Mass balances of Yala and Rikha Samba glaciers, Nepal, from 2000 to 2017

Dorothea Stumm,Sharad Prasad Joshi,Tika Ram Gurung,Gunjan Silwal

doi:10.5194/essd-13-3791-2021

Dorothea Stumm, Sharad Prasad Joshi + Show 2 more

Open Access

https://doi.org/10.5194/essd-13-3791-2021

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Abstract

Abstract. The glacier mass balance is an important variable to describe the climate system and is used for various applications like water resource management or runoff modelling. The direct or glaciological method and the geodetic method are the standard methods to quantify glacier mass changes, and both methods are an integral part of international glacier monitoring strategies. In 2011, we established two glacier mass-balance programmes on Yala and Rikha Samba glaciers in the Nepal Himalaya. Here we present the methods and data of the directly measured annual mass balances for the first six mass-balance years for both glaciers from 2011/2012 to 2016/2017. For Yala Glacier we additionally present the directly measured seasonal mass balance from 2011 to 2017, as well as the mass balance from 2000 to 2012 obtained with the geodetic method. In addition, we analysed glacier length changes for both glaciers. The directly measured average annual mass-balance rates of Yala and Rikha Samba glaciers are −0.80 ± 0.28 and −0.39 ± 0.32 m w.e. a−1, respectively, from 2011 to 2017. The geodetically measured annual mass-balance rate of Yala Glacier based on digital elevation models from 2000 and 2012 is −0.74 ± 0.53 m w.e. The cumulative mass loss for the period 2011 to 2017 for Yala and Rikha Samba glaciers is −4.80 ± 0.69 and −2.34 ± 0.79 m w.e., respectively. The mass loss on Yala Glacier from 2000 to 2012 is −8.92 ± 6.33 m w.e. The winter balance of Yala Glacier is positive, and the summer balance is negative in every investigated year. The summer balance determines the annual balance. Compared to regional mean geodetic mass-balance rates in the Nepalese Himalaya, the mean mass-balance rate of Rikha Samba Glacier is in a similar range, and the mean mass-balance rate of Yala Glacier is more negative because of the small and low-lying accumulation area. During the study period, a change of Yala Glacier's surface topography has been observed with glacier thinning and downwasting. The retreat rates of Rikha Samba Glacier are higher than for Yala Glacier. From 1989 to 2013, Rikha Samba Glacier retreated 431 m (−18.0 m a−1), and from 1974 to 2016 Yala Glacier retreated 346 m (−8.2 m a−1). The data of the annual and seasonal mass balances, point mass balance, geodetic mass balance, and length changes are accessible from the World Glacier Monitoring Service (WGMS, 2021), https://doi.org/10.5904/wgms-fog-2021-05.

Highlights

Glaciers are an essential climate variable (ECV) and contribute to understand and describe the global climate system (IGOS, 2007; Bojinski et al, 2014; Haeberli et al, 2000)
In this article we focus on the mass balance and glacier length changes of Yala and Rikha Samba glaciers measured within the framework of the Hindu Kush Himalayan (HKH) Cryosphere Monitoring Project
The glacier-wide annual mass balances of Yala and Rikha Samba glaciers were negative for all years, except in 2012/2013 when Yala Glacier was almost in balance (−0.01 ± 0.29 m w.e.) and Rikha Samba Glacier had a slightly positive balance (0.12 ± 0.32 m w.e.), reported in Tables 2 and 3 and Figs. 2 and 3

Summary

Introduction

Glaciers are an essential climate variable (ECV) and contribute to understand and describe the global climate system (IGOS, 2007; Bojinski et al, 2014; Haeberli et al, 2000). The glacier mass balance is one of the seven headline indicators for global climate monitoring (Trewin et al, 2021) and one of the products of the ECV glacier, besides area and glacier thickness changes (GCOS, 2016). Mass-balance monitoring with the glaciological method is an integral part of international glacier monitoring strategies (Gärtner-Roer et al, 2019; Haeberli et al, 2007; Trewin et al, 2021). GTN-G is the framework for the internationally coordinated monitoring of the ECV glacier and in support of the United Nations Framework Convention on Climate Change (UNFCCC)

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