Seasonal variation of lightning on the Tibetan plateau: A spring anomaly?

Satellite observations of lightning over the Tibetan Plateau show a maximum flash density in July. Thermodynamic parameters and rainfall obtained from meteorological reanalysis are broadly consistent with the observed seasonal cycle. However, there is more lightning in Spring than one may expect from a simple relationship with rainfall, temperature or cloud buoyancy. The surface total heat flux best accounts for the seasonal variation of lightning including the Spring lightning. The cloud buoyancy and rainfall show a better seasonal relationship when they are multiplied by the ratio of the sensible to latent heat flux ( the Bowen ratio). This suggests an important role, at least in the Tibetan Plateau, for the sensible heat flux in modifying the efficiency of generating lightning from cloud buoyancy.