scholarly journals Surge glaciers during the Little Ice Age in the Pyrenees

2018 ◽  
Vol 44 (1) ◽  
pp. 213 ◽  
Author(s):  
E. Serrano ◽  
R. Martín-Moreno

Historical moraine complexes and erosional features are interesting elements to discern the historical climate changes and evolution, with a complex chronologies that help us to understand the dynamics and glacier evolution during the Little Ice Age (LIA). The existence of landforms as crevasses-squeeze ridges, hummocky moraines and flutes, related to different glacier advances and retreats, allows understanding in a better way the LIA glacier evolution in the Pyrenees. The aim of this work is to show how many LIA moraine complexes have traces of fast flow ice; when the surge dynamic happened; his extent and the environmental meaning. Based on glacier landsystem analysis we have established a work hypothesis on the fast flow or surge dynamic glaciers during the LIA, with geomorphological features, as flutes and push and hummocky moraines, at least in 17 LIA glacier complexes. The analysis of morphosquences by fieldwork, photo interpretation and historical sources in 8 selected LIA moraine complexes have been compared with previous climatic reconstructions creating a hypothesis about the response of the LIA glaciers to the short time changes in temperature and moisture.The glacier cirques with fast flow features are found in the highest mountains with summits above 3000 m., mainly northern oriented (88%) and without a significant lithology. The studied complexes (Central Infierno, Eastern Infierno, Oulettes de Gaube, Monte Perdido, Marboré, La Paúl, Literola and Tempestades) show 4 morphological units: a frontal moraine system (U1); a more voluminous moraine (U2); a little push and hummocky moraines complex linking with flutes (U3); and minor arcs up valley (U4). The U3 belongs to a fast flow stage or surging and by morphostratigraphy we can point out that the surge processes were produced between 1820 and 1840, at the end of the LIA. We related it with a possible climatic response to sudden cooling and the increase of winter precipitation with melt-water availability and quick ice melting during the summer, generating hydrodynamic changes in the small glaciers and quick dynamic response.

2002 ◽  
Vol 48 (160) ◽  
pp. 118-124 ◽  
Author(s):  
Louis Lliboutry

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.


2015 ◽  
Vol 19 (12) ◽  
pp. 4721-4734 ◽  
Author(s):  
O. Böhm ◽  
J. Jacobeit ◽  
R. Glaser ◽  
K.-F. Wetzel

Abstract. This paper describes the flood sensitivity of the Bavarian part of the Alpine Foreland of Germany and addresses different questions concerning climate variability and flood frequencies, from the 14th century until today. The focal point of the paper is the flood frequency of the superordinate spatial unit of the Bavarian Foreland. Based on written historical sources, the flood history of the Alpine Foreland of Germany can be reconstructed back to the 14th century. One major result is the occurrence of "flood-rich" and "flood-poor" episodes in almost cyclical sequences. Flood-rich periods, before the 16th century based on limited available data, were recorded in the periods 1300–1335, 1370–1450, 1470–1525, 1555–1590, 1615–1665, 1730–1780, 1820–1870, and 1910–1955 as well as in a ninth period beginning in 1980. The flood-rich periods are characterized by longer flood duration. Most of the flood-rich and flood-poor periods (in particular the beginning and the end of them) can be connected to changes in natural climate variability. These include changing sunspot numbers (as a measure of solar activity), so-called Little Ice Age type events (LIATEs) as well as changes in the North Atlantic Oscillation (NAO). Climate signals from external forcing factors, which could be used to explain the changing flood frequencies in the Bavarian Alpine Foreland, end in 1930. Relationships within the climate system such as the correlation of flood frequencies with the NAO have changed during the transition from the post Little Ice Age period to the Modern Climate Optimum around 1930. Natural climate variability might have been overlaid by anthropogenic climate change.


2018 ◽  
Vol 64 (243) ◽  
pp. 100-118 ◽  
Author(s):  
CHRIS R. STOKES ◽  
LISS M. ANDREASSEN ◽  
MATTHEW R. CHAMPION ◽  
GEOFFREY D. CORNER

ABSTRACTThe recession of mountain glaciers worldwide is increasing global sea level and, in many regions, human activities will have to adapt to changes in surface hydrology. Thus, it is important to provide up-to-date analyses of glacier change and the factors modulating their response to climate warming. Here we report changes in the extent of >120 glaciers on the Lyngen Peninsula, northern Norway, where glacier runoff is utilised for hydropower and where glacial lake outburst floods have occurred. Glaciers covered at least 114 km2 in 1953 and we compare this inventory with those from 1988, 2001 and a new one from 2014, and previously-dated Little Ice Age (LIA) limits. Results show a steady reduction in area (~0.3% a−1) between their LIA maximum (~1915) and 1988, consistent with increasing summer air temperatures, but recession paused between 1988 and 2001, coinciding with increased winter precipitation. Air temperatures increased 0.5°C per decade from the 1990s and the rate of recession accelerated to ~1% a−1 between 2001 and 2014 when glacier area totalled ~95.7 km2. Small glaciers (<0.05 km2) with low maximum elevations (<1400 m) experienced the largest percentage losses and, if warming continues, several glaciers may disappear within the next two decades.


The Holocene ◽  
2016 ◽  
Vol 27 (2) ◽  
pp. 292-308 ◽  
Author(s):  
Ann V Rowan

Northern Hemisphere cooling between 1400 and 1900 in the Common Era (CE) resulted in the expansion of glaciers during a period known as the ‘Little Ice Age’ (LIA). Early investigation of recent advances of Himalayan glaciers assumed that these events were synchronous with LIA advances identified in Europe, based on the appearance and position of moraines and without numerical age control. However, applications of Quaternary dating techniques such as terrestrial cosmogenic nuclide dating have allowed researchers to determine numerical ages for these young moraines and clarify when glacial maxima occurred. This paper reviews geochronological evidence for the last advance of glaciers in the Himalaya. The 66 ages younger than 2000 years (0–2000 CE) calculated from 138 samples collected from glacial landforms demonstrate that peak moraine building occurred between 1300 and 1600 CE, slightly earlier than the coldest period of Northern Hemisphere air temperatures. The timing of LIA advances varied spatially, likely influenced by variations in topography and meteorology across and along the mountain range. Palaeoclimate proxies indicate cooling air temperatures from 1300 CE leading to a southward shift in the Asian monsoon, increased Westerly winter precipitation and generally wetter conditions across the range around 1400 and 1800 CE. The last advance of glaciers in the Himalaya during a period of variable climate resulted from cold Northern Hemisphere air temperatures and was sustained by increased snowfall as atmospheric circulation reorganised in response to cooling during the LIA.


2017 ◽  
Vol 178 ◽  
pp. 24-36 ◽  
Author(s):  
Jens Fohlmeister ◽  
Birgit Plessen ◽  
Alexey Sergeevich Dudashvili ◽  
Rik Tjallingii ◽  
Christian Wolff ◽  
...  

Author(s):  
W.P. De Lange

The Greenhouse Effect acts to slow the escape of infrared radiation to space, and hence warms the atmosphere. The oceans derive almost all of their thermal energy from the sun, and none from infrared radiation in the atmosphere. The thermal energy stored by the oceans is transported globally and released after a range of different time periods. The release of thermal energy from the oceans modifies the behaviour of atmospheric circulation, and hence varies climate. Based on ocean behaviour, New Zealand can expect weather patterns similar to those from 1890-1922 and another Little Ice Age may develop this century.


2013 ◽  
Vol 6 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Anastasia Gornostayeva ◽  
◽  
Dmitry Demezhko ◽  
◽  
Keyword(s):  

2020 ◽  
Vol 42 (1) ◽  
pp. 4-12
Author(s):  
Valeriy Fedorov ◽  
Denis Frolov

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