During the period from 1995 to 2010, flooding and drought occurred
frequently in North Korea. This greatly affected agriculture. The precipitation data
was the main factor evaluated in flood and drought monitoring. In this study, the Z
index method was used to estimate the change in precipitation, calculated from
TRMM (Tropical Rainfall Measuring Mission) data. The Z index and the NDVI were
combined with the map of distribution of rice to analyze the relationship between the
Z index and NDVI during the growing months of rice in recent 12 years. The results
revealed that the Z index is a good indicator to study the relative changes of
precipitation in North Korea, and that the relationship between the Z index and NDVI
in a quadratic function.