Drought assessment based on the number of days without precipitation

Abstract

When extreme and non-extreme physical events, such as drought, can affect elements of human systems in an adverse manner, it assumes the characteristic of a hazard. Droughts are the most complex but least understood of all natural hazards. It is broadly defined as a "severe water shortage". The objective of this paper was to investigate the number of days without precipitation during 30 years in chosen climatic stations in the eastern Slovakia. The results of the research proved that the occurrence of a drought in Slovakia is rare although periods longer than 30 days without precipitation were detected. This research may be helpful as one of the documents for water management practice, for example, for proposals of water harvesting in the country, the designing of other water structures or agricultural practices in the study area. The study of drought assessment is performed with the main goal of reducing negative impacts of droughts.

Analysis of the spatio-temporal propagation of drought over Eastern China using complex networks

“…represent the interval between two consecutive drought events in location l. is employed to represent a threshold of a maximum delay, which could exclude unreasonable long dynamic delays between the extreme events occurring at two locations. When and , it can be considered that the event i at location l and the event j at location m are synchronized, and i is ahead of j: (2) represents the relative number of drought events at l preceding event at m, which represents how likely an extreme event in location l can propagate to location m. is estimated as: (3) Where represents the total number of drought events at l. Similarly, is estimated as: (4) We repeat the above steps for each pair of grid points to derive a matrix of ES with the dimension of N×N (N represents the number of grid points).…”

“…Drought is considered by many to be the most complex but least understood of all natural hazards, affecting more people than any other hazard [1,2]. Affected by global climate change, meteorological and hydrological factors around the world are undergoing significant changes, and their changes have exceeded the natural fluctuations of the Earth itself, resulting in a significant increase in the frequency of drought events, deterioration in duration and severity.…”