Thirty‐year history of glacier melting in the Nepal Himalayas

Fujita, Koji; Thompson, Lonnie G.; Ageta, Yutaka; Yasunari, Tetsuzo; Kajikawa, Yoshiyuki; Sakai, Akiko; Takeuchi, Nozomu

doi:10.1029/2005jd005894

Cited by 29 publications

(23 citation statements)

References 22 publications

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“…2 D-F). Also shown are mass balances reconstructed from analyses of ice cores recovered from the RS and YL glaciers (21,22). The preferable ELA is defined as the ELA in the case that its mass balance profile gives an area-averaged mass balance of zero; i.e., the glacier would retain its present extent if the ELA is located at the preferable altitude.…”

Section: Resultsmentioning

confidence: 99%

Spatially heterogeneous wastage of Himalayan glaciers

Fujita

Nuimura²

2011

Proc. Natl. Acad. Sci. U.S.A.

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242

232

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We describe volumetric changes in three benchmark glaciers in the Nepal Himalayas on which observations have been made since the 1970s. Compared with the global mean of glacier mass balance, the Himalayan glaciers showed rapid wastage in the 1970s-1990s, but similar wastage in the last decade. In the last decade, a glacier in an arid climate showed negative but suppressed mass balance compared with the period 1970s-1990s, whereas two glaciers in a humid climate showed accelerated wastage. A mass balance model with downscaled gridded datasets depicts the fate of the observed glaciers. We also show a spatially heterogeneous distribution of glacier wastage in the Asian highlands, even under the presentday climate warming.climate change | equilibrium line altitude A recent study (1) has highlighted gross inadequacies both in our knowledge of important changes occurring to Himalayan glaciers and in two recent reports that have alternately overestimated (2) and seriously underestimated (3) the pace of shrinkage of Himalayan glaciers without, in either report (2, 3), offering a compelling basis. However, the rate at which Himalayan glaciers are shrinking remains poorly constrained because ground-based measurements are hampered by the high altitude and remoteness of the region. This lack of observational data has given rise to large uncertainties in both observation-based (4-6) and simulation-based (7-9) projections of global sea-level rise. These studies relied on relationships established for well-studied glaciers under a Euro-American climate. However, this approach may be inaccurate because the seasonal cycle of precipitation has a strong effect on the surface albedo and thus on glacier melt in the monsoonal Asian region (10).In addition, much of the debate on the fate of Himalayan glaciers has missed an important consideration of the height and trend of the equilibrium-line altitude (ELA), which divides the glacier into areas of ablation and accumulation (11). The ELA is important because, for example, if the glacier has no accumulation area for a period because the ELA is located above the glacier, the glacier is destined to disappear over time (12). Unfortunately, observations of the mass balance and ELA of Himalayan glaciers have been made only in recent years (13,14).To address these problems, in the present study we update the elevation data for Himalayan benchmark glaciers, providing information for the past decades. We calculate changes in the mass balance and ELA of the three benchmark glaciers using an energy-mass balance model with downscaled gridded climate datasets, in order to describe the state and fate of glaciers. Further calculations are performed to assess the spatial representativeness of the observation-based results.

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Section: Resultsmentioning

confidence: 99%

Spatially heterogeneous wastage of Himalayan glaciers

Fujita

Nuimura²

2011

Proc. Natl. Acad. Sci. U.S.A.

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242

232

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“…It suggests that no event of this magnitude has occurred in the recent decades. Although a 30-year mass balance record of Yala Glacier reconstructed from multiple sources suggests large annual accumulations (solid precipitation > 1200 mm year −1 , greater than +1.4σ ) in 1975, 1976, 1980, and 1981(Fujita et al, 2006, it is unknown whether the precipitation fell as winter snow, which could have led to similar destructive avalanches, or as summer rain, which would not have affected the forest. There is no other record or villagers' narrative suggesting any event to destroy trees in 1980 or earlier.…”

Section: Other In Situ Datamentioning

confidence: 99%

“…and Yala Glacier (5100 m a.s.l.) (Seko, 1987;Fujita et al, 1997;Immerzeel et al, 2014). As the station in Kyangjin malfunctioned in the winter of 2014-2015, we estimate cumulative winter precipitation from observations at Yala Glacier.…”

Section: Automatic Weather Stationsmentioning

confidence: 99%

“…To understand the interaction between meteorology, glaciology, and hydrology, several automatic weather stations and precipitation gauges have been operated in the basin (e.g., Immerzeel et al, 2014;Ragettli et al, 2015; in addition to a long-term meteorological observation at Kyangjin, which was started during the mid-1980s (Fujita et al, 2006) (Fig. 1a).…”

Section: Automatic Weather Stationsmentioning

confidence: 99%

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Anomalous winter-snow-amplified earthquake-induced disaster of the 2015 Langtang avalanche in Nepal

Fujita

Inoue

Izumi

et al. 2017

Nat. Hazards Earth Syst. Sci.

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Abstract. Coseismic avalanches and rockfalls, as well as their simultaneous air blast and muddy flow, which were induced by the 2015 Gorkha earthquake in Nepal, destroyed the village of Langtang. In order to reveal volume and structure of the deposit covering the village, as well as sequence of the multiple events, we conducted an intensive in situ observation in October 2015. Multitemporal digital elevation models created from photographs taken by helicopter and unmanned aerial vehicles reveal that the deposit volumes of the primary and succeeding events were 6.81 ± 1.54 × 10 6 and 0.84 ± 0.92 × 10 6 m 3 , respectively. Visual investigations of the deposit and witness statements of villagers suggest that the primary event was an avalanche composed mostly of snow, while the collapsed glacier ice could not be dominant source for the total mass. Succeeding events were multiple rockfalls which may have been triggered by aftershocks. From the initial deposit volume and the area of the upper catchment, we estimate an average snow depth of 1.82 ± 0.46 m in the source area. This is consistent with anomalously large snow depths (1.28-1.52 m) observed at a neighboring glacier (4800-5100 m a.s.l.), which accumulated over the course of four major snowfall

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“…Glaciers in the Himalaya are retreating at high rates in recent decades [8], exposing the underlying soil and rocks and forming many unstable lakes. Rapid melting of glaciers is changing freshwater resources and their channeling along with the volume of water these channels carry.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Sediment Load of Langtang River in Rasuwa District, Nepal

Chhetri¹,

Kayastha²,

Shrestha³

2016

JWARP

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This paper assesses the sediment load of the glacier fed Langtang River, Nepal from April 2014 to March 2015. Water samples were collected from the centre of the river with a frequency of two samples per each sampling day using the Depth Integration Technique (DIT) on daily basis in the monsoon season, weekly in the pre-and post-monsoon seasons and bi-monthly in the winter season. Suspended sediment concentration (SSC) is calculated from the water samples using filtration followed by oven-drying, and a rating curve is used to calculate daily discharge of the Langtang River. The annual sediment yield is 109,276.75 tons and 37.69, 11.52 and 5.54 tons of sediment is transported per day in the pre-monsoon, post-monsoon and winter seasons, respectively. There is a very high value of 872.86 tons per day in the monsoon season, which contributes the highest sediment load among all of the seasons comprising 83% of the total sediment transport. Diurnal cycle of sediment discharge is clearly seen with higher sediment discharge during the evening than the morning and reaching maximum values of 41.1 kg•s −1 and 61.5 kg•s −1 , respectively. A clock-wise hysteresis loop has been obtained for discharge and sediment discharge where sediment flux is higher in the early monsoon than in the late monsoon for a corresponding discharge.

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Thirty‐year history of glacier melting in the Nepal Himalayas

Cited by 29 publications

References 22 publications

Spatially heterogeneous wastage of Himalayan glaciers

Spatially heterogeneous wastage of Himalayan glaciers

Anomalous winter-snow-amplified earthquake-induced disaster of the 2015 Langtang avalanche in Nepal

Assessment of Sediment Load of Langtang River in Rasuwa District, Nepal

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