Past changes of spring drought in the inner Tianshan Mountains, China, as recorded by tree rings

Abstract

Drought is a common natural disaster in arid Central Asia, and the severity and frequency of drought and other hydroclimatic events are critical to the region's ecology and its residents' livelihoods. In particular, water resource management requires reliable knowledge of climatic variability and annual and centennial drought patterns. In this paper, we establish a 587-year tree ring chronology using 215 Schrenk spruce (Picea schrenkiana Fisch. et Mey) samples and reconstruct a spring Palmer Drought Severity Index (PDSI) for the inner Tianshan Mountains spanning the 1645-2008 period. The reconstruction explains 40.3% of the variance during the sub-period for which we also have reliable observational data . Cross-validation during this common period also supports our reconstruction model. Spatial correlation analyses with gridded PDSI data show that our PDSI reconstruction reveals a strong regional drought signal for the central and western Tianshan Mountains.

A 333-year record of the mean minimum temperature reconstruction in the Western Tianshan Mountains, China

“…12a shows that the reconstruction values were significantly correlated with the North Atlantic Oscillation Index in the summer (SNAO, Folland et al, 2009), with the high-frequency change in March to September (r = 0.221, p < 0.05, 1930 and the low-frequency change occurring with the 5-year moving average (r = 0.366, p < 0.01, 1930-2012). The same conclusion has been found in the reconstruction of precipitation over the last 300 years in the west-central Tianshan Mountains, the reconstruction of drought in the past 364 years in the central and western Tianshan Mountains, and the streamflow reconstruction of the eastern Tianshan Mountains over the past 330 years (Wang et al, 2015;Chen and Yuan, 2016;Zhang et al, 2017). The reconstruction results were correlated with the Western Pacific Oscillation Index (WPO, https://crudata.uea.ac.uk/cru/data/wpo/), with the highfrequency change in April to August (r = 0.331, p < 0.01, 1950-2012) and the low-frequency change occurring with the 5-year moving average (r = 0.528, p < 0.01, Fig.…”

“…(Wen et al, 2006;Chen et al, 2012a). The mean minimum temperature reconstruction had a good correspondence with the drought events in the Xinjiang region, and the values of the drought events were significantly higher than the average reconstructed temperatures, especially in some extreme drought years, such as 1775, 1919, and 1945(Chen et al, 2013Zhang et al, 2017). Radial growth of trees is also responsive to volcanic eruptions and temperature changes had been importantly affected by many upper westerly circulation and low latitude tropics massive volcanic eruptions in central Asia (Chen et al, 2012b).…”

The Radial Growth of Schrenk Spruce (Picea schrenkiana Fisch. et Mey.) Records the Hydroclimatic Changes in the Chu River Basin over the Past 175 Years

“…In previous dendroclimatological studies in the Tianshan Mountains, we found that long-term changes in moisture have a strong local character [7,9,10,26,38,39]. The consistency of the change decreases rapidly with increasing distance.…”

Impacts of Global Warming on the Radial Growth and Long-Term Intrinsic Water-Use Efficiency (iWUE) of Schrenk Spruce (Picea schrenkiana Fisch. et Mey) in the Sayram Lake Basin, Northwest China

“…All pooled samples were grounded into powder in a ball mill (MM 400, Retsch GmbH, Germany), and the α cellulose was extracted using the method of Brendel et al [45]. This method has been widely used in dendroclimatology studies [34,35,46].…”

“…There are a large number of Schrenk spruce (Picea schrenkiana Fisch. et Mey) virgin forests in this region and this species has been shown to be suitable for dendrochronological study [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. However, few studies have discussed the relationship between C a , climate, radial growth, and iWUE in the Tianshan Mountains [39,40].…”