Meteorological drought indices: Definitions

Abstract

Drought is part of nature’s climate variability recurring diachronically at a regional scale. Drought is considered as one of the major natural hazards having significant impact on several sectors of the economy, society, and environment. Drought is basically caused by the lack of precipitation events in a region over a period of time and can be regarded as an extreme climatic event. The early stages of accumulated precipitation deficiencies are referred to as meteorological drought being a region-specific natural event, since the atmospheric conditions that result in deficiencies of precipitation are highly variable from region to region. This chapter covers meteorological drought and its quantification through several drought indices. An attempt is undertaken to understand meteorological drought and explore several features through drought indices. There are many drought indicators and indices being used around the world. Indeed, the most commonly used drought indices are presented. Moreover, monitoring and assessment of meteorological droughts is also considered, along with significant drought impacts. The Standardized Precipitation Index is recommended by the World Meteorological Organization to be used universally, but it may not be accepted as the only and absolute index. Based on specific regional and climatic conditions, the use of other indices should also be taken into consideration. © 2017 by Taylor & Francis Group, LLC.