Inter-Zone Differences of Convective Development in a Convection Outbreak Event over Southeastern Coast of China: An Observational Analysis

Among the densely-populated coastal areas of China, the southeastern coast has received less attention in convective development despite having been suffering from significantly increasing thunderstorm activities. The convective complexity under such a region with extremely complex underlying and convective conditions deserves in-depth observational surveys. This present study examined a high-impact convection outbreak event with over 40 hail reports in the southeastern coast of China on 6 May 2020 by focusing on contrasting the convective development (from convective initiation to supercell occurrences) among three adjacent convection-active zones (north (N), middle (M), and south (S)). The areas from N to S featured overall flatter terrain, higher levels of free convection, lower relative humidity, larger convective inhibition, more convective available potential energy, and greater vertical wind shears. With these mesoscale environmental variations, distinct inter-zone differences in the convective development were observed with the region’s surveillance radar network and the Himawari-8 geostationary satellite. Convection initiated in succession from N to S and began with more warm-rain processes in N and M and more ice-phase processes in S. The subsequent convection underwent more vigorous vertical growth from N to S. The extremely deep convection in S was characterized by the considerably strong precipitation above the freezing level, echo tops of up to 18 km, and a great amount of deep (even overshooting) and thick convective clouds with significant cloud-top glaciation. Horizontal anvil expansion in convective clouds was uniquely apparent over S. From N to S, more pronounced mesocyclone and weak-echo region signatures indicated high risks of severe supercell hailstorms. These results demonstrate the strong linkage between the occurrence likelihood of severe convection and associated weather (such as supercells and hailstones) and the early-stage convective development that can be well-captured by high-resolution observations and may facilitate fine-scale convection nowcasting.

New records for associations between peritrich protozoan ciliates (Ciliophora, Sessilida) and polychaete worms (Annelida) from off the southeastern coast of India

We report herein three epibiotic associations between peritrich ciliate protozoans and polychaete worms, as observed in Tamilnadu, southeastern coast of India. Epibiont ciliates Epistylis sp.1 were found all over the integument of individuals of the terebellid polychaete Terebella sp., collected from Vellar estuary. Epistylis sp.2 ciliates were observed attached to Namalycastis abiuma polychaetes, on both sides of parapodia. Cothurnia sp. ciliates were found on anterior most paleae and hooks of Sabellaria sp. polychaetes, both latter associations from material from the Uppanar estuary. Those epibiont/basibiont associations are all new to science and discussed herein, together with a review on the previous reports of epibiont ciliate protozoans in Indian waters.