Fig. 5: Conceptual model for the illustration of NBEs polarity transition in thunderclouds with OT.
From: Polarity transitions of narrow bipolar events in thundercloud tops reaching the lower stratosphere
a A normally electrified thundercloud with the upper positive charge of ice crystals and the main negative charge of graupels. b The required charge distribution for the dominant positive NBEs during the upwelling stage with strong convection of OT. Positive NBEs outbreak inside the cloud between the middle negative charge layer and the upper positive charge layer. The size of the red arrow represents the strength of the updraft while the blue arrow represents the downdraft. c The required charge condition for the outbreak of negative NBEs during the decaying stage of OT. Negative NBE discharge initiates in the upper region of the cloud between the upper positive and negative screen charge layer.
