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
Observational operators for dual polarimetric radars in variational data assimilation systems (PolRad VAR v1.0)
Takuya Kawabata,Thomas Schwitalla,Ahoro Adachi,Hans-Stefan Bauer,Volker Wulfmeyer,Nobuhiro Nagumo,Hiroshi Yamauchi +6 more
TL;DR: In this article, the authors implemented two observational operators for dual polarimetric radars in two variational data assimilation systems: WRF Var and NHM-4DVAR, and assessed whether the linearized operators and the accuracy of the adjoint operators were good enough for implementation in variational systems.
Journal Article
On a more consistent definition of radar reflectivity
TL;DR: In this paper, the authors proposed an expression of the type 10 log 10 (Z/Z0) for radar reflectivity as an indicator of the minimum daily precipitation, but this cannot be extrapolated to all types of precipitation.
Journal ArticleDOI
Raindrop Size Distributions of North Indian Ocean Tropical Cyclones Observed at the Coastal and Inland Stations in South India
Balaji Kumar Seela,Jayalakshmi Janapati,C. K. Unnikrishnan,Pay Liam Lin,Jui Le Loh,Wei Yu Chang,Utpal Kumar,K. Krishna Reddy,Dong In Lee,Mannem Venkatrami Reddy +9 more
TL;DR: The current study summarizes the raindrop size distributions (RSDs) characteristic of the North Indian Ocean (NIO) tropical cyclones measured with ground-based disdrometers installed at the coastal and inland stations in south India.
Dynamics of Blood Drop Formation and Flight
TL;DR: In this article, the drop formation and flight dynamics of blood vessels were studied and the governing equations of drop formation were presented. But they did not consider the effects of drop deformation and deformation at the terminal velocity.
References
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Journal ArticleDOI
The terminal velocity of fall for water droplets in stagnant air
Ross Gunn,Gilbert D. Kinzer +1 more
TL;DR: In this article, the terminal velocities for distilled water droplets falling through stagnant air are accurately determined using a new method employing electronic techniques, and the over-all accuracy of the massterminal-velocity measurements is better than 0.7 per cent.
Book
Electromagnetic Wave Propagation, Radiation, and Scattering
TL;DR: In this article, the fundamental field equations of wave propagation in homogeneous and layered media waveguides and cavities have been studied, including the effects of a dipole on the conducting earth, inverse scattering radiometry, and interferometry numerical techniques.
Journal ArticleDOI
Potential Use of Radar Differential Reflectivity Measurements at Orthogonal Polarizations for Measuring Precipitation
T. A. Seliga,V. N. Bringi +1 more
TL;DR: In this paper, the potential use of differential reflectivity measurements at orthogonal polarizations to determine rain-fall rate was examined, which involves measurements of ZH and ZV, the radar reflectivity factors due to horizontally and vertically polarized incident waves respectively.
Journal ArticleDOI
A New Model for the Equilibrium Shape of Raindrops
TL;DR: In this paper, the equilibrium shape of raindrops has been determined from Laplace's equation using an internal hydrostatic pressure with an external aerodynamic pressure based on measurements for a sphere but adjusted for the effect of distortion.
Journal ArticleDOI
A wind tunnel investigation of the internal circulation and shape of water drops falling at terminal velocity in air
H. R. Pruppacher,K. V. Beard +1 more
TL;DR: The internal circulation and shape of water drops falling at terminal velocity in air of 20°C at sea level pressure, and nearly water saturated, were studied by means of a wind tunnel.