Diagnosing the Intercept Parameter for Exponential Raindrop Size Distribution Based on Video Disdrometer Observations: Model Development

2008 ◽  
Vol 47 (11) ◽  
pp. 2983-2992 ◽  
Author(s):  
Guifu Zhang ◽  
Ming Xue ◽  
Qing Cao ◽  
Daniel Dawson
Keyword(s):  
Size Distribution ◽  
Sampling Error ◽  
Model Development ◽  
Parameterization Scheme ◽  
Clear Correlation ◽  
Rainfall Estimation ◽  
Warm Rain ◽  
Raindrop Size Distribution ◽  
Single Moment ◽  
Raindrop Size

Abstract The exponential distribution N(D) = N0 exp(−ΛD) with a fixed intercept parameter N0 is most commonly used to represent raindrop size distribution (DSD) in rainfall estimation and in single-moment bulk microphysics parameterization schemes. Disdrometer observations show that the intercept parameter is far from constant and systematically depends on the rain type and intensity. In this study, a diagnostic relation of N0 as a function of rainwater content W is derived based on two-dimensional video disdrometer (2DVD) measurements. The data reveal a clear correlation between N0 and W in which N0 increases as W increases. To minimize the effects of sampling error, a relation between two middle moments is used to derive the N0–W relation. This diagnostic relation has the potential to improve rainfall estimation and bulk microphysics parameterizations. A parameterization scheme for warm rain processes based on the diagnostic N0 DSD model is formulated and presented. The diagnostic N0-based parameterization scheme yields less evaporation and accretion for stratiform rain than that using fixed N0.

scholarly journals Statistical characteristics of raindrop size distribution over Western Ghats of India: wet versus dry spells of Indian Summer Monsoon

2019 ◽  
Author(s):  
Uriya Veerendra Murali Krishna ◽  
Subrata Kumar Das ◽  
Ezhilarasi Govindaraj Sulochana ◽  
Bhowmik Utsav ◽  
Sachin Madhukar Deshpande ◽  
...  
Keyword(s):  
Size Distribution ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Diurnal Cycle ◽  
Western Ghats ◽  
Warm Rain ◽  
Raindrop Size Distribution ◽  
Dry Spells ◽  
Western Ghats Of India ◽  
Raindrop Size

Abstract. The nature of raindrop size distribution (DSD) is analyzed during wet and dry spells of the Indian Summer Monsoon (ISM) over Western Ghats (WGs) using Joss-Waldvogel Disdrometer (JWD) measurements. The observed DSDs are fitted with gamma distribution, and the characteristic DSDs are studied during the summer monsoon seasons (June–September) of 2012–2015. The DSD spectra show distinct diurnal variation during wet and dry spells. The dry spells exhibit a strong diurnal cycle with two peaks, while the diurnal cycle is not prominent in the wet spells. The observational results reveal the microphysical characteristics of warm rain during both the wet and dry spells. Even though the warm rain processes are dominant over WGs during monsoon, the underlying dynamical processes cause the differences in DSD characteristics during wet and dry spells. In addition, the differences in DSD spectra with different rain rates are also observed during the wet and dry spells. The DSD spectra are further analyzed by separating into stratiform and convective types. Finally, an empirical relation between slope parameter, Λ and shape parameter, μ is derived by best fitting the quadratic polynomial for the observed data during both wet and dry spells as well as for the stratiform and convective types of precipitation. The Λ–μ relations obtained in the present study are slightly different in comparison with the earlier studies.

Optimized raindrop size distribution retrieval and quantitative rainfall estimation from polarimetric radar

2020 ◽  
Vol 580 ◽  
pp. 124248 ◽  
Author(s):  
Hao Huang ◽  
Kun Zhao ◽  
Guifu Zhang ◽  
Dongming Hu ◽  
Zhengwei Yang
Keyword(s):  
Size Distribution ◽  
Polarimetric Radar ◽  
Rainfall Estimation ◽  
Raindrop Size Distribution ◽  
Raindrop Size

scholarly journals On Raindrop-size Distribution in Warm Rain (I)

1971 ◽  
Vol 22 (2) ◽  
pp. 61-68 ◽  
Author(s):  
Miyuki Fujiwara ◽  
Toshiko Yanase
Keyword(s):  
Size Distribution ◽  
Warm Rain ◽  
Raindrop Size Distribution ◽  
Raindrop Size

scholarly journals Raindrop size distribution in warm rain as measured in Hawaii

Tellus ◽  
1967 ◽  
Vol 19 (3) ◽  
pp. 392-402 ◽  
Author(s):  
Miyuki Fujiwara
Keyword(s):  
Size Distribution ◽  
Warm Rain ◽  
Raindrop Size Distribution ◽  
Raindrop Size

scholarly journals Statistical characteristics of raindrop size distribution during rainy seasons in the Beijing urban area and implications for radar rainfall estimation

2019 ◽  
Vol 23 (10) ◽  
pp. 4153-4170 ◽  
Author(s):  
Yu Ma ◽  
Guangheng Ni ◽  
Chandrasekar V. Chandra ◽  
Fuqiang Tian ◽  
Haonan Chen
Keyword(s):  
Size Distribution ◽  
Urban Area ◽  
Rain Rate ◽  
Statistical Characteristics ◽  
Spatial And Temporal Variability ◽  
Rainfall Estimation ◽  
Radar Rainfall ◽  
Convective Rain ◽  
Raindrop Size Distribution ◽  
Raindrop Size

Abstract. Raindrop size distribution (DSD) information is fundamental in understanding the precipitation microphysics and quantitative precipitation estimation, especially in complex terrain or urban environments which are known for complicated rainfall mechanism and high spatial and temporal variability. In this study, the DSD characteristics of rainy seasons in the Beijing urban area are extensively investigated using 5-year DSD observations from a Parsivel2 disdrometer located at Tsinghua University. The results show that the DSD samples with rain rate < 1 mm h−1 account for more than half of total observations. The mean values of the normalized intercept parameter (log 10Nw) and the mass-weighted mean diameter (Dm) of convective rain are higher than that of stratiform rain, and there is a clear boundary between the two types of rain in terms of the scattergram of log 10Nw versus Dm. The convective rain in Beijing is neither continental nor maritime, owing to the particular location and local topography. As the rainfall intensity increases, the DSD spectra become higher and wider, but they still have peaks around diameter D∼0.5 mm. The midsize drops contribute most towards accumulated rainwater. The Dm and log 10Nw values exhibit a diurnal cycle and an annual cycle. In addition, at the stage characterized by an abrupt rise of urban heat island (UHI) intensity as well as the stage of strong UHI intensity during the day, DSD shows higher Dm values and lower log 10Nw values. The localized radar reflectivity (Z) and rain rate (R) relations (Z=aRb) show substantial differences compared to the commonly used NEXRAD relationships, and the polarimetric radar algorithms R(Kdp), R(Kdp, ZDR), and R(ZH, ZDR) show greater potential for rainfall estimation.

scholarly journals Statistical characteristics of raindrop size distribution during rainy seasons in Beijing urban area and implications for radar rainfall estimation

2019 ◽  
Author(s):  
Yu Ma ◽  
Guangheng Ni ◽  
V. Chandrasekar ◽  
Fuqiang Tian ◽  
Haonan Chen
Keyword(s):  
Size Distribution ◽  
Urban Area ◽  
Rain Rate ◽  
Statistical Characteristics ◽  
Spatial And Temporal Variability ◽  
Rainfall Estimation ◽  
Radar Rainfall ◽  
Convective Rain ◽  
Raindrop Size Distribution ◽  
Raindrop Size

Abstract. Raindrop size distribution (DSD) information is fundamental in understanding the precipitation microphysics and quantitative precipitation estimation, especially in complex terrain or urban environment which is known for its complicated rainfall mechanism and high spatial and temporal variability. In this study, the DSD characteristics of rainy seasons in Beijing urban area are extensively investigated using 5-year DSD observations from a Parsivel2 disdrometer located at Tsinghua University. The results show that the DSD samples with rain rate < 1 mm h−1 account for more than half of total observations. The mean values of log10 Nw and Dm of convective rain are higher than that of stratiform rain, and there is a clear boundary between the two types of rain in terms of the scattergram of log10Nw versus Dm. The convective rain in Beijing is neither continental nor maritime owing to the particular location and local topography. As the rainfall intensity increases, the DSD spectra become higher and wider, but they still have peaks around diameter D ~ 0.5 mm. The midsize drops contribute most towards accumulated rainwater. The Dm and log10Nw values show a diurnal cycle and an annual cycle. In addition, DSD shows higher Dm values and lower log10Nw values during the periods of strong urban heat island (UHI) effect and UHI up stage of a day, and the same in July and August. The localized radar reflectivity (Z) and rain rate (R) relations (Z = aRb) show substantial differences compared to the commonly used NEXRAD relationships. And the polarimetric radar algorithms R(Kdp), R(Kdp, ZDR), and R(ZH, ZDR) show greater potential for rainfall estimation.

scholarly journals Statistical characteristics of raindrop size distribution over Western Ghats of India: wet versus dry spells of Indian Summer Monsoon

2020 ◽  
Author(s):  
Uriya Veerendra Murali Krishna ◽  
Subrata Kumar Das ◽  
Ezhilarasi Govindaraj Sulochana ◽  
Bhowmik Utsav ◽  
Sachin Madhukar Deshpande ◽  
...  
Keyword(s):  
Size Distribution ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Diurnal Cycle ◽  
Western Ghats ◽  
Warm Rain ◽  
Raindrop Size Distribution ◽  
Dry Spells ◽  
Western Ghats Of India ◽  
Raindrop Size

Abstract. The nature of raindrop size distribution (DSD) is analyzed during wet and dry spells of the Indian Summer Monsoon (ISM) in the Western Ghats (WGs) region by using Joss-Waldvogel Disdrometer (JWD) measurements. The observed DSDs are fitted with gamma distribution, and the DSD characteristics are studied during ISM season (June–September) of 2012–2015. The DSD spectra show distinct diurnal variation during the wet and dry spells. The dry spells exhibit a strong diurnal cycle with two peaks, while the diurnal cycle is not so prominent in the wet spells. Results reveal the microphysical characteristics of warm rain during both the wet and dry periods. Even though the warm rain processes are dominant in the WGs region, the underlying dynamical processes cause the differences in DSD characteristics during the wet and dry spells. In addition, the differences in DSD spectra with different rain rates are also observed. The DSD spectra are further analyzed by separating into stratiform and convective types. Finally, an empirical relationship between the slope parameter, Λ and shape parameter, µ is derived by best fitting the quadratic polynomial for the observed data during both wet and dry spells as well as for the stratiform and convective types of rain. The µ-Λ relations obtained in the present study are slightly different in comparison with the previous studies.

Sign in / Sign up

Export Citation Format

Share Document