Study Of δ¹³C Feature In Tamarix Cone And Environmental Change In Lop Nur Region, China

Desert Area is an important component of the global system.It has unique characteristics of environmental change.The investigated subject of this paper is Tamarix Cone in Lop Nur region.It is important to reflect and analyze the environment by distilling the information of annual stratum stable carbon isotope,on the basis of inspecting and observing in the field and testing the analytical means.The main process and conclusions are as follows:We analyze theδ¹³C contained in annual stratum of Tamarix Cone in Lop Nur region. In order to highlight the climate change by high-frequency information recorded,we eliminate the low-frequency information from interference factor.Based on the correlation test between high-frequency change and climate factor,we attain the best multivariate regression equation of△δ¹³C and climate factor by using stepwise regression.The correlation coefficient is 0.716 and the explanation rate of variance is 51.3%.Generally,the result shows that the annual stratum stable carbon isotope is restricted by several climatic factors in this area.Through constructing transfer function of information,we reconstruct the history of average relative humidity from Aug.to Oct.,wind speed from Apr.to May and the annual mean temperature since 1839 of Lop Nur region.The analysis illustrate that the reconstructed result reflects preferably the historical climate variation during the past 168 years in this area.δ¹³C in Tamarix Cone can show the changes of climate elements,consequently offer good basis for studying the past and future variation of environment in Lop Nur region.In annual stratum theδ¹³C series shows that it has a reasonable record for sunspot and ENSO in this area.And the high-frequency information is lower in ENSO year.Analysis of power spectrum indicates that the quasi-periodic oscillations of 42.00 a,10.50 a,8.40 a,4.01 a,3.36 a and 2.85 a are involved in the high-frequency information series.The quasi-periodic of 4.01 a is consistent with 4.4 a which is the period of ENSO event.At the same time the quasi-periodic of 10.50 a reflects the active cycle of sunspot around 11a.