QUANTITATIVE RECONSTRUCTION OF LAKE LEVEL FLUCTUATION IN HUANGQIHAI FROM 1885 TO 2010 BASED ON GRAIN SIZE ANOMALY INDEX FROM HQH4 CORE SEDIMENT
Reconstructing the paleoclimate environment based on sedimentary sequences is a basic task in studying global change.The preferred indicators should be sensitive parameters in various indicator systems.However,various environmental background changes will blur its sensitivity and distort the reconstruction results.We created a 17-parameter grain size index system to develop grain size anomaly indexes to quantitatively reconstruct the lake level fluctuations of Huangqihai(Huangqi Lake),a closed lake located in the agro-pastoral ecotone of the East Asian monsoon region from 1885 to 2010.Results show that the anomaly index has a very sensitive correlation with lake surface fluctuations,and its sensitivity is much greater than that of ordinary particle size indicators.The years 1885～1895 and 1950～1985 were the high lake level stage of Huangqihai,and the years 1895～1950 and 1985～2010 were the low lake level stage.This result is consistent with the results revealed by sedimentary facies,basin precipitation records,remote sensing,and literature records.However,for the years 1990～2010,the particle size anomaly index was not related to the lake level fluctuations,indicating that the reasons for the rise and fall of the lake level at this stage were complex and obviously disturbed by human activities,such as river damming and groundwater extraction.This study created a quantitative method to reconstruct the lake surface fluctuation history of closed lakes based on the sediment particle size anomaly index,which provided a reference for studying global climate change.
万方数据
维普
