[ { "id": "authors:9hpem-j7y68", "collection": "authors", "collection_id": "9hpem-j7y68", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150306-130344201", "type": "article", "title": "IN-SYNC. II. Virial Stars from Subvirial Cores\u2014the Velocity Dispersion of Embedded Pre-main-sequence Stars in NGC 1333", "author": [ { "family_name": "Foster", "given_name": "Jonathan B.", "clpid": "Foster-J-B" }, { "family_name": "Cottaar", "given_name": "Michiel", "clpid": "Cottaar-M" }, { "family_name": "Covey", "given_name": "Kevin R.", "orcid": "0000-0001-6914-7797", "clpid": "Covey-K-R" }, { "family_name": "Arce", "given_name": "H\u00e9ctor G.", "orcid": "0000-0001-5653-7817", "clpid": "Arce-H-G" }, { "family_name": "Meyer", "given_name": "Michael R.", "orcid": "0000-0003-1227-3084", "clpid": "Meyer-M-R" }, { "family_name": "Nidever", "given_name": "David L.", "clpid": "Nidever-D-L" }, { "family_name": "Stassun", "given_name": "Keivan G.", "orcid": "0000-0002-3481-9052", "clpid": "Stassun-K-G" }, { "family_name": "Tan", "given_name": "Jonathan C.", "clpid": "Tan-Jonathan-C" }, { "family_name": "Chojnowski", "given_name": "S. Drew", "clpid": "Chojnowski-S-D" }, { "family_name": "Da Rio", "given_name": "Nicola", "clpid": "Da-Rio-N" }, { "family_name": "Flaherty", "given_name": "Kevin M.", "clpid": "Flaherty-K-M" }, { "family_name": "Rebull", "given_name": "Luisa", "orcid": "0000-0001-6381-515X", "clpid": "Rebull-L-M" }, { "family_name": "Frinchaboy", "given_name": "Peter M.", "clpid": "Frinchaboy-P-M" }, { "family_name": "Majewski", "given_name": "Steven R.", "orcid": "0000-0003-2025-3147", "clpid": "Majewski-S-R" }, { "family_name": "Skrutskie", "given_name": "Michael", "clpid": "Skrutskie-M-F" }, { "family_name": "Wilson", "given_name": "John C.", "clpid": "Wilson-J-C" }, { "family_name": "Zasowski", "given_name": "Gail", "clpid": "Zasowski-G" } ], "abstract": "The initial velocity dispersion of newborn stars is a major unconstrained aspect of star formation theory. Using near-infrared spectra obtained with the APOGEE spectrograph, we show that the velocity dispersion of young (1-2 Myr) stars in NGC 1333 is 0.92 \u00b1 0.12 km s^(\u20131) after correcting for measurement uncertainties and the effect of binaries. This velocity dispersion is consistent with the virial velocity of the region and the diffuse gas velocity dispersion, but significantly larger than the velocity dispersion of the dense, star-forming cores, which have a subvirial velocity dispersion of 0.5 km s^(\u20131). Since the NGC 1333 cluster is dynamically young and deeply embedded, this measurement provides a strong constraint on the initial velocity dispersion of newly formed stars. We propose that the difference in velocity dispersion between stars and dense cores may be due to the influence of a 70 \u03bcG magnetic field acting on the dense cores or be the signature of a cluster with initial substructure undergoing global collapse.", "doi": "10.1088/0004-637X/799/2/136", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2015-02-01", "series_number": "2", "volume": "799", "issue": "2", "pages": "Art. No. 136" }, { "id": "authors:j7dez-nc534", "collection": "authors", "collection_id": "j7dez-nc534", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PETapj08", "type": "article", "title": "New Young Brown Dwarfs in the Orion Molecular Cloud 2/3 Region", "author": [ { "family_name": "Peterson", "given_name": "Dawn E.", "clpid": "Peterson-D-E" }, { "family_name": "Megeath", "given_name": "S. T.", "orcid": "0000-0001-7629-3573", "clpid": "Megeath-S-T" }, { "family_name": "Luhman", "given_name": "K. L.", "clpid": "Luhman-K-L" }, { "family_name": "Pipher", "given_name": "J. L.", "clpid": "Pipher-J-L" }, { "family_name": "Stauffer", "given_name": "J. R.", "orcid": "0000-0003-3595-7382", "clpid": "Stauffer-J-R" }, { "family_name": "Barrado y Navascu\u00e9s", "given_name": "D.", "clpid": "Barrado-y-Navascu\u00e9s-D" }, { "family_name": "Wilson", "given_name": "J. C.", "clpid": "Wilson-J-C" }, { "family_name": "Skrutskie", "given_name": "M. F.", "clpid": "Skrutskie-M-F" }, { "family_name": "Nelson", "given_name": "M. J.", "clpid": "Nelson-M-J" }, { "family_name": "Smith", "given_name": "J. D.", "orcid": "0000-0003-1545-5078", "clpid": "Smith-J-D-T" } ], "abstract": "Forty new low-mass members with spectral types ranging from M4 to M9 have been confirmed in the Orion Molecular Cloud (OMC) 2/3 region. Through deep, I-, z'-, J-, H-, and K-band photometry of a 20' \u00d7 20' field in OMC 2/3, we selected brown dwarf candidates for follow-up spectroscopy. Low-resolution far-red and near-infrared spectra were obtained for the candidates, and 19 young brown dwarfs in the OMC 2/3 region are confirmed. They exhibit spectral types of M6.5-M9, corresponding to approximate masses of 0.075-0.015 M\u2609 using the evolutionary models of Baraffe et al. At least one of these bona fide young brown dwarfs has strong H\u03b1 emission, indicating that it is actively accreting. In addition, we confirm 21 new low-mass members with spectral types of M4-M6, corresponding to approximate masses of 0.35-0.10 M\u2609 in OMC 2/3. By comparing pre-main-sequence tracks to the positions of the members in the H-R diagram, we find that most of the brown dwarfs are less than 1 Myr, but find a number of low-mass stars with inferred ages greater than 3 Myr. The discrepancy in the stellar and substellar ages is due to our selection of only low-luminosity sources; however, the presence of such objects implies the presence of an age spread in the OMC 2/3 region. We discuss possible reasons for this apparent age spread.", "doi": "10.1086/590527", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2008-09-20", "series_number": "1", "volume": "685", "issue": "1", "pages": "313-332" }, { "id": "authors:91ys3-h3n90", "collection": "authors", "collection_id": "91ys3-h3n90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091130-140121274", "type": "article", "title": "A Spitzer Infrared Spectrograph Spectral Sequence of M, L, and T Dwarfs", "author": [ { "family_name": "Cushing", "given_name": "Michael C.", "orcid": "0000-0001-7780-3352", "clpid": "Cushing-M-C" }, { "family_name": "Roellig", "given_name": "Thomas L.", "clpid": "Roellig-T-L" }, { "family_name": "Marley", "given_name": "Mark S.", "orcid": "0000-0002-5251-2943", "clpid": "Marley-M-S" }, { "family_name": "Saumon", "given_name": "D.", "clpid": "Saumon-D" }, { "family_name": "Leggett", "given_name": "S. K.", "clpid": "Leggett-S-K" }, { "family_name": "Kirkpatrick", "given_name": "J. Davy", "orcid": "0000-0003-4269-260X", "clpid": "Kirkpatrick-J-D" }, { "family_name": "Wilson", "given_name": "John C.", "clpid": "Wilson-J-C" }, { "family_name": "Sloan", "given_name": "G. C.", "clpid": "Sloan-G-C" }, { "family_name": "Mainzer", "given_name": "Amy K.", "clpid": "Mainzer-A-K" }, { "family_name": "Van-Cleve", "given_name": "Jeff E.", "clpid": "Van-Cleve-J-E" }, { "family_name": "Houck", "given_name": "James R.", "clpid": "Houck-J-R" } ], "abstract": "We present a low-resolution (R \u2261 \u03bb/\u0394\u03bb \u2248 90), 5.5-38 \u03bcm spectral sequence of a sample of M, L, and T dwarfs obtained with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. The spectra exhibit prominent absorption bands of H_2O at 6.27 \u03bcm, CH_4 at 7.65 \u03bcm, and NH_3 at 10.5 \u03bcm and are relatively featureless at \u03bb \u2273 15 \u03bcm. Three spectral indices that measure the strengths of these bands are presented; H_2O absorption features are present throughout the MLT sequence, while the CH_4 and NH_3 bands first appear at roughly the L/T transition. Although the spectra are, in general, qualitatively well matched by synthetic spectra that include the formation of spatially homogeneous silicate and iron condensate clouds, the spectra of the mid-type L dwarfs show an unexpected flattening from roughly 9 to 11 \u03bcm. We hypothesize that this may be a result of a population of small silicate grains that are not predicted in the cloud models. The spectrum of the peculiar T6 dwarf 2MASS J0937+2931 is suppressed from 5.5 to 7.5 \u03bcm relative to typical T6 dwarfs and may be a consequence of its mildly metal-poor/high surface gravity atmosphere. Finally, we compute bolometric luminosities of a subsample of the M, L, and T dwarfs by combining the IRS spectra with previously published 0.6-4.1 \u03bcm spectra and find good agreement with the values of Golimowski et al., who use L'- and M'-band photometry to account for the flux emitted at \u03bb > 2.5 \u03bcm.", "doi": "10.1086/505637", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2006-09-01", "volume": "648", "pages": "614-628" }, { "id": "authors:11h3b-9z605", "collection": "authors", "collection_id": "11h3b-9z605", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-171117048", "type": "article", "title": "Anvil glaciation in a deep cumulus updraught over Florida simulated with the Explicit Microphysics Model. I: Impact of various nucleation processes", "author": [ { "family_name": "Phillips", "given_name": "Vaughan T. J.", "clpid": "Phillips-V-T-J" }, { "family_name": "Andronache", "given_name": "Constantin", "clpid": "Andronache-C" }, { "family_name": "Sherwood", "given_name": "Steven C.", "clpid": "Sherwood-S-C" }, { "family_name": "Bansemer", "given_name": "Aaron", "clpid": "Bansemer-A" }, { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-W-C" }, { "family_name": "DeMott", "given_name": "Paul J.", "clpid": "DeMott-P-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Heymsfield", "given_name": "Andy", "clpid": "Heymsfield-A" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Poellot", "given_name": "Micheal", "clpid": "Poellot-M" }, { "family_name": "Rissman", "given_name": "Tracey A.", "clpid": "Rissman-T-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "VanReken", "given_name": "Tim", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-T-M" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Wilson", "given_name": "James C.", "clpid": "Wilson-J-C" } ], "abstract": "Simulations of a cumulonimbus cloud observed in the Cirrus Regional Study of Tropical Anvils and Cirrus Layers\u2013Florida Area Cirrus Experiment (CRYSTAL-FACE) with an advanced version of the Explicit Microphysics Model (EMM) are presented. The EMM has size-resolved aerosols and predicts the time evolution of sizes, bulk densities and axial ratios of ice particles. Observations by multiple aircraft in the troposphere provide inputs to the model, including observations of the ice nuclei and of the entire size distribution of condensation nuclei.\n\nHomogeneous droplet freezing is found to be the source of almost all of the ice crystals in the anvil updraught of this particular model cloud. Most of the simulated droplets that freeze to form anvil crystals appear to be nucleated by activation of aerosols far above cloud base in the interior of the cloud ('secondary' or 'in-cloud' droplet nucleation). This is partly because primary droplets formed at cloud base are invariably depleted by accretion before they can reach the anvil base in the updraught, which promotes an increase with height of the average supersaturation in the updraught aloft. More than half of these aerosols, activated far above cloud base, are entrained into the updraught of this model cloud from the lateral environment above about 5 km above mean sea level. This confirms the importance of remote sources of atmospheric aerosol for anvil glaciation.\n\nOther nucleation processes impinge indirectly upon the anvil glaciation by modifying the concentration of supercooled droplets in the upper levels of the mixed-phase region. For instance, the warm-rain process produces a massive indirect impact on the anvil crystal concentration, because it determines the mass of precipitation forming in the updraught. It competes with homogeneous freezing as a sink for cloud droplets. The effects from turbulent enhancement of the warm-rain process and from other nucleation processes on the anvil ice properties are assessed.", "doi": "10.1256/qj.04.85", "issn": "0035-9009", "publisher": "Wiley", "publication": "Quarterly Journal of the Royal Meteorological Society", "publication_date": "2005-07", "series_number": "609", "volume": "131", "issue": "609", "pages": "2019-2046" }, { "id": "authors:9g512-z8y35", "collection": "authors", "collection_id": "9g512-z8y35", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141120-071526447", "type": "article", "title": "Evidence for the Predominance of Mid-Tropospheric Aerosols as Subtropical Anvil Cloud Nuclei", "author": [ { "family_name": "Fridlind", "given_name": "Ann M.", "clpid": "Fridlind-A-M" }, { "family_name": "Ackerman", "given_name": "Andrew S.", "clpid": "Ackerman-A-S" }, { "family_name": "Jensen", "given_name": "Eric J.", "clpid": "Jensen-E-J" }, { "family_name": "Heymsfield", "given_name": "Andrew J.", "clpid": "Heymsfield-A-J" }, { "family_name": "Poellot", "given_name": "Michael R.", "clpid": "Poellot-M-R" }, { "family_name": "Stevens", "given_name": "David E.", "clpid": "Stevens-D-E" }, { "family_name": "Wang", "given_name": "Donghai", "clpid": "Wang-Donghai" }, { "family_name": "Miloshevich", "given_name": "Larry M.", "clpid": "Miloshevich-L-M" }, { "family_name": "Baumgardner", "given_name": "Darrel", "clpid": "Baumgardner-D" }, { "family_name": "Lawson", "given_name": "R. Paul", "clpid": "Lawson-R-P" }, { "family_name": "Wilson", "given_name": "James C.", "clpid": "Wilson-J-C" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "VanReken", "given_name": "Timothy M.", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-T-M" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Rissman", "given_name": "Tracey A.", "clpid": "Rissman-T-A" } ], "abstract": "NASA's recent Cirrus Regional Study of Tropical Anvils and Cirrus Layers\u2013Florida Area Cirrus Experiment focused on anvil cirrus clouds, an important but poorly understood element of our climate system. The data obtained included the first comprehensive measurements of aerosols and cloud particles throughout the atmospheric column during the evolution of multiple deep convective storm systems. Coupling these new measurements with detailed cloud simulations that resolve the size distributions of aerosols and cloud particles, we found several lines of evidence indicating that most anvil crystals form on mid-tropospheric rather than boundary-layer aerosols. This result defies conventional wisdom and suggests that distant pollution sources may have a greater effect on anvil clouds than do local sources.", "doi": "10.1126/science.1094947", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2004-04-30", "series_number": "5671", "volume": "304", "issue": "5671", "pages": "718-722" }, { "id": "authors:2f6hh-1m737", "collection": "authors", "collection_id": "2f6hh-1m737", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140624-094548081", "type": "article", "title": "Quantitative constraints on the atmospheric chemistry of nitrogen oxides: An analysis along chemical coordinates", "author": [ { "family_name": "Cohen", "given_name": "R. C.", "orcid": "0000-0001-6617-7691", "clpid": "Cohen-R-C" }, { "family_name": "Perkins", "given_name": "K. K.", "clpid": "Perkins-K-K" }, { "family_name": "Koch", "given_name": "L. C.", "clpid": "Koch-L-C" }, { "family_name": "Stimpfle", "given_name": "R. M.", "clpid": "Stimpfle-R-M" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Hanisco", "given_name": "T. F.", "orcid": "0000-0001-9434-8507", "clpid": "Hanisco-T-F" }, { "family_name": "Lanzendorf", "given_name": "E. J.", "clpid": "Lanzendorf-E-J" }, { "family_name": "Bonne", "given_name": "G. P.", "clpid": "Bonne-G-P" }, { "family_name": "Voss", "given_name": "P. B.", "clpid": "Voss-P-B" }, { "family_name": "Salawitch", "given_name": "R. J.", "clpid": "Salawitch-R-J" }, { "family_name": "Del Negro", "given_name": "L. A.", "clpid": "Del-Negro-L-A" }, { "family_name": "Wilson", "given_name": "J. C.", "clpid": "Wilson-J-C" }, { "family_name": "McElroy", "given_name": "C. T.", "clpid": "McElroy-C-T" }, { "family_name": "Bui", "given_name": "T. P.", "clpid": "Bui-T-P" } ], "abstract": "In situ observations Of NO_2, NO, NO_y, ClONO_2, OH, O_3, aerosol surface area, spectrally resolved solar radiation, pressure and temperature obtained from the ER-2 aircraft during the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) experiments are used to examine the factors controlling the fast photochemistry connecting NO and NO_2 and the slower chemistry connecting NO_x and HNO_3. Our analysis uses \"chemical coordinates\" to examine gradients of the difference between a model and precisely calibrated measurements to provide a quantitative assessment of the accuracy of current photochemical models. The NO/NO_2 analysis suggests that reducing the activation energy for the NO+O_3 reaction by 1.7 kJ/mol will improve model representation of the temperature dependence of the NO/NO_2 ratio in the range 215\u2013235 K. The NO_x/HNO_3 analysis shows that systematic errors in the relative rate coefficients used to describe NO_x loss by the reaction OH + NO_2 \u2192 HNO_3 and by the reaction set NO_2 + O_3 \u2192 NO_3; NO_2 + NO_3 \u2192 N_(2)O_5; N_(2)O_5 + H_(2)O \u2192 2HNO_3 are in error by +8.4% (+30/\u221245%) (OH+NO_2 too fast) in models using the Jet Propulsion Laboratory 1997 recommendations [DeMore et al., 1997]. Models that use recommendations for OH+NO2 and OH+HNO_3 based on reanalysis of recent and past laboratory measurements are in error by 1.2% (+30/\u221245%) (OH+NO_2 too slow). The +30%/\u221245% error limit reflects systematic uncertainties, while the statistical uncertainty is 0.65%. This analysis also shows that the POLARIS observations only modestly constrain the relative rates of the major NO_x production reactions HNO3 + OH \u2192 H_(2)O + NO_3 and HNO_3 + h\u03bd \u2192 OH + NO_2. Even under the assumption that all other aspects of the model are perfect, the POLARIS observations only constrain the rate coefficient for OH+HNO_3 to a range of 65% around the currently recommended value.", "doi": "10.1029/2000JD900290", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2000-10-16", "series_number": "D19", "volume": "105", "issue": "D19", "pages": "24283-24304" }, { "id": "authors:zmy0k-kpb71", "collection": "authors", "collection_id": "zmy0k-kpb71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140624-094924798", "type": "article", "title": "Ozone destruction and production rates between spring and autumn in the Arctic stratosphere", "author": [ { "family_name": "Fahey", "given_name": "D. W.", "clpid": "Fahey-D-W" }, { "family_name": "Gao", "given_name": "R. S.", "clpid": "Gao-R-S" }, { "family_name": "Del Negro", "given_name": "L. A.", "clpid": "Del-Negro-L-A" }, { "family_name": "Keim", "given_name": "E. R.", "clpid": "Keim-E-R" }, { "family_name": "Kawa", "given_name": "S. R.", "clpid": "Kawa-S-R" }, { "family_name": "Salawitch", "given_name": "R. J.", "clpid": "Salawitch-R-J" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Hanisco", "given_name": "T. F.", "orcid": "0000-0001-9434-8507", "clpid": "Hanisco-T-F" }, { "family_name": "Lanzendorf", "given_name": "E. J.", "clpid": "Lanzendorf-E-J" }, { "family_name": "Perkins", "given_name": "K. K.", "clpid": "Perkins-K-K" }, { "family_name": "Lloyd", "given_name": "S. A.", "clpid": "Lloyd-S-A" }, { "family_name": "Swartz", "given_name": "W. H.", "clpid": "Swartz-W-H" }, { "family_name": "Proffitt", "given_name": "M. H.", "clpid": "Proffitt-M-H" }, { "family_name": "Margitan", "given_name": "J. J.", "clpid": "Margitan-J-J" }, { "family_name": "Wilson", "given_name": "J. C.", "clpid": "Wilson-J-C" }, { "family_name": "Stimpfle", "given_name": "R. M.", "clpid": "Stimpfle-R-M" }, { "family_name": "Cohen", "given_name": "R. C.", "orcid": "0000-0001-6617-7691", "clpid": "Cohen-R-C" }, { "family_name": "McElroy", "given_name": "C. T.", "clpid": "McElroy-C-T" }, { "family_name": "Webster", "given_name": "C. R.", "clpid": "Webster-C-R" }, { "family_name": "Loewenstein", "given_name": "M.", "clpid": "Loewenstein-M" }, { "family_name": "Elkins", "given_name": "J. W.", "clpid": "Elkins-J-W" }, { "family_name": "Bui", "given_name": "T. P.", "clpid": "Bui-T-P" } ], "abstract": "In situ measurements of radical and long-lived species were made in the lower Arctic stratosphere (18 to 20 km) between spring and early autumn in 1997. The measurements include O_3, ClO, OH, HO_2, NO, NO_2, N_(2)O, CO, and overhead O_3. A photochemical box model constrained by these and other observations is used to compute the diurnally averaged destruction and production rates of O3 in this region. The rates show a strong dependence on solar exposure and ambient O_3. Total destruction rates, which reach 19%/month in summer, reveal the predominant role of NO_x and HO_x catalytic cycles throughout the period. Production of O_3 is significant only in midsummer air parcels. A comparison of observed O_3 changes with destruction rates and transport effects indicates the predominant role of destruction in spring and an increased role of transport by early autumn.", "doi": "10.1029/2000GL011404", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2000-09-01", "series_number": "17", "volume": "27", "issue": "17", "pages": "2605-2608" }, { "id": "authors:fknm1-hj355", "collection": "authors", "collection_id": "fknm1-hj355", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120926-135147447", "type": "article", "title": "Discovery of a Bright Field Methane (T-Type) Brown Dwarf by 2MASS", "author": [ { "family_name": "Burgasser", "given_name": "Adam J.", "orcid": "0000-0002-6523-9536", "clpid": "Burgasser-A-J" }, { "family_name": "Wilson", "given_name": "John C.", "clpid": "Wilson-J-C" }, { "family_name": "Kirkpatrick", "given_name": "J. Davy", "orcid": "0000-0003-4269-260X", "clpid": "Kirkpatrick-J-D" }, { "family_name": "Skrutskie", "given_name": "Michael F.", "clpid": "Skrutskie-M-F" }, { "family_name": "Colonno", "given_name": "Michael R.", "clpid": "Colonno-M-R" }, { "family_name": "Enos", "given_name": "Alan T.", "clpid": "Enos-A-T" }, { "family_name": "Smith", "given_name": "J. D.", "orcid": "0000-0003-1545-5078", "clpid": "Smith-J-D-T" }, { "family_name": "Henderson", "given_name": "Charles P.", "clpid": "Henderson-C-P" }, { "family_name": "Gizis", "given_name": "John E.", "orcid": "0000-0002-8916-1972", "clpid": "Gizis-J-E" }, { "family_name": "Brown", "given_name": "Michael E.", "orcid": "0000-0002-8255-0545", "clpid": "Brown-M-E" }, { "family_name": "Houck", "given_name": "James R.", "clpid": "Houck-J-R" } ], "abstract": "We report the discovery of a bright (J = 13.83 \u00b1 0.03) methane brown dwarf, or T dwarf, by the Two Micron All Sky Survey. This object, 2MASSI J0559191-140448, is the first brown dwarf identified by the newly commissioned CorMASS instrument mounted on the Palomar 60 inch (1.5 m) telescope. Near-infrared spectra from 0.9 to 2.35 \u03bcm show characteristic CH_4 bands at 1.1, 1.3, 1.6, and 2.2 \u03bcm, which are significantly shallower than those seen in other T dwarfs discovered to date. Coupled with the detection of an FeH band at 0.9896 \u03bcm and two sets of K I doublets at J band, we propose that 2MASS J0559-14 is a warm T dwarf, close to the transition between L and T spectral classes. The brightness of this object makes it a good candidate for detailed investigation over a broad wavelength regime and at higher resolution.", "doi": "10.1086/301475", "issn": "0004-6256", "publisher": "American Astronomical Society", "publication": "Astronomical Journal", "publication_date": "2000-08", "series_number": "2", "volume": "120", "issue": "2", "pages": "1100-1105" }, { "id": "authors:1ex4h-cvp13", "collection": "authors", "collection_id": "1ex4h-cvp13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140718-090035893", "type": "article", "title": "A comparison of observations and model simulations of NO_x/NO_y in the lower stratosphere", "author": [ { "family_name": "Gao", "given_name": "R. S.", "clpid": "Gao-R-S" }, { "family_name": "Fahey", "given_name": "D. W.", "clpid": "Fahey-D-W" }, { "family_name": "Del Negro", "given_name": "L. A.", "clpid": "Del-Negro-L-A" }, { "family_name": "Donnelly", "given_name": "S. G.", "clpid": "Donnelly-S-G" }, { "family_name": "Keim", "given_name": "E. R.", "clpid": "Keim-E-R" }, { "family_name": "Neuman", "given_name": "J. A.", "clpid": "Neuman-J-A" }, { "family_name": "Teverovskaia", "given_name": "E.", "clpid": "Teverovskaia-E" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Hanisco", "given_name": "T. F.", "orcid": "0000-0001-9434-8507", "clpid": "Hanisco-T-F" }, { "family_name": "Lanzendorf", "given_name": "E. J.", "clpid": "Lanzendorf-E-J" }, { "family_name": "Proffitt", "given_name": "M. H.", "clpid": "Proffitt-M-H" }, { "family_name": "Margitan", "given_name": "J. J.", "clpid": "Margitan-J-J" }, { "family_name": "Wilson", "given_name": "J. C.", "clpid": "Wilson-J-C" }, { "family_name": "Elkins", "given_name": "J. W.", "clpid": "Elkins-J-W" }, { "family_name": "Stimpfle", "given_name": "R. M.", "clpid": "Stimpfle-R-M" }, { "family_name": "Cohen", "given_name": "R. C.", "orcid": "0000-0001-6617-7691", "clpid": "Cohen-R-C" }, { "family_name": "McElroy", "given_name": "C. T.", "clpid": "McElroy-C-T" }, { "family_name": "Bui", "given_name": "T. P.", "clpid": "Bui-T-P" }, { "family_name": "Salawitch", "given_name": "R. J.", "clpid": "Salawitch-R-J" }, { "family_name": "Brown", "given_name": "S. S.", "clpid": "Brown-S-S" }, { "family_name": "Ravishankara", "given_name": "A. R.", "clpid": "Ravishankara-A-R" }, { "family_name": "Portmann", "given_name": "R. W.", "clpid": "Portmann-R-W" }, { "family_name": "Ko", "given_name": "M. K. W.", "clpid": "Ko-M-K-W" }, { "family_name": "Weisenstein", "given_name": "D. K.", "clpid": "Weisenstein-D-K" }, { "family_name": "Newman", "given_name": "P. A.", "clpid": "Newman-P-A" } ], "abstract": "Extensive airborne measurements of the reactive nitrogen reservoir (NO_(y)) and its component nitric oxide (NO) have been made in the lower stratosphere. Box model simulations that are constrained by observations of radical and long-lived species and which include heterogeneous chemistry systematically underpredict the NO_x (= NO + NO_2) to NO_y ratio. The model agreement is substantially improved if newly measured rate coefficients for the OH + NO_2 and OH + HNO_3 reactions are used. When included in 2-D models, the new rate coefficients significantly increase the calculated ozone loss due to NO_x and modestly change the calculated ozone abundances in the lower stratosphere. Ozone changes associated with the emissions of a fleet of supersonic aircraft are also altered.", "doi": "10.1029/1999GL900162", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "1999-04-15", "series_number": "8", "volume": "26", "issue": "8", "pages": "1153-1156" }, { "id": "authors:h81vm-5vk15", "collection": "authors", "collection_id": "h81vm-5vk15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140716-092820107", "type": "article", "title": "Observed OH and HO_2 in the upper troposphere suggest a major source from convective injection of peroxides", "author": [ { "family_name": "Jaegl\u00e9", "given_name": "L.", "clpid": "Jaegl\u00e9-L" }, { "family_name": "Jacob", "given_name": "D. J.", "orcid": "0000-0002-6373-3100", "clpid": "Jacob-D-J" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Spivakovsky", "given_name": "C. M.", "clpid": "Spivakovsky-C-M" }, { "family_name": "Hanisco", "given_name": "T. F.", "orcid": "0000-0001-9434-8507", "clpid": "Hanisco-T-F" }, { "family_name": "Lanzendorf", "given_name": "E. J.", "clpid": "Lanzendorf-E-J" }, { "family_name": "Hintsa", "given_name": "E. J.", "clpid": "Hintsa-E-J" }, { "family_name": "Fahey", "given_name": "D. W.", "clpid": "Fahey-D-W" }, { "family_name": "Keim", "given_name": "E. R.", "clpid": "Keim-E-R" }, { "family_name": "Proffitt", "given_name": "M. H.", "clpid": "Proffitt-M-H" }, { "family_name": "Atlas", "given_name": "E. L.", "orcid": "0000-0003-3847-5346", "clpid": "Atlas-E-L" }, { "family_name": "Flocke", "given_name": "F.", "clpid": "Flocke-F-M" }, { "family_name": "Schauffler", "given_name": "S.", "clpid": "Schauffler-S" }, { "family_name": "McElroy", "given_name": "C. T.", "clpid": "McElroy-C-T" }, { "family_name": "Midwinter", "given_name": "C.", "clpid": "Midwinter-C" }, { "family_name": "Pfister", "given_name": "L.", "clpid": "Pfister-L" }, { "family_name": "Wilson", "given_name": "J. C.", "clpid": "Wilson-J-C" } ], "abstract": "ER-2 aircraft observations of OH and HO_2 concentrations in the upper troposphere during the NASA/STRAT campaign are interpreted using a photochemical model constrained by local observations of O_3, H_2O, NO, CO, hydrocarbons, albedo and overhead ozone column. We find that the reaction Q(^(1)D) + H_2O is minor compared to acetone photolysis as a primary source of HO_x (= OH + peroxy radicals) in the upper troposphere. Calculations using a diel steady state model agree with observed HO_x concentrations in the lower stratosphere and, for some flights, in the upper troposphere. However, for other flights in the upper troposphere, the steady state model underestimates observations by a factor of 2 or more. These model underestimates are found to be related to a recent (< 1 week) convective origin of the air. By conducting time-dependent model calculations along air trajectories determined for the STRAT flights, we show that convective injection of CH_3OOH and H_2O_2 from the boundary layer to the upper troposphere could resolve the discrepancy. These injections of HO_x reservoirs cause large HO_x increases in the tropical upper troposphere for over a week downwind of the convective activity. We propose that this mechanism provides a major source of HO_x in the upper troposphere. Simultaneous measurements of peroxides, formaldehyde and acetone along with OH and HO_2 are needed to test our hypothesis.", "doi": "10.1029/97GL03004", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "1997-12-15", "series_number": "24", "volume": "24", "issue": "24", "pages": "3181-3184" }, { "id": "authors:51dww-x8v68", "collection": "authors", "collection_id": "51dww-x8v68", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140701-103116252", "type": "article", "title": "Evolution and stoichiometry of heterogeneous processing in the Antarctic stratosphere", "author": [ { "family_name": "Jaegl\u00e9", "given_name": "L.", "clpid": "Jaegl\u00e9-L" }, { "family_name": "Webster", "given_name": "C. R.", "clpid": "Webster-C-R" }, { "family_name": "May", "given_name": "R. D.", "clpid": "May-R-D" }, { "family_name": "Scott", "given_name": "D. C.", "clpid": "Scott-D-C" }, { "family_name": "Stimpfle", "given_name": "R. M.", "clpid": "Stimpfle-R-M" }, { "family_name": "Kohn", "given_name": "D. W.", "clpid": "Kohn-D-W" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Hanisco", "given_name": "T. F.", "orcid": "0000-0001-9434-8507", "clpid": "Hanisco-T-F" }, { "family_name": "Cohen", "given_name": "R. C.", "orcid": "0000-0001-6617-7691", "clpid": "Cohen-R-C" }, { "family_name": "Proffitt", "given_name": "M. H.", "clpid": "Proffitt-M-H" }, { "family_name": "Kelly", "given_name": "K. K.", "clpid": "Kelly-K-K" }, { "family_name": "Elkins", "given_name": "J.", "clpid": "Elkins-J-W" }, { "family_name": "Baumgardner", "given_name": "D.", "clpid": "Baumgardner-D" }, { "family_name": "Dye", "given_name": "J. E.", "clpid": "Dye-J-E" }, { "family_name": "Wilson", "given_name": "J. C.", "clpid": "Wilson-J-C" }, { "family_name": "Pueschel", "given_name": "R. F.", "clpid": "Pueschel-R-F" }, { "family_name": "Chan", "given_name": "K. R.", "clpid": "Chan-K-R" }, { "family_name": "Salawitch", "given_name": "R. J.", "clpid": "Salawitch-R-J" }, { "family_name": "Tuck", "given_name": "A. F.", "clpid": "Tuck-A-F" }, { "family_name": "Hovde", "given_name": "S. J.", "clpid": "Hovde-S-J" }, { "family_name": "Yung", "given_name": "Y. L.", "orcid": "0000-0002-4263-2562", "clpid": "Yung-Y-L" } ], "abstract": "Simultaneous in situ measurements of HCl and ClO have been made for the first time in the southern hemisphere, allowing a systematic study of the processes governing chlorine activation between 15 and 20 km in the 1994 Antarctic winter. Data for several other gases (O_3, NO, NO_y, OH, HO_2, N_(2)O, CH_4, CO, H_(2)O, CFCs), particulates, and meteorological parameters were collected from the ER-2 aircraft out of New Zealand as part of the 1994 Airborne Southern Hemisphere Ozone Experiment/Measurements of Atmospheric Effects of Stratospheric Aircraft (ASHOE/MAESA) campaign. Observations from the ER-2 in the fall (April\u2013May), prior to polar night, show that chlorine activation begins with 60\u201375% of inorganic chlorine as HCl. By midwinter (July\u2013August), near-total removal of HCl is observed. The wintertime loss of HCl in air recently exposed to extreme temperatures is found to be correlated with high levels of reactive chlorine (ClO and its dimer, Cl_(2)O_2) in the linear fashion expected from the stoichiometry of the heterogeneous reaction of hydrochloric acid with chlorine nitrate on polar stratospheric clouds (PSCs): HCl + ClONO_2 \u2192 Cl_2 + HNO_3. To constrain the role of different heterogeneous reactions and PSC types, we have used a photochemical trajectory model which includes heterogeneous sulfate and PSC chemistry. Model calculations of the evolution of reactive gases are compared with the in situ observations. In addition, simultaneous measurements of OH and HO_2 are used as a diagnostic for the occurrence of the heterogeneous reaction HOCl + HCl \u2192 Cl_2 + H_(2)O, which contributes to suppressed levels of HO_x inside the vortex. It is shown that the amount of chlorine activation is not strongly dependent on the composition of PSCs. However, HO_x levels exhibit different signatures depending on the type of heterogeneous surfaces that affected chlorine activation. Furthermore, this analysis implies that in the edge region of the Antarctic vortex, the observed near-total removal of HCl can result from latitudinal excursions of air parcels in and out of sunlight during the winter, which photochemically resupply HOCl and ClONO_2 as oxidation partners for HCl.", "doi": "10.1029/97JD00935", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "1997-06-20", "series_number": "D11", "volume": "102", "issue": "D11", "pages": "13235-13253" }, { "id": "authors:0xkav-k7786", "collection": "authors", "collection_id": "0xkav-k7786", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140718-115240464", "type": "article", "title": "Observations of large reductions in the NO/NO_y ratio near the mid-latitude tropopause and the role of heterogeneous chemistry", "author": [ { "family_name": "Keim", "given_name": "E. R.", "clpid": "Keim-E-R" }, { "family_name": "Fahey", "given_name": "D. W.", "clpid": "Fahey-D-W" }, { "family_name": "Del Negro", "given_name": "L. A.", "clpid": "Del-Negro-L-A" }, { "family_name": "Woodbridge", "given_name": "E. L.", "clpid": "Woodbridge-E-L" }, { "family_name": "Gao", "given_name": "R. S.", "clpid": "Gao-R-S" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Cohen", "given_name": "R. C.", "orcid": "0000-0001-6617-7691", "clpid": "Cohen-R-C" }, { "family_name": "Stimpfle", "given_name": "R. M.", "clpid": "Stimpfle-R-M" }, { "family_name": "Kelly", "given_name": "K. K.", "clpid": "Kelly-K-K" }, { "family_name": "Hintsa", "given_name": "E. J.", "clpid": "Hintsa-E-J" }, { "family_name": "Wilson", "given_name": "J. C.", "clpid": "Wilson-J-C" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Dye", "given_name": "J. E.", "clpid": "Dye-J-E" }, { "family_name": "Baumgardner", "given_name": "D.", "clpid": "Baumgardner-D" }, { "family_name": "Kawa", "given_name": "S. R.", "clpid": "Kawa-S-R" }, { "family_name": "Salawitch", "given_name": "R. J.", "clpid": "Salawitch-R-J" }, { "family_name": "Proffitt", "given_name": "M. H.", "clpid": "Proffitt-M-H" }, { "family_name": "Loewenstein", "given_name": "M.", "clpid": "Loewenstein-M" }, { "family_name": "Podolske", "given_name": "J. R.", "clpid": "Podolske-J-R" }, { "family_name": "Chan", "given_name": "K. R.", "clpid": "Chan-K-R" } ], "abstract": "During the 1993 NASA Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE), anomalously low nitric oxide (NO) was found in a distinct sunlit layer located above the mid-latitude tropopause. The presence of a significant amount of reactive nitrogen (NO_y) in the layer implies the systematic removal of NO, which is without precedent in stratospheric in situ observations. Large increases in measured chlorine monoxide (ClO) and the hydroperoxyl radical (HO_2) also were observed in the layer. Heterogeneous reaction rate constants of chlorine nitrate (ClONO_2) with hydrogen chloride (HCl) and H_2O to form nitric acid (HNO_3) on sulfate aerosol are enhanced in the NO removal layer by local increases in H_2O and aerosol surface area. The associated conversion of NO_x (= NO + NO_2) to HNO_3 is the most likely cause of the observed low NO and NO_x/NO_y values and high ClO values.", "doi": "10.1029/96GL02593", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "1996-11-01", "series_number": "22", "volume": "23", "issue": "22", "pages": "3223-3226" }, { "id": "authors:kmgbb-ppp91", "collection": "authors", "collection_id": "kmgbb-ppp91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140702-094446231", "type": "article", "title": "The diurnal variation of hydrogen, nitrogen, and chlorine\n radicals: implications for the heterogeneous production of\n HNO\u2082", "author": [ { "family_name": "Salawitch", "given_name": "R. J.", "orcid": "0000-0001-8597-5832", "clpid": "Salawitch-Ross-J" }, { "family_name": "Wofsy", "given_name": "S. C.", "orcid": "0000-0002-3133-2089", "clpid": "Wofsy-Steven-C" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Cohen", "given_name": "R. C.", "orcid": "0000-0001-6617-7691", "clpid": "Cohen-Ronald-C" }, { "family_name": "Anderson", "given_name": "J. G.", "clpid": "Anderson-J-G" }, { "family_name": "Fahey", "given_name": "D. W.", "orcid": "0000-0003-1720-0634", "clpid": "Fahey-David-W" }, { "family_name": "Gao", "given_name": "R. S.", "clpid": "Gao-R-S" }, { "family_name": "Keim", "given_name": "E. R.", "clpid": "Keim-E-R" }, { "family_name": "Woodbridge", "given_name": "E. L.", "clpid": "Woodbridge-E-L" }, { "family_name": "Stimpfle", "given_name": "R. M.", "clpid": "Stimpfle-R-M" }, { "family_name": "Koplow", "given_name": "J. P.", "clpid": "Koplow-J-P" }, { "family_name": "Kohn", "given_name": "D. W.", "clpid": "Kohn-D-W" }, { "family_name": "Webster", "given_name": "C. R.", "clpid": "Webster-C-R" }, { "family_name": "May", "given_name": "R. D.", "clpid": "May-R-D" }, { "family_name": "Pfister", "given_name": "L.", "clpid": "Pfister-L" }, { "family_name": "Gottlieb", "given_name": "E. W.", "clpid": "Gottlieb-Elaine-W" }, { "family_name": "Michelsen", "given_name": "H. A.", "orcid": "0000-0001-5802-6615", "clpid": "Michelsen-Hope-A" }, { "family_name": "Yue", "given_name": "G. K.", "clpid": "Yue-G-K" }, { "family_name": "Prather", "given_name": "M. J.", "orcid": "0000-0002-9442-8109", "clpid": "Prather-Michael-J" }, { "family_name": "Wilson", "given_name": "J. C.", "clpid": "Wilson-J-C" }, { "family_name": "Brock", "given_name": "C. A.", "orcid": "0000-0002-4033-4668", "clpid": "Brock-Charles-A" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Dye", "given_name": "J. E.", "clpid": "Dye-J-E" }, { "family_name": "Baumgardner", "given_name": "D.", "clpid": "Baumgardner-Darrel" }, { "family_name": "Proffitt", "given_name": "M", "clpid": "Proffitt-M" }, { "family_name": "Loewenstein", "given_name": "M.", "clpid": "Loewenstein-M" }, { "family_name": "Podolske", "given_name": "J. R.", "orcid": "0000-0003-2771-5375", "clpid": "Podolske-James-R" }, { "family_name": "Elkins", "given_name": "J. W.", "orcid": "0000-0003-4701-3100", "clpid": "Elkins-James-W" }, { "family_name": "Dutton", "given_name": "G. S.", "orcid": "0000-0001-7777-9268", "clpid": "Dutton-Geoffrey-S" }, { "family_name": "Hintsa", "given_name": "E. J.", "orcid": "0000-0002-5289-630X", "clpid": "Hintsa-Eric-J" }, { "family_name": "Dessler", "given_name": "A. E.", "clpid": "Dessler-A-E" }, { "family_name": "Weinstock", "given_name": "E. M.", "clpid": "Weinstock-E-M" }, { "family_name": "Kelly", "given_name": "K. K.", "clpid": "Kelly-K-K" }, { "family_name": "Boering", "given_name": "K. A.", "orcid": "0000-0003-0920-0503", "clpid": "Boering-Kristie-A" }, { "family_name": "Daube", "given_name": "B. C.", "clpid": "Daube-Bruce-C-Jr" }, { "family_name": "Chan", "given_name": "K. R.", "clpid": "Chan-K-R" }, { "family_name": "Bowen", "given_name": "S. W.", "clpid": "Bowen-S-W" } ], "abstract": "In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained through sunrise and sunset in the lower stratosphere during SPADE are compared to results from a photochemical model constrained by observed concentrations of radical precursors and environmental conditions. Models allowing for heterogeneous hydrolysis of N\u2082O\u2085 on sulfate aerosols agree with measured concentrations of NO, NO\u2082, and ClO throughout the day, but fail to account for high concentrations of OH and HO\u2082 observed near sunrise and sunset. The morning burst of [OH] and [HO\u2082] coincides with the rise of [NO] from photolysis of NO\u2082, suggesting a new source of HO\u2093 that photolyzes in the near UV (350 to 400 nm) spectral region. A model that allows for the heterogeneous production of HNO\u2082 results in an excellent simulation of the diurnal variations of [OH] and [HO\u2082].", "doi": "10.1029/94GL02782", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "1994-11-15", "series_number": "23", "volume": "21", "issue": "23", "pages": "2551-2554" }, { "id": "authors:40bq2-pqe93", "collection": "authors", "collection_id": "40bq2-pqe93", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140716-091039510", "type": "article", "title": "The distribution of hydrogen, nitrogen, and chlorine radicals in the lower stratosphere: Implications for changes in O_3 due to emission of NO_y from supersonic aircraft", "author": [ { "family_name": "Salawitch", "given_name": "R. J.", "clpid": "Salawitch-R-J" }, { "family_name": "Wofsy", "given_name": "S. C.", "orcid": "0000-0002-3990-6737", "clpid": "Wofsy-S-C" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Cohen", "given_name": "R. C.", "orcid": "0000-0001-6617-7691", "clpid": "Cohen-R-C" }, { "family_name": "Anderson", "given_name": "J. G.", "clpid": "Anderson-J-G" }, { "family_name": "Fahey", "given_name": "D. W.", "clpid": "Fahey-D-W" }, { "family_name": "Gao", "given_name": "R. S.", "clpid": "Gao-R-S" }, { "family_name": "Keim", "given_name": "E. R.", "clpid": "Keim-E-R" }, { "family_name": "Woodbridge", "given_name": "E. L.", "clpid": "Woodbridge-E-L" }, { "family_name": "Stimpfle", "given_name": "R. M.", "clpid": "Stimpfle-R-M" }, { "family_name": "Koplow", "given_name": "J. P.", "clpid": "Koplow-J-P" }, { "family_name": "Kohn", "given_name": "D. W.", "clpid": "Kohn-D-W" }, { "family_name": "Webster", "given_name": "C. R.", "clpid": "Webster-C-R" }, { "family_name": "May", "given_name": "R. D.", "clpid": "May-R-D" }, { "family_name": "Pfister", "given_name": "L.", "clpid": "Pfister-L" }, { "family_name": "Gottlieb", "given_name": "E. W.", "clpid": "Gottlieb-E-W" }, { "family_name": "Michelsen", "given_name": "H. A.", "clpid": "Michelsen-H-A" }, { "family_name": "Yue", "given_name": "G. K.", "clpid": "Yue-G-K" }, { "family_name": "Wilson", "given_name": "J. C.", "clpid": "Wilson-J-C" }, { "family_name": "Brock", "given_name": "C. A.", "clpid": "Brock-C-A" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Dye", "given_name": "J. E.", "clpid": "Dye-J-E" }, { "family_name": "Baumgardner", "given_name": "D.", "clpid": "Baumgardner-D" }, { "family_name": "Proffitt", "given_name": "M. H.", "clpid": "Proffitt-M-H" }, { "family_name": "Loewenstein", "given_name": "M.", "clpid": "Loewenstein-M" }, { "family_name": "Podolske", "given_name": "J. R.", "clpid": "Podolske-J-R" }, { "family_name": "Elkins", "given_name": "J. W.", "clpid": "Elkins-J-W" }, { "family_name": "Dutton", "given_name": "G. S.", "clpid": "Dutton-G-S" }, { "family_name": "Hintsa", "given_name": "E. J.", "clpid": "Hintsa-E-J" }, { "family_name": "Dessler", "given_name": "A. E.", "clpid": "Dessler-A-E" }, { "family_name": "Weinstock", "given_name": "E. M.", "clpid": "Weinstock-E-M" }, { "family_name": "Kelly", "given_name": "K. K.", "clpid": "Kelly-K-K" }, { "family_name": "Boering", "given_name": "K. A.", "clpid": "Boering-K-A" }, { "family_name": "Daube", "given_name": "B. C.", "clpid": "Daube-B-C-Jr" }, { "family_name": "Chan", "given_name": "K. R.", "clpid": "Chan-K-R" }, { "family_name": "Bowen", "given_name": "S. W.", "clpid": "Bowen-S-W" } ], "abstract": "In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained in the lower stratosphere during SPADE are compared to results from a photochemical model that assimilates measurements of radical precursors and environmental conditions. Models allowing for heterogeneous hydrolysis of N_2O_5 agree well with measured concentrations of NO and ClO, but concentrations of HO_2 and OH are underestimated by 10 to 25%, concentrations of NO_2 are overestimated by 10 to 30%, and concentrations of HCl are overestimated by a factor of 2. Discrepancies for [OH] and [HO_2] are reduced if we allow for higher yields of O(^1D) from O_3 photolysis and for heterogeneous production of HNO_2. The data suggest more efficient catalytic removal of O_3 by hydrogen and halogen radicals relative to nitrogen oxide radicals than predicted by models using recommended rates and cross sections. Increases in [O_3] in the lower stratosphere may be larger in response to inputs of NO_y from supersonic aircraft than estimated by current assessment models.", "doi": "10.1029/94GL02781", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "1994-11-15", "series_number": "23", "volume": "21", "issue": "23", "pages": "2547-2550" }, { "id": "authors:8bkhc-faa92", "collection": "authors", "collection_id": "8bkhc-faa92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140903-112427480", "type": "article", "title": "Spatial variation of ground motion determined from accelerograms recorded on a highway bridge", "author": [ { "family_name": "Wilson", "given_name": "John C.", "clpid": "Wilson-J-C" }, { "family_name": "Jennings", "given_name": "Paul C.", "clpid": "Jennings-P-C" } ], "abstract": "A set of time-synchronized strong-motion accelerograms, obtained on the San Juan Bautista 156/101 Separation Bridge in California during the 6 August 1979 Coyote Lake earthquake (M_L = 5.9), are used to study the spatial variation of ground motion at the bridge site, including traveling wave effects and the influence of multiple-support excitation. Analysis of the ground motion recorded at the base of two of the bridge supports (32.6 m apart) revealed the presence of a differential support excitation having a period of \u2248 3 sec, much longer than any structural periods of the bridge. This signal also appeared as a noticeable long-period component in the superstructure displacements. Analysis of the vertical and radial components of the 3-sec ground motion indicated that ground displacements were retrograde for the duration of strong shaking, with several cycles exhibiting elliptical particle motions. These findings suggest that long-period differential support motions were induced by phase delays in a Rayleigh wave traveling across the bridge site. Further support to this premise is given by the location of the bridge site near a maxima of the Rayleigh wave radiation pattern for the Coyote Lake earthquake (based on published focal mechanism data). Traveling wave effects were also detected for compressional body waves by a correlation analysis which indicated a time delay of \u2248 7 msec between P-wave arrivals at two of the bridge supports.", "issn": "0037-1106", "publisher": "Seismological Society of America", "publication": "Bulletin of the Seismological Society of America", "publication_date": "1985-12", "series_number": "6", "volume": "75", "issue": "6", "pages": "1515-1533" } ]