Initial Establishment of Saxicolous Lichens Following Recent Glacial Recession in Sverdrup Pass, Ellesmere Island, Canada

AbstractIn the recently deglaciated zone of a valley glacier in Central Ellesmere Island the mean period of time before the onset of colonization on bare rock surfaces was estimated to be about 80 years. The first species to establish was Xanthoria elegans, followed by Lecanora crenulata and Umbilicaria virginis approximately 20 years later. Summer temperature appeared to be one factor which affected lichen establishment in recently deglaciated bare areas in the High Arctic. Warmer microsites were identified as preferred locations for thallus establishment; these, therefore, constitute ideal sites for studies of thallus initiation under natural conditions. Following the retreat of a glacier from its most advanced Little Ice Age position, 16 species of saxicolous lichens have become established on bare rock debris in the icefree zone, but in nine transects only five species had a constancy of 80% or more. Lichen diversity in this successional photocommunity was comparable to that in a nearby pre-Little Ice Age landscape with more varied substrata.

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Glacier equilibrium line altitude variations during the “Little Ice Age” in the Mediterranean Andes (30◦–37◦ S)

10.5194/cp-2019-37 ◽

2019 ◽

Author(s):

Álvaro González-Reyes ◽

Claudio Bravo ◽

Mathias Vuille ◽

Martin Jacques-Coper ◽

Maisa Rojas ◽

...

Keyword(s):

Little Ice Age ◽

Pearson Correlation ◽

Temporal Changes ◽

Global Climate Models ◽

Ice Age ◽

Equilibrium Line ◽

Equilibrium Line Altitude ◽

Mountainous Regions ◽

The Mean ◽

The Mediterranean

Abstract. The "Little Ice Age" (LIA; 1500–1850 Common Era (CE)), has long been recognized as the last period when mountain glaciers in many regions of the Northern Hemisphere (NH) recorded extensive growth intervals in terms of their ice mass and frontal position. The knowledge about this relevant paleoclimatic interval is vast in mountainous regions such as the Alps and Rocky Mountains in North America. However, in extra-tropical Andean sub-regions such as the Mediterranean Andes of Chile and Argentina (MA; 30º–37º S), the LIA has been poorly documented. Paradoxically, the few climate reconstructions performed in the MA based on lake sediments and tree rings do not show clear evidence of a LIA climate anomaly as observed in the NH. In addition, recent studies have demonstrated temporal differences between mean air temperature variations across the last millennium between both hemispheres. This motivates our hypothesis that the LIA period was not associated with a significant climate perturbation in the MA region. Considering this background, we performed an experiment using daily climatic variables from three Global Climate Models (GCMs) to force a novel glaciological model. In this way, we simulated temporal variations of the glacier equilibrium-line altitude (ELA) to evaluate the glacier response during the period 1500–1848 CE. Overall, each GCM shows temporal changes in annual ELA, with anomalously low elevations during 1640–1670 and 1800–1848 CE. An interval with high ELA values was identified during 1550–1575 CE. The spectral properties of the mean annual ELA in each GCM present significant periodicities between 2–7 years, and also significant decadal to multi-decadal signals. In addition, significant and coherent cycles at interannual to multi-decadal scales were detected between modeled mean annual ELAs and the first EOF1 extracted from Sea Surface Temperature (SST) within the El Niño 3.4 of each GCM. Finally, significant Pearson correlation coefficients were obtained between the mean annual ELA and Pacific SST on interannual to multi-decadal timescales. According to our findings, we propose that Pacific SST variability was the main modulator of temporal changes of the ELA in the MA region of South America during 1500–1848 CE.

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The ENSO teleconnections to the Indian summer monsoon climate through the Last Millennium as simulated by the PMIP3

10.5194/cp-2018-7 ◽

2018 ◽

Cited By ~ 1

Author(s):

Charan Teja Tejavath ◽

Karumuri Ashok ◽

Supriyo Chakraborty ◽

Rengaswamy Ramesh

Keyword(s):

Summer Monsoon ◽

Indian Summer Monsoon ◽

Little Ice Age ◽

Walker Circulation ◽

Summer Monsoon Rainfall ◽

Ice Age ◽

Boreal Summer ◽

Last Millennium ◽

Enso Teleconnections ◽

The Mean

Abstract. Using seven model simulations from the PMIP3, we study the mean summer (June–September) climate and its variability in India during the Last Millennium (LM; CE 850–1849) with emphasis on the Medieval Warm Period (MWP) and Little Ice Age (LIA), after validation of the simulated current day climate and trends. We find that the above (below) LM-mean summer global temperatures during the MWP (LIA) are associated with relatively higher (lower) number of concurrent El Niños as compared to La Niñas. The models simulate higher (lower) Indian summer monsoon rainfall (ISMR) during the MWP (LIA). This is notwithstanding a strong simulated negative correlation between the timeseries of NINO3.4 index and that of the area-averaged ISMR, Interestingly, the percentage of strong El Niños (La Niñas) causing negative (positive) ISMR anomalies is higher in the LIA (MWP), a non-linearity that apparently is important for causing higher ISMR in the MWP. Distribution of simulated boreal summer velocity potential at 850 hPa during MWP in models, in general, shows a zone of anomalous convergence in the central tropical Pacific flanked by two zones of divergence, suggesting a westward shift in the Walker circulation as compared to the simulations for LM as well as and a majority of historical simulations, and current day observed signal. The anomalous divergence centre in the west also extends into the equatorial eastern Indian Ocean, resulting in an anomalous convergence zone over India and therefore excess rainfall during the MWP as compared to the LM; the results are qualitative, given the inter-model spread.

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

Journal of Glaciology ◽

10.1017/s0022143000006043 ◽

1984 ◽

Vol 30 (105) ◽

pp. 251-253 ◽

Cited By ~ 3

Author(s):

Martin O. Jeffries

Keyword(s):

Critical Condition ◽

Maximum Rate ◽

High Arctic ◽

Ellesmere Island ◽

Accumulation Rates ◽

Reservoir Area ◽

Ice Caps ◽

Glacier Terminus ◽

Valley Glacier ◽

Glacier Surges

AbstractDuring the period 1966 to 1983 Milne Glacier advanced 4.25 km at a mean annual rate of 250 m a−1. Since surges commonly occur over a two or three year period the maximum rate of advance could have been greater than 2 km a−1. The glacier terminus has a number of features indicative of past surge behaviour. Of these, at least three looped moraines suggest surges of the main valley glacier and tributary glaciers. As Milne Glacier is a cold glacier, surges may possibly be thermally regulated Accumulation rates on the ice caps of northern Ellesmere Island are low hence a critical condition in the “reservoir area” will be only slowly attained. As a consequence the periodicity of surges in Milne Glacier and other High Arctic glaciers is expected to be high.

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The Claps of Luc-en-Diois (Drôme, SE France) : evaluation of a lake fill volume based on a morphological model

BSGF - Earth Sciences Bulletin ◽

10.2113/175.3.303 ◽

2004 ◽

Vol 175 (3) ◽

pp. 303-312 ◽

Cited By ~ 3

Author(s):

Gilles Brocard

Keyword(s):

Little Ice Age ◽

River Sediment ◽

Sediment Load ◽

Ice Age ◽

Drainage Network ◽

Erosion Rates ◽

Lake Volume ◽

Fill Volume ◽

Morphological Model ◽

The Mean

Abstract The Claps Lake near Luc-en-Diois is a naturally dammed palaeo-lake fed by the Drôme River sediment load during the Little Ice Age (LIA). The present assessment is based on a valley reconstruction using a geomorphic model. It illustrates the potentiality and limits of the geomorphic analysis to accurately predict the buried topography. This method indeed may help to reduce the prospecting work required in classical evaluations of fill volumes of such natural dams. The lake was rapidly filled with sediments, indicating enhanced erosion of the watershed during the LIA. Several studies have attempted to quantify the volume of the lake fill and use it to assess erosion rates during the LIA. Very little is known, however, about the geometry of the buried valley. Estimated lake volumes and erosion rates vary depending on how the buried valley is reconstructed and what correcting factors are used for calculating erosion rates. The present assessment is based on a valley reconstruction using a geomorphic model calibrated by the surrounding drainage network, as well as the introduction of correcting factors that improve the corrections applied in the previous works. The resulting lake volume is 71–81.106 m3, and the mean erosion rate at 0.7-1.2 mm.yr-1, a high value compared to previous estimates. This rate is compared to the results obtained by various methods and over different timescales in the surrounding region.

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Accelerating retreat and high-elevation thinning of glaciers in central Spitsbergen

The Cryosphere ◽

10.5194/tc-10-1317-2016 ◽

2016 ◽

Vol 10 (3) ◽

pp. 1317-1329 ◽

Cited By ~ 26

Author(s):

Jakub Małecki

Keyword(s):

Little Ice Age ◽

High Elevation ◽

Comprehensive Analysis ◽

Ice Age ◽

The Arctic ◽

Digital Elevation ◽

Glacier Changes ◽

The Mean ◽

Geodetic Mass Balance ◽

The 1960S

Abstract. Svalbard is a heavily glacier-covered archipelago in the Arctic. Dickson Land (DL), in the central part of the largest island, Spitsbergen, is relatively arid and, as a result, glaciers there are relatively small and restricted mostly to valleys and cirques. This study presents a comprehensive analysis of glacier changes in DL based on inventories compiled from topographic maps and digital elevation models for the Little Ice Age (LIA) maximum, the 1960s, 1990, and 2009/2011. Total glacier area has decreased by ∼ 38 % since the LIA maximum, and front retreat increased over the study period. Recently, most of the local glaciers have been consistently thinning in all elevation bands, in contrast to larger Svalbard ice masses which remain closer to balance. The mean 1990–2009/2011 geodetic mass balance of glaciers in DL is among the most negative from the Svalbard regional means known from the literature.

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Extension of Glacier de Saint-Sorlin, French Alps, and equilibrium-line altitude during the Little Ice Age

Journal of Glaciology ◽

10.3189/172756502781831548 ◽

2002 ◽

Vol 48 (160) ◽

pp. 118-124 ◽

Cited By ~ 6

Author(s):

Louis Lliboutry

Keyword(s):

Little Ice Age ◽

Meteorological Data ◽

Vertical Gradient ◽

Winter Precipitation ◽

Ice Age ◽

Equilibrium Line ◽

Equilibrium Line Altitude ◽

French Alps ◽

The Mean ◽

Accumulation Area Ratio

AbstractGlacier de Saint-Sorlin, French Alps, left terminal moraines at 1.3, 2.9 and 3.7 km ahead of the present terminus. According to proxy data and to historical maps, these were formed in the 19th, 18th and 17th centuries, respectively. A plateau at 2700–2625 m was then surrounded by ice but never became an accumulation area. This fact shows that the equilibrium-line altitude (ELA) on the glacier never dropped below 2300 m. The following simple models apply sufficiently to yield reliable estimations of past ELA: (1) a uniform and constant vertical gradient of the mass balance, down to the terminus; and (2) a plane bed, with a slope of 8.5° and a uniform width. Then in a steady situation the accumulation–area ratio is 1/2. Compared to the mean for 1956–72, at the onset of the Little Ice Age the balances were higher by 3.75 m ice a−1, and the ELA was 400 m lower. Correlations between 1956–72 balances and meteorological data suggest that during the melting season the 0°C isotherm was about 800 m lower, while the winter precipitation at low altitudes did not change. These correlations may have been different in the past, but an equal lowering of the ELA and of the 0°C isotherm, as assumed by several authors, seems excluded.

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Rapid Wastage of the Hazen Plateau Ice Caps, Northeastern Ellesmere Island, Nunavut, Canada

10.5194/tc-2016-201 ◽

2016 ◽

Author(s):

Mark C. Serreze ◽

Bruce Raup ◽

Carsten Braun ◽

Douglas R. Hardy ◽

Raymond S. Bradley

Keyword(s):

Satellite Data ◽

Little Ice Age ◽

Ellesmere Island ◽

Ice Age ◽

Aerial Photographs ◽

Direct Response ◽

Ice Caps ◽

Warm Summer ◽

Plant Recolonization

Abstract. Two pairs of small stagnant ice bodies on the Hazen Plateau of northeastern Ellesmere Island, the St. Patrick Bay ice caps and the Murray and Simmons ice caps, are rapidly shrinking, and the remnants of the St. Patrick Bay ice caps are likely to disappear entirely within the next five years. Vertical aerial photographs of these Little Ice Age relics taken during August of 1959 show that the larger of the St. Patrick Bay ice caps had an area of 7.48 km2, and the smaller one 2.93 km2. The Murray and Simmons ice caps covered 4.37 km2 and 7.45 km2 respectively. Outlines determined from ASTER satellite data for July 2016 show that, compared to 1959, the larger and the smaller of the St. Patrick Bay ice caps had both been reduced to only 5 % of their former area, with the Murray and Simmons ice caps faring better at 39 % and 25 %, likely reflecting their higher elevation. ASTER imagery in conjunction with past GPS surveys documents a strikingly rapid wastage of the St. Patrick Bay ice caps over the last 15 years. These two ice caps shrank noticeably even between 2014 and 2015, apparently in direct response to the especially warm summer of 2015 over northeastern Ellesmere Island. The well-documented recession patterns of the Hazen Plateau ice caps over the last 55+ years offer an opportunity to examine the processes of plant recolonization of polar landscapes.

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Sedimentary environment, lithostratigraphy and dating of sediment sequences from Arctic lakes Revvatnet and Svartvatnet in Hornsund, Svalbard

Polish Polar Research ◽

10.1515/popore-2016-0005 ◽

2016 ◽

Vol 37 (1) ◽

pp. 23-48 ◽

Cited By ~ 9

Author(s):

Antti E.K. Ojala ◽

Laura Arppe ◽

Tomi P. Luoto ◽

Lukas Wacker ◽

Eija Kurki ◽

...

Keyword(s):

Little Ice Age ◽

Sedimentary Environment ◽

Arctic Lakes ◽

Ice Age ◽

Sedimentary Environments ◽

Northern Basin ◽

Climate And Environmental Change ◽

Dating Methods ◽

Valley Glacier ◽

Paleomagnetic Dating

Abstract The sedimentary environment, sediment characteristics and age-depth models of sediment sequences from Arctic lakes Revvatnet and Svartvatnet, located near the Polish Polar Station in Hornsund, southern Svalbard (77°N), were studied with a view to establishing a basis for paleolimnological climate and environmental reconstructions. The results indicate that catchment-to-lake hydroclimatic processes probably affect the transportation, distribution and accumulation of sediments in different parts of lakes Revvatnet and Svartvatnet. Locations with continuous and essentially stable sedimentary environments were found in both lakes between water depths of 9 and 26 m. We used several different dating techniques, including 137Cs, 210Pb, AMS 14C, and paleomagnetic dating, to provide accurate and secured sediment chronologies. Arecovered sequence from the northern basin of Revvatnet spans more than one thousand years long with laminated stratigraphy in the upper part of the sediment. Based on AMS 14C dates, it is possible to suppose that Revvatnet basin was not occupied by a valley glacier during the Little Ice Age. The dates were supported by 137Cs chronologies, but not confirmed with other independent dating methods that extent beyond the last 50 years. A sedimentary sequence from the northern basin of Svartvatnet provides a potential archive for the study of climate and environmental change for the last ca. 5000 years. Based on the stratigraphy and a Bayesian age-depth model of AMS14C and paleosecular variation (PSV) dates, the recovered sediment sections represent a continuous and stable sedimentation for the latter half of the Holocene.

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