Journal ArticleDOI
Experiments in Rainfall Estimation with a Polarimetric Radar in a Subtropical Environment
TLDR
In this paper, a unique dataset consisting of high-resolution polarimetric radar measurements and dense rain gauge and disdrometer observations collected in east-central Florida during the summer of 1998 was examined.Abstract:
A unique dataset consisting of high-resolution polarimetric radar measurements and dense rain gauge and disdrometer observations collected in east-central Florida during the summer of 1998 was examined. Comparison of the radar measurements and radar parameters computed from the disdrometer observations supported previous studies, which indicate that oscillating drops in the free atmosphere have more spherical apparent shapes in the mean than equilibrium shapes. Radar‐disdrometer comparisons improved markedly when using an empirical axis ratio relation developed from observational studies and representing more spherical drop shapes. Fixedform power-law rainfall estimators for radar reflectivity ( ZH), specific differential phase (KDP), specific differential phase‐differential reflectivity ( KDP, ZDR), and radar reflectivity‐differential reflectivity ( ZH, ZDR) were then determined using the disdrometer observations. Relations were produced for both equilibrium shapes and the empirical axis ratios. Polarimetric rainfall estimators based on more spherical shapes gave significantly improved performance. However, the improvement was largely in bias mitigation. Rainfall estimates with the ZH‐ZDR measurement pair had the highest correlation with rain gauge observations, the smallest range in bias factors from storm to storm, and the smallest root-mean-square error.read more
Citations
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Journal ArticleDOI
Precipitation: Measurement, remote sensing, climatology and modeling
Silas Michaelides,Vincenzo Levizzani,Emmanouil N. Anagnostou,Peter Bauer,Takis Kasparis,John E. Lane +5 more
TL;DR: In this paper, a review of the current status and main outstanding issues related to precipitation forecasting are discussed, providing a basic structure for research coordination aimed at the improvement of modeling, observation and data assimilation applicable to global and regional scales.
Journal ArticleDOI
Rainfall Estimation with a Polarimetric Prototype of WSR-88D
TL;DR: In this paper, a synthetic polarimetric algorithm has been developed for rainfall estimation, which results in significant reduction in the rms errors of hourly rain estimates when compared with the conventional nonpolarimetric relation.
Journal ArticleDOI
A Statistical and Physical Description of Hydrometeor Distributions in Colorado Snowstorms Using a Video Disdrometer
TL;DR: In this paper, a two-dimensional video disdrometer was used to determine the form of particle size distributions (PSDs) and search for useful interrelationships among the governing parameters of assumed distribution forms and environmental factors.
Journal ArticleDOI
Calibration Issues of Dual-Polarization Radar Measurements
TL;DR: In this paper, a self-consistency approach was proposed to reduce the impact of variability in the drop size distribution and raindrop shape on the quality of the radar reflectivity Z. The proposed scheme was tested on a large polarimetric dataset obtained during the Joint Polarization Experiment in Oklahoma and yielded an accura...
Journal ArticleDOI
Analysis of Video Disdrometer and Polarimetric Radar Data to Characterize Rain Microphysics in Oklahoma
TL;DR: In this paper, data from three 2D video disdrometers and an S-band polarimetric radar are used to characterize rain microphysics in Oklahoma and a method of sorting and averaging based on two parameters (SATP) is proposed.
References
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Journal ArticleDOI
Error Structure of Multiparameter Radar and Surface Measurements of Rainfall. Part III: Specific Differential Phase
TL;DR: In this paper, the error structure of the specific differential phase (KDP, °km−1) measurement in rainfall was analyzed, and the results showed that KDP can be used to estimate the rainfall rate.
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An Approximation for the Shapes of Large Raindrops
TL;DR: In this paper, a simple model for approximating the shapes of raindrops in terminal fall equilibrium is proposed, which can be represented approximately as oblate spheroids, which have axis ratios determined by the balance of surface and gravity forces at the equator.
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Assessment of Rainfall Measurement That Uses Specific Differential Phase
TL;DR: In this article, the authors examined some effects of drop size distribution and shape on the rainfall-rate estimates obtained from the specific differential phase and presented an algorithm that uses exclusively the specific discrete phase.
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Adjustment of tipping-bucket precipitation gauge measurements
TL;DR: The 6-year mean annual difference in precipitation values as measured using the Hellmann gauge and the tipping-bucket recording precipitation gauge at the same open site at the Airport of Geneva amounts to 14%.
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Comparison of Dual-Polarization Radar Estimators of Rain
TL;DR: In this article, several polarimetric radar estimators of rain rate R and rainwater content M were examined using a gamma drop size distribution (DSD) simulation and a radar wavelength of 11 cm.