Based on WWLLN Data From 2008 to Present

These movies and plots were prepared by K. S. Virts working in collaboration with M. L. Hutchins, J. M. Wallace and R. H. Holzworth

Documentation of this work is in Virts et al. (2013)

Please send comments to kvirts@uw.edu or bobholz@uw.edu

Introduction

The ground-based World-Wide Lightning Location Network (WWLLN) continuously monitors global lightning. Below are links to lightning climatology maps and animations of its diurnal cycle, based on four years (2008-2011) of WWLLN data. For all maps, units are strokes km-2 yr-1; all months are included (unless otherwise specified); gray lines indicate the 500-m elevation contour; and the lightning scale is logarithmic. These animations report stroke densities as detected by WWLLN and are not corrected for relative detection efficiency. Comparisons between absolute intensities in different continental regions, using this work, could be misleading. However, regional patterns of diurnal variations are relatively insensitive to geographical variations in detection efficiency.

See also WWLLN sensor locations, with colors indicating when each station was established (note that some sensors were in place as early as 2004). Black stars indicate sensors added 2012-present.

Global and continental lightning maps (1 x 1 degree resolution)

First, an annual-mean map of global lightning that includes the full range of values of the frequency of occurrence of lightning and a corresponding elevation map (you may need to adjust the size of your internet browser to view the whole map). TRMM LIS/OTD also provides global lightning coverage , but WWLLN samples ~100 times as many strokes per year. The diurnal cycle of lightning can be illustrated by animations of hourly-mean lightning frequency. Limiting the color scale to the highest ~2 orders of magnitude brings out lightning enhancements near coastlines and mountain ranges: see the map and animation.

Continent-scale animations: North America, South America, Africa, Europe, Eastern Asia, Australasia, and northern high latitudes.

To directly compare the diurnal cycle from one region to another, see this animation of lightning frequency as a function of local time rather than UTC.

Regional lightning animations (0.25 x 0.25 degree resolution)

This section includes links to diurnal lightning animations for selected regions. For each region, time is expressed in UTC and as local time at some city (indicated by a star) within the domain. Favorites are marked with an *.

 

High-resolution regional lightning animations (0.1 x 0.1 degree resolution)

The diurnal cycle of lightning is particularly fascinating in regions with both coastlines and topography, where both land/sea breezes and mountain/valley breezes modulate the convection. Here are high-resolution hourly lightning animations for a few such regions. For each animation, local time is listed for some city (indicated by a star) in the domain. Favorites are marked with an *.

Acknowledgements

We thank the World Wide Lightning Location Network, a collaboration among over 50 universities and institutions, for providing the lightning location data used in these plots. The TRMM LIS/OTD climatology was obtained from NASA’s Global Hydrology and Climate Center. Coastline and elevation data were obtained from the National Geophysical Data Center.