Response Of Radial Growth Of Larix Sibirica To Climate And Climate Reconstruction In The Altai Mountains

Located in northwest China,The Altai Mountains have a high dimension and altitude and are vulnerable to climate change.Siberian Larch is the dominant tree species in the Altai Mountains and is sensitive to climate change.In this paper,three tree ring chronologies were developed based on larch tree ring samples collected from 9 sampling sites in the Altai Mountains from2019 to October 2021.The meteorological data of Haba river,Altay,Fuyun and Qinghe meteorological stations in Altay region were selected to analyze the trend and characteristics of climate change in Altay region.The chronology characteristics of 9 sampling points were compared and analyzed,and the correlation between meteorological data and standardized chronology of Larch was analyzed.The chronology with high correlation with climate factors was selected for climate reconstruction,and the results of climate reconstruction were tested and analyzed.The results of the study were as follows:(1)The standardized chronology of tree ring width established at 9 sampling points in Altay region,and the characteristic parameters of each chronology are represented.The chronology is suitable for climate response and analysis.Altay region width 9 sampling points set up trees round standardization chronology,SKE,XDG,DEQ,JDY contains more abundant climate information,KEM and KEQ chronology characteristic parameters are relatively poor.In addition,the closer the chronology is,the greater the number of correlation between chronology,and the first-order autocorrelation coefficient of chronology is related to geographical location.Overall,the characteristics of the chronology indicate that the chronology is suitable for climate response and analysis.(2)The climate change characteristics of Altay region were studied by calculating the climate tilt rate of temperature and precipitation based on the meteorological data of corresponding meteorological stations.The results showed that both temperature and precipitation in Altay region had an obvious upward trend,and both increased significantly from May to October.The water and heat increased in the same period,and the climate tended to be warm and humid.Meanwhile,the tilt rate of mean temperature and extreme temperature is the largest in Fuyun area,and the temperature rising trend is the most obvious.Altay regional climate change characteristics are not obvious.(3)The correlation analysis between larch and climate factors showed that jiadengyu chronology and Shakuerbulak chronology had the highest correlation with air temperature,and the temperature in the growing season significantly promoted the growth of Larch in Jiadengyu area,but significantly inhibited the growth of Shakuerbulak.Shakurbulak chronology has the highest correlation with the average minimum temperature in July of that year,reaching-0.616,which is suitable for climate reconstruction.At the same time,the influence of temperature on radial growth of larch was related to other habitats.At the same time,the correlation between the 9 chronologies and precipitation was lower than that of air temperature.The chronology of Xiaodong Gou was significantly negatively correlated with precipitation in the growing season,and the chronology of Jiadengyu was significantly negatively correlated with precipitation in the winter of last year.Some chronologies have no significant correlation with precipitation.The response function analysis of chronology and climate elements showed that the function model fitting effect between chronology and climate elements was good except the Kurmut chronology,and the trend between measured and simulated values of tree-ring width index was relatively close.(4)In the process of temperature reconstruction,it is found that the reconstruction equation of temperature in rich accumulation area is stable and reliable.The reconstructed temperature sequence experienced 10 warm periods and 9 cold periods.The longest warm period spanned25 years(1850-1875).In terms of frequency and extreme value,the reconstructed temperature series has 36 warm years.The warm year is 5 years;The colder year is 36;Cold years are 4years,accounting for the total;Normal year 148 years.The maximum extreme value was17.86? in 1753,which was 2.98? higher than the average reconstructed temperature.The minimum value was 12.63 ? in 1776,2.3 ? lower than the reconstructed average.The reconstruction sequence of haba River lasted 247 years,38 years of warm years.The warm year is 13 years;The colder year is 60 years;The cold year is 14 years;Normal year 124 years,accounting for the total.In the reconstructed temperature series,the maximum extreme value is 66.60 ?,which is 3.1 ? higher than the average reconstructed temperature.The minimum value was 60.59?,2.9? lower than the reconstructed mean.