基于线性趋势外推和GM(1,1)模型预测塔里木河下游胡杨年轮径向生长变化

Prediction of the radial growth of Populus euphratica in Tarim river downstream based on linear trend extrapolation and GM(1, 1) model

以塔里木河下游3个典型断面(喀尔达依、阿拉干、依干不及麻)1981―2001年胡杨年轮样本数据为基础,分析无生态输水工程背景下该区胡杨年轮生长变化的特征,并通过构建趋势外推模型和GM(1,1)模型,求得胡杨树木停止生长的时间段。研究发现:该区胡杨年轮宽度值在该时间段内存在时空一致性,整体呈下降态势,除阿拉干断面外,其它两断面下降趋势较为明显,年轮宽度突变年依次为:喀尔达依1988年、阿拉干1987年、依干不及麻1988年。结果表明:(1)两模型均通过了模型精度检验且精度较高。通过对比分析模拟结果,胡杨完全停止生长时间段相对误差仅为±1.5 a和±2.5 a;(2)运用趋势外推模型得3断面胡杨年轮停止生长的年份分别为2022年、2027年、2018年,该区胡杨年轮完全停止生长的区间为2018―2027年;(3)运用GM(1,1)模型预测得3断面胡杨年轮停止生长的年份分别为2025年、2032年、2015年,胡杨年轮完全停止生长的区间为2015―2032年。本研究可为塔里木河下游退化生态系统恢复提供理论依据。

Three typical sections of Tarim River downstream, based on the data of populus euphratica rings in 1981-2001, the characteristics of the growth change of populus euphratica in this area were analyzed, and by constructing the trend extrapolation model and GM（1, 1） model, The time period of the tree stop growth of populus euphratica was obtained. The results show that the value of the ring width of populus euphratica in this area is consistent in time and space, the whole is descending, except for the Arakan section, the other two sections are more obvious, The results show that：（1） Both models pass the model precision test and the precision is high. By comparing and analyzing the simulation results, the relative error of the total stop growth time of populus euphratica is only±1.5 a and ±2.5 a.（2） The three-section growth of populus euphratica with the trend extrapolation model is 2022, 2027, 2018, and the zone of the growth of populus euphratica rings in this area is 2018-2027.（3） using the GM（1, 1） model to predict the growth of the three-section populus euphratica in the year, respectively 2025, 2032, 2015, the total growth of the tree ring period is 2015-2032. This study can provide a theoretical basis for the restoration of degraded ecosystem in Tarim River downstream.