page_title: Polar see-saw
hierarchical_section_title: Polar see-saw
caption_attribution_description: From the en:Vostok and en:EPICA (en:Antarctica) and GRIP (en:Greenland) en:ice cores: d-D and d-o-18, last 40kyr. Horizontal axis: time before 1950 (I think). Vertical axis: d-D (or delta-O-18 * 10). By William M. Connolley. See en:Temperature record. Note that d-D or d-O-18 is a en:proxy for temperature: more negative is colder; the period from 20 to 10 kyr shows the rise in temperature at the end of the last ice age. Note the en:Dansgaard-Oeschger events visible in the GRIP core but barely, if at all, in the Antarctic cores. d-D and d-O-18 tend to be "the same" (http://www.iceandclimate.nbi.ku.dk/publications/papers/pdfs/242.pdf/) though a factor of 8 comparison would be better than 10. Updated version of en:Image:Epica-vostok-40kyr.png including GRIP, from: GRIP: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/ngrip/isotopes/ngrip-d18o-50yr.txt (ss09sea timescale) EPICA: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/edc_dd.txt (EDC2 timescale) Vostok: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/deutnat.txt (GT4 timescale) Code: a=readfromfile('edc_dd1.txt',col=6,ign=1) b=readfromfile('vostok_deutnat1.txt',ign=1,col=4) c=readfromfile('grip.txt',ign=10,col=2) !p.multi=[0,1,2] ep=reform(a(5,*)) vo=reform(b(2,*)) gr=reform(c(1,*))*10 plot,a(4,*),ep,title='delta-o18 vs age',/xs,xr=[0,40000],ymarg=[2,5],yr=makerange([ep,vo,gr]),th=3 oplot,col=3,b(1,*),vo,th=3 oplot,col=2,c(0,*),gr,th=3 oplot,a(4,*),ep,th=3 add_key,/rig,['EPICA (Antarctic)','Vostok (Antarctic)','GRIP (Greenland)'],[!p.color,3,2],th=3,/top
context_page_description: The polar see-saw is the phenomenon that temperature changes in the northern and southern hemispheres may be out of phase. The hypothesis states that large changes, for example when the glaciers are intensely growing or depleting, in the formation of ocean bottom water in both poles take a long time to exert their effect in the other hemisphere. Estimates of the period of delay vary, one typical estimate is 1500 years. This is usually studied in the context of ice cores taken from Antarctica and Greenland.
context_section_description: The polar see-saw (also: bipolar seesaw) is the phenomenon that temperature changes in the northern and southern hemispheres may be out of phase. The hypothesis states that large changes, for example when the glaciers are intensely growing or depleting, in the formation of ocean bottom water in both poles take a long time to exert their effect in the other hemisphere. Estimates of the period of delay vary, one typical estimate is 1500 years. This is usually studied in the context of ice cores taken from Antarctica and Greenland.
caption: The warming during the Younger Dryas is out of phase between the two hemispheres.
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