Publications


Environmental predictions for the Beagle 2 lander, based on GCM climate simulations

Planetary and Space Science 52 (2004) 259-269

SJ Bingham, SR Lewis, CE Newman, PL Read

The Mars climate database (MCD) is a database of statistics based on output from physically consistent numerical model simulations which describe the climate and surface environment of Mars. It is used here to predict the meteorological environment of the Beagle 2 lander site. The database was constructed directly on the basis of output from multiannual integrations of two general circulation models, developed jointly at Laboratoire de Météorologie Dynamique du Centre National de la Recherche Scientifique, France, and the University of Oxford, UK. In an atmosphere with dust opacities similar to that observed by Mars Global Surveyor, the predicted surface temperature at the time of landing (Ls=322°, 13:00 local time), is ∼267 K, and varying between ∼186 and 268 K over the Martian day. The predicted air temperature at 1 m above the surface, the height of the fully extended Beagle 2 robot arm, is ∼258 K at the time of landing. The expected mean wind near the surface on landing is ∼5 ms-1 north-westerly in direction, becoming more southerly over the mission. An increase in mean surface pressure is expected during the mission. Heavy global dust storm predictions are discussed; conditions which may only occur in the extreme as the expected time of landing is around the end of the main dust storm period. Past observations show approximately a one in five chance of a large-scale dust storm in a whole Mars year over the landing region, Isidis Planitia. This statistic results from observations of global, encircling, regional and local dust storms but does not include any small-scale dust "events" such as dust devils. © 2003 Elsevier Ltd. All rights reserved.


A new general circulation model of Jupiter's atmosphere based on the UKMO Unified Model: three-dimentional evolution of isolated vortices and zonal jets in mid-latitudes

Planetary and Space Science 52 (2004) 423-445

Y Yamazaki, D.R. Skeet, P.L. Read


Hydrothermal plume dynamics on Europa: Implications for chaos formation

Journal of Geophysical Research E: Planets 109 (2004)

JC Goodman, GC Collins, J Marshall, RT Pierrehumbert

Hydrothermal plumes may be responsible for transmitting radiogenic or tidally generated heat from Europa's rocky interior through a liquid ocean to the base of its ice shell. This process has been implicated in the formation of chaos regions and lenticulae by melting or exciting convection in the ice layer. In contrast to earlier work, we argue that Europa's ocean should be treated as an unstratified fluid. We have adapted and expanded upon existing work describing buoyant plumes in a rotating, unstratified environment. We discuss the scaling laws governing the flow and geometry of plumes on Europa and perform a laboratory experiment to obtain scaling constants and to visualize plume behavior in a Europa-like parameter regime. We predict that hydrothermal plumes on Europa are of a lateral scale (at least 25-50 km) comparable to large chaos regions; they are too broad to be responsible for the formation of individual lenticulae. Plume heat fluxes (0.1-10 W/m2) are too weak to allow complete melt-through of the ice layer. Current speeds in the plume (3-8 mm/s) are much slower than indicated by previous studies. The observed movement of ice blocks in the Conamara Chaos region is unlikely to be driven by such weak flow. Copyright 2004 by the American Geophysical Union.


Hydrothermal plume dynamics on Europa: Implications for chaos formation

JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS 109 (2004) ARTN E03008

JC Goodman, GC Collins, J Marshall, RT Pierrehumbert


Predicting weather conditions and climate for Mars expeditions

JBIS-J BRIT INTERPLA 57 (2004) 75-86

PL Read, SR Lewis, SJ Bingham, CE Newman

Weather and climatic conditions are among the most important factors to be taken into account when planning expeditions to remote and challenging locations on Earth. This is likely to be equally the case for expedition planners on Mars, where conditions (in terms of extremes of temperature, etc.) can be at least as daunting as back on Earth. With the success of recent unmanned missions to Mars, such as NASA's Mars Pathfinder, Mars Global Surveyor and Mars Odyssey, there is now a great deal of information available on the range of environmental conditions on Mars, from the tropics to the CO2 ice-covered polar caps. This has been further supplemented by the development of advanced numerical models of the Martian atmosphere, allowing detailed and accurate simulations and predictions of the weather and climate across the planet. This report discusses the main weather and climate variables which future Martian human expedition planners will need to take into account. The range of conditions likely to be encountered at a variety of typical locations on Mars is then considered, with reference to predictions from the ESA Mars Climate Database.


Upper atmosphere of Mars up to 120 km: Mars Global Surveyor accelerometer data analysis with the LMD general circulation model

JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS 109 (2004) ARTN E01011

MAI Coll, F Forget, MA Lopez-Valverde, PL Read, SR Lewis


Upper atmosphere of Mars up to 120 km: Mars Global Surveyor accelerometer data analysis with the LMD general circulation model

Journal of Geophysical Research E: Planets 109 (2004)

M Angelats i Coll, F Forget, MA López-Valverde, PL Read, SR Lewis

Mars Global Surveyor (MGS) aerobraking accelerometer density measurements are analyzed with the use of the general circulation model (GCM) at the Laboratoire de Météorologie Dynamique (LMD). MGS constant altitude density data are used, obtaining longitudinal wavelike structures at fixed local times which appear to be dominated by low zonal wave number harmonics. Comparisons with simulated data for different seasons and latitudinal bands at constant altitude are performed. Excellent agreement is obtained between the simulated and observational data for low latitudes, with accuracy in both mean and zonal structure. Higher latitudes show a reduction in agreement between GCM results and MGS data. Comparisons that result in good agreement with the observational data allow for the study of wave composition in the MGS data. In particular, the excellent agreement between the simulations and the data obtained at 115 km during areocentric longitude Ls ≈ 65° allows the extraction of the major contributors to the signature, with the eastward propagating diurnal waves of wave numbers one to three being the major players. Significant contributions are also obtained for eastward propagating semidiurnal waves of wave numbers two, three, and five and diurnal wave number five. A sensitivity study is performed to delineate the effects of the near-IR tidal forcing of the upper atmosphere on the wave content at those heights. Simulations without this forcing yield reduced amplitudes for diurnal eastward propagating waves two and three along with a more latitudinally symmetric response for these two components as well as for diurnal eastward propagating wave number one. Copyright 2004 by the American Geophysical Union.


An intense stratospheric jet on Jupiter

Nature 427 (2004) 132-135

SB Calcutt, Achtergerg, Flasar, Kunde


The Martian climate revisited

Springer Verlag, 2004

PL Read, SR Lewis

latest techniques of atmospheric modelling, The Martian Climate Revisited provides a comprehensive summary of our knowledge and current understanding of the meteorology and climate of Mars from the viewpoint of atmospheric scientists .


Stochastic resonance in a nonlinear model of a rotating, stratified shear flow, with a simple stochastic inertia-gravity wave parameterization

NONLINEAR PROCESSES IN GEOPHYSICS 11 (2004) 127-135

PD Williams, TWN Haine, PL Read


Spontaneous generation and impact of inertia-gravity waves in a stratified, two-layer shear flow

GEOPHYSICAL RESEARCH LETTERS 30 (2003) ARTN 2255

PD Williams, PL Read, TWN Haine


Glacial flow of floating marine ice in "Snowball Earth"

Journal of Geophysical Research: Oceans 108 (2003)

JC Goodman, RT Pierrehumbert

Simulations of frigid Neoproterozoic climates have not considered the tendency of thick layers of floating marine ice to deform and spread laterally. We have constructed a simple model of the production and flow of marine ice on a planetary scale, and determined ice thickness and flow in two situations: when the ocean is globally ice-covered ("hard snowball") and when the tropical waters remain open ("soft snowball"). In both cases, ice flow strongly affects the distribution of marine ice. Flowing ice probably carries enough latent heat and freshwater to significantly affect the transition into a Snowball Earth climate. We speculate that flowing marine ice, rather than continental ice sheets, may be the erosive agent that created some Neoproterozoic glacial deposits.


Glacial flow of floating marine ice in ''Snowball Earth''

JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 108 (2003) ARTN 3308

JC Goodman, RT Pierrehumbert


A combined laboratory and numerical study of heat transport by baroclinic eddies and axisymmetric flows

JOURNAL OF FLUID MECHANICS 489 (2003) 301-323

PL Read


Erratum: Decay of passive scalars under the action of single scale smooth velocity fields in bounded two-dimensional domains - From non-self-similar probability distribution functions to self-similar eigenmodes (Physical Review E (2002) 66 (056302))

Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 68 (2003) 199031-

J Sukhatme, RT Pierrehumbert


Decay of passive scalars under the action of single scale smooth velocity fields in bounded two-dimensional domains: From non-self-similar probability distribution functions to self-similar eigenmodes (vol E 66, art no 056302, 2002)

PHYSICAL REVIEW E 68 (2003) ARTN 019903

J Sukhatme, RT Pierrehumbert


Equatorial jets in the dusty Martian atmosphere

JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS 108 (2003) ARTN 5034

SR Lewis, PL Read


Reply to "Modern precipitation stable isotope vs. elevation gradients in the High Himalaya" by Hou Shugui et al.

EARTH AND PLANETARY SCIENCE LETTERS 209 (2003) 401-403

DB Rowley, BS Currie, RT Pierrehumbert


Equatorial jets in the dusty Martian atmosphere

Journal of Geophysical Research E: Planets 108 (2003)

SR Lewis, PL Read

We investigate the production of equatorial jets which demostrate strong local superrotation in an atmospheric general circulation model of Mars. These westerly jets are driven by diurnal thermal tides, and their strength is shown to be closely related to the amount of dust in the atmosphere. The superrotating jets are strongest near to equinox and under conditions of high atmospheric dust loading. If there is sufficient dust, in amounts corresponding to dust storm conditions, the westerly equatorial jets can occur at any time of year and reach speeds of over 40 m/s, peaking between 10 and 20 km altitude. For more moderate dust amounts, typical of background levels on Mars, the jets are still strong when the subsolar point is close to the equator and latitudinally symmetric tidal modes are forced. Strong easterly retrograde winds are also found high above the equator, and it is shown that the thermal tides play a major role in their formation. This process is especially relevant close to equinox when the cross-equatorial meridional circulation is weak.


Risk and reason: Safety, law, and the environment

NATURE 422 (2003) 263-263

RT Pierrehumbert

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