抄録
This paper describes a new method to remove high frequency fluctuations in timeseries normalized difference vegetation index (NDVI) of NOAA AVHRR. Time series NDVI of AVHRR are frequently used for global or continental land cover monitoring. However, NDVI values have undesirable noises due to cloud or atmospheric effect and signal noises. These effects cause high frequency fluctuations in time series NDVI. In order to remove these fluctuations, several methods such as Maximum Value Composite (MVC) method, Cloud screening method, J. Cihlar's method, and Maximum Value Interpolated (MVI) method have been developed. Since none of them provides satisfactory result, authors developed a new method, the Temporal Window Operation (TWO) method, main part of which is the removal of the effect of clouds to make a smooth temporal NDVI change. The TWO method also includes the removal of high value noises.
