Global drought and flood-watch from NOAA polar-orbiting satellites

Drought and flood are the most damaging environmental phenomena. In a quarter of the century since 1967, droughts affected sixty and floods thirty percent of 2.8 billion people who suffered from weather-related disasters. Moreover, they were a cause of 1.6 million deaths from the total number of 3.5 million people killed by all disasters during 1967-1991. Since drought and flood cover large areas, it is difficult to monitor them using conventional systems. In recent years, the National Oceanic and Atmospheric Administration (NOAA) has designed a new AVHRR-based indices that have shown to be useful for detection and monitoring large area vegetation stress resulted from drought or soil oversaturation following flooding and excessive rains. These indices are Vegetation Condition Index (VCI), Temperature Condition Index (TCI) and their combination (V/TCI). These indices showed their excellent ability to detect vegetation stress due to drought and soil oversaturation and are useful in measuring time of onset, intensity, duration, and impact on vegetation of these phenomenon. This paper shows the principals of VCI/TCI application.