yahaan par ugane vale paudhe zamin ke kafi niche tak apani j doan ko vikasit kar lete haian, jis karan niche ki nami ko ye asani se grahan kar lete haian. mitti ki patali chadar, jo vayu ke tivr veg se palatati rahati hai aur jisamean ki khad-mitti pray: ka abhav hota hai, vah upajaoo nahian hoti. in kshetroan mean vashpikaran ki kriya se vashpit jal, varsha se prapt kul jal se adhik ho jata hai, tatha yahaan varsha bahut kam aur kahian-kahian hi ho pati hai. aantarkatika kshetr ko chho dakar any sthanoan par sookhe ki avadhi ek sal ya isase bhi adhik bhi ho sakati hai. is kshetr mean behad shushk v garm sthiti kisi bhi paidavar ke lie upayukt nahian hoti hai.

prakar

vishv ke pramukh marusthal

nam	desh	kshetraphal (kimi.)
sahara	uttari aphrika	9065000
libayan	uttari aphrika	1683500
astreliyan	aaustreliya	1554000
gret viktoriya	aaustreliya	338,000
atakama	uttari chili	180000
peantagoniyan	arjeantina	6,73,000
siriyan	arab	323800
arab registan	arab	230,00,00
gobi	mangoliya	1036000
rab al khali	arab	647500
kalahari	botsvana	518000
gret seandi	aaustreliya	3,40,000
takala makan	chin	3,27,000
arunata	aaustreliya	310800
karakum	dakshin-pashchimi turkistan	2,97,900
noobiyan	uttari aphrika	259000
thar	uttari-pashchimi bharat	259000
kijilakul	madhy turkistan	233100
tanami	aaustreliya	37,500
negev	ijarail	12,170
mojave	amerika	-
di gret besin	amerika	4,09,000
namib	namibiya	1,35,000
deth vaili	kailiforniya	-
chihohua	uttari amerika	5,18,000
simpasan	aaustreliya	170,000
gibsan	pashchimi aaustreliya	156,000
stuart patharila	aaustreliya	-

vibhinn prakar ki bhaugolik sthalakritiyoan ke adhar par marusthal nimn prakar ke hote haian-

1. vastavik marusthal- isamean baloo ki prachurata paee jati hai.
2. patharile marusthal- isamean kank d-patthar se yukt bhoomi paee jati hai. inhean aljiriya mean reg tatha libiya mean serir ke nam se jana jata hai.
3. chattani marusthal- isamean chattani bhoomi ka hissa adhikadhik hota hai. inhean sahara kshetr mean hamada kaha jata hai.

vishv mean jitane bhi prakar ke registan haian, utane hi prakar ki unaki vargikaran paddhatiyaan prachalit haian. registan thande v garm donoan prakar ke hote haian. dharati par tarah-tarah ke garm v thande registan haian. jis kshetr ka ausat tapaman 30 digri selsiyas se adhik hota hai, unhean 'garm registan' kaha jata hai. prayah adhruviy kshetroan ke registan garm hote haian. adhruviy registanoan mean pani bahut hi kam hota hai, isalie ye kshetr garm hote haian. prayah shushk aur atyadhik shushk bhoomi vastav mean registan ko aur ardhashushk bhoomi ghas ke maidanoan ko darshati haian. jin kshetroan mean shit rritu ka ausat tapaman shoony digri selsiyas se kam hota hai ve ilake 'thande registan' ya 'shit registan kahalate' haian. dhruviy kshetr ke registan thande hote haian tatha varsh bhar barph se dhake rahate haian. yahaan varsha nagany hoti hai tatha dharati ki satah par sadaiv barph ki chadar si bichhi rahati hai. jin kshetroan mean jamav biandu ek vishesh mausam mean hi hota hai, un thande registanoan ko 'tuandra' kahate haian. jahaan poore varsh tapaman shoony digri selsiyas se kam rahata hai, aise sthan sadaiv barph achchhadit rahate haian. dhruviy pradesh ke alava any kshetroan mean jal ki upasthiti bahut kam hone ke karan registan garm hote haian.

varsha ki sthiti

prayah registan ka nirdharan varshik varsha ki matra, varsha ke kul dinoan, tapaman, nami adi karakoan ke dvara kiya jata hai. is sanbandh mean san 1953 mean yoonesko ke lie pevaril migs dvara kiya gaya vargikaran lagabhag sarvamany hai. unhoanne varshik varsha ke adhar par vishv ke registanoan ko 3 vibhinn shreniyoan mean vargikrit kiya hai.

1. ati shushk bhoomi - jahaan lagatar 12 mahinoan tak varsha nahian hoti tatha kul varshik varsha ka ausat 25 mi.mi. se kam hi rahata hai.
2. shushk bhoomi - jahaan par varsha 250 mi.mi. prati varsh se kam ho.
3. ardhashushk bhoomi - jahaan par ausat varshik varsha 250 se 500 mi.mi. se kam hoti hai.

in sab batoan ke adhar par bhi keval varsha ki kami hi kisi kshetr ko registan ke roop mean nirdharit nahian kar sakati. udaharan ke lie phoniks v erijona kshetroan mean varshik varsha ka star 250 mi.mi. se kam hota hai, lekin un kshetroan ko registan ki manyata prapt hai. doosari or alaska brok reanj ke uttari dhalan, mean bhi varshik varsha ka star bhi 250 mi.mi. se kam hota hai, parantu in kshetroan ko registan nahian mana jata hai.

vargikaran

bhoomandaliy sthiti tatha mausam ke prabhav ke adhar par registan ko nimn prakar se vargikrit kiya ja sakata hai-

1. vyaparik pavan registan
2. madhy akshaansh registan
3. varshavrishti registan
4. tatiy registan
5. manasooni registan
6. dhruviy registan

sthalakriti

registani bhoomi ko kisi vishesh registan praroop ke adhar par bhi vargikrit kiya ja sakata hai. samanyatah is vargikaran ke anusar registan 6 prakar ke mane gaye haian-

1. parvatiy aur droni registan
2. shaili registan - ye pathar jaisi sthalakriti ke hote haian.
3. regs - chattani kshetr
4. argas - ye ret ke vishal samudr se nirmit hote haian.
5. aantaraparvatiy droniyaan
6. utkhat bhoomi

panne ki pragati avastha

adhar

prarambhik

madhyamik

poornata

shodh