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A regional tree‐ring width chronology of Schrenk spruce (Picea schrenkiana) was used to determine the annual (previous July to current June) streamflow of the Kuqa River in Xinjiang, China, for the period of 1414–2015. A linear transformation of the tree‐ring data accounted for 63.9% of the total variance when regressed against instrumental streamflow during 1957–2006. The model was validated by comparing the regression estimates against independent data. High streamflow periods with a streamflow above the 602‐year mean occurred from 1430–1442, 1466–1492, 1557–1586, 1603–1615, 1687–1717, 1748–1767, 1795–1819, 1834–1856, 1888–1910 and 1989–2015. Low streamflow periods (streamflow below the mean) occurred from 1419–1429, 1443–1465, 1493–1556, 1587–1602, 1616–1686, 1720–1747, 1768–1794, 1820–1833, 1857–1887 and 1911–1988. The reconstruction compares well with the tree‐ring‐based streamflow series of the Tizinafu River from the Kunlun Mountains; both show well‐known severe drought events. The streamflow reconstruction also shows highly synchronous upward trends since the 1980s, suggesting that streamflow is related to Central Asian warming and humidification. Thus, the influences of the extremes and the persistence of low streamflows on local society may be considerable. Climatic changes in the watershed may be responsible for the change in the hydrologic regime of the Tarim Basin observed during the late twentieth century. [ABSTRACT FROM AUTHOR]

An annual ( July to June) precipitation reconstruction for the period AD 1760-2010 was developed from a Picea crassifolia regional tree-ring chronology from two sites in the northern mountainous region of the Hexi Corridor, NW China. This reconstruction explains 52.1% of the actual precipitation variance during the period 1951 to 2010. Spatial correlations with gridded land-surface data reveal that our reconstruction contains a strong regional precipitation signal for the Hexi Corridor and for the southern margin of the Badain Jaran Desert. Significant spectral peaks were identified at 31.9, 11.1, 8.0, 7.0, 3.2, 2.6 and 2.2 years. A large-scale comparison indicates that our reconstruction is more consistent with climate records of a Westerly-dominated Central Asia, and that the Westerlies have a greater impact on the precipitation in this region than the Asian summer monsoon. Our reconstructed precipitation series is significantly correlated with sea-surface temperature ( SST) in the tropical Atlantic Ocean (positive), the tropical Indian Ocean (positive), the western tropical Pacific Ocean (positive), and the western North Pacific Ocean (negative). The spatial correlation patterns between our precipitation reconstruction and SSTs of the Atlantic and Pacific Oceans suggest a connection between regional precipitation variations and the high-mid-latitude northern atmospheric circulations ( Westerlies and Asian summer monsoon). [ABSTRACT FROM AUTHOR]

Abstract: Three robust tree-ring density chronologies were developed for the western Tianshan Mountains of northwestern China. The chronologies were significantly correlated and form a regional chronology (GLD). The GLD had significant and positive correlations with temperature of warm seasons. Based on this relationship, the mean minimum temperatures of May to August were reconstructed using the GLD chronology for the period AD 1657 to 2008. The temperature reconstruction exhibited temperature patterns on interannual to centennial timescales, and showed that the end of the 20th century is the warmest period in the past 352years. The reconstructed temperature variation has a teleconnection with large-scale atmospheric–oceanic variability and captures long- and broad-scale regional climatic variations. [Copyright &y& Elsevier]

In this paper, ring-width chronologies of pine trees ( Pinus sylvestris var. mongolica) from one sampling site in the northern Greater Higgnan Mountains, China, were constructed. The results of growth-climate responses show that mean temperature is the limiting factor affecting radial growth of pine trees in the study area. Consequently, mean temperature from May to October from 1717 to 2008 has been reconstructed using the standard chronology. For the calibrated period (1957-2008), the explained variance of the reconstruction is 57%. The characteristics of the reconstruction expose that mean temperature has increased since the 1970s, and the decade 2000s and 1990s are also ranked as the warm decades on record. However, this period from 1970s to now is not exceptional within the past 300 years. By applying an 11-year moving average to the reconstruction, three warm periods and three cold periods are evident. The warm and cold periods of the reconstructed mean temperature correspond well with other reconstructions. Power spectral and wavelet analysis demonstrated the existence of significant ∼70- and ∼100-year cycles of variability. Furthermore, the reconstruction and North Atlantic Oscillation Index showed a significant positive correlation ( r = 0.34, n = 136, p < 0.0001). Copyright © 2012 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Wood from Siberian larch ( Larix sibirica Ledeb.) was collected in Hoboksar County, Xinjiang. Mean latewood densities (LWD) were measured by X-ray densitometry; individual series were first cross-dated and then combined to form a standard chronology. We developed a warm-season (June-August) temperature reconstruction of Zajsan Lake area in East Kazakhstan that spans 1600-2002 based on the standard chronology (LWD). The climate/tree-growth model accounts for 39.1% of the temperature variance from 1901 to 2002 and shows cold phase during the late 1600s early 1700s followed by a warmer period, with cooling again in the late 1700s early 1800s. Several severely cold warm seasons coincide with major volcanic eruptions. Some of the temperature variations also correspond to variations in solar activity. The similarities in trends of the Zajsan chronology (LWD) and the Qinghe chronology (LWD) in Altai Mountain show that there are common large-scale climatic forcings in Central Asian. The low-frequency change of temperature reconstruction is correlated positively with Northern Hemisphere temperatures. Copyright © 2011 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

July–June precipitation has been reconstructed to 1756 AD for the western Tien Shan Mountains, Central Asia, using the Picea schrenkiana tree-ring width. The reconstruction explains 31% of the variation in the observed precipitation from 1933 to 2009. Some extremely dry signals in the historical documents are captured precisely in this new reconstruction. Wet periods occurred during the periods of 1811–1828, 1843–1880, 1893–1915, 1929–1934, and 1983–2002, while the periods 1766–1810, 1829–1842, 1881–1892, 1916–1928, and 1935–1982 were relatively dry. Power spectral and wavelet analyses demonstrated the existence of significant 32-, 17-, and 2.6–7.4-year cycles of variability. An assessment of spatial correlation analysis and the significant correlation coefficients between the reconstructed precipitation series and three precipitation reconstructions indicate that our reconstruction might contain multiple large-scale climatic signals in the low-frequency domain. A wetting trend in the eastern Central Asia since the 1970s decades was also captured by this reconstruction. [ABSTRACT FROM AUTHOR]