Reconstructing glacier retreat since the Little Ice Age in SE Tibet by glacier mapping and equilibrium line altitude calculation

Geomorphology ◽  
2014 ◽  
Vol 214 ◽  
pp. 22-39 ◽  
Author(s):  
David Loibl ◽  
Frank Lehmkuhl ◽  
Jussi Grießinger
2019 ◽  
Author(s):  
Álvaro González-Reyes ◽  
Claudio Bravo ◽  
Mathias Vuille ◽  
Martin Jacques-Coper ◽  
Maisa Rojas ◽  
...  

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.


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.


2008 ◽  
Vol 48 ◽  
pp. 93-99 ◽  
Author(s):  
Rijan Bhakta Kayastha ◽  
Sandy P. Harrison

AbstractChanges of the equilibrium-line altitude (ELA) since the end of the Little Ice Age (LIA) in eastern Nepal have been studied using glacier inventory data. The toe-to-headwall altitude ratios (THARs) for individual glaciers were calculated for 1992, and used to estimate the ELA in 1959 and at the end of the LIA. THAR for debris-free glaciers is found to be smaller than for debris-covered glaciers. The ELAs for debris-covered glaciers are higher than those for debris-free glaciers in eastern Nepal. There is considerable variation in the reconstructed change in ELA (ΔELA) between glaciers within specific regions and between regions. This is not related to climate gradients, but results from differences in glacier aspect: southeast- and south-facing glaciers show larger ΔELAs in eastern Nepal than north- or west-facing glaciers. The data suggest that the rate of ELA rise may have accelerated in the last few decades. The limited number of climate records from Nepal, and analyses using a simple ELA–climate model, suggest that the higher rate of the ΔELA between 1959 and 1992 is a result of increased warming that occurred after the 1970s at higher altitudes in Nepal.


1999 ◽  
Vol 28 ◽  
pp. 141-145 ◽  
Author(s):  
Rudolf Sailer ◽  
Hanns Kerschner

AbstractThree cirques in the Ferwall group, western Tyrol, Austria, which are characterized by distinct Late-glacial moraines and rock glaciers, are discussed. The morphology of the moraines and the depression of the equilibrium-line altitude suggest they were deposited during the Egesen Stadial (Younger Dryas), which can be subdivided into three substages. Rock-glacier formation was initialized during or after the Egesen II substage. They became inactive at the Pleistocene—Holocene transition. ELA values are 290–320 m lower than the Little Ice Age ELA during the Egesen I substage, 190–230 m lower during the Egesen II substage and 120 —160 m lower during the Egesen III substage. The lowering of the rock-glacier belt (discontinuous permafrost) during and after the Egesen II substage is about 400 m, indicating a mean annual air-temperature depression in the order of 3 K. During the Egesen I (earlyYounger Dryas), the climate seems to have been rather cold and wet with precipitation similar to present-day values. During later phases (Egesen II and III), the climate remained cold and became increasingly drier. The rise of the ELA during the Egesen I—III substages seems to have been mainly caused by a decrease in precipitation.


2021 ◽  
Author(s):  
Bethan Davies ◽  
Jacob Bendle ◽  
Robert McNabb ◽  
Jonathan Carrivick ◽  
Christopher McNeil ◽  
...  

<p>The Alaskan region (comprising glaciers in Alaska, British Columbia and Yukon) contains the third largest ice volume outside of the Greenland and Antarctic ice sheets, and contributes more to global sea level rise than any other glacierised region defined by the Randolph Glacier Inventory. However, ice loss in this area is not linear, but in part controlled by glacier hypsometry as valley and outlet glaciers are at risk of becoming detached from their accumulation areas during thinning. Plateau icefields, such as Juneau Icefield in Alaska, are very sensitive to changes in Equilibrium Line Altitude (ELA) as this can result in rapidly shrinking accumulation areas. Here, we present detailed geomorphological mapping around Juneau Icefield and use this data to reconstruct the icefield during the “Little Ice Age”. We use topographic maps, archival aerial photographs, high-resolution satellite imagery and digital elevation models to map glacier lake and glacier area and volume change from the Little Ice Age to the present day (1770, 1948, 1979, 1990, 2005, 2015 and 2019 AD). Structural glaciological mapping (1979 and 2019) highlights structural and topographic controls on non-linear glacier recession.  Our data shows pronounced glacier thinning and recession in response to widespread detachment of outlet glaciers from their plateau accumulation areas. Glacier detachments became common after 2005, and occurred with increasing frequency since then. Total summed rates of area change increased eightfold from 1770-1948 (-6.14 km<sup>2</sup> a<sup>-1</sup>) to 2015-2019 (-45.23 km<sup>2</sup> a<sup>-1</sup>). Total rates of recession were consistent from 1770 to 1990 AD, and grew increasingly rapid after 2005, in line with regional warming.</p>


2003 ◽  
Vol 49 (164) ◽  
pp. 117-124 ◽  
Author(s):  
Liu Shiyin ◽  
Sun Wenxin ◽  
Shen Yongping ◽  
Li Gang

AbstractBased on aerial photographs, topographical maps and the Landsat-5 image data, we have analyzed fluctuations of glaciers in the western Qilian Shan, north-west China, from the Little Ice Age (LIA) to 1990. The areas and volumes of glaciers in the whole considered region decreased 15% and 18%, respectively, from the LIA maximum to 1956. This trend of glacier shrinkage continued and accelerated between 1956 and 1990. These latest decreases in area and volume were about 10% in 34 years. The recent shrinkage may be due either to a combination of higher temperatures and lower precipitation during the period 1956–66, or to continuous warming in the high glacierized mountains from 1956 to 1990. As a consequence, glacier runoff from ice wastage between 1956 and 1990 has increased river runoff by 6.2 km3 in the four river basins under consideration. Besides, the equilibrium-line altitude (ELA) rise estimated from the mean terminus retreat of small glaciers <1 km long is 46 m, which corresponds to a 0.3°C increase of mean temperatures in warm seasons from the LIA to the 1950s.


The Holocene ◽  
2017 ◽  
Vol 27 (9) ◽  
pp. 1350-1358 ◽  
Author(s):  
Andrew P Moran ◽  
Susan Ivy Ochs ◽  
Marcus Christl ◽  
Hanns Kerschner

A two-phased moraine system in the high Alpine valley of Lisenser Längental in the Stubai Alps of western Austria is located in an intermediate morphostratigraphic position constrained by ‘Egesen Stadial’ (Younger Dryas) moraines down valley and ‘Little Ice Age’ (‘LIA’) positions (modern times) up valley. The equilibrium line altitude (ELA) was about 50 m lower than during the ‘LIA’ when applying an accumulation area ratio of 0.67. Exposure dating of boulders with 10Be yields a mean age of 3750 ± 330 years for the more extensive outer moraine system and a single age of 3140 ± 280 years for the inner one. The ages correspond well to the ‘Loebben oscillation’, a sequence of multi-decadal to multi-centennial cooling phases at the onset of the late-Holocene, also recognized in other Alpine records. The climatic downturn was severe enough to cause small to medium-sized Alpine glaciers in the central Alps to advance significantly beyond their ‘LIA’ extent, but too short to trigger a similar reaction with large glaciers.


2020 ◽  
Author(s):  
Jesús Alcalá Reygosa ◽  
Néstor Campos ◽  
Melaine Le Roy ◽  
Bijeesh Kozhikkodan Veettil ◽  
Adam Emmer

&lt;p&gt;The Little Ice Age (LIA) occurred between CE 1250 and 1850 and is considered a period of moderate cold conditions, especially recorded in the northern hemisphere. Numerous recent studies provide robust evidence of glacier advances worldwide during the LIA and a dramatic retreat since then. These studies combined investigation of moraine records, paintings, topographical and glaciological measurements as well as multitemporal aerial and terrestrial photographs and satellite images. For instance, post-LIA glaciers retreat amounts ~60 % in the Alps (Paul et al., 2020), ~88 % in the Pyrenees (Rico et al., 2016) and 89 % in the Bolivian Andes (Ram&amp;#237;rez et al., 2001). However, there is scarce knowledge in Mexico about the glacier changes since the LIA. The reconstructions are limited to the Iztacc&amp;#237;hualt volcano where Schneider et al. (2008) established a glacier retreat of 95 %.&lt;/p&gt;&lt;p&gt;Here, we reconstruct the glacier evolution since the LIA to CE 2015 of the Mexican highest ice-capped volcano: Pico de Orizaba (19&amp;#176; 01&amp;#180; N, 97&amp;#176; 16&amp;#180;W, 5,675 m a.s.l.). Due to Pico de Orizaba is in the outer Tropic, the most plausible scenario is a glacier evolution similar to the Bolivian Andes and especially to the Iztacc&amp;#237;hualt volcano. To carry out this research, we mapped the glacier area during the LIA, based on moraine record, and the area during 1945, 1958, 1971, 1988, 1994, 2003 and 2015 using a previous map elaborated by Palacios and V&amp;#225;zquez-Selem (1996), aerial orthophotographs and satellite images. The geographical mapping and the calculus of area, minimum altitude and volume of the glacier were generated with the software ArcGIS 10.2.2. The results show that glacier area retreated 92% between the LIA (8.8 km&lt;sup&gt;2&lt;/sup&gt;) and 2015 (0.67 km&lt;sup&gt;2&lt;/sup&gt;), being a drastic glacier loss in agreement with the Bolivian Andes and Iztacc&amp;#237;hualt. Therefore, mexican glaciers have experienced the major shrunk since LIA that implies a highly sensitive reaction to global warming.&lt;/p&gt;&lt;p&gt;This research was supported by the Project UNAM-DGAPA-PAPIIT grant IA105318.&lt;/p&gt;&lt;p&gt;References&lt;/p&gt;&lt;p&gt;Palacios, D., V&amp;#225;zquez-Selem, L. 1996. Geomorphic effects of the retreat of Jamapa glacier, Pico de Orizaba volcano (Mexico). Geografiska Annaler, Series A, Physical Geography 78, 19-34.&lt;/p&gt;&lt;p&gt;Paul F., Rastner P., Azzoni R.S., Diolaiuti G., Fugazza D., Le Bris R., Nemec J., Rabatel A., Ramusovic M., Schwaizer G., and Smiraglia C. 2020. Glacier shrinkage in the Alps continues unabated as revealed by a new glacier inventory from Sentinel-2 https://doi.org/10.5194/essd-2019-213.&lt;/p&gt;&lt;p&gt;Ram&amp;#237;rez, E., Francou, B., Ribstein, P., Descloitres, M., Gu&amp;#233;rin, R., Mendoza, J., Gallaire, R., Pouyaud, B., Jordan, E. 2001. Small glaciers disappearing in the tropical Andes: a case study in Bolivia: Glaciar Chacaltaya (16&amp;#176; S). Journal of Glaciology 47 (157), 187-194.&lt;/p&gt;&lt;p&gt;Rico I., Izagirre E., Serrano E., L&amp;#243;pez-Moreno J.I., 2016. Current glacier area in the Pyrenees&amp;#160;: an updated assessment 2016. Pirineos 172, doi: http://dx.doi.org/10.3989/Pirineos.2017.172004.&lt;/p&gt;&lt;p&gt;Schneider, D., Delgado-Granados, H., Huggel, C., K&amp;#228;&amp;#228;b, A. 2008. Assessing lahars from ice-capped volcanoes using ASTER satellite data, the SRTM DTM and two different flow models: case study on Iztacc&amp;#237;huatl (Central Mexico). Natural Hazards and Earth System Sciences 8, 559-571.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;


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