Doppler Radar Observations of Drop-Size Distributions in a Thunderstorm

Sekhon, R. S.; Srivastava, R. C.

doi:10.1175/1520-0469(1971)028<0983:droods>2.0.co;2

Cited by 240 publications

(110 citation statements)

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“…Phys., 5, 2005 www.atmos-chem-phys.org/acp/5/2227/ by raindrops) is parameterised following Slinn (1983) with scavenging coefficients taken from Beard and Grover (1974). The raindrop distribution is assumed to follow the MarshallPalmer distribution (with the sophistication of Sekhon and Srivastava (1971)) and is described with seven geometrically spaced raindrop bins.…”

Section: Microphysical Processesmentioning

confidence: 99%

A global off-line model of size-resolved aerosol microphysics: I. Model development and prediction of aerosol properties

et al. 2005

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Abstract.A GLObal Model of Aerosol Processes (GLOMAP) has been developed as an extension to the TOMCAT 3-D Eulerian off-line chemical transport model. GLOMAP simulates the evolution of the global aerosol size distribution using a sectional two-moment scheme and includes the processes of aerosol nucleation, condensation, growth, coagulation, wet and dry deposition and cloud processing. We describe the results of a global simulation of sulfuric acid and sea spray aerosol. The model captures features of the aerosol size distribution that are well established from observations in the marine boundary layer and free troposphere. Modelled condensation nuclei (CN >3 nm) vary between about 250-500 cm −3 in remote marine boundary layer regions and are generally in good agreement with observations. Modelled continental CN concentrations are lower than observed, which may be due to lack of some primary aerosol sources or the neglect of nucleation mechanisms other than binary homogeneous nucleation of sulfuric acidwater particles. Remote marine CN concentrations increase to around 2000-10 000 cm −3 (at standard temperature and pressure) in the upper troposphere, which agrees with typical observed vertical profiles. Cloud condensation nuclei (CCN) at 0.2% supersaturation vary between about 1000 cm −3 in polluted regions and between 10 and 500 cm −3 in the remote marine boundary layer. New particle formation through sulfuric acid-water binary nucleation occurs predominantly in the upper troposphere, but the model results show that these particles contribute greatly to aerosol concentrations in the marine boundary layer. For this sulfur-sea salt system it is estimated that sea spray emissions account for only ∼10% of CCN in the tropical marine boundary layer, but between 20 and 75% in the mid-latitude Southern Ocean. In a run with only natural sulfate and sea salt emissions the global mean surface CN concentration is more than 60% of that from a run Correspondence to: D. V. Spracklen (dominick@env.leeds.ac.uk) with 1985 anthropogenic sulfur emissions, although the natural emissions comprise only 27% of total sulfur emissions. Southern hemisphere marine boundary layer CN are more than 90% natural in origin, while polluted continental CN are more than 90% anthropogenic in origin, although these numbers will change when other anthropogenic CN sources are included in the model.

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Section: Microphysical Processesmentioning

confidence: 99%

A global off-line model of size-resolved aerosol microphysics: I. Model development and prediction of aerosol properties

et al. 2005

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“…The relationship was produced by theoretical derivations and practical observations [19][20][21][22]. Using this relationship, vertical air velocity can be deduced by subtracting V estimated by radar-measured Z from the radar-measured mean Doppler velocity (V ).…”

Section: Introductionmentioning

confidence: 99%

Retrieving Vertical Air Velocity in Convective Cloud over the Tibetan Plateau from TIPEX-III Cloud Radar Doppler Spectra

Zheng¹,

Liu²,

Zhu³

et al. 2017

Preprint

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Abstract:In the summertime, convections occur frequently over the Tibetan Plateau (TP) because of the large dynamic and thermal effects of the landmass. Measurements of vertical air velocity in convective cloud are useful for advancing our understanding of the dynamic and microphysical mechanisms of clouds and can be used to improve the parameterization of current numerical models. This paper presents a technique for retrieving high-resolution vertical air velocity from convective cloud over the TP, by using Doppler spectra from a vertically pointing Ka-band cloud radar. The method is based on the development of a "smallparticle-traced" idea and the necessary data processing and uses three modes of radar. Spectral broadening corrections, uncertainty estimations, and result merging are used to ensure accurate results. Qualitative analysis of two typical convective cases shows that the retrievals are reliable and agree with the expectant results inferred from other radar measurements. A quantitative retrieval of vertical air motion from a ground-based optical disdrometer is used to preliminarily validate our radar-derived results. The comparison illustrates that while the data trends from the two methods of retrieval are similar, with the updrafts and downdrafts coinciding, cloud radar has a much higher resolution and can reveal the small-scale variation of vertical air motion.

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“…Nevertheless, some relatively recent developments have contributed to the increased interest of the hydrological community in the microstructure of rainfall; we identify, for example, the use of weather radars for estimating the spatial and temporal distribution of rainfall (e.g. Atlas et al, 1973;Sekhon and Srivastava, 1971;Uijlenhoet, 1999) and the attention devoted to understanding processes at the land surface, such as soil detachment and erosion by raindrop impact, infiltration of rain water into the soil, surface runoff and interception by vegetation canopies. In general, these are highly nonlinear processes to which every raindrop can make a significant contribution.…”

Section: Introductionmentioning

confidence: 99%

“…The vertically pointing Doppler radars can also be included in this class (e.g. Atlas et al, 1973;Sekhon and Srivastava, 1971), although this technology lacks the ability to resolve individual raindrops (e.g. Uijlenhoet, 1999).…”

Section: Introductionmentioning

confidence: 99%

Revisiting simple methods to estimate drop size distributions: a novel approach based on infrared thermography

Lima

Silva

Lima

et al. 2015

Journal of Hydrology and Hydromechanics

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Abstract:The infrared thermography has been successfully applied as a tool for high resolution imaging in different hydrological studies. This exploratory experimental study aimed at evaluating the possibility of using infrared thermography to determine the diameter of raindrops. Rain samples are collected on a pre-heated acrylic board, which is exposed to rain during an instant, and thermograms are recorded. The area of the thermal stains ("signatures" of the raindrops) emerging on the board is measured and converted to drop diameters, applying a calibration equation. Diameters of natural raindrops estimated using this technique were compared with laser disdrometer measurements; the Nash-Sutcliffe efficiency coefficient was used for evaluating the match between the resulting histograms of drop size distribution. Results confirm the usefulness of this simple technique for sizing and counting raindrops, although it is unsatisfactory in light rain or drizzle.

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Doppler Radar Observations of Drop-Size Distributions in a Thunderstorm

Cited by 240 publications

References 0 publications

A global off-line model of size-resolved aerosol microphysics: I. Model development and prediction of aerosol properties

A global off-line model of size-resolved aerosol microphysics: I. Model development and prediction of aerosol properties

Retrieving Vertical Air Velocity in Convective Cloud over the Tibetan Plateau from TIPEX-III Cloud Radar Doppler Spectra

Revisiting simple methods to estimate drop size distributions: a novel approach based on infrared thermography

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