Meteorological drought analysis using copula theory and drought indicators under climate change scenarios (RCP)

Abstract

The study was carried out to assess meteorological drought on the basis of the standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) evaluated in future climate scenarios. Yazd province, located in an arid region in the centre of Iran, was chosen for analysis. The study area has just one synoptic station with a long‐term record (56 years). The impact of climate change on future drought was examined by using the CanESM2 of the CMIP5 model under three scenarios, that is, representative concentration pathways RCP2.6, RCP4.5 and RCP8.5. Given that a drought is defined by several dependent variables, the evaluation of this phenomenon should be based on a multivariate analysis. For this purpose, two main characteristics of drought (severity and duration) were extracted by run theory in a past (1961–2016) and future (2017–2100) period based on the SPI and SPEI, and studied using copula theory. Three functions, that is, Frank, Gaussian and Gumbel copula, were selected to fit with drought severity and duration. The results of the bivariate analysis using copula showed that, according to both indicators, the study area will experience droughts with greater severity and duration in future as compared with the historical period, and the drought represented by the SPEI is more severe than that associated with the SPI. Also, drought simulated using the RCP8.5 scenario was more severe than when using the other two scenarios. Finally, droughts with a longer return period will become more frequent in future.

Drought Risk Analysis in the Eastern Cape Province of South Africa: The Copula Lens

“…In order to characterize drought, we have used the run theory proposed by [40,41]. For this study, we have considered the drought duration and severity as two main drought characteristics derived using the algorithm summarized as follows:…”

Comparison of the temporal distribution pattern of precipitation and the cumulative effect of daily droughts on the local scale in Iran

“…The run theory is a method for ordering the sequence of features of a process (Yevjevich 1967). This method defines and standardizes drought characteristics for use in various models (Chen et al 2011;Mesbahzadeh et al 2020) such as identification of events (Wu et al 2019), length (Moyé and Kapadia 1995), and severity of drought (Liu et al 2015;Bae et al 2018). The run theory was used to identify the frequency, severity, and duration of drought in the time series for this study.…”

Análisis temporal de sequías meteorológicas en la cuenca del Río Yaqui (México) y su relación con ENSO

“…La predicción de condiciones de sequía en el futuro es considerada un paso primordial para la prevención de daños (Mesbahzadeh et al, 2020), por ello, es indispensable analizar la variabilidad interanual de la precipitación, para detectar la presencia de eventos extremos tanto secos como húmedos, así como su recurrencia. Sin embargo, la determinación de las características de la sequía es muy difícil, dado que existe una variedad de índices para su evaluación (Heim, 2002).…”

“…Sin embargo, la determinación de las características de la sequía es muy difícil, dado que existe una variedad de índices para su evaluación (Heim, 2002). El SPI (McKee, Doesken & Kleist, 1993) es el indicador comúnmente usado para analizar la severidad, duración y frecuencia de las sequías meteorológicas (Mesbahzadeh, 2020) y ha permitido detectar, el inicio, fin, intensidad, duración y frecuencia de eventos extremos (sequías e inundaciones) en distintas regiones del Mundo (Heim, 2002;Velasco, 2006;Zucarelli, 2013;Raziei et al, 2014;Paredes, Barbosa & Guevara, 2015)…”