A Method to Estimated Winter Wheat Yield with the MERIS Data

The MERIS data will provide us time-serial parameters, with which we can get the information that describe the growth process of winter wheat, so inputted these information into a biomass model with the real time meteorological data, and then we could get the biomass of winter wheat. For calculating the yield of winter wheat, the harvest index (HI) must be estimated. There were very rarely people to estimated HI of crop with the remote sensing data. Based on the own character of winter wheat, we found that the correlation between HI and the ratio of NDVIpre (the average value of NDVI form emergence to anthesis) and NDVIpost (the average value of NDVI from anthesis to maturity) is quite well. Therefore, with the NDVI calculated from remote sensing data, we can estimate the HI of winter wheat for every pixel. Finally, we can use the follow expression to calculate the yield of winter wheat, YIELD = BIOMASS x HI, and HI = f(NDVI). With this method to estimate the yield of winter wheat, the temporal and spacial information of MERIS data has been used adequately. And the precision of the yield of winter wheat estimated with this method is better than that with a fixed HI. Because of the advantage and objectivity of the remote sensing data, this method is very useful and adequate for estimating the yield of winter wheat in daily operation.