Precipitation record since AD 1600 from ice cores on the central Tibetan Plateau

Abstract

Abstract. Lack of reliable long-term precipitation record from the northern Tibetan Plateau has constrained our understanding of precipitation variations in this region. We drilled an ice core on the Puruogangri Ice Field in the central Tibetan Plateau in 2000 to reveal the precipitation variations. The well dated part of the core extends back to AD 1600, allowing us to construct a 400-year annual accumulation record. This record shows that the central Tibetan plateau experienced a drier period with an average annual precipitation of ~300 mm in the 19th century, compared to ~450 mm in the wetter periods during 1700–1780 and the 20th century. This pattern agrees with precipitation reconstructions from the Dunde and Guliya ice cores on the northern Plateau but differs from that found in the Dasuopu ice cores from the southern Plateau The north-south contrasts in precipitation reconstruction reveals difference in moisture origin between the south Tibetan Plateau dominated by the Asian monsoon and the north Tibetan Plateau dominated by the continental recycling and the westerlies.

Variability of summer humidity during the past 800 years on the eastern Tibetan Plateau inferred from δ<sup>18</sup>O of tree-ring cellulose

“…Similar conditions were observed for inner Asia and the northern TP (Pederson et al, 2014;Yang et al, 2013) but were not corroborated for the central TP (Grießinger et al, 2011). The moderate oscillation of our humidity reconstruction during the LIA contrasts results of increasing and decreasing moisture trends at different parts of the TP (Grießinger et al, 2011;Shao et al, 2005;Yao et al, 2008). We identified extreme interannual humidity variations by calculating the third standard deviation of the first differences.…”

Using glacier area ratio to quantify effects of melt water on runoff

“…Some implications can be inferred from the fractions. As discussed in previous section and literatures (Jansson et al, 2003;Yao et al, 2008), ice is transformed from precipitation. The transformation of precipitation to firn and then consolidation further to ice, and the movement of ice from the accumulation zone to the ablation zone are complicated and lengthy processes.…”

Millennium tree-ring reconstruction of drought variability in the eastern Qilian Mountains, northwest China

“…Wet conditions in the twentieth century were recorded in many other tree-ring based studies in the nearby regions, e.g., the middle Qilian Mountains (Yang et al 2011b), the Qaidam Basin (Zhang et al 2003;Sheppard et al 2004;Liu et al 2006;Shao et al 2010;Yang et al 2014), central eastern Tibet (Bräuning and Mantwill 2004), the Tienshan area (Li et al 2006) and in western and northern Mongolia (Davi et al 2009;Pederson et al 2013). Ice core records from the Guliya and Dunde in northern Tibetan Plateau and Puruogangri in central Tibetan Plateau all show a wetting trend in the last century (Yao et al 2008). Based on historical documents, Tan et al (2008) also show an increasing trend in Longxi precipitation over the last century.…”