Rainfall history for the Hexi Corridor in the arid northwest China during the past 620 years derived from tree rings

Abstract

ABSTRACT:We present a 620-year long ring width record from the middle Qilian Mountains, where it is presently controlled by the Westerlies. The chronology was developed from Qilian juniper (Sabina przewalskii ) growing at sites near the western distribution limit of the species in the northern Qilian Mountains, Gansu Province, China. A linear regression model between ring width and annual (July to June) precipitation accounts for 34.9% of the observed instrumental precipitation variance during the period 1952 to 2007. Spatial correlation analyses between the reconstruction and gridded precipitation data shows that the annual precipitation reconstruction captures regional climatic variations over the Qilian Mountains and the nearby Hexi Corridor. We also show the scaled standard chronology adjusted to the mean and variance of the instrumental data. Relatively wet periods are identified for AD 1390-1413, 1425-1450, 1530-1649, 1792-1920, 1937-1949 and 1980-1985. Dry conditions prevailed during AD 1414-1424, 1451-1529, 1650-1791, 1921-1936, 1950-1979 and 1986. In comparison with the regression-based reconstruction, the scaled reconstruction indicates considerably wetter conditions during 1390-1413, 1425-1450, 1570-1630 and 1790-1920. The interval AD 1451-1529 was the most intense and longest drought epoch in the Hexi Corridor over the past six centuries. This drought was not only recorded in the Qilian Mountains but also occurred in northern and eastern China. It might be caused by a substantial weakening of the Asian summer monsoon induced by the joint effects of solar and volcanic activities at that time. Our results also suggest that the Hexi Corridor was under the control of the Asian monsoon circulation on inter-decadal to centennial timescales in the past centuries.

Millennial minimum temperature variations in the Qilian Mountains, China: evidence from tree rings

“…Such discrepancies seem to be a common problem in tree-ring-based temperature reconstructions in China, in which the agreement between observed data and estimated data became worse before the 1990s in many regions across China (Deng et al, 2013;Fan et al, , 2010Gou et al, 2007b;Lv and Zhang, 2013;Shi et al, 2010;Song et al, 2014;Yang et al, 2009bYang et al, , 2010Zhang et al, 2013;Zhu et al, 2011a). Similar issues were also found for the tree-ring-based precipitation reconstructions Fan et al, 2008b;Liu et al, 2011;Shao et al, 2005;Yang et al, 2011Yang et al, , 2014Y. Zhang et al, 2011;Zhang et al, 2014).…”

A 457-year reconstruction of precipitation in the southeastern Qinghai-Tibet Plateau, China using tree-ring records

“…For June and September of 1977-1979, days with rainfall greater than 20 mm occurred much more frequently than in other years. Tree-ring records failed to accurately record rapid and intensive rainfall, especially for the steep slopes at our sampling site, and this is a common phenomenon in tree ring research [26,27].…”

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

“…This long drought period is widely reported in many tree-ring width based drought or precipitation reconstructions in northeastern Tibetan Plateau (Gou et al 2014), including the source of the Yellow river (Gou et al 2010), the Qaidam Basin (Zhang et al 2003;Sheppard et al 2004;Shao et al 2005;Liu et al 2006;Yang et al 2014), the middle and west Qilian mountains (Yang et al 2011a, b;Zhang et al 2011;Sun and Liu 2012), and the nearest PDSI grid in (Cook et al 2010)'s monsoon Asian drought reconstruction dataset. It is also recorded in various other paleoclimatic archives, and obvious in a tree-ring oxygen isotope based precipitation reconstruction from the Qaidam Basin (Wang et al 2013).…”