| Full text | |
| Author(s): |
Cecchini, Micael A.
;
Heymsfield, Andrew J.
;
Honeyager, Ryan
;
Field, Paul
;
Machado, Luiz A. T.
;
Da Silva Dias, Maria A. F.
Total Authors: 6
|
| Document type: | Journal article |
| Source: | JOURNAL OF THE ATMOSPHERIC SCIENCES; v. 79, n. 7, p. 14-pg., 2022-07-01. |
| Abstract | |
The retrieval of hail kinetic energy with weather radars or its simulation in numerical models is challenging because of the shape complexity and variable density of hailstones. We combine 3D scans of individual hailstones with measurements of the particle size distributions (PSD) and T-matrix calculations to understand how hail reflectivity Z changes when approximating hailstones as spheroids, as compared to the realistic shapes obtained by 3D scanning technology. Additionally, recent terminal velocity relations are used to compare Z to the hail kinetic energy flux E-.. We parameterize the hail backscattering cross sections at L, S, C, and X bands as a function of size between 0.5 and 5.0 cm, matching the range of the observed PSDs. The scattering calculations use the T-matrix method for size parameters below 1.0 and the discrete dipole approximation (DDA) method otherwise. The DDA calculations are done for 48 digital models of realistic hailstones of sizes between 1 and 5 cm. The DDA cross sections are calculated for multiple orientations and averaged assuming a fully random orientation distribution to provide a single value per hailstone. The T-matrix reflectivity assuming solid ice spheres presents negligible differences to DDA results for size parameters below 1.0. Therefore, T matrix was used to fill in the gaps left by the DDA calculations. The results are mapped to the same size bins of the observed PSDs, allowing the calculation of the radar reflectivity. This is then correlated to E-., allowing a potential improvement of past retrieval methods of E. from Z in multiple wavelengths. (AU) | |
| FAPESP's process: | 20/13273-9 - Anatomy of Convective Clouds over the Amazon (ACCA) |
| Grantee: | Micael Amore Cecchini |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 17/17047-0 - Aerosol and clouds life cycles in Amazonia: biogenic emissions, biomass burning and impacts on ecosystem |
| Grantee: | Paulo Eduardo Artaxo Netto |
| Support Opportunities: | Research Program on Global Climate Change - Thematic Grants |
| FAPESP's process: | 15/14497-0 - Nowcasting of intense thunderstorms and understanding of the physical processes inside clouds: the SOS-CHUVA (Severe Weather Observation System) |
| Grantee: | Luiz Augusto Toledo Machado |
| Support Opportunities: | Research Program on Global Climate Change - Thematic Grants |
| FAPESP's process: | 18/09082-3 - Particle size distribution characteristics of different ice species in the Gamma phase space |
| Grantee: | Micael Amore Cecchini |
| Support Opportunities: | Scholarships abroad - Research Internship - Post-doctor |
| FAPESP's process: | 17/04654-6 - Studying macro and microphysical phase spaces in thunderstorm clouds: insights for nowcasting techniques |
| Grantee: | Micael Amore Cecchini |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |