Plume Geometry

2020 ◽  
Author(s):  
Keyword(s):  
Plume Geometry

scholarly journals Tropical biomass burning smoke plume size, shape, reflectance, and age based on 2001–2009 MISR imagery of Borneo

2012 ◽  
Vol 12 (7) ◽  
pp. 3437-3454 ◽  
Author(s):  
C. S. Zender ◽  
A. G. Krolewski ◽  
M. G. Tosca ◽  
J. T. Randerson
Keyword(s):  
Optical Properties ◽  
Tropical Forests ◽  
Optical Depth ◽  
Biomass Burning ◽  
Single Scattering ◽  
Particle Dispersion ◽  
Hygroscopic Growth ◽  
Smoke Plume ◽  
Fire Emissions ◽  
Plume Geometry

Abstract. Land clearing for crops, plantations and grazing results in anthropogenic burning of tropical forests and peatlands in Indonesia, where images of fire-generated aerosol plumes have been captured by the Multi-angle Imaging SpectroRadiometer (MISR) since 2001. Here we analyze the size, shape, optical properties, and age of distinct fire-generated plumes in Borneo from 2001–2009. The local MISR overpass at 10:30 a.m. misses the afternoon peak of Borneo fire emissions, and may preferentially sample longer plumes from persistent fires burning overnight. Typically the smoke flows with the prevailing southeasterly surface winds at 3–4 m s−1, and forms ovoid plumes whose mean length, height, and cross-plume width are 41 km, 708 m, and 27% of the plume length, respectively. 50% of these plumes have length between 24 and 50 km, height between 523 and 993 m and width between 18% and 30% of plume length. Length and cross-plume width are lognormally distributed, while height follows a normal distribution. Borneo smoke plume heights are similar to previously reported plume heights, yet Borneo plumes are on average nearly three times longer than previously studied plumes. This could be due to sampling or to more persistent fires and greater fuel loads in peatlands than in other tropical forests. Plume area (median 169 km2, with 25th and 75th percentiles at 99 km2 and 304 km2, respectively) varies exponentially with length, though for most plumes a linear relation provides a good approximation. The MISR-estimated plume optical properties involve greater uncertainties than the geometric properties, and show patterns consistent with smoke aging. Optical depth increases by 15–25% in the down-plume direction, consistent with hygroscopic growth and nucleation overwhelming the effects of particle dispersion. Both particle single-scattering albedo and top-of-atmosphere reflectance peak about halfway down-plume, at values about 3% and 10% greater than at the origin, respectively. The initially oblong plumes become brighter and more circular with time, increasingly resembling smoke clouds. Wind speed does not explain a significant fraction of the variation in plume geometry. We provide a parameterization of plume shape that can help atmospheric models estimate the effects of plumes on weather, climate, and air quality. Plume age, the age of smoke furthest down-plume, is lognormally distributed with a median of 2.8 h (25th and 75th percentiles at 1.3 h and 4.0 h), different from the median ages reported in other studies. Intercomparison of our results with previous studies shows that the shape, height, optical depth, and lifetime characteristics reported for tropical biomass burning plumes on three continents are dissimilar and distinct from the same characteristics of non-tropical wildfire plumes.

A note on plume geometry from a tall stack

1981 ◽  
Vol 20 (1) ◽  
pp. 27-34 ◽  
Author(s):  
K. C. Heidorn
Keyword(s):  
Plume Geometry

scholarly journals On the Response of a Buoyant Plume to Downwelling-Favorable Wind Stress

2012 ◽  
Vol 42 (7) ◽  
pp. 1083-1098 ◽  
Author(s):  
Carlos Moffat ◽  
Steven Lentz
Keyword(s):  
Large Fraction ◽  
Bottom Surface ◽  
Total Width ◽  
Buoyant Plume ◽  
Shelf Circulation ◽  
Density Anomaly ◽  
Plume Water ◽  
Small Depth ◽  
Plume Geometry ◽  
Transient Events

Abstract Here, the response of a coastally trapped buoyant plume to downwelling-favorable wind forcing is explored using a simplified two-dimensional numerical model and a prognostic theory for the resulting width, depth, and density anomaly and along-shelf transport of the plume. Consistent with the numerical simulations, the analytical model shows that the wind causes mixing of the plume water and that the forced cross-shelf circulation can also generate significant deepening and surface narrowing, as well as increased along-shelf transport. The response is due to a combination of the purely advective process that leads to the steepening of the isopycnals and the entrainment of ambient water into the plume. The advective component depends on the initial plume geometry: plumes that have a large fraction of their total width in contact with the bottom (“bottom trapped”) suffer relatively small depth and width changes compared to plumes that have a large fraction of their total width detached from the bottom (“surface trapped”). Key theoretical parameters are Wγ/Wα, the ratio of the width of the plume detached from the bottom to the width of the plume in contact with it, and the ratio of the wind-generated mixed layer δe to the initial plume depth hp, which determines the amount of water initially entrained into the plume. The model results also show that the cross-shelf circulation can be strongly influenced by the wind-driven response in combination with the geostrophic shear of the plume. The continuous entrainment into the plume, as well as transient events, is also discussed.

A modified USP induction port to characterize nasal spray plume geometry and predict turbinate deposition under flow

2018 ◽  
Vol 548 (1) ◽  
pp. 305-313 ◽  
Author(s):  
Daniel Moraga-Espinoza ◽  
Zachary Warnken ◽  
Amanda Moore ◽  
Robert O. Williams ◽  
Hugh D.C. Smyth
Keyword(s):  
Nasal Spray ◽  
Spray Plume ◽  
Plume Geometry

scholarly journals Scalings for Submarine Melting at Tidewater Glaciers from Buoyant Plume Theory

2016 ◽  
Vol 46 (6) ◽  
pp. 1839-1855 ◽  
Author(s):  
Donald A. Slater ◽  
Dan N. Goldberg ◽  
Peter W. Nienow ◽  
Tom R. Cowton
Keyword(s):  
Numerical Models ◽  
Greenland Ice Sheet ◽  
Buoyant Plume ◽  
Dynamic Changes ◽  
High Discharge ◽  
Tidewater Glaciers ◽  
Grounding Line ◽  
Plume Geometry ◽  
Rate Discharge ◽  
Point Line

AbstractRapid dynamic changes at the margins of the Greenland Ice Sheet, synchronous with ocean warming, have raised concern that tidewater glaciers can respond sensitively to ocean forcing. Understanding of the processes encompassing ocean forcing nevertheless remains embryonic. The authors use buoyant plume theory to study the dynamics of proglacial discharge plumes arising from the emergence of subglacial discharge into a fjord at the grounding line of a tidewater glacier, deriving scalings for the induced submarine melting. Focusing on the parameter space relevant for high discharge tidewater glaciers, the authors suggest that in an unstratified fjord the often-quoted relationship between total submarine melt volume and subglacial discharge raised to the ⅓ power is appropriate regardless of plume geometry, provided discharge lies below a critical value. In these cases it is then possible to formulate a simple equation estimating total submarine melt volume as a function of discharge, fjord temperature, and calving front height. However, once linear stratification is introduced—as may be more relevant for fjords in Greenland—the total melt rate discharge exponent may be as large as ¾ (⅔) for a point (line) source plume and display more complexity. The scalings provide a guide for more advanced numerical models, inform understanding of the processes encompassing ocean forcing, and facilitate assessment of the variability in submarine melting both in recent decades and under projected atmospheric and oceanic warming.

Monitoring gas production and C O2 injection at the Sleipner field using time-lapse gravimetry

Geophysics ◽  
2008 ◽  
Vol 73 (6) ◽  
pp. WA155-WA161 ◽  
Author(s):  
Håvard Alnes ◽  
Ola Eiken ◽  
Torkjell Stenvold
Keyword(s):  
Simulation Model ◽  
Gravity Data ◽  
Time Lapse ◽  
Average Density ◽  
Gas Production ◽  
Gravity Gradient ◽  
Water Influx ◽  
Vertical Gravity Gradient ◽  
Plume Geometry ◽  
Best Fit

Thirty seafloor gravity stations have been placed above the carbon dioxide [Formula: see text] injection site and producing gas reservoir at the Sleipner Øst Ty field. Gravity and depth measurements from 2002 and 2005 reveal vertical changes of the permanently deployed benchmarks, probably caused by seafloor erosion and biologic activity (fish). The original gravity data have been reprocessed, resulting in slightly different gravity-change values compared with earlier published results. Observed gravity changes are caused by height variances, gas production and water influx in the Ty Formation, and [Formula: see text] injection in the Utsira Formation. Simultaneous matches to models for these effects have been made. The latest simulation model of the Ty Formation was fitted by permitting a scale factor, and the gravity contribution from the [Formula: see text] plume was determined by using the plume geometry as observed in 4D seismic data and varying the average density. The best-fit vertical gravity gradient is [Formula: see text], and the response from the Ty Formation suggests more water influx than expected in the presurvey simulation model. The best-fit average density of [Formula: see text] is [Formula: see text]. Estimates of the reservoir temperature combined with the equation of state for [Formula: see text] indicate an upper bound on [Formula: see text] density of [Formula: see text]. The gravity data suggest a lower bound of [Formula: see text] at 95% confidence.

scholarly journals Simulating the Transport and Dispersal of Volcanic Ash Clouds With Initial Conditions Created by a 3D Plume Model

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhixuan Cao ◽  
Marcus Bursik ◽  
Qingyuan Yang ◽  
Abani Patra
Keyword(s):  
Long Range ◽  
Volcanic Ash ◽  
Initial Conditions ◽  
Source Parameters ◽  
Vertical Direction ◽  
Volcanic Plume ◽  
Plume Model ◽  
Model Based ◽  
Volcanic Source ◽  
Plume Geometry

Volcanic ash transport and dispersion (VATD) models simulate atmospheric transport of ash from a volcanic source represented by parameterized concentration of ash with height. Most VATD models represent the volcanic plume source as a simple line with a parameterized ash emission rate as a function of height, constrained only by a total mass eruption rate (MER) for a given total rise height. However, the actual vertical ash distribution in volcanic plumes varies from case to case, having complex dependencies on eruption source parameters, such as grain size, speed at the vent, vent size, buoyancy flux, and atmospheric conditions. We present here for the first time the use of a three-dimensional (3D) plume model based on conservation laws to represent the ash cloud source without any prior assumption or simplification regarding plume geometry. By eliminating assumed behavior associated with a parameterized plume geometry, the predictive skill of VATD simulations is improved. We use our recently developed volcanic plume model based on a 3D smoothed-particle hydrodynamic Lagrangian method and couple the output to a standard Lagrangian VATD model. We apply the coupled model to the Pinatubo eruption in 1991 to illustrate the effectiveness of the approach. Our investigation reveals that initial particle distribution in the vertical direction, including within the umbrella cloud, has more impact on the long-range transport of ash clouds than does the horizontal distribution. Comparison with satellite data indicates that the 3D model-based distribution of ash particles through the depth of the volcanic umbrella cloud, which is much lower than the observed maximum plume height, produces improved long-range VATD simulations. We thus show that initial conditions have a significant impact on VATD, and it is possible to obtain a better estimate of initial conditions for VATD simulations with deterministic, 3D forward modeling of the volcanic plume. Such modeling may therefore provide a path to better forecasts lessening the need for user intervention, or attempts to observe details of an eruption that are beyond the resolution of any potential satellite or ground-based technique, or a posteriori creating a history of ash emission height via inversion.

scholarly journals Tropical biomass burning smoke plume size, shape, reflectance, and age based on 2001–2009 MISR imagery of Borneo

2011 ◽  
Vol 11 (11) ◽  
pp. 30989-31030
Author(s):  
C. S. Zender ◽  
A. G. Krolewski ◽  
M. G. Tosca ◽  
J. T. Randerson
Keyword(s):  
Optical Properties ◽  
Air Quality ◽  
Tropical Forests ◽  
Optical Depth ◽  
Biomass Burning ◽  
Single Scattering ◽  
Particle Dispersion ◽  
Hygroscopic Growth ◽  
Smoke Plume ◽  
Plume Geometry

Abstract. Land clearing for crops and plantations and grazing results in anthropogenic burning of tropical forests and peatlands in Indonesia, where images of fire-generated aerosol plumes have been captured by the Multi-angle Imaging SpectroRadiometer (MISR) since 2001. Our modeling studies show this smoke increases atmospheric heating, and reduces regional SST and dry-season precipitation, causing a potential feedback that increases drought-stress and air quality problems during El Niño years. Here we analyze the size, shape, optical properties, and age of fire-generated plumes in Borneo from 2001–2009. Most smoke flows with the prevailing southeasterly surface winds at 3–4 m s−1, and forms ovoid plumes whose mean length, height, and cross-plume width are 41 ± 1.4 (mean ± std. error) km, 708 ± 13 m, and 27 ± 0.75% of the plume length, respectively. Borneo smoke plume heights are similar to previously reported plume heights, yet Borneo plumes are nearly three times longer than previously studied plumes, possibly due to more persistent fires and greater fuel loads in peatlands than in other tropical forests. Plume area (median 169 ± 15 km2) varies exponentially with length, though for most plumes a linear relation provides a good approximation. The MISR-estimated plume optical properties involve greater uncertainties than the geometric properties, and show patterns consistent with smoke aging. Optical depth increases by 15–25% in the down-plume direction, consistent with hygroscopic growth and nucleation overwhelming the effects of particle dispersion. Both particle single-scattering albedo and top-of-atmosphere albedo peak about halfway down-plume, at values about 3% and 10% greater than at the origin, respectively. The initially oblong plumes become brighter and more circular with time, increasingly resembling smoke clouds. Wind speed does not explain a significant fraction of the variation in plume geometry. We provide a parameterization of plume shape that can help atmospheric models estimate the effects of plumes on weather, climate, and air quality. Plume age, the age of smoke furthest down-plume, is lognormally distributed with a median of 2.8 ± 0.3 h, significantly different than median ages reported in other studies. Intercomparison of our results with previous studies shows that the shape, height, optical depth, and lifetime characteristics reported for tropical biomass burning plumes on three continents are dissimilar and distinct from the same characteristics of wildfire plumes from the extratropics.

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