Accumulation, Ablation, and Oxygen Isotope Variations on the Queen Elizabeth Islands Ice Caps, Canada

Abstract

ABSTRACT. Measurements made on traverses ove r ice caps in the Queen Elizabeth Isla nds show that there is a region of very high ~cc umulation ( > 40 g c m -2 year-I) on the slopes facing Baffin Bay and one of low a ccumulation « 15 g cm -" year-I) in the interior parts of northern Ellesmere Isla nd . Abla tion rates in summer show much less regiona l va riation over the same ice caps except for lo w er rates along th e north-west edge of the islands and poss ibly on the Baffin Bay slopes as well. However, th ere is a stronger rela tionship between ablation and elevation which is exponentia l below the firn line. From the fractiona l 18 0 content of the snow it is shown that Baffin Bay contributes significant amounts of moisture ( > 20 % of the tota l) to the Ba ffin Bay slopes. In addition the Arctic O cean is see n as an other, but much less significant, m oisture source. The 8 18 0 d a ta show two e ffects on the condensation processes-an orographic one (i. e. adiabatic cooling) and a distan ce-from-source effect (isobaric cooling) where the sourCe is somewhere to th e south-east of the islands. Cepe ndant, il y a une plus fo rte rela tion entre l' a blation et l'altitude qui est d e forme ex pone ntiell e en dessous d e la ligne des neves. A pa rtir de la tene ur e n 18 0 d e la ne ige, on montre que la Ba ie d e Baffin contribue significativement it l'approvisionnement en eau (plus d e 20~o du tota l) des pentes de la Baie d e Baffin . D e plus, l' O cean Arctique appa ra it comme un e a utre source d 'eau m a is beaucoup moins importanle. La vari a tion d e te ne ur en 18 0 met e n evidence deux effe ts sur les processus d e condensation : un effet orographique (c'est it dire de refroidi sseme nt ad iaba tique) e t un effet de dista nce it la source (r efroidissement isoba rique) lorsque la source est quelque part vel's le Sud-Est d es il es . Z USAMME NFASS U NG. Akkul1llllation, Ablation 1I1ld Schwankwzgen des Gehalts all S auerstoif-Isotopell m u Eiskappender Queen E li z abeth I slalzds, Kan ada. Mess ungen bei iiberquerungen von Eiskappen auf den Queen Elizabeth Islands zeige n, dass d ort ein Gebie t sehr h oher Akkumul a tion ( > 40 g cm -2 a -I) a uf d en H a nge n zur Baffin Bay und ein solches geringer Akkumulati on « Z5 g cm -2 a -I) in den inneren T e il en d es niirdliche n Ellesmere I sland vorha nd e n ist. Die Ablati o nsr a te n im Somme r zeigen a uf d enselbe n Eiska ppen weit g eringere regiona le Schwa nkungen, mit Ausn a hm e niedrigerer Rat e n la ngs des nordwes tli chen Randes d er Inseln und miiglicherweise auch a uf den H a nge n zur Baffin Bay. D och. bes teht ein e enge re Bez iehung zwisch e n Abla tion und M eeresh iih e, di e unterha lb d e r Firnlinie expon e ntiell en Cha rakter h a t . Aus dem 180-Geha lt des Schn ees ergibt sich, dass aus d er Ba ffin Bay betrachtli che M engen von F eu chtig keit (> 20 % der G esamtm enge) auf di e Hange zur Baffin Bay gela ngen. Als w e it e re, wenn a uch b ei w eitem schwache re F euchtigkeitsquell e ist der Arktische Ozea n anzusehe...

Milne Glacier, Northern Ellesmere Island, N.W.T., Canada: a Surging Glacier?

“…The s mooth appea r ance of the s u r face of Milne Glacier in 1983 suggests that the surge occurred some y ears previously ; in the late 1960s or earl y 1970s. Koerner (1979) ha s s hown the coast of northern Ellesmere Island to have higher a ccumulat i on rates than the higher inland ice caps. However, although the ice shelves and near-coast glaciers have relatively high accumulation rates there is a net loss of ice each year.…”

Characterization of Canadian High Arctic glacier surface albedo from MODIS C6 data, 2001–2016

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Formation of the snow isotopic composition on the Arctic glaciers (case study of Spitsbergen and Severnaya Zemlya)

“…Од на ко бли зость от кры то го мо ря и час тые ад век тив ные ту ма ны на лед ни ках по ляр ных ар хи пе ла гов по зво ля ют пред по ло жить зна чи тель ную роль иных про цес сов кон ден са ции ат мо сфер ной вла ги. На ши изо топ ные ис сле до ва ния [5] по ка за ли, что для грен ланд ско го сне га вклад «ме ст ной» вла ги, ис па рив шей ся с по верх но сти Де ви со ва про ли ва, мо жет дос ти гать 15%; близ кие зна че ния по лу че ны и для лед ни ко во го ку пола Де вон [14].…”