Glaciers are considered to be‘climate-sensitive indicators'and‘solid reservoirs',and their changes significantly impact regional water security.The mass balance(MB)from 2011 to 2020 of the Qiyi Glacier in the northeast Tibetan Plateau is presented based on field observations.The glacier showed a persistent negative balance over 9 years of in-situ observations,with a mean MB of-0.51 m w.e.yr^(-1).The distributed energy-mass balance model was used for glacier MB reconstruction from 1980 to 2020.The daily meteorological data used in the model were from HAR v2 reanalysis data,with automatic weather stations located in the middle and upper parts of the glacier used for deviation correction.The average MB over the past 40 years of the Qiyi Glacier was -0.36 m w.e.yr^(-1)with the mass losses since the beginning of the 21st century,being greater than those in the past.The glacier runoff shows a significant increasing trend,contributing~81% of the downstream river runoff.The albedo disparity indicates that the net shortwave radiation is much higher in the ablation zone than in the accumulation zone,accelerating ablation-area expansion and glacier mass depletion.The MB of the Qiyi Glacier is more sensitive to temperature and incoming shortwave radiation variation than precipitation.The MB presented a non-linear reaction to the temperature and incoming shortwave radiation.Under future climate warming,the Qiyi Glacier will be increasingly likely to deviate from the equilibrium state,thereby exacerbating regional water balance risks.It is found that the mass losses of eastern glaciers are higher than those of western glaciers,indicating significant spatial heterogeneity that may be attributable to the lower altitude and smaller area distribution of the eastern glaciers.
WANG ShengWANG JianwenZHU MeilinYAO TandongPU JianchenWANG Jinfeng
全新世(11.7 ka BP)作为最年轻的地质年代,其气候变化相对晚更新世冰期稳定,但仍存在千百年尺度的气候波动。造成这些气候波动的可能有多种原因,但至今还没有统一的认识。这一时期的气候变化与人类发展有密切的关系,因此其短尺度的气候变化越来越受到学界的关注,已经开展了大量的研究。通过对文献资料分析,综述了全新世千百年尺度的气候突变的原因。全新世早期温度普遍升高主要与太阳活动变化有关,期间冰盖消融与海洋环流作用引起百年尺度的气候事件。全新世中期气温最高,但也发现多次干冷气候事件,主要为冰川活动导致。全新世晚期温度降低,主要是以火山活动导致的气候变冷。其他因素如地球轨道参数、潮汐作用、冰川作用、海洋环流等在全新世各个时期对气候造成影响。
