Climatological Study of SPEI Drought Index Using Observed and CRU Gridded Dataset over Ethiopia

Abstract

This study aims to investigate the standardized precipitation evapotranspiration index (SPEI) using the monthly observed and gridded Climate Research Unit (CRU) dataset across 13 stations in Ethiopia during the period 1970–2005. SPEI is computed at a 4-month timescale to represent drought during the Belg (February–May) and Kirmet (June–September) seasons separately, and at an 8-month timescale to represent the drought during these two seasons together (February–September). The results show that there are extremely strong correlations (R ≥ 0.8) between the estimated precipitation values from CRU and the observed values, with root mean square error (RMSE) of 4–99 mm and mean percentage error (MPE%) of −30 to 73% at most stations. For temperature and SPEI, the CRU shows almost strong correlations (0.6 ≤ R < 0.8), while the dominant values of RMSE and MPE are 0.7–5 °C and −22 to 26%, respectively, for temperature and 0.28–0.96 and −49 to 55%, respectively, for SPEI during the three seasons. It is also found that each of the SPEI clusters (dry, normal, and wet) estimated from CRU has a high success percentage (≥ 60%) at more than 50% of the stations, while the general accuracy exceeds 60% for the three SPEI clusters together at more than 75% of the stations. Finally, the correct hits for the estimated SPEI clusters from CRU are often within the corresponding observed cluster but may shift into another category (extreme, severe, and moderate) except for a few events.

Future dry-wet climatic characteristics and drought trends over arid Central Asia

“…Frontiers in Earth Science frontiersin.org and evapotranspiration in a certain time range. The index not only considers the sensitivity of evapotranspiration to temperature, but also has the advantages of being suitable for multi-scale and multi-space comparison and high accuracy, which makes it an ideal index for drought research under the background of global warming (Musei et al, 2021;Morsy et al, 2022). In general, three calculation methods are used for potential evapotranspiration, including Thornthwaite, Penman-Monteith (P-M) and Hargreaves.…”

Investigating Whether the Ensemble Average of Multi-Global-Climate-Models Can Necessarily Better Project Seasonal Drought Conditions in China

“…Similarly, the same method was applied to obtain a new projection dataset using all five models, which is referred to as ENS-CGMMN hereafter. To uniform the spatial resolution of all GCMs and ENS-CGMMN, all of them were resampled to be 0.5 × 0.5 • by using the nearest neighbor remapping algorithm from the Climate Data Operators (CDO) package, which can maintain total precipitation to a desired degree of accuracy [73] and has been employed in many related studies [74][75][76][77]. Like CPAP, the GCMs and ENS-CGMMN were also aggregated into monthly total precipitation by summing monthly precipitation in each season of every year during 1961-2100.…”

Validação da SPEIbase para a Região Sudeste Brasileira

“…A seca meteorológica é um indicador de deficiência na precipitação, enquanto que as secas agrícolas e hidrológicas são causadas, respectivamente, pelo déficit hídrico no solo e deficiência nas vazões (Fontão et al, 2022;Morsy et al, 2022). Já a seca socioeconômica é uma crise que ocorre quando problemas sociais, econômicos e ambientais são decorrentes da falta de recursos hídricos (Fernandes et al, 2021).…”

“…Fernandes et al (2021) destacam que os impactos dos eventos de seca em diferentes setores estão relacionados a sua duração e o grau de severidade, além da sua frequência de ocorrência. Ou seja, o fenômeno torna-se consequência da associação dos tipos de secas mencionados anteriormente (Gonçalves et al, 2021;Morsy et al, 2022).…”

“…Os eventos de seca afetam todos os setores socioeconômicos, com destaque para o setor agrícola, altamente dependente das condições climáticas (Santos et al, 2011;Cunha et al, 2019). A variabilidade e as mudanças climáticas podem incrementar a frequência e intensidade das secas Morsy et al, 2022;Sobral et al, 2019;Raposo et al, 2023). A compreensão dos motivos de ocorrência e impactos provocados por esses eventos é fundamental para o desenvolvimento de estratégias eficazes de planejamento, mitigação e adaptação (He et al, 2023), principalmente por parte dos gestores de políticas públicas e privadas, a fim de auxiliar na tomada de decisões (Gonçalves et al, 2021;Arra et al, 2023).…”