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  • Conference paper
    Murray J, Fox S, O'Shea S, Thornton J, Trembath J, Fugal J, Pickering J, Fox C, Brooke J, Harlow C, Bower K, Ulanowski J, Baran A, Brindley H, Ritter G, Last Aet al., 2016,

    The cirrus coupled cloud-radiation experiment-II

    A cirrus study has been undertaken during the second Cirrus Cloud-Radiation Experiment field campaign based in Prestwick, Scotland. We report on a case study describing the radiation and microphysics measurements and cloud modelling work.
  • Conference paper
    Brindley H, Murray J, Bellisario C, Harlow C, Woolley A, Fox S, Last A, Pickering Jet al., 2016,

    Estimating far infrared surface emissivity over greenland from the tropospheric airborne fourier transform spectrometer (TAFTS)

    We report on efforts to obtain observationally based estimates of far-infrared surface emissivity over snow and ice. We highlight one flight from the CIRCCREX-COSMICS airborne campaign over Greenland during March 2015.
  • Journal article
    Roussos E, Krupp N, Mitchell DG, Paranicas C, Krimigis SM, Andriopoulou M, Palmaerts B, Kurth WS, Badman SV, Masters A, Dougherty MKet al., 2016,

    Quasi-periodic injections of relativistic electrons in Saturn’s outer magnetosphere

    , Icarus, Vol: 263, Pages: 101-116, ISSN: 1090-2643

    Quasi-periodic, short-period injections of relativistic electrons have been observed in both Jupiter’s and Saturn’s magnetospheres, but understanding their origin or significance has been challenging, primarily due to the limited number of in-situ observations of such events by past flyby missions. Here we present the first survey of such injections in an outer planetary magnetosphere using almost nine years of energetic charged particle and magnetic field measurements at Saturn. We focus on events with a characteristic period of about 60–70 min (QP60, where QP stands for quasi-periodic). We find that the majority of QP60, which are very common in the outer magnetosphere, map outside Titan’s orbit. QP60 are also observed over a very wide range of local times and latitudes. A local time asymmetry in their distribution is the most striking feature, with QP60 at dusk being between 5 and 25 times more frequent than at dawn. Field-line tracing and pitch angle distributions suggest that most events at dusk reside on closed field lines. They are distributed either near the magnetopause, or, in the case of the post-dusk (or pre-midnight) sector, up to about 30 RS inside it, along an area extending parallel to the dawn–dusk direction. QP60 at dawn map either on open field lines and/or near the magnetopause. Both the asymmetries and varying mapping characteristics as a function of local time indicate that generation of QP60 cannot be assigned to a single process. The locations of QP60 seem to trace sites that reconnection is expected to take place. In that respect, the subset of events observed post-dusk and deep inside the magnetopause may be directly or indirectly linked to the Vasyliunas reconnection cycle, while magnetopause reconnection/Kelvin–Helmholtz (KH) instability could be invoked to explain all other events at the duskside. Using similar arguments, injections at the dawnside magnetosphere may result from solar-wind induced storm
  • Book chapter
    Haigh JD, 2016,

    Blue Sky; Mirages, haloes and sundogs; Rainbows; Space Weather; Sunshine; Sunspots and Climate

    , 30-Second Meteorology: The 50 Most Significant Events and Phenomena, Each Explained in Half a Minute, Editors: Scaife, ISBN: 978-1-7824-0310-4
  • Journal article
    Ceppi P, Hartmann DL, Webb MJ, 2016,

    Mechanisms of the negative shortwave cloud feedback in middle to high latitudes

    , Journal of Climate, Vol: 29, Pages: 139-157, ISSN: 0894-8755

    Increases in cloud optical depth and liquid water path (LWP) are robust features of global warming model simulations in high latitudes, yielding a negative shortwave cloud feedback, but the mechanisms are still uncertain. Here the importance of microphysical processes for the negative optical depth feedback is assessed by perturbing temperature in the microphysics schemes of two aquaplanet models, both of which have separate prognostic equations for liquid water and ice. It is found that most of the LWP increase with warming is caused by a suppression of ice microphysical processes in mixed-phase clouds, resulting in reduced conversion efficiencies of liquid water to ice and precipitation. Perturbing the temperature-dependent phase partitioning of convective condensate also yields a small LWP increase. Together, the perturbations in large-scale microphysics and convective condensate partitioning explain more than two-thirds of the LWP response relative to a reference case with increased SSTs, and capture all of the vertical structure of the liquid water response. In support of these findings, a very robust positive relationship between monthly mean LWP and temperature in CMIP5 models and observations is shown to exist in mixed-phase cloud regions only. In models, the historical LWP sensitivity to temperature is a good predictor of the forced global warming response poleward of about 45°, although models appear to overestimate the LWP response to warming compared to observations. The results indicate that in climate models, the suppression of ice-phase microphysical processes that deplete cloud liquid water is a key driver of the LWP increase with warming and of the associated negative shortwave cloud feedback.
  • Journal article
    Rabin SS, Melton JR, Lasslop G, Bachelet D, Forrest M, Hantson S, Li F, Mangeon S, Yue C, Arora VK, Hickler T, Kloster S, Knorr W, Nieradzik L, Spessa A, Folberth GA, Sheehan T, Voulgarakis A, Prentice IC, Sitch S, Kaplan JO, Harrison S, Arneth Aet al., 2016,

    The Fire Modeling Intercomparison Project (FireMIP), phase 1: Experimental and analytical protocols

    , Geoscientific Model Development, Vol: 9, ISSN: 1991-959X

    The important role of fire in regulating vegetation community composition and contributions to emissions of greenhouse gases and aerosols make it a critical component of dynamic global vegetation models and Earth system models. Over two decades of development, a wide variety of model structures and mechanisms have been designed and incorporated into global fire models, which have been linked to different vegetation models. However, there has not yet been a systematic examination of how these different strategies contribute to model performance. Here we describe the structure of the first phase of the Fire Model Intercomparison Project (FireMIP), which for the first time seeks to systematically compare a number of models. By combining a standardized set of input data and model experiments with a rigorous comparison of model outputs to each other and to observations, we will improve the understanding of what drives vegetation fire, how it can best be simulated, and what new or improved observational data could allow better constraints on model behavior. Here we introduce the fire models used in the first phase of FireMIP, the simulation protocols applied, and the benchmarking system used to evaluate the models. The works published in this journal are distributed under the Creative Commons Attribution 3.0 License. This license does not affect the Crown copyright work, which is re-usable under the Open Government Licence (OGL). The Creative Commons Attribution 3.0 License and the OGL are interoperable and do not conflict with, reduce, or limit each other.
  • Conference paper
    Pickering JC, Clear C, Liggins F, Belmonte MT, Thorne APet al., 2016,

    High resolution fourier transform spectrometry of astrophysically important elements from IR to VUV

    Modern astronomical spectrographs continue to require accurate high resolution atomic data for interpretation of many astrophysical spectra. The Imperial College London laboratory astrophysics program using high resolution Fourier Transform spectrometry is described.
  • Conference paper
    Palchetti L, Olivieri M, Pompei C, Labate D, Brindley H, Natale GD, Bianchini Get al., 2016,

    The Far Infrared FTS for the FORUM Mission

    A wide-band FTS has been designed to perform the spectral observation of the entire infrared Earth's outgoing emission, including the far infrared portion, for the FORUM space mission.
  • Journal article
    Ceppi P, Hartmann DL, 2016,

    Clouds and the Atmospheric Circulation Response to Warming

    , JOURNAL OF CLIMATE, Vol: 29, Pages: 783-799, ISSN: 0894-8755
  • Journal article
    Vanniere B, Czaja A, Dacre H, Woollings T, Parfitt Ret al., 2016,

    A Potential Vorticity Signature for the Cold Sector of Winter Extratropical Cyclones

    , Quarterly Journal of the Royal Meteorological Society, Vol: 142, Pages: 432-442, ISSN: 1477-870X

    The cold sector of mid-latitude storms is characterised by distinctive features such as strong surface heat fluxes, shallow convection, convective precipitation and synoptic subsidence. In order to evaluate the contribution of processes occurring in the cold sector to the mean climate, an appropriate indicator is needed. This study describes the systematic presence of negative PV behind the cold front of extratropical storms in winter. The origin of this negative PV is analysed using ERA-Interim data, potential vorticity tendencies averaged over the depth of the boundary layer are evaluated. It is found that negative PV is generated by diabatic processes in the cold sector and by Ekman pumping at the low centre, whereas positive PV is generated by Ekman advection of potential temperature in the warm sector. We suggest here that the negative PV at low-levels can be used to identify the cold sector. A PV-based indicator is applied to estimate the respective contributions of the cold sector and the remainder of the storm to upward motion, and large scale and convective precipitation. We compare the PV-based indicator with other distinctive features that could be used as markers of the cold sector, and find that potential vorticity is the best criterion when taken alone, and the best when combined with any other.
  • Journal article
    Martinovic MM, Zaslavsky A, Maksimovic M, Meyer-Vernet N, Segan S, Zouganelis I, Salem C, Pulupa M, Bale SDet al., 2016,

    Quasi-thermal noise measurements on STEREO: Kinetic temperature deduction using electron shot noise model

    , JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 121, Pages: 129-139, ISSN: 2169-9380
  • Journal article
    Southwood DJ, 2016,

    Space in 150 years: From fantasy through fiction to fact and function

    , Aeronautical Journal, Vol: 120, Pages: 201-208, ISSN: 0001-9240

    In the last century and half, space has moved from the realm of fantasy to everyday reality.In parallel the way space has been regarded by the person in the street and the ideas of whataccess to space might be used for have evolved extraordinarily.
  • Conference paper
    Franci L, Hellinger P, Matteini L, Verdini A, Landi Set al., 2016,

    Two-dimensional Hybrid Simulations of Kinetic Plasma Turbulence: Current and Vorticity vs Proton Temperature

    , 14th International Solar Wind Conference (Solar Wind), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Book chapter
    Badman SV, Branduardi-Raymont G, Galand M, Hess SLG, Krupp N, Lamy L, Melin H, Tao Cet al., 2016,

    Auroral Processes at the Giant Planets: Energy Deposition, Emission Mechanisms, Morphology and Spectra

    , MAGNETODISCS AND AURORAE OF GIANT PLANETS, Editors: Szego, Achilleos, Arridge, Badman, Delamere, Grodent, Kivelson, Louarn, Publisher: SPRINGER, Pages: 99-179, ISBN: 978-1-4939-3394-5
  • Conference paper
    Tao J, Wang L, Zong Q, Li G, Salem CS, Wimmer-Schweingruber RF, He J, Tu C, Bale SDet al., 2016,

    Solar Wind ∼0.1-1.5 keV Electrons at Quiet Times

    , 14th International Solar Wind Conference (Solar Wind), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Journal article
    group ISOSISOS, Holt P, Rhodes A, Wilson M, Ferguson M, Macmahon M, Gillespie D, Phillips K, Reynolds J, Kerridge R, Bennett M, Stewart M, Hartmann A, Jacobs T, Ortega D, Dias F, Machado M, Garcia J, Lopes M, Carr A, Yu HC, Rowe B, Sampson S, George R, Jones P, Tran D, Dobson G, Hall R, Lee E, Tsui A, Choi S, Dwyer H, McCartney C, Carroll J, Huang Y, Cao Y, Gao H, Hu T, Yang J, Yang Y, Zhong Y, Zhou J, He M, Li X, Wang H, Chen L, Wang L, Cai Y, Li Y, Sun H, Wang S, Wang Z, Wang K, Zhu Y, Du X, Fu Y, Huang L, Huang Y, Wang Z, Wang G, Wang S, Zhang Y, Zhang X, Chen C, Wang W, Liu Z, Fan L, Tang J, Chen Y, Chen Y, Huang C, Shen J, Wang J, Yang Q, Zhou H, Chen J, Chen Z, Li X, Zhang X, Bi Y, Cao J, Lin H, Liu Y, Sun C, Sun Y, Wang Y, Wang S, Zhang M, Shen Z, Zhang Y, Zhao B, Zhou X-J, Chen Q, Guo H, Guo Y, Qi Y, Zhang W, Zheng L, Chen Y, Chen Y, Hu X, Li X, Shen C, Sun Y, Wang Y, Wang D, Wu C, Xu L, Yuan J, Zhang L, Zhang H, Zhang Y, Zhao J, Zhao C, Zhou H, Zhou C, Chen H, Chen S, He J, Li C, Li H, Pan Y, Shi Y, Wu S, Zhang K, Zhao B, Chen F, Lin X, Liu G, Tao J, Yang L, Zhou J, Chen F, Cheng Z, Feng Y, Hou B, Hu CH, Huang H, Huang J, Jiang Z, Li M, Lin J, Liu M, Liu W, Liu Z, Ma L, Min J, Song Z, Xiong Y, Xu L, Yang S, Zhang Q, Zhang H, Zhang H, Zhang X, Zhao W, Zhao W, Zhu X, Chen L, Chen S, Dai Q, Han K, He X, Huang L, Jia D, Jin S, Li Q, Luo S, Pan Y, Qian M, Qin J, Shi Y, Wang J, Wang J, Wang L, Yan Y, Yao Y, Zhang M, Zhao J, He L, Huang L, Li Z, Li H, Li Y, Li L, Yuan Y, Zhang E, Zhang J, Zhao S, Chen C, Li J, Wen Z, Yu Y, Yuan F, Hu X, Zhang Y, Xiao W, Zhu Z, Dai Q, Fu K, Hu R, Hu X, Huang S, Li Y, Liang Y, Yu S, Guo Z, Wu J, Zhang R, Zhao X, Li Y, Liu C-X, Liu F-F, Ren W, Wang X-L, Xu G-J, Li B, Ou Y, Tang Y, Yao S, Zhang S, Kong C-C, Liu B, Wang T, Xiao W, Lu B, Xia Y, Zhou J, Hu S, Wang H, Hu L, Li B, Liu Q, Liu Y, Qiu X, Ren Q, Tong Y, Wang J, Xia J, Xiong X, Xu S, Yang T, Yuan J, Zhang B, Chen S, Fan Y, Fu S, Ge X, Guo B, Huang W, Jiang L, Jiang X, Liu Y, Paet al., 2016,

    Global patient outcomes after elective surgery: Prospective cohort study in 27 low-, middle- and high-income countries

    , British Journal of Anaesthesia, ISSN: 0007-0912
  • Conference paper
    Yang L, Wang L, Li G, He J, Salem CS, Tu C, Wimmer-Schweingruber RF, Bale SDet al., 2016,

    The Angular Distribution of Solar Wind ∼20-200 keV Superhalo Electrons at Quiet Times

    , 14th International Solar Wind Conference (Solar Wind), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Book chapter
    Turnbull JC, Graven H, Krakauer NY, 2016,

    Radiocarbon in the Atmosphere

    , RADIOCARBON AND CLIMATE CHANGE: MECHANISMS, APPLICATIONS AND LABORATORY TECHNIQUES, Editors: Schuur, Druffel, Trumbore, Publisher: SPRINGER INTERNATIONAL PUBLISHING AG, Pages: 83-137, ISBN: 978-3-319-25641-2
  • Journal article
    Mistry R, Eastwood JP, Hietala H, 2015,

    Development of bifurcated current sheets in solar wind reconnection exhausts

    , Geophysical Research Letters, Vol: 42, Pages: 10513-10520, ISSN: 1944-8007

    Petschek-type reconnection is expected to result in bifurcations of reconnection current sheets. In contrast, Hall reconnection simulations show smooth changes in the reconnecting magnetic field. Here we study three solar wind reconnection events where different spacecraft sample oppositely directed reconnection exhausts from a common reconnection site. The spacecraft's relative separations and measurements of the exhaust width are used to geometrically calculate each spacecraft's distance from the X line. We find that in all cases spacecraft farthest from the X line observe clearly bifurcated reconnection current sheets, while spacecraft nearer to the X line do not. These observations suggest that clear bifurcations of reconnection current sheets occur at large distances from the X line (~1000 ion skin depths) and that Petschek-type signatures are less developed close to the reconnection site. This may imply that fully developed bifurcations of reconnection current sheets are unlikely to be observed in the near-Earth magnetotail.
  • Journal article
    Odelstad E, Eriksson AI, Edberg NJT, Johansson F, Vigren E, Andre M, Tzou CY, Carr CM, Cupido Eet al., 2015,

    Evolution of the plasma environment of comet 67P from spacecraft potential measurements by the Rosetta Langmuir probe instrument

    , Geophysical Research Letters, Vol: 42, Pages: 10126-10134, ISSN: 1944-8007

    We study the evolution of the plasma environment of comet 67P using measurements of the spacecraft potential from early September 2014 (heliocentric distance 3.5 AU) to late March 2015 (2.1 AU) obtained by the Langmuir probe (RPC-LAP) instrument. The low collision rate keeps the electron temperature high (~ 5 eV), resulting in a negative spacecraft potential whose magnitude depends on the electron density. This potential is more negative in the northern (summer) hemisphere, particularly over sunlit parts of the neck region on the nucleus, consistent with neutral gas measurements by ROSINA-COPS. Assuming constant electron temperature, the spacecraft potential traces the electron density. This increases as the comet approaches the Sun, most clearly in the southern hemisphere by a factor possibly as high as 20 - 44 between September 2014 and January 2015. The northern hemisphere plasma density increase stays around a factor of around or below 8 - 12, consistent with seasonal insolation change.
  • Journal article
    Archer MO, Hartinger MD, Walsh BM, Plaschke F, Angelopoulos Vet al., 2015,

    Frequency variability of standing Alfven waves excited by fast mode resonances in the outer magnetosphere

    , Geophysical Research Letters, Vol: 42, Pages: 10150-10159, ISSN: 0094-8276

    Coupled fast mode resonances (cFMRs) in the outer magnetosphere, between the magnetopause and a turning point, are often invoked to explain observed discrete frequency field line resonances. We quantify their frequency variability, applying cFMR theory to a realistic magnetic field model and magnetospheric density profiles observed over almost half a solar cycle. Our calculations show that cFMRs are most likely around dawn, since the plasmaspheric plumes and extended plasmaspheres often found at noon and dusk can preclude their occurrence. The relative spread (median absolute deviation divided by the median) in eigenfrequencies is estimated to be 28%, 72%, and 55% at dawn, noon, and dusk, respectively, with the latter two chiefly due to density. Finally, at dawn we show that the observed bimodal density distribution results in bimodal cFMR frequencies, whereby the secondary peaks are consistent with the so-called “CMS” frequencies that have previously been attributed to cFMRs.
  • Journal article
    Regoli LH, Roussos E, Feyerabend M, Jones GH, Krupp N, Coates AJ, Simon S, Motschmann U, Dougherty MKet al., 2015,

    Access of energetic particles to Titan's exobase: A study of Cassini's T9 flyby

    , Planetary and Space Science, Vol: 130, Pages: 40-53, ISSN: 1873-5088

    We study how the local electromagnetic disturbances introduced by Titan affect the ionization rates of the atmosphere. For this, we model the precipitation of energetic particles, specifically hydrogen and oxygen ions with energies between 1 keV and 1 MeV, into Titan׳s exobase for the specific magnetospheric configuration of the T9 flyby. For the study, a particle tracing software package is used which consists of an integration of the single particle Lorentz force equation using a 4th order Runge–Kutta numerical method. For the electromagnetic disturbances, the output of the A.I.K.E.F. hybrid code (kinetic ions, fluid electrons) is used, allowing the possibility of analyzing the disturbances and asymmetries in the access of energetic particles originated by their large gyroradii. By combining these methods, 2D maps showing the access of each set of particles were produced. We show that the access of different particles is largely dominated by their gyroradii, with the complexity of the maps increasing with decreasing gyroradius, due to the larger effect that local disturbances introduced by the presence of the moon have in the trajectory of the particles with lower energies. We also show that for particles with gyroradii much larger than the moon׳s radius, simpler descriptions of the electromagnetic environment can reproduce similar results to those obtained when using the full hybrid simulation description, with simple north–south fields being sufficient to reproduce the hybrid code results for O+ ions with energies larger than 10 keV but not enough to reproduce those for H+ ions at any of the energies covered in the present study. Finally, by combining the maps created with upstream plasma flow measurements by the MIMI/CHEMS instrument, we are able to estimate normalized fluxes arriving at different selected positions of the moon׳s exobase. We then use these fluxes to calculate energy deposition and non-dissociative N2 ionization rates for precipitati
  • Journal article
    Russell AJB, Yeates AR, Eastwood JP, 2015,

    Magnetic reconnection now and in the future

    , Astronomy and Geophysics, Vol: 56, ISSN: 1366-8781
  • Journal article
    Tinetti G, Drossart P, Eccleston P, Hartogh P, Isaak K, Linder M, Lovis C, Micela G, Ollivier M, Puig L, Ribas I, Snellen I, Swinyard B, Allard F, Barstow J, Cho J, Coustenis A, Cockell C, Correia A, Decin L, de Kok R, Deroo P, Encrenaz T, Forget F, Glasse A, Griffith C, Guillot T, Koskinen T, Lammer H, Leconte J, Maxted P, Mueller-Wodarg I, Nelson R, North C, Palle E, Pagano I, Piccioni G, Pinfield D, Selsis F, Sozzetti A, Stixrude L, Tennyson J, Turrini D, Zapatero-Osorio M, Beaulieu J-P, Grodent D, Guedel M, Luz D, Norgaard-Nielsen HU, Ray T, Rickman H, Selig A, Swain M, Banaszkiewicz M, Barlow M, Bowles N, Branduardi-Raymont G, du Foresto VC, Gerard J-C, Gizon L, Hornstrup A, Jarchow C, Kerschbaum F, Kovacs G, Lagage P-O, Lim T, Lopez-Morales M, Malaguti G, Pace E, Pascale E, Vandenbussche B, Wright G, Ramos Zapata G, Adriani A, Azzollini R, Balado A, Bryson I, Burston R, Colome J, Crook M, Di Giorgio A, Griffin M, Hoogeveen R, Ottensamer R, Irshad R, Middleton K, Morgante G, Pinsard F, Rataj M, Reess J-M, Savini G, Schrader J-R, Stamper R, Winter B, Abe L, Abreu M, Achilleos N, Ade P, Adybekian V, Affer L, Agnor C, Agundez M, Alard C, Alcala J, Allende Prieto C, Alonso Floriano FJ, Altieri F, Alvarez Iglesias CA, Amado P, Andersen A, Aylward A, Baffa C, Bakos G, Ballerini P, Banaszkiewicz M, Barber RJ, Barrado D, Barton EJ, Batista V, Bellucci G, Belmonte Aviles JA, Berry D, Bezard B, Biondi D, Blecka M, Boisse I, Bonfond B, Borde P, Boerner P, Bouy H, Brown L, Buchhave L, Budaj J, Bulgarelli A, Burleigh M, Cabral A, Capria MT, Cassan A, Cavarroc C, Cecchi-Pestellini C, Cerulli R, Chadney J, Chamberlain S, Charnoz S, Jessen NC, Ciaravella A, Claret A, Claudi R, Coates A, Cole R, Collura A, Cordier D, Covino E, Danielski C, Damasso M, Deeg HJ, Delgado-Mena E, Del Vecchio C, Demangeon O, De Sio A, De Wit J, Dobrijevic M, Doel P, Dominic C, Dorfi E, Eales S, Eiroa C, Espinoza Contreras M, Esposito M, Eymet V, Fabrizio N, Fernandez M, Femena Castella B, Figueira Pet al., 2015,

    The EChO science case

    , Experimental Astronomy, Vol: 40, Pages: 329-391, ISSN: 1572-9508

    The discovery of almost two thousand exoplanets has revealed an unexpectedlydiverse planet population. We see gas giants in few-day orbits, whole multi-planet systemswithin the orbit of Mercury, and new populations of planets with masses between that of theEarth and Neptune—all unknown in the Solar System. Observations to date have shown thatour Solar System is certainly not representative of the general population of planets in ourMilky Way. The key science questions that urgently need addressing are therefore: What areexoplanets made of? Why are planets as they are? How do planetary systems work and whatcauses the exceptional diversity observed as compared to the Solar System? The EChO(Exoplanet Characterisation Observatory) space mission was conceived to take up thechallenge to explain this diversity in terms of formation, evolution, internal structure andplanet and atmospheric composition. This requires in-depth spectroscopic knowledge of theatmospheres of a large and well-defined planet sample for which precise physical, chemicaland dynamical information can be obtained. In order to fulfil this ambitious scientificprogram, EChO was designed as a dedicated survey mission for transit and eclipsespectroscopy capable of observing a large, diverse and well-defined planet sample withinits 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signalfrom the star and planet are differentiated using knowledge of the planetary ephemerides,allows us to measure atmospheric signals from the planet at levels of at least 10−4 relative tothe star. This can only be achieved in conjunction with a carefully designed stable payloadand satellite platform. It is also necessary to provide broad instantaneous wavelengthcoverage to detect as many molecular species as possible, to probe the thermal structureof the planetary atmospheres and to correct for the contaminating effects of the stellarphotosphere. This requires wavelength coverage of at l
  • Journal article
    Weller E, Min S-K, Lee D, Cai W, Yeh S-W, Kug J-Set al., 2015,

    HUMAN CONTRIBUTION TO THE 2014 RECORD HIGH SEA SURFACE TEMPERATURES OVER THE WESTERN TROPICAL AND NORTHEAST PACIFIC OCEAN

    , BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY, Vol: 96, Pages: S100-S104, ISSN: 0003-0007
  • Journal article
    Russell AJB, Yeates AR, Eastwood JP, 2015,

    Magnetic reconnection now and in the future

    , ASTRONOMY & GEOPHYSICS, Vol: 56, Pages: 18-23, ISSN: 1366-8781
  • Journal article
    Arridge CS, Eastwood J, Jackman CM, Poh GK, Slavin JA, Thomsen MF, Andre N, Jia X, Kidder A, Lamy L, Radioti A, Reisenfeld DB, Sergis N, Volwerk M, Walsh AP, Zarka P, Coates AJ, Dougherty MKet al., 2015,

    Cassini in situ observations of long duration magnetic reconnection in Saturn’s magnetotail

    , Nature Physics, Vol: 12, Pages: 268-271, ISSN: 1745-2481

    Magnetic reconnection is a fundamental process in solar system and astrophysical plasmas, through which stored magnetic energy associated with current sheets is converted into thermal, kinetic and wave energy1, 2, 3, 4. Magnetic reconnection is also thought to be a key process involved in shedding internally produced plasma from the giant magnetospheres at Jupiter and Saturn through topological reconfiguration of the magnetic field5, 6. The region where magnetic fields reconnect is known as the diffusion region and in this letter we report on the first encounter of the Cassini spacecraft with a diffusion region in Saturn’s magnetotail. The data also show evidence of magnetic reconnection over a period of 19 h revealing that reconnection can, in fact, act for prolonged intervals in a rapidly rotating magnetosphere. We show that reconnection can be a significant pathway for internal plasma loss at Saturn6. This counters the view of reconnection as a transient method of internal plasma loss at Saturn5, 7. These results, although directly relating to the magnetosphere of Saturn, have applications in the understanding of other rapidly rotating magnetospheres, including that of Jupiter and other astrophysical bodies.
  • Journal article
    Walker SN, Balikhin MA, Shklyar DR, Yearby KH, Canu P, Carr CM, Dandouras Iet al., 2015,

    Experimental determination of the dispersion relation of magnetosonic waves

    , Journal of Geophysical Research: Space Physics, Vol: 120, Pages: 9632-9650, ISSN: 2169-9402

    Magnetosonic waves are commonly observed in the vicinity of the terrestrial magnetic equator. It has been proposed that within this region they may interact with radiation belt electrons, accelerating some to high energies. These wave-particle interactions depend upon the characteristic properties of the wave mode. Hence determination of the wave properties is a fundamental part of understanding these interaction processes. Using data collected during the Cluster Inner Magnetosphere Campaign, this paper identifies an occurrence of magnetosonic waves, discusses their generation and propagation properties from a theoretical perspective, and utilises multispacecraft measurements to experimentally determine their dispersion relation. Their experimental dispersion is found to be in accordance with that based on cold plasma theory.
  • Journal article
    Field RD, Luo M, Kim D, Del Genio AD, Voulgarakis A, Worden Jet al., 2015,

    Sensitivity of simulated tropospheric CO to subgrid physics parameterization: a case study of Indonesian biomass burning emissions in 2006

    , Journal of Geophysical Research: Atmospheres, Vol: 120, Pages: 11743-11759, ISSN: 2169-8996

    Recent cumulus and turbulence parameterization changes to the NASA GISS ModelE2 have improved representation of the Madden-Julian Oscillation and low cloud distribution, but their effect on composition-related quantities is not known. In this study, we simulate the vertical transport of carbon monoxide (CO) from uncontrolled biomass burning in Indonesia in late 2006, during which uniquely high CO was detected in the upper troposphere. Two configurations of ModelE2, one without the changes (AR5) and one with the changes (AR5′), are used for an ensemble simulation of the transport of CO from the biomass burning. The simulation results are evaluated against new CO profiles retrieved jointly from the Aura Tropospheric Emission Spectrometer and the Microwave Limb Sounder. Modeled upper tropospheric CO using the AR5 physics was unrealistically high. The AR5′ physics suppress deep convection that reaches near the tropopause, reducing vertical transport of CO to the upper troposphere and bringing the model into better agreement with satellite CO. In this regard, the most important changes were related to the strength of entrainment of environmental air into the convective column, the strength of re-evaporation above cloud base, and a negative plume buoyancy threshold based on density temperature. This study illustrates how individual, noncomposition model changes can lead to significantly different modeled composition, which in this case improved agreement with satellite retrievals. This study also illuminates the potential usefulness of CO satellite observations in constraining unobservable processes in general circulation models.
  • Journal article
    Provan G, Tao C, Cowley SWH, Dougherty MK, Coates AJet al., 2015,

    Planetary period oscillations in Saturn's magnetosphere: Examining the relationship between abrupt changes in behavior and solar wind-induced magnetospheric compressions and expansions

    , Journal of Geophysical Research: Space Physics, Vol: 120, Pages: 9524-9544, ISSN: 2169-9402

    We examine planetary period oscillations (PPOs) observed in Saturn's magnetospheric magnetic field data from the time of Saturn's equinox in 2009. In particular, we focus on the time period commencing February 2011, when the oscillations started to display sudden and unexpected changes in behavior at ~100–200 day intervals. These were characterized by large simultaneous changes in the amplitude of the northern and southern PPO systems, together with small changes in period and jumps in phase. Nine significant abrupt changes have been observed in the postequinox interval to date, commencing as the Sun started to emerge from a long extended solar minimum. We perform a statistical study to determine whether these modulations in PPO behavior were associated with changes in the solar and/or upstream solar wind conditions. We report that the upstream solar wind conditions show elevated values of solar wind dynamic pressure and density around the time of PPO behavioral transitions, as opposed to before and after these times. We suggest that abrupt changes in PPO behavior may be related to significant changes in the size of the Saturnian magnetosphere in response to varying solar wind conditions.

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