21世纪初中国农作物与自然植被物候时空差异

利用离散小波方法对2001~2012年MODIS EVI时序数据进行平滑,基于动态阈值法提取我国植被物候信息,探讨农作物和自然植被物候的时空变化特征。结果表明:(1)我国第一季农作物开始、峰值和结束日期主要以华北平原为中心随海拔的上升而推迟,而自然植被物候更早20d左右,且随海拔的上升先推迟后提前;(2)物候在时序上有显著变化的第一季区域,43.98%开始日期、52.83%峰值日期呈现提前趋势,多在开始晚、结束早的西南区及东北与内蒙古交界处,其余区域开始、峰值日期及81.80%结束日期呈推迟趋势,发生在开始早、结束晚的黄土高原及双季农作区;农作物物候推迟幅度小于自然植被。

Spatio-temporal Difference of Crops and Natural Vegetation Phenology in China at the Beginning of the 21st Century

A smoothing algorithm based on discrete wavelet was firstly applied to the MODIS EVI time\|series data from 2001 to 2012 to minimize the effects of anomalous values caused by atmospheric haze and cloud contamination,based on dynamic threshold method to extract vegetation phenology information of China,study the spatio\|temporal variation characteristics of crops and natural vegetation phenology,The results indicate:①In the first season of crops,start date,peak date and end date mainly with altitude rise delayed centred on north China Natural vegetation phenology advance than crops about 20 days,As the rise of the altitude to delay first,and then in advance;②In temporal,Phenological have significant changes area of the first quarter,43.98% of start date,52.83% of peak date have trends in advance,Mainly in southwest,the junction of the northeast and Inner Mongolia,where the start date later and end date early.The rest of the region,start date,peak date and 81.80% of end date showed a trend of delay,Mainly in Loess Plateau and double season crop area;Crop phenological delay rate is less than natural vegetation.