Decadal climatic variations recorded in Guliya ice core and comparison with the historical documentary data from East China during the last 2000 years

The high-resolution records of δ18O and snow accumulation variations from the Guliya ice core provide valuable data for research on climatic variations at a decadal resolution during the past 2000 years in China. Based on the ice core data, five spells have been divided: the warm and wet period before 270 AD, the cold and dry period between 280 and 970 AD, the moderate and dry period between 970 and 1510 AD, the well-defined' Little Ice Age 'with drastic cold-warm fluctuations between 1510 and 1930 AD and the warming period since 1930 AD. According to the combination of temperature and precipitation, cold events (55 times) surpass warm ones (26 times) , and dry events (55 times) surpass wet ones (45 times) . Cold-wet events (14 times) are less than cold-dry ones (16 times) , while warm-wet events (10 times) are more than warm-dry ones (4 times) . If the difference of 2‰ in δ18O (corresponding to 3K in temperature) between two or three adjacent decades is taken as the criterion of it, the abrupt change has taken place 33 times or so since the 3rd century. Among them are four large ones, occurring in 250-280, 550-580, 1220-1260, and 1520-1560 AD respectively. Comparison of the ice core data with the latest comprehensive research results on historical documents of East China shows that the great climatic events appeared simultaneously or at the same age in the ice core record and in the documentary data, suggesting that consistences and similarities in climatic variation among different areas are far away from each other in the lower to mid-latitudes. However, there is a great difference between them during the Medieval Warm Period, which is conspicuous in the historical documents but not in the ice core. In addition, the first cold event of the Little Ice Age on East China was 60 years earlier than that of the Guliya Ice Cap, when the degree of cooling in West China is more intensive than that of East China. But the third cold event in East China lagged behind that in West China during the late 19th century. The 1820s cold event in both West and East China may be caused by the magnificent Tambora volcanic eruption in 1815.

The high-resolution records of δ18O and snow accumulation variations from the Guliya ice core provide valuable data for research on climatic variations at a decadal resolution during the past 2000 years in China. Based on the ice core data, five spells have been divided: the warm and wet period before 270 AD, the cold and dry period between 280 and 970 AD, the moderate and dry period between 970 and 1510 AD, the well-defined" Little Ice Age "with drastic cold-warm fluctuations between 1510 and 1930 AD and the warming period since 1930 AD. According to the combination of temperature and precipitation, cold events （55 times） surpass warm ones （26 times）, and dry events （55 times） surpass wet ones （45 times）. Cold-wet events （14 times） are less than cold-dry ones （16 times）, while warmwet events （10 times） are more than warm-dry ones （4 times）. If the difference of 2‰ in δ18O （corresponding to 3K in temperature） between two or three adjacent decades is taken as the criterion of it, the abrupt