基于MODIS-NDVI的浙江省耕地复种指数监测

The Monitoring for Sequential Cropping Index of Arable Land in Zhejiang Province Using MODIS-NDVI

【目的】耕地复种指数是重要的农情信息,本文旨在运用遥感数据对于这一参数进行监测与分析,为指导农业生产提供参考。【方法】采用美国国家航空和宇宙航行局(NationalAeronauticsandSpaceAdministration,NASA)提供的中分辨率成像光谱仪(moderateresolutionimaginespectroradimeter,MODIS)植被数据,利用1﹕25万浙江省土地利用现状图,设计二次差分的算法,对浙江省连续4年(2001～2004)耕地复种指数进行监测;【结果】一年内农作物播种、出苗、抽穗、成熟及收获等物理生长过程,反映在归一化植被指数(normalizeddifferencevegetationindex,NDVI)时间曲线上呈现出波动变化,其波峰所对应的是农作物群体生物量最大的时相。根据此原理通过提取耕地NDVI在一年内时间序列峰值频数,得出浙江省市级耕地的复种指数。【结论】浙江省耕地复种指数在空间分布上表现为西南大于东北。在时间上,从2001年到2003年有降低的趋势;而2004年有所增加。但相对于浙江的地理位置与气候条件来说,复种指数普遍偏低,潜力很大。

[ Objective ] The sequential cropping index of arable land is an important agricultural information, the objective of this paper is that monitor and analyze this parameter, and supply a reference for guiding agricultural production. [Method] Based on the MODIS （moderate resolution imagine spectroradimeter） vegetation data from NASA（National Aeronautic and Space Administration） in America and the actual land use map with a scale of 1 ： 2 500 000, using two times differencing, this paper monitors the cropping index of arable land in Zhejiang Province from 2001 to 2004. [Result] Within one year, there are principles of the interaction between the time series of NDVI （normalized difference vegetation index） profile and the growing process of crops, this process can be described as planting, seeding, heading, ripe, harvest and so on, and the peak of the time series of NDVI profile indicates that the colony ground biomass reaches the tiptop, so sequential cropping index can deem that equal to the number of peaks of time series of NDVI profile. Based on this principle, the sequential cropping index of all cities in Zhejiang Province was worked out. [ Conclusion] It was found that the sequential cropping index in southwest is bigger than northeast in Zhejiang Province in the space. In the time, the sequential cropping index shows the depressed levels from 2001 to 2003 and the value increaseed to some extent in 2004, but the value was low, so there are much potential for the sequential cropping index of arable land in Zhejiang Province in consideration of the geography and the climate in Zhejiang Province.