Monday, 13 January 2020
Hall B1 (Boston Convention and Exhibition Center)
Understanding hailstorms and extreme precipitation events in a complex topography and a tropical environment such as the Aburrá Valley, located in the Colombian Andes is relevant for in the context of risk management. When hailstones reach the ground can generate considerable losses, including the destruction of crops. Characterization of all rain events (RE) and the combined hail with rain events (HE) in the region is carried out analyzing five years of information from seven in-situ laser precipitation monitors (LPM disdrometers) with a 1-minute resolution, and reflectivity from a Doppler dual-polarization C-band weather radar. Variables such as horizontal, vertical and differential reflectivity, co-polar correlation and differential specific phase, known for being useful to classify hydrometeors due to their dependence on the shape, size, and orientation of the particles, were considered in the assessment. Information from a weather station and a pyranometer was also considered, the former surface temperature changes when as a function of precipitation type, allowing an assessment of the resulting cold pool near the surface, and the latter to examine the effect on radiation due to RE and HE events. Furthermore, we use satellite-based and in-situ remote sensors to obtain a full view of these events, including a Micro Rain Radar (MRR) and a microwave radiometer to study the vertical structure of each type of precipitation, and finally ABI-data from GOES-East satellite for a larger scale perspective. Results show distinct polar signatures probability density functions for RE and HE, allowing discrimination between rainfall and hailstorm events. Regarding the formation of a surface cold pool, temperature gradient diagrams show significantly larger negative anomalies associated with HE than for RE. Additionally, vertical profiles of reflectivity during HE shows values between 40 and 60 dBZ with a higher frequency of occurrence than during RE, near ground level, and at higher altitudes.
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