Increase in Lightning and Upper Tropospheric Water Vapour Over the Arctic Circle

Abstract

Sea ice in the Arctic grows during each hemisphere’s winter and it retreats in the summer. The highly reflective white surface of sea ice reflects solar energy, cooling the planet. When it melts, the darker ocean absorbs more heat, reinforcing the cycle of melting sea ice. Sea ice plays a critical role in regulating Earth’s climate, and it influences global weather patterns and ocean circulations. One essential feedback in the Arctic is the rise in upper tropospheric water vapor (UTWV) or the specific humidity (SH) that acts as an intense greenhouse gas trapping in additional heat released from the Earth's surface.   While temperature change is driven by increasing greenhouse gases, the interannual variability in sea ice can be explained by changes in the UTWV (ASO) at 400mb in the Arctic. Where is this increase in UTWV (400mb) coming from in the Arctic?  Thunderstorm activity appears to be increasing in the Arctic in the last decades, and could be a source of the increasing UTWV, and hence the decrease in Arctic sea ice.