Characteristics of raindrop spectra as normalized gamma distribution from a Joss–Waldvogel disdrometer

Islam, Tanvir; Rico‐Ramirez, Miguel A.; Thurai, Merhala; Han, Dawei

doi:10.1016/j.atmosres.2012.01.013

Cited by 66 publications

(67 citation statements)

References 62 publications

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“…For a two-moment scheme with a fixed μ, it was found that the microphysical properties of cloud and precipitation are sensitive to the μ values, since the shape parameter plays an important role in determining sedimentation and microphysical growth rates (Milbrandt and Yau 2005). Variations of μ during precipitation events have been reported in previous studies (e.g., Ulbrich 1983; Ulbrich and Atlas 1998;Testud et al 2001;Zhang et al 2001;Islam et al 2012). Considering that the three parameters of the gamma distribution are not independent of each other, an empirical relationship between N0 and μ (Ulbrich 1983) or between μ and Λ (Zhang et al 2001) has been proposed to retrieve a gamma distribution.…”

Section: Shape-slope Relationmentioning

confidence: 83%

Statistical Characteristics of Raindrop Size Distribution in the Meiyu Season Observed in Eastern China

Chen

Yang

2013

Journal of the Meteorological Society of Japan

139

186

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Characteristics of raindrop size distribution (DSD) during the Meiyu season are studied using ground-based disdrometer measurements carried out in eastern China (Nanjing) from 2009 to 2011. The observational spectra are divided into convective and stratiform types. The results show that the histograms of the logarithm of the generalized intercept parameter (log10NW) and mass-weighted mean diameter of raindrops (Dm) are negatively and positively skewed, respectively, for both convective and stratiform rain. The absolute value of the skewness coefficient is higher for convective rain than for stratiform rain, in particular for the log10NW distribution. The mean log10NW and Dm values are 3.80 and 1.71 mm for convective rain and 3.45 and 1.30 mm for stratiform rain, respectively. The shape (μ)̶slope (Λ) relationship of the gamma distribution and the radar reflectivity (Z)̶rain rate (R) relationship are also derived for convective rain. The Z̶R relationship is found to be Z = 368R 1.21 . The interpretation of the statistical parameters obtained in this study and possible mechanisms that yield difference and similarity in comparison with those in previous studies are discussed.

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Section: Shape-slope Relationmentioning

confidence: 83%

Statistical Characteristics of Raindrop Size Distribution in the Meiyu Season Observed in Eastern China

Chen

Yang

2013

Journal of the Meteorological Society of Japan

139

186

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“…Thus, different investigations carried out on the A and b coefficients of the necessary relationship Z-R have allowed identifying two schools. The first one showed that the coefficient A is higher in the convective part than in the stratiform part of a same squall line [21] whereas the second one, sustained by authors such as Tokay and Short [20], Atlas et al [14], Narayana et al [25], Maki et al [15] and T. Islam et al [7], indicated that coefficient A is higher in stratiform than in convective rain. In other words, there is no clear trend in all of these studies and the question is still opened.…”

Section: Introductionmentioning

confidence: 86%

“…They showed the existence of three cases noted C 1 (A c < A s and b c b s ) and C 3 (A c > A s and b c < b s ) from a given squall line to another (the letters c and s in index indicate respectively the convective or stratiform nature of rainfall). Their results revealed the coexistence of the above mentioned two schools, allowing finding the results from Yuter and Houze [21] through the case C 3 as well as those of Tokay and Short [20] and T. Islam et al [7] through the cases C 1 and C 2 . Therefore, they have considered that the difference between the two schools could be explained by the fact that the microphysical conditions, responsible for the rainfall production, were different.…”

Section: Introductionmentioning

confidence: 95%

“…Numerous studies showed that empirical function of the form Z = AR b describes well this relationship [8]- [13]. Authors such as, Sauvageot and Lacaux [2], Atlas et al [14], Maki et al [15] and more recently Moumouni et al [16], Ochou et al [17] and T. Islam et al [7] among others, indicated a great variability in space and time of this relationship according to local climatological, dynamic conditions and rain type.…”

Section: Introductionmentioning

confidence: 99%

“…From these measurements, establishment of a relationship between the rain rate R (mm/h) and the radar reflectivity factor Z (mm 6 •m −3 ) is useful for remote sensing estimation of rain by radar [1]- [7]. Numerous studies showed that empirical function of the form Z = AR b describes well this relationship [8]- [13].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Consistency in Z-R Relationship Variability Regardless Precipitating Systems, Climatic Zones Observed from Two Types of Disdrometer

Bamba¹,

Ochou²,

Zahiri³

et al. 2014

ACS

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Data from rain Drop Size Distributions gathered on five sites in Africa as well as those of the pilot site in Kourou (French Guyana, South America), located in different climatic zones, and collected by two types of disdrometer (the impact JW RD-69 disdrometer and the Optical Spectro-Pluviometer, OSP) are used to study the consistency of the reflectivity factor-rain rate at the ground (Z-R) relationship variability. The results clearly confirm that the relationship Z-R knows a large spatial variability, from a type of precipitation to another and within the same precipitation regardless the type of disdrometer used for DSD measurements. Base on the similarity of the relations reflectivity factor-rain rate and ratio median volume diameter over the total number of drops-rain rate, the variability of the Z-R coefficients (A, b) through the simultaneously implication of the size and number of drops which characterize the DSD was exhibited. It was shown that the relationships A-α and b-β designed to understand the involvement of parameters D0 and NT of DSD in the variability of the relationship Z-R are similar regardless the types of disdrometer used. However, the relations A-α in the Sahelian region appear to deviate from those of Guinean, equatorial and Soudanian zones. The plausible reasons were discussed.

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Exploration of discrepancy between radar and gauge rainfall estimates driven by wind fields

Dai

Han

2014

Water Resources Research

Self Cite

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Due to the fact that weather radar is prone to several sources of errors, it is acknowledged that adjustment against ground observations such as rain gauges is crucial for radar measurement. Spatial matching of precipitation patterns between radar and rain gauge is a significant premise in radar bias corrections. It is a conventional way to construct radar-gauge pairs based on their vertical locations. However, due to the wind effects, the raindrops observed by the radar do not always fall vertically to the ground, and the raindrops arriving at the ground may not all be caught by the rain gauge. This study proposes a fully formulated scheme to numerically simulate the movement of raindrops in a three-dimensional wind field in order to adjust the wind-induced errors. The Brue catchment (135 km 2 ) in Southwest England covering 28 radar pixels and 49 rain gauges is an experimental catchment, where the radar central beam height varies between 500 and 700 m. The 20 typical events (with durations of 6-36 h) are chosen to assess the correlation between hourly radar and gauge rainfall surfaces. It is found that for most events, the improved rates of correlation coefficients are greater than 10%, and nearly half of the events increase by 20%. With the proposed method, except four events, all the event-averaged correlation values are greater than 0.5. This work is the first study to tackle both wind effects on radar and rain gauges, which could be considered as one of the essential components in processing radar observational data in its hydrometeorological applications.

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Characteristics of raindrop spectra as normalized gamma distribution from a Joss–Waldvogel disdrometer

Cited by 66 publications

References 62 publications

Statistical Characteristics of Raindrop Size Distribution in the Meiyu Season Observed in Eastern China

Statistical Characteristics of Raindrop Size Distribution in the Meiyu Season Observed in Eastern China

Consistency in <i>Z</i>-<i>R</i> Relationship Variability Regardless Precipitating Systems, Climatic Zones Observed from Two Types of Disdrometer

Exploration of discrepancy between radar and gauge rainfall estimates driven by wind fields

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Characteristics of raindrop spectra as normalized gamma distribution from a Joss–Waldvogel disdrometer

Cited by 66 publications

References 62 publications

Statistical Characteristics of Raindrop Size Distribution in the Meiyu Season Observed in Eastern China

Statistical Characteristics of Raindrop Size Distribution in the Meiyu Season Observed in Eastern China

Consistency in &lt;i&gt;Z&lt;/i&gt;-&lt;i&gt;R&lt;/i&gt; Relationship Variability Regardless Precipitating Systems, Climatic Zones Observed from Two Types of Disdrometer

Exploration of discrepancy between radar and gauge rainfall estimates driven by wind fields

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Consistency in <i>Z</i>-<i>R</i> Relationship Variability Regardless Precipitating Systems, Climatic Zones Observed from Two Types of Disdrometer