Extreme precipitation trends in northeast Algeria using a high-resolution gridded daily dataset

This work presents a study of variability and trends of extreme precipitation events in northeast Algeria using a high-resolution gridded dataset. To this end, 10 extreme precipitation indices were computed over a daily gridded precipitation dataset with a spatial resolution of 1x1 km from 33 series of weather observatories, covering the period from 1970 to 2010. The processes involving the reconstruction of the missing data and gridding were applied based on the approach of creating reference values (RV), allowing for a comprehensive quality control of the original data while reporting and deleting suspicious values that do not correspond to the natural spatial and temporal distribution of daily precipitation. These RV were used to complete a reconstructed dataset without missing values, based on the cleaned data series. Then, it was used to create the high-resolution gridded dataset over northeast Algeria. In view of the obtained results, a general increasing gradient of the extreme precipitation indices from south to north was noted, particularly at the coast and at high-altitude regions. Furthermore, upward trends in extreme intensity and frequency precipitation indices, such as PRCPTOT, SDII, RX1day, RX5day, R10mm, R20mm, CWD, R95p, and R99p were observed, except for the consecutive thy days (CDD) index, which showed a remarkable decrease. However, most of the estimated trends were not statistically significant at .05 levels.