LAROUCHE, Santa – 2003

Lightning climatology for the Maritime Provinces using the Canadian Lightning Detection Network 1998-2001

A lightning climatology for the Maritime Provinces of New Brunswick, Prince Edward Island, and Nova Scotia, including surrounding waters has been produced. As well, a focus on lightning activity within a 25 nautical mile radius of selected regional airports is presented. The physical characteristics and geographical distributions of over 600 thousand flashes from January 1998 through December 2001 using data from the Canadian Lightning Detection Network are examined and the results provided. Documentation includes annual and seasonal lightening flash counts, latitudinal variations, and diurnal distributions. Physical characteristics examined include positive and negative polarity distributions, percent positive polarity, media peak currents, and multiplicity. Seasonal flash density maps produced using a GIS are also analysed and presented. Dominant and recurring warm season patterns are evaluated in detail.

Overall, lightning activity for the study area has decreased since 1998. Maximum density values are found in northwestern New Brunswick, while the lowest densities are located over the Cape Breton Highlands and inland of Nova Scotia’s south shore. Winter months have high percentages of positive lightning occurring. In contrast, warm season analysis depicts an increase in positive lightning as the numbers of negative lightning decrease.

A few intense lightning events dominate the average values for the climatology, although results agree well with previous studies. As data becomes available, a more stable or smooth climate description may be provided.