Detection and Attribution of Norwegian Annual Precipitation Variability Related to Teleconnections

Detection and attribution of precipitation variability are fundamentally challenging, especially in the presence of complex nonlinear relationships between precipitation variability and large-scale teleconnections. The aim of this study is twofold. First, we identify abrupt changes and the trend and periodicity characteristics of long-term (1950-2019) annual precipitation series over the Norway mainland by using the Multiple Comparison Procedures, the Mann-Kendall test, and the Wavelet Analysis. Second, we interpret the variability characteristics found over five regions of Norway by exploring their relationships with teleconnections through the Maximal Information Coefficient. The results indicate that significant abrupt changes appeared in the mean (variance) value of annual precipitation series at 117 (49) out of 159 rainfall stations of five regions in Norway at a significance level of 0.05. The occurrences of change points varied from 1979 to 1984 in five regions of Norway. The mean and variance of the annual precipitation series increased by 32% and 16% at most, respectively, compared with those values before the change points. The first periodicity (spanning four to five decades) was the dominant periodic component and could be used to best characterize the Norwegian precipitation variability. Because the subtropical Azores High (subpolar Icelandic Low) moves toward (away from) Europe, the relationship between the annual precipitation series and the Scandinavian pattern (Atlantic Multidecadal Oscillation) series tended to be of an upward (downward) hook structure. The association of precipitation variability and teleconnections found in this study can pave the way for new possibilities with regard to detection and attribution of precipitation variability.

Automated summary

This study investigates abrupt changes, trends, and periodicity characteristics of long-term annual precipitation series in Norway using various statistical methods. The study also explores the relationships between precipitation variability and large-scale teleconnections. The findings suggest significant abrupt changes in precipitation series at multiple stations in Norway, and the dominant periodic component spans four to five decades. The study provides insights into the detection and attribution of precipitation variability.