Proglacial icings as indicators of glacier thermal regime : ice thickness changes and icing occurrence in Svalbard

Proglacial icings (also known as naled or aufeis) are frequently observed in the forefields of polar glaciers. Their formation has been ascribed to the refreezing of upwelling groundwater that has originated from subglacial melt, and thus the presence of icings has been used as evidence of polythermal glacier regime. We provide an updated analysis of icing occurrence in Svalbard and test the utility of icings as an indicator of thermal regime by comparing icing presence with: (1) mean glacier thickness, as a proxy for present thermal regime; and (2) evidence of past surge activity, which is an indicator of past thermal regime. A total of 279 icings were identified from TopoSvalbard imagery covering the period 2008-2012, of which 143 corresponded to icings identified by Bukowska-Jania and Szafraniec (2005) from aerial photographs from 1990. Only 46% of icings observed in 2008-2012 were found to occur at glaciers with thicknesses consistent with a polythermal regime, meaning a large proportion were associated with glaciers predicted to be of a cold or transitional thermal regime. As a result, icing presence alone may be an unsuitable indicator of glacier regime. We further found that, of the 279 glaciers with icings, 63% of cold-based glaciers and 64% of transitional glaciers were associated with evidence of surge activity. We therefore suggest that proglacial icing formation in Svalbard may reflect historical (rather than present) thermal regime, and that icings possibly originate from groundwater effusion from subglacial taliks that persist for decades following glacier thinning and associated regime change

Equifinality and preservation potential of complex eskers

Eskers are useful for reconstructing meltwater drainage systems of glaciers and ice sheets. However, our process understanding of eskers suffers from a disconnect between sporadic detailed morpho‐sedimentary investigations of abundant large‐scale ancient esker systems, and a small number of modern analogues where esker formation has been observed. This paper presents the results of detailed field and high‐resolution remote sensing studies into two esker systems that have recently emerged at Hørbyebreen, Svalbard, and one at Breiðamerkurjökull, Iceland. Despite the different glaciological settings (polythermal valley glacier vs. active temperate piedmont lobe), in all cases a distinctive planform morphology has developed, where ridges are orientated in two dominant directions corresponding to the direction of ice flow and the shape of the ice margin. These two orientations in combination form a cross‐cutting and locally rectilinear pattern. One set of ridges at Hørbyebreen is a hybrid of eskers and geometric ridges formed during a surge and/or jökulhlaup event. The other sets of ridges are eskers formed time‐transgressively at a retreating ice margin. The similar morphology of esker complexes formed in different ways on both glacier forelands implies equifinality, meaning that care should be taken when interpreting Quaternary esker patterns. The eskers at Hørbyebreen contain substantial ice‐cores with a high ice:sediment ratio, suggesting that they would be unlikely to survive after ice melt. The Breiðamerkurjökull eskers emerged from terrain characterized by buried ice that has melted out. Our observations lead us to conclude that eskers may reflect a wide range of processes at dynamic ice margins, including significant paraglacial adjustments. This work, as well as previous studies, confirms that constraints on esker morphology include: topographic setting (e.g. confined valley or broad plain); sediment and meltwater availability (including surges and jökulhlaups); position of formation (supraglacial, englacial or subglacial); and ice‐marginal dynamics such as channel abandonment, the formation of outwash heads or the burial and/or exhumation of dead ice

Meteorological conditions in Petunia Bay (central Spitsbergen) during summer seasons 2000 and 2001

In the years 2000 and 2001 observations of meteorological conditions were carried by expeditions of Adam Mickiewicz University in the vicinity of Petunia Bay (Billefjorden, Central Spitsbergen). The meteorological station Skottehytta (78°42,98?N and 16°36,68?E) is located about 50 m of the sea-side, on a rised marine terrace, 5 m a.s.l. The presented database includes the comparison of 30 days period between 10th July and 8th August in both years and a set of values of the whole expedition in 2001 (7th July - 17th September). Observations carried by an automatic station and in five terms a day cycle covered: atmospheric pressure, air temperature, relative humidity, visibility, degree of cloudiness, precipitation, wind speed and direction. The analysis, performed mainly on daily means, partly on maximum values of selected elements and in the case of precipitation on daily totals, showed a confirmation of general characteristics presented in other papers concerning the area under study. In this a slight rise of air temperatures over a multiyear average, low level of precipitation but an increase in the frequency of heavy precipitation events. Wind conditions of the inner-fjord area are strictly connected with local orography, causing frequent foehn-effects. Processes which are described on the example of Petunia Bay can also illustrate the characteristics of global climatic changes, which are clearly visible in high latitudes of Northern Hemisphere

Poznań polar meteorological and climatological research

W artykule przedstawiono historię badań meteorologicznych i klimatycznych prowadzonych przez pracowników Uniwersytetu im. Adama Mickiewicza w Poznaniu na dwóch skrajnych obszarach polarnych, to jest Arktyce Wysokiej oraz Antarktyce Morskiej. Badania te głównie obejmowały okresy letnie w Arktyce oraz 4-letnią serię obserwacyjną w Antarktyce. Przeprowadzone badania stanowią podstawę do opisu uwarunkowań klimatycznych współczesnych procesów deglacjacji na skutek globalnych anomalii klimatycznych.His paper presents the history of meteorological investigation and climatic studiem conducted by employees of the Adam Mickiewicz University In Poznań on two extreme polar regions, ie. The High Arctic and the Maritime Antarctic. These observation mainly included summer periods in the Arctic and 4-year series of observation in Antarctica. They studied climatic conditions of present-day deglaciation processes due to global climate anomalies

Comparison of the course od air temperature in Petuniabukta and Svalbard-Lufthavn (Isfjord, Spitsbergen) in the years 2001-2003)

W pracy porównano dobowe wartości temperatury powietrza mierzonej w okresie 7 VII 2001 – 13 VIII 2003 roku w Petuniabukta położonej w głębi Billefjorden i Svalbard-Lufthavn leżącym na południowym brzegu Isfjordu. Średnia miesięczna temperatura latem (VI–VIII) jest w Petuniabukta o 1 deg wyższa, a zimą (XI–IV) o około 3 deg niższa niż w Svalbard-Lufthavn. W sezonach zimowych średnie dobowe wartości temperatury w Petuniabukta są przeciętnie o 2–4 deg niższe niż w Svalbard-Lufthavn, a latem o 1–2 deg wyższe.This work presents values of daily air temperature measured in the period 7th July 2001 – 13th August 2003 in Petuniabukta located inside Billefjorden and in Svalbard-Lufthavn located at the southern coast of Isfjord. Mean monthly temperature in summer (June-August) in Petuniabukta was found to be 1deg higher and in winter (November – April) about 3deg lower than at Svalbard-Lufthavn (Tab.1). During winter seasons mean daily temperatures in Petuniabukta are about 2–4deg lower than at Svalbard-Lufthavn and in summer 1–2deg higher (Fig.6). The transition periods are characterized by great differences in temperatures. At the beginning of autumn, in September, thermal conditions in NE (Skottehytta) and S (Svalbard-Lufthavn) part of Isfjord are similar, later, the shorter the day is, the colder the inside of the Billefjorden becomes. In October the temperature at Skottehytta was already 1deg lower than at Svalbard-Lufthavn. In May 2002 it was 2.1deg warmer at Svalbard-Lufthavn and in 2003 it was 2.6deg warmer at Petuniabukta. Taking into consideration similar ice conditions observed during these two years in May both in the vicinity of the station and in the foreshore of the Isfjord, the observed differences in thermal conditions must be attributed to changes in cloudiness and to advection factor. In individual months significant differences in temperatures are noted at both stations. The greatest differences in temperatures between stations are observed from January to April (Tab.3, Fig.3 and 4). During the analyzed period the strongest correlations were noted in the months of the latter part of the year, i.e. from September to December (r >0.9) and the weakest were found in June (Tab.2, Fig.7). 13