5.1 Dominant control of sediment fluxes: temperature or
precipitation?
The seasonal variations in discharge and sediment load are jointly
controlled by air temperature and summer rainfall (Figure 7). At the
Ming Yong Glacier, fractures in the ice form crevasses, providing
pathways for surface water to penetrate the glacier (Miles et al.,
2020). In summer, elevated air temperatures increase the surface melting
and generate snow-glacier meltwater (Lau et al., 2010). The meltwater
can flow from the surface to base through glacier conduits (Eyles,
2006), leading to higher meltwater flow velocity and capacity. As a
result, there is an increase in meltwater erosion and sediment export
(Delaney & Adhikari, 2020; Mao & Carrillo, 2017). Concurrently, the
intense rainfall in July from the Indian monsoon increases the rate of
exposed slope erosion and can trigger landslides and rock avalanches,
leading to the observed high sediment loads (Table S1) (Kirschbaum et
al., 2020; Rosser, 2010). In other words, the discharge and suspended
sediment load peaks observed in July can be explained by higher sediment
accessibility, mobilization, and transport from the monsoon rainfall
Conversely in winter, reduced snow/glacier melting and the decreased
rainfall causes the deformation of the glacial conduits. Furthermore,
accumulated snow shield the underlying crevasses (Carrillo & Mao, 2020;
Gatesman, 2017), thereby weakening erosion and reducing the transport of
sediments into the proglacial stream.(Table S1).