Extreme warm and cold waves derived from multiple high-resolution gridded datasets in Egypt

Abstract

The primary purpose of this study is to interpret the variability of extreme warm (Tmax) and cold (Tmin) events over Egypt from 1981 to 2020 using three gridded datasets that evaluated against the observations at 24 in situ stations using robust statistical procedures. These high-resolution gridded datasets are well-matched with the observed data. Furthermore, the monthly maximum of daily Tmax (TXx) and Tmin (TNx) and the monthly minimum of daily Tmax (TXn) and Tmin (TNn) climate indices are used to investigate the variability of extremes over Egypt. It is found that the TXx increased gradually throughout the study period and the Mann–Kendall rank correlation (Tau) is mostly positive in the first and last decades, with the coefficient of variation (COV) ranges from 1 to 5. Also, the lowest TXn values are detected in the first two decades with decadal anomaly ranging from − 2 to + 2, and it has positive Tau values during all decades with COV ranges from 2 to 20. The TNx increased southward, and its decadal anomaly increased gradually over time. The significant positive Tau of TNx is found in the first and last decades, and its COV ranges from 1 to 8. Moreover, the TNn is increased during the study period, and its anomaly is less than + 0.5 °C in the first decade and exceeds + 2 °C in the fourth decade. The significant positive (negative) Tau for TNn appeared during the third (fourth) decade, while its COV ranged from 1 to 12. Finally, the COV and Tau of all indices are often negatively correlated (> − 0.5).