基于MCD12Q2的秦岭植被物候时空变化及对气候的响应

Spatiotemporal Variation of Vegetation Phenology and Its Response to Climate in Qinling Mountains Based on MCD12Q2

植被物候是反映环境条件和气候变化最客观、最敏感的指示器,秦岭是中国南北自然环境的分界线,研究秦岭物候变化对于深入理解和预测陆地生态系统的动态变化具有重要的意义。基于2001-2016年连续16 a的MCD12Q2数据和气候资料、利用统计分析方法对秦岭地区植被物候变化规律及对气候的响应进行了研究,结果表明,(1)秦岭地区植被物候始期、末期、生长期长度大体呈现由南到北的纬向分异规律。物候始期表现出由南向北逐渐延迟的纬向分布特征,物候末期分布情况与始期大体相反。生长季始期主要分布在第80—110天(3月下旬至4月中旬),生长季末期均值集中分布在第300—320天(10月下旬至11月中旬),生长期长度绝大部分在200-240 d之间。(2)16 a间秦岭地区植被物候年际变化的总体特征呈现生长始期具有提前趋势(P>0.05),平均提早0.61 d·(10 a)^−1;生长末期具有显著的推迟趋势(P<0.05),平均推迟3.1 d·(10 a)^−1;生长期长度年际变化具有延长趋势(P>0.05),平均延长3.7 d·(10 a)^−1。(3)生长始期随海拔高度呈现上升线性提前,海拔每升高1000 m,生长始期推迟18 d左右。(4)秦岭地区植被生长始期与3月气温之间具有极显著的相关关系(P<0.01),3月气温每增加1℃生长始期提前2.1 d;生长末期与9月气温之间具有显著的相关关系(P<0.05),9月气温每增加1℃生长始期推迟1.5 d。研究结果揭示了秦岭地区植被物候及其变化趋势、变化速率的时空分布特征,分析说明了物候的变化与春、秋季温度密切相关。

Vegetation phenology is the most objective and sensitive indicator to reflect environmental conditions and climate change.Qinling is the boundary of natural environment between North and South China.It is of great significance to study the phenology change of Qinling for further understanding and predicting the dynamic change of terrestrial ecosystem.Based on the 16 years of MCD12Q2 data and climate data from 2001 to 2016,this paper studies the changes of vegetation phenology and its response to climate in Qinling region by using statistical analysis method.The results show that:(1)The length of vegetation phenology in the beginning,end and growth period in Qinling region presents the latitudinal differentiation from south to north.The distribution of phenology in the late stage is opposite to that in the beginning stage.The beginning of the growing season is mainly from the 80th to the 110th day(from the last ten days of March to the middle of April),the average value of the end of the growing season is mainly from the 300th to the 320th day(from the last ten days of October to the middle of November),and most of the growing period is from the 200th to the 240th day.(2)During the past 16 years,the annual change of vegetation phenology in Qinling area showed an early growth period(P>0.05),with an average of 0.61 d·(10 a)^−1;a significant late growth period(P<0.05),with an average of 3.1 d·(10 a)^−1;the annual change of the length of the growth period showed an extended trend(P>0.05),with an average of 3.7 d·(10 a)^−1.(3)The beginning of growth is linear advance with the rise of altitude.For every 1000 m elevation,the beginning of growth is delayed for about 18 days.And(4)there was a very significant correlation between the beginning of vegetation growth and the temperature in March(P<0.01),the beginning of vegetation growth was 2.1 days ahead of the time when the temperature increased by 1℃;there was a significant correlation between the end of vegetation growth and the temperature in September(P<0.05),and the beginning of vegetation growth was 1.5 days behind the time when the temperature increased by 1℃.The results reveal the temporal and spatial distribution characteristics of vegetation phenology,its change trend and change rate in Qinling area.The analysis shows that the change of phenology is closely related to spring and autumn temperature.