查看“︁北極高原”︁的源代码

{{MarsGeo-Plains
|name=北極高原<br>Planum Boreum
|image=[[File:Mars NPArea-PIA00161.jpg|200px]]
|caption=[[海盜號]]照片拼接成的北極高原和週邊區域
|location=
|latitude=88.0
|N_or_S=N
|longitude=15.0
|E_or_W=E
|area=
|discoverer
|naming=
}}
'''北極高原'''（[[拉丁語]]：'''Planum Boreum'''，北方的平原；'''Planum'''是指高海拔的平原或高原）是位於火星北極區的高原。範圍從大約80°N向北延伸，中心點大約位於{{Coord|88.0|15.0|globe:Mars}}。在這個高原周圍的區域是平坦無明顯地表特徵的低地，向南延伸約1500公里且佔據火星北半球大部分區域的[[北方大平原]]<ref>[http://planetarynames.wr.usgs.gov/jsp/FeatureNameDetail.jsp?feature=64923] {{Wayback|url=http://planetarynames.wr.usgs.gov/jsp/FeatureNameDetail.jsp?feature=64923 |date=20070310225509 }} and [http://planetarynames.wr.usgs.gov/jsp/FeatureNameDetail.jsp?feature=66502] {{Wayback|url=http://planetarynames.wr.usgs.gov/jsp/FeatureNameDetail.jsp?feature=66502 |date=20100628160626 }} give Vastitas Borealis starting at 54.7°N and Planum Boreum at 78.5°N. The radius of Mars is approximately 3400 km, so <math>d=\frac{78.5 - 54.7}{360}\times 2 \pi\ \times 3400\mbox{ km} = 1412\mbox{ km} </math></ref>。1999年[[哈伯太空望遠鏡]]拍攝到了北極高原[[氣旋]]的影像。該氣旋直徑約1750公里，並有一個直徑320公里的明顯[[風眼]]<ref>{{cite web|url=http://hubblesite.org/newscenter/archive/releases/1999/22/text/|title=Colossal Cyclone Swirls near Martian North Pole|accessdate=2006-11-01|archive-date=2012-02-12|archive-url=https://web.archive.org/web/20120212143121/http://hubblesite.org/newscenter/archive/releases/1999/22/text/|dead-url=no}}</ref>。

==冰帽==
[[File:MRO image of Mars North Pole.jpg|left|thumb|150px|[[火星侦察轨道器]]拍攝位於北極冰帽的[[北極峽谷]]（Chasma Boreale）一側假色影像。淺棕色代表表面覆蓋灰色塵埃的地層，藍色地層則是含有水冰和乾冰的地層。規則裂縫指出水冰高度集中。]]
[[File:PSP 001406 2680 ChasmaBoreale.jpg|thumb|200px|[[HiRISE]]拍攝到火星北極冰帽的撞擊坑]]
北極高原是以水冰和乾冰組成的永久冰帽所在地。冰帽的體積是120萬[[立方公里]]，覆蓋面積相當於[[德克薩斯州]]1.5倍。直徑600公里，最大深度約3公里<ref>{{cite web |url=http://ltpwww.gsfc.nasa.gov/tharsis/agu_f98.html |title=Laser provides first 3-D View of Mars' North Pole |accessdate=2006-11-01 |archiveurl=https://web.archive.org/web/20061017122112/http://ltpwww.gsfc.nasa.gov/tharsis/agu_f98.html |archivedate=2006-10-17 |deadurl=yes }}</ref>。冰帽的螺旋狀凹陷區域主要是因為受到強勁的風侵蝕和乾冰昇華造成<ref>{{cite news|url=http://news.bbc.co.uk/2/hi/science/nature/2280991.stm|title=Martian 'wobbles' shift climate|accessdate=2006-11-01|publisher=[[BBC News]]|date=2002-09-25|archive-date=2006-06-14|archive-url=https://web.archive.org/web/20060614084935/http://news.bbc.co.uk/2/hi/science/nature/2280991.stm|dead-url=no}}</ref>。

火星北極冰帽在春季中期的表面成分（在冬季季節性乾冰累積之後）已經被軌道探測器研究過。冰帽外緣則混雜塵土（重量的0.15%），不過絕大多數是水冰。越接近北極點表面的水冰減少，並被乾冰取代。而冰的純度也增加。在北極點的季節性冰則幾乎都是乾冰和少量的塵土，以及30 [[百萬分率|ppm]]的水冰<ref>{{cite web|url=http://www-mars.lmd.jussieu.fr/granada2006/abstracts/Giuranna_Granada2006.pdf|title=Spatial variability and composition of the seasonal north polar cap on Mars|accessdate=2006-11-01|archive-date=2006-12-10|archive-url=https://web.archive.org/web/20061210100329/http://www-mars.lmd.jussieu.fr/granada2006/abstracts/Giuranna_Granada2006.pdf|dead-url=yes}}</ref>。

2007年發射的[[鳳凰號火星探測器]]於2008年5月25日登陸火星的[[北方大平原]]。火星極區冰帽已被[[傑佛瑞·蘭迪斯]]<ref>G. Landis, [http://www.sff.net/people/Geoffrey.Landis/pole.html Polar Landing Site for a First Mars Expedition] {{Wayback|url=http://www.sff.net/people/Geoffrey.Landis/pole.html |date=20080511191239 }} Founding Convention of the Mars Society, August 13–16, 1998, [[科羅拉多大學博爾德分校|University of Colorado at Boulder]] in [[博爾德 (科羅拉多州)|Boulder, CO]]</ref>和[[查爾斯·科克爾]]<ref>[[Project Boreas]] C. Cockell (editor), [http://www.bis-spaceflight.com/sitesia.aspx/page/170/id/980/l/en-gbBoreas Project Boreas - A Station for the Martian Geographic North Pole]{{dead link|date=2017年11月 |bot=InternetArchiveBot |fix-attempted=yes }}, The [[英國星際學會|British Interplanetary Society]]（2006）</ref>提議是未來載人火星任務的登陸地點。
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==地形特徵==
[[File:PoloNorteMarteTopologico.png|thumb|200px|火星北極的地形圖，注意北極高原比周圍平坦無明顯特徵的地區來得高。點選可看大圖。]]

北極高原的主要地理特徵是被稱為[[北極峽谷]]的巨大裂縫或峽谷。該峽谷寬度可達100公里，深度可達2公里<ref>{{cite web|url=http://www.esa.int/SPECIALS/Mars_Express/SEM8T86Y3EE_0.html|title=Fly over the Chasma Boreale at Martian north pole|publisher=[[European Space Agency]]|accessdate=2006-11-01|archive-date=2006-10-08|archive-url=https://web.archive.org/web/20061008190217/http://www.esa.int/SPECIALS/Mars_Express/SEM8T86Y3EE_0.html|dead-url=no}}</ref><ref name=usgs>{{cite web|url=http://pubs.usgs.gov/sim/2005/2888/sim2888pamphlet.pdf|accessdate=2006-01-11|title=Geologic Map of the Northern Plains of Mars|publisher=[[美國地質調查局|United States Geological Survey]]|archive-date=2006-10-09|archive-url=https://web.archive.org/web/20061009032924/http://pubs.usgs.gov/sim/2005/2888/sim2888pamphlet.pdf|dead-url=no}}</ref>。相較之下[[科羅拉多大峽谷|大峽谷]]在某些段約1.6公里深，長度446公里，但最寬處只有約24公里。北極峽谷切穿極區沉積物和冰，類似的狀況在[[格陵蘭]]也可發現。

在[[北極峽谷]]西側北極高原和[[北方大平原]]之間是不規則狀的陡坡，稱為[[特纽依斯峭壁]]。該斜坡高度高達1公里。其他區域北方大平原和北極高原之間則是一群台地和地槽。

北極高原被自75°N到85°N的大範圍[[沙丘]]地包圍。這些沙丘地叫做[[奧林比亚沙丘地]]、[[阿瓦洛斯沙丘群]]和[[极北沙丘群|許珀耳玻瑞亞沙丘群]]。最大的奧林匹亞沙丘地範圍橫跨100°E到240°E，阿巴洛斯沙丘地橫跨261°E到280°E，而許珀耳玻瑞亞沙丘地則橫跨311°E到341°E<ref>{{cite web|url=http://planetarynames.wr.usgs.gov/jsp/AdvanceSearch2.jsp?system=ALL&system=ALL&fname=undae&ft=ALL&diamgt=&diamlt=&nlat=&slat=&wlon=&elon=&lonDirection=null&adb=&ade=&as=ANY&cont=&ethn=&refN=&refT=&quad=&map=&QuickSearch=true&sort=AP|title=USGS Astro: Search Planetary Nomenclature|accessdate=2006-11-01|archive-date=2019-09-13|archive-url=https://web.archive.org/web/20190913110147/https://planetarynames.wr.usgs.gov/?system=ALL&system=ALL&fname=undae&ft=ALL&diamgt=&diamlt=&nlat=&slat=&wlon=&elon=&lonDirection=null&adb=&ade=&as=ANY&cont=&ethn=&refN=&refT=&quad=&map=&QuickSearch=true&sort=AP|dead-url=no}}</ref>。參見[[地球外的沙丘地列表]]。

==雪崩==
[[File:Mars avalanche Feb 19.jpg|thumb|200px|left|火星上的[[雪崩]]假色照片。]]

2008年2月[[火星侦察轨道器]]的HiRISE拍攝到發生在一個高700公尺峭壁的四次雪崩。雪崩後由細顆粒土壤產生的雲寬度180公尺，自峭壁底部延伸190公尺。偏紅的地層被認為是富含水冰的地層，而白色的地層是季節性的乾冰霜。這次山崩被認為是自最上方的紅色地層開始。後續觀測確定它的本質是[[泥石流]]<ref>{{cite web|url=http://www.sciam.com/gallery_directory.cfm?photo_id=7B82B079-C057-F0CF-D15B555DBA34B1CF|publisher=[[科學美國人|Scientific American]]|date=2008-03-04|accessdate=2008-03-05|title=Avalanche on Mars|archive-date=2008-03-08|archive-url=https://web.archive.org/web/20080308183343/http://www.sciam.com/gallery_directory.cfm?photo_id=7B82B079-C057-F0CF-D15B555DBA34B1CF|dead-url=no}}</ref><ref>{{cite web|url=http://www.jpl.nasa.gov/news/news.cfm?release=2008-036|accessdate=2008-03-05|date=2008-03-03|title=NASA Spacecraft Photographs Avalanches on Mars|archive-date=2008-03-06|archive-url=https://web.archive.org/web/20080306060426/http://www.jpl.nasa.gov/news/news.cfm?release=2008-036|dead-url=yes}}</ref>
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==參見==
*[[南極高原 (火星)|南極高原]]，位在火星南極區
*[[北方大平原]]
*[[火星水文]]

==參考資料==
{{Reflist|2}}

==外部連結==
*[http://www.esa.int/SPECIALS/Mars_Express/SEM8T86Y3EE_0.html Fly over the Chasma Boreale at Martian north pole]{{Wayback|url=http://www.esa.int/SPECIALS/Mars_Express/SEM8T86Y3EE_0.html |date=20100906145634 }} - courtesy of [[火星快車號|Mars Express]]
*[http://pubs.usgs.gov/sim/2005/2888/ Geologic Map of the Northern Plains of Mars]{{Wayback|url=http://pubs.usgs.gov/sim/2005/2888/ |date=20110604174719 }}
*[http://hirise.lpl.arizona.edu/PSP_007338_2640 HiRISE image of Martian landslides]{{Wayback|url=http://hirise.lpl.arizona.edu/PSP_007338_2640 |date=20090818043852 }}
*[http://hiroc.lpl.arizona.edu/images/PSP/PSP_001370_2505/ HiRISE image of permanent ice mound separated from cap]{{Wayback|url=http://hiroc.lpl.arizona.edu/images/PSP/PSP_001370_2505/ |date=20110716182517 }}
*Various [[HiRISE]] images of the north polar ice cap: [http://hiroc.lpl.arizona.edu/images/PSP/PSP_001412_2650/]{{Wayback|url=http://hiroc.lpl.arizona.edu/images/PSP/PSP_001412_2650/ |date=20110716182551 }} [http://hiroc.lpl.arizona.edu/images/PSP/PSP_001334_2645/color.html]{{Wayback|url=http://hiroc.lpl.arizona.edu/images/PSP/PSP_001334_2645/color.html |date=20110716182405 }} [http://hiroc.lpl.arizona.edu/images/PSP/PSP_001513_2650/]{{Wayback|url=http://hiroc.lpl.arizona.edu/images/PSP/PSP_001513_2650/ |date=20110716182607 }} [http://hiroc.lpl.arizona.edu/images/PSP/PSP_001406_2680/]{{Wayback|url=http://hiroc.lpl.arizona.edu/images/PSP/PSP_001406_2680/ |date=20110716182625 }}

{{火星}}

[[Category:火星平原]]