Diagnosing the evolution of a thunderstorm during the CHUVA/GO-Amazon Field Campaign

During September of 2014 two field campaigns named CHUVA and GO-Amazon conducted a series measurements in the Amazon region to explore the effect of aerosols in the precipitation. To further understand the role of aerosols in the development of thunderstorms, a LINET network was deployed around Manaus to depict the 3D lightning distributions in conjunction with a network of field mills installed around the Manacupuru site (T3). Such measurements were also augmented with cloud-to-ground lightning measurements of STARNET that covers all South America, and 3 radars at T3 site. CHUVA project provided a Dual Pol X band Doppler radar (XPOL) and one Micro Rain Radar (MRR), while GO-Amazon in conjunction with ARM provided a vertical pointing W Band Doppler radar (Cloud Radar). On September 8th 2014, a thunderstorm that lasted almost 3 hours crossed the super site T3 and produced more than 3,000 cloud to ground strokes and 5,000 intra-cloud lightning strokes. The vertical electrical field (Ez) was above (+-) 2 kV/m during the thunderstorm activity and reached as high as -9 kV/m. The Ez temporal evolution showed a classical end of storm oscillation with the first part of the rain producing negative Ez and after the maximum lightning activity having positive Ez. Into this respect the precipitation was carrying positive charges initially and negative charges afterward. The lightning rate varied from 2-7 strokes/second and during the maximum activity it reached 25 flashes per second. The intra-cloud lightning activity was concentrated mainly at 10 and 15 km with a second center between 5-9 km height. Radar measurements showed interesting features about this thunderstorm. The cloud radar showed cloud development as high as 12-14 km with -10 and 10 dBZ. The MRR showed radar reflectivity values above 50 dBZ during the maximum lightning activity and strong attenuation above 1-2 km height. The XPOL showed development above 14 km, but apparently the radome wetting decrease it sensitivity. For the conference, detailed analysis will be conducted to evaluate the correlation between the charge centers in this thunderstorm with the hydrometeors types to understand the behavior of the Ez oscillations. To compute the charge centers, we will use the inverse problem of Coulomb's Law (Morales et al, 2014; Larcerda et al. 2011 and 2013) by integrating the electrical field measurements with radar fields and LINET lightning positions. The hydrometeors types will be evaluated according Dolan and Rutledge (2009) after XPOL attenuation correction.