How are types of drought distinguished?
Drought is not just lack of rain; it is a prolonged event defined by how water deficits spread from atmosphere into soil, rivers and society.
Formation process and geographic mechanism
Meteorological drought is below-normal precipitation; agricultural drought is insufficient root-zone moisture for crops. Hydrological drought appears later as rivers, lakes and groundwater decline. Socioeconomic drought arises when available supply cannot meet demand for services and production. These stages may begin at different times in the same region.
Spatial outcomes, measurement and management
Assessment combines precipitation, temperature, evaporative demand, soil moisture, snow, reservoirs and groundwater. One index cannot represent every sector. Early warning, water budgets, crop choice, leakage reduction and ecological flow plans are all needed. A short wet spell may not erase a long accumulated deficit.