Plume Dynamics Research Articles

New insights into mechanisms of material ejection in MALDI mass spectrometry for a wide range of spot sizes

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is widely used for the analysis of large biomolecules in numerous applications. The technique utilizes nanosecond-long laser pulses at various spot sizes to eject and ionize large molecules embedded in a highly absorptive chemical matrix. Despite the methods name, ‘molecular desorption’ from the matrix crystal surface is not the sole mechanism discussed for material ejection in MALDI, but additional ablation of larger clusters has been reported. Here we present results on the influence of laser fluence and spot size on the mechanisms of the initial material ejection in MALDI and subsequent plume development. We used a laser-based postionization (MALDI-2) as well as a complementary photoacoustic method to monitor the material ejection step. The photoacoustic data reveal a quasi-thermal sublimation process up to a transition fluence. Above this threshold fluence additional ablation processes are observed. Complementary investigations on plume dynamics by MALDI-2 showed an ejection of predominantly fast particles for desorption conditions while ablation produces considerably slower ejecta. Additionally the presented results revealed a peculiar influence of the spot size on analyte fragmentation as well as plume development and allows for new insights into the unexplained spot size effect reported for MALDI.

Characteristics of plasma plume in ultrafast laser ablation with a weakly ionized air channel.

We report the influence of femtosecond (fs) laser weakly ionized air channel on characteristics of plasma induced from fs-laser ablation of solid Zr metal target. A novel method to create high temperature, low electron density plasma with intense elemental emission and weak bremsstrahlung emission was demonstrated. Weakly ionized air channel was generated as a result of a non-linear phenomenon. Two-dimensional time-resolved optical-emission images of plasma plumes were taken for plume dynamics analysis. Dynamic physical properties of filament channels were simulated. In particular, we investigated the influence of weakly ionized air channel on the evolution of solid plasma plume. Plasma plume splitting was observed whilst longer weakly ionized air channel formed above the ablation spot. The domination mechanism for splitting is attributed to the long-lived underdense channel created by fs-laser induced weakly ionization of air. The evolutions of atomic/molecular emission intensity, peak broadening, and plasma temperature were analyzed, and the results show that the part of plasma entering weakly ionized air channel features higher initial temperature, lower electron density and faster decay.

Integral models for bubble, droplet, and multiphase plume dynamics in stratification and crossflow

We present the development and validation of a numerical modeling suite for bubble and droplet dynamics of multiphase plumes in the environment. This modeling suite includes real-fluid equations of state, Lagrangian particle tracking, and two different integral plume models: an Eulerian model for a double-plume integral model in quiescent stratification and a Lagrangian integral model for multiphase plumes in stratified crossflows. Here, we report a particle tracking algorithm for dispersed-phase particles within the Lagrangian integral plume model and a comprehensive validation of the Lagrangian plume model for single- and multiphase buoyant jets. The model utilizes literature values for all entrainment and spreading coefficients and has one remaining calibration parameter kappa , which reduces the buoyant force of dispersed phase particles as they approach the edge of a Lagrangian plume element, eventually separating from the plume as it bends over in a crossflow. We report the calibrated form kappa = [(b - r) / b]^4 , where b is the plume half-width, and r is the distance of a particle from the plume centerline. We apply the validated modeling suite to simulate two test cases of a subsea oil well blowout in a stratification-dominated crossflow. These tests confirm that errors from overlapping plume elements in the Lagrangian integral model during intrusion formation for a weak crossflow are negligible for predicting intrusion depth and the fate of oil droplets in the plume. The Lagrangian integral model has the added advantages of being able to account for entrainment from an arbitrary crossflow, predict the intrusion of small gas bubbles and oil droplets when appropriate, and track the pathways of individual bubbles and droplets after they separate from the main plume or intrusion layer.

Influence of River‐Induced Fronts on Hydrocarbon Transport: A Multiplatform Observational Study

AbstractThe Taylor Energy Site is located in the vicinity of the Mississippi Delta region over the Northern Gulf of Mexico (NGoM). Surface oil patches have been persistently observed within this site since 2004, when an oil rig was destroyed by Hurricane Ivan. A multiplatform observational experiment was conducted in April 2017 to investigate, for the first time, the main hydrocarbon pathways from the Taylor Energy Site toward the NGoM continental shelves, and the Gulf interior, under the influence of local and regional physical processes. Results indicate that the Mississippi River (MR)‐induced fronts over the Taylor Energy Site, in combination with local circulation, prevailing winds and broader regional dynamics determine the hydrocarbon transport. The drifters deployed during the field experiment, in tandem with satellite data, drone imagery, wind measurements, and radar‐derived data, efficiently described three major hydrocarbon pathways, associated with MR plume dynamics (downstream/upstream coastal currents) and basin‐wide circulation (offshore pathway). Two different types of drifters, drogued and undrogued, showed clearly different pathways, which suggest potential differences in the expected advection of oil, depending on whether it forms a surface slick or whether it is partially mixed below the surface. The existence of multiple river fronts influenced the fate of oiled waters, preventing the hydrocarbons from reaching the Delta, like a natural boom barrier, trapping and directing the oil either westward or eastward. Thermohaline measurements showed that the MR plume near Taylor was 5–10 m deep, while the clearer ocean was characterized by a 40 m upper ocean homogenous layer.

Entrainment and Energy Transfer Variability Along the Descending Path of the Denmark Strait Overflow Plume

AbstractThe descent of the Denmark Strait overflow plume is an important process in the Atlantic Meridional Overturning Circulation. Downstream of the sill, the plume entrains ambient water, increasing its volume transport. The entrainment and related transfer of energy can be driven by vertical or horizontal turbulent mixing, and varies spatially, as the plume descends, and temporally, as the volume transport at the sill changes. Using over 30 years of profile data, this spatial and temporal variability in the first 200 km downstream of the sill was investigated. Dissipation and entrainment rates were derived from Thorpe scales, and each profile was identified as either a low‐ or high‐transport flow, defined as below or above‐average volume transport at the sill. In the first 175 km flow type explains most of the variability in entrainment and dissipation rates, with high‐transport flow producing order of magnitude higher rates. Sections crossing the plume and yo‐yo casts (continuous profiling) indicate that dissipation and entrainment are likely driven by the formation of shear instabilities in the interfacial layer, when the vertical velocity shear overcomes the stratification. This vertical turbulent mixing explains most of the variability within the first 175 km, suggesting horizontal turbulent mixing processes may not play as important a role in this region. The importance of temporal flow variability means that further improvements to our understanding of plume dynamics in the Denmark Strait will require a novel observational approach to fully account for spatial and temporal contributions.

Experimental study of the convection in a rotating tangent cylinder

This paper experimentally investigates the convection in a rapidly rotating tangent cylinder (TC), for Ekman numbers down to $E=3.36\times 10^{-6}$. The apparatus consists of a hemispherical fluid vessel heated in its centre by a protruding heating element of cylindrical shape. The resulting convection that develops above the heater, i.e. within the TC, is shown to set in for critical Rayleigh numbers and wavenumbers respectively scaling as $Ra_{c}\sim E^{-4/3}$ and $a_{c}\sim E^{-1/3}$ with the Ekman number $E$. Although exhibiting the same exponents as for plane rotating convection, these laws reflect much larger convective plumes at onset. The structure and dynamics of supercritical plumes are in fact closer to those found in solid rotating cylinders heated from below, suggesting that the confinement within the TC induced by the Taylor–Proudman constraint influences convection in a similar way as solid walls would do. There is a further similarity in that the critical modes in the TC all exhibit a slow retrograde precession at onset. In supercritical regimes, the precession evolves into a thermal wind with a complex structure featuring retrograde rotation at high latitude and either prograde or retrograde rotation at low latitude (close to the heater), depending on the criticality and the Ekman number. The intensity of the thermal wind measured by the Rossby number $Ro$ scales as $Ro\simeq 5.33(Ra_{q}^{\ast })^{0.51}$ with the Rayleigh number based on the heat flux $Ra_{q}^{\ast }\in [10^{-9},10^{-6}]$. This scaling is in agreement with heuristic predictions and previous experiments where the thermal wind is determined by the azimuthal curl of the balance between the Coriolis force and buoyancy. Within the range $Ra\in [2\times 10^{7},10^{9}]$ which we explored, we also observe a transition in the heat transfer through the TC from a diffusivity-free regime where $Nu\simeq 0.38E^{2}Ra^{1.58}$ to a rotation-independent regime where $Nu\simeq 0.2Ra^{0.33}$.

Using picosatellites for 4-D imaging of volcanic clouds: Proof of concept using ISS photography of the 2009 Sarychev Peak eruption

Volcanic ash clouds can present an aviation hazard over distances of thousands of kilometres and, to help to mitigate this hazard, advanced numerical models are used to forecast ash dispersion in the atmosphere. However, forecast accuracy is usually limited by uncertainties in initial conditions such as the eruption rate and the vertical distribution of ash injected above the volcano. Here, we demonstrate the potential of the Telematics Earth Observation Mission (TOM) picosatellite formation, due for launch in 2020, to provide valuable information for constraining ash cloud dispersion models through simultaneous image acquisition from three satellites. TOM will carry commercial frame cameras. Using photogrammetric simulations, we show that such data should enable ash cloud heights to be determined with a precision (~30–140 m depending on configuration) comparable to the vertical resolution of lidar observations (30–180 m depending on the cloud height). To support these estimates, we processed photographs taken from the International Space Station of the 2009 Sarychev Peak eruption, as a proxy for TOM imagery. Structure-from-motion photogrammetric software successfully reconstructed the 3-D form of the ascending ash cloud, as well as surrounding cloud layers. Direct estimates of the precision of the ash cloud height measurements, as well as comparisons between independently processed image sets, indicate that a vertical measurement precision of ~200 m was achieved. Image sets acquired at different times captured the plume dynamics and enabled a mean ascent velocity of 14 m s−1 to be estimated for regions above 7 km. In contrast, the uppermost regions of the column (at a measured cloud top height of ~11 km) were not ascending significantly, enabling us to constrain a 1-D plume ascent model, from which estimates for the vent size (50 m) and eruption mass flux (2.6 × 106 kg s−1) could be made. Thus, we demonstrate that nanosatellite imagery has the potential for substantially reducing uncertainties in ash dispersion models by providing valuable information on eruptive conditions.

Dynamics of an atmospheric pressure planar plume with two naked electrodes excited by an alternating current voltage

A large-scale plasma plume has been generated downstream of an argon flow with two naked electrodes excited by an alternating current voltage. Complicated dynamics under various dissipated powers are investigated for the planar plume. Results indicate that, besides the primary oscillations of the applied voltage at 70 kHz, a secondary oscillation is observed for the amplitude envelope of the gas voltage. Furthermore, the secondary oscillation is composed of an increasing amplitude region and a fluctuating amplitude one. With increasing the dissipated power, the duration time of the increasing amplitude region increases, and that of the fluctuating amplitude region decreases until the latter one disappears completely. The secondary oscillation frequency is investigated as a function of the dissipated power and the gas velocity. Detailed waveforms of the gas voltage, the current, and the integrated light emission are investigated for the two regions. Moreover, comprehensive investigations are performed using fast photography over the planar plume, synchronized with simultaneously recorded waveforms. It is found that the secondary oscillation originates from the dynamical movement of a plasma column, which periodically generates in the vicinity of the outlet and disappears at the plume tail.

Heat transport enhancement and scaling law transition in two-dimensional Rayleigh-Bénard convection with rectangular-type roughness

Direct numerical simulations (DNS) of Rayleigh-Bénard convection are performed in two-dimensional (2-D) square cavities with rough top and bottom plates. The roughness is introduced by setting heated/cooled rectangular elements called fins equidistantly onto lower/upper plates. The Rayleigh numbers (Ra) range from 107 to 1010. Different numbers of fins (S) are used with Prandtl number (Pr) fixed to 1. The Pr effect is also investigated for fixed S=8, with Pr varied from 0.71 to 34.1. It is found that in all roughness configurations, the heat transport is significantly enhanced when Ra exceeds a critical value. The power-law scalings of the Nusselt number (Nu) versus Ra keep in change in the studied Ra range for all Pr and S, with most of the exponents within [1/3,1/2], larger than those in smooth cases. In addition, we find Nu increases monotonically with Pr when Pr⩾1 and Ra is moderate for S=8. The dynamics of plumes, the flow structures between the fins and in the bulk, as well as the turbulence dissipation rates are found to be greatly influenced by the presence of fins, which are responsible for the heat transport enhancement, as well as the change in Nu∼Ra power-law scalings.

Comparison of plume dynamics for laser ablated metals: Al and Ti

Emissive plumes from pulsed laser ablation of bulk Ti and Al from KrF laser irradiation at laser fluence up to 3.5 J/cm2 and argon background pressures of 0–1 Torr have been observed using gated intensified charged-coupled device imagery. Mass loss for Ti increases from 0.1 to 0.8 μg/pulse as pulse energy increase from 174 to 282 mJ/pulse (35–170 photons/atom) and decreases by ∼30% as pressure increases from vacuum to 1 Torr. Early plume energies are described by the free expansion velocities of 1.57 ± 0.02 and of 1.81 ± 0.07 cm/μs for Ti and Al, respectively, and up to 90% of the incoming laser energy can be attributed to the Al shock front in the mid-field. The ablation thresholds of 90 ± 27 mJ (1.12 ± 0.34 J/cm2) for Ti and 126 ± 13 mJ (1.58 ± 0.16 J/cm2) for Al also represent 30%–70% of the incident laser energy. The decrease in mass loss at higher pressures is attributed to plasma shielding of the target surface.

Influence of the distance between target surface and focal point on the expansion dynamics of a laser-induced silicon plasma with spatial confinement

Expansion dynamics of a laser-induced plasma plume, with spatial confinement, for various distances between the target surface and focal point were studied by the fast photography technique. A silicon wafer was ablated to induce the plasma with a Nd:YAG laser in an atmospheric environment. The expansion dynamics of the plasma plume depended on the distance between the target surface and focal point. In addition, spatially confined time-resolved images showed the different structures of the plasma plumes at different distances between the target surface and focal point. By analyzing the plume images, the optimal distance for emission enhancement was found to be approximately 6mm away from the geometrical focus using a 10cm focal length lens. This optimized distance resulted in the strongest compression ratio of the plasma plume by the reflected shock wave. Furthermore, the duration of the interaction between the reflected shock wave and the plasma plume was also prolonged.

Discontinuous Galerkin modeling of the Columbia River’s coupled estuary-plume dynamics

The Columbia River (CR) estuary is characterized by high river discharge and strong tides that generate high velocity flows and sharp density gradients. Its dynamics strongly affects the coastal ocean circulation. Tidal straining in turn modulates the stratification in the estuary. Simulating the hydrodynamics of the CR estuary and plume therefore requires a multi-scale model as both shelf and estuarine circulations are coupled. Such a model has to keep numerical dissipation as low as possible in order to correctly represent the plume propagation and the salinity intrusion in the estuary. Here, we show that the 3D baroclinic discontinuous Galerkin finite element model SLIM 3D is able to reproduce the main features of the CR estuary-to-ocean continuum. We introduce new vertical discretization and mode splitting that allow us to model a region characterized by complex bathymetry and sharp density and velocity gradients. Our model takes into account the major forcings, i.e. tides, surface wind stress and river discharge, on a single multi-scale grid. The simulation period covers the end of spring-early summer of 2006, a period of high river flow and strong changes in the wind regime. SLIM 3D is validated with in-situ data on the shelf and at multiple locations in the estuary and compared with an operational implementation of SELFE. The model skill in the estuary and on the shelf indicate that SLIM 3D is able to reproduce the key processes driving the river plume dynamics, such as the occurrence of bidirectional plumes or reversals of the inner shelf coastal currents.

Tidal downscaling from the open ocean to the coast: a new approach applied to the Bay of Biscay

Downscaling physical processes from a large scale to a regional scale 3D model is a recurrent issue in coastal processes studies. The choice of boundary conditions will often greatly influence the solution within the 3D circulation model. In some regions, tides play a key role in coastal dynamics and must be accurately represented.The Bay of Biscay is one of these regions, with highly energetic tides influencing coastal circulation and river plume dynamics. In this study, three strategies are tested to force with barotropic tides a 3D circulation model with a variable horizontal resolution. The tidal forcings, as well as the tidal elevations and currents resulting from the 3D simulations, are compared to tidal harmonics extracted from satellite altimetry and tidal gauges, and tidal currents harmonics obtained from ADCP data.The results show a strong improvement of the M2 solution within the 3D model with a ”tailored” tidal forcing generated on the same grid and bathymetry as the 3D configuration, compared to a global tidal atlas forcing. Tidal harmonics obtained from satellite altimetry data are particularly valuable to assess the performance of each simulation. Comparisons between sea surface height time series, a sea surface salinity database, and daily averaged 2D currents also show a better agreement with this tailored forcing.

Understanding the plume dynamics of explosive super-eruptions

Explosive super-eruptions can erupt up to thousands of km3 of magma with extremely high mass flow rates (MFR). The plume dynamics of these super-eruptions are still poorly understood. To understand the processes operating in these plumes we used a fluid-dynamical model to simulate what happens at a range of MFR, from values generating intense Plinian columns, as did the 1991 Pinatubo eruption, to upper end-members resulting in co-ignimbrite plumes like Toba super-eruption. Here, we show that simple extrapolations of integral models for Plinian columns to those of super-eruption plumes are not valid and their dynamics diverge from current ideas of how volcanic plumes operate. The different regimes of air entrainment lead to different shaped plumes. For the upper end-members can generate local up-lifts above the main plume (over-plumes). These over-plumes can extend up to the mesosphere. Injecting volatiles into such heights would amplify their impact on Earth climate and ecosystems.

Estimating the Cross‐Shelf Export of Riverine Materials: Part 1. General Relationships From an Idealized Numerical Model

AbstractRivers deliver large amounts of terrestrially derived materials (such as nutrients, sediments, and pollutants) to the coastal ocean, but a global quantification of the fate of this delivery is lacking. Nutrients can accumulate on shelves, potentially driving high levels of primary production with negative consequences like hypoxia, or be exported across the shelf to the open ocean where impacts are minimized. Global biogeochemical models cannot resolve the relatively small‐scale processes governing river plume dynamics and cross‐shelf export; instead, river inputs are often parameterized assuming an “all or nothing” approach. Recently, Sharples et al. (2017), https://doi.org/10.1002/2016GB005483 proposed the SP number—a dimensionless number relating the estimated size of a plume as a function of latitude to the local shelf width—as a simple estimator of cross‐shelf export. We extend their work, which is solely based on theoretical and empirical scaling arguments, and address some of its limitations using a numerical model of an idealized river plume. In a large number of simulations, we test whether the SP number can accurately describe export in unforced cases and with tidal and wind forcings imposed. Our numerical experiments confirm that the SP number can be used to estimate export and enable refinement of the quantitative relationships proposed by Sharples et al. We show that, in general, external forcing has only a weak influence compared to latitude and derive empirical relationships from the results of the numerical experiments that can be used to estimate riverine freshwater export to the open ocean.

High-resolution surface salinity maps in coastal oceans based on geostationary ocean color images: quantitative analysis of river plume dynamics

Sea surface salinity (SSS) in coastal oceans is a direct indicator of riverine plumes and provides essential information about the ocean environment and ecosystem, which affects coastal fisheries, aquaculture, and marine harvests. However, to accurately capture SSS patterns in coastal oceans, high temporal and spatial resolutions are required. This paper introduces a methodology to produce high-resolution (~ 500 m) SSS maps for analysis of river plumes in coastal oceans based on hourly chromophoric dissolved organic matter data collected by the Geostationary Ocean Color Imager. Osaka Bay, located in the eastern Seto Inland Sea, was selected as a pilot region. A comparison between the initial estimates and calibrated SSS data showed a substantial decrease in estimation error, by up to 71%, over a wide range of salinity (20–34) using in situ SSS data collected through an automated observation system. Calculating the salinity anomaly based on the SSS map to identify plume areas, we evaluated the impact of a large runoff event induced by a super typhoon on the river plumes. After the plume formed in the estuary, it extended southward to the bay mouth along the southeastern coast. The plume area during the post-typhoon period covered half of the bay, approximately 1.5 times the area during the pre-typhoon period. The post-typhoon, low-SSS period continued for approximately 2 weeks. Our approach can be of practical use for analyzing the dynamics of river plumes in coastal oceans, leading to the development of coastal ocean prediction models related to operational oceanography.

Frazil-ice growth rate and dynamics in mixed layers and sub-ice-shelf plumes

Abstract. The growth of frazil or granular ice is an important mode of ice formation in the cryosphere. Recent advances have improved our understanding of the microphysical processes that control the rate of ice-crystal growth when water is cooled beneath its freezing temperature. These advances suggest that crystals grow much faster than previously thought. In this paper, we consider models of a population of ice crystals with different sizes to provide insight into the treatment of frazil ice in large-scale models. We consider the role of crystal growth alongside the other physical processes that determine the dynamics of frazil ice. We apply our model to a simple mixed layer (such as at the surface of the ocean) and to a buoyant plume under a floating ice shelf. We provide numerical calculations and scaling arguments to predict the occurrence of frazil-ice explosions, which we show are controlled by crystal growth, nucleation, and gravitational removal. Faster crystal growth, higher secondary nucleation, and slower gravitational removal make frazil-ice explosions more likely. We identify steady-state crystal size distributions, which are largely insensitive to crystal growth rate but are affected by the relative importance of secondary nucleation to gravitational removal. Finally, we show that the fate of plumes underneath ice shelves is dramatically affected by frazil-ice dynamics. Differences in the parameterization of crystal growth and nucleation give rise to radically different predictions of basal accretion and plume dynamics, and can even impact whether a plume reaches the end of the ice shelf or intrudes at depth.

Simulation of regimes of convection and plume dynamics by the thermal Lattice Boltzmann Method

We present 2D simulations using the Lattice Boltzmann Method (LBM) of a fluid in a rectangular box being heated from below, and cooled from above. We observe plumes, hot narrow upwellings from the base, and down-going cold chutes from the top. We have varied both the Rayleigh numbers and the Prandtl numbers respectively from Ra=1000 to Ra=1010 , and Pr=1 through Pr=5×104, leading to Rayleigh-Bénard convection cells at low Rayleigh numbers through to vigorous convection and unstable plumes with pronounced vortices and eddies at high Rayleigh numbers. We conduct simulations with high Prandtl numbers up to Pr=50,000 to simulate in the inertial regime. We find for cases when Pr⩾100 that we obtain a series of narrow plumes of upwelling fluid with mushroom heads and chutes of downwelling fluid. We also present simulations at a Prandtl number of 0.7 for Rayleigh numbers varying from Ra=104 through Ra=107.5. We demonstrate that the Nusselt number follows power law scaling of form Nu∼Raγ where γ=0.279±0.002, which is consistent with published results of γ=0.281 in the literature. These results show that the LBM is capable of reproducing results obtained with classical macroscopic methods such as spectral methods, and demonstrate the great potential of the LBM for studying thermal convection and plume dynamics relevant to geodynamics.

Multi-temporal dynamics of suspended particulate matter in a macro-tidal river Plume (the Gironde) as observed by satellite data

The Gironde River plume area is unique in terms of Suspended Particulate Matter (SPM) dynamics. Multiple factors contribute to the variations of SPM at multiple time scales, from river outputs to wind stress, currents and tidal cycles. The formation and evolution of the Maximum Turbidity Zone (MTZ) inside the estuary also plays a significant role. Thus, detailed analyses and monitoring of the region is important for better understanding the mechanisms governing the turbid plume dynamics, for proper future management and monitoring of SPM export from the estuary to the coastal ocean. In this study we use an unprecedented volume of satellite data to capture and better understand the dynamics of the river plume. We combine two types of satellite information in order to achieve these goals: data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensors. The integrated information allows accounting for multiple time scales, i.e. from seasonal to diurnal cycles. We show and parameterize the overall effects of river discharge rates over the plume extension. Seasonal variations are also analyzed and an overall relationship between river discharge rates and plume magnitude is computed. For the first time, we clearly observe and explain the diurnal cycle of SPM dynamics in the river plume. Despite the limited capabilities of the SEVIRI sensor, geostationary data was successfully used to derive such information and results similar to in-situ datasets were obtained. The same patterns are observed, with significant increase in SPM plume during spring/ebb tide periods. Results from our study can be further used to refine sediment transport models and to gain a better perspective on the ecological implications of the sediment output in the continental shelf area.

The Rapid Deployments to Wildfires Experiment (RaDFIRE): Observations from the Fire Zone

AbstractThe Rapid Deployments to Wildfires Experiment (RaDFIRE) was a meteorological field campaign aimed at observing fire–atmosphere interactions during active wildfires. Using a rapidly deployable scanning Doppler lidar, airborne Doppler radar, and a suite of other instruments, the field campaign sampled 21 wildfires from 2013 to 2016 in the western United States. Observations include rotating convective plumes, plume interactions with stable layers and multilayered smoke detrainment, convective plume entrainment processes, smoke-induced density currents, and aircraft in situ observations of developing pyrocumulus. Collectively, these RaDFIRE observations highlight the range of meteorological phenomena associated with wildfires, especially plume dynamics, and will provide a valuable dataset for the modeling community.