1850年以来川西高原北部植被气候生产潜力时空变化特征

Spatial and Temporal Variations of Climate-Induced Potential Productivity of Vegetation in Northwestern Sichuan Plateau Since 1850

为了研究历史时期川西高原北部的植被气候生产潜力时空变化特征,利用采自四川省阿坝州境内4个样点的树轮样本建立树轮宽度标准年表,使用Miami模型重建了1850—2010年阿坝州13个站点的气候生产潜力。结果表明:树轮宽度标准年表具有表征过去气候变化的潜力,并且与温度决定的气候生产力(M T)有很好的对应关系。阿坝州M T呈自东南向西北递减的分布状况,经验正交函数分解(EOF)第一模态为全区一致变化型,其中西部和北部为大值带。1850—1950年M T没有明显的变化趋势,1950—1980年逐渐减小,随后一直到2010年迅速增加。阿坝州M T在1967年和1990年前后分别出现两次突变,同时M T有显著的准2 a周期和4~5 a周期。研究表明利用树木年轮资料重建历史时期植被气候生产潜力是一种有效的方法,过去161 a阿坝州M T具有明显的空间分布差异和年际、年代际波动,尤其20世纪80年代以来M T的增加速率和绝对值都达到1850年以来最大,这也从侧面为全球变暖提供了证据。

In order to study the spatial and temporal variations of climate-induced potential productivity of vegetation in Northernwestern Sichuan Plateau,four tree ring samples from Aba Prefecture in Sichuan Province were used to establish the standard tree ring width chronology.The Miami model was used to reconstruct the climate-induced potential productivity of vegetation of 13 stations in Aba Prefecture from 1850 to 2010.It is found that the standardized chronologies have the potential to reflect past climate change and have good relationship with temperature determining productivity(M T)in Aba Prefecture.The M T in Aba Prefecture decreased from southeast to northwest,and first mode was consistent in the whole region,with the western and northern regions being large value zones.During the 100 years from 1850 to 1950,M T had no obvious change trend,but M T gradually decreased in the period from 1950 to 1980,and then increased rapidly until 2010.There were two mutations of M T in Aba Prefecture before and after 1967 and 1990,respectively,and M T had significant quasi-2-year cycle and 4-5-year cycle.These results show that it is an effective method to reconstruct climate-induced potential productivity of vegetation by using tree ring data.In the past 161 years,M T in Aba Prefecture had obvious spatial distribution differences and interannual and interdecadal fluctuations,especially since the 1980s,the increase rate and absolute value of M T had reached the maximum since 1850,which also provided evidence for global warming.