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Hong Yin

2012-09-19
16:45:00 - 17:20:00

101 , Mathematics Research Center Building (ori. New Math. Bldg.)

Understanding of past climatic variability over the Northeast China is limited because of the lack of long-term climatic records. Here we reconstruct the annual mean temperature since A.D. 1765 based on tree-ring data in the Eastern part of the Northeast China. The reconstruction series can account for 45.8% of the annual temperature variance in the instrumental period (1959 to 2002).Six cold periods and five warm periods were identified based the 11-year moving average of reconstructed annual temperature series. The periods of 5.6-year and 3.8-year are found significant with a 99% confidence based on the power spectrum method. Significant abrupt changes with a 99% confidence are observed for around 1817,1839,1867,1913 and 1937with a 30-year moving T-test. Comparisons with other paleoclimatic proxies show that some cold and warm periods coincide with Siberia, Japan, China and Northern Hemisphere temperature. After strong volcanic eruptions in 1815, 1883, 1902, 1912 and 1991, the reconstruction temperature are on a low side. Especially after the 1912 volcanic eruption, the duration of the cooling period is longest from 1912 to 1921.

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