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Seven different tree-ring parameters (tree-ring width, earlywood width, latewood width, maximum density, minimum density, mean earlywood density, and mean latewood density) were obtained from Qinghai spruce ( Picea crassifolia) at one chronology site in the Hexi Corridor, China. The chronologies were analyzed individually and then compared with each other. Growth-climate response analyses showed that the tree-ring width and maximum latewood density (MXD) are mainly influenced by warm season temperature variability. Based on the relationships derived from the climate response analysis, the MXD chronology was used to reconstruct the May-August maximum temperature for the period 1775-2008 A.D., and it explained the 38.1% of the total temperature variance. It shows cooling in the late 1700s to early 1800s and warming in the twentieth century. Spatial climate correlation analyses with gridded land surface data revealed that our warm season temperature reconstruction contains a strong large-scale temperature signal for north China. Comparison with regional and Northern Hemisphere reconstructions revealed similar low-frequency change to longer-term variability. Several cold years coincide with major volcanic eruptions. [ABSTRACT FROM AUTHOR]

Abstract: Drought is a recurring phenomenon in north-central China. Long-term information about the history of drought is still limited because the instrumental records for many areas in north-central China go back only a few decades at best. This paper presents an earlywood width (EWW) chronology of Chinese pine (Pinus tabulaeformis) in the Shimen Mountains, Tianshui, eastern Gansu, north-central China. The climate-response analysis shows that April–July precipitation is the main factor limiting the earlywood growth of Chinese pines in the Shimen Mountains, Tianshui. Based on the EWW chronology, an April–July precipitation reconstruction for the period A.D. 1629–2008 was developed for Tianshui. The climate/tree-growth model accounts for 41.6% of the observed precipitation variance during the period 1953–2008. Spatial analysis shows that the precipitation reconstruction contains a strong common drought signal for north-central China. Reconstructed drought events are compared to a precipitation reconstruction of Huashan and historical archives for north-central China. The results reveal common climatic extremes over much of north-central China. Moreover, some dry periods coincided with solar minima or volcanic eruptions over the past several hundred years. Multi-taper spectral analysis reveals the existence of significant 3.8-year (90%), 3.1-year (95%), 2.7-year (99%), 2.4-year (99%) and 2.0-year (99%) periods of variability. The linkages to the Asian-Pacific Oscillation Index suggest regional precipitation variations may be linked to the East Asian summer monsoon circulations. [Copyright &y& Elsevier]

Abstract: July–June precipitation has been reconstructed back to A.D. 1464 for the Baluntai region on the southern slope of the central Tien Shan Mountains, China, using the Picea schrenkiana tree-ring width. The reconstruction explains the variance of 51% in the observed precipitation from 1959 to 2005. By employing a 21-year moving average to the reconstruction, nine periods with above average reconstructed precipitation comprised ∼1474–1503, 1550–1577, 1588–1619, 1658–1713, 1790–1812, 1833–1867, 1890–1907, 1923–1944, and 1988–1995∼; eight periods with below average reconstruction consisted of 1504–1549, 1578–1587, 1620–1657, 1714–1789, 1813–1832, 1868–1889, 1908–1922 and 1945–1987. The wet/dry periods of the reconstructed precipitation correspond well with other reconstructions. Some droughts in the historical documents are also precisely captured in the reconstruction. Precipitation variations for the southern slope of the central Tien Shan Mountains are roughly synchronous with that of the northern slope in the recent ∼300 year. Power spectral and wavelet analysis demonstrated the existence of significant ∼100-y, ∼60-y, ∼50-y, ∼16-y, ∼10-y and ∼2-y cycles of variability. [Copyright &y& Elsevier]