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  • Journal article
    Pisa D, Hospodarsky GB, Kurth WS, Santolik O, Soucek J, Gurnett DA, Masters A, Hill MEet al., 2015,

    , JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 120, Pages: 2531-2542, ISSN: 2169-9380
  • Journal article
    Yates JN, Southwood DJ, Dougherty MK, 2015,

    , JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 120, Pages: 2631-2648, ISSN: 2169-9380
  • Journal article
    Delamere PA, Bagenal F, Paranicas C, Masters A, Radioti A, Bonfond B, Ray L, Jia X, Nichols J, Arridge Cet al., 2015,

    , SPACE SCIENCE REVIEWS, Vol: 187, Pages: 51-97, ISSN: 0038-6308
    • Cite
    • Citations: 51
  • Journal article
    Fox C, Green PD, Pickering JC, Humpage Net al., 2015,

    , JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, Vol: 155, Pages: 57-65, ISSN: 0022-4073
  • Journal article
    Kimura T, Badman SV, Tao C, Yoshioka K, Murakami G, Yamazaki A, Tsuchiya F, Bonfond B, Steffl AJ, Masters A, Kasahara S, Hasegawa H, Yoshikawa I, Fujimoto M, Clarke JTet al., 2015,

    , GEOPHYSICAL RESEARCH LETTERS, Vol: 42, Pages: 1662-1668, ISSN: 0094-8276
    • Cite
    • Citations: 57
  • Journal article
    Cui J, Galand M, Yelle RV, Wei Y, Zhang S-Jet al., 2015,

    , Journal of Geophysical 91桃色: Space Physics, Vol: 120, Pages: 2333-2346, ISSN: 2169-9402

    The nightside Martian ionosphere is thought to be contributed by day-to-night transport and electron precipitation, of which the former has not been well studied. In this work, we evaluate the role of day-to-night transport based on the total electron content (TEC) measurements made by the Mars Advanced Radar for Subsurface and Ionospheric Sounding on board Mars Express. This is accomplished by an examination of the variation of nightside TEC in the time domain rather than the traditional solar zenith angle domain. Our analyses here, being constrained to the Northern Hemisphere where the effects of crustal magnetic fields can be neglected, reveal that day-to-night transport serves as the dominant source for the nightside Martian ionosphere from terminator crossing up to time in darkness of ≈5.3 × 103 s, beyond which it is surpassed by electron precipitation. The observations are compared with predictions from a simplified time-dependent ionosphere model. We conclude that the solid body rotation of Mars is insufficient to account for the observed depletion of nightside TEC but the data could be reasonably reproduced by a zonal electron flow velocity of ≈1.9 km s−1.
  • Journal article
    Matteini L, Horbury TS, Pantellini F, Velli M, Schwartz SJet al., 2015,

    , Astrophysical Journal, Vol: 802, ISSN: 1538-4357

    We investigate the properties of plasma fluid motion in the large-amplitude, low-frequency fluctuations of highlyAlfvénic fast solar wind. We show that protons locally conserve total kinetic energy when observed from aneffective frame of reference comoving with the fluctuations. For typical properties of the fast wind, this frame canbe reasonably identified by alpha particles which, due to their drift with respect to protons at about the Alfvénspeed along the magnetic field, do not partake in the fluid low-frequency fluctuations. Using their velocity totransform the proton velocity into the frame of Alfvénic turbulence, we demonstrate that the resulting plasmamotion is characterized by a constant absolute value of the velocity, zero electric fields, and aligned velocity andmagnetic field vectors as expected for unidirectional Alfvénic fluctuations in equilibrium. We propose that thisconstraint, via the correlation between velocity and magnetic field in Alfvénic turbulence, is the origin of theobserved constancy of the magnetic field; while the constant velocity corresponding to constant energy can only beobserved in the frame of the fluctuations, the corresponding constant total magnetic field, invariant for Galileantransformations, remains the observational signature in the spacecraft frame of the constant total energy in theAlfvén turbulence frame
  • Journal article
    Gingell PW, Burgess D, Matteini L, 2015,

    , ASTROPHYSICAL JOURNAL, Vol: 802, ISSN: 0004-637X
    • Cite
    • Citations: 20
  • Journal article
    Martinez-Oliveros JC, Raftery C, Bain H, Liu Y, Pulupa M, Saint-Hilaire P, Higgins P, Krupar V, Krucker S, Bale SDet al., 2015,

    , SOLAR PHYSICS, Vol: 290, Pages: 891-901, ISSN: 0038-0938
  • Journal article
    Nazarenko L, Schmidt GA, Miller RL, Tausnev N, Kelley M, Ruedy R, Russell GL, Aleinov I, Bauer M, Bauer S, Bleck R, Canuto V, Cheng Y, Clune TL, Del Genio AD, Faluvegi G, Hansen JE, Healy RJ, Kiang NY, Koch D, Lacis AA, LeGrande AN, Lerner J, Lo KK, Menon S, Oinas V, Perlwitz J, Puma MJ, Rind D, Romanou A, Sato M, Shindell DT, Sun S, Tsigaridis K, Unger N, Voulgarakis A, Yao M-S, Zhang Jet al., 2015,

    , JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS, Vol: 7, Pages: 244-267
    • Cite
    • Citations: 117
  • Journal article
    Cui J, Galand M, Zhang SJ, Vigren E, Zou Het al., 2015,

    , Journal of Geophysical 91桃色: Planets, Vol: 120, Pages: 278-286, ISSN: 2169-9100

    We propose a revised Chapman model for the ionosphere of Mars by allowing for vertical variation of electron temperature. An approximate energy balance between solar EUV heating and CO2 collisional cooling is applied in the dayside Martian ionosphere, analogous to the method recently proposed by Withers et al. (2014). The essence of the model is to separate the contributions of the neutral and electron thermal structures to the apparent width of the main ionospheric layer. Application of the model to the electron density profiles from the Mars Global Surveyor (MGS) radio occultation measurements reveals a clear trend of elevated electron temperature with increasing solar zenith angle (SZA). It also reveals that the characteristic length scale for the change of electron temperature with altitude decreases with increasing SZA. These observations may imply enhanced topside heat influx near the terminator, presumably an outcome of the solar wind interactions with the Martian upper atmosphere. Our analysis also reveals a tentative asymmetry in electron temperature between the northern and southern hemispheres, consistent with the scenario of elevated electron temperature within minimagnetospheres.
  • Conference paper
    Pickering JC, Fox C, Murray JE, Last Aet al., 2015,

    The cirrus coupled cloud-radiation experiment: CIRCCREX

    We report early results from the Cirrus Coupled Cloud-Radiation Experiment CIRCCREX investigating cirrus through airborne campaigns including radiation measurements (0.3-125μm). Cirrus models and parameterizations used in radiative transfer codes and numerical weather prediction will be tested.
  • Journal article
    Goldberg SJ, Ball GI, Allen BC, Schladow SG, Simpson AJ, Masoom H, Soong R, Graven HD, Aluwihare LIet al., 2015,

    , Nature Communications, Vol: 6, ISSN: 2041-1723

    The role of dissolved organic matter (DOM) as either a sink for inorganic nutrients or anadditional nutrient source is an often-neglected component of nutrient budgets in aquaticenvironments. Here, we examined the role of DOM in reactive nitrogen (N) storage in SierraNevada (California, USA) lakes where atmospheric deposition of N has shifted the lakestoward seasonal phosphorus (P)-limitation. Nuclear magnetic resonance (NMR) spectroscopyand isotope analyses performed on DOM isolated from Lake Tahoe reveal the accumulationof refractory proteinaceous material with a 100–200-year residence time. Incontrast, smaller lakes in the same watershed contain DOM with typical terrestrial characteristics,indicating that proteins in Lake Tahoe are autochthonously produced. These datasupport the role of DOM as a possible sink for reactive N in these lake ecosystems andidentify a potential role for DOM in affecting the inorganic nutrient stoichiometry of theseenvironments.
  • Conference paper
    Pickering JC, Fox C, Murray JE, Last Aet al., 2015,

    We report early results from the Cirrus Coupled Cloud-Radiation Experiment CIRCCREX investigating cirrus through airborne campaigns including radiation measurements (0.3-125μm). Cirrus models and parameterizations used in radiative transfer codes and numerical weather prediction will be tested.
  • Conference paper
    Pickering JC, Mushtaq S, Steers EBM, Weiss Zet al., 2015,

    High resolution FTS studies of the effects of trace molecular gases on Glow Discharge spectra and industrial applications

    Analytical Glow Discharge (GD) Optical Emission Spectroscopy and GD Mass Spectrometry have important industrial applications. The analytical accuracy may be affected by trace molecular gases. High resolution FTS is used to investigate fundamental discharge processes.
  • Conference paper
    Pickering JC, Mushtaq S, Steers EBM, Weiss Zet al., 2015,

    Analytical Glow Discharge (GD) Optical Emission Spectroscopy and GD Mass Spectrometry have important industrial applications. The analytical accuracy may be affected by trace molecular gases. High resolution FTS is used to investigate fundamental discharge processes.
  • Book chapter
    Southwood DJ, 2015,

    Formation of Magnetotails: Fast and Slow Rotators Compared

    , Magnetotails in the Solar System, Editors: Keiling, Jackman, Publisher: John Wiley & Sons, Pages: 199-215, ISBN: 9781118842348
  • Journal article
    Brindley H, Bantges R, Russell J, Murray J, Dancel C, Belotti C, Harries Jet al., 2015,

    , JOURNAL OF CLIMATE, Vol: 28, Pages: 1649-1660, ISSN: 0894-8755
    • Cite
    • Citations: 15
  • Journal article
    Eastwood JP, Goldman MV, Hietala H, Newman DL, Mistry R, Lapenta Get al., 2015,

    , Journal of Geophysical 91桃色: Space Physics, Vol: 120, Pages: 511-525, ISSN: 2169-9402

    Dipolarization fronts (DFs) are often associated with the leading edge of earthward bursty bulk flows in the magnetotail plasma sheet. Here multispacecraft Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations are used to show that a spatially limited region of counterpropagating ion beams, whose existence is not evident in either the plasma moments or the electric field, is observed on the low-density side of DFs. The THEMIS magnetic field data are used to establish appropriate comparison cuts through a particle-in-cell simulation of reconnection, and very good agreement is found between the observed and simulated ion distributions on both sides of the DF. Self-consistent back tracing shows that the ion beams originate from the thermal component of the preexisting high-density plasma into which the DF is propagating; they do not originate from the inflow region in the traditional sense. Forward tracing shows that some of these ions can subsequently overtake the DF and pass back into the high-density preexisting plasma sheet with an order-of-magnitude increase in energy; this process is distinct from other ion reflection processes that occur directly at the DF. The interaction of the reconnection jet with the preexisting plasma sheet therefore occurs over a macroscopic region, rather than simply being limited to the thin DF interface. A more general consequence of this study is the conclusion that reconnection jets are not simply fed by plasma inflow across the separatrices but are also fed by plasma from the region into which the jet is propagating; the implications of this finding are discussed.
  • Journal article
    Bertucci C, Hamilton DC, Kurth WS, Hospodarsky G, Mitchell D, Sergis N, Edberg NJT, Dougherty MKet al., 2015,

    , GEOPHYSICAL RESEARCH LETTERS, Vol: 42, Pages: 193-200, ISSN: 0094-8276
    • Cite
    • Citations: 42
  • Journal article
    Nilsson H, Wieser GS, Behar E, Wedlund CS, Gunell H, Yamauchi M, Lundin R, Barabash S, Wieser M, Carr C, Cupido E, Burch JL, Fedorov A, Sauvaud J-A, Koskinen H, Kallio E, Lebreton J-P, Eriksson A, Edberg N, Goldstein R, Henri P, Koenders C, Mokashi P, Nemeth Z, Richter I, Szego K, Volwerk M, Vallat C, Rubin Met al., 2015,

    , Science, Vol: 347, ISSN: 0036-8075

    The Rosetta mission shall accompany comet 67P/Churyumov-Gerasimenko from a heliocentric distance of >3.6 astronomical units through perihelion passage at 1.25 astronomical units, spanning low and maximum activity levels. Initially, the solar wind permeates the thin comet atmosphere formed from sublimation, until the size and plasma pressure of the ionized atmosphere define its boundaries: A magnetosphere is born. Using the Rosetta Plasma Consortium ion composition analyzer, we trace the evolution from the first detection of water ions to when the atmosphere begins repelling the solar wind (~3.3 astronomical units), and we report the spatial structure of this early interaction. The near-comet water population comprises accelerated ions (<800 electron volts), produced upstream of Rosetta, and lower energy locally produced ions; we estimate the fluxes of both ion species and energetic neutral atoms.
  • Journal article
    Hassig M, Altwegg K, Balsiger H, Bar-Nun A, Berthelier JJ, Bieler A, Bochsler P, Briois C, Calmonte U, Combi M, De Keyser J, Eberhardt P, Fiethe B, Fuselier SA, Galand M, Gasc S, Gombosi TI, Hansen KC, Jackel A, Keller HU, Kopp E, Korth A, Kuehrt E, Le Roy L, Mall U, Marty B, Mousis O, Neefs E, Owen T, Reme H, Rubin M, Semon T, Tornow C, Tzou C-Y, Waite JH, Wurz Pet al., 2015,

    , Science, Vol: 347, ISSN: 0036-8075

    Comets contain the best-preserved material from the beginning of our planetary system. Their nuclei and comae composition reveal clues about physical and chemical conditions during the early solar system when comets formed. ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) onboard the Rosetta spacecraft has measured the coma composition of comet 67P/Churyumov-Gerasimenko with well-sampled time resolution per rotation. Measurements were made over many comet rotation periods and a wide range of latitudes. These measurements show large fluctuations in composition in a heterogeneous coma that has diurnal and possibly seasonal variations in the major outgassing species: water, carbon monoxide, and carbon dioxide. These results indicate a complex coma-nucleus relationship where seasonal variations may be driven by temperature differences just below the comet surface.
  • Journal article
    Vigren E, Galand M, Lavvas P, Eriksson AI, Wahlund J-Eet al., 2015,

    , Astrophysical Journal, Vol: 798, ISSN: 1538-4357
  • Book chapter
    Eastwood JP, Kiehas SA, 2015,

    , Magnetotails in the Solar System, Pages: 269-287

    This chapter discusses the origin and evolution of plasmoids and flux ropes in Earth's magnetotail, providing an overview of author's current understanding based on recent multipoint and multimission data analysis. It also presents recent results concerning observations of flux ropes in the vicinity of Mars. Understanding the Mars solar wind interaction is very important for determining its atmospheric history, and recent discoveries show that magnetic reconnection-generated structures may play a significant role, particularly in the vicinity of the crustal field regions. The chapter briefly discusses some of the different terms used to describe reconnection-generated structures. It describes the production of islands, plasmoids, and secondary islands by antiparallel reconnection.
  • Journal article
    O'Reilly CH, Czaja A, 2015,

    , Quarterly Journal of the Royal Meteorological Society, Vol: 141, Pages: 52-66, ISSN: 0035-9009

    An index of the Kuroshio Extension front strength is produced using a maximum covariance analysis between sea鈥恠urface temperature (SST) and sea鈥恠urface height (SSH) gradient observations, and composites of the atmospheric state are presented during its positive and negative phases using reanalysis data (1992–2011).It is found that when the Kuroshio Extension is less (more) meandering, with a stronger (weaker) SST front, the atmospheric heat transport by transient eddies is increased in the western (eastern) Pacific region, consistent with an increase (decrease) in low鈥恖evel baroclinicity. Analysis of the eddy–mean flow interaction shows that this zonal shift in heat transport forces anomalous barotropic flow in the Eastern Pacific, where blocking frequency is strongly influenced.The above relationships cannot be reconciled with the known response of the North Pacific storm track to remote forcing from the Tropical Pacific, nor can they be explained by the response of the ocean to atmospheric forcing via surface heat fluxes or winds. Rather, the zonal shift in the storm track highlighted here, and the associated changes in the large鈥恠cale circulation, are interpreted as a response to the interannual variability of the Kuroshio Extension front.
  • Journal article
    Klueser L, Banks JR, Martynenko D, Bergemann C, Brindley HE, Holzer-Popp Tet al., 2015,

    , REMOTE SENSING OF ENVIRONMENT, Vol: 156, Pages: 294-309, ISSN: 0034-4257
    • Cite
    • Citations: 20
  • Journal article
    Eastwood JP, Kataria DO, McInnes CR, Barnes NC, Mulligan Pet al., 2015,

    , WEATHER, Vol: 70, Pages: 27-30, ISSN: 0043-1656
    • Cite
    • Citations: 13
  • Journal article
    Del Zanna L, Matteini L, Landi S, Verdini A, Velli Met al., 2015,

    , Journal of Plasma Physics, Vol: 81, ISSN: 0022-3778

    <jats:p>The long-term evolution of large-amplitude Alfvén waves propagating in the solar wind is investigated by performing two-dimensional MHD simulations within the expanding box model. The linear and nonlinear phases of the parametric decay instability are studied for both circularly polarized waves in parallel propagation and for arc-polarized waves in oblique propagation. The non-monochromatic case is also considered. In the oblique case, the direct excitation of daughter modes transverse to the local background field is found for the first time in an expanding environment, and this transverse cascade seems to be favored for monochromatic mother waves. The expansion effect reduces the instability growth rate, and it can even suppress its onset for the lowest frequency modes considered here, possibly explaining the persistence of these outgoing waves in the solar wind.</jats:p>
  • Journal article
    Sparks N, Toumi R, 2015,

    , BOUNDARY-LAYER METEOROLOGY, Vol: 154, Pages: 101-117, ISSN: 0006-8314
  • Journal article
    Masters A, 2015,

    , JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 120, Pages: 479-493, ISSN: 2169-9380
    • Cite
    • Citations: 26

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