Methods of monitoring crop phonological stages using time series of vegetation indicator

Crop phonological stages monitoring is an important part of growth monitoring. Crop growth period has relation to not only weather variety, but also to the people's planting habit. Crop phonological stages and growth period vary in different years. The normalised different vegetation index (NDVI) derived from red band and near infrared band of SPOT vegetation sensor is the directly remote sensing indicator that reflects crop growth situation. Each main production county was used as a main research target. To eliminate the cloud effect, least square method and harmonic analysis method was used to reconstruct the time series of imagine. On the foundation that using 1∶100000 land cover mask the non-agricultural land, according to weighted average method, the information with crop growth profiles about the non-irrigated field and irrigated field crop was extracted. This combined with field measured data, and maximum rising slope, maximum value and maximum descending slope were used as remote sensing indications for different phonological stages during the corps growth period including emergence(recovering), heading and harvest for corps which harvest once each year. For corps which harvest more than once. At the same time taking the contrast among different years and analysed the effect of disaster on agriculture. The similarity coefficient of me results from remote sensing monitor emergence and harvest and from GVG photograph information was 90%, and bloom period reached 95%.It is the basis for processing crop classification, crop area change monitoring, crop yield forecast.