Rain microphysical features as observed from ground based radar and disdrometer at a tropical location
01 Jan 2015-pp 1-4
TL;DR: In this article, the rain phases have been classified into stratiform and convective on the basis of bright band signature in the rain rate profile of the micro rain radar and the rain drop size distributions exhibit distinguishable variations for the two types of rain.
Abstract: Tropical region experiences a variety of rainfall types throughout the year. The rain can vary from stratiform to convective even within a single event. The rain parameters have been separately investigated for stratiform and convective cases. The rain phases have been classified into stratiform and convective on the basis of bright band signature in the rain rate profile of the micro rain radar. The rain drop size distributions exhibit discernible difference for stratiform and convective cases. The drop size distribution parameters consequently demonstrate distinguishable variations for the two types of rain.
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TL;DR: In this article, the effects of variations in the shape or breadth of the drop size distribution (DSD) on rainfall parameters were derived for rainfall rate, liquid water content W, and median volume diameter D(O) in terms of Z(DR), Z(H), and size distribution dependent factors.
Abstract: A measurement technique employing the differential reflectivity factor Z(DR) and the horizontal polarization reflectivity factor Z(H) is the basis of the present study of the effects of variations in the shape or breadth of the drop size distribution (DSD) on rainfall parameters. Theoretical expressions are derived for rainfall rate, liquid water content W, and median volume diameter D(O) in terms of Z(DR), Z(H), and size distribution-dependent factors. The latter calculations assume backscattering cross sections for oblate, nonoscillating raindrops falling in still air with equilibrium shapes. These expressions are used to quantitatively assess the effects of changes in DSD breadth on values of R, W, and D(O) deduced from Z(DR) and Z(H).
87 citations
TL;DR: In this article, the microstructure of rain has been studied with observations using a vertical looking Micro Rain Radar (MRR) at Ahmedabad (23.06°N, 72.62°E), a tropical location in the Indian region.
61 citations
"Rain microphysical features as obse..." refers background in this paper
...5 mm with an integration time of 30 second [9]....
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...Bright band indicates the presence of melting layer in startiform events [1, 9]....
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TL;DR: In this article, a linear interpolation between calibration points was applied, and only single peaks were seen in this first, recalibrated dataset. But, field evidence for multiple peak equilibrium distributions obtained in numerical models should be reconsidered.
Abstract: Peaks in number density observed by many authors using Joss-Waldvogel disdrometers are almost certainly due to the manner in which a best-fit curve was chosen to represent the calibration data. The extreme sensitivity to small changes in the calibration curve was demonstrated with extensive observations of Malaysian tropical rain, which for best-fit calibrations showed multiple peaks; however, when a linear interpolation between calibration points was applied, only single peaks were seen in this first, recalibrated dataset. Hence, field evidence for multiple peak equilibrium distributions obtained in numerical models should be reconsidered. On the other hand, the rainfall and radar reflectivity, calculated from best fits, differ by less than 4% from that based on linear interpolation between calibration points.
53 citations
TL;DR: In this article, the authors investigated the characteristics of convective and stratiform precipitation over the tropical and sub-tropical areas based on the measurements of Tropical Rainfall Measuring Mission's (TRMM) Precipitation Radar (PR) from 1998 to 2007.
Abstract: Climatic characteristics of convective and stratiform precipitation over the Tropical and Subtropical areas are investigated based on the measurements of Tropical Rainfall Measuring Mission’s (TRMM) Precipitation Radar (PR) from 1998 to 2007. Results indicate that convective precipitation are distributed mainly over the Intertropical Convergence Zone (ITCZ), the South Pacific Convergence Zone (SPCZ), the Asian Monsoon Region, regions between the South America and the Mid-America, and the Tropical Africa where the frequencies lie between 1% and 2%. But in four seasons, total area fractions of convective precipitation frequencies less than 1% all exceed 85%. The frequencies of stratiform precipitation are much higher than those of convective precipitation, and total area fractions of stratiform precipitation frequencies >1% are over 55% during four seasons. However, frequencies of the two rain types show not only remarkable regionality, but also distinct seasonal variations. Conditional rain rates of convective precipitation range from 6 to 14 mm/h whereas those of stratiform precipitation are smaller than 4 mm/h. Meanwhile, rain tops of convective precipitation are higher than those of stratiform precipitation. The mean profiles of the two rain types show significant latitudinal dependency. And the seasonal variations of precipitation profiles are displayed mainly in the variations of rain tops. The frequencies and conditional rain rates of both rain types over ocean are higher than those over land, but rain tops are just the opposite. Moreover, the seasonal variations of both rain types over ocean are weaker than those over land because of the different stable states of underlying surfaces.
38 citations
TL;DR: In this article, a dataset on raindrop size distribution (DSD) gathered in a coastal site of the Alagoas state in northeastern Brazil is used to analyze some differences between continental and maritime rainfall parameters.
Abstract: A dataset on raindrop size distribution (DSD) gathered in a coastal site of the Alagoas state in northeastern Brazil is used to analyze some differences between continental and maritime rainfall parameters. The dataset is divided into two subsets. One is composed of rainfall systems coming from the continent and moving eastward (i.e., offshore), representing the continental subset. The other is composed of rainfall systems that developed over the sea and are moving westward (i.e., inshore), representing the maritime subset. The mean conditional rain rate (i.e., for rain rate R > 0) is found to be higher for maritime (4.6 mm h−1) than for continental (3.2 mm h−1) conditions. The coefficient of variation of the conditional rain rate is lower for the maritime (1.75) than for the continental (2.25) subset. The continental and maritime DSDs display significant differences. For drop diameter D smaller than about 2 mm, the number of drops is higher for maritime rain than for continental rain. This revers...
38 citations
"Rain microphysical features as obse..." refers background in this paper
...This phenomenon demonstrates [3, 7] that these peaks are entirely instrument related....
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