Remote-sensing estimate of glacier mass balance over the central Nyainqentanglha Range during 1968 – ∼ 2013

Abstract

Abstract. With high air temperatures and annual precipitation, maritime glaciers in southeastern Tibetgreater on the debris-covered ice than the clean ice. Surface-elevation changes can be influenced by ice 28 cliffs, as well as debris cover, and land-or lake-terminating glaciers and supraglacial lakes. Changes 29 showed spatial and temporal heterogeneity and a substantial correlation with climate warming. 31 Introduction 32The Tibetan Plateau (TP), known as the roof of the world or Third Pole, contains the largest 33 concentration of glaciers and icefield outside the Polar Regions . Meltwater from these 34 feeds the headwaters of many prominent Asian rivers (e.g., the Yellow, Yangtze, Mekong, Salween, 35Brahmaputra, Ganges and Indus) (Immerzeel et al., 2010), and are a key component of the cryospheric 36 system (Li et al., 2008). Glaciers are important climate indicators because their extent and thickness 37 adjust in response to climate change (Oerlemans, 1994; T. Yao et al., 2012). With a warming climate, Ke et al., 2015;Neckel et al., 2014; T. Yao et al., 2012). The 1 relationships between glacier mass balance and climate change, water supply and the risk of 2 glacier-related disasters, are the subject of much current research. 3It is difficult to carry out in-situ observations on the Tibetan Plateau due to its rugged terrain and 4 the great labor and logistical costs. Only 15 glaciers have decades of mass-balance measurements (T. 5Yao et al., 2012). Fortunately, new methods are now available for estimating large-scale glacier mass 6 balance, such as satellite geodesy. By comparing topographic data from more than two points in time, 7glacier volume or height changes can be determined and thence glacier mass balance, after 8 consideration of ice/firn/snow densities (Bolch et al., 2011; Gardelle et al., 2013; Kä ä b et al., 2012; 9 Paul et al., 2015;Pieczonka et al., 2013; Shangguan et al., 2014). 10Glaciers in south-eastern Tibet are reportedly of the temperate (maritime) type and are influenced 11 by the South Asian monsoon (Li et al., 1986; Shi and Liu, 2000). Based on inventories from maps and 12 remote sensing, or field measurements, a substantial reduction in glacier area and length has been et al., 2013). However, the 24 lack of local mass-balance measurements means details on the specific response of these glaciers to 25 climate change were lacking, especially for the western region which is the central Nyainqentanglha 26Range (CNR). Bistatic SAR interferometry is an alternative method to optical photogrammetry and 27 altimetry for analysing topographic change. TanDEM-X was launched in 2010 to join its twin satellite, 28TerraSAR-X, and operates with it in bistatic mode. This mode overcomes the temporal decorrelation 29and atmospheric-delay disturbance associated with conventional repeat-pass interferometry (Jaber et al., TanDEM-X elevation model, glaciers were determined to have experienced strong surface lowering in 32 the CNR, at an average rate of -0.83 ± 0.57 m a -1 from 2000(Neckel et al.,...

Glacier Retreat in Eastern Himalaya Drives Catastrophic Glacier Hazard Chain

“…DEM differences based on the 1968 topographic map (Wu et al., 2018), 1973 Keyhole‐9 (Holzer et al., 2015; Zhou et al., 2018), 2000 SRTM DEM, and 2015 Tandem‐X DEM (Wu et al., 2019) reveal that glaciers in the Eastern Himalayas, including Sedongpu range, experienced a water‐equivalent height loss of 0.46 ± 0.02 m per year (m w.e.a −1 ) and an average thinning of 0.54 ± 0.3 m a −1 between 1968 and 2013, and the rate of loss has been increasing since 2000 (Wu et al., 2018, 2019). Sedongpu Glacier also has retreated 620 m since the 1960s.Continuous shrinkage promoted the icefalls to become thinner or even disappear at the junction between the trunk and tributary glaciers, creating a new free surface at the frontal edge of the hanging glacier (Figures S2a and S2d in Supporting Information ).…”

“…DEM differences based on the 1968 topographic map (Wu et al, 2018), 1973Keyhole-9 (Holzer et al, 2015Zhou et al, 2018), 2000 SRTM DEM, and 2015 Tandem-X DEM (Wu et al, 2019) reveal that glaciers in the Eastern Himalayas, including Sedongpu range, experienced a water-equivalent height loss of 0.46 ± 0.02 m per year (m w.e.a 1 ) and an average thinning of 0.54 ± 0.3 m a 1 between 1968 and 2013, and the rate of loss has been increasing since 2000 (Wu et al, 2018(Wu et al, , 2019. Sedongpu Glacier also has retreated 620 m since the 1960s.…”