| Climate change is closely related to the human living environment and climate change is leading to environmental change,which has a negative impact on the environment.The research on climate change has attracted the attention of experts and scholars at home and abroad.There are many substitute indexes for climate change research.Tree ring have the advantages of dating is simple and accurate?strong continuity?long record period?widely distributed all over the world and the information is easy to obtain.In addition,there is an obvious response relationship between tree rings and climate.Therefore,tree ring has become one of the most widely used and accurate alternative materials in climate change research.The Zhenglan county of Inner Mongolia is an ecologically sensitive area because of its drought,lack of rain and serious grassland degradation.The Hunshandake sandy land in the north of Zhenglan county is the source area of sand of the inland,and desertification is increasing under the influence of climate change and human activities.Therefore,this paper will study the historical climate change of Zhenglan county? analyze the impact of climate change on environmental change and explore Eco-environmental governance scheme based on climate change.Samples of tree rings used in this paper are elm cores.The samples were collected in Hunshandake sandy land in the north of Zhenglan county,Xilingol League,Inner Mongolia.After processing and analyzing the collected samples,the following conclusions are drawn:1.Using ARSTAN program to generate three kind of chronologies from each of ring width sequence(early wood width sequence,late wood width sequence and ring width sequence)of Baoshaodai country and Nart country,the three kind of chronologies respectively named standardized chronology(STD),residual chronology(RES)and autoregressive chronology(ARS).Finally,eighteen chronologies are obtained.After chronological statistics comparison and statistical analysis,we chose to merge the ring width standard chronology of Baoshaodai country and Nart country into a regional chronology.The effective length of the regional chronology is 246 years(1766-2011).2.We analyzed the correlation between regional chronology and monthly mean temperature?average minimum temperature?average maximum temperature?precipitation and evaporation capacity of Zhenglan County Meteorological Station.The results showed that there was a significant negative correlation between regional chronology and the mean April-May maximum temperature,and the correlation coefficient is-0.72.3.We established the reconstruction regression equation,taking the regional chronology as the independent variable(RC)and the mean April-May maximum temperature as the dependent variable(Tmax4-5).The reconstruction regression equation is: Tmax4-5=-9.869RC+24.967.The reconstruction regression equation's variance explanatory quantity is 51.35%,the adjusted variance interpretation is 50.38%,the F value is 52.78,and the reconstruction equation has passed the reliability test.4.There are five periods with significantly higher temperature of the reconstruction sequence(1786-1801,1816-1843,1876-1890,1904-1925,1981-2006)and six periods with significantly lower temperature of the reconstruction sequence(1771-1785,1802-1815,1844-1861,1865-1875,1891-1903,1926-1980).The warm period of reconstruction sequence is 107 yeras,accounting for 46% of the whole reconstruction period,while the cold period is 121 yeras,accounting for 52% of the whole reconstruction period.5.Detecting the periodicity of the reconstruction sequence,the results show that the reconstruction temperature sequence has 2-3.5a and 33-51.28 a cycles at 95% confidence level,and 33-40.98 a and 2-3a cycles at 99% confidence level.Meanwhile,2-3a period coincides with ENSO period,33-51.28 a period is very close to Bruckner(28-42 years). |
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