近15年来青海湖流域气温、降水变化对植被物候驱动分析

研究气候变化对植被物候的驱动分析,对于深入理解高寒植被适应全球气候变化具有重要意义。选取MCD12Q2植被物候数据,利用相关分析和GIS空间分析,对近15年来青海湖流域气温、降水变化与植被物候关系进行了研究。结果表明:近15年来青海湖流域植被返青期(start of growing season,SOS)、植被生长期长度(Length of growing season,LOS)、休眠期(Dormancy of growing season,DOS)与年均气温呈显著相关关系,其偏相关系数分别为-0.57～0.36,-0.89～0.81和-0.29～0.51; 与年均降水量偏相关系数分别为-0.58～0.38,-0.82～0.93和-0.23～0.23,表明流域植被SOS和LOS变化主要受年均气温和降水量共同影响,DOS变化主要受年均气温影响。青海湖流域植被SOS,LOS和DOS在空间上受气温、降水及其共同驱动的区域占比分别为33.7%,22.5%和36.67%,其受非气温—降水驱动的区域占比分别为66.3%,77.5%和63.33%; 沿海拔梯度方向上(海拔每上升100 m),年均气温上升1℃,植被SOS提前0.35 d,植被LOS延长0.15 d,植被DOS推迟0.25 d; 年均降水量增加1 mm,植被SOS推迟4 d,植被LOS缩短1.69 d; 植被DOS提前2.85 d。可见,近15年气温、降水变化对青海湖流域植被物候的驱动在空间上存在差异性,空间上植被物候主要受非气温—降水影响,海拔梯度上植被物候受气温和降水影响显著。

Analysis on the Drive of Temperature and Precipitation Changes to Vegetation Phenology of the Qinghai Lake Basin in the Past 15 Years

Analysis of drive of climate change on vegetation phenology is of great significance for in-depth understanding of the adaptation of alpine vegetation to global climate change.We used MCD12Q2 vegetation phenology data,correlation analysis method and GIS spatial analysis method to study the relationship between temperature and precipitation changes and vegetation phenology in the Qinghai Lake Basin in the past 15 years.The results showed that in the past 15 years,the annual average temperature in the Qinghai Lake Basin had a significant correlation with the start of growing season(SOS),the length of growing season(LOS),and the dormancy of growing season(DOS);the partial correlation coefficients were 0.36~0.57,-0.89~0.81 and-0.29~0.51,respectively;the partial correlation coefficients with the average annual precipitation were-0.58~0.38,-0.82~0.93 and-0.23~0.23,respectively;SOS and LOS of the vegetation in the Qinghai Lake Basin were mainly affected by the combined effect of the annual average temperature and precipitation,while the DOS was affected by the annual average temperature;in the past 15 years,SOS,LOS and DOS of the vegetation in the Qinghai Lake Basin were mainly driven by temperature andprecipitation,the proportions of the regions driven by temperature,precipitation and their combination were 33.7%,22.5%and 36.67%,respectively,the proportions of the regions driven by non-temperature-precipitation were 66.3%,77.5%and 63.33%,respectively;along the altitude gradient,the vegetation phenology was mainly affected by temperature and precipitation,the annual average temperature rose by 1℃,the vegetation SOS was advanced by 0.35 day,and the vegetation LOS was extended by 0.15 day;the average annual precipitation increased by 1 mm,the vegetation SOS was delayed by 4 days,the vegetation LOS was shortened by 1.69 days,and the vegetation DOS was advanced by 2.85 days.The drives of changes in temperature and precipitation to vegetation phenology in the Qinghai Lake Basin in the past 15 years had the spatial differences.The vegetation phenology in space was mainly affected by non-temperature precipitation,and the vegetation phenology along the altitude gradient was significantly affected by temperature and precipitation.