8 research outputs found
New York - New Jersey job recovery expected to continue in 1998
The pattern of employment recovery in the New York-New Jersey region is expected to remain unbroken in 1998, despite a slight slowing of job growth.Employment - New York (State) ; Employment - New Jersey ; Federal Reserve District, 2nd
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Ship-based measurements of ice nuclei concentrations over the Arctic, Atlantic, Pacific and Southern oceans
Ambient concentrations of ice-forming particles measured during ship expeditions are collected and summarised with the aim of determining the spatial distribution and variability in ice nuclei in oceanic regions. The presented data from literature and previously unpublished data from over 23 months of ship-based measurements stretch from the Arctic to the Southern Ocean and include a circumnavigation of Antarctica. In comparison to continental observations, ship-based measurements of ambient ice nuclei show 1 to 2 orders of magnitude lower mean concentrations. To quantify the geographical variability in oceanic areas, the concentration range of potential ice nuclei in different climate zones is analysed by meridionally dividing the expedition tracks into tropical, temperate and polar climate zones. We find that concentrations of ice nuclei in these meridional zones follow temperature spectra with similar slopes but vary in absolute concentration. Typically, the frequency with which specific concentrations of ice nuclei are observed at a certain temperature follows a log-normal distribution. A consequence of the log-normal distribution is that the mean concentration is higher than the most frequently measured concentration. Finally, the potential contribution of ship exhaust to the measured ice nuclei concentration on board research vessels is analysed as function of temperature. We find a sharp onset of the influence at approximately 36 C but none at warmer temperatures that could bias ship-based measurements. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License
The study of atmospheric ice-nucleating particles via microfluidically generated droplets
Ice-nucleating particles (INPs) play a significant role in the climate and hydrological cycle by triggering ice formation in supercooled clouds, thereby causing precipitation and affecting cloud lifetimes and their radiative properties. However, despite their importance, INP often comprise only 1 in 10Âłâ10ⶠambient particles, making it difficult to ascertain and predict their type, source, and concentration. The typical techniques for quantifying INP concentrations tend to be highly labour-intensive, suffer from poor time resolution, or are limited in sensitivity to low concentrations. Here, we present the application of microfluidic devices to the study of atmospheric INPs via the simple and rapid production of monodisperse droplets and their subsequent freezing on a cold stage. This device offers the potential for the testing of INP concentrations in aqueous samples with high sensitivity and high counting statistics. Various INPs were tested for validation of the platform, including mineral dust and biological species, with results compared to literature values. We also describe a methodology for sampling atmospheric aerosol in a manner that minimises sampling biases and which is compatible with the microfluidic device. We present results for INP concentrations in air sampled during two field campaigns: (1) from a rural location in the UK and (2) during the UKâs annual Bonfire Night festival. These initial results will provide a route for deployment of the microfluidic platform for the study and quantification of INPs in upcoming field campaigns around the globe, while providing a benchmark for future lab-on-a-chip-based INP studies
Supporting scanning transmission electron microscopy (STEM) data for manuscript titled "Observations of ice nucleating particles in the free troposphere from western U.S. wildfires"
Images, elemental maps, and energy dispersive x-ray spectra, sizing data and categorizations made on the basis of these data are assembled in this archive, which is associated with the above-noted publication. Data describe atmospheric particles collected within or around wildfire plumes from the NSF/NCAR C-130 aircraft during Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption, and Nitrogen (WE-CAN), under support of the National Science Foundation Atmospheric and Geospace Sciences award number 1650786. Based from Boise, ID, maps of the WE-CAN research flights will be published in the submitted publication reference listed at the end of this file. Particle collections were made onto 3-mm diameter transmission electron microscope supports (200 mesh) made of Cu or Ni, and coated with C-formvar films. Collections, as fully described in the publication, represent total particles in a size class from 0.13 to 0.55 microns (using an impactor system) from two different wildfire plume (so-called Sugarloaf fire, research flight 15) during two different plume penetrations (RF15A and RF15C), and ice nucleating particles (INPs) collected/integrated over a number of plume passes. The INPs were collected as activated ice crystals within the Colorado State University (CSU) continuous flow diffusion chamber (CFDC), simulating freezing under supercooled clouds conditions (cf., publication for details). Drs. Cynthia Twohy (NWRA) and Darin Toohey (University of Colorado) oversaw ambient particle collections. Dr. Paul DeMott, Dr. Ezra Levin, and Mr. Kevin Barry oversaw INP collections. Ambient plume particles and INPs processed in the CFDC were both collected from a solid diffuser inlet system on the NSF/NCAR C-130, and represent wildfire particles at ages of 1-2.5 hours aging. INPs were limited in size entering the CFDC at 2.5 microns, although the majority of these were in the same size range as the total particles. STEM data were collected at the Colorado State University Analytical Resources Core â Imaging and Surface Science facility. Dr. Roy Geiss (CSU Chemistry) conducted STEM analyses.Wildfires in the western U.S. are large sources of particulate matter, and the area burned by wildfires is predicted to increase in the future. Some particles released from wildfires can affect cloud formation by serving as ice nucleating particles (INPs). INPs have numerous impacts on cloud radiative properties and precipitation development. Wildfires are potentially important sources of INPs, as indicated from previous measurements, but their abundance in the free troposphere has not been quantified. The Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption, and Nitrogen (WE-CAN) campaign sampled free tropospheric immersion-freezing INPs from smoke plumes near their source and downwind, along with widespread aged smoke. The results indicate an enhancement of INPs in smoke plumes relative to out-of-plume background air, but the magnitude of enhancement was both temperature and fire dependent. The majority of INPs were inferred to be predominately organic in composition with some contribution from biological sources at modest supercooling, and contributions from minerals at deeper supercooling. A fire involving primarily sagebrush shrubland and aspen forest fuels had the highest INP concentrations measured in the campaign, which is partially attributed to the INP characteristics of lofted, uncombusted plant material. Electron microscopy analysis of INPs also indicated tarballs present in this fire. Parameterization of the plume INP data on a per-unit-aerosol surface area basis confirmed that smoke is not an efficient source of INPs. Nevertheless, the high numbers of particles released from, and ubiquity of western U.S. wildfires in summertime, regionally elevate INP concentrations in the free troposphere.This work was supported by the National Science Foundation, Award #AGS-1650786, AGS-1650288, National Science Foundation Graduate Research Fellowship Grant No. 006784, and NOAA Climate Program Office's Atmospheric Chemistry, Carbon Cycle, and Climate program grant NA17OAR4310010
Ship-based measurements of ice nuclei concentrations over the Arctic, Atlantic, Pacific and Southern oceans
Ambient concentrations of ice-forming particles measured during ship expeditions are collected and summarised with the aim of determining the spatial distribution and variability in ice nuclei in oceanic regions. The presented data from literature and previously unpublished data from over 23 months of ship-based measurements stretch from the Arctic to the Southern Ocean and include a circumnavigation of Antarctica. In comparison to continental observations, ship-based measurements of ambient ice nuclei show 1 to 2 orders of magnitude lower mean concentrations. To quantify the geographical variability in oceanic areas, the concentration range of potential ice nuclei in different climate zones is analysed by meridionally dividing the expedition tracks into tropical, temperate and polar climate zones. We find that concentrations of ice nuclei in these meridional zones follow temperature spectra with similar slopes but vary in absolute concentration. Typically, the frequency with which specific concentrations of ice nuclei are observed at a certain temperature follows a log-normal distribution. A consequence of the log-normal distribution is that the mean concentration is higher than the most frequently measured concentration. Finally, the potential contribution of ship exhaust to the measured ice nuclei concentration on board research vessels is analysed as function of temperature. We find a sharp onset of the influence at approximately â36ââC but none at warmer temperatures that could bias ship-based measurements
Sea2Cloud: from biogenic emission fluxes to cloud properties in the South West Pacific
International audienceThe goal of the Sea2Cloud project is to study the interplay between surface oceanbiogeochemical and physical properties, fluxes to the atmosphere and ultimately their impacton cloud formation under minimal direct anthropogenic influence. Here we present aninterdisciplinary approach, combining atmospheric physics and chemistry with marinebiogeochemistry, during a voyage between 41 and 47°S in March 2020. In parallel to ambientmeasurements of atmospheric composition and seawater biogeochemical properties, wedescribe semi-controlled experiments to characterize nascent sea spray properties andnucleation from gas-phase biogenic emissions. The experimental framework for studying theimpact of the predicted evolution of ozone concentration in the Southern Hemisphere is alsodetailed. After describing the experimental strategy, we present the oceanic and meteorologicalcontext including provisional results on atmospheric thermodynamics, composition, and fluxmeasurements. In situ measurements and flux studies were carried out on different biologicalcommunities by sampling surface seawater from subantarctic, subtropical and frontal watermasses. Air-Sea-Tanks (ASIT) were used to quantify biogenic emissions of trace gases underrealistic environmental conditions, with nucleation observed in association with biogenicseawater emissions. Sea spray continuously generated produced sea spray fluxes of 34% oforganic matter by mass, of which 4% particles had fluorescent properties, and which sizedistribution ressembled the one found in clean sectors of the Southern Ocean. The goal ofSea2Cloud is to generate realistic parameterizations of emission flux dependences of tracegases and nucleation precursors, sea spray, cloud condensation nuclei and ice nuclei usingseawater biogeochemistry, for implementation in regional atmospheric model