摘要
植被绿度始期是研究植被生长周期与气候变化关系的一个重要参量。本文选取中国的青藏高原地区、中东部地区和东北地区作为研究区域,基于1983—2012年NOAA/AVHRR上的NDVI累积频率曲线,利用Logistic函数进行拟合计算植被的绿度始期,并结合MODIS Collection 5地表覆盖类型数据,分析了不同区域内不同类型植被绿度始期的变化特征及差异性。结果表明:草地、灌木林、落叶乔木林和农田类型的绿度始期总体呈现提前趋势;在同一区域内,不同类型植被的绿度始期出现的时间不同;在不同区域内,同一类型植被绿度始期的年际变化表现不同的趋势,草地的绿度始期总体呈现提前的趋势,青藏高原地区提前趋势明显,变化率达到6.11 d·10 a^(-1),中东部地区为5.37 d·10 a^(-1),东北地区为2.13 d·10 a^(-1);落叶乔木林的年际变化幅度大致和草地相似,随着纬度的升高和海拔的降低,其绿度始期的提前变化速率会逐渐变小,灌木和农田在东北出现了绿度始期的推迟趋势,多年延迟的变化率为1.49和1.03 d·10 a^(-1)。
The onset of greenness of vegetation is one of the important parameters to investigate the relationship between growth periodicity of vegetation and climate change. This study selected three areas including Tibetan Plateau,mid-eastern and northeast of China as typical research areas. Based on the cumulative frequency data of NDVI on NOAA / AVHRR in 1983—2012,Logistic fitting functional model was used to calculate the DOY（ days of year） of onset of greenness with MODIS Collection 5 land-cover data. The characteristics and differences of the onset of greenness with different vegetations in different areas were analyzed. The results showed that the onset of greenness by different vegetations of grasslands,shrub,deciduous tree and cropland generally presented a trend in advance. The different types of vegetation had different onsets of greenness in the same area. The inter-annual variability of the onset of greenness by the same vegetation types showed different trends in the different areas. The onset of greenness of grassland in the Tibetan Plateau changed at a rate of 6.11 d·10 a^（-1）in advance,5.37 d·10 a^（-1）in the mid-eastern regions in China,and 2. 13 d · 10 a^（-1）in the northeast of China. The amplitude of inter-annual change of deciduous trees was roughly similar to that of the grassland. The changing rate of onset of greenness in advance would gradually be smaller with the increase of latitude and the decrease of altitude. The onset of greenness of the vegetation types of shrubs and cropland in northeast China appeared a delaying trend,with respective delaying rates of 1.49 and 1.03 d·10 a^（-1）.
出处
《生态学杂志》
CAS
CSCD
北大核心
2016年第6期1617-1626,共10页
Chinese Journal of Ecology
基金
国家自然科学基金项目(41575110)
国家自然科学基金委员会-广东省人民政府联合基金(第二期)超级计算科学应用研究专项(nsfc2015_233)资助
