Regional and Seasonal Differences in the Size and Maturity Spectra of Precipitation Systems with Lightning

Abstract:

In this study we explore the relationship of convective intensity to size and maturity, and particularly how this relationship differs throughout a variety of oceanic and continental regimes.

Using 16+ years of data from the Tropical Rainfall Measuring Mission (TRMM), and the radar precipitation feature (RPF) database therein, which comprises radar, passive microwave, and lightning observations of the tropics and extratropics from 36°S to 36°N, we selected 16 different geographic regimes that encompass a wide variety of terrain and ocean basins throughout 16 years and in each of the seasons.

We find that throughout the TRMM domain oceanic features with lightning tend overwhelmingly to be larger and more mature than land features with lightning. This relationship exists in varying extents throughout the global tropics. We focus on different regions and seasons to analyze the size and maturity spectra of electrified RPFs, not only in how these spectra are manifested in remotely sensed convective intensity proxies, but also in ERA-interim-derived environmental parameters.

We aim for a better answer to the question of what determines the degree of convective vigor sufficient for initiating lightning, and why this seems to vary in different meteorological regimes.