Early Summer Temperature History in Northeastern Kazakhstan during the Last 310 Years Recorded by Tree Rings

At the south slope of Altai Mountains,northeastern Kazakhstan,the tree ring width from the upper treeline was sensitive to the temperature at the early stage of its growth season.Under the climate warming background,tree ring width stably responded to temperature,hence,tree ring width was the prior proxy of past temperature change in this area.By using tree ring samples,this paper extracted the climatic information from tree ring width,established the transfer function between tree ring width chronology and mean June temperature,reconstructed the temperature history during the last 310 years from Katongkalgai weather station at northeastern Kazakhstan.The explained variance of the transfer function was 42.7%.Because the instrumental data was long,the independent test was applied for the transfer function,and all the test parameters indicated that the function was stable and reliable.The reconstructed mean June temperature series in this paper was coincident with the neighboring area such as west Altai in China and north slopes of Altai Mountains.The temperature fluctuation in 19th century was most obvious;the longest warm and cold period happened at this stage.Spectral analysis of the reconstructed series indicated that the cycle of 11 years was significant.This cycle was also coincided with the cycle of solar activity.The common cycle of reconstructed temperature and solar activity also proved that the tree ring width change synchronized with temperature and solar activity.