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About: Thunderstorm is a(n) research topic. Over the lifetime, 5672 publication(s) have been published within this topic receiving 135125 citation(s).

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Abstract: A two-dimensional, time-dependent cloud model has been used to simulate a moderate intensity thunderstorm for the High Plains region. Six forms of water substance (water vapor, cloud water, cloud ice, rain, snow and hail, i.e., graupel) are simulated. The model utilizes the “bulk water” microphysical parameterization technique to represent the precipitation fields which are all assumed to follow exponential size distribution functions. Autoconversion concepts are used to parameterize the collision-coalescence and collision-aggregation processes. Accretion processes involving the various forms of liquid and solid hydrometeors are simulated in this model. The transformation of cloud ice to snow through autoconversion (aggregation) and Bergeron process and subsequent accretional growth or aggregation to form hail are simulated. Hail is also produced by various contact mechanisms and via probabilistic freezing of raindrops. Evaporation (sublimation) is considered for all precipitation particles outsi...

3,031 citations

Journal ArticleDOI
Abstract: This paper presents a range of applications of the Regional Atmospheric Modeling System (RAMS), a comprehensive mesoscale meterological modeling system. Applications discussed in this paper include large eddy simulations (LES) and simulations of thunderstorms, cumulus fields, mesoscale convective systems, mid-latitude cirrus clouds, winter storms, mechanically- and thermally-forced mesoscale systems, and mesoscale atmospheric disperision. A summary of current RAMS options is also presented. Improvements to RAMS currently underway include refinements to the cloud radiation, cloud microphysics, cumulus, and surface soil/vegetative parameterization schemes, the parallelization of the code, development of a more versatile visualization capability, and research into meso-α-scale cumulus parameterization.

1,661 citations

Journal ArticleDOI
27 Feb 2004-Science
TL;DR: Heavy smoke from forest fires in the Amazon was observed to reduce cloud droplet size and so delay the onset of precipitation, which affects the water cycle, the pollution burden of the atmosphere, and the dynamics of atmospheric circulation.
Abstract: Heavy smoke from forest fires in the Amazon was observed to reduce cloud droplet size and so delay the onset of precipitation from 1.5 kilometers above cloud base in pristine clouds to more than 5 kilometers in polluted clouds and more than 7 kilometers in pyro-clouds. Suppression of low-level rainout and aerosol washout allows transport of water and smoke to upper levels,where the clouds appear “smoking” as they detrain much of the pollution. Elevating the onset of precipitation allows invigoration of the updrafts,causing intense thunderstorms,large hail,and greater likelihood for overshooting cloud tops into the stratosphere. There,detrained pollutants and water vapor would have profound radiative impacts on the climate system. The invigorated storms release the latent heat higher in the atmosphere. This should substantially affect the regional and global circulation systems. Together,these processes affect the water cycle,the pollution burden of the atmosphere,and the dynamics of atmospheric circulation. Several hundred thousand deforestation and agricultural fires burn in Amazonia during the dry season each year, covering vast areas with dense smoke (1, 2). The smoke’s radiative impact suppresses surface heating and evaporation and stabilizes the lower troposphere. In turn, this suppresses the formation of convective clouds and precipitation and thus slows down the hydrological cycle (3). The microphysical effects of the aerosols on clouds and precipitation are no less important but have until now only been inferred from modeling and satellite observations. Convective clouds forming in smoky air show substantially reduced droplet size compared to that of similar clouds in clean air (4), with a mean satelliteretrieved effective droplet radius of 9 m in smoky clouds compared to 14 mi n clean clouds (5). This reduction of cloud droplet size by smoke is associated with an inhibition of the onset of precipitation radar echoes up to heights of 6.5 km, compared to 3 km in smoke-free clouds (6, 7). Here, we report in situ measurements for

1,260 citations

Journal ArticleDOI
Abstract: Imagine you are in the last stages of typing your thesis, the year is 1980, and it's a hot, hazy summer afternoon, a thunderstorm brews on the horizon. Tense and tired, you have forgotten to save the document on your hard disk. Suddenly, lightning strikes! Your computer shuts down. Your final chapter is lost.

1,119 citations

Journal ArticleDOI
Abstract: of uncertainty for the OTD global totals represents primarily the uncertainty (and variability) in the flash detection efficiency of the instrument The OTD measurements have been used to construct lightning climatology maps that demonstrate the geographical and seasonal distribution of lightning activity for the globe An analysis of this annual lightning distribution confirms that lightning occurs mainly over land areas, with an average land/ocean ratio of 10:1 The Congo basin, which stands out year-round, shows a peak mean annual flash density of 80 fl km 2 yr 1 in Rwanda, and includes an area of over 3 million km 2 exhibiting flash densities greater than 30 fl km 2 yr 1 (the flash density of central Florida) Lightning is predominant in the northern Atlantic and western Pacific Ocean basins year-round where instability is produced from cold air passing over warm ocean water Lightning is less frequent in the eastern tropical Pacific and Indian Ocean basins where the air mass is warmer A dominant Northern Hemisphere summer peak occurs in the annual cycle, and evidence is found for a tropically driven semiannual cycle INDEX TERMS: 3304 Meteorology and Atmospheric Dynamics: Atmospheric electricity; 3309 Meteorology and Atmospheric Dynamics: Climatology (1620); 3324 Meteorology and Atmospheric Dynamics: Lightning; 3394 Meteorology and Atmospheric Dynamics: Instruments and techniques;

996 citations

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No. of papers in the topic in previous years