An 800-Year Temperature Reconstruction in Daihai Lake Area of Inner Mongolia
CAO Jian-Ting 1, JIN Zhang-Dong 2, SHEN Ji 2, WANG Su-Min 2 (1. College of Water Resources and Environment, Hohai University, Nanjing, Jiangsu 210098; 2. Nanjing Institute of Geography and Limnology, the Chinese Academy of Sciences, Nanjing, Jiangsu 210008)
Combined the analysis of the oxygen isotopic composition of the authigentic carbonates in sediment core of Daihai Lake, establishment of the function between water salinity and oxygen isotopic composition, with the reconstruction of lake water salinity, the temperature of lake water during the carbonate crystallization was reconstructed. Then the yearly average air temperature was deduced according to the difference between the lake water temperature of the carbonate crystallization and the yearly average air temperature. The deduced curve of yearly average air temperature during the past 800 years showed three obvious stages, namely the Medieval Warm Period, the Little Ice Age, and the warming stage of the last hundred years. The temperature of the Medieval Warm Period in the research period was 1℃ higher than that of average temperature of recent 30 years. From 1240 A. D. to 1300 A. D., the temperature decrease 1.8℃, showing abrupt changes of climate. The temperature in the coldest period of the LIA was 2.2℃ lower than that of present. Since 1880 A.D., the temperature have kept warming continuously, and the increasing amplitude reaches more than 1℃. Different from the climate feature recorded by Guliya ice core, in the west part of China, the last hundred years' warming in Daihai Lake area has not reached the warm degree of the Medieval Warm Period, probably suggesting that the influence of global warming on the west China is more heavier than the east China.