We have combined aircraft and airborne Doppler radar observations to show that microinsects in the atmospheric convective boundary layer (CBL) are concentrated in rather welldeÞned plumes, that these plumes are generally found in thermals of rising air, and that the insects in those plumes oppose the updrafts at a rate that increases as the updrafts become stronger. In this paper, a simple nume...

[1] Aircraft-based measurements of the water-soluble fraction of fine PM organic carbon (WSOC) and inorganic salt composition in the Atlanta, GA region were conducted in the summer of 2004. Five notable plumes of SO2, apparently from coal-fired power plants, were intercepted, and had NH4 /SO4 2 molar ratios ranging from approximately 0.8 to 1.4 compared to molar ratios near 2 outside of the plu...

The emissions of selected hydrocarbons from in-use commercial aircraft at a major airport in the United States were characterized using proton-transfer reaction mass spectrometry (PTR-MS) and tunable infrared differential absorption spectroscopy (TILDAS) to probe the composition of diluted exhaust plumes downwind. The emission indices for formaldehyde, acetaldehyde, benzene, and toluene, as wel...

Chlorinated solvents in the subsurface are a widespread problem with thousands of impacted sites in the United States. A large body of literature exists that evaluates treatment of chlorinated solvents using granular zero valent iron, which has been shown to treat chlorinated solvents via reductive dechlorination. Much of this literature is conducted within the context of permeable reactive bar...

This paper compares measurements of gaseous and particulate emissions from a wide range of biomassburning plumes intercepted by the NASA DC-8 research aircraft during the three phases of the ARCTAS-2008 experiment: ARCTAS-A, based out of Fairbanks, Alaska, USA (3 April to 19 April 2008); ARCTAS-B based out of Cold Lake, Alberta, Canada (29 June to 13 July 2008); and ARCTASCARB, based out of Pal...

[1] Hydration and partial melting along subducting slabs can trigger Rayleigh-Taylor-like instabilities. We use 3-D petrological-thermomechanical numerical simulations to investigate small-scale convection and hydrous, partially molten, cold plumes formed in the mantle wedge in response to slab dehydration. The simulations were carried out with the I3ELVIS code, which is based on a multigrid ap...

Mantle plumes are hypothetical hot, narrow mantle upwellings that are often invoked to explain hotspot volcanism with unusual geophysical and geochemical characteristics. The mantle plume is a well-established geological structure in computer modeling and laboratory experiments but an undisputed seismic detection of one has yet to be made. Vertically continuous low shear velocity anomalies in t...

We examine concurrent measurements of CN (size > 8 nm), NO, and NOy in the upper troposphere over the North Atlantic during the SONEX Experiment (Oct.-Nov., 1997). High CN and NOy observations are attributed largely to the enhancement in convective outflow. Using the ratio of NO/NOy as a chemical clock, we estimate that dilution of convective high-CN plumes is rapid (on a time scale of < 2 days...

We investigated the expansion features of femtosecond laser generated tungsten nanoparticle plumes in vacuum. Fast gated images showed distinct two components expansion features, viz., plasma and nanoparticle plumes, separated by time of appearance. The persistence of plasma and nanoparticle plumes are 500 ns and 100 ls, respectively, and propagating with velocities differed by 25 times. The es...

Carbon and tungsten have been radiated by 3ω-YAG laser in the power density range from 2 to 12J/cm/pulse in a laboratory setup with the main objective of investigating the behavior of cluster/aerosol formation from colliding ablation plumes. Direct ion mass spectrometry of colliding carbon plumes has identified Cn-clusters including C, C2,C3,C4 and C5. The formation of these Cn-cluster ions has...