Assuming this is cloud-to-ground strike data...
http://www.stats.govt.nz/browse_for_sta ... tning.aspxOn average, the New Zealand region (land and approximately 500 kilometres out to sea) receives around 190,000 ground and sea lightning strikes a year, with nearly one-quarter (around 45,000 a year) occurring as ground strikes.
*In 2014, the New Zealand region had 136,278 ground and sea lightning strikes.
*From September 2000 to December 2014:*The national total number of lightning strikes per month did not show a determinable trend, and none of the 15 regions (Nelson and Tasman were combined) showed a determinable trend.
- parts of the West Coast in the South Island had the highest annual average and density of ground strikes, at 9–36 per 25km2
parts of northern Taranaki, Waikato, and Bay of Plenty regions were prone to lightning, with an annual average of 6–36 ground strikes per 25km2 in some areas.
Definition and methodology
Lightning is the discharge of electricity from thunderstorms that equalises areas of positive and negative charge, for example, between a storm cloud and the ground. Thunderstorms form as a result of rapidly rising air with high moisture content (humidity). On average, 1 in 10 lightning discharges strike the ground (or sea) (MetService, nd). Lightning (and therefore thunderstorms) is often associated with other severe weather events, such as strong wind gusts, and in extreme cases, tornadoes.
The New Zealand Lightning Detection Network (NZLDN) run by Transpower and MetService records the number of lightning ground strikes. Sensors around the country detect lightning over the New Zealand land mass and a short distance out to sea (approximately 500km). These sensors detect very accurately the electrical discharge, location, time, and other parameters, such as current strength. The NZLDN records both cloud-to-cloud and cloud-to-ground strikes. Generally, the location of cloud-to-ground strikes can be determined to within approximately 1km.
By international standards, lightning does not occur frequently around New Zealand. However, thunderstorms, and as a result lightning, can cause injury and damage (Ministry of Civil Defence and Emergency Management, 2010), and may be more frequent and intense with climate change (Mullan et al, 2011).
