Storm characterization in the Canary Islands

Abstract

This is a study of the convective activity in an area surrounding the Canary Islands. These islands are under the influence of the Azores High Pressure Centre, which sends the Trade Winds from the Northeast. The result is a prevalence of atmospheric stability. However, polar fronts and tropical disturbances also affect the islands. These episodes can leave important amounts of rainfall and sometimes lightning. There are registers that show very severe episodes of this kind. Some authors have studied the relationship of the weather in the Canary Islands with teleconnection patterns (García Herrera et al., 2001). Regarding precipitation, it seems that some patterns affect the islands, but probably the most important factors are very local scale phenomena, enhanced by the complex orography of the islands. Regarding lightning activity, the intensity of the perturbation seems to be the leading factor. To the best of our knowledge, this is the first study of convective environments around the Canary Islands. Data from the highly valued ERA5 reanalysis from 1979 to 2021, in combination with lightning observations from 2007, are used. The study includes correlations between significant variables for convection, time series analysis of these variables, two lightning episodes, seasonal and diurnal variability of relevant variables. In addition, we have also studied the relation of these variables with teleconnection patterns (atmospheric circulation indices).