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contributor authorPorcù, Federico
contributor authorD’Adderio, Leo Pio
contributor authorProdi, Franco
contributor authorCaracciolo, Clelia
date accessioned2017-06-09T16:55:08Z
date available2017-06-09T16:55:08Z
date copyright2013/04/01
date issued2012
identifier issn0022-4928
identifier otherams-76489.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4218941
description abstractoalescence and breakup of drops are recognized as the main mechanisms determining raindrop size distributions on the ground. Full knowledge of these processes is hindered by the challenging difficulties both in the laboratory and tunnel experiments and during observations in the open air.In real rain breakup is mainly due to collision between drops of different sizes (collisional breakup) and occurs when the collisional kinetic energy (CKE) is not absorbed by the colliding drops. In this work, the authors observe and measure the dependence on altitude of the occurrence of collisional breakup in real rainfall events, and then estimate the corresponding limit terminal velocities of drops and their size when breakup significantly takes place.Data from Pludix, an X-band microwave disdrometer, were collected at three locations at different elevations: collisional breakup position in the power spectrum of Pludix increases toward higher frequencies with increasing altitude. Terminal velocities and sizes of the drops at breakup were determined consequently, with drop sizes resulting in 4.55 ± 0.35, 4.02 ± 0.32, and 3.16 ± 0.3 mm for altitudes of 15, 950, and 3300 m MSL, respectively. The authors computed the CKE of the colliding drops at the breakup, finding an upper limiting value of about 1.22 ? 10?5 J for all three altitudes. This shows that most dominant collisional breakup signature occurs at similar CKE values for all three locations, corresponding to different drop diameters at different altitudes because of the effect of air density on the drop terminal velocity.
publisherAmerican Meteorological Society
titleEffects of Altitude on Maximum Raindrop Size and Fall Velocity as Limited by Collisional Breakup
typeJournal Paper
journal volume70
journal issue4
journal titleJournal of the Atmospheric Sciences
identifier doi10.1175/JAS-D-12-0100.1
journal fristpage1129
journal lastpage1134
treeJournal of the Atmospheric Sciences:;2012:;Volume( 070 ):;issue: 004
contenttypeFulltext


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