B1605
Title: Defining extreme droughts via run theory
Authors: Samira Aka - ESSEC-LSCE (France) [presenting]
Abstract: Droughts are complex phenomena that pose significant challenges to water resource management, agriculture, and energy production. Traditional drought indices, such as the standardized precipitation index (SPI), assume independent and identically distributed (i.i.d.) precipitation data and standardize this data as a normal distribution. However, when viewed as a binary sequence, precipitation occurrence is not normally distributed. Alternations between the occurrence and non-occurrence of rain can be analyzed as runs. Therefore, understanding the dependence between runs of precipitation occurrence is essential to capture the notion of persistence, which is lacking in traditional indices. Many papers have focused on extreme dry spell lengths using traditional continuous approaches. However, these methods are not suitable when considering sequences of binary outcomes. Various properties of dry spell lengths are derived within a Markovian framework. The new drought monitor is applied to daily Swiss precipitation data recorded by the University of Geneva from 105 stations during the period 1930 to 2014.
