DOCSLIB.ORG

Comparisons of Ground-Based Tropospheric NO2 MAX-DOAS Measurements to Satellite Observations with the Aid of an Air Quality Model Over the Thessaloniki Area, Greece

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Comparisons of Ground-Based Tropospheric NO2 MAX-DOAS Measurements to Satellite Observations with the Aid of an Air Quality Model Over the Thessaloniki Area, Greece Atmos. Chem. Phys., 17, 5829–5849, 2017 www.atmos-chem-phys.net/17/5829/2017/ doi:10.5194/acp-17-5829-2017 © Author(s) 2017. CC Attribution 3.0 License. Comparisons of ground-based tropospheric NO2 MAX-DOAS measurements to satellite observations with the aid of an air quality model over the Thessaloniki area, Greece Theano Drosoglou1, Alkiviadis F. Bais1, Irene Zyrichidou1, Natalia Kouremeti1,2, Anastasia Poupkou1, Natalia Liora1, Christos Giannaros1, Maria Elissavet Koukouli1, Dimitris Balis1, and Dimitrios Melas1 1Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece 2Physikalisch-Meteorologisches Observatorium Davos, Dorfstrasse 33, 7260 Davos Dorf, Switzerland Correspondence to: Theano Drosoglou ([email protected]) Received: 11 July 2016 – Discussion started: 5 September 2016 Revised: 6 April 2017 – Accepted: 8 April 2017 – Published: 11 May 2017 Abstract. One of the main issues arising from the com- times and NO2 retrieval algorithms of the satellites. OMI parison of ground-based and satellite measurements is the data were adjusted using factors calculated by an air quality difference in spatial representativeness, which for locations modeling tool, consisting of the Weather Research and with inhomogeneous spatial distribution of pollutants may Forecasting (WRF) mesoscale meteorological model and the lead to significant differences between the two data sets. In Comprehensive Air Quality Model with Extensions (CAMx) order to investigate the spatial variability of tropospheric multiscale photochemical transport model. This approach NO2 within a sub-satellite pixel, a campaign which lasted for resulted in significant improvement of the comparisons over about 6 months was held in the greater area of Thessaloniki, the urban monitoring site. The average difference of OMI Greece. Three multi-axial differential optical absorption observations from MAX-DOAS measurements was reduced spectroscopy (MAX-DOAS) systems performed mea- to −1.68 ± 5.01 × 1015 molecules cm−2. surements of tropospheric NO2 columns at different sites representative of urban, suburban and rural conditions. The direct comparison of these ground-based measurements with corresponding products from the Ozone Monitoring Instru- 1 Introduction ment onboard NASA’s Aura satellite (OMI/Aura) showed good agreement over the rural and suburban areas, while the Nitrogen oxides (NOx D NO C NO2) are among the most im- comparison with the Global Ozone Monitoring Experiment- portant trace components of the atmosphere playing a key 2 (GOME-2) onboard EUMETSAT’s Meteorological Oper- role in the tropospheric photochemistry (e.g., Seinfeld and ational satellites’ (MetOp-A and MetOp-B) observations is Pandis, 1998). They affect the oxidation capacity and the ra- good only over the rural area. GOME-2A and GOME-2B diative forcing in the lower atmospheric layers by control- sensors show an average underestimation of tropospheric ling the ozone formation, contributing to nitric acid (HNO3) 15 NO2 over the urban area of about 10.51 ± 8.32 × 10 and nitrate radical formation and affecting the hydroxyl lev- and 10.21 ± 8.87 × 1015 molecules cm−2, respec- els (Solomon et al., 1999; Finlayson-Pitts and Pitts, 1999). tively. The mean difference between ground- The main emission sources of nitrogen oxides are fossil-fuel based and OMI observations is significantly lower combustion, biomass burning, microbiological processes in (6.60 ± 5.71 × 1015 molecules cm−2). The differences the soil, lightning and aircrafts (Lee et al., 1997; Jaeglé et found in the comparisons of MAX-DOAS data with the al., 2005). The most important anthropogenic source are the different satellite sensors can be attributed to the higher high-temperature combustion processes occurring in vehicle spatial resolution of OMI, as well as the different overpass engines and industrial and power plants (EEA, 2013). Hence, urban areas, with heavy road traffic, as well as industrial ar- Published by Copernicus Publications on behalf of the European Geosciences Union. 5830 T. Drosoglou et al.: Comparisons of ground-based tropospheric NO2 MAX-DOAS measurements eas are characterized by inhomogeneous spatial and temporal et al., 2008; Chen et al., 2009; Herman et al., 2009; Irie et patterns in NOx concentrations. al., 2012; Li et al., 2013; Ma et al., 2013; Hendrick et al., Nitrogen dioxide (NO2) is mainly produced by the oxi- 2014). Several studies have shown that satellite sensors un- dation of nitrogen monoxide (NO) and only a small propor- derestimate the tropospheric NO2 levels over regions charac- tion of NOx is emitted directly as NO2 (Hewitt and Jackson, terized by inhomogeneous pollution loadings such as urban 2009). However, in the case of diesel vehicles, the fraction and industrial locations, which is known also as the gradient of directly emitted NO2 to the total NOx emissions is much smoothing effect (Chen et al., 2009; Ma et al., 2013). Irie et higher, resulting in a significant increase of NO2 emissions al. (2012) have shown a clear bias of less than 10 % between and more frequent breaching of NO2 air quality limits in ur- space-borne and ground-based observations over the Tokyo ban locations in recent years (Grice et al., 2009; Keuken et area in Japan, which is characterized by significant spatial al., 2012). variations in NO2 concentrations. In Celarier et al. (2008), Thessaloniki is the second largest city of Greece and, with the correlation coefficient of the comparison of OMI-derived a population of more than 1 million inhabitants, hosts about tropospheric NO2 with different multi-axial (MAX)-DOAS 10 % of the total population of the country (Resident Popula- instruments in Cabauw, the Netherlands, were found to be tion Census, 2011). The main air pollution sources in Thes- about ∼ 0.6. Kramer et al. (2008) estimated similar correla- saloniki are road transport, domestic heating and industrial tion coefficients between OMI and concurrent MAX-DOAS facilities, while the air quality of the city is affected by the observations over Leicester, UK, while they found significant local topographic and meteorological characteristics and re- underestimation of OMI in late autumn and winter months gional pollution transport (Poupkou et al., 2011). NO2 con- when comparing with weighted near-surface concentrations. centrations in the city have tended to stabilize during the last Ma et al. (2013) have shown a systematic underestimation of decades with the highest NO2 levels observed at the traf- about 26–38 % in tropospheric NO2 over Beijing by OMI, fic hotspots in the center of the city (Moussiopoulos et al., depending on the satellite retrieval algorithm and time pe- 2008). According to Zyrichidou et al. (2009), the mean value riod. of tropospheric NO2 column until 2008 over Thessaloniki In this study, tropospheric NO2 column measurements was 3.9 ± 3.8 × 1015 and 4.2 ± 3.8 × 1015 molecules cm−2, derived from satellite sensors (OMI/Aura, hereafter OMI; as observed by the Global Ozone Monitoring Experiment-2 GOME-2/MetOp-A, hereafter GOME-2A; and GOME- (GOME-2) and Ozone Monitoring Instrument (OMI) satel- 2/MetOp-B, hereafter GOME-2B) are compared with data lite instruments, respectively. from MAX-DOAS systems that were deployed in three dif- Well-established methods are used worldwide for monitor- ferent sites within the greater area of Thessaloniki, Greece, ing NO2 concentrations based on both in situ measurements for a period of a few months. Air quality at these locations from local air quality networks and remote sensing from is representative of urban, suburban and rural conditions. In ground-based instruments and satellite sensors (e.g., Or- order to minimize the effect of smoothing of NO2 gradients dóñez et al., 2006; Blond et al., 2007; Brinksma et al., in the satellite data and improve their comparison with the 2008). Space-borne measurements provide information on ground-based data, adjustment factors (AFs) were calculated NO2 concentrations at a larger scale and over areas such as by an air quality modeling tool, consisting of Weather Re- oceans and deserts, where ground-based systems cannot be search and Forecasting (WRF) meteorological model and the easily deployed. On the other hand, the spatial and tempo- Comprehensive Air Quality Model with Extensions (CAMx), ral resolution of the satellite data are, respectively, limited by and were applied to OMI data. the satellite footprint size and its overpass time. Thus, well- established, extended and relatively dense ground-based net- works in areas where significant spatial and temporal varia- 2 Instrumentation and data tions in NO2 loading are observed can improve the validation of the satellite data sets. 2.1 The Phaethon system Remote sensing of NO2 concentrations is based mainly on the differential optical absorption spectroscopy (DOAS) Phaethon is a miniature ground-based MAX-DOAS system analysis (Platt, 1994; Platt and Stutz, 2008) of radiance data, that performs fast, spectrally resolved measurements in the measured either from space or from the ground. The first wavelength range of 300–450 nm which are used for the re- studies applying the DOAS method to zenith ground-based trieval of total and tropospheric columns of atmospheric trace measurements for the retrieval of tropospheric and strato- gases. The prototype system (Phaethon #1) was developed spheric NO2 date back to the 1970s (Brewer et al., 1973; in 2006 at the Laboratory of Atmospheric Physics (LAP) Noxon, 1975). In the last few decades, the DOAS analy- in Thessaloniki, Greece (Kouremeti et al., 2008, 2013). sis has been widely applied in ground-based systems for the Phaethon has been recently upgraded to improve its perfor- monitoring of air quality species like NO2 in the atmosphere mance and two new clone systems (Phaethon #2 and #3) and is considered as a reference technique for the validation have been assembled. The system comprises a cooled minia- of satellite observations (e.g., Celarier et al., 2008; Kramer ture charge-coupled device (CCD) spectrograph (AvaSpec- Atmos. Chem. Phys., 17, 5829–5849, 2017 www.atmos-chem-phys.net/17/5829/2017/ T.
Load more

Recommended publications
  • A Wunda-Full World? Carbon Dioxide Ice Deposits on Umbriel and Other Uranian Moons
    Icarus 290 (2017) 1–13 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus A Wunda-full world? Carbon dioxide ice deposits on Umbriel and other Uranian moons ∗ Michael M. Sori , Jonathan Bapst, Ali M. Bramson, Shane Byrne, Margaret E. Landis Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA a r t i c l e i n f o a b s t r a c t Article history: Carbon dioxide has been detected on the trailing hemispheres of several Uranian satellites, but the exact Received 22 June 2016 nature and distribution of the molecules remain unknown. One such satellite, Umbriel, has a prominent Revised 28 January 2017 high albedo annulus-shaped feature within the 131-km-diameter impact crater Wunda. We hypothesize Accepted 28 February 2017 that this feature is a solid deposit of CO ice. We combine thermal and ballistic transport modeling to Available online 2 March 2017 2 study the evolution of CO 2 molecules on the surface of Umbriel, a high-obliquity ( ∼98 °) body. Consid- ering processes such as sublimation and Jeans escape, we find that CO 2 ice migrates to low latitudes on geologically short (100s–1000 s of years) timescales. Crater morphology and location create a local cold trap inside Wunda, and the slopes of crater walls and a central peak explain the deposit’s annular shape. The high albedo and thermal inertia of CO 2 ice relative to regolith allows deposits 15-m-thick or greater to be stable over the age of the solar system.
    [Show full text]
  • Exomoon Habitability Constrained by Illumination and Tidal Heating
    submitted to Astrobiology: April 6, 2012 accepted by Astrobiology: September 8, 2012 published in Astrobiology: January 24, 2013 this updated draft: October 30, 2013 doi:10.1089/ast.2012.0859 Exomoon habitability constrained by illumination and tidal heating René HellerI , Rory BarnesII,III I Leibniz-Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany, [email protected] II Astronomy Department, University of Washington, Box 951580, Seattle, WA 98195, [email protected] III NASA Astrobiology Institute – Virtual Planetary Laboratory Lead Team, USA Abstract The detection of moons orbiting extrasolar planets (“exomoons”) has now become feasible. Once they are discovered in the circumstellar habitable zone, questions about their habitability will emerge. Exomoons are likely to be tidally locked to their planet and hence experience days much shorter than their orbital period around the star and have seasons, all of which works in favor of habitability. These satellites can receive more illumination per area than their host planets, as the planet reflects stellar light and emits thermal photons. On the contrary, eclipses can significantly alter local climates on exomoons by reducing stellar illumination. In addition to radiative heating, tidal heating can be very large on exomoons, possibly even large enough for sterilization. We identify combinations of physical and orbital parameters for which radiative and tidal heating are strong enough to trigger a runaway greenhouse. By analogy with the circumstellar habitable zone, these constraints define a circumplanetary “habitable edge”. We apply our model to hypothetical moons around the recently discovered exoplanet Kepler-22b and the giant planet candidate KOI211.01 and describe, for the first time, the orbits of habitable exomoons.
    [Show full text]
  • Planetary Nomenclature: an Overview and Update
    3rd Planetary Data Workshop 2017 (LPI Contrib. No. 1986) 7119.pdf PLANETARY NOMENCLATURE: AN OVERVIEW AND UPDATE. T. Gaither1, R. K. Hayward1, J. Blue1, L. Gaddis1, R. Schulz2, K. Aksnes3, G. Burba4, G. Consolmagno5, R. M. C. Lopes6, P. Masson7, W. Sheehan8, B.A. Smith9, G. Williams10, C. Wood11, 1USGS Astrogeology Science Center, Flagstaff, Ar- izona ([email protected]); 2ESA Scientific Support Office, Noordwijk, The Netherlands; 3Institute for Theoretical Astrophysics, Oslo, Norway; 4Vernadsky Institute, Moscow, Russia; 5Specola Vaticana, Vati- can City State; 6Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California; 7Uni- versite de Paris-Sud, Orsay, France; 8Lowell Observatory, Flagstaff, Arizona; 9Santa Fe, New Mexico; 10Minor Planet Center, Cambridge, Massachusetts; 11Planetary Science Institute, Tucson, Arizona. Introduction: The task of naming planetary Asteroids surface features, rings, and natural satellites is Ceres 113 managed by the International Astronomical Un- Dactyl 2 ion’s (IAU) Working Group for Planetary System Eros 41 Nomenclature (WGPSN). The members of the Gaspra 34 WGPSN and its task groups have worked since the Ida 25 early 1970s to provide a clear, unambiguous sys- Itokawa 17 tem of planetary nomenclature that represents cul- Lutetia 37 tures and countries from all regions of Earth. Mathilde 23 WGPSN members include Rita Schulz (chair) and Steins 24 9 other members representing countries around the Vesta 106 globe (see author list). In 2013, Blue et al. [1] pre- Jupiter sented an overview of planetary nomenclature, and Amalthea 4 in 2016 Hayward et al. [2] provided an update to Thebe 1 this overview. Given the extensive planetary ex- Io 224 ploration and research that has taken place since Europa 111 2013, it is time to update the community on the sta- Ganymede 195 tus of planetary nomenclature, the purpose and Callisto 153 rules, the process for submitting name requests, and the IAU approval process.
    [Show full text]
  • Constraints on the Habitability of Extrasolar Moons
    Formation, Detection, and Characterization of Extrasolar Habitable Planets Proceedings IAU Symposium No. 293, 2012 c International Astronomical Union 2014 N. Haghighipour, ed. doi:10.1017/S1743921313012738 Constraints on the Habitability of Extrasolar Moons Ren´e Heller1 and Rory Barnes2,3 1 Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam email: [email protected] 2 University of Washington, Dept. of Astronomy, Seattle, WA 98195, USA 3 Virtual Planetary Laboratory, NASA, USA email: [email protected] Abstract. Detections of massive extrasolar moons are shown feasible with the Kepler space telescope. Kepler’s findings of about 50 exoplanets in the stellar habitable zone naturally make us wonder about the habitability of their hypothetical moons. Illumination from the planet, eclipses, tidal heating, and tidal locking distinguish remote characterization of exomoons from that of exoplanets. We show how evaluation of an exomoon’s habitability is possible based on the parameters accessible by current and near-future technology. Keywords. celestial mechanics – planets and satellites: general – astrobiology – eclipses 1. Introduction The possible discovery of inhabited exoplanets has motivated considerable efforts towards estimating planetary habitability. Effects of stellar radiation (Kasting et al. 1993; Selsis et al. 2007), planetary spin (Williams & Kasting 1997; Spiegel et al. 2009), tidal evolution (Jackson et al. 2008; Barnes et al. 2009; Heller et al. 2011), and composition (Raymond et al. 2006; Bond et al. 2010) have been studied. Meanwhile, Kepler’s high precision has opened the possibility of detecting extrasolar moons (Kipping et al. 2009; Tusnski & Valio 2011) and the first dedicated searches for moons in the Kepler data are underway (Kipping et al.
    [Show full text]
  • Occultation Newsletter Volume 8, Number 4
    Volume 12, Number 1 January 2005 $5.00 North Am./$6.25 Other International Occultation Timing Association, Inc. (IOTA) In this Issue Article Page The Largest Members Of Our Solar System – 2005 . 4 Resources Page What to Send to Whom . 3 Membership and Subscription Information . 3 IOTA Publications. 3 The Offices and Officers of IOTA . .11 IOTA European Section (IOTA/ES) . .11 IOTA on the World Wide Web. Back Cover ON THE COVER: Steve Preston posted a prediction for the occultation of a 10.8-magnitude star in Orion, about 3° from Betelgeuse, by the asteroid (238) Hypatia, which had an expected diameter of 148 km. The predicted path passed over the San Francisco Bay area, and that turned out to be quite accurate, with only a small shift towards the north, enough to leave Richard Nolthenius, observing visually from the coast northwest of Santa Cruz, to have a miss. But farther north, three other observers video recorded the occultation from their homes, and they were fortuitously located to define three well- spaced chords across the asteroid to accurately measure its shape and location relative to the star, as shown in the figure. The dashed lines show the axes of the fitted ellipse, produced by Dave Herald’s WinOccult program. This demonstrates the good results that can be obtained by a few dedicated observers with a relatively faint star; a bright star and/or many observers are not always necessary to obtain solid useful observations. – David Dunham Publication Date for this issue: July 2005 Please note: The date shown on the cover is for subscription purposes only and does not reflect the actual publication date.
    [Show full text]
  • Satellite Contributions to the Quantitative Characterization of Biomass Burning for Climate Modeling
    Revised Version of Review Article for Atmospheric Research Satellite Contributions to the Quantitative Characterization of Biomass Burning for Climate Modeling Charles Ichoku, Ralph Kahn, Mian Chin Lab. for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA Corresponding Author: Dr. Charles Ichoku Climate & Radiation Branch, Code 613.2 NASA Goddard Space Flight Center Greenbelt, MD 20771, USA Phone : +1-301-614-6212 Fax : +1-301-614-6307 or +1-301-614-6420 Email : [email protected] Abstract Characterization of biomass burning from space has been the subject of an extensive body of literature published over the last few decades. Given the importance of this topic, we review how satellite observations contribute toward improving the representation of biomass burning quantitatively in climate and air-quality modeling and assessment. Satellite observations related to biomass burning may be classified into five broad categories: (i) active fire location and energy release, (ii) burned areas and burn severity, (iii) smoke plume physical disposition, (iv) aerosol distribution and particle properties, and (v) trace gas concentrations. Each of these categories involves multiple parameters used in characterizing specific aspects of the biomass-burning phenomenon. Some of the parameters are merely qualitative, whereas others are quantitative, although all are essential for improving the scientific understanding of the overall distribution (both spatial and temporal) and impacts of biomass burning. Some of the qualitative satellite datasets, such as fire locations, aerosol index, and gas estimates have fairly long-term records. They date back as far as the 1970s, following the launches of the DMSP, Landsat, NOAA, and Nimbus series of earth observation satellites.
    [Show full text]
  • Planet Definition
    Marin Erceg dipl.oec. CEO ORCA TEHNOLOGIJE http://www.orca-technologies.com Zagreb, 2006. Editor : mr.sc. Tino Jelavi ć dipl.ing. aeronautike-pilot Text review : dr.sc. Zlatko Renduli ć dipl.ing. mr.sc. Tino Jelavi ć dipl.ing. aeronautike-pilot Danijel Vukovi ć dipl.ing. zrakoplovstva Translation review : Dana Vukovi ć, prof. engl. i hrv. jez. i knjiž. Graphic and html design : mr.sc. Tino Jelavi ć dipl.ing. Publisher : JET MANGA Ltd. for space transport and services http://www.yuairwar.com/erceg.asp ISBN : 953-99838-5-1 2 Contents Introduction Defining the problem Size factor Eccentricity issue Planemos and fusors Clear explanation of our Solar system Planet definition Free floating planets Conclusion References Curriculum Vitae 3 Introduction For several thousand years humans were aware of planets. While sitting by the fire, humans were observing the sky and the stars even since prehistory. They noticed that several sparks out of thousands of stars were oddly behaving, moving around the sky across irregular paths. They were named planets. Definition of the planet at that time was simple and it could have been expressed by following sentence: Sparkling dot in the sky whose relative position to the other stars is continuously changing following unpredictable paths. During millenniums and especially upon telescope discovery, human understanding of celestial bodies became deeper and deeper. This also meant that people understood better the space and our Solar system and in this period we have accepted the following definition of the planet: Round objects orbiting Sun. Following Ceres and Asteroid Belt discoveries this definition was not suitable any longer, and as a result it was modified.
    [Show full text]
  • The Thermal and Orbital Evolution of Enceladus: Observational Constraints and Models
    The thermal and orbital evolution of Enceladus: observational constraints and models Francis Nimmo UCSC Amy C. Barr PSI Marie Behounkovˇ a´ Charles University William B. McKinnon Washington University Enceladus possesses a global subsurface ocean beneath an ice shell a few tens of km thick, and is observed to be losing heat at a rate of ∼10 GW from its south polar region. Two major puzzles are the source of the observed heat, and how the ocean could have been maintained. Tidal dissipation in Enceladus is ultimately controlled by the rate of dissipation within Saturn, parameterized by the factor Qp.A Qp of about 2,000 is indicated by astrometric measurements and generates an equilibrium heating rate at Enceladus sufficient to explain the observed heat and maintain an ocean indefinitely if the ice shell is conductive. If constant, this Qp would indicate an age for Enceladus much less than that of the solar system. An alternative, however, termed the “resonance-locking” scenario, is that the effective Qp is time-variable such that the heating rate is almost constant over geological time. This scenario can explain the long-term survival of the ocean and the present-day heat flux without requiring Enceladus to have formed recently. 1. INTRODUCTION details of how this actually works are not well understood. A particularly difficult aspect of satellite evolution is that Enceladus, despite its limited size, is one of the most their thermal and orbital evolution are often intimately cou- surprising bodies in the solar system with a south polar ter- pled. This is because the amount of tidal heating depends rain (SPT) containing localized active tectonics, remarkable on the satellite’s mechanical properties, many of which geysers connected to four prominent fracture sets (the “tiger are temperature-dependent.
    [Show full text]
  • Results from a Triple Chord Stellar Occultation and Far-Infrared Photometry of the Trans-Neptunian ?,?? Object (229762) 2007 UK126 K
    A&A 600, A12 (2017) Astronomy DOI: 10.1051/0004-6361/201628620 & c ESO 2017 Astrophysics Results from a triple chord stellar occultation and far-infrared photometry of the trans-Neptunian ?,?? object (229762) 2007 UK126 K. Schindler1; 2, J. Wolf1; 2, J. Bardecker3,???, A. Olsen3, T. Müller4, C. Kiss5, J. L. Ortiz6, F. Braga-Ribas7; 8, J. I. B. Camargo7; 9, D. Herald3, and A. Krabbe1 1 Deutsches SOFIA Institut, Universität Stuttgart, Pfaffenwaldring 29, 70569 Stuttgart, Germany e-mail: [email protected] 2 SOFIA Science Center, NASA Ames Research Center, Mail Stop N211-1, Moffett Field, CA 94035, USA 3 International Occultation Timing Association (IOTA), USA 4 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse 1, 85748 Garching, Germany 5 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege 15-17, 1121 Budapest, Hungary 6 Instituto de Astrofisica de Andalucia-CSIC, Glorieta de la Astronomia 3, 18080 Granada, Spain 7 Observatório Nacional/MCTI, Rua Gal. José Cristino 77, 20921-400 Rio de Janeiro, Brazil 8 Federal University of Technology – Paraná (UTFPR/DAFIS), Rua Sete de Setembro 3165, 80230-901 Curitiba, PR, Brazil 9 Laboratório Interinstitucional de e-Astronomia – LIneA, Rua Gal. José Cristino 77, 20921-400 Rio de Janeiro, Brazil Received 31 March 2016 / Accepted 10 October 2016 ABSTRACT Context. A stellar occultation by a trans-Neptunian object (TNO) provides an opportunity to probe the size and shape of these distant solar system bodies. In the past seven years, several occultations by TNOs have been observed, but mostly from a single location. Only very few TNOs have been sampled simultaneously from multiple locations.
    [Show full text]
  • Perfect Little Planet Educator's Guide
    Educator’s Guide Perfect Little Planet Educator’s Guide Table of Contents Vocabulary List 3 Activities for the Imagination 4 Word Search 5 Two Astronomy Games 7 A Toilet Paper Solar System Scale Model 11 The Scale of the Solar System 13 Solar System Models in Dough 15 Solar System Fact Sheet 17 2 “Perfect Little Planet” Vocabulary List Solar System Planet Asteroid Moon Comet Dwarf Planet Gas Giant "Rocky Midgets" (Terrestrial Planets) Sun Star Impact Orbit Planetary Rings Atmosphere Volcano Great Red Spot Olympus Mons Mariner Valley Acid Solar Prominence Solar Flare Ocean Earthquake Continent Plants and Animals Humans 3 Activities for the Imagination The objectives of these activities are: to learn about Earth and other planets, use language and art skills, en- courage use of libraries, and help develop creativity. The scientific accuracy of the creations may not be as im- portant as the learning, reasoning, and imagination used to construct each invention. Invent a Planet: Students may create (draw, paint, montage, build from household or classroom items, what- ever!) a planet. Does it have air? What color is its sky? Does it have ground? What is its ground made of? What is it like on this world? Invent an Alien: Students may create (draw, paint, montage, build from household items, etc.) an alien. To be fair to the alien, they should be sure to provide a way for the alien to get food (what is that food?), a way to breathe (if it needs to), ways to sense the environment, and perhaps a way to move around its planet.
    [Show full text]
  • Tectonic Deformation of Icy Surfaces: Application to Pluto and Charon
    Tectonic Deformation of Icy Surfaces: Application to Pluto and Charon. S.A. Kattenhorn, Department of Geo- logical Sciences, University of Idaho, Moscow, ID 83844-3022, [email protected]. Introduction: Spacecraft missions to the outer so- also been inferred on Enceladus [4]. Evolving tidal lar system have revealed a diverse range of icy moons, bulge heights driven by orbital recession (changing with surfaces sculpted by tectonism, cratering, mass distance to parent body) and internal differentiation wasting, thermally/compositionally driven endogenic (changing Love numbers) create explicit stress fields processes, and deposition of loose material to form that should be manifested in the deformation patterns regolith. Many icy surfaces are pervasively tectonized, [2]. Despinning will reduce flattening, providing an replete with fractures, faults, and significant topogra- additional source of stress. Tidal bulges may also mi- phy (e.g., Europa, Ganymede, Enceladus, Dione, Rhea, grate latitudinally in response to polar wander [5], pos- Titan, Miranda, Ariel, Titania, Triton). Such features sibly explaining fracture patterns on some icy moons. record a history of deformation in crosscutting rela- If tidal deformation stresses are too small to overcome tionships, with feature orientations indicating evolving the strength of the ice shell, ice shell thickening could stress conditions through time. Although extensional induce an isotropic tension [6] that augments other deformation appears to dominate, shear deformation sources of stress, helping to drive deformation. On (strike-slip faulting) and contractional deformation are Pluto and Charon, tectonic deformation could have also possible. The identification of surface deformation been driven by NSR, orbital recession, and despinning on Pluto and Charon, which have experienced stress [1]; however, all possibilities should be considered.
    [Show full text]
  • Fourier-Ray Modeling of Short-Wavelength Trapped Lee Waves Observed in Infrared Satellite Imagery Near Jan Mayen
    2830 MONTHLY WEATHER REVIEW VOLUME 134 Fourier-Ray Modeling of Short-Wavelength Trapped Lee Waves Observed in Infrared Satellite Imagery near Jan Mayen STEPHEN D. ECKERMANN E. O. Hulburt Center for Space Research, Naval Research Laboratory, Washington, D.C. DAVE BROUTMAN AND JUN MA Computational Physics, Inc., Springfield, Virginia JOHN LINDEMAN School of Computational Sciences, George Mason University, Fairfax, Virginia (Manuscript received 12 July 2005, in final form 20 January 2006) ABSTRACT A time-dependent generalization of a Fourier-ray method is presented and tested for fast numerical computation of high-resolution nonhydrostatic mountain-wave fields. The method is used to model moun- tain waves from Jan Mayen on 25 January 2000, a period when wavelike cloud banding was observed long distances downstream of the island by the Advanced Very High Resolution Radiometer Version 3 (AVHRR-3). Surface weather patterns show intensifying surface geostrophic winds over the island at 1200 UTC caused by rapid eastward passage of a compact low pressure system. The 1200 UTC wind profiles over the island increase with height to a jet maximum of ϳ60–70 m sϪ1, yielding Scorer parameters that indicate vertical trapping of any short wavelength mountain waves. Separate Fourier-ray solutions were computed using high-resolution Jan Mayen orography and 1200 UTC vertical profiles of winds and temperatures over the island from a radiosonde sounding and an analysis system. The radiosonde-based simulations produce a purely diverging trapped wave solution that reproduces the salient features in the AVHRR-3 imagery. Differences in simulated wave patterns governed by the radiosonde and analysis profiles are explained in terms of resonant modes and are corroborated by spatial ray-group trajectories computed for wavenumbers along the resonant mode curves.
    [Show full text]