基于MODIS时序植被指数的陕西植被季相变化分析

分析了MODIS在植被生长变化监测中的优势,讨论了省级MODIS植被指数序列的建立方法。根据陕西主要植被覆盖类型,在风沙草原区、农作物区、林区共选取了5个样本县,利用2004-2005年MODIS-NDVI序列数据,通过提取NDVI曲线特征参数,结合地面气象观测资料,总结上述植被类型的季相变化特征,提出了关中农作物的物候变化规律和长势评价指标,探索了利用遥感手段对陕西省植被进行宏观、动态监测的方法。结果表明:风沙草原区植被对降水的依赖性很强,林区植被与温度的相关性较好,对降水的响应不明显。时序NDVI曲线是农作物生长的动态迹线,结合农作物的物候节律,可实时监测其生长状况并进行量化评价分析。

Analysis of Seasonal Dynamics of Vegetation Change in Shaanxi Province Based MODIS NDVI Time Series Data

The advantage of MODIS vegetation monitoring was analyzed. The methods for establishing time series of vegetation indicator by using MODIS data in Shaanxi Province were discussed. According to the main types of vegetation-cover in Shaanxi Province, five specimen counties were selected in desert steppe, cropland and forestland regions. The NDVI parameters of character curve by MODIS NDVI series data in 2004-2005 were distilled. The rule of crop phonological stages and indexes of growing evaluate, explore the method of vegetation dynamic monitoring in Shaanxi province by remote sensing method were put forward, combined with the meteorology observation data and the summarized seasonal dynamics change character in the desert steppe, cropland and forestland. Finally, the problems and improvements of the method were discussed. The results showed that a significant relation existed between desert steppe NDVI and monthly precipitation. In the forestland NDVI had relation to the monthly temperature, but less sensitive to the precipitation. Time series of NDVI profile could reflect the dynamics of crop growth and development. It could be used to monitor and assess the growth and development of crops combined with crop phonological stages.