DOCSLIB.ORG

The Case for a Wet, Warm Climate on Early Mars. Pollack, J.B

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Case for a Wet, Warm Climate on Early Mars. Pollack, J.B ICARUS 71, 203-224 (1987) The Case for a Wet, Warm Climate on Early Mars J. B. POLLACK AND J. F. KASTING NASA Ames Research Center, Moffett Field, California 94035 S. M. RICHARDSON Iowa State University, Ames, Iowa 50011 AND K. POLIAKOFF I.M.I. Inc., San Jose, California 95114 Received September 22, 1986; revised March 9, 1987 Theoretical arguments are presented in support of the idea that Mars possessed a dense CO2 atmosphere and a wet, warm climate early in its history. Calculations with a one-dimensional radiative-convective climate model indicate that CO2 pressures between 1 and 5 bars would have been required to keep the surface temperature above the freezing point of water early in the planet's history. The higher value corresponds to globally and orbitally averaged conditions and a 30% reduction in solar luminosity; the lower value corresponds to conditions at the equator during perihelion at times of high orbital eccentricity and the same reduced solar luminosity. The plausibility of such a COz greenhouse is tested by formulating a simple model of the CO2 geochemical cycle on early Mars. By appropriately scaling the rate of silicate weathering on present Earth, we estimate a weathering time constant of the order of several times 107 years for early Mars. Thus, a dense atmosphere could have persisted for a geologically significant time period (-109 years) only if atmospheric COz was being continuously resupplied. The most likely mechanism by which this might have been accomplished is the thermal decomposition of carbonate rocks induced directly and indirectly (through burial) by intense, global-scale volcanism. For plausible values of the early heat flux, the recycling time constant is also of the order of several times 107 years. The amount of COz dissolved in standing bodies of water was probably small; thus, the total surficiai CO2 inventory required to maintain these conditions was approximately 2 to 10 bars. The amount of CO2 in Mars' atmosphere would eventually have dwindled, and the climate cooled, as the planet's internal heat engine ran down. A test for this theory will be provided by spectroscopic searches for carbonates in Mars' crust. © 1987 Academic Press, Inc. 1. INTRODUCTION surface above the temperature at which the planet radiates to space, about 212°K (Pol- Today, Mars is a desert world. The glo- lack 1979). Although temperatures at the bally averaged atmospheric pressure at the surface rise above the freezing point of surface is only about 7 mbar. Hence, the water near the equator during the warmest dominant carbon dioxide atmosphere pro- part of the day, water ice is evaporated so duces only about a 5°K warming of the efficiently that its temperature at the sur- 203 0019-1035/87 $3.00 Copyright © 1987 by Academic Press, Inc. All rights of reproduction in any form reserved. 204 POLLACK ET AL. face, except perhaps for some very special widespread volcanism or greenhouse circumstances, cannot reach 273°K (Inger- warming within an exposed ice deposit soll 1970). (Cloy 1984). However, the climate of Mars may not Geomorphic studies of large impact have always been as severe as it is today. basins on Mars indicate that such features Geomorphic evidence and theoretical and their associated secondary craters and arguments suggest that the atmosphere of ejecta were much more heavily eroded in Mars may have been significantly denser the planet's early history--more specifi- early in the planet's history (Walker 1978, cally, prior to the formation of the Argyre Pollack 1979, Pollack and Yung 1980, Cess basin--than at later times (Schultz 1985). If et al. 1980, Toon et al. 1980, Kahn 1985, this interpretation is correct, it implies the Schultz 1985). The resulting greenhouse existence of a much denser atmosphere at warming may have been much larger than these early times. Furthermore, there that at present, perhaps large enough to appears to have been a dramatic decrease permit the common occurrence of liquid in the density of valley networks and a water at the surface (Pollack 1979). This change in drainage style after the Argyre possibility was first indicated by the impact (Schultz 1985). These correlations discovery of fluvially produced channels on are consistent with the existence of a dense images obtained by the Mariner 9 orbiting atmosphere in Mars' early history, one spacecraft (Masursky 1973). However, it capable of raising the surface temperature was soon realized that the large outflow above the freezing point of water for an channels might be generated under current extended period of time (-109 years). climate conditions. Large amounts of liquid The most promising gas for creating a water, rapidly released from a near-surface large greenhouse effect on early Mars is reservoir, could flow large distances before carbon dioxide. It is likely that much more totally freezing by forming a top, insulating of it was released into the atmosphere over layer of ice (Peale et al. 1975, Baker 1978). the planet's historywespecially at early This mechanism may be appropriate to times--than resides there today. Further- explain isolated, local channels, but it is more, carbon dioxide is relatively stable harder to make such an argument for the against UV photolysis (Pollack 1979, Pol- fluvial gullies or valley networks. Such fea- lack and Yung 1980, Cess et al. 1980). tures are ubiquitous on the old terrain of the Alternative greenhouse gases, such as southern highlands. Some corresponding ammonia, methane, and sulfur dioxide, are widespread process is needed to generate rapidly photolyzed into gases and/or par- the liquid water that produced them. ticles that either are poor greenhouse gases Careful analyses of Mariner 9 and Viking (e.g., nitrogen) or have short residence images of valley networks indicate that times in the atmosphere (e.g., sulfuric acid they were formed chiefly by sapping, rather aerosols) (Pollack and Yung 1980, Cess et than by rainfall (Sharp and Malin 1975, al. 1980). Greenhouse calculations indicate Pieri 1980). This deduction does not pro- that CO2 partial pressures in excess of vide hard evidence that Mars was warmer about 1 bar are required to raise the surface in its early history. On the other hand, there temperature on Mars above the freezing is still a requirement that thermal condi- point of water (Pollack 1979, Cess et al. tions close to the surface permitted the 1980, Toon et al. 1980). Such quantities of occurrence of liquid water over some finite carbon dioxide are consistent with interval of time at many locations in the old estimates of the planet's total CO2 cratered terrain. A warm climate would inventory, as discussed in Section 6 of this represent one such mechanism (Pollack paper. 1979). Alternative possibilities include For the time being, we assume that A WARM AND WET MARS 205 enough carbon dioxide was present in the decomposed by processes associated with early atmosphere of Mars to raise the sur- global-scale volcanism on time scales com- face temperature above the freezing point parable to the weathering time scales. This of water, at least at low latitudes. We first decomposition returns gaseous CO2 to perform greenhouse calculations with the atmosphere. Hence, dense CO2 improved opacities for carbon dioxide and atmospheres can be maintained on early water vapor to define more precisely the Mars with plausible volatile inventories. amount of carbon dioxide needed to main- However, at later times, recycling car- tain these conditions. Then, we consider bonate rocks becomes inefficient and so the stability of this dense carbon dioxide liquid water occurs on the surface far less atmosphere against the formation of car- frequently. bonate rocks via the weathering of silicate rocks. On Earth, in the presence of liquid water, chemical weathering proceeds at 2. GREENHOUSE MODELS such a rate that all the atmospheric carbon In this section of the paper, we present dioxide would be eliminated on a time scale estimates of the amount of atmospheric of I0,000 years in the absence of CO2 sour- carbon dioxide needed to raise the surface ces (e.g., volcanic outgassing) (Holland temperature on early Mars above the freez- 1978). We use what is known about the CO2 ing point of water. The greenhouse warm- geochemical cycle on Earth to estimate the ing is produced by the infrared opacity of time scale for CO2 loss on Mars. Next, we both gaseous carbon dioxide and water evaluate the time scale on which the vapor. However, the amount of atmo- atmosphere can be resupplied with gas by spheric water vapor is controlled by juvenile outgassing and volcanically driven its vapor pressure curve, as is the case for recycling of carbonate rocks. Finally, we the present atmosphere of the Earth. determine the total volatile inventory of near-surface carbon dioxide required to 2.1. Procedure maintain a dense carbon dioxide atmo- A one-dimensional radiative-convective sphere over a billion years by a quasi- model was used to determine the steady- steady-state carbon dioxide cycle that state vertical temperature profile in the involves a balance between production and atmosphere and the temperature at the sur- loss. Through such analyses we hope to face. Details of the model have been understand better the plausibility of a published elsewhere (Kasting and Acker- warm, wet climate on Mars in its early man 1986) and will not be repeated here. history. In the final sections of the paper we We assume that the lapse rate in the make such an assessment and propose a troposphere follows a moist adiabat and possible observational test of our scenario. that the tropospheric relative humidity It is perhaps useful to summarize here decreases linearly with pressure, starting the major theses of this paper as a guide to from a value of 0.77 at the surface (Manabe the following sections.
Load more

Recommended publications
  • Appendix a Recovery of Ejecta Material from Confirmed, Probable
    Appendix A Recovery of Ejecta Material from Confirmed, Probable, or Possible Distal Ejecta Layers A.1 Introduction In this appendix we discuss the methods that we have used to recover and study ejecta found in various types of sediment and rock. The processes used to recover ejecta material vary with the degree of lithification. We thus discuss sample processing for unconsolidated, semiconsolidated, and consolidated material separately. The type of sediment or rock is also important as, for example, carbonate sediment or rock is processed differently from siliciclastic sediment or rock. The methods used to take and process samples will also vary according to the objectives of the study and the background of the investigator. We summarize below the methods that we have found useful in our studies of distal impact ejecta layers for those who are just beginning such studies. One of the authors (BPG) was trained as a marine geologist and the other (BMS) as a hard rock geologist. Our approaches to processing and studying impact ejecta differ accordingly. The methods used to recover ejecta from unconsolidated sediments have been successfully employed by BPG for more than 40 years. A.2 Taking and Handling Samples A.2.1 Introduction The size, number, and type of samples will depend on the objective of the study and nature of the sediment/rock, but there a few guidelines that should be followed regardless of the objective or rock type. All outcrops, especially those near industrialized areas or transportation routes (e.g., highways, train tracks) need to be cleaned off (i.e., the surface layer removed) prior to sampling.
    [Show full text]
  • Liquid Water on Mars
    Report, Planetary Sciences Unit (AST80015), Swinburne Astronomy Online Preprint typeset using LATEX style emulateapj v. 12/16/11 LIQUID WATER ON MARS M. Usatov1 Report, Planetary Sciences Unit (AST80015), Swinburne Astronomy Online ABSTRACT Geomorphological, mineralogical and other evidence of the conditions favoring the existence of water on Mars in liquid phase is reviewed. This includes signatures of past and, possibly, present aqueous environments, such as the northern ocean, lacustrine environments, sedimentary and thermokarst landforms, glacial activity and water erosion features. Reviewed also are hydrous weathering processes, observed on surface remotely and also via analysis of Martian meteorites. Chemistry of Martian water is discussed: the triple point, salts and brines, as well as undercooled liquid interfacial and solid-state greenhouse effect melted waters that may still be present on Mars. Current understanding of the evolution of Martian hydrosphere over geological timescales is presented from early period to the present time, along with the discussion of alternative interpretations and possibilities of dry and wet Mars extremes. 1. INTRODUCTION morphological and mineralogical evidence of aqueous en- The presence of water on Earth, as seen from space, vironments available in the past and, possibly, present can be implied from the observations of low-albedo fea- time is presented in x3 which will be correlated with the tures, like seas and oceans, fluvial features on its sur- current understanding of the evolution of Martian hy- face, atmospheric phenomena, polar ice caps, and the drosphere at x4. Alternative (dry) interpretations of the snow cover exhibiting seasonal variations, not to mention evidence are discussed in x5. spectroscopy.
    [Show full text]
  • Peter Weiss. Andrei Platonov. Ragnvald Blix. Georg Henrik Von Wright. Adam Michnik
    A quarterly scholarly journal and news magazine. March 2011. Vol IV:1 From the Centre for Baltic and East European Studies (CBEES) Södertörn University, Stockholm FEATURE. Steklov – Russian BALTIC temple of pure thought W O Rbalticworlds.com L D S COPING WITH TRANSITIONS PETER WEISS. ANDREI PLATONOV. RAGNVALD BLIX. GEORG HENRIK VON WRIGHT. ADAM MICHNIK. SLAVENKA DRAKULIĆ. Sixty pages BETRAYED GDR REVOLUTION? / EVERYDAY BELARUS / WAVE OF RELIGION IN ALBANIA / RUSSIAN FINANCIAL MARKETS 2short takes Memory and manipulation. Transliteration. Is anyone’s suffering more important than anyone else’s? Art and science – and then some “IF YOU WANT TO START a war, call me. Transliteration is both art and science CH I know all about how it's done”, says – and, in many cases, politics. Whether MÄ author Slavenka Drakulić with a touch царь should be written as tsar, tzar, ANNA of gallows humor during “Memory and czar, or csar may not be a particu- : H Manipulation: Religion as Politics in the larly sensitive political matter today, HOTO Balkans”, a symposium held in Lund, but the question of the transliteration P Sweden, on December 2, 2010. of the name of the current president This issue of the journal includes a of Belarus is exceedingly delicate. contribution from Drakulić (pp. 55–57) First, and perhaps most important: in which she claims that top-down gov- which name? Both the Belarusian ernance, which started the war, is also Аляксандр Лукашэнка, and the Rus- the path to reconciliation in the region. sian Александр Лукашенко are in use. Balkan experts attending the sympo- (And, while we’re at it, should that be sium agree that the war was directed Belarusian, or Belarussian, or Belaru- from the top, and that “top-down” is san, or Byelorussian, or Belorussian?) the key to understanding how the war BW does not want to take a stand on began in the region.
    [Show full text]
  • The Mars Global Surveyor Mars Orbiter Camera: Interplanetary Cruise Through Primary Mission
    p. 1 The Mars Global Surveyor Mars Orbiter Camera: Interplanetary Cruise through Primary Mission Michael C. Malin and Kenneth S. Edgett Malin Space Science Systems P.O. Box 910148 San Diego CA 92130-0148 (note to JGR: please do not publish e-mail addresses) ABSTRACT More than three years of high resolution (1.5 to 20 m/pixel) photographic observations of the surface of Mars have dramatically changed our view of that planet. Among the most important observations and interpretations derived therefrom are that much of Mars, at least to depths of several kilometers, is layered; that substantial portions of the planet have experienced burial and subsequent exhumation; that layered and massive units, many kilometers thick, appear to reflect an ancient period of large- scale erosion and deposition within what are now the ancient heavily cratered regions of Mars; and that processes previously unsuspected, including gully-forming fluid action and burial and exhumation of large tracts of land, have operated within near- contemporary times. These and many other attributes of the planet argue for a complex geology and complicated history. INTRODUCTION Successive improvements in image quality or resolution are often accompanied by new and important insights into planetary geology that would not otherwise be attained. From the variety of landforms and processes observed from previous missions to the planet Mars, it has long been anticipated that understanding of Mars would greatly benefit from increases in image spatial resolution. p. 2 The Mars Observer Camera (MOC) was initially selected for flight aboard the Mars Observer (MO) spacecraft [Malin et al., 1991, 1992].
    [Show full text]
  • Did Mars Possess a Dense Atmosphere During the First ~400 Million Years?
    Did Mars possess a dense atmosphere during the first ~400 million years? M. Scherf1, H. Lammer1 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria ([email protected], [email protected]); This is a preprint of an article published in Space Science Reviews. The final authenticated version can be found online at: https://doi.org/10.1007/s11214- 020-00779-3 Abstract It is not yet entirely clear whether Mars began as a warm and wet planet that evolved towards the present-day cold and dry body or if it always was cold and dry with just some sporadic episodes of liquid water on its surface. An important clue into this question can be gained by studying the earliest evolution of the Mar- tian atmosphere and whether it was dense and stable to maintain a warm and wet climate or tenuous and susceptible to strong atmospheric escape. In this review we therefore discuss relevant aspects for the evolution and stability of a potential early Martian atmosphere. This contains the EUV flux evolution of the young Sun, the formation timescale and volatile inventory of the planet including volcanic degas- sing, impact delivery and removal, the loss of the catastrophically outgassed steam atmosphere, atmosphere-surface interactions, as well as thermal and non-thermal escape processes affecting a potential secondary atmosphere at early Mars. While early non-thermal escape at Mars before 4 billion years ago is poorly understood, in particular in view of its ancient intrinsic magnetic field, research on thermal es- cape processes and the stability of a CO2-dominated atmosphere around Mars against high EUV fluxes indicate that volatile delivery and volcanic degassing can- not counterbalance the strong thermal escape.
    [Show full text]
  • The Medusae Fossae Formation As the Single Largest Source of Dust on Mars
    ARTICLE DOI: 10.1038/s41467-018-05291-5 OPEN The Medusae Fossae Formation as the single largest source of dust on Mars Lujendra Ojha1, Kevin Lewis1, Suniti Karunatillake 2 & Mariek Schmidt3 Transport of fine-grained dust is one of the most widespread sedimentary processes occurring on Mars today. In the present climate, eolian abrasion and deflation of rocks are likely the most pervasive and active dust-forming mechanism. Martian dust is globally 1234567890():,; enriched in S and Cl and has a distinct mean S:Cl ratio. Here we identify a potential source region for Martian dust based on analysis of elemental abundance data. We show that a large sedimentary unit called the Medusae Fossae Formation (MFF) has the highest abundance of S and Cl, and provides the best chemical match to surface measurements of Martian dust. Based on volume estimates of the eroded materials from the MFF, along with the enrichment of elemental S and Cl, and overall geochemical similarity, we propose that long-term deflation of the MFF has significantly contributed to the global Martian dust reservoir. 1 Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218, USA. 2 Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, USA. 3 Department of Earth Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada. Correspondence and requests for materials should be addressed to L.O. (email: [email protected]) NATURE COMMUNICATIONS | (2018) 9:2867 | DOI: 10.1038/s41467-018-05291-5 | www.nature.com/naturecommunications 1 ARTICLE NATURE COMMUNICATIONS | DOI: 10.1038/s41467-018-05291-5 ust is ubiquitous on Mars and plays a key role in con- formation on Mars today is likely abrasion of mechanically weak temporary atmospheric and surface processes.
    [Show full text]
  • Evolution of Major Sedimentary Mounds on Mars: Build-Up Via Anticompensational Stacking Modulated by Climate Change
    Evolution of major sedimentary mounds on Mars: build-up via anticompensational stacking modulated by climate change Edwin S. Kite1,*, Jonathan Sneed1, David P. Mayer1, Kevin W. Lewis2, Timothy I. Michaels3, Alicia Hore4, Scot C.R. Rafkin5. 1. University of Chicago. 2. Johns Hopkins University. 3. SETI Institute. 4. Brock University. 5. Southwest Research Institute. (*[email protected]) Abstract. We present a new database of >300 layer-orientations from sedimentary mounds on Mars. These layer orientations, together with draped landslides, and draping of rocks over differentially- eroded paleo-domes, indicate that for the stratigraphically-uppermost ~1 km, the mounds formed by the accretion of draping strata in a mound-shape. The layer-orientation data further suggest that layers lower down in the stratigraphy also formed by the accretion of draping strata in a mound-shape. The data are consistent with terrain-influenced wind erosion, but inconsistent with tilting by flexure, differential compaction over basement, or viscoelastic rebound. We use a simple landscape evolution model to show how the erosion and deposition of mound strata can be modulated by shifts in obliquity. The model is driven by multi-Gyr calculations of Mars’ chaotic obliquity and a parameterization of terrain-influenced wind erosion that is derived from mesoscale modeling. Our results suggest that mound-spanning unconformities with kilometers of relief emerge as the result of chaotic obliquity shifts. Our results support the interpretation that Mars’ rocks record intermittent liquid-water runoff during a 108-yr interval of sedimentary rock emplacement. 1. Introduction. Understanding how sediment accumulated is central to interpreting the Earth’s geologic records (Allen & Allen 2013, Miall 2010).
    [Show full text]
  • Global Catastrophes in Earth History
    GLOBAL CATASTROPHES IN EARTH HISTORY An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality Snowbird, Utah October 20-23, 1988 N89-2 12E7 --?HEW- Sponsored by The Lunar and Planetary Institute and The National Academy of Sciences Abstracts Presented to the Topical Conference Global Catastrophes in Earth History: An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality Snowbird, Utah October 20 - 23,1988 Sponsored by Lunar and Planetary Institute and The National Academy of Sciences LPI Contribution No. 673 Compiled in 1988 Lunar and Planetary Institute Material in this volume may be copied without restraint for library, abstract service, educational, or personal research purposes; however, republication of any paper or portion thereof requires the written permission of the authors as well as appropriate acknowledgment of this publication. PREFACE This volume contains abstracts that have been accepted for presentation at the topical conference Global Catastrophes in Earth History: An Interdisciplinary Conference on Impacts, Volcanism and Mass Mortality. The Organizing Committee consisted of Robert Ginsburg, Chairman, University of Miami; Kevin Burke, Lunar and Planetary Institute; Lee M. Hunt, National Research Council; Digby McLaren, University of Ottawa; Thomas Simkin, National Museum of Natural History; Starley L. Thompson, National Center for Atmospheric Research; Karl K. Turekian, Yale University; George W. Wetherill, Carnegie Institution of Washington. Logistics and administrative support were provided by the Projects Ofice at the Lunar and Planetary Institute. This abstract volume was prepared by the Publications Office staff at the Lunar and Planetary Institute. The Lunar and Planetary Institute is operated by the Universities Space Research Association under contract No. NASW-4066 with the National Aeronautics and Space Administration.
    [Show full text]
  • Low-Albedo Surfaces and Eolian Sediment: Mars Orbiter Camera Views of Western Arabia Terra Craters and Wind Streaks
    Low-albedo surfaces and eolian sediment: Mars Orbiter Camera views of western Arabia Terra craters and wind streaks Kenneth S. Edgett Malin Space Science Systems, Inc., San Diego, California, USA Abstract. High spatial resolution (1.5 to 6 m/pixel) Mars Global Surveyor Mars Orbiter Camera images obtained September 1997 to June 2001 show that each of the large, dark wind streaks of western Arabia Terra originate at a barchan dune field on a crater floor. The streaks consist of a relatively thin (< 1 m) coating of sediment deflated from the dune fields and their vicinity. In most cases, this sediment drapes over a previous mantle that more thickly covers nearly all of western Arabia Terra. No concurrent eolian bedforms are found within the dark streaks, nor do any dunes climb up crater walls to deliver sand via saltation to the streaks. The relations between dunes, wind streak, and subjacent terrain imply that dark-toned grains finer than those that comprise the dunes are lifted into suspension and carried out of the craters to be deposited on the adjacent terrain. Previous eolian physics and thermal inertia studies suggest that, under modern Martian conditions, such grains likely include silt (3.9–62.5 !m), very fine sand (62.5–125 !m), and possibly fine sand (to ~210 !m). The streaks change in terms of extent, relative albedo, and surface pattern over periods measured in years; however, through June 2001, very little evidence for recent eolian activity (dust plumes, storms, dune movement) was observed. received 18 July 2001, revised 21 December 2001, accepted 2 January 2002, published 13 June 2002 Citation: Edgett, K.
    [Show full text]
  • Special Regions’’: Findings of the Second MEPAG Special Regions Science Analysis Group (SR-SAG2)
    ASTROBIOLOGY Volume 14, Number 11, 2014 News & Views ª Mary Ann Liebert, Inc. DOI: 10.1089/ast.2014.1227 A New Analysis of Mars ‘‘Special Regions’’: Findings of the Second MEPAG Special Regions Science Analysis Group (SR-SAG2) John D. Rummel,1 David W. Beaty,2 Melissa A. Jones,2 Corien Bakermans,3 Nadine G. Barlow,4 Penelope J. Boston,5 Vincent F. Chevrier,6 Benton C. Clark,7 Jean-Pierre P. de Vera,8 Raina V. Gough,9 John E. Hallsworth,10 James W. Head,11 Victoria J. Hipkin,12 Thomas L. Kieft,5 Alfred S. McEwen,13 Michael T. Mellon,14 Jill A. Mikucki,15 Wayne L. Nicholson,16 Christopher R. Omelon,17 Ronald Peterson,18 Eric E. Roden,19 Barbara Sherwood Lollar,20 Kenneth L. Tanaka,21 Donna Viola,13 and James J. Wray22 Abstract A committee of the Mars Exploration Program Analysis Group (MEPAG) has reviewed and updated the description of Special Regions on Mars as places where terrestrial organisms might replicate (per the COSPAR Planetary Protection Policy). This review and update was conducted by an international team (SR-SAG2) drawn from both the biological science and Mars exploration communities, focused on understanding when and where Special Regions could occur. The study applied recently available data about martian environments and about terrestrial organisms, building on a previous analysis of Mars Special Regions (2006) undertaken by a similar team. Since then, a new body of highly relevant information has been generated from the Mars Reconnaissance Orbiter (launched in 2005) and Phoenix (2007) and data from Mars Express and the twin Mars Exploration Rovers (all 2003).
    [Show full text]
  • FY 2015-2016 Annual Report
    Oregon Wild 2016 ANNUAL REPORT FOLD-OUT MAP OF OREGON’S PUBLIC LANDS INSIDE n fscal year 2015-2016 Oregon Wild entered the fnal year of our four-year strategic plan. IAlong the way we have achieved numerous successes and have a lot to be proud of in defending and protecting Oregon’s special places. As 2016 got underway, a team of Oregon Wild board and staf took on the task of developing our new plan. After dozens of conversations, a deep dive analysis on our theory of change, and feedback from the entire team, we fnalized a new four-year plan after the November election. We are excited to have delineated aspirational long term goals alongside concrete objectives for the coming four years. We know that our work to protect our wildlands, wildlife, and waters for future generations is as important as it has ever been. We also realize that we face daunting challenges ahead and must adapt our approach to respond to the threats we are sure to face. We are fortunate to be in a strong fnancial position, with revenue topping one million dollars for the third straight year. With this fnancial stability and a solid reserve, we have expanded our staf to deepen our impact. Our work to protect wilderness, safeguard native species like wolves, and conserve the last of our ancient forests is resonating with the public. Te past two fscal years have seen the largest increases in new Oregon Wild members in over a decade and we expect that trend to continue. While many of our eforts are built for the long haul, we made marked progress in several campaigns and celebrated clear victories in other eforts over the past year.
    [Show full text]
  • A New Martian Radiative Transfer Model: Applications Using in Situ Measurements
    UNIVERSIDAD COMPLUTENSE DE MADRID FACULTAD DE CIENCIAS FÍSICAS Departamento de Física de la Tierra, Astronomía y Astrofísica II TESIS DOCTORAL A new martian radiative transfer model: applications using in situ measurements Un nuevo modelo de transferencia radiativa en Marte: aplicaciones utilizando medidas in situ MEMORIA PARA OPTAR AL GRADO DE DOCTOR PRESENTADA POR Álvaro Vicente-Retortillo Rubalcaba Directores Francisco Valero Rodríguez Luis Vázquez Martínez Germán Martínez Martínez Madrid, 2017 © Álvaro Vicente-Retortillo Rubalcaba, 2017 UNIVERSIDAD COMPLUTENSE DE MADRID FACULTAD DE CIENCIAS FÍSICAS Departamento de Física de la Tierra, Astronomía y Astrofísica II TESIS DOCTORAL A NEW MARTIAN RADIATIVE TRANSFER MODEL: APPLICATIONS USING IN SITU MEASUREMENTS UN NUEVO MODELO DE TRANSFERENCIA RADIATIVA EN MARTE: APLICACIONES UTILIZANDO MEDIDAS IN SITU Memoria para optar al grado de doctor con Mención Internacional Presentada por: Álvaro de Vicente-Retortillo Rubalcaba Directores de tesis: Prof. Francisco Valero Rodríguez1 Prof. Luis Vázquez Martínez1 Dr. Germán Martínez Martínez2 1Universidad Complutense de Madrid 2University of Michigan Madrid, 2017 ii A NEW MARTIAN RADIATIVE TRANSFER MODEL: APPLICATIONS USING IN SITU MEASUREMENTS UN NUEVO MODELO DE TRANSFERENCIA RADIATIVA EN MARTE: APLICACIONES UTILIZANDO MEDIDAS IN SITU PhD. Thesis Author: Álvaro de Vicente-Retortillo Rubalcaba Advisors: Prof. Francisco Valero Rodríguez1 Prof. Luis Vázquez Martínez1 Dr. Germán Martínez Martínez2 1Universidad Complutense de Madrid 2University of Michigan Madrid, 2017 iii iv La presente Tesis Doctoral se ha realizado gracias a la concesión por parte del Ministerio de Economía y Competitividad (MINECO) de la ayuda predoctoral de Formación de Personal Investigador (FPI) con referencia BES-2012-059241, asociada al proyecto “Participación Científica en la Misión a Marte MEIGA-METNET-PRECURSOR” (AYA2011-29967-C05-02).
    [Show full text]