Three well-dated Sabina Przewalskii ring-width chronologies from Dulan, China, have been used to reconstruct annual precipitation (from prior July to current June) variations on the northeast Tibetan Plateau since 850 AD. The reconstructions account of the instrumentally recorded precipitation variance are: 54.7% for the period of 1385-2000AD; 50.5% for 1099-1384AD and 45.7% for 850-1098AD. On the millenary scale, the precipitation variation over this region displays "W" shape, which has three peaks and two valleys. The precipitation is low during 1571-1879 AD, and high during 1880-2000 AD. 1900-2000 AD is the century with the highest precipitation over the northeast Tibetan Plateau in the last 1000 years, and 1962-2000 is the period with the highest precipitation, and the highest variability of precipitation as well in the last 1000 years. The reconstructed series also reveals that the variability of annual precipitation is large when the precipitation is more, and contrarily, variability is small when the precipitation is low. With the temperature increasing obviously in the 20th century, the precipitation in the study region significantly increased too, the variability of precipitation became larger, and drought and flooding occurred more frequently.The yearly tree-ring width (high frequency signal) series in this region reflects the local annually precipitation variation. However, the series with 40-year moving average (low frequency signal) corresponds to the Northern Hemisphere temperature variations on the decadal to centurial scale. It correlates significantly with seven temperature curves of the Northern Hemisphere in the different time spans. For example, the correlation coefficients with the most temperature curves are around 0.9 during the period of 1852-1982 AD. In general, the temperature and the precipitation change synchronously in the Dulan region. It means that low temperature corresponds to low precipitation, and

Chinese pine (Pinus tabulaeformis Carr.) trees from the Helan Mountain range in central China have been used to reconstruct total January–July precipitation from AD 1775 to 1998. For the calibration period R2adj = 0.52. Narrow rings are associated with below-average precipitation from March through August. Wide rings are produced in years when the East Asian summer monsoon front arrives early. We use local historical writings over the last 300 years about extreme climatic conditions between spring and early summer to verify the extreme years. Most of the extreme dry years could be identified in local historical documents. Another East Asian summer monsoon front related precipitation reconstruction from northern Helan Mountain is also used to verify this reconstruction. They are well correlated from year to year, with a correlation coefficient of 0.52 (N = 218), and the wet or dry extreme events are well matched in many cases. This comparison could indicate a spatial and temporal connection of spring to early summer climatic conditions for the southern to northern portion of the Helan Mountain region. The sustained wet period before the 20th century lasts from the 1850s to the 1890s, and the longest dry period before the 20th century is in the 1830s and 1840s, largely coinciding with a spring–summer drought in Kashmir. Overall, multiyear fluctuations, such as the spectacular large-scale drought of the late 1920s and droughts in the 1830s–1840s and the 1970s, are well captured in this reconstruction, but only the 1970s drought is in the instrumental period. The reconstruction shows increasing variance from the 18th to the late 20th century.

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Rapid warming has been observed in the high-altitude areas around the globe, but the implications on moisture change are not fully understood. Here we use tree-rings to reveal common moisture change on the southeastern Tibetan Plateau (TP) during the past five centuries, and show that regional moisture change in late spring to early summer (April-June) is closely related to large-scale temperature anomaly over the TP, with increased moisture coincident with periods of high temperature. The most recent pluvial during the 1990s-2000s is likely the wettest for the past five centuries, which coincides with the warmest period on the TP during the past millennium. Dynamic analysis reveals that vertical air convection is enhanced in response to anomalous TP surface warming, leading to an increase in lower-tropospheric humidity and effective precipitation over the southeastern TP. The coherent warm-wet relationship identified in both tree-rings and dynamic analysis implies a generally wetter condition on the southeastern TP under future warming.

A great impediment of Asian monsoon (AM) climate studies is the general lack of long‐term observations of large‐scale monsoon variability. Here we present a well‐verified reconstruction of temporal changes in the dominant summer moisture pattern over China and Mongolia (CM), based on a network of tree‐ring chronologies (1600–1991). The reconstruction reveals significant changes in the large‐scale AM over the past four centuries, which coincide with dramatic episodes in Chinese history over the period of record. These episodes include the fall of the Ming Dynasty (AD 1644) and the catastrophic famine during China's Great Leap Forward (1958–1961). Overall, the reconstructed AM strength corresponds well with Northern Hemisphere temperature proxies over the past four centuries. Yet, this relationship has broken down in recent decades, raising the possibility that the major driving force of monsoon dynamics has shifted from natural to anthropogenic in nature.

[1] Statistical modeling techniques and the Vaganov-Shashkin (VS) forward model of tree ring formation were used to investigate tree growth response of Pinus tabulaeformis to climate variations in semi-arid north central China. Both statistical and process-based modeling techniques were shown to be capable of simulating and evaluating climate-tree growth relationships for the study area, but the process-based VS model produced results that were more physically interpretable. Statistical modeling results indicate that both moisture and temperature have significant effects on tree growth during the growing season, with the most important months being May-August. The VS modeled results validated the above statistical modeling results, and further clarified the effects on tree growth of the seasonal distribution of temperature and soil moisture, soil moisture status prior to the growing season, and the start and end dates of the growing season. Under current and projected climate scenarios, our modeling results suggest significant tree growth reduction in north central China, and the possibility that regional forests may reduce their capacity to sequester carbon.

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