Comparative evaluation of precipitation-temperature based drought indices (DIs): A case study of Moroccan Lower Sebou basin

Abstract

Due to the lack of studies on drought in the Lower Sebou basin (LSB), the complexity of drought event and the difference in climate conditions. The identification of the most appropriate drought indices (DIs) to assess drought conditions has become a priority. Therefore, assessing the performance of different drought indices was considered in order to identify the universal drought indices that are well adapted to the LSB. Based on data availability, five DIs were used: Standardized Precipitation Index (SPI), Standardized Precipitation and Evapotranspiration Index (SPEI), Reconnaissance Drought Index (RDI), self-calibrated Palmer Drought Severity Index (sc-PDSI) and Streamflow Drought Index (SDI). The DIs were calculated on an annual scale using monthly time series of precipitation, temperature and river flow from 1984-2016. Thornthwaite's method was used to calculate potential evapotranspiration (PET). Pearson's correlation (r) were analyzed. Furthermore, five decision criteria namely robustness, traceability, transparency, sophistication and scalability were used to evaluate the performance of these indices. The results proved the fact that SPI is suitable to detect the drought duration and intensity compared to other indices with high correlation coefficients especially in sub humid regions, knowing that it tends to give more results that are humid in stations with semi-arid climates. SPI, SPEI and RDI follow the same trend during the period studied. However, sc-PDSI appears to be the most sensitive to temperature and precipitation by overestimating the drought conditions. Eventually, the results of the performance evaluation criteria revealed that SPEI classified first (total score = 137) among other meteorological drought indices, followed by SPI, RDI and sc-PDSI.

Toward a Redefinition of Agricultural Drought Periods—A Case Study in a Mediterranean Semi-Arid Region

“…The years 2001, 2004, 2007, 2017, 2019, 2020, and 2021 stand out as the most severe drought periods. These results corroborate the observations of various authors, cited in several works across different regions of Morocco [46,[50][51][52], such as the Oum Er-Rbia river basin [53], northwest Morocco [54], the Sebou basin [55], and the Souss basin [56]. These regions, characterized by their semi-arid, arid, and Mediterranean climatic characteristics, have been the focus of previous research, which has also highlighted particularly dry years, in line with our findings.…”

Spatiotemporal evolution of droughts and their teleconnections with large-scale climatic indices in the Lower Sebou Basin in northwestern Morocco

“…The results reveal some differences between DIs in drought monitoring, found in most studies (Liu et al 2021;Hakam et al 2022a), which are due to the variation in climatic conditions at the different LSB stations and especially at the Zirara station (Figure 9). The fact that the calculation of DIs is based on rainfall and that the variability of rainfall is much higher than that of PET, considered stationary (without temporal trend), the importance of the latter would be negligible and drought conditions are almost controlled by the temporal variability of rainfall.…”

“…As a result, two drought indices can be used as a basis for characterizing meteorological drought in the LSB, the Standardized Precipitation Index (SPI) (McKee, Doesken and Kleist 1993) and the Standardized Precipitation-Evapotranspiration Index (SPEI) (Vicente-Serrano, Beguería and López-Moreno 2010). Widely used in the world (Vicente-Serrano et al 2012;Beguería et al 2014;Šebenik, Brilly and Šraj 2017) and recommended by the World Meteorological Organization (World Meteorological Organization 2012), these indices have been recently applied in the LSB due to their performance and regional applicability compared to other drought indices (Hakam et al 2022a). The SPI and SPEI approaches are similar, but there are obvious differences between the input parameters for the calculation.…”

“…More vulnerable than other basins, facing numerous droughts (Ajlal and Agoutime 2021;Hakam et al 2022a) and subject to a drought warning by the Regional Observatory of the Environment and Sustainable Development in Morocco (2014), the climatic study of the LSB has become paramount. As no regional…”

Determining the impacts of climate change on Spatio-temporal patterns of meteorological drought using SPI

“…Especially those in North Africa, were found to be the most affected by climate change which became the main cause of drought (Stringer et al, 2009;Hamed et al, 2018). Drought is among the world's costliest natural disasters (Hakam et al, 2022). It was monitored in Algeria and affected climatic conditions in the northwestern part, where the lowest precipitation rates were recorded at 100 mm/year (Medejerab and Henia, 2011;Meddi et al, 2013;Zeroual et al, 2019).…”