The development of methods for correction of vegetation condition index VCI of ASIS FAO system

In ASIS FAO system the index of the condition of vegetation (VHI) calculated on the basis of the normalized differential vegetative index (NDVI) is used. ASI values can be used for the forecast of an agricultural crop by means of multiple-factor re-gression. Regression analysis between the yield (the quantity of a crop) and the VCI indexes (vege-tation condition index) and TCI (temperature condi-tion index) is for this purpose carried out and re-gression equation for the region is worked out. De-spite presentation of the data provided on the site Earth Observation, these data created on the basis of the VHI index have essential shortcoming con-sisting in not accounting of effect of saturation of the NDVI index at high maintenance of chlorophyll in plants. The purpose of conducted research is the development of the technique of updating the data provided on the site EARTH OBSERVATION, based on the basis of calculation of the index of the condition of vegetation of VCI of ASIS FAO sys-tem in relation to concrete regions of the world. In the study it is shown mathematically that the effect of saturation in the VCI index is shown more strongly, than in NDVI. The condition of excess of relative error of the VCI index because of saturation of corresponding relative error of NDVI index is in-vestigated. The method of logarithming, the capture of a derivative and the replacement of differential by increments is for this purpose used. It is shown that drawn conclusion is right both at zero, and at nonzero absolute error of NDVI saturation. On the basis of received results the recommendation of replacement of VHI index by earlier offered TCIM index is made. On the basis of conducted research the technique of updating of data of ASIS FAO sys-tem has been developed.