TY - JOUR
T1 - Resonance scattering effects in wet hail observed with a dual-X-band-frequency, dual-polarization doppler on wheels radar
AU - Kumjian, Matthew R.
AU - Richardson, Yvette P.
AU - Meyer, Traeger
AU - Kosiba, Karen A.
AU - Wurman, Joshua
N1 - Funding Information:
Acknowledgments. The PSU-DROPS project was sponsored by an education and outreach grant from the National Science Foundation (NSF). Author MK is funded by NSF Award AGS-1661679 and by an award from the Insurance Institute for Business and Home Safety (IBHS). NSF support for the Center for Severe Weather Research comes from Grants AGS-1442054 and AGS-1361237. The authors thank Dr. Marcus van Lier-Walqui (NASA GISS) for helpful comments. DOW7 datasets are available from CSWR. We also acknowledge the extremely thorough and constructive reviews by the reviewers, which substantially improved the study.
Funding Information:
The PSU-DROPS project was sponsored by an education and outreach grant from the National Science Foundation (NSF). Author MK is funded by NSF Award AGS-1661679 and by an award from the Insurance Institute for Business and Home Safety (IBHS). NSF support for the Center for Severe Weather Research comes from Grants AGS-1442054 and AGS-1361237. The authors thank Dr. Marcus van Lier-Walqui (NASAGISS) for helpful comments.DOW7 datasets are available from CSWR. We also acknowledge the extremely thorough and constructive reviews by the reviewers, which substantially improved the study.
Publisher Copyright:
© 2018 American Meteorological Society.
PY - 2018
Y1 - 2018
N2 - Two of the "Doppler on Wheels" facility radars (DOW6 and DOW7) have been upgraded to dual-polarization capabilities and operate at two closely spaced X-band frequencies. For particles with sizes that are large relative to the wavelength, resonance scattering effects may lead to differences in the backscattered radiation between these two frequencies. This study investigates the utility of dual-frequency, dual-polarization DOW radars for hail detection and sizing. T-matrix scattering calculations at the two X-band DOW7 frequencies reveal that dual-frequency differences in the radar reflectivity factors at horizontal polarization (Δ λ Z H ) and differential reflectivities (Δ λ Z DR ) exist for hailstones, whereas negligible differences exist for raindrops. These differences are enhanced for wet or melting hailstones. Further, these dual-frequency differences may be positive or negative, thereby defining four distinct quadrants in the Δ λ Z H -Δ λ Z DR parameter space that occur for narrow bands of hail sizes. DOW7 data from two hail-bearing storms are analyzed: one produced only small hail, and the other produced severe hail up to ~3.8 cm in diameter. The analysis reveals dual-frequency signals that are consistent with the scattering calculations for those sizes, including consistent changes in the signatures below the melting layer in the first storm as hailstones acquire more liquid meltwater and a shift in the Δ λ ZH-Δ λ Z DR parameter space over time as the second storm grew upscale and hail sizes decreased. Implications for further applications and suggestions about closely spaced dual-frequency observations at other wavelengths are discussed.
AB - Two of the "Doppler on Wheels" facility radars (DOW6 and DOW7) have been upgraded to dual-polarization capabilities and operate at two closely spaced X-band frequencies. For particles with sizes that are large relative to the wavelength, resonance scattering effects may lead to differences in the backscattered radiation between these two frequencies. This study investigates the utility of dual-frequency, dual-polarization DOW radars for hail detection and sizing. T-matrix scattering calculations at the two X-band DOW7 frequencies reveal that dual-frequency differences in the radar reflectivity factors at horizontal polarization (Δ λ Z H ) and differential reflectivities (Δ λ Z DR ) exist for hailstones, whereas negligible differences exist for raindrops. These differences are enhanced for wet or melting hailstones. Further, these dual-frequency differences may be positive or negative, thereby defining four distinct quadrants in the Δ λ Z H -Δ λ Z DR parameter space that occur for narrow bands of hail sizes. DOW7 data from two hail-bearing storms are analyzed: one produced only small hail, and the other produced severe hail up to ~3.8 cm in diameter. The analysis reveals dual-frequency signals that are consistent with the scattering calculations for those sizes, including consistent changes in the signatures below the melting layer in the first storm as hailstones acquire more liquid meltwater and a shift in the Δ λ ZH-Δ λ Z DR parameter space over time as the second storm grew upscale and hail sizes decreased. Implications for further applications and suggestions about closely spaced dual-frequency observations at other wavelengths are discussed.
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U2 - 10.1175/JAMC-D-17-0362.1
DO - 10.1175/JAMC-D-17-0362.1
M3 - Article
AN - SCOPUS:85062156608
SN - 1558-8424
VL - 57
SP - 2713
EP - 2731
JO - Journal of Applied Meteorology and Climatology
JF - Journal of Applied Meteorology and Climatology
IS - 12
ER -