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Location-specific Lightning Alert Webpage

User Guide

Points to Note:

  • An alert message is given on the top left of the image specially for cloud-to-ground lightning. Users can select their own location of interest and up to 3 alert ranges under the "Set alert option". A message will pop up on the display whenever lightning is detected in the past 5 minutes in the specified ranges. The alert region can also be one of the four system-predefined regions (Click here to view the predefined regions). Also, when "Area Statistics" is selected, the number of lightning strokes detected within the area dragged by the mouse will be calculated.

  • A number of geographical reference overlays can be added to the lightning location map. These overlays include landmarks, swimming pools, peaks of Hong Kong, and municipal names of the Guangdong province (Map information of Hong Kong is provided by the Lands Department of Hong Kong and the Guangdong municipal information is provided by the Guangdong Meteorological Bureau). These references will be displayed only when the scale of the map is suitably chosen. For example, landmarks of Hong Kong will be displayed only when the proportion of the Hong Kong territory in the map is sufficiently large. Similarly, municipal names of Guangdong will be shown only when the map is selected to cover part of the Guangdong province.

  • This webpage can be selected to display radar images overlaid with lightning location information. The images were taken at 12-minute intervals and the rainfall rates estimated from radar data are represented by different colours. Since the measurements of radar and lightning location system differ in both time and space, the location of lightning may not correlate exactly with that of rain area in the radar image. For details about the radar images, please refer to the main pages of Weather Radar Image.



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Last revision date: <20 Dec 2012>