Developing a composite indicator with landsat thematic mapper/enhanced thematic mapper plus images for drought assessment in a coastal urban region

The occurrence of historical droughts led to studies on their impact and assessment methods. Droughts differ from most natural hazards in several important ways: (1) a slow-onset, creeping phenomenon occurs; (2) duration varies from event to event; (3) there is no universal definition; (4) no single drought index can identify precisely the onset and severity of the event; (5) spatial extent can be much greater than that of other natural hazards, making assessment difficult; (6) the core area or epicenter can change over time, reinforcing the need for continuous monitoring; and (7) impacts are generally difficult to quantify with cumulative effects. In particular, monitoring these phenomena in a fast-growing urban region where the multitemporal changes of land use and land cover (LULC) can affect holistic drought assessment is a challenge (Tadesse et al. 2005).