scholarly journals Attenuation in melting layer of precipitation

1988 ◽  
Vol 24 (18) ◽  
pp. 1187 ◽  
Author(s):  
W. Klaassen
Keyword(s):  
2009 ◽  
Author(s):  
Paolo Di Girolamo ◽  
Donato Summa ◽  
Rohini Bhawar ◽  
Tatiana Di Iorio ◽  
Geraint Vaughan ◽  
...  

Atmosphere ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 319 ◽  
Author(s):  
Patrick Gatlin ◽  
Walter Petersen ◽  
Kevin Knupp ◽  
Lawrence Carey

Vertical variability in the raindrop size distribution (RSD) can disrupt the basic assumption of a constant rain profile that is customarily parameterized in radar-based quantitative precipitation estimation (QPE) techniques. This study investigates the utility of melting layer (ML) characteristics to help prescribe the RSD, in particular the mass-weighted mean diameter (Dm), of stratiform rainfall. We utilize ground-based polarimetric radar to map the ML and compare it with Dm observations from the ground upwards to the bottom of the ML. The results show definitive proof that a thickening, and to a lesser extent a lowering, of the ML causes an increase in raindrop diameter below the ML that extends to the surface. The connection between rainfall at the ground and the overlying microphysics in the column provide a means for improving radar QPE at far distances from a ground-based radar or close to the ground where satellite-based radar rainfall retrievals can be ill-defined.


2019 ◽  
Vol 8 (3) ◽  
pp. 252-259 ◽  
Author(s):  
Ravidho Ramadhan ◽  
Marzuki Marzuki

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)


2014 ◽  
Vol 11 (7) ◽  
pp. 8845-8877
Author(s):  
M. Frech ◽  
J. Steinert

Abstract. An intense orographic precipitation event is analysed using two polarimetric C-Band radars situated north of the Alps on 5 January 2013. One radar is operated at DWD's meteorological observatory Hohenpeißenberg (MHP, 1006 m a.s.l. – above sea level) and the Memmingen (MEM, 65 km west of MHP, 600 m a.s.l.) radar is part of DWD's operational radar network. The event lasted about 1.5 days and in total 44 mm precipitation was measured at Hohenpeißenberg. Detailed high resolution observation on the vertical structure of this event is obtained through a birdbath scan at 90° elevation which is part of the operational scanning. This scan is acquired every 5 min and provides meteorological profiles at high spatial resolution. In the course of this event, the melting layer (ML) descends until the transition from rain into snow is observed at ground level. This transition from rain into snow is well documented by local weather observers and a present-weather sensor. The orographic precipitation event reveals mesoscale variability above the melting layer which is unexpected from a meteorological point of view. It corresponds to a substantial increase in rain rate at the surface. The performance of the newly developed hydrometeor classification scheme "Hymec" using Memmingen radar data over Hohenpeißenberg is analyzed. The detection in location and timing of the ML agrees well with the Hohenpeißenberg radar data. Considering the size of the Memmingen radar sensing volume, the detected hydrometeor (HM) types are consistent for measurements at or in a ML, even though surface observation indicate for example rain whereas the predominant HM is classified as wet snow. To better link the HM classification with the surface observation, either better thermodynamic input is needed for Hymec or a statistical correction of the HM classification similar to a model output statistics (MOS) approach may be needed.


2008 ◽  
Vol 65 (6) ◽  
pp. 1991-2001 ◽  
Author(s):  
Catherine Heyraud ◽  
Wanda Szyrmer ◽  
Stéphane Laroche ◽  
Isztar Zawadzki

Abstract In this paper a simplified UHF-band backscattering parameterization for individual melting snowflakes is proposed. This parameterization is a function of the density, shape, and melted fraction, and is used here in a brightband bulk modeling study. A 1D bulk model is developed where aggregation and breakup are neglected. Model results are in good agreement with detailed bin-model results and simulate the radar brightband observations well. It is shown the model can be seen as an observation operator that could be introduced into a data assimilation scheme to extract information contained in the radar data measurements.


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