Variations in Global Lightning on Climate Time Scal

Previous appeal has been made to global lightning as an indicator of climate change for two main reasons: (1) lightning activity is demonstrably sensitive to temperature on short time scales (diurnal, semiannual, and annual), and (2) a natural framework is in place (the global electrical circuit and the Earth’s Schumann resonances) to monitor global lightning activity on a continuous basis.  This talk will focus on the use of several measures (Schumann resonances, optical measurements of lightning from space, lightning network observations and thunder day observations at meteorological stations) to examine variations in lightning on the annual time scale and longer to decadal time scales.  Evidence for long-term increases in local lightning activity in large urban areas (Sao Paulo, Brazil) and at high northern latitudes (Alaska, USA) will be shown.  Evidence for a regional flattening of trend in thunder days during the ‘stagnation’ in global temperature in the period 1940-1970 will also be shown.  In the most recent decade (2002-2013), the global warming trend has gone flat in multiple records (NASA GISS and NASA MSFC), and is consistent with flat behavior in the best long-term measure of global lightning flash rate (Lightning Imaging Sensor data on the TRMM satellite).  Two 20-year records of Schumann resonance observations (Hungary and Rhode Island, USA), recently organized and currently being scrutinized), will be discussed, including attention to the role of the 11-year solar cycle.

Earle Williams

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