Evaluation of CHIRPS in dry and wet spell assessment utilizing copula-based severity-duration-frequency curves

In situ rainfall data play a significant role in drought assessment studies. However, they are not available with reliable spatiotemporal coverage. With the advancements in satellite rainfall estimates (SREs), monitoring hydrological events in ungauged basins is possible. Additionally, the evaluation of newly released SREs such as CHIRPS, with a long-term record and comparably high resolution (0.05 & DEG;), in the assessment of extreme hydrological events (dry/wet spells) has scarcely been carried out, which is the most novel motivation of this study. Moreover, evaluation of CHIRPS in developing copula-based multivariate severity-duration-frequency curves based on the severity and duration of the occurred events in 1988-2019 over the Zayandehroud basin (a critical central basin of Iran), is innovatively appraised. An evaluation of CHIRPS in drought assessment shows its acceptable performance, with slight underestimation, in assessing the severity and duration of dry spells. In contrast, an overestimation is identified for wet spells.