Last Glacial Maximum glacier modelling in the Quemuqu Valley, southern Tibetan Plateau, and its climatic implications

Abstract

A well‐preserved Last Glacial Maximum (LGM) moraine set in the Quemuqu Valley on the eastern slope of the Qiongmu Gangri Peak offers great potential for reconstructing LGM glacier extent and examining LGM climate in the region. This study employed a coupled and physics‐based mass balance and ice‐flow model to investigate glacier sensitivities to climate in the valley. Based on the sensitivity tests and the well‐preserved LGM moraines, the study also reconstructed the LGM glacier extent in the valley and assessed the magnitude of cooling for the LGM period. Model results suggest that the Quemuqu Valley sustained an ice volume of 6.80±0.16 km3 in the LGM period. Temperature depression of 3.1–4.3 °C, combined with 30–70% modern precipitation, is likely to have supported the LGM glacier extent in the valley. The temperature inference for the LGM period is comparable with other independent palaeoclimate evidence in the region. However, there is a large difference in the reconstructed glacier volume (ice thickness) between previous research and the current study. The glacier model used here directly calculates the ice thickness and needs relatively less field evidence to constrain the model simulations. It is therefore advocated to use such a model to reconstruct past glaciers and their corresponding climates for other valleys of the Tibetan Plateau.

Three-stage Linear Model Simulation of Midui Glacier since Little Ice Age (LIA)

“…The summer temperature was the dominant control on annual mass balance ultimately affecting glacier fluctuation in most of the glacial regions [48,49]. The previous approaches of glacier modelling in the TP also suggested that steady warming was more adequete factor on evolution of glaciers during various time periods [22,23]. The reason might be that the temperature is spatially more stable or homogeneous, less affected by topographic variations as compared to precipitation [50].…”

“…The simple linear models provided dependency of numerical solutions on glacier geometry, and could be used to estimate the response of glacier across a wider range of parameter uncertainty [21]. Various dynamic and linear glacier models have been used to simulate the evolution of glaciers and prediction of glacier response to changing climate, which further highlights the impact of temperature and precipitation on the Tibetan Plateau [22,23].…”

Late quaternary glacial history of the La Ji Shan: Implications for the LGM on the northeastern Tibetan Plateau

“…Based on previous studies, the A, B, and f values used in this study are 1.0 × 10 −7 a −1 kPa −3 , 1.5 × 10 −3 m a −1 kPa −2 , and .5, respectively (Plummer and Phillips, 2003;Refsnider et al, 2008). The DDF value is the main model parameter that controls the uncertainties on the model results owing to its larger variations compared with T s , on the Tibetan Plateau (Xu et al, 2020b). To test the effects of the DDF values on our model results, different DDF values (6-9 mm d −1 °C−1 ) were used to test the model sensitivity to changes in DDF.…”

“…Davide Tiranti, Agenzia Regionale per la Protezione Ambientale del Piemonte (Arpa Piemonte), Italy and Glasser, 2015; Xu et al, 2016;Xu et al, 2017a;Xu et al, 2017b;Xu and Yi, 2017;Eaves et al, 2019;Xu et al, 2020a;Xu et al, 2020b;Cui et al, 2020;Doughty et al, 2021).…”

“…The coupled mass balance and ice flow model is designed to simulate glacier dynamics and thermodynamic processes by running on a digital elevation model (DEM) of the bedrock (Plummer and Phillips, 2003;Refsnider et al, 2008). Detailed information regarding the model was described in Xu et al (2013Xu et al ( , 2016Xu et al ( , 2020b. In this paper, the model input data sets and parameters are briefly described.…”