Suchergebnisse

We report on daytime limb observations of Mars upper atmosphere acquired by the OMEGA instrument on board the European spacecraft Mars Express. The strong emission observed at 4.3m is interpreted as due to CO2 fluorescence of solar radiation and is detected at a tangent altitude in between 60 and 110km. The main value of OMEGA observations is that they provide simultaneously spectral information and good spatial sampling of the CO2 emission. In this study we analyzed 98 dayside limb observations spanning over more than 3 Martian years, with a very good latitudinal and longitudinal coverage. Thanks to the precise altitude sounding capabilities of OMEGA, we extracted vertical profiles of the non-local thermodynamic equilibrium (non-LTE) emission at each wavelength and we studied their dependence on several geophysical parameters, such as the solar illumination and the tangent altitude. The dependence of the non-LTE emission on solar zenith angle and altitude follows a similar behavior to that predicted by the non-LTE model. According to our non-LTE model, the tangent altitude of the peak of the CO2 emission varies with the thermal structure, but the pressure level where the peak of the emission is found remains constant at approximate to 0.03 0.01Pa, . This non-LTE model prediction has been corroborated by comparing SPICAM and OMEGA observations. We have shown that the seasonal variations of the altitude of constant pressure levels in SPICAM stellar occultation retrievals correlate well with the variations of the OMEGA peak emission altitudes, although the exact pressure level cannot be defined with the spectroscopy for the investigation of the characteristics of the atmosphere of Venus (SPICAM) nighttime data. Thus, observed changes in the altitude of the peak emission provide us information on the altitude of the 0.03Pa pressure level. Since the pressure at a given altitude is dictated by the thermal structure below, the tangent altitude of the peak emission represents then an important piece of information of the atmosphere, of great value for validating general circulation models. We thus compared the altitude of OMEGA peak emission with the altitude of the 0.03Pa level predicted by the Laboratoire de meteorologie dynamique (LMD)-Mars global circulation model and found that the peak emission altitudes from OMEGA present a much larger variability than the tangent altitude of the 0.03Pa level predicted by the general circulation model. This variability could be possibly due to unresolved atmospheric waves. Further studies using this strong CO2 limb emission data are proposed. ; A.P. acknowledges funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement 246556.This work has received funding from the European Union's Horizon 2020 Programme (H2020-Compet-08-2014) under grant agreement UPWARDS-633127. ; Peer reviewed

Stiepen, A. et al. ; We report results from a study of nitric oxide nightglow over the northern hemisphere of Mars during winter, the southern hemisphere during fall equinox, and equatorial latitudes during summer in the northern hemisphere based on observations of the δ and γ bands between 190 and 270 nm by the Imaging UltraViolet Spectrograph (IUVS) on the Mars Atmosphere and Volatile EvolutioN mission (MAVEN) spacecraft. The emission reveals recombination of N and O atoms dissociated on the dayside of Mars and transported to the nightside. We characterize the brightness (from 0.2 to 30 kR) and altitude (from 40 to 115 km) of the NO nightglow layer, as well as its topside scale height (mean of 11 km). We show the possible impact of atmospheric waves forcing longitudinal variability, associated with an increased brightness by a factor of 3 in the 140–200° longitude region in the northern hemisphere winter and in the −102° to −48° longitude region at summer. Such impact to the NO nightglow at Mars was not seen before. Quantitative comparison with calculations of the LMD-MGCM (Laboratoire de Météorologie Dynamique-Mars Global Climate Model) suggests that the model globally reproduces the trends of the NO nightglow emission and its seasonal variation and also indicates large discrepancies (up to a factor 50 fainter in the model) in northern winter at low to middle latitudes. This suggests that the predicted transport is too efficient toward the night winter pole in the thermosphere by ∼20° latitude north. ©2017. American Geophysical Union. All Rights Reserved. ; A. Stiepen is supported by the Fund for Scientific Research (F.R.S.-FNRS). The MAVEN mission is supported by NASA through the Mars Exploration Program in association with the University of Colorado and NASA's Goddard Space Flight Center. M. Stevens is supported by the NASA MAVEN Participating Scientist program. B. Hubert and J.-C. Gerard acknowledge support from the SCOOP/BRAIN program of the Belgian Federal Government. A. Stiepen also thanks M. Dumont for her help in the finalization of the figures. F.G.-G. is funded by the European Union Horizon 2020 Programme (H2020 Compet-08-2014) under grant agreement UPWARDS-633127. ; Peer reviewed

We present a non-local thermodynamic equilibrium retrieval scheme for atmospheric composition and its application to Mars CO2 infrared limb emissions as measured by the OMEGA instrument on board Mars Express (MEx). These emissions are caused by CO2 fluorescence of solar radiation, and thus the retrieval scheme accounts for non-LTE processes. We analyzed the dayside limb observations from a selection of three OMEGA orbits or data qubes. Before the retrieval was applied, we performed a radiometric calibration, cleaned the spectra (including clustering techniques) and generated radiance vertical profiles for each dataset. We also present information on the inversion set up, results on the retrieved CO2 density profiles, as well as the temperature profiles derived from the CO2 densities by assuming hydrostatic equilibrium. An extensive sensitivity study of the retrieval scheme was carried out, including its application to the OMEGA spectra taken at different MEx orbital configurations, to conclude on its performance and to offer recommendations for its systematic use with MEx datasets. The uncertainty due to the instrumental Gain calibration and that caused by the retrieval noise error itself are of large importance for the inversion, but a comparable component of the total error comes from the uncertainties of the temperature provided by the GCM. We demonstrated that, between 120 and 160 km, CO2 profiles can be derived with a precision around 30% and a vertical resolution of about 15 km. © 2020 ; This work was conducted as part of the project UPWARDS-633127 under the European Union's Horizon 2020 research and innovation Programme. The IAA team was supported by grant PGC2018-101836-B-100 ( MCIU/AEI/FEDER, EU ) and by the Spanish MCIU through the 'Center of Excellence Severo Ochoa' award to the IAA/CSIC ( SEV-2017-0709 ). OMEGA data are publicly available via the ESA Planetary Science Archive. ; Peer reviewed

López-Valverde, M. A. et al. ; The Martian mesosphere and thermosphere, the region above about 60 km, is not the primary target of the ExoMars 2016 mission but its Trace Gas Orbiter (TGO) can explore it and address many interesting issues, either in-situ during the aerobraking period or remotely during the regular mission. In the aerobraking phase TGO peeks into thermospheric densities and temperatures, in a broad range of latitudes and during a long continuous period. TGO carries two instruments designed for the detection of trace species, NOMAD and ACS, which will use the solar occultation technique. Their regular sounding at the terminator up to very high altitudes in many different molecular bands will represent the first time that an extensive and precise dataset of densities and hopefully temperatures are obtained at those altitudes and local times on Mars. But there are additional capabilities in TGO for studying the upper atmosphere of Mars, and we review them briefly. Our simulations suggest that airglow emissions from the UV to the IR might be observed outside the terminator. If eventually confirmed from orbit, they would supply new information about atmospheric dynamics and variability. However, their optimal exploitation requires a special spacecraft pointing, currently not considered in the regular operations but feasible in our opinion. We discuss the synergy between the TGO instruments, specially the wide spectral range achieved by combining them. We also encourage coordinated operations with other Mars-observing missions capable of supplying simultaneous measurements of its upper atmosphere. © 2018, Springer Science+Business Media B.V., part of Springer Nature. ; The IAA/CSIC team has been supported by the European Union's Horizon 2020 Programme (H2020-Compet-08-2014) under grant agreement UPWARDS-633127, by CSIC Proyecto Intramural 201450E022 and by the Plan Nacional del Espacio ESP2015-65064-C2-1-P (MINECO/FEDER). This research was partly supported by the SCOOP/BRAIN program of the Belgian Science Policy Office (BELSPO). We acknowledge the work of Sabrina Guilbon during her Master internship at LATMOS on the development of the technique to compare the slant profiles of SPICAM and the LMD GCM. M.R.P. thanks UKSA for support under grant ST/I003061/1 and ST/P001262/1. C.F.W. acknowledges funding support from the UK Space Agency. Work by A.K., D.J.MC. and D.M.K. at the Jet Propulsion Laboratory, California Institute of Technology was performed under a contract with the National Aeronautics and Space Administration. OK, NI and AF thanks funding from Roscosmos for the ACS operation support and science funding from The Federal Agency of scientific organization (Planeta No. 0028-2014-0004). ; Peer reviewed

NOMAD (Nadir and Occultation for MArs Discovery) is one of the four instruments on board the ExoMars Trace Gas Orbiter, scheduled for launch in March 2016. It consists of a suite of three high-resolution spectrometers - SO (Solar Occultation), LNO (Limb, Nadir and Occultation) and UVIS (Ultraviolet and Visible Spectrometer). Based upon the characteristics of the channels and the values of Signal-to-Noise Ratio obtained from radiometric models discussed in (Vandaele et al., 2015a, 2015b; Thomas et al., 2016), the expected performances of the instrument in terms of sensitivity to detection have been investigated. The analysis led to the determination of detection limits for 18 molecules, namely CO, HO, HDO, CH, CH, CH, HCO, CH, SO, HS, HCl, HCN, HO, NH, NO, NO, OCS, O. NOMAD should have the ability to measure methane concentrations Inter-university Attraction Poles> programme financed by the Belgian Government (Planet TOPERS no P7-15) and a BRAIN Research Grant BR/143/A2/SCOOP. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement no. 607177 CrossDrive. UK funding is acknowledged under the UK Space Agency Grant ST/I003061/1. ; Peer Reviewed

NASA's InSight landed in Elysium Planitia (~4.5°N,136°E) at L ~ 296° (November 2018), right after the decay of the 2018 Global Dust Storm (GDS) and before the onset of the 2019 Large Dust Storm (LDS) at L ~ 320° (January 2019). InSight's cameras observed a rise in the atmospheric opacities during the storm from ~0.7 to ~1.9, similarly to contemporaneous measurements by Curiosity in Gale crater. Pressure tides were strongly affected at the locations of InSight and Curiosity. In particular, the diurnal pressure mode experienced an abrupt increase during the onset of the LDS, similar to that measured by Curiosity, most likely due to longitudinally asymmetric dust loading. Later, the dust was redistributed around the planet and the semidiurnal mode evolved according to dust opacity in both missions. Before and after the onset of the storm, the observed wind patterns resulted from the interaction between regional and local slope flows induced by topography, which all produced a diurnal perturbation superimposed on a mean flow, dominated by the Hadley cell but with modifications due to channeling effects from the regional topography. However, the onset of the LDS modified this to a scenario consistent with enhanced tidal flows. The local air temperatures are strongly perturbed by the lander's thermal effects, and their retrieval significantly depends on wind patterns, which changed during the course of the dust storm. Observations suggest a decrease in convective vortices during the dust storm; however, vortex activity remained strong during the storm's onset due to the increase in wind speeds. ; With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

Marte es un mundo vasto y complejo. Un planeta rojizo, debido a su superficie, ampliamente cubierta por polvo y rocas de óxido férrico. Marte tiene una atmósfera tenue, principalmente compuesta por dióxido de carbono (CO2), con circulación atmosférica y patrones climáticos, como la Tierra. Sin embargo, tiene destacadas oscilaciones diurnas de viento, debido a una excursión térmica considerable. Las oscilaciones tienen un efecto en todas las capas de la atmósfera, y ejercen una influencia apreciable sobre el resto de la circulación atmosférica global de Marte. En la ultima década, varias misiones han viajado al Planeta Rojo y algunas más han sido aprobadas para ser lanzadas en los próximos años. Dos de estas misiones han sido diseñadas, construidas y operadas por/desde Europa, y son especialmente relevantes para esta Tesis: Mars Express y ExoMars ; Tesis Univ. Granada. ; This work was conducted as part of the project UPWARDS-633127 under the European Union's Horizon 2020 research and innovation Programme. The IAA team was supported by the Spanish Ministry of Economy, Industry and Competitiveness and by FEDER funds under grant ESP2015-65064-C2-1-P (MINECO/FEDER)

1 Mars in the Solar System -- 1.1 The orbit and movements of Mars -- 1.2 Dimensions and mass -- 1.3 The Martian seasons -- 1.4 The pattern of discovery -- 1.5 Albedo markings -- 2 Spacecraft Exploration Of The Red Planet -- 2.1 Early Mars missions -- 2.2 Mariner 9 -- 2.3 Soviet Mars exploration -- 2.4 The Viking missions -- 2.5 The Soviet Phobos mission -- 3 The Present Face of Mars -- 3.1 The topography of Mars -- 3.2 Physiographic provinces -- 3.3 Thermal inertia mapping -- 3.4 The stratigraphy of Mars -- 3.5 Summary -- 4 The Atmosphere and Weather -- 4.1 The composition of the atmosphere -- 4.2 Atmospheric pressure variations -- 4.3 Isotopic abundances in the atmosphere -- 4.4 Atmospheric circulation pattern -- 4.5 Clouds -- 5 The Interior of Mars -- 5.1 Introduction -- 5.2 The figure and gravity of Mars -- 5.3 Internal density profile -- 5.4 Composition of the interior -- 5.5 Differentiation of the Martian crust -- 6 The Ancient Cratered Terrain -- 6.1 Introduction -- 6.2 The Martian cratering record -- 6.3 Martian impact basins -- 6.4 Morphology of impact craters -- 6.5 Crater ejecta morphology -- 6.6 Channelling on the cratered plateau -- 6.7 Intercrater plains -- 6.8 Volcanoes of the cratered plateau -- 6.9 The geological story as revealed by the upland rocks -- 7 The Central Volcanoes of Mars -- 7.1 Introduction -- 7.2 Volcano distribution -- 7.3 Classification of volcano types -- 7.4 Volcano ages -- 7.5 Highland paterae -- 7.6 Shield volcanoes and paterae -- 7.7 Martian shields -- 7.8 Older Tharsis volcanoes -- 7.9 Alba Patera -- 7.10 The shield volcanoes of Elysium -- 7.11 Apollinaris Patera -- 7.12 Central volcanism on Mars -- 8 The Plains of Mars -- 8.1 Introduction -- 8.2 Noachian and Early Hesperian plains -- 8.3 Hesperian-age flow plains -- 8.4 The Medusae Fossae plains -- 8.5 Tempe Terra plains province -- 8.6 Volcanic plains of Amazonian age -- 8.7 Plains deposits of Hellas -- 8.8 The northern plains -- 8.9 Plains and major resurfacing events in Martian history -- 9 The Equatorial Canyons -- 9.1 General features of Valles Marineris -- 9.2 Details of canyon physiography -- 9.3 General form of canyon walls -- 9.4 Wall retreat and landslide deposits -- 9.5 Wall retreat - tributary canyon development -- 9.6 Interior deposits -- 9.7 Formation of the canyon system -- 10 Martian Channels and Chaotic Terrain -- 10.1 Introduction -- 10.2 Valley networks in the ancient cratered terrain -- 10.3 Outflow channels -- 10.4 Fretted channels -- 10.5 Chaotic terrain -- 11 The Polar Regions, Wind And Volatile Activity -- 11.1 Introduction -- 11.2 Nature of the polar caps -- 11.3 Laminated polar deposits -- 11.4 High-latitude plains and dune fields -- 11.5 Wind activity on Mars -- 12 The Geological History of Mars -- 12.1 Introduction -- 12.2 The tectonic history of Mars -- 12.3 The evolution of Tharsis -- 12.4 Some final thoughts concerning Tharsis -- 12.5 The crustal dichotomy -- 12.6 The geological development of Mars -- 12.7 Climatic and volatile history -- 13 The Next Steps -- 13.1 Future Mars missions -- 13.2 Climate and the search for life -- 13.3 Epilogue -- Appendices -- A Astronomical Data -- B Phobos and Deimos -- C Model Chronologies for Mars -- D Stratigraphy of Martian Geological Features and Units.

The recent suggestion of phosphine in Venus's atmosphere has regenerated interest in the idea of life in clouds. However, such analyses usually neglect the role of water activity, which is a measure of the relative availability of water, in habitability. Here we compute the water activity within the clouds of Venus and other Solar System planets from observations of temperature and water-vapour abundance. We find water-activity values of sulfuric acid droplets, which constitute the bulk of Venus's clouds, of ≤0.004, two orders of magnitude below the 0.585 limit for known extremophiles. Considering other planets, ice formation on Mars imposes a water activity of ≤0.537, slightly below the habitable range, whereas conditions are biologically permissive (>0.585) at Jupiter's clouds (although other factors such as their composition may play a role in limiting their habitability). By way of comparison, Earth's troposphere conditions are, in general, biologically permissive, whereas the atmosphere becomes too dry for active life above the middle stratosphere. The approach used in the current study can also be applied to extrasolar planets. ; We are grateful to S. L. Clegg (University of East Anglia, England, UK) for helpful discussions on the use of the E-AIM at low water activity and the provision of some code; C. S. Cockell (University of Edinburgh, Scotland, UK), D. Y. Sorokin (Winogradsky Institute of Microbiology, Russia) and A. Ventosa (University of Seville, Spain) for providing information about thermotolerance of halophiles; M. S. Marley (NASA Ames Research Center, CA, USA) for information on Jupiter and exoplanets; A. Méndez (University of Puerto Rico, Puerto Rico) for inputs relating to analysis of Earth's atmosphere; J. R. Lobry (University of Lyons, France) who helped with use of the cardinal pH model; N. J. Tosca (University of Cambridge, England, UK) for discussions about thermodynamic properties of aqueous sulfuric acid solutions; and E. L. J. Watkin (Curtin University, Australia) who provided information about stress tolerance of Acidihalobacter. J.E.H. was funded by the Biotechnology and Biological Sciences Research Council (BBSRC, United Kingdom) project BBF003471; M.-P.Z. was supported by projects PID2019-104205GB-C21 of Ministry of Science and Innovation and MDM-2017-0737 Unidad de Excelencia 'María de Maeztu'- Centro de Astrobiología (CSIC-INTA) (Spain); and O.V.G. was supported by the Centre of Environmental Biotechnology Project (grant 810280) funded by the European Regional Development Fund (ERDF) through the Welsh Government.

A detailed analysis is presented of ground-based observations of atmospheric emissions on Mars and Venus under non-local thermodynamic equilibrium (non-LTE) conditions at high spectral resolution. Our first goal is to comprehend the difficulties behind the derivation of wind speeds from ground-based observations. A second goal is to set a framework to permit comparisons with other observations and with atmospheric models. A forward model including non-LTE radiative transfer is used to evaluate the information content within the telescopic beam, and is later convolved with the beam function and a typical wind field to discern the major contributions to the measured radiance, including limb and nadir views. The emission mostly arises from the non-LTE limb around altitudes of 75 km on Mars and 110 km on Venus. We propose a parameterization of the limb emission using few geophysical parameters which can be extended to other hypothetical CO2 planetary atmospheres. The tropospheric or LTE component of the emission varies with the temperature and is important at low solar illumination but only for the emerging radiance, not for the wind determinations since these are derived from the Doppler shift at the non-LTE line cores. We evaluated the sources of uncertainty and found that the forward model errors amount to approximately 12% of the measured winds, which is normally smaller than the instrumental errors. We applied this study to revise a set of measurements extending for three Martian years and confirmed previous results suggesting winds that are too large simulated by current Martian circulation models at equatorial latitudes during solstice. We encourage new observational campaigns, particularly for the strong jet at mid-high latitudes on Mars, and propose general guidelines and recommendations for future observations. © 2016. The American Astronomical Society. All rights reserved. ; M.A.L.-V. was supported by the Spanish MINECO through the CONSOLIDER program ASTROMOL CSD2009-00038 and through the Spanish National Plan project AYA2011-30613-CO2-1. M.A.L.-V. also acknowledges support through the ESA project 4000106548/12/NL/AF devoted to maintenance of the Mars Climate Database and through the project UPWARDS-633127 under the European Union's Horizon 2020 Programme (H2020-Compet-08-2014). L.M. acknowledges support by the German Research Foundation (DFG), Grant to Support the Initiation of International Collaboration SO 879/2-1. ; Peer reviewed

The results of a comparative analysis of various characteristics of the temperature conditions of the planetary
atmospheres in the Solar system and their dependence on orbital parameters, in particular on the length
and angular frequency of the annual cycle, are presented. In particular, the root dependence on the angular
frequency of the was noted. The dependence of the planetary equilibrium temperature in the cubic root form
of the angular frequency of the annual cycle is associated withKepler's third law. For Venus, Earth, Mars,
Jupiter, Saturn, the root dependence of the scale height and tropospheric height on the length of the annual
cycle is manifested, and the atmospheric features of the planets most distant from the Sun — Uranus and
Neptune — are noted.

A publisher correction to this article was published on 17 April 2019 ; The detection of methane on Mars has been interpreted as indicating that geochemical or biotic activities could persist on Mars today1. A number of different measurements of methane show evidence of transient, locally elevated methane concentrations and seasonal variations in background methane concentrations2–5. These measurements, however, are difficult to reconcile with our current understanding of the chemistry and physics of the Martian atmosphere6,7, which—given methane's lifetime of several centuries—predicts an even, well mixed distribution of methane1,6,8. Here we report highly sensitive measurements of the atmosphere of Mars in an attempt to detect methane, using the ACS and NOMAD instruments onboard the ESA-Roscosmos ExoMars Trace Gas Orbiter from April to August 2018. We did not detect any methane over a range of latitudes in both hemispheres, obtaining an upper limit for methane of about 0.05 parts per billion by volume, which is 10 to 100 times lower than previously reported positive detections2,4. We suggest that reconciliation between the present findings and the background methane concentrations found in the Gale crater4 would require an unknown process that can rapidly remove or sequester methane from the lower atmosphere before it spreads globally. © 2019, The Author(s), under exclusive licence to Springer Nature Limited. ; ExoMars is the space mission of ESA and Roscosmos. The ACS experiment is led by IKI, the Space Research Institute in Moscow, assisted by LATMOS in France. The project acknowledges funding by Roscosmos and CNES. The science operations of ACS are funded by Roscosmos and ESA. IKI affiliates acknowledge funding under grant number 14.W03.31.0017 and contract number 0120.0 602993 (0028-2014-0004) of the Russian government. The NOMAD experiment is led by the Royal Belgian Institute for Space Aeronomy (BIRA-IASB), assisted by co-PI teams from Spain (IAA-CSIC), Italy (INAF-IAPS), and the UK (Open University). This project acknowledges funding by the Belgian Science Policy Office (BELSPO), with the financial and contractual coordination of the ESA Prodex Office (PEA 4000103401 and PEA 4000121493), by Spanish MICINN through its Plan Nacional and by European funds under grants ESP2015-65064-C2-1-P and ESP2017-87143-R (MINECO/FEDER), as well as by the UK Space Agency through grants ST/R005761/1, ST/P001262/1, ST/R001405/1, ST/S00145X/1, ST/R001367/1, ST/P001572/1 and ST/R001502/1, and the Italian Space Agency through grant 2018-2-HH.0. This work was supported by the Belgian Fonds de la Recherche Scientifique-FNRS under grant number 30442502 (ET_HOME). ; Peer Reviewed

This study reports in-situ sedimentologic evidence of giant floods in Gale crater, Mars, during the Noachian Period. Features indicative of floods are a series of symmetrical, 10 m-high gravel ridges that occur in the Hummocky Plains Unit (HPU). Their regular spacing, internal sedimentary structures, and bedload transport of fragments as large as 20 cm suggest that these ridges are antidunes: a type of sedimentary structure that forms under very strong flows. Their 150 m wavelength indicates that the north-flowing water that deposited them was at least 24 m deep and had a minimum velocity of 10 m/s. Floods waned rapidly, eroding antidune crests, and re-deposited removed sediments as patches on the up-flow limbs and trough areas between these ridges forming the Striated Unit (SU). Each patch of the SU is 50–200 m wide and long and consists of 5–10 m of south-dipping layers. The strike and dip of the SU layers mimic the attitude of the flank of the antidune on which they were deposited. The most likely mechanism that generated flood waters of this magnitude on a planet whose present-day average temperature is − 60 °C was the sudden heat produced by a large impact. The event vaporized frozen reservoirs of water and injected large amounts of CO and CH from their solid phases into the atmosphere. It temporarily interrupted a cold and dry climate and generated a warm and wet period. Torrential rainfall occurred planetwide some of which entered Gale crater and combined with water roaring down from Mt. Sharp to cause gigantic flash floods that deposited the SU and the HPU on Aeolis Palus. The warm and wet climate persisted even after the flooding ended, but its duration cannot be determined by our study. ; With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

Intro -- Biogeochemistry: An Analysis of Global Change -- Copyright -- Dedication -- Contents -- Preface -- Acknowledgments -- Part I: Processes and reactions -- Chapter 1: Introduction -- What is biogeochemistry? -- Understanding the earth as a chemical system -- Perturbations of the steady-state -- Large-scale experiments -- Scales of endeavor -- Thermodynamics -- Stoichiometry -- Lovelock's Gaia -- Chapter 2: Origins -- Introduction -- Origins of the elements -- Origin of the solar system and the solid earth -- Origin of the atmosphere and the oceans -- Origin of life -- Evolution of metabolic pathways -- Photosynthesis: The origin of oxygen on earth -- Chemoautotrophy -- Anaerobic respiration in an aerobic world -- Comparative planetary history: Earth, Mars, and Venus -- Mars -- Venus -- Moons and exoplanets -- Summary -- Chapter 3: The Atmosphere -- Introduction -- Structure and circulation -- Atmospheric composition -- Gases -- Aerosols -- Biogeochemical reactions in the troposphere -- Major constituents-Nitrogen -- Oxygen -- Carbon dioxide -- Trace biogenic gases -- Oxidation reactions in the atmosphere -- Atmospheric deposition -- Processes -- Regional patterns and trends -- Biogeochemical reactions in the stratosphere -- Ozone -- Stratospheric sulfur compounds -- Models of the atmosphere and global climate -- Summary -- Chapter 4: The Lithosphere -- Introduction -- Rock weathering -- Chemical weathering -- Secondary minerals -- Soil chemical reactions -- Cation exchange capacity -- Soil buffering -- Anion adsorption capacity -- Phosphorus minerals -- Soil development -- Forests -- Grasslands -- Deserts -- Models of soil development -- Weathering rates -- Chemical weathering rates -- Mechanical weathering -- Total denudation rates -- Summary -- Chapter 5: The Carbon Cycle of Terrestrial Ecosystems -- Introduction -- Photosynthesis.