Lightning Topography - Diurnal Cycle

This section investigates how the pattern of lightning evolves over an average day.  All the images in this section are lightning topography maps, similar to those discussed elsewhere at this site, with the exception that each image only covers lightning for a single hour of the day.  The numbers plotted are still simply the totals of all strikes for July and August for the five years of 1995-1999, added up in 0.01 degree latitude by 0.01 degree longitude bins.  Again, this is approxiamately a 1 km resolution.  Separate images are made for all the strikes that occured from 1:00:00 PM to 1:59:59 and for all strikes that occured 2:00:00 PM to 2:59:59 and so on.  Putting these together yields an animation of the progression lightning pattern on the average.
The sample below covers the entire 72 quad region of study.  It does not cover the whole 24 hour period, but runs from 10:00 AM to 10:00 PM, which includes the most active part of the day.
The same color bar is used for all of the frames.   Each grid rectangle is close to 1 km by 1 km so a value of 10 means ten strikes in five years or about 2 strikes per square km per year.  This is a rather high value, considering that it only covers one hour of the day.  10 was not the highest value observed.  In the afternoon hours, over the mountains, values as high as 20 were seen.  However, using a color scale that runs from 0 - 20 would greatly fades the low end of the scale, where a lot of the data resides.  The grid locations with values over 10 are small in number and isolated so the choice was made to sacrifice discrimination at the very high end so that the low end has more contrast.  Any data point over 10 is also be plotted in black.
It should also be noted that the grid rectangles, which are 0.01 degree latitude by 0.01 degree longitude, are not all equal in area.  Therefore the colors are not quite proportional to lightning density.  This effect is fairly small however, amounting to about a 10% enhancement of the south end of the map relative to the north end.  This would for instance make a '7' at the top of the map correspond to the same lightning density as about an '8' at the bottom of the map, but it can be seen on the color bar that this is a fairly subtle difference.
The above animation shows important genesis areas for thunderstorms and some large scale general movement trends.  It also makes for a good comparison of the relative strength of any signal compared to other areas.  About 5 major areas stand out as active lightning regions.  These are highlighted on the image below, along with the average direction that motion/development occur.

Diurnal Animations and Frames Listing

Arizona Region:  [31 N - 37 N, 114 W - 108W]

Full 24 hour Animation   [1.74 Mb]