Climatological variability of a thunderstorm environment dataset in tropical and temperate regions
Spatiotemporal variations in thunderstorm occurrence frequency are considered here using an environmental dataset derived from ERA5 reanalysis data. Interannual variability in the thunderstorm environments is examined for the period 1979-2023, with the standard deviation and coefficient of variation showing considerable spatial differences through the world. Atmospheric and oceanic modes of climate variability account for some of this interannual variability, particularly for the El Nino-Southern Oscillation through tropical and maritime regions, as well as to a lesser degree for the Indian Ocean Dipole, Arctic Oscillation and Antarctic Oscillation. Long-term trends can also contribute to interannual variability, with results showing increases are more common than decreases in the thunderstorm environments through the study region over the period 1979-2023. However, considerable uncertainties in those trends are noted as is also suggested from some additional analysis of global climate models, indicating that although more favorable thunderstorm environments might occur in a warming world, the estimated change over the period 1979-2023 is relatively small compared to the standard deviation in most locations. The study findings are intended to be complementary to other studies and contribute as part of a broader range of information available on thunderstorms and climate variability.