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Radar wind profiler investigations into MCSs characteristics

Presentation Date
Wednesday, December 12, 2018 at 11:05am
Location
Walter E Washington Convention Center 150B
Authors

Author

Abstract

Mesoscale convective systems (MCSs) regulate the global energy cycle through their extensive cloud coverage and the exchange of latent heat, and are associated with a large proportion of extreme precipitation events. The dynamic and thermodynamic processes within MCSs are complex, exhibiting a variety of convective and stratiform cloud characteristics in tropical and continental regions. This study contrasts properties of extended ground-based radar wind profiler (RWP) mature MCS datasets collected over tropical and mid-latitude regions. Multi-instrument datasets from DOE Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Site in Oklahoma, U.S. (16 events) and the ARM mobile deployment to Manaus, Brazil (GoAmazon2014/5, 46 events) are covered.

Tropical and mid-latitude MCSs both show a deep leading convective updraft with comparable precipitation rates and a broader trailing stratiform precipitation regions. Surface cold pools developed beneath the convective cores and are associated with sharpest drops (∼10 K) in surface equivalent potential temperature (θe) during the system passage. The θe drops at the surface have a robust relationship with precipitation rate and probability across regions, suggesting their potential use in model evaluations and downdraft parameterization improvement. Compared to tropical MCSs, mid-latitude MCSs are consistent in displaying an upper-level leading anvil, and higher reflectivity in trailing stratiform (more developed aggregation processes). SGP MCSs also suggest more intense, but narrower updrafts in the middle-upper troposphere, peaking at higher altitudes (10 km, on average), as well as deeper and stronger precipitation-driven downdrafts that could originate from mid-levels (up to 6 km) if substantial mixing occurs (χ = 0.34 km-1). SGP datasets also indicate drier and colder cool pools at the surface.

Category
Atmospheric Sciences