A 1000 year climate ice-core record from the Guliya ice cap, China: its relationship to global climate variability

Abstract

In 1992, an American-Chinese expedition successfully recovered three ice cores (308.6, 93.2 and 34.5m) from the Guliya ice cap (summit 6710 m a.s.l) in the far western Kunlun on the Qinghai–Tibetan Plateau, China. Guliya resembles a “polar” icecap with 10 m, 200 m and basal temperatures of –15.6°, –5.9° and –2.1°C, respectively. The 308.6 m core to bedrock is the longest ice core retrieved from an elevation greater than 4000 m a.s.l. and provides the first ice-core history from the western side of the Qinghai Plateau. The Plateau experiences a pronounced annual precipitation cycle during which 70–80% of annual total precipitation falls in the summer monsoon season. This leads to a marked visible stratigraphy in the glaciers which allows accurate dating of the ice cores and reconstruction of the net mass accumulation. This paper presents (1) the results of the geophysical program to determine ice thickness, ice flow and surface topography, (2) an assessment of net accumulation from stake measurements, snow pits and shallow core samples, and (3) the analyses of the upper 100 m of the 308.6 m core which provide a 1000 year history, including the ‘“Little Ice Age”, which is compared with Chinese historical records. Extended periods of positive accumulation on Guliya are closely contemporaneous with dry periods in eastern China. A trans-Pacific teleconnection is suggested by the strong temporal coherence between extended wet and dry phases on Guliya and on the Quelccaya ice cap, Peru.

Reconstruction of a 1436‐year soil moisture and vegetation water use history based on tree‐ring widths from Qilian junipers in northeastern Qaidam Basin, northwestern China

“…After passing a 31-year moving average filter to the time-series, significant low-frequency variation patterns can be seen, including prominent dry periods during 700-800 AD, 1100-1200 AD, 1425-1525 AD, and 1650-1750 AD, wet periods around 1225 AD, 1350 AD, and 1525-1650 AD, and a general trend toward a wetter condition during the most recent 300 years. The recent trend to a wetter condition conformed to the ice accumulation record during 1600-1980 based on the ice core taken from the Dunde Glacier (38°06 N, 96°24 E, 5325 m) northwest of the study region (Thompson et al, 1995). The wetter trend was also corroborated by a recent study in northern Pakistan, in which a reconstructed precipitation record based on tree-ring data indicated that the 20th Century was the wettest period during the past millennium (Treydte et al, 2006).…”

Support for global climate reorganization during the “Medieval Climate Anomaly”

“…A lower resolution reconstruction developed from a nearby core (Jiang et al 2005) indicates a similar magnitude of cooling during the transition from the MCA into the LIA. As discussed by Sicre et al (2008a), the Thompson et al (1995), Yang et al (2009); see also Wang et al (2007), data shown in 30. Yucatan May-October precipitationevaporation Lake core, various indices Hoddell et al (1995) MCA warming on the North Iceland Shelf appears to have resulted from enhanced poleward transport of the warmer waters from the North Atlantic Drift in the North Iceland Irminger Current, possibly due to increased southwesterly winds or to changes in transport associated with the AMOC.…”

“…3; numbers correspond to entries in Table 3 Seager et al (2007Seager et al ( , 2008 Kenya; Halfman et al 1994;Verschuren 2004) and from southern Oman (Fleitmann et al 2003; Fig 3L). (Thompson et al 1995;Wang et al 2007; Fig. 3M).…”

Mechanisms leading to the 2016 giant twin glacier collapses, Aru range, Tibet

“…However, sensitivity test (see 30 supplementary material, Figure S1) show that the temperate area remains similar for a basal heat flux comprised between 6.0 10 -2 and 1.2 10 -1 W m -2 and disappear at 2.0 10 -2 W m -2 . Measurement in Guliya Ice Cap (Thompson et al, 1995) and unlikely. Also, modeled thermal regime and friction reconstruction, which are almost independent, show a good accordance between the localization of sliding and modeled temperate areas giving confidence in our results (see section 5.2).…”

“…We assume a basal heat flux of 8.0 10 -2 W m 2 for the enthalpy equation according to heat flux measured in boreholes at Guliya ice cap (6200 m a.s.l., 200 km north to Aru range) (Thompson et al, 1995) and geothermal heat flux modeled in the region (Tao and Shen, 2008). 25…”