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3 results on '"Surface thinning"'

1. Spatial pattern of the debris-cover effect and its role in the Hindu Kush-Pamir-Karakoram-Himalaya glaciers.

Author

Zhang, Yong, Gu, Ju, Liu, Shiyin, Wang, Xin, Jiang, Zongli, Wei, Junfeng, and Zheng, Yajie

Subjects
*GLACIERS, *WATER supply, *GLACIAL melting, *WATER shortages, *HINDUS, *CLIMATE change
Abstract

• Supraglacial debris covers 14.3% of the Hindu Kush-Pamir-Karakoram-Himalaya (HPKH) glaciers. • Spatial patterns of acceleration and insulation effects of debris cover are identified for the first time in the HPKH region. • The insulation effect of debris cover reduces regional mass loss of 0.44 m w.e. yr−1, retarding regional water shortage risk. • Acceleration effect of debris cover is not dominant cause of the debris-cover anomaly. Supraglacial debris is widespread on the Hindu Kush-Pamir-Karakoram-Himalaya (HPKH) glaciers, which influences ice melt rates and glacier response to climate change, with important consequences for regional water resources. Supraglacial debris has shown an expanding trend with glacier shrinkage and mass loss, but knowledge about regional spatial patterns of debris cover and associated impacts on HPKH glaciers is still incomplete, which markedly affects the assessment accuracy of regional debris-covered glacier status and hydrological impacts. Here, we address these issues based on ASTER imagery, glacier inventory, and a physically-based ice melt model. We find that about 14.3 % of the regional glacier area is covered by supraglacial debris, and its thickness decreases gradually from northwest to southeast of the region overall. Except for the glaciers of western Himalaya and Karakoram, where the acceleration effect of debris cover is dominant, the insulation effect of debris cover on the glaciers of Pamir, Hindu-Kush, central and eastern Himalaya is particularly significant. The heterogeneous distribution of debris thickness and the resulting melt hotspots (ice cliffs and supraglacial ponds) enhance debris-covered surface thinning in the HPKH region, but it is not the dominant cause of surface thinning. Overall, the net effect of considering spatially distributed debris thickness can reduce total mass loss of debris-covered glaciers by 0.44 ± 0.04 m water equivalent (w. e.) yr−1. As a result, the presence of debris cover retards accelerated glacier melting caused by current climate warming, with important implications for slowing down regional water shortage and ecological environment risk in the HPKH region. Our findings highlight the importance of including the debris-cover effect in regional glacier models for assessing future glacier change and associated hydrological impacts in the HPKH region. [ABSTRACT FROM AUTHOR]

Published
2022
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2. Thinning of the Monte Perdido Glacier in the Spanish Pyrenees since 1981

Author

Esteban Alonso-González, Juan I. López-Moreno, Jesús Revuelto, Enrique Serrano, José María García-Ruiz, Sergio M. Vicente-Serrano, Alfredo Serreta, Javier Chueca-Cía, Cesar Azorin-Molina, Asunción Julián, and Ibai Rico

Subjects
010504 meteorology & atmospheric sciences, 010502 geochemistry & geophysics, 01 natural sciences, Glaciares, Precipitation, Global change, lcsh:Environmental sciences, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, lcsh:GE1-350, geography, Surface thinning, geography.geographical_feature_category, Thinning, Bedrock, lcsh:QE1-996.5, Accumulation zone, Elevation, Disminución de superficies, Glacier, Albedo, Debris, lcsh:Geology, Climatology, Physical geography, Cambio global, Geomorfología - España - Monte Perdido, Glaciers, Geology
Abstract

Producción Científica, This paper analyzes the evolution of the Monte Perdido Glacier, the third largest glacier in the Pyrenees, from 1981 to the present. We assessed the evolution of the glacier's surface area by analysis of aerial photographs from 1981, 1999, and 2006, and changes in ice volume by geodetic methods with digital elevation models (DEMs) generated from topographic maps (1981 and 1999), airborne lidar (2010) and terrestrial laser scanning (TLS, 2011, 2012, 2013, and 2014) data. We interpreted the changes in the glacier based on climate data from nearby meteorological stations. The results indicate that the degradation of this glacier accelerated after 1999. The rate of ice surface loss was almost three times greater during 1999–2006 than during earlier periods. Moreover, the rate of glacier thinning was 1.85 times faster during 1999–2010 (rate of surface elevation change = −8.98 ± 1.80 m, glacier-wide mass balance = −0.73 ± 0.14 m w.e. yr−1) than during 1981–1999 (rate of surface elevation change = −8.35 ± 2.12 m, glacier-wide mass balance = −0.42 ± 0.10 m w.e. yr−1). From 2011 to 2014, ice thinning continued at a slower rate (rate of surface elevation change = −1.93 ± 0.4 m yr−1, glacier-wide mass balance = −0.58 ± 0.36 m w.e. yr−1). This deceleration in ice thinning compared to the previous 17 years can be attributed, at least in part, to two consecutive anomalously wet winters and cool summers (2012–2013 and 2013–2014), counteracted to some degree by the intense thinning that occurred during the dry and warm 2011–2012 period. However, local climatic changes observed during the study period do not seem sufficient to explain the acceleration of ice thinning of this glacier, because precipitation and air temperature did not exhibit statistically significant trends during the study period. Rather, the accelerated degradation of this glacier in recent years can be explained by a strong disequilibrium between the glacier and the current climate, and likely by other factors affecting the energy balance (e.g., increased albedo in spring) and feedback mechanisms (e.g., heat emitted from recently exposed bedrock and debris covered areas)., Ministerio de Economía, Industria y Competitividad - IBERNIEVE (project CGL2014-52599-P), Ministerio de Agricultura y Pesca, Alimentación y Medio Ambiente (project 844/2013)

Published
2016

3. Thinning of the Monte Perdido Glacier in the Spanish Pyrenees since 1981

Author

López Moreno, Juan Ignacio and López Moreno, Juan Ignacio

Abstract

Producción Científica, This paper analyzes the evolution of the Monte Perdido Glacier, the third largest glacier in the Pyrenees, from 1981 to the present. We assessed the evolution of the glacier's surface area by analysis of aerial photographs from 1981, 1999, and 2006, and changes in ice volume by geodetic methods with digital elevation models (DEMs) generated from topographic maps (1981 and 1999), airborne lidar (2010) and terrestrial laser scanning (TLS, 2011, 2012, 2013, and 2014) data. We interpreted the changes in the glacier based on climate data from nearby meteorological stations. The results indicate that the degradation of this glacier accelerated after 1999. The rate of ice surface loss was almost three times greater during 1999–2006 than during earlier periods. Moreover, the rate of glacier thinning was 1.85 times faster during 1999–2010 (rate of surface elevation change = −8.98 ± 1.80 m, glacier-wide mass balance = −0.73 ± 0.14 m w.e. yr−1) than during 1981–1999 (rate of surface elevation change = −8.35 ± 2.12 m, glacier-wide mass balance = −0.42 ± 0.10 m w.e. yr−1). From 2011 to 2014, ice thinning continued at a slower rate (rate of surface elevation change = −1.93 ± 0.4 m yr−1, glacier-wide mass balance = −0.58 ± 0.36 m w.e. yr−1). This deceleration in ice thinning compared to the previous 17 years can be attributed, at least in part, to two consecutive anomalously wet winters and cool summers (2012–2013 and 2013–2014), counteracted to some degree by the intense thinning that occurred during the dry and warm 2011–2012 period. However, local climatic changes observed during the study period do not seem sufficient to explain the acceleration of ice thinning of this glacier, because precipitation and air temperature did not exhibit statistically significant trends during the study period. Rather, the accelerated degradation of this glacier in recent years can be explained by a strong disequilibrium between the glacier and the current climate, and likely by other facto, Ministerio de Economía, Industria y Competitividad - IBERNIEVE (project CGL2014-52599-P), Ministerio de Agricultura y Pesca, Alimentación y Medio Ambiente (project 844/2013)

Published
2016

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