Relationships Between Total Lightning and Tropical Cyclone Intensity Change Observed TRMM Lis

Previous studies suggested that lightning activity could be an indicator of Tropical Cyclone (TC) intensity change but their relationships vary greatly and at times appear contradictory. To date, most TC lightning studies have been based on measurements from the NLDN, WWLLN, and similar ground-based networks. While NLDN observes total lightning within a few hundred kilometers of land, WWLLN detects only a small fraction of the TC lightning, mostly CG lightning, yet provides near global coverage. Several studies have shown the importance of total lightning for TC intensification study and forecasting applications. Our research leverages the 16-yr total lightning data recorded by TRMM LIS to investigate TC total lightning characteristics, lightning-TC intensity change relationships, and relations between TC total lightning and environmental factors. Our results show that decreased (elevated) total lightning density in the inner core (outer rainband) are observed +24h prior to TC intensification, consistent with the CG lightning patterns reported by recent statistical studies using WWLLN data (DeMaria et al. 2012). Similar relationships between 30 dBZ echo volume (an indicator of intense convection) and +24h TC intensity change are also found. However, convective depth, as indicated by 20 dBZ echo-top height and IR brightness temperature, show a positive relationship to +24h TC intensity change. On the other hand, both lightning density and convective depth increase substantially following (-24 h) TC intensification, suggesting vigorous convection with lightning may be a response to TC intensification more than a leading signal as proposed by previous researchers. Our statistics also suggests that the negative relationship between lightning density and +24h TC intensity change stays the same when TCs are categorized by prior (-24h) intensity change. We will further investigate why lightning and 30 dBZ echo volume exhibit an opposite relationship with TC intensity change compared to deep convective towers (tall 20 dBZ echo-top).