Pre-processing and Assessment of Rain Drop Size Distributions Measured with a K-band Doppler Radar and an Optical Disdrometer

2020 ◽  
pp. 1-1
Author(s):  
Jose Manuel Riera ◽  
Ana Benarroch ◽  
Pedro Garcia-del-Pino ◽  
Santiago Perez-Pena
Keyword(s):  
Drop Size ◽  
Doppler Radar ◽  
Size Distributions ◽  
Rain Drop ◽  
Drop Size Distributions ◽  
K Band

scholarly journals Raindrop Size Distribution and Rain Characteristics during the 2013 Great Colorado Flood

2015 ◽  
Vol 17 (1) ◽  
pp. 53-72 ◽  
Author(s):  
Katja Friedrich ◽  
Evan A. Kalina ◽  
Joshua Aikins ◽  
Matthias Steiner ◽  
David Gochis ◽  
...  
Keyword(s):  
Drop Size ◽  
Doppler Radar ◽  
Liquid Water Content ◽  
Size Distributions ◽  
Intense Rainfall ◽  
Wind Fields ◽  
Raindrop Size Distribution ◽  
Median Volume ◽  
Drop Size Distributions ◽  
Analysis System

Abstract Drop size distributions observed by four Particle Size Velocity (PARSIVEL) disdrometers during the 2013 Great Colorado Flood are used to diagnose rain characteristics during intensive rainfall episodes. The analysis focuses on 30 h of intense rainfall in the vicinity of Boulder, Colorado, from 2200 UTC 11 September to 0400 UTC 13 September 2013. Rainfall rates R, median volume diameters D0, reflectivity Z, drop size distributions (DSDs), and gamma DSD parameters were derived and compared between the foothills and adjacent plains locations. Rainfall throughout the entire event was characterized by a large number of small- to medium-sized raindrops (diameters smaller than 1.5 mm) resulting in small values of Z (<40 dBZ), differential reflectivity Zdr (<1.3 dB), specific differential phase Kdp (<1° km−1), and D0 (<1 mm). In addition, high liquid water content was present throughout the entire event. Raindrops observed in the plains were generally larger than those in the foothills. DSDs observed in the foothills were characterized by a large concentration of small-sized drops (d < 1 mm). Heavy rainfall rates with slightly larger drops were observed during the first intense rainfall episode (0000–0800 UTC 12 September) and were associated with areas of enhanced low-level convergence and vertical velocity according to the wind fields derived from the Variational Doppler Radar Analysis System. The disdrometer-derived Z–R relationships reflect how unusual the DSDs were during the 2013 Great Colorado Flood. As a result, Z–R relations commonly used by the operational NEXRAD strongly underestimated rainfall rates by up to 43%.

Computer processing for deriving drop-size distributions and vertical air velocities from VHF Doppler radar spectra

Radio Science ◽  
1990 ◽  
Vol 25 (5) ◽  
pp. 961-973 ◽  
Author(s):  
Toru Sato ◽  
Hiroshi Doji ◽  
Hisato Iwai ◽  
Iwane Kimura ◽  
Shoichiro Fukao ◽  
...  
Keyword(s):  
Drop Size ◽  
Doppler Radar ◽  
Computer Processing ◽  
Size Distributions ◽  
Drop Size Distributions

scholarly journals The effect of reported high-velocity small raindrops on inferred drop size distributions and derived power laws

2010 ◽  
Vol 10 (4) ◽  
pp. 9121-9151 ◽  
Author(s):  
H. Leijnse ◽  
R. Uijlenhoet
Keyword(s):  
High Velocity ◽  
Drop Size ◽  
Doppler Radar ◽  
Probability Distributions ◽  
Power Laws ◽  
Size Distributions ◽  
Optical Links ◽  
Gamma Distributions ◽  
Raindrop Size Distribution ◽  
Drop Size Distributions

Abstract. It has recently been shown that at high rainfall intensities, small raindrops may fall with much larger velocities than would be expected from their diameters. These were argued to be fragments of recently broken-up larger drops. In this paper we quantify the effect of this phenomenon on raindrop size distribution measurements from a Joss-Waldvogel disdrometer, a 2-D Video Distrometer, and a vertically-pointing Doppler radar. Probability distributions of fall velocities have been parameterized, where the parameters are functions of both rainfall intensity and drop size. These parameterizations have been used to correct Joss-Waldvogel disdrometer measurements for this phenomenon. The effect of these corrections on fitted scaled drop size distributions are apparent but not major. Fitted gamma distributions for three different types of rainfall have been used to simulate drop size measurements. The effect of the high-velocity small drops is shown to be minor. Especially for the purpose of remote sensing of rainfall using radar, microwave links, or optical links, the errors caused by using the slightly different retrieval relations will be masked completely by other error sources.

scholarly journals The effect of reported high-velocity small raindrops on inferred drop size distributions and derived power laws

2010 ◽  
Vol 10 (14) ◽  
pp. 6807-6818 ◽  
Author(s):  
H. Leijnse ◽  
R. Uijlenhoet
Keyword(s):  
High Velocity ◽  
Drop Size ◽  
Doppler Radar ◽  
Probability Distributions ◽  
Power Laws ◽  
Size Distributions ◽  
Optical Links ◽  
Gamma Distributions ◽  
Raindrop Size Distribution ◽  
Drop Size Distributions

Abstract. It has recently been shown that at high rainfall intensities, small raindrops may fall with much larger velocities than would be expected from their diameters. These were argued to be fragments of recently broken-up larger drops. In this paper we quantify the effect of this phenomenon on raindrop size distribution measurements from a Joss-Waldvogel disdrometer, a 2-D Video Distrometer, and a vertically-pointing Doppler radar. Probability distributions of fall velocities have been parameterized, where the parameters are functions of both rainfall intensity and drop size. These parameterizations have been used to correct Joss-Waldvogel disdrometer measurements for this phenomenon. The effect of these corrections on fitted scaled drop size distributions are apparent but not major. Fitted gamma distributions for three different types of rainfall have been used to simulate drop size measurements. The effect of the high-velocity small drops is shown to be minor. Especially for the purpose of remote sensing of rainfall using radar, microwave links, or optical links, the errors caused by using the slightly different retrieval relations will be masked completely by other error sources.

scholarly journals Comparison of simultaneous rain drop size distributions estimated from two surface disdrometers and a UHF profiler

2000 ◽  
Vol 27 (12) ◽  
pp. 1763-1766 ◽  
Author(s):  
Christopher R. Williams ◽  
Anton Kruger ◽  
Kenneth S. Gage ◽  
Ali Tokay ◽  
Robert Cifelli ◽  
...  
Keyword(s):  
Drop Size ◽  
Size Distributions ◽  
Rain Drop ◽  
Drop Size Distributions

scholarly journals On the Realism of the Rain Microphysics Representation of a Squall Line in the WRF Model. Part II: Sensitivity Studies on the Rain Drop Size Distributions

2019 ◽  
Vol 147 (8) ◽  
pp. 2811-2825 ◽  
Author(s):  
Céline Planche ◽  
Frédéric Tridon ◽  
Sandra Banson ◽  
Gregory Thompson ◽  
Marie Monier ◽  
...  
Keyword(s):  
Drop Size ◽  
Wrf Model ◽  
Melting Process ◽  
Squall Line ◽  
Size Distributions ◽  
Line System ◽  
Stratiform Region ◽  
Rain Drop ◽  
Vertical Evolution ◽  
Drop Size Distributions

Abstract A comparison between retrieved properties of the rain drop size distributions (DSDs) from multifrequency cloud radar observations and WRF Model results using either the Morrison or the Thompson bulk microphysics scheme is performed in order to evaluate the model’s ability to predict the rain microphysics. This comparison reveals discrepancies in the vertical profile of the rain DSDs for the stratiform region of the squall-line system observed on 12 June 2011 over Oklahoma. Based on numerical sensitivity analyses, this study addresses the bias at the top of the rain layer and the vertical evolution of the DSD properties (i.e., of Dm and N0*). In this way, the Thompson scheme is used to explore the sensitivity to the melting process. Moreover, using the Thompson and Morrison schemes, the sensitivity of the DSD vertical evolution to different breakup and self-collection parameterizations is studied. Results show that the DSDs are strongly dependent on the representation of the melting process in the Thompson scheme. In the Morrison scheme, the simulations with more efficient breakup reproduce the DSD properties with better fidelity. This study highlights how the inaccuracies in simulated Dm and N0* for both microphysics schemes can impact the evaporation rate, which is systematically underestimated in the model.

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