View source for Iceberg B-15

{{short description|Largest recorded iceberg by area}}
[[File:Research on Iceberg B-15A by Josh Landis, National Science Foundation (Image 4) (NSF).jpg|thumb|upright=1.35|Northern edge of Iceberg B-15A in the Ross Sea, Antarctica, 29 January 2001]] '''Iceberg B 15''' was the [[List of recorded icebergs by area|largest recorded iceberg by area]].{{refn|Iceberg B-15 is the largest iceberg recorded by satellite photography. In 1956, an [[iceberg]] in the Antarctic was reported to measure an estimated {{convert|333|x|100|km|nmi|abbr=on}}. Recorded before the era of satellite photography, the 1956 iceberg's estimated dimensions are less reliable.<ref name="chicago-trib">{{cite news|last=Goering |first=Laurie |title=Mammoth Iceberg Is Born In Antarctic |newspaper=Chicago Tribune |date=24 March 2000 |url=https://www.chicagotribune.com/2000/03/24/mammoth-iceberg-is-born-in-antarctic/ |access-date=18 February 2014}}</ref>|group=Note}} It measured around {{convert|295|by|37|km|nmi|abbr=off}}, with a surface area of {{convert|11000|km2|sqnmi|abbr=off}}, about the size of the island of [[Jamaica]]. Calved from the [[Ross Ice Shelf]] of [[Antarctica]] in March 2000, Iceberg B-15 broke up into smaller icebergs, the largest of which was named Iceberg B-15-A. In 2003, B-15A drifted away from [[Ross Island]] into the [[Ross Sea]] and headed north, eventually breaking up into several smaller icebergs in October 2005.<ref name="specktor">{{Cite web|url=https://www.space.com/40826-largest-antarctic-iceberg-b15-is-melting.html|title=Antarctica's Largest Iceberg Is About to Die ... Near the Equator|last=Specktor|first=Brandon|date=2018-06-08|website=Space.com|language=en|access-date=2019-08-01}}</ref> In 2018, a large piece of the original iceberg was steadily moving northward, located between the [[Falkland Islands]] and [[South Georgia Island]]. {{As of|August 2023}}, the U.S. [[National Ice Center]] (USNIC) still lists one extant piece of B-15 that meets the minimum threshold for tracking ({{cvt|20|sqnmi|km2|-1|order=flip|disp=or}}).<ref>{{Cite web|title=Antarctic Iceberg Data|url=https://usicecenter.gov/Products/AntarcIcebergs|website=US National Ice Center}}</ref> This iceberg, B-15AB, measures {{cvt|11|x|4|nmi|km|0|order=flip}}; it is currently grounded off the coast of Antarctica in the western sector of the Amery region.<ref name=":0">{{Cite web|date=6 August 2021|title=Icebergs|url=https://usicecenter.gov/pub/Iceberg_Tabular.pdf|website=US National Ice Center}}</ref>

==History==
[[File:B15a a4.jpg|thumb|upright=1.2|Iceberg B-15A four-year journey, July 2002 to March 2006]]
[[File:USCGC Polar Sea at Iceberg B-15A (aft view).jpg|thumb|USCGC Polar Sea nears Iceberg B-15A in January 2001]]
[[File:Iceberg B-15 2018.png|thumb|Iceberg B-15Z route 2014-2018]]
{{maplink|frame=yes|frame-align=|frame-width=250|from=Antarctic Iceberg.map|frame-latitude=-67.88|frame-longitude=-55.66|zoom=9|text=Iceberg B-15AB as of 23 January 2025 ([[:c:Data:Antarctic Iceberg.map|map data]])}}
In the last weeks of March 2000, Iceberg B-15 [[Ice calving|calved]] from the [[Ross Ice Shelf]] near [[Roosevelt Island, Antarctica|Roosevelt Island]], Antarctica.<ref name="nfs">{{cite web |title=Massive Iceberg Peels Off from Antarctic Ice Shelf |work=National Science Foundation |date=22 March 2000 |url=https://www.nsf.gov/od/lpa/news/press/00/pr0012.htm |access-date=17 February 2014 |archive-date=7 February 2023 |archive-url=https://web.archive.org/web/20230207141208/https://www.nsf.gov/od/lpa/news/press/00/pr0012.htm |url-status=dead }}</ref><ref name="atsr">{{cite web|title=Biggest iceberg tracked from space |work=The ATSR Project |date=9 May 2000 |url=http://www.atsr.rl.ac.uk/news/details/09052000/01/index.shtml |access-date=17 February 2014}}</ref> The calving occurred along pre-existing cracks in the ice shelf.<ref name="nfs"/> The iceberg measured around {{convert|295|x|37|km|nmi|abbr=on}}, with a surface area of {{convert|10915|km2|sqnmi|abbr=on}}. Scientists believe that the enormous piece of ice broke away as part of a long-term natural cycle, which occurs every fifty to one hundred years.<ref name="nfs"/> In 2000, 2002, and 2003, Iceberg B-15 broke up into several pieces, the largest of which, B-15A, covered {{convert|6400|km2|sqnmi|abbr=on}} of the sea surface.<ref name="arrigo">{{cite journal|last1=Arrigo |first1=Kevin R. |last2=Van Dijken |first2=Gert L. |title=Annual changes in sea-ice, chlorophyll a, and primary production in the Ross Sea, Antarctica |journal=Deep-Sea Research Part II: Topical Studies in Oceanography |volume=51 |issue=1–3 |pages=117–138 |date=January–February 2004 |doi=10.1016/j.dsr2.2003.04.003|bibcode=2004DSRII..51..117A }}</ref>

In November 2003, after the separation from B-15J, B-15A drifted away from [[Ross Island]] on the open waters of the Ross Sea. In December 2003, a small knife-shaped iceberg, B-15K (about 300&nbsp;km<sup>2</sup>), detached itself from the main body of B-15A and started drifting northward. By January 2005, prevailing currents caused B-15A to drift toward the [[Drygalski Ice Tongue]], a {{convert|70|km|nmi|round=5|adj=mid|-long}} extension of the land-based [[David Glacier]], which flows through the coastal mountains of Victoria Land.<ref name="bbc-pile-up">{{cite web|title=Pile-up as berg hits Antarctica |publisher=BBC |date=19 April 2005 |url=http://news.bbc.co.uk/2/hi/science/nature/4460335.stm |access-date=17 February 2014}}</ref> A few kilometres from the ice tongue, the iceberg became stranded on a shallow [[seamount]] before resuming its northward course.<ref name="new-scientist">{{cite web|last=Bhattacharya |first=Shaoni |title=World's largest iceberg 'goes bump in the night' |work=New Scientist |date=19 April 2005 |url=https://www.newscientist.com/article/dn7283-worlds-largest-iceberg-goes-bump-in-the-night.html#.UwIDSXyYbX4 |access-date=17 February 2014}}</ref> On 10 April 2005, B-15A collided with the ice tongue, breaking off the tip of the ice tongue; the iceberg seemed unaffected by the collision.<ref name="bbc-pile-up"/>

Iceberg B-15A continued to drift along the coast leaving [[McMurdo Sound]]. On 27–28 October 2005, the iceberg ran aground off [[Cape Adare]] in [[Victoria Land]], generating seismic signals that were detected as far away as the [[Amundsen-Scott South Pole Station]]<ref name="macayeal" /><ref name="martin">{{cite journal |last1=Martin |first1=Seelye |last2=Drucker |first2=Robert |last3=Aster |first3=Richard |last4=Davey |first4=Fred |last5=Okal |first5=Emile |last6=Scambos |first6=Ted |last7=MacAyeal |first7=Douglas |title=Kinematic and seismic analysis of giant tabular iceberg breakup at Cape Adare, Antarctica |journal=Journal of Geophysical Research |date=2010 |volume=115 |issue=B6 |pages=B06311 |doi=10.1029/2009jb006700|bibcode=2010JGRB..115.6311M|doi-access= }}</ref> and broke into several smaller pieces, the largest of which was still named B-15A (now measuring approximately {{convert|1700|km2|sqnmi|abbr=on|disp=or}}). Three additional pieces were named B-15P, B-15M, and B-15N. Iceberg B-15A then moved farther up north and broke up into more pieces. These were spotted by air force fisheries patrol{{clarify|reason=which is it, air force or fisheries patrol? and which nation?|date=May 2015}} on 3 November 2006. On 21 November 2006 several large pieces were seen just {{cvt|60|km|nmi|round=5}} off the coast of [[Timaru, New Zealand|Timaru]], New Zealand—the largest measured about {{convert|1.8|km|nmi|frac=8|abbr=on}}, rising {{convert|37|m|ft|round=5|abbr=on}} from the surface of the ocean.

As of 2018, four pieces remained that were large enough to be tracked by the National Ice Center (at least {{cvt|20|sqnmi|km2|order=flip|-1|disp=or}}).<ref name = "specktor"/> One piece, B-15Z, measured {{cvt|10|x|5|nmi|km|0|order=flip}}. It was located in the southern [[Atlantic Ocean]], about {{cvt|150|nmi|km|order=flip}} northwest of [[South Georgia Island]]. As it continued its move northward, the speed of melt increased. Most icebergs do not last long this far north.<ref>{{cite web |url=https://earthsky.org/earth/iceberg-b15z-antarctica-ross-ice-shelf |title=End of the journey for iceberg B-15? |author=Eleanor Imster |date=11 June 2018 |access-date=22 July 2019}}</ref>

By 2020, only two pieces remained large enough to track. B-15aa – a direct remnant of B-15z – was drifting to the east of the island of South Georgia, in the south Atlantic Ocean. B-15ab remained among sea ice along the coast of Antarctica south of Africa.<ref>{{cite web |url=https://www.theweathernetwork.com/ca/news/article/iceberg-a68-breaking-apart-in-new-satellite-images |title=New satellite images reveal Iceberg A-68's days are numbered |author= Scott Sutherland |date=28 April 2020 |access-date=20 May 2021}}</ref> In 2021, B-15ab became the last fragment to remain on the US National Ice Center list of tracked icebergs, still grounded off the coast of Antarctica.<ref name=":0" />

==Effects on Antarctic ecology==
[[File:Iceberg B-15A weather instrument.jpg|thumb|upright=1.2|Researchers installing weather and GPS instruments on Iceberg B-15A, 29 January 2001]]
On 29 January 2001, researchers from the University of Chicago and the University of Wisconsin installed weather and [[Global Positioning System]] instruments on Iceberg B-15A. It was the first time an iceberg had been monitored in this way. The data gathered led to an unprecedented understanding of how giant icebergs make their way through the waters of Antarctica and beyond.

Iceberg B-15A collided  with [[Drygalski Ice Tongue]] on 10 April 2005, breaking off an {{convert|8|km2|sqnmi|frac=4|adj=on|spell=in}} section of the ice tongue. Antarctic maps needed to be redrawn.

B-15A prevented ocean currents and winds from assisting in the 2004–2005 summer break-up of the sea ice in [[McMurdo Sound]], and was an obstacle to the annual resupply ships to three research stations. The [[Drift ice|floe]] was expected{{update inline|date=February 2019}} to cause a catastrophic decline in the population of [[Adélie penguin]]s, as it added considerable distances which parent penguins must travel back from the sea to their chicks. [[Weddell seal]]s and [[skua]]s are also inhabitants of McMurdo Sound and their populations may have been affected as well.

On 21 October 2005 a large storm in the [[Gulf of Alaska]] generated a trans-Pacific Ocean swell that may have contributed to breaking B15-A into many pieces on 27 October 2005.<ref name="macayeal">{{cite journal|last=MacAyeal |first=Douglas R.|title=Transoceanic wave propagation links iceberg calving margins of Antarctica with storms in tropics and Northern Hemisphere |journal=Geophysical Research Letters |volume=33 |issue=17 |pages= L17502|date=12 September 2006 |doi=10.1029/2006gl027235 |bibcode=2006GeoRL..3317502M|display-authors=etal|doi-access=free }}</ref> The swell travelled {{convert|13500|km|nmi|abbr=on}} from Alaska to Antarctica over six days. Scientists are studying this event as an example of how weather in one area can have effects in other parts of the world, and with concern over the effects on [[global warming]].<ref name="npr">{{cite web|last=Harris |first=Richard |title=Alaskan Storm Plays Role of Butterfly for Antarctica |publisher=National Public Radio |date=5 October 2006 |url=https://www.npr.org/templates/story/story.php?storyId=6204027 |access-date=17 February 2014}}</ref>

A more detailed study in 2010, however, shows that the iceberg breakup was principally caused by repeated grounding with near-coastal [[bathymetry]] near [[Cape Adare]], Victoria Land.<ref name="martin" />

==Satellite images==
{|style="margin: 0 auto;"
| [[File:Big iceberg on the loose.jpg|thumb|upright=1.35|Iceberg B-15A drifting toward the [[Drygalski Ice Tongue]] before the collision, 2 January 2005 ([[NASA]])]]
| [[File:B15a figure3b.jpg|thumb|upright=1.35|Iceberg B-15 after break-up, showing B-15M, B-15N, and B-15P, 31 October 2005 ([[Defense Meteorological Satellite Program|DMSP]])]]
|}

==See also==
{{portal|Oceans}}
*''[[Encounters at the End of the World]]'', a [[Werner Herzog]] documentary which contains some footage of B-15

==References==
===Notes===
{{Reflist|group=Note}}

===Citations===
{{Reflist}}

===Further reading===
*{{Cite book|title=Ice Island : Expedition to Antarctica's Largest Iceberg|author=Stone, Gregory S.|publisher=New England Aquarium Press, National Geographic Society|date=2003|isbn=1593730179|location=[[Boston]], Massachusetts|oclc=52739140}}

==External links==
{{commons category|Iceberg B-15}}
* [https://web.archive.org/web/20140222161740/https://earth.esa.int/live/brockmann_archive/2006/MER_RR__1PNPDE20060302_213432_000025672045_00344_20939_3962.htm ESA: Situation Around Balleby Islands; Icebergs B-15A, B-15N, C-19A] {{small|(2 March 2006)}}
* [https://www.esa.int/esaCP/SEMCYK638FE_index_0.html ESA: Envisat Shows Behemoth B-15A Iceberg Breaking Up] {{small|(7 November 2005)}}
* [http://www.nasa.gov/vision/earth/lookingatearth/ice_berg_ram.html NASA: Antarctic Iceberg Gets Stuck] {{Webarchive|url=https://web.archive.org/web/20170616044816/https://www.nasa.gov/vision/earth/lookingatearth/ice_berg_ram.html |date=16 June 2017 }} {{small|(6 January 2005)}}
* [http://earthobservatory.nasa.gov/IOTD/view.php?id=5084 B-15A Iceberg Blocks McMurdo Sound (NASA Earth Observatory)], {{small|(2004-12-15)}}
* [https://www.youtube.com/watch?v=lBfzFt_kgNU Tracking the World's largest Iceberg B 15] {{small|(video)}}

{{Use dmy dates|date=November 2020}}

[[Category:Geography of Antarctica]]
[[Category:Icebergs|B-15]]