Amazonian squall line downdraft and cold-pool characteristics

Poster PDF

Description

Scanning precipitation radars provide the backbone for deep convective rain studies. This poster will first describe the Brazilian Army’s SIPAM S-band radar data set that has been processed for the entire two-year GoAmazon2014/15 period, including quality control procedures and higher-level precipitation products, and made available on the ARM archive. The next objective of the poster is to describe the concept and climatology of the SIPAM-derived descending arm, which represents the variability of the 3-D reflectivity in a 22 km x 22 km box. High variability is argued to indicate coincident strong up and downdrafts, which occur at the leading edge of squall lines and in the vicinity of strong, individual convective cells. The strong downdrafts often produce cold pools that can spread out and promote new convection. Chemical tracers, such as ozone, have also been observed to be transported downward by these strong convective events. We use vertical velocity and spectrum width information derived from the radar wind profiler and surface ozone observations made at T3 to characterize the downdraft height and strength associated with high ozone events. These events are shown to be consistent with the descending arm analysis from SIPAM. Next steps will be to compare the SIPAM observations with regional and climate models to test the level of agreement between the radar observations, high-resolution model output, and climate model cold-pool parameterizations.