DOCSLIB.ORG

Daytime and Nighttime Mid-Latitude Ionospheric Disturbances and Their Delayed Occurrence After Geomagnetic Activity

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Daytime and Nighttime Mid-Latitude Ionospheric Disturbances and Their Delayed Occurrence After Geomagnetic Activity Indian Journal of Radio & Space Physics Vol.22, February 1993,pp. i-io " Daytime and nighttime mid-latitude ionospheric disturbances and their delayed occurrence after geomagnetic activity GGBowman Department of Physics, The University of Queensland, Brisbane, Qld 4072, Australia Received 14 September 1992;revised received 15 December 1992 For a mid-latitude station the occurrence rates on ionograms of nighttime spread-F, daytime first-hop distortions (produced by medium-scale travelling ionospheric disturbances) and daytime second-hop spread are considered over a five-year period. Superposed-epoch analysis has been used to investigate the second-hop spread relative to days of enhanced activity in the other two parameters. The results show that all three parameters are closely related, with the second-hop spread being related to spread-F occurrence on the night following the daytime occurrence of this second-hop spread. Additional superposed-epoch analyses show that all three parameters are related to enhanced geomagnetic activity which is found to occur during an early-morning period which is displaced by three such periods from the days of enhanced activity for these parameters. Two peaks occur in this-early-morning period, one at 0400 local time, and the other close to local midnight. The paper concentrates particularly on this daytime second-hop phenomenon and sample ionograms are prescn led 10 illustrate some of the characteristics of the spread traces which are recorded. 1 Introduction performed to investigate whether or not daytime For mid-latitude regions this paper considers the disturbances can be related to geomagnetic activity delayed occurrence of nighttime spread-F, daytime with similar delayed occurrences. In the past it has not first-hop distortions and daytime second-hop spread been possible to associate with any certainty daytime following increased geomagnetic activity in disturbances with geomagnetic activity" - 8. This auroral-zone regions. It seems likely that all three could be due possibly to the fact that delayed parameters result from the passage of medium-scale occurrence was not considered and/or to the fact that travelling ionospheric disturbances (MS- TI Ds) daily geomagnetic indices were used rather than the (Refs I and 2). Interrelationships between these three hourly values which are available with the AE parameters (which are recorded on ionograms) will indices. also be considered. Particular attention will be paid to the daytime second-hop spread which has received 2 Experimental details and method of analysis little or no attention by investigators in the past, The special features of a modern ionosondc" possibly due to the reason that it was thought to result located on Bribie Island (36.1 "S, 218.1 °E - corrected from backscatter from ground irregularities. geomagnetic coordinates) at a site 55 km magnetically However recent results':", which indicate weaker north of Brisbane, Australia, have been used to record first-hop signals when this second-hop spread is on ionograms some of the characteristics of the recorded, as well as evidence of associations with second-hop daytime spread. These characteristics nighttime spread-F (ReD) and daytime MS-TIOs will be considered in the next section. This paper will (Ref.Z), suggest that irregularities in the ionosphere also consider statistically the occurrence rates of the are involved. three parameters which were mentioned in section I. Absorption events in the 0 region delayed by a These occurrence rates have been determined from number of days after increased geomagnetic activity ionograms recorded routinely every 15 minutes at at specific local times (in the early morning hours)" are Moggill, another recording site situated apparently associated with similar delayed approximately 60 km magnetically south of Bribie occurrences of mid-latitude spread-F (Ref.5). Island. The Moggill ionograms from 1979 to 1983 Therefore in view of the relationships between (inclusive) were used, although recordings for several daytime and nighttime disturbances, which will be months of 1982 were unavailable or unsuitable. explored further in this paper, analyses have been For each day or night of each month used, counts INDIAN J RADIO & SPACE PHYS, FEBRUARY 1993 IONOSPHERIC DISTURBANCES - MOGGILL (BRISBANE) JUNE 1981 (a) SPREAD-F (NIGHTTIME) 1800 - 0600 (DATE FOR 1800 - 0000 USED) 26 27 6 5 @@20@@ 17 1 17 64)@) 23 (33) 24 30 6 @) 7 11 9@@ 18 7 @ 19 14 • (b) FIRST-HOP DISTORTIONS (DAYTIME) 0600 -1800 6 10 4 @ 16 10 15@@ 12 6 11 13 13 9 6 9@ 9 @ 7 9 12 7 14 16 10@ 8 10 (e) SECOND-HOP SPREAD (DAYTIME) 0600 -1800 15 6 14 21 23 14 11 15 26 17 11 25@ 26 22 23 14@ 18@ 21 13 26@29@@@ 17 20 DATE 5 10 15 20 25 30 NUMBER OF EVENTS AT 15 - min INTERVALS AVERAGE MONTHLY VALUES (a) 23.7, (b) 12.0, (e) 22.0 o INDICATES VALUES> 1.33 AVERAGE .- Fig. I-A sample month (June 1981) of occurrence rates (at 15-min intervals) of the three parameters. namely. nighttime spread- F. daytime first-hop distortions. and daytime second-hop spread. Control dates are indicated by circles. were made of the number ofionograms showing (a) upper atmosphere (UA-NPD) most likely controls nighttime spread-F between the local times of 1800 the annual distributions of these parameters. As this and 0600, (b) first-hop daytime trace distortions appears to result from control of the MS-TID wave between local times of 0600 and 1800, and (c) amplitudes by the neutral-particle density, it seems second-hop daytime spread, again from 0600 to 1800. reasonable (in the absence of any other information) The local time is \0 h ahead of Universal Time. The m·~ •.u.u.iform distribution of disturbances counts obtained for the month of June 1981,which are ~~"')CIFCWIta",:~~e MS-TID wave quoted in Fig.l , show the variability of these three amplit'u~ •.•• ".., sia••• ~. As Bowman- parameters from day to day. The spread-F counts for shows, the o(,C1fnt:Ilteratr:~ \~ June solstice is each night were allocated the date of the first half of the at least 4 times greater than chafing the equinoctial night (i.e. from 1800 to 0000). Sets of controls were periods. obtained from each parameter determined by considering those counts in each month which were 3 Some characteristics of second-hop daytime spread greater than 1.33 times the average count for that The modem ionosonde? mentioned in section 2 was month. The days of these controls for June 1981 are responsible for the swept- and fixed-frequency indicated by circles on Fig.l. These controls have been ionograms which are presented in Figs 2 and 3, as used not only to investigate further relationships representative of second-hop daytime spread between these three parameters, but also to determine conditions. These conditions are most prevalent in what associations, if any, these days of enhanced sunspot-minimum years. In 1990and 1991 when the occurrence for each parameter might have with solar cycle was near its maximum. ionograms such as geomagnetic activity. Hourly values of the AE, AL and those which appear in Figs 2 and 3 were almost never AU indices have been used for geomagnetic activity. recorded. Except for Fig.3(a) all the ionograms on and superposed-epoch methods were employed to Figs 2 and 3 record primarily O-ray traces. However investigate these relationships. sometimes weak X-ray traces are also recorded [see It seems desirable to explain in some detail why it Fig.2(a)]. has been necessary to consider controls relative to The second-hop spread conditions during a short monthly averages rather than yearly averages. It has interval of time near 1420 LT on 23 June 1988 are been shown? for the parameters considered here and shown in Fig.2 by (a) the full-scale swept-frequency for spread-F generally from mid- and low-latitude ionogram, (b) a limited-scale ionogram with limited stations'? that modulation of occurrence rates by height and frequency parameters (a frequency range changing levels of the neutral-particle density of the of about 300 kHz), and (c) an ionogram similar to (b) (a) (b) 540 _(c) c 540 - 600 - o:l 520 - o < 400 - z 500 - > Z 200 - ~ 480 - I ? I I - I I I r 5.7 5.8 5.9 MHz 5 7 Mrfz 5.8 5.9 MHz 5.6 ~ 1420.09 1418.39 (GAIN SWEEP 30 dB IN 1S) ~ 1419.25 (23 JUNE 1988) C o (d) (e) (f ) rn 540- (3 E Z 2S o Vl -0 I-- 520 ::r: I rn (9 :;0 W 500 o I o Vl -.J -l « 480- C ::J :;0 l- o:l rr 1420.40 (1Os) 1421.15 (10s) :» 5.8 MHz 1422.04 (105) z :> o rn (g) Vl (h) (i) Rc !I.......~..,..~~~.~.I .:', ',:"., ' "':'~.:.•,:. 1\'--"" '''''''''''-'''~ ',' , '.. ",'\'\; o I!!I!I! 640 - ;....:...,~"\~~,~~,~~~'~,~,~..••,~~~'~"~~"~"'~"'\~ ....•. '~'~''''~ rn 600- - ~~~~;::~.;.;>-~~~;~~,,~~~.;,~~~~ ..•.:~~ o z 6 580 - z rn :j () .~~~~:> o 520 - -l I I I I 5 7 MHz 5.6 5.7 5.8 5.9 MHz <: 1249.47 (16 JUNE 1988) 1256.45 1259.31 ~ Fig. 2-Ionograms which illustrate some of the characteristics of daytime second-hop spread (The time quoted on each ionogram is the local time and the numoer appearing after decimal point shows seconds. e.g. 1419.25 means 14 hrs 19 min 25 s). w 4 INDIAN J RADIO & SPACE PHYS, FEBRUARY 1993 (a) (b) 600- I I I 6 MHz 5.25 5.50 1147.47 (6 SEP. 1989) 1149.37 (6 SEP. 1989) (GAINSWEEP 60 dB in O.Ss) (c) E ~ f- I CJ 400- W 550- I ....J -c 200- ::) f- a: s I I 520., 4 5 MHz I I I 4.0 4.2 4.4 MHz 4.6 1225.54 (30 MAY 1985) 1227.19 (30 MAY 1985) (e) (f) 1237.09 (30 MAY 1985) 1237.41 (30 MAY 1985) Fig.
Load more

Recommended publications
  • Consecutive Midnight Shifts
    Fatigue and Shiftwork: Consecutive Midnight Shifts Why is it so hard to work midnight shifts (“Mids”)? In a 24/7 operation, mids are unavoidable. It is what it is. The challenge is that you have to be alert when your circadian clock (internal body clock) is programmed to sleep. To prepare for a mid, you need to sleep in the daytime when your body clock is on alarm (resisting sleep). Working mids disrupts your sleep pattern which may lead to an increase in sleep debt (accumulation of getting less sleep than you need). Performance and alertness levels decrease with each passing day of shortened sleep. But what about consecutive mids? Are consecutive mids more fatiguing than working a single mid? Yes, because the more mids in a row, the larger the sleep debt, and the tougher the recovery. With one mid, sleep debt is acute and recovery (making up sleep by sleeping more on days off) is possible. With consecutive mids, sleep debt becomes chronic and recovery may require multiple full nights of recuperative sleep. Does working consecutive mid shifts affect performance and alertness? Yes. If you work a schedule associated with reduced opportunities for night time recovery sleep, that loss increases the likelihood of decrements in both work performance and alertness. These decrements are exponential during early morning hours when your body clock is at its lowest (around 0300-0500) and you naturally have the urge to sleep. It is scientifically proven that: • Incident/accident risk increases significantly on the 3rd and 4th consecutive mid shift
    [Show full text]
  • Morphology and Dynamics of the Venus Atmosphere at the Cloud Top Level As Observed by the Venus Monitoring Camera
    Morphology and dynamics of the Venus atmosphere at the cloud top level as observed by the Venus Monitoring Camera Von der Fakultät für Elektrotechnik, Informationstechnik, Physik der Technischen Universität Carolo-Wilhelmina zu Braunschweig zur Erlangung des Grades eines Doktors der Naturwissenschaften (Dr.rer.nat.) genehmigte Dissertation von Richard Moissl aus Grünstadt Bibliografische Information Der Deutschen Bibliothek Die Deutsche Bibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Internet über http://dnb.ddb.de abrufbar. 1. Referentin oder Referent: Prof. Dr. Jürgen Blum 2. Referentin oder Referent: Dr. Horst-Uwe Keller eingereicht am: 24. April 2008 mündliche Prüfung (Disputation) am: 9. Juli 2008 ISBN 978-3-936586-86-2 Copernicus Publications, Katlenburg-Lindau Druck: Schaltungsdienst Lange, Berlin Printed in Germany Contents Summary 7 1 Introduction 9 1.1 Historical observations of Venus . .9 1.2 The atmosphere and climate of Venus . .9 1.2.1 Basic composition and structure of the Venus atmosphere . .9 1.2.2 The clouds of Venus . 11 1.2.3 Atmospheric dynamics at the cloud level . 12 1.3 Venus Express . 16 1.4 Goals and structure of the thesis . 19 2 The Venus Monitoring Camera experiment 21 2.1 Scientific objectives of the VMC in the context of this thesis . 21 2.1.1 UV Channel . 21 2.1.1.1 Morphology of the unknown UV absorber . 21 2.1.1.2 Atmospheric dynamics of the cloud tops . 21 2.1.2 The two IR channels . 22 2.1.2.1 Water vapor abundance and cloud opacity . 22 2.1.2.2 Surface and lower atmosphere .
    [Show full text]
  • Flex Parking the Less You Park, the Less You Pay
    Flex Parking The less you park, the less you pay. PARKING PAYMENT EXAMPLES How It Works • You pay the rate in effect at the time you arrive. If your parking session bridges two different rate periods, you begin under the rate of the period that you arrived and pay that rate for either the first four hours (if you arrive within four hours BEFORE the rate changes) OR the first hour (if you arrive more than four hours BEFORE the rate changes). • Hours are counted from the minute that you arrive (for example 9:12am to 10:12am). • Parking is charged by the hour, there is no prorated amount for periods of less than an hour. You cannot pay for a portion of an hour. • Those who start parking M-F at 4:30pm or after (or anytime on Sat/Sun) will pay no more than $3.75. • Those who start parking M-F at 4:29pm or before will pay no more than $8. Examples 1. You arrive at 4:29pm and remain parked until midnight (or after). In the example below neither the daytime limit ($8) nor the nighttime limit ($3.75) are reached. Number Cumulative Time Period Rate in Effect of Hours Charge 4:29 to 8:29pm 4 $4 under daytime rate trip charge $4 8:29 to 11:29pm 3 $0.75 per hour for 3 hours under $6.25 nighttime rate (total $2.25) 11:29pm to 31 $0.75 for the portion of an hour parked $7 midnight minutes TOTAL CHARGE 7.5 $7 ($4 under daytime rate and $3 under $7 evening rate) 2.
    [Show full text]
  • Summer Midnight Sun
    NATIONAL WILDLIFE FEDERATION ARCTIC Summer Midnight Sun Summary ✔ Copies of student worksheets year, as the earth makes its orbit Students build a three- around the sun, the tilt produces dimensional model of the variable day lengths, and the rotation of the earth to change of seasons. When the appreciate the extremes of Background arctic is tilted away from the sun, daylight hours at different The Earth’s axis is an imaginary in the winter months, it gets little months of the year, and make line through its core, connecting or no sunlight. The sun appears connections between available the North and South poles. The to be at a very low angle on the sunlight and the growth and earth revolves around this axis, horizon, which also means less behavior of plants of the arctic. one full revolution per day. The intense light reaching the arctic. earth rotates so that during the On the other hand, when the Grade Level arctic is tilted toward the sun, in 5-8; 3-4 day we face the sun, and at night the summer months, it gets more Time Estimate we face away from the sun. one to two class periods. Because the earth is round, parts intense sunlight almost around the clock. Subjects: of it are closer to the sun than math, physics, geography, others. Parts that are closer Sunlight is critical to photosyn- science (nearer to the equator, lower lati- thesis, the process by which Skills: tude) experience more intense plants produce their own food. analysis, application, sunlight than parts that are Plants need water and sunlight in comparison, problem- further, such as the arctic at high order to photosynthesize.
    [Show full text]
  • The Transterminator Ion Flow at Venus at Solar Minimum
    EPSC Abstracts Vol. 5, EPSC2010-561, 2010 European Planetary Science Congress 2010 c Author(s) 2010 The transterminator ion flow at Venus at Solar Minimum A. G. Wood (1), S. E. Pryse (1), M. Grande (1) and the ASPERA team (1) Institute of Mathematics and Physics, Aberystwyth University, Aberystwyth, UK ([email protected] / Fax: +44- 1970-622826) Abstract The transterminator ion flow in the Venusian ionosphere is primarily driven by a pressure gradient which is caused by photoionisation [1]. At solar maximum this antisunward flow is the principle source of the nightside ionosphere [2]. Around solar minimum the ionopause is located at a lower altitude and it has been suggested that this would severely inhibit the transport process [3,4]. However, it is only within the last few years that extensive in-situ observations of ionospheric plasma under these solar conditions have been conducted. Observations of ions of ionospheric origin conducted by Venus Express throughout one Venus year sampled all local time sectors twice and flew through these sectors in opposing directions half a Venus year apart. These observations, conducted at high latitudes close to the solar terminator, showed asymmetries in both the dawn-dusk and noon-midnight planes. In the dawn- dusk direction greater numbers of ions were observed on the dusk side than on the dawn side. In the noon- midnight plane greater numbers of ions were observed on the dayside, although significant numbers of ions were seen nightward of the terminator. Collectively these observations suggest a nightward ion flow with the dawn-dusk asymmetry resulting from variations in the plasma density in the dayside ionosphere.
    [Show full text]
  • SPQ Module 18 – Sleeping Under the Midnight Sun
    SPQ Module 18 – Sleeping under the Midnight Sun There is twenty-four hour sunlight in Antarctica now, and on December 21 – the summer solstice - the sun will trace a perfect circle around the South Pole. How are Ray, Richard and Kevin responding to having to sleep in perpetual daylight, in a small tent that allows bright light to penetrate? Is the light interfering with their sleep? Scientists believe that prolonged lack of sleep may decrease length of life. Some believe this may shed some light on the fate of the Scott expedition. When Scott and his men set out for the South Pole in December 1911, they chose to march at ‘night’ and sleep during the ‘day’. Although the sun was up for the entire 24 hours, it was higher during the midday hours and lower during the midnight hours. Due to this differential height over the course of the day there was a similar difference in temperature, and the snow was firmer for marching during the cooler midnight hours, and it was warmer for sleeping during the midday hours. There have been many theories about what led to Robert Did You Know? Falcon Scott and his men’s death. One novel hypothesis is that profound sleep deprivation The world record precipitated their demise. In the surviving journals for sleeplessness from the expedition reference is made by the British is 264 hours team to the difficulties they were having getting proper (eleven days), set sleep. Their insomnia was likely attributable to the by an 18 year old sodden or frozen sleeping bags in which they slept, as American in 1965.
    [Show full text]
  • It Happened at Midnight
    Dr Maurice M. Mizrahi B”H D’var Torah on Pessaḥ It Happened at Midnight On the first night of Passover, after the seder meal, Jews traditionally recite -Vayehi Ba וַיְהִ י בַחֲצִ י הַלַיְלָה) ”a poem, a piyyut, called “It Happened at Midnight ḥatzi Ha-laylah). It was written in the 6th century by Yannai, who lived in Eretz Yisrael. The verses recount many miracles that happened in Jewish history at midnight, on the first night of Pessah. The most important one is the Exodus from Egypt, which explains why it is included in the seder. Indeed, the Torah says the process for the Exodus started at midnight: וַיֹֹּ֣אמֶרמֹשֶֶׁ֔ה כֹֹּ֖ ה אָמַֹּ֣ר יְהוָָ֑ה כַחֲצֹֹּ֣ ת הַלֶַׁ֔ יְלָה אֲנִִ֥י יֹוצ ֹּ֖א בְתִֹ֥וְך מִצְרָָֽ יִם Moses said, “Thus says the Lord: About midnight I will go forth among the Egyptians.” [Exodus 11:4] וַיְהִֹּ֣י׀ בַחֲצִֹּ֣ י הַלַַּ֗ יְלָהוַָֽיהוָה֮ הִכָֹּ֣ה כָל־בְ כֹור֮ בְאֶֹּ֣רֶץ מִצְרַ יִם In the middle of the night the Lord struck down all the first-born in the land of Egypt. [Exodus 12:29] First, it must be noted that in Judaism, midnight is not necessarily 12am but is literally the midpoint of the night, halfway between sunset and sunrise. That point is called chatzot. In winter, when nights are long, midnight is after 12am; in summer, when nights are short, it is after 12am. It varies every day. In all, thirteen miracles are listed in the poem, all happening on the first night of Pessah at midnight. We will first list them, then try to answer the question: What is so special about midnight? The other twelve miracles are as follows: -God allows Abraham to defeat the four kings who kidnapped his nephew Lot: וַיחָל ֵ֨ ק עֲל יהֶֶ֧ם׀ לַַ֛יְלָה הִ֥ ּואוַעֲבָדָֹּ֖יו וַיַכ ָ֑ם At night, [Abraham] and his servants fought against them and defeated them.
    [Show full text]
  • The Length of Days 1
    MODELLING EXERCISES The length of days 1 (by Alan Champneys) Have you ever thought about what a graph of the number of hours of daylight throughout the year might look like? Clearly it depends on lattitude. Here is a graph for Bristol which has an angle of lattitude φ = 51◦ (north). Looks like a sine wave, doesn’t it? But is it exactly a sine wave? and how would we prove it? Think about what exactly causes the length of the days to change. Discuss in your group. For the rest of this exercise we are going to try to look test a formula for the daylength anywhere on the Earth. MEI / AMSP & BRISTOL ENGINEERING MATHS DEGREE PROGRAMME asmp.org.uk — www.bristol.ac.uk/engmaths MODELLING EXERCISES Solution Daylight hours depend on the tilt of the Earth as it goes on its orbit around the sun. In the northern hemisphere Summer the earth is tilted so that the sun is over the northern tropic (of Cancer) which has an angle of latitude φ = 23:45◦N. In winter it is over the southern tropic (of Capricorn ) at φ = −23:45◦S. This causes days to be longer in northern latitudes during Summer. But how much longer? Clearly a sine wave would be a good first guess as a function for the length of the days. But there is a problem. This function is no use when we get towards the poles. For example, the northern Russian city of Murmusk is inside the arctic circle, and its graph of daylight hours is highly non-sinusoidal.
    [Show full text]
  • Sunrise, Sunset…Or Not?
    Sunrise, Sunset…or Not? Sunrise, Sunset…or Not? Sunrise, sunset. It’s nice to know we can rely on the sun to come up in the morning and go down at night. The sun is a wonderful thing. It is a star, and its light shines onto our planet. It is the ultimate source of energy. It heats our planet and makes life on Earth possible. Without the sun, trees and plants wouldn’t get the light energy they need to grow. Without this light, we humans would have a hard time finding enough food to eat. Without the sun, life as we know it would be very different. We can always rely on the sun. Sunrise, sunset. Summer days may be longer than winter days, but the sun always seems to do the same thing: it goes down at night and comes up for the day. But that’s not always true. In some parts of the world, the sun can be up in the sky for the entire day. During the summer, the Earth is tilted to the sun so much that the sun in northern Alaska never goes below the horizon. In Barrow, Alaska, the sun doesn’t even set for almost three months! This phenomenon is called midnight sun. Try sleeping through that! During the winter, the Earth is tilted in such a way that the sun doesn’t come over the horizon in northern Alaska for over two months. Northern Alaska is located in the Arctic Circle, an area at the top of the earth.
    [Show full text]
  • The Solar System Questions KEY.Pdf
    THE SOLAR SYSTEM 1. The atmosphere of Venus is composed primarily of A hydrogen and helium B carbon dioxide C methane D ammonia Base your answers to questions 2 through 6 on the diagram below, which shows a portion of the solar system. 2. Which graph best represents the relationship between a planet's average distance from the Sun and the time the planet takes to revolve around the Sun? A B C D 3. Which of the following planets has the lowest average density? A Mercury B Venus C Earth D Mars 4. The actual orbits of the planets are A elliptical, with Earth at one of the foci B elliptical, with the Sun at one of the foci C circular, with Earth at the center D circular, with the Sun at the center 5. Which scale diagram best compares the size of Earth with the size of Venus? A B C D 6. Mercury and Venus are the only planets that show phases when viewed from Earth because both Mercury and Venus A revolve around the Sun inside Earth's orbit B rotate more slowly than Earth does C are eclipsed by Earth's shadow D pass behind the Sun in their orbit 7. Which event takes the most time? A one revolution of Earth around the Sun B one revolution of Venus around the Sun C one rotation of the Moon on its axis D one rotation of Venus on its axis 8. When the distance between the foci of an ellipse is increased, the eccentricity of the ellipse will A decrease B increase C remain the same 9.
    [Show full text]
  • The Transterminator Ion Flow at Venus at Solar Minimum
    The transterminator ion flow at Venus at Solar Minimum A. G. Wood[1, 2], S. E. Pryse[1], M. Grande[1], I. C. Whittaker[1, 3], A. J. Coates[4], K. Husband[4], W. Baumjohann[5], T. Zhang[5], C. Mazelle[6], E. Kallio[7], M. Fränz[8], S. McKenna-Lawlor[9] and P. Wurz[10] [1] Institute of Mathematics and Physics, Aberystwyth University, Aberystwyth, Wales, UK [2] School of Engineering, University of Liverpool, Liverpool, UK [3] University of St. Andrews, St Andrews, Scotland, UK [4] Mullard Space Science Laboratory, University College London, UK [5] Space Research Institute, Austrian Academy of Sciences, Graz, Austria [6] Institut de Recherche en Astrophysique et Planétologie, Toulouse, France [7] Finnish Meteorological Institute, Helsinki, Finland [8] Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany [9] Space technology Ltd., National University of Ireland, Ireland [10] University of Bern, Physikalisches Institut, Switzerland Abstract The transterminator ion flow in the Venusian ionosphere is observed at solar minimum for the first time. This antisunward flow, which transports ions from the day to the nightside, is primarily driven by a pressure gradient caused by photoionisation. Although such a flow was been observed previously around solar maximum, at solar minimum the transport process is severely inhibited by the lower altitude of the ionopause. Observations of ionospheric plasma at solar minimum are routinely made by ASPERA-4 onboard the Venus Express spacecraft and constitute the first extensive in-situ measurements of this plasma under these solar conditions. Observations of ions of ionospheric origin showed asymmetries in both the dawn- Page 1 dusk and noon-midnight planes for ions of ionospheric origin.
    [Show full text]
  • Midnight in Broad Daylight
    MIDNIGHT IN BROAD DAYLIGHT Midnight_Final_464_1002_CL.indd 1 10/2/15 2:33 PM MIDNIGHT IN BROAD DAYLIGHT A J A P A NESE A MERIC A N F A MILY C A UGHT B ETWEEN T WO W ORLDS Pamela Rotner Sakamoto Midnight_Final_464_1002_CL.indd 2 10/2/15 2:33 PM MIDNIGHT IN BROAD DAYLIGHT A J A P A NESE A MERIC A N F A MILY C A UGHT B ETWEEN T WO W ORLDS Pamela Rotner Sakamoto HARPER An Imprint of HarperCollinsPublishers Midnight_Final_464_1002_CL.indd 3 10/2/15 2:33 PM Copyright midnight in broad daylight. Copyright © 2016 by Pamela Rotner Saka- moto. All rights reserved. Printed in the United States of America. No part of this book may be used or reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles and reviews. For information, address Harper Collins Publishers, 195 Broadway, New York, NY 10007. Harper Collins books may be purchased for educational, business, or sales pro- motional use. For information, please e- mail the Special Markets Department at [email protected]. first edition Designed by Michael Correy Library of Congress Cataloging-in-Publication Data Sakamoto, Pamela Rotner Midnight in broad daylight : a Japanese American family caught between two worlds / Pamela Rotner Sakamoto. — First edition. pages cm Includes bibliographical references and index. ISBN 978-0-06-235193-7 1. Fukuhara, Harry K., 1920–2015. 2. Fukuhara, Pierce, 1922–2008. 3. Fukuhara, Frank, 1924–2015. 4. World War, 1939–1945—Japanese Americans. 5. Japanese American families—Washington—Seattle.
    [Show full text]