Raindrop size distribution of different cloud types over the Western Ghats using simultaneous measurements from Micro-Rain Radar and disdrometer

2017 ◽  
Vol 186 ◽  
pp. 72-82 ◽  
Author(s):  
Subrata Kumar Das ◽  
Mahen Konwar ◽  
Kaustav Chakravarty ◽  
Sachin M. Deshpande
Keyword(s):  
Size Distribution ◽  
Western Ghats ◽  
Simultaneous Measurements ◽  
Raindrop Size Distribution ◽  
Raindrop Size ◽  
Rain Radar ◽  
The Western Ghats

Rain Droplets Size Distributions Statistical analysis for pre-Monsoon and Monsoon Season over the Western Ghats

2021 ◽  
Author(s):  
Amit Kumar ◽  
Atul Kumar Srivastava ◽  
Kaustav Chakravarty ◽  
Manoj Kumar Srivastava
Keyword(s):  
Statistical Analysis ◽  
Size Distribution ◽  
Western Ghats ◽  
Monsoon Rainfall ◽  
Monsoon Season ◽  
Convective Precipitation ◽  
Raindrop Size Distribution ◽  
Raindrop Size ◽  
The Western Ghats

<p>Four years (2015-2018), Joss-Waldvogel disdrometer (JWD) data are utilized for the statistical analysis of Raindrop size distribution (RSD) of pre-monsoon and monsoon season over the Western Ghats. JWD Instrument installed at High Altitude Cloud Physics Laboratory (HACPL, 17.92°N, 73.66°E), Mahabaleshwar in the core of heavy rainfall region of Western Ghats. Variation in raindrop size distribution characteristics features in pre-monsoon and monsoon season for convective and stratiform precipitation of windward side of Western Ghats analysis, using long-term in-situ JWD instrument data done. Convective and stratiform rainfall classification is based on the number of concentrations of rain droplets and rain rates. Tropical Rainfall Measuring Mission (TRMM) and ERA-Interim data sets are also integrated with disdrometer data to establish microphysical and dynamical features of pre-monsoon and monsoon season rain. Long-term trends of rain droplet size spectra are not studied until now over the Western Ghats.   Rain droplet spectra of pre-monsoon and monsoon seasons show notable differences. The rain droplets of monsoon display considerably higher divergence compared to pre-monsoon rainfall.  Monsoon rainfall has a higher concentration of smaller drops, while pre-monsoon rainfall contains a significantly higher concentration of large droplets. RSD classified on the rain rate demonstrates a higher mass-weighted mean diameter (D<sub>m</sub>) and a lower normalized intercept parameter (log<sub>10</sub>N<sub>w</sub>) in monsoon than winter. Similarly, the Diurnal variation of RSD reveals higher D<sub>m</sub> with a lower value of log<sub>10</sub>N<sub>w</sub> in pre-monsoon season. Also, in both seasons, the higher value of mean D<sub>m</sub> in convective precipitation than stratiform.  Convective activities with increased ground temperature alter RSD in pre-monsoon season rather than monsoon season through droplet classification, evaporation, and collision-coalescence processes.</p>

scholarly journals Statistical characteristics of raindrop size distribution over the Western Ghats of India: wet versus dry spells of the Indian summer monsoon

2021 ◽  
Vol 21 (6) ◽  
pp. 4741-4757
Author(s):  
Uriya Veerendra Murali Krishna ◽  
Subrata Kumar Das ◽  
Ezhilarasi Govindaraj Sulochana ◽  
Utsav Bhowmik ◽  
Sachin Madhukar Deshpande ◽  
...  
Keyword(s):  
Size Distribution ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Diurnal Cycle ◽  
Western Ghats ◽  
Raindrop Size Distribution ◽  
Dry Spells ◽  
Raindrop Size ◽  
The Western Ghats ◽  
Wet Spells

Abstract. The nature of raindrop size distribution (DSD) is analyzed for wet and dry spells of the Indian summer monsoon (ISM) in the Western Ghats (WG) region using Joss–Waldvogel disdrometer (JWD) measurements during the ISM period (June–September) in 2012–2015. The observed DSDs are fitted with a gamma distribution. Observations show a higher number of smaller drops in dry spells and more midsize and large drops in wet spells. 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 very prominent in the wet spells. Results reveal the microphysical characteristics of warm rain during both wet and dry periods. However, the underlying dynamical parameters, such as moisture availability and vertical wind, cause the differences in DSD characteristics. The higher moisture and strong vertical winds can provide sufficient time for the raindrops to grow bigger in wet spells, whereas higher temperature may lead to evaporation and drop breakup processes in dry spells. In addition, the differences in DSD spectra with different rain rates are also observed. The DSD spectra are further analyzed by separating them into stratiform and convective rain types. Finally, an empirical relationship between the slope parameter λ and the shape parameter μ is derived by fitting the quadratic polynomial during wet and dry spells as well as for stratiform and convective types of rain. The μ–λ relations obtained in this work are slightly different compared to previous studies. These differences could be related to different rain microphysics such as collision–coalescence and breakup.

scholarly journals Distribusi Arah Vertikal Butiran Hujan dari Hujan Stratiform di Kototabang dari Pengamatan Micro Rain Radar (MRR)

2019 ◽  
Vol 8 (3) ◽  
pp. 252-259 ◽  
Author(s):  
Ravidho Ramadhan ◽  
Marzuki Marzuki
Keyword(s):  
Size Distribution ◽  
Melting Layer ◽  
Raindrop Size Distribution ◽  
Raindrop Size ◽  
Rain Radar

Distribusi ukuran butiran hujan atau raindrop size distribution (RSD) arah vertikal hujan stratiform dari ketinggian 0,45 km hingga 4,65 km di atas permukaan tanah di Kototabang, Sumatera Barat (0,20o LS; 100,32o BT; 865 m di atas permukaan laut ), telah diteliti melalui pengamatan Micro Rain Radar (MRR) selama Januari 2012 sampai Agustus 2016. RSD dari MRR dimodelkan dengan distribusi gamma dan parameternya didapatkan menggunakan metode momen. Pertumbuhan RSD dari hujan stratiform pada ketinggian 3,9 – 3,4 km sangat kuat untuk semua ukuran butiran, yang menandakan  daerah melting layer di Kototabang. Di bawah daerah melting layer terjadi penurunan konsentrasi butiran berukuran kecil dan peningkatan konsentrasi butiran besar. Hal ini diperkirakan disebabkan oleh proses evaporasi dan updraft pada butiran kecil dan coalescence yang teramati pada hujan stratiform dengan intensitas tinggi. Hal ini juga ditandai dengan perubahan parameter gamma dan koefisien persamaan Z-R (Z=ARb) terhadap penurunan ketinggian. Dengan demikian, asumsi persamaan Z-R yang konstan untuk setiap ketinggian bagi hujan stratiform pada radar meteorologi khususnya di Kototabang kurang akurat.Kata kunci: Hujan stratiform, Kototabang, Micro Rain Radar (MRR), raindrop size distribution (RSD)

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.

scholarly journals Struktur Vertikal Distribusi Butiran Hujan di Kototabang Berdasarkan Pengamatan Micro Rain Radar (MRR)

2016 ◽  
Vol 5 (4) ◽  
pp. 287-296
Author(s):  
Indah Rahayu ◽  
Marzuki Marzuki ◽  
Hiroyuki Hashiguchi ◽  
Toyoshi Shimomai
Keyword(s):  
Size Distribution ◽  
Rain Gauge ◽  
Radar Reflectivity ◽  
Rainfall Rate ◽  
Raindrop Size Distribution ◽  
Raindrop Size ◽  
Rain Radar

Distribusi ukuran butiran hujan atau raindrop size distribution (RDSD) arah vertikal dari ketinggian 0,15 km hingga 4,65 km di Kototabang, Sumatera Barat, telah diteliti melalui pengamatan Micro Rain Radar (MRR) selama Januari-Desember 2012. Intensitas curah hujan (rainfall rate) dari Optical Rain Gauge (ORG) dan RDSD dari Parsivel digunakan untuk menguji kinerja MRR. Pengujian memperlihatkan bahwa MRR berfungsi dengan baik dimana intensitas curah hujan dari ORG berkorelasi dengan baik dengan MRR (r = 0,98) dan RDSD dari MRR secara umum juga memperlihatkan pola dan nilai yang sama dengan yang didapatkan Parsivel.  Selanjutnya, RDSD dari MRR dimodelkan dengan distribusi gamma dan parameternya didapatkan menggunakan metode momen.  Terlihat bahwa pertumbuhan RDSD di Kototabang dari ketinggian 4,65 km hingga 0,15 km sangat kuat yang kemungkinan disebabkan oleh proses tumbukan-penggabungan.  Hal ini ditandai dengan peningkatan konsentrasi butiran berukuran besar dengan penurunan ketinggian.  Peningkatan konsentrasi butiran hujan berukuran besar terhadap penurunan ketinggian berpengaruh kepada parameter-parameter hujan seperti radar reflectivity (Z) dan rainfall rate (R) yang menyebabkan peningkatan koefisien A (Z= ARb) terhadap penurunan ketinggian.  Dengan demikian, penggunaan persamaan Z-R yang konstan untuk setiap ketinggian bagi radar meteorologi di kawasan tropis khususnya Sumatera Barat tidak  tepat.Kata kunci: raindrop size distribution, MRR, Kototabang, distribusi gamma.

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.

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