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Journal of Geophysical Research. Atmospheres: JGR

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https://www.readbyqxmd.com/read/28955601/analysis-of-aerosol-composition-data-for-western-united-states-wildfires-between-2005-and-2015-dust-emissions-chloride-depletion-and-most-enhanced-aerosol-constituents
#1
Joseph S Schlosser, Rachel A Braun, Trevor Bradley, Hossein Dadashazar, Alexander B MacDonald, Abdulmonam A Aldhaif, Mojtaba Azadi Aghdam, Ali Hossein Mardi, Peng Xian, Armin Sorooshian
This study examines major wildfires in the western United States between 2005 and 2015 to determine which species exhibit the highest percent change in mass concentration on day of peak fire influence relative to preceding nonfire days. Forty-one fires were examined using the Environmental Protection Agency (EPA) Interagency Monitoring of Protected Visual Environments (IMPROVE) data set. Organic carbon (OC) and elemental carbon (EC) constituents exhibited the highest percent change increase. The sharpest enhancements were for the volatile (OC1) and semivolatile (OC2) OC fractions, suggestive of secondary organic aerosol formation during plume transport...
August 27, 2017: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28955600/analysis-of-remotely-sensed-and-surface-data-of-aerosols-and-meteorology-for-the-mexico-megalopolis-area-between-2003-and-2015
#2
Marco Mora, Rachel A Braun, Taylor Shingler, Armin Sorooshian
This paper presents an aerosol characterization study from 2003 to 2015 for the Mexico City Metropolitan Area using remotely sensed aerosol data, ground-based measurements, air mass trajectory modeling, aerosol chemical composition modeling, and reanalysis data for the broader Megalopolis of Central Mexico region. The most extensive biomass burning emissions occur between March and May concurrent with the highest aerosol optical depth, ultraviolet aerosol index, and surface particulate matter (PM) mass concentration values...
August 27, 2017: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28989832/constraints-to-do-realistic-modeling-of-the-electric-field-ahead-of-the-tip-of-a-lightning-leader
#3
Alexander Broberg Skeltved, Nikolai Østgaard, Andrew Mezentsev, Nikolai Lehtinen, Brant Carlson
Several computer models exist to explain the observation of terrestrial gamma-ray flashes (TGFs). Some of these models estimate the electric field ahead of lightning leaders and its effects on electron acceleration and multiplication. In this paper, we derive a new set of constraints to do more realistic modeling. We determine initial conditions based on in situ measurements of electric field and vertical separation between the main charge layers of thunderclouds. A maximum electric field strength of 50 kV/cm at sea level is introduced as the upper constraint for the leader electric field...
August 16, 2017: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28804697/evaluation-of-satellite-and-reanalysis-based-global-net-surface-energy-flux-and-uncertainty-estimates
#4
Chunlei Liu, Richard P Allan, Michael Mayer, Patrick Hyder, Norman G Loeb, Chris D Roberts, Maria Valdivieso, John M Edwards, Pier-Luigi Vidale
The net surface energy flux is central to the climate system yet observational limitations lead to substantial uncertainty. A combination of satellite-derived radiative fluxes at the top of atmosphere adjusted using the latest estimation of the net heat uptake of the Earth system, and the atmospheric energy tendencies and transports from the ERA-Interim reanalysis are used to estimate surface energy flux globally. To consider snowmelt and improve regional realism, land surface fluxes are adjusted through a simple energy balance approach at each grid point...
June 27, 2017: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28603681/methane-emissions-from-the-marcellus-shale-in-southwestern-pennsylvania-and-northern-west-virginia-based-on-airborne-measurements
#5
Xinrong Ren, Dolly L Hall, Timothy Vinciguerra, Sarah E Benish, Phillip R Stratton, Doyeon Ahn, Jonathan R Hansford, Mark D Cohen, Sayantan Sahu, Hao He, Courtney Grimes, Ross J Salawitch, Sheryl H Ehrman, Russell R Dickerson
Natural gas production in the U.S. has increased rapidly over the past decade, along with concerns about methane (CH4) leakage (total fugitive emissions), and climate impacts. Quantification of CH4 emissions from oil and natural gas (O&NG) operations is important for establishing scientifically sound, cost-effective policies for mitigating greenhouse gases. We use aircraft measurements and a mass balance approach for three flight experiments in August and September 2015 to estimate CH4 emissions from O&NG operations in the southwestern Marcellus Shale region...
April 27, 2017: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/29082119/relationships-between-radiation-clouds-and-convection-during-dynamo
#6
Paul E Ciesielski, Richard H Johnson, Xianan Jiang, Yunyan Zhang, Shaocheng Xie
The relationships between radiation, clouds, and convection on an intraseasonal time scale are examined with data taken during the Dynamics of the Madden-Julian Oscillation (MJO) field campaign. Specifically, column-net, as well as vertical profiles of radiative heating rates, computed over Gan Island in the central Indian Ocean (IO) are used along with an objective analysis of large-scale fields to examine three MJO events that occurred during the 3 month period (October to December 2011) over this region...
March 16, 2017: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28516029/the-power-of-vertical-geolocation-of-atmospheric-profiles-from-gnss-radio-occultation
#7
Barbara Scherllin-Pirscher, Andrea K Steiner, Gottfried Kirchengast, Marc Schwärz, Stephen S Leroy
High-resolution measurements from Global Navigation Satellite System (GNSS) radio occultation (RO) provide atmospheric profiles with independent information on altitude and pressure. This unique property is of crucial advantage when analyzing atmospheric characteristics that require joint knowledge of altitude and pressure or other thermodynamic atmospheric variables. Here we introduce and demonstrate the utility of this independent information from RO and discuss the computation, uncertainty, and use of RO atmospheric profiles on isohypsic coordinates-mean sea level altitude and geopotential height-as well as on thermodynamic coordinates (pressure and potential temperature)...
February 16, 2017: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28357174/production-mechanisms-of-leptons-photons-and-hadrons-and-their-possible-feedback-close-to-lightning-leaders
#8
Christoph Köhn, Gabriel Diniz, Muhsin N Harakeh
It has been discussed that lightning flashes emit high-energy electrons, positrons, photons, and neutrons with single energies of several tens of MeV. In the first part of this paper we study the absorption of neutron beams in the atmosphere. We initiate neutron beams of initial energies of 350 keV, 10 MeV, and 20 MeV at source altitudes of 4 km and 16 km upward and downward and see that in all these cases neutrons reach ground altitudes and that the cross-section areas extend to several km(2). We estimate that for terrestrial gamma-ray flashes approximately between 10 and 2000 neutrons per ms and m(2) are possibly detectable at ground, at 6 km, or at 500 km altitude...
January 27, 2017: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28261536/constraints-on-oceanic-methane-emissions-west-of-svalbard-from-atmospheric-in-situ-measurements-and-lagrangian-transport-modeling
#9
I Pisso, C Lund Myhre, S M Platt, S Eckhardt, O Hermansen, N Schmidbauer, J Mienert, S Vadakkepuliyambatta, S Bauguitte, J Pitt, G Allen, K N Bower, S O'Shea, M W Gallagher, C J Percival, J Pyle, M Cain, A Stohl
Methane stored in seabed reservoirs such as methane hydrates can reach the atmosphere in the form of bubbles or dissolved in water. Hydrates could destabilize with rising temperature further increasing greenhouse gas emissions in a warming climate. To assess the impact of oceanic emissions from the area west of Svalbard, where methane hydrates are abundant, we used measurements collected with a research aircraft (Facility for Airborne Atmospheric Measurements) and a ship (Helmer Hansen) during the Summer 2014 and for Zeppelin Observatory for the full year...
December 16, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28239533/comparison-of-the-sawnuc-model-with-cloud-measurements-of-sulphuric-acid-water-nucleation
#10
Sebastian Ehrhart, Luisa Ickes, Joao Almeida, Antonio Amorim, Peter Barmet, Federico Bianchi, Josef Dommen, Eimear M Dunne, Jonathan Duplissy, Alessandro Franchin, Juha Kangasluoma, Jasper Kirkby, Andreas Kürten, Agnieszka Kupc, Katrianne Lehtipalo, Tuomo Nieminen, Francesco Riccobono, Linda Rondo, Siegfried Schobesberger, Gerhard Steiner, António Tomé, Daniela Wimmer, Urs Baltensperger, Paul E Wagner, Joachim Curtius
Binary nucleation of sulphuric acid-water particles is expected to be an important process in the free troposphere at low temperatures. SAWNUC (Sulphuric Acid Water Nucleation) is a model of binary nucleation that is based on laboratory measurements of the binding energies of sulphuric acid and water in charged and neutral clusters. Predictions of SAWNUC are compared for the first time comprehensively with experimental binary nucleation data from the CLOUD chamber at European Organization for Nuclear Research...
October 27, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28066694/ice-residual-properties-in-mixed-phase-clouds-at-the-high-alpine-jungfraujoch-site
#11
Piotr Kupiszewski, Marco Zanatta, Stephan Mertes, Paul Vochezer, Gary Lloyd, Johannes Schneider, Ludwig Schenk, Martin Schnaiter, Urs Baltensperger, Ernest Weingartner, Martin Gysel
Ice residual (IR) and total aerosol properties were measured in mixed-phase clouds (MPCs) at the high-alpine Jungfraujoch research station. Black carbon (BC) content and coating thickness of BC-containing particles were determined using single-particle soot photometers. The ice activated fraction (IAF), derived from a comparison of IR and total aerosol particle size distributions, showed an enrichment of large particles in the IR, with an increase in the IAF from values on the order of 10(-4) to 10(-3) for 100 nm (diameter) particles to 0...
October 27, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/29082118/in-situ-and-space-based-observations-of-the-kelud-volcanic-plume-the-persistence-of-ash-in-the-lower-stratosphere
#12
Jean-Paul Vernier, T Duncan Fairlie, Terry Deshler, Murali Natarajan, Travis Knepp, Katie Foster, Frank G Wienhold, Kristopher M Bedka, Larry Thomason, Charles Trepte
Volcanic eruptions are important causes of natural variability in the climate system at all time scales. Assessments of the climate impact of volcanic eruptions by climate models almost universally assume that sulfate aerosol is the only radiatively active volcanic material. We report satellite observations from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite after the eruption of Mount Kelud (Indonesia) on 13 February 2014 of volcanic materials in the lower stratosphere...
September 27, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/27867787/interannual-variation-of-springtime-biomass-burning-in-indochina-regional-differences-associated-atmospheric-dynamical-changes-and-downwind-impacts
#13
Wan-Ru Huang, Sheng-Hsiang Wang, Ming-Cheng Yen, Neng-Huei Lin, Parichart Promchote
During March and April, widespread burning occurs across farmlands in Indochina in preparation for planting at the monsoon onset. The resultant aerosols impact the air quality downwind. In this study, we investigate the climatic aspect of the interannual variation of springtime biomass burning in Indochina and its correlation with air quality at Mt. Lulin in Taiwan using long-term (2005-2015) satellite and global reanalysis data. Based on empirical orthogonal function (EOF) analysis, we find that the biomass burning activities vary with two geographical regions: northern Indochina (the primary EOF mode) and southern Indochina (the secondary EOF mode)...
September 16, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/27840780/recent-amplification-of-the-north-american-winter-temperature-dipole
#14
Deepti Singh, Daniel L Swain, Justin S Mankin, Daniel E Horton, Leif N Thomas, Bala Rajaratnam, Noah S Diffenbaugh
During the winters of 2013-2014 and 2014-2015, anomalously warm temperatures in western North America and anomalously cool temperatures in eastern North America resulted in substantial human and environmental impacts. Motivated by the impacts of these concurrent temperature extremes and the intrinsic atmospheric linkage between weather conditions in the western and eastern United States, we investigate the occurrence of concurrent "warm-West/cool-East" surface temperature anomalies, which we call the "North American winter temperature dipole...
September 16, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/27867786/aerosol-lidar-observations-of-atmospheric-mixing-in-los-angeles-climatology-and-implications-for-greenhouse-gas-observations
#15
John Ware, Eric A Kort, Phil DeCola, Riley Duren
Atmospheric observations of greenhouse gases provide essential information on sources and sinks of these key atmospheric constituents. To quantify fluxes from atmospheric observations, representation of transport-especially vertical mixing-is a necessity and often a source of error. We report on remotely sensed profiles of vertical aerosol distribution taken over a 2 year period in Pasadena, California. Using an automated analysis system, we estimate daytime mixing layer depth, achieving high confidence in the afternoon maximum on 51% of days with profiles from a Sigma Space Mini Micropulse LiDAR (MiniMPL) and on 36% of days with a Vaisala CL51 ceilometer...
August 27, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/27708991/using-a-multiwavelength-suite-of-microwave-instruments-to-investigate-the-microphysical-structure-of-deep-convective-cores
#16
A Battaglia, K Mroz, Tim Lang, F Tridon, S Tanelli, Lin Tian, Gerald M Heymsfield
Due to the large natural variability of its microphysical properties, the characterization of solid precipitation is a longstanding problem. Since in situ observations are unavailable in severe convective systems, innovative remote sensing retrievals are needed to extend our understanding of such systems. This study presents a novel technique able to retrieve the density, mass, and effective diameter of graupel and hail in severe convection through the combination of airborne microwave remote sensing instruments...
August 27, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/27867785/lightning-mapping-array-flash-detection-performance-with-variable-receiver-thresholds
#17
Vanna C Chmielewski, Eric C Bruning
This study characterizes Lightning Mapping Array performance for networks that participated in the Deep Convective Clouds and Chemistry field program using new Monte Carlo and curvature matrix model simulations. These open-source simulation tools are readily adapted to real-time operations or detailed studies of performance. Each simulation accounted for receiver threshold and location, as well as a reference distribution of source powers and flash sizes based on thunderstorm observations and the mechanics of station triggering...
July 27, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/27867784/on-the-sensitivity-of-the-diurnal-cycle-in-the-amazon-to-convective-intensity
#18
Kyle F Itterly, Patrick C Taylor, Jason B Dodson, Ahmed B Tawfik
Climate and reanalysis models contain large water and energy budget errors over tropical land related to the misrepresentation of diurnally forced moist convection. Motivated by recent work suggesting that the water and energy budget is influenced by the sensitivity of the convective diurnal cycle to atmospheric state, this study investigates the relationship between convective intensity, the convective diurnal cycle, and atmospheric state in a region of frequent convection-the Amazon. Daily, 3-hourly satellite observations of top of atmosphere (TOA) fluxes from Clouds and the Earth's Radiant Energy System Ed3a SYN1DEG and precipitation from Tropical Rainfall Measuring Mission 3B42 data sets are collocated with twice daily Integrated Global Radiosonde Archive observations from 2002 to 2012 and hourly flux tower observations...
July 27, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/27867783/convective-and-large-scale-mass-flux-profiles-over-tropical-oceans-determined-from-synergistic-analysis-of-a-suite-of-satellite-observations
#19
Hirohiko Masunaga, Zhengzhao Johnny Luo
A new, satellite-based methodology is developed to evaluate convective mass flux and large-scale total mass flux. To derive the convective mass flux, candidate profiles of in-cloud vertical velocity are first constructed with a simple plume model under the constraint of ambient sounding and then narrowed down to the solution that matches satellite-derived cloud top buoyancy. Meanwhile, the large-scale total mass flux is provided separately from satellite soundings by a method developed previously. All satellite snapshots are sorted into a composite time series that delineates the evolution of a vigorous and organized convective system...
July 16, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/27774368/radio-emissions-from-double-rhessi-tgfs
#20
Andrew Mezentsev, Nikolai Østgaard, Thomas Gjesteland, Kjetil Albrechtsen, Nikolai Lehtinen, Martino Marisaldi, David Smith, Steven Cummer
A detailed analysis of Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) terrestrial gamma ray flashes (TGFs) is performed in association with World Wide Lightning Location Network (WWLLN) sources and very low frequency (VLF) sferics recorded at Duke University. RHESSI clock offset is evaluated and found to experience changes on the 5 August 2005 and 21 October 2013, based on the analysis of TGF-WWLLN matches. The clock offsets were found for all three periods of observations with standard deviations less than 100 μs...
July 16, 2016: Journal of Geophysical Research. Atmospheres: JGR
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