Science.gov

Sample records for matter polar mesosphere

  1. On the lack of southern hemisphere polar mesosphere summer echoes

    NASA Astrophysics Data System (ADS)

    Balsley, B. B.; Woodman, R. F.; Sarango, M.; RodríGuez, R.; Urbina, J.; Ragaini, E.; Carey, J.; Huaman, M.; Giraldez, A.

    1995-06-01

    We report VHF radar observations of the southern high-latitude mesopause region using wind profilers that were installed recently on King George Island, Antarctica, and Ushuaia, Argentina. Briefly, our observations, which were made during January and February 1993, show almost no evidence of so-called polar mesosphere summer echoes, or PMSE. Since these echoes are a predominant feature of the northern high-latitude mesosphere in summer, their absence in the southern hemisphere is both surprising and intriguing. In this paper we present evidence demonstrating the virtual absence of the echoes and demonstrate that our systems were capable of detecting them had they been present. We also outline some of the consequences of this intriguing result, which are supported by observed hemispheric differences in polar mesospheric clouds, mesospheric temperatures, upper atmospheric gravity wave activity, and mean circulation patterns.

  2. Polar mesosphere summer echoes (PMSE) a southern hemisphere perspective

    NASA Astrophysics Data System (ADS)

    Morris, R. J.; Murphy, D. J.; Klekociuk, A. R.; Holdsworth, D. A.

    The existence of Polar Mesosphere Summer Echoes PMSE in the Southern Hemisphere SH has recently been confirmed using HF radar Ogawa et al 2002 MST radar Morris et al 2004 and a Dynasonde Jarvis et al 2005 following earlier observations using MST radar Woodman et al 1999 These studies spanned the geographic latitudes 62 1 r S Machu Picchu 68 6 r S Davis 69 0 r S Syowa and 75 5 r S Halley Bay The emerging array of SH SuperDARN radars provide an opportunity to extend the spatial coverage of PMSE observations An understanding of the occurrence and intensity of PMSE against latitude in the SH is needed to facilitate a comparison with the better spatial coverage of Northern Hemisphere NH PMSE observations Such a comparison will contribute to the ongoing debate as to whether PMSE can provide a proxy for mesosphere temperature and thus shed light on the existence of any interhemispheric asymmetry or otherwise in the polar mesosphere regions The argument for different polar mesosphere environments spawned in part by the reported lack of SH PMSE observations Recent PMSE reflectivity and intensity results from Davis 68 6 r S and Andenes 69 0 r N are given The characteristics and morphology of PMSE events above these Antarctic stations are considered in the context of the thermal and dynamical state of the mesosphere as deduced from satellite i e SABER and AURA and radar i e MF and MST observations respectively A brief account of recent coincident PMSE MST radar and Polar Mesospheric Cloud PMC

  3. Polar mesosphere winter echoes and ionospheric heating experiments

    NASA Astrophysics Data System (ADS)

    Belova, Evgenia

    Polar Mesosphere Winter Echoes (PMWE) are strong radar backscatters from altitudes between 50 and 80 km observed by VHF radars in the polar latitudes during winter time. They are seen when there is extra D-region ionization due to e.g. energetic solar protons or magnetospheric electron precipitation. Last 5 years there were many studies related to the properties, conditions and generation mechanism of PMWE, however for their complete and clear understanding more work is definitely needed. On the other hand, with studying PMWE we have possibility to learn about properties of their background, i.e. the polar winter mesosphere, the region, which is very difficult for diagnostics. Havnes (2004) proposed a new experimental method for probing ionospheric plasma during P(olar) M(esosphere) S(ummer) E(choes), called the PMSE overshoot effect. It is based on artificial heating of electrons in the PMSE region by HF radiowave with a special modulation pattern. It was shown to be capable of estimation of properties of background dusty plasma, electron temperature enhancement, and even of detection of the electron byte-outs. The method applied for PMSE conditions confirmed a presence of charged particles of a few tens nm size in the summer polar mesosphere. Recently this method was applied for winter conditions in the polar mesosphere where such particles composed of water ice are not expected because of higher temperatures. However, a weak overshoot effect was detected, and it was speculated to be indication of a presence of very small dust particles, likely meteoric smoke particles. We present the results of the experiment on January 16, 2008 where strong PMWE were detected with the European incoherent scatter (EISCAT) VHF radar (224 MHz) located near Tromso, Norway and the Heating facility was used for the PMWE overshoot modulation.

  4. Refinement of the DROPPS Polar Summer Mesosphere Particle Data

    NASA Astrophysics Data System (ADS)

    Webb, P.; Goldberg, R.; Pesnell, W.; Voss, H.; Assis, M.

    The two Black Brant payloads flown during the DROPPS Distribution and Role of Particles in the Polar Summer Mesosphere rocket program were launched during early July 1999 from And o ya Rocket Range ARR Norway The purpose was to investigate the polar summer mesosphere particularly polar mesospheric summer echoes PMSE Both DROPPS payloads included front mounted side by side Particle Impact Detector PID charge and mass telescopes Computer simulations have shown that the PID telescopes have the potential to detect atmospheric ice particles within the mesosphere having dimensions of a few nanometers Ice particles of nanometer size are believed to be responsible for PMSEs through the process of scavenging Evidence for this process is suggested by the presence of an electron biteout observed in the same region as the observation of nanometer size particles at an altitude of sim 82-87 km over And o ya during the first DROPPS launch sequence Evidence for this dusty plasma was observed independently by several instruments aboard the DROPPS payload By comparing PID observations with the computer simulations we can obtain information concerning the properties of the PMSE particles including their rocky core size ice mantle thickness and distribution We have previously presented results from an analysis of the two detectors that suggested on the first flight particles with radius of approximately 2 nm were present in the PMSE layer We have recently realised that our interpretation of the PID data required further refinement For example we have now

  5. Power spectra of mesospheric velocities in polar regions

    NASA Technical Reports Server (NTRS)

    Czechowsky, P.; Ruster, R.

    1985-01-01

    The mobile SOUSY radar was operated on Andoya in Northern Norway during the MAP/WINE campaign from November 1983 to February 1984 and for about two weeks in June 1984 to study the seasonal dependence of mesospheric structures and dynamics at polar latitudes. During the winter period, measurements were carried out on 57 days, primarily in coordination with the schedule of the rocket experiments. Echoes were detected in the troposphere and stratosphere up to 30 km and at mesospheric heights from about 50 to 90 km with a distinct maximum around noon. In summer, the radar system was operated continuously from 19th to the 28th of June 1984. Echoes occurred almost for 24 hours in the height range from 70 to 95 km showing no recognizable diurnal variation. Similar observations in polar latitudes were carried out for several years with the Poker Flat Radar in Alaska.

  6. Radar scattering from the summer polar mesosphere: Theory and observations

    SciTech Connect

    Cho, J.Y.N.

    1993-01-01

    The anomalously large radar reflectivities observed in the summer polar mesosphere have eluded satisfactory explanation until now. The author proposes that the following chain of causality is responsible for the so-called polar mesosphere summer echoes (PMSE): The uniquely low temperature in the summer mesopause produce ice aerosols. Because the aerosols exist in a plasma, they become electrically charged. The ambient electrons become coupled to the aerosols through electric fields and their effective diffusivity is retarded due to the large size of the aerosols. The reduction in diffusivity allows electron density inhomogeneities to be maintained at the radar Bragg scales. The radar waves are then scattered by the inhomogeneities. The above concept is supported by developing a quantitative theory of ambipolar diffusion in the mesosphere. The results to isotropic turbulence and Fresnel radar scatter are applied to show that the observed radar reflectivities can be explained by the theory. It is shown that the presence of realistic charged aerosols are sufficient to explain PMSE. The author also shows that dressed aerosol radar scatter can only apply to echoes detected by UHF radars. The data is taken with the Sondrestrom 1.29-GHz radar and attribute it to dressed aerosol scatter. The author used the Cornell University portable radar interferometer (CUPRI) to observe the mesosphere while rockets carrying in situ sensors were flown through two PMSE occurrences and a noctilucent cloud/PMSE event. The first simultaneous height comparison between noctilucent clouds and PMSE show that the radar scattering region was near or slightly above the visible cloud layer. The author also infers from aspect sensitivity measurements and Doppler spectrograms that there were two distinct types of PMSE: Enhanced turbulent scatter and partial (Fresnel) reflection from steep edges in the electron density. Both mechanisms require an anomalously low electron diffusion coefficient.

  7. PoSSUM: Polar Suborbital Science in the Upper Mesosphere

    NASA Astrophysics Data System (ADS)

    Reimuller, J. D.; Fritts, D. C.; Thomas, G. E.; Taylor, M. J.; Mitchell, S.; Lehmacher, G. A.; Watchorn, S. R.; Baumgarten, G.; Plane, J. M.

    2013-12-01

    Project PoSSUM (www.projectpossum.org) is a suborbital research project leveraging imaging and remote sensing techniques from Reusable Suborbital Launch Vehicles (rSLVs) to gather critical climate data through use of the PoSSUM Observatory and the PoSSUM Aeronomy Laboratory. An acronym for Polar Suborbital Science in the Upper Mesosphere, PoSSUM grew from the opportunity created by the Noctilucent Cloud Imagery and Tomography Experiment, selected by the NASA Flight Opportunities Program as Experiment 46-S in March 2012. This experiment will employ an rSLV (e.g. the XCOR Lynx Mark II) launched from a high-latitude spaceport (e.g. Eielson AFB, Alaska or Kiruna, Sweden) during a week-long deployment scheduled for July 2015 to address critical questions concerning noctilucent clouds (NLCs) through flights that transition the cloud layer where the clouds will be under direct illumination from the sun. The 2015 Project PoSSUM NLC campaign will use the unique capability of rSLVs to address key under-answered questions pertaining to NLCs. Specifically, PoSSUM will answer: 1) What are the small-scale dynamics of NLCs and what does this tell us about the energy and momentum deposition from the lower atmosphere? 2) What is the seasonal variability of NLCs, mesospheric dynamics, and temperatures? 3) Are structures observed in the OH layer coupled with NLC structures? 4) How do NLCs nucleate? and 5) What is the geometry of NLC particles and how do they stratify? Instrumentation will include video and still-frame visible cameras (PoSSUMCam), infrared cameras, a mesospheric temperatures experiment, a depolarization LiDAR, a mesospheric density and temperatures experiment (MCAT), a mesospheric winds experiment, and a meteoric smoke detector (MASS). The instrument suite used on PoSSUM will mature through subsequent campaigns to develop an integrated, modular laboratory (the ';PoSSUM Observatory') that will provide repeatable, low cost, in-situ NLC and aeronomy observations as well

  8. Large amplitude nonlinear structures in the nighttime polar mesosphere

    NASA Astrophysics Data System (ADS)

    Maharaj, Shimul K.; Bharuthram, Ramashwar; Singh Lakhina, Gurbax; Muralikrishna, Polinaya; Singh, Satyavir

    2016-07-01

    The existence of large amplitude potential structures will be investigated for a plasma composed of negative ions, positive ions, electrons and an additional fourth component of charged (usually positive) nano-sized ions in an attempt to model the plasma composition in the nighttime polar mesosphere (˜80 - 90 km altitude) [1]. The fourth ionic component becomes positively charged if there is a high enough concentration of negative ions which are sufficiently heavy. The positive charge on the fourth component can be explained by the capture of currents, and is not a result of photo-emission and secondary electron emission processes. Consequently, if the negative ions are much lighter, then the fourth ion component will become negatively charged. The charged ion species will be treated as inertial species which are cold or adiabatic, whilst the electrons will be considered to be Boltzmann-distributed (isothermal). Taking into consideration not only the dynamics of the heaviest species (dust-acoustic) but also the lighter ions (ion-acoustic), the theoretical study will use the Sagdeev pseudo-potential formalism to explore the existence of arbitrary amplitude solitons and double layer potential structures. [1] Observations of positively charged nanoparticles in the nighttime polar mesosphere, M. Rapp, J. Hedin, I. Strelnikova, M. Friederich, J. Gumbel, and F.˜J. Lübken, Geophys. Res. Letters. 32, L23821, doi:10.1029/2005GL024676 (2005).

  9. Analysis of Satellite-Based Polar Mesospheric Cloud Observations

    NASA Astrophysics Data System (ADS)

    Benze, Susanne

    Polar Mesospheric Clouds (PMCs) are thin water-ice clouds that form in the summer polar mesopause region. Since PMCs are sensitive to changes in the upper atmospheric temperature and water vapor abundance, they can be used to understand the dynamics of the upper mesosphere. It has also been suggested that they are important indicators of mesospheric climate change. PMCs have been successfully observed from the ground and with remote sensing instruments, for example the Cloud Imaging and Particle Size (CIPS) experiment on the Aeronomy of Ice in the Mesosphere (AIM) satellite, and the Solar Backscatter UltraViolet (SBUV) instruments. This thesis presents validation of CIPS observations by showing a comparison of PMC occurrence frequency, cloud and background albedo as observed by CIPS and SBUV. It is found that frequency and cloud albedo are in excellent agreement, with a small (10%) low bias in the CIPS v3.20 operational frequencies at more equatorward PMC latitudes on the descending node. The background albedo, however, shows a still unresolved bias that depends on hemisphere. Overall, the results show that CIPS PMC data are valid for scientific analysis. Furthermore, this thesis investigates and quantifies the relative importance of several coupling mechanisms that contribute to variability in the PMC season onset, such as the solar cycle and intra-hemispheric and inter-hemispheric coupling. It is found that the Southern Hemisphere (SH) PMC season onset is controlled primarily by the timing of the SH stratospheric wind reversal from its winter to summer state, with a smaller but still important contribution from the solar cycle. Inter-hemispheric coupling triggered by winter stratospheric wind variations plays a significant role in controlling the Northern Hemisphere (NH) PMC season onset dates, again with additional control by the solar cycle. These couplings explain most of the observed variability in the PMC onset dates as observed by SBUV over the past three

  10. The PHOCUS Project: Particle Interactions in the Polar Summer Mesosphere

    NASA Astrophysics Data System (ADS)

    Gumbel, J.; Hedin, J.; Khaplanov, M.

    2012-12-01

    On the morning of July 21, 2011, the PHOCUS sounding rocket was launched from Esrange, Sweden, into strong noctilucent clouds (NLC) and polar mesosphere summer echoes (PMSE) observed by the Esrange lidar and the ESRAD MST radar. The aim of the PHOCUS project (Particles, Hydrogen and Oxygen Chemistry in the Upper Summer mesosphere) is to study mesospheric particles (ice and meteoric smoke) and their interaction with their neutral and charged environment. Starting out from first ideas in 2005, PHOCUS has developed into a comprehensive venture that connects to a number of new and renewed scientific questions. Interactions of interest comprise the charging and nucleation of particles, the relationship between meteoric smoke and ice, and the influence of these particles on gas-phase chemistry. This presentation gives an overview of the campaign and scientific results. The backbone of the campaign was a sounding rocket with 18 instruments from 8 scientific groups in Sweden, Norway, Germany, Austria and the USA. Atmospheric composition and ice particle properties were probed by a set of optical instruments from Stockholm University, in collaboration with the University in Trondheim. Exciting new instrument developments concerned microwave radiometers for in situ measurements of water vapour at 183 and 558 GHz by Chalmers University of Technology. Charged particles were probed by impact detectors from the University of Colorado, the University of Tromsø and the Leibniz Institute of Atmospheric Physics (IAP), complemented by direct particle sampling from Stockholm University. The neutral and charged background state of the atmosphere was quantified by the Technical University Graz, IAP, and the Norwegian Defence Research Establishment. Important ground-based instrumentation included the Esrange lidar, the ESRAD MST radar, the SkiYMET meteor radar and EISCAT.

  11. Growth, sedimentation, heating and charging of dust particles in the polar summer mesosphere

    SciTech Connect

    Klumov, B. A.

    2009-11-10

    Some peculiarities of the Earth's dusty ionosphere are considered using as an example the polar summer mesosphere. We discuss in detail growth and sedimentation of nanosized dusty/smoke particles in the upper atmosphere; the impact of nano/micro-particles optical properties on their heating and charging; for instance, it has been shown that oppositely charged dust particles may present in the polar summer mesosphere. We present a simple one-dimensional growth-sedimentation model; the model predicts the size and altitude distributions of dust particles in the mesosphere; e.g, the model predicts the bimodal size distribution of the dust particles.

  12. Mesosphere light scattering depolarization during the Perseids activity epoch by wide-angle polarization camera measurements

    NASA Astrophysics Data System (ADS)

    Ugolnikov, Oleg S.; Maslov, Igor A.

    2014-03-01

    The paper describes the study of scattered radiation field in the mesosphere basing on wide-angle polarization camera (WAPC) measurements of the twilight sky background and single scattering separation procedure. Mid-August observations in 2012 and 2013 show the decrease of single scattering polarization value probably related with Perseids meteor dust moderation in the upper mesosphere. Effect correlates with activity of tiny fraction of Perseids shower. Polarization and temperature analysis allows estimating the altitude of dust layer and character polarization of dust scattering.

  13. Retrieving mesospheric winds and gravity waves using high resolution radar measurements of polar mesospheric summer echoes with MAARSY

    NASA Astrophysics Data System (ADS)

    Stober, G.; Sommer, S.; Schult, C.; Chau, J. L.; Latteck, R.

    2013-12-01

    The Middle Atmosphere Alomar Radar System (MAARSY) located at the northern Norwegian island of Andøya (69.3 ° N, 16° E) observes polar mesosphere summer echoes (PMSE) on a regular basis. This backscatter turned out to be an ideal tracer of atmospheric dynamics and to investigate the wind field at the mesosphere/lower thermosphere (MLT) at high spatial and temporal scales. MAARSY is dedicated to explore the polar mesosphere at such high resolution and employs an active phased array antenna with the capability to steer the beam on a pulse-to-pulse basis, which permits to perform systematic scanning of PMSE and to investigate the horizontal structure of the backscatter. The radar also uses a 16 channel receiver system for interferometric applications e.g. mean angle of arrival analysis or coherent radar imaging. Here we present measurements using these features of MAARSY to study the wind field at the MLT applying sophisticated wind analysis algorithms such as velocity azimuth display or volume velocity processing to derive gravity wave parameters such as horizontal wave length, phase speed and propagation direction. Further, we compare the interferometrically corrected and uncorrected wind measurements to emphasize the importance to account for likely edge effects using PMSE as tracer of the dynamics. The observations indicate huge deviations from the nominal beam pointing direction at the upper and lower edges of the PMSE altering the wind analysis.

  14. Enhancement of odd nitrogen modifies mesospheric ozone chemistry during polar winter

    NASA Astrophysics Data System (ADS)

    Verronen, P. T.; Lehmann, R.

    2015-12-01

    Energetic particle precipitation (EPP) enhances odd nitrogen (NOx) in the polar upper atmosphere. Model studies have reported a solar cycle response in mesospheric ozone (O3) caused by EPP-related NOx enhancements which are included by applying a vertical NOx flux at around 80 km. However, it is not clear how O3 can be affected when the main chemical catalyst of odd oxygen (Ox = O + O(1D) + O3) loss in the mesosphere is odd hydrogen (HOx). Here we use a 1-D atmospheric model and show how enhanced NOx affects mesospheric chemistry and changes HOx partitioning, which subsequently leads to increase in Ox loss through standard HOx-driven catalytic cycles. Another, smaller increase of Ox loss results from HOx storage in HNO3 during night and its release by daytime photodissociation. Our results suggest that EPP, through NOx enhancements, could have a longer-term effect on mesospheric HOx and Ox in polar winter.

  15. Observations of Polar Mesospheric Clouds from Space: A SME Legacy

    NASA Astrophysics Data System (ADS)

    Russell, J. M.; Bailey, S. M.

    2011-12-01

    Noctilucent Clouds (also referred to as Polar Mesospheric Clouds), were first reported from ground visual observations in 1885. Since that time there has been a growing public and scientific interest in these beautiful, iridescent clouds for a variety of reasons. The Solar Mesospheric Explorer (SME) satellite made forerunner observations of PMCs 30 years ago and results flowing from these observations laid the groundwork for the scientific state of knowledge that exists today. The recognition of and scientific interest in this high altitude cloud layer, was in large measure stimulated by analysis of SME results. PMC signals were seen in SME limb-scanning measurements, as large increases in scattered radiance in the 0.2μm - 0.3μm spectral region, at heights near 80 km, at latitudes 60-90°N and 60-90°S and during the summer season. The measurements showed a pronounced tendency for the brighter clouds to exhibit greater forward-scattering behavior, providing some of the first indications of the cloud particle sizes. SME results suggested that the maximum particle size was in the 70nm range. The mission provided the first global view of PMCs and the first climatology of their behavior. SME showed that the cloud season ends about 60 days after solstice, and that the maximum occurrence frequency appears around 1 to 3 weeks following solstice. The results also led to the correct speculation that variations of temperature and/or the accompanying upward advective water vapor flux are responsible for the seasonal PMC variation. This suggestion was made many years before it was confirmed that PMCs are made up mostly of water ice. This paper will present an overview of space-based observations of PMCs and scientific implications of the data. The clouds have been extensively observed by a number of satellite experiments including SME, HALOE, SNOE, SCIAMACHY, OSIRIS, SBUV, OMI and AIM. The latter mission, AIM, is the first mission dedicated to the study of PMCs with the

  16. Studies of Polar Mesospheric Clouds from Observations by the Student Nitric Oxide Explorer

    NASA Technical Reports Server (NTRS)

    Bailey, Scott M.

    2005-01-01

    The Geospace Sciences SR&T award NAG5-12648 "Studies of polar mesospheric clouds from observations by the Student Nitric Oxide Explorer" has been completed. The project was very successful in completing the proposed objectives and brought forth unexpected results in the study of Polar Mesospheric Clouds (PMCs). This work has provided key results to the community, provided valuable experience to two students, and inspired new research and collaborations with other research groups. Here we briefly summarize the progress and the scientific results.

  17. The DROPPS Program: A Rocket/Lidar/Radar Study of the Polar Summer Mesosphere

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Holzworth, R. H.; Schmidlin, F. J.; Voss, H. D.; Tuzzolino, A. J.; Croskey, C. L.; Mitchell, J. D.; vonZhan, U.; Singer, W.

    1999-01-01

    During July of 1999, two sequences of rockets were launched from the Norwegian rocket range in Andoya, Norway. The purpose of these studies was to investigate the properties of the polar summer mesosphere, particularly relating to polar mesospheric summer echoes (PMSE) and their possible relationship to noctilucent clouds (NLC). Each of two sequences was anchored with a DROPPS Black Brant payload, consisting of 20 instruments to measure the electrodynamic and optical structure of the mesosphere and lower thermosphere. These were provided by participants from five American and two European scientific laboratories. The DROPPS (Distribution and Role of Particles in the Polar Summer) payloads were each accompanied by a sequence of meteorological rockets, and by several European payloads designed to study electrodynamics structure of the same region. ALOMAR (Arctic Lidar Observatory for Middle Atmosphere Research) Lidars, and MF (Medium Frequency) and MST (Mesosphere, Stratosphere, and Troposphere) Radars were used to continuously monitor the mesosphere for NLCs and PMSEs respectively. EISCAT VHF (European Incoherent Scatter Radar Very High Frequency) radar provided similar information about PMSEs downstream from the launch site. Sequence 1 was launched on the night of 5-6 July into a strong PMSE display coupled with a weak NLC at the low end of the PMSE. Sequence 2 was launched on the early morning of 14 July into a strong NLC with no PMSE evident. Here we describe the details of the program along with preliminary results.

  18. Temperature Trends in the Polar Mesosphere between 2002-2007 using TIMED/SABER Data

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Kutepov, Alexander A.; Pesnell, William Dean; Latteck, Ralph; Russell, James M.

    2008-01-01

    The TIMED Satellite was launched on December 7, 2001 to study the dynamics and energy of the mesosphere and lower thermosphere. The TIMED/SABER instrument is a limb scanning infrared radiometer designed to measure a large number of minor constituents as well as the temperature of the region. In this study, we have concentrated on the polar mesosphere, to investigate the temperature characteristics as a function of spatial and temporal considerations. We used the recently revised SABER dataset (1.07) that contains improved temperature retrievals in the Earth polar summer regions. Weekly averages are used to make comparisons between the winter and summer, as well as to study the variability in different quadrants of each hemisphere. For each year studied, the duration of polar summer based on temperature measurements compares favorably with the PMSE (Polar Mesospheric Summer Echoes) season measured by radar at the ALOMAR Observatory in Norway (69 N). The PMSE period should also define the summer period suitable for the occurrence of polar mesospheric clouds. The unusual short and relatively warm polar summer in the northern hemisphere

  19. Long term observations of polar mesospheric echoes at Andøya

    NASA Astrophysics Data System (ADS)

    Latteck, Ralph; Strelnikova, Irina; Renkwitz, Toralf; Sommer, Svenja

    2016-04-01

    Polar mesosphere summer echoes (PMSE) are strong enhancements of received signal power at very high radar frequencies occurring at altitudes between about 80 and 95 km at polar latitudes during summer. These echoes are caused by inhomogeneities in the electron density of the radar Bragg scale within the plasma of the cold summer mesopause region in the presence of negatively charged ice particles. Thus the occurrence of PMSE contains information about mesospheric temperature and water vapour content but also depends on the ionisation due to solar electromagnetic radiation and precipitating high energetic particles. Continuous observations of PMSE have been done on the North-Norwegian island Andøya (69.3°N, 16.0°E) since 1994 using different VHF radars. The PMSE occurrence rate is positively correlated with the geomagnetic Ap index, however not correlated with the solar Lyman α radiation and shows a significant positive trend during the time interval from 1994 until 2012. VHF radar echoes have been observed also during winter times but in the mid mesosphere from about 55 to 85 km altitude. These so called polar mesosphere winter echoes (PMWE) have been observed continuously at Andøya since 2004 using the ALWIN VHF radar (until 2008) and the Middle Atmosphere Alomar Radar System MAARSY (since 2011). Using the more sensitive MAARSY compared to the previous VHF radar systems operated at the site, results in more detections characterized by smaller volume reflectivity values down to 4 ṡ 10‑18m‑1. The end of the winter season is now hard to determine since mesospheric echoes have also been observed below altitudes of 80 km during non winter months, particularly around the end of May, i.e. the beginning of the polar mesospheric summer echo season. These observations indicate that the physical mechanism for creating the lower mesospheric echoes is present during the early summer months as well. We present results from long term observations of polar mesospheric

  20. Contribution to polar albedo from a mesospheric aerosol layer

    NASA Technical Reports Server (NTRS)

    Hummel, J. R.

    1977-01-01

    An examination is made of the impact of a layer of particulate matter, assumed to be ice crystals, on the albedo of the polar region. The model is time dependent, includes the growth of the layer, and incorporates the diffuse nature of radiation reflected from the surface and atmosphere. Although the magnitude of the effect is about an order of magnitude less than previous results, the impact is one of heating instead of cooling. It is also shown that ignoring the diffuse nature of the radiation reflected from the underlying earth-atmosphere system, as has been done in many previous simple models, can result in overestimation of the climatological impact of aerosols in sign and magnitude by a factor of up to 4-6.

  1. How Temperature and Water levels affect Polar Mesospheric Cloud Formation

    NASA Astrophysics Data System (ADS)

    Smith, L. L.; Randall, C. E.; Harvey, V.

    2012-12-01

    Using the Cloud Imaging and Particle Size (CIPS) instrument data, which is part of the Aeronomy in the Mesosphere (AIM) mission, we compare the albedo and ice water content measurements of CIPS with the Navy Operation Global Atmospheric Prediction System - Advanced Level Phyiscs and High Altitude (NOGAPS-ALPHA) temperature and water vapor data in order to derive a greater understanding of cloud formation and physics. We particularly focus on data from June 2007 and July 2007 in this case study because of particular cloud structures and formations during this time period for future studies.

  2. Meteoric smoke in the middle atmosphere: seasonal cycle, composition, and interaction with polar mesospheric clouds

    NASA Astrophysics Data System (ADS)

    Hervig, M. E.; Bardeen, C.; Deaver, L. E.; Gumbel, J.

    2012-12-01

    The Solar Occultation for Ice Experiment (SOFIE) onboard the Aeronomy of Ice in the Mesosphere (AIM) satellite has observed polar mesospheric clouds (PMC) and meteoric smoke in the middle atmosphere since early 2007. Meteoric smoke consists of nanometer sized particles that result from meteoroid ablation products. Smoke is thought to play a role in neutral and ion chemistry, the nucleation of mesospheric ice and stratospheric aerosols, and also serve as a tracer of the global circulation. SOFIE smoke observations indicate a seasonal cycle with reduced smoke abundance during polar summer, and variability in the strength of this seasonal cycle from year-to-year. Smoke modeling studies using a climatological atmosphere indicate that this seasonal cycle is due to transport by the strong pole-to-pole circulation. Model simulations that incorporate meteorological conditions concurrent with SOFIE are used to better understand inter-annual variations in smoke transport and relationships to the global circulation. Multi-wavelength SOFIE observations indicate that PMC particles are a mixture of ice and meteoric smoke (0.02-2% by volume). The results further indicate that the smoke contained in ice is consistent with a composition of magnesiowustite or carbon. Multi-wavelength observations of smoke (in the absence of ice) are used to further examine the composition of meteoric smoke. These results also indicate magnesiowustite or carbon, in addition to olivine or magnetite. The observations are used in conjunction with model studies to examine questions concerning mesospheric ice nucleation and ice-smoke coagulation.

  3. Stratospheric Ozone Changes and Polar Mesospheric Cloud (PMC) Trends Observed in SBUV Data

    NASA Astrophysics Data System (ADS)

    DeLand, M. T.; Thomas, G. E.; Shettle, E. P.; Olivero, J. J.

    2013-12-01

    Polar mesospheric clouds (PMCs) are observed at 80-85 km altitude and high latitudes (typically > 50°) only during summer months. It has been suggested that long-term variations of PMC occurrence frequency and brightness are indicators of global climate change as represented through changes in mesospheric temperature and water vapor. The Solar Backscatter Ultraviolet (SBUV) series of satellite instruments, although designed to measure stratospheric profile and total column ozone, have made global observations of bright PMCs since November 1978. Previous analysis of SBUV data found that long-term variations in PMC brightness and occurrence frequency were anti-correlated with solar activity, and that a positive secular trend was present at most latitudes. The limited database of mesospheric temperature and water vapor data has precluded further determination of the source of this trend. Motivated by recent studies with the LIMA general circulation model [Berger and Lübken 2011], which relate mesospheric temperature trends to changes in stratospheric ozone, we have investigated the use of stratospheric ozone changes as a proxy for changes in mesospheric heating and temperature. The decrease in ozone from 1979 to the mid-1990s leads to a cooler mesosphere, and is thus consistent with the rise in PMC ice water content observed in the SBUV record during this period. Similarly, stratospheric ozone changes are smaller from the mid-1990s to the present, and PMC ice water content trends are also reduced in recent years. We will discuss these results and their implications for both previous (before 1979) and future PMC behavior.

  4. Generation of waves by jet-stream instabilities in winter polar stratosphere/mesosphere

    NASA Astrophysics Data System (ADS)

    Shpynev, B. G.; Churilov, S. M.; Chernigovskaya, M. A.

    2015-12-01

    In the paper we investigate the manifestation of large-scale and middle-scale atmospheric irregularities observed on stratosphere/mesosphere heights. We consider typical patterns of circulation in stratosphere and lower mesosphere which are formed due to a difference of air potential energy between equatorial and polar latitudes, especially in polar night conditions. On the base of ECMWF Era Interim reanalysis data we consider the dynamics of midlatitude winter jet-streams which transfer heat from low latitudes to polar region and which develop due to equator/pole baroclinic instabilities. We consider typical patterns of general circulation in stratosphere/lower mesosphere and reasons for creation of flaky structure of polar stratosphere. Also we analyze conditions that are favorable for splitting of winter circumpolar vortex during sudden stratosphere warming events and role of phase difference tides in this process. The analysis of vertical structure of the stratosphere wind shows the presence of regions with significant shear of horizontal velocity which favors for inducing of shear-layer instability that appears as gravity wave on boundary surface. During powerful sudden stratosphere warming events the main jet-stream can amplify these gravity waves to very high amplitudes that causes wave overturning and releasing of wave energy into the heat due to the cascade breakdown and turbulence. For the dynamics observed in reanalysis data we consider physical mechanisms responsible for observed phenomena.

  5. Study of the mesosphere using wide-field twilight polarization measurements: Early results beyond the polar circle

    NASA Astrophysics Data System (ADS)

    Ugolnikov, O. S.; Kozelov, B. V.

    2016-07-01

    This paper discusses the results of early measurements of temperature and dust in the mesosphere on the basis of wide-field twilight sky polarimetry, which began in 2015 in Apatity (North of Russia, 67.6° N, 33.4° E) using the original entire-sky camera. These measurements have been performed for the first time beyond the Polar Circle in the winter and early spring period. The general polarization properties of the twilight sky and the procedure for identifying single scattering are described. The key results of the study include the Boltzmann temperature values at altitudes higher than 70 km and the conclusion on a weak effect of dust on scattering properties of the mesosphere during this period.

  6. The Nature of Icy Dust Particles in the Polar Summer Mesosphere From Rocket Measurements During DROPPS

    NASA Astrophysics Data System (ADS)

    Goldberg, R. A.; Webb, P. A.; Pesnell, W. D.; Voss, H. D.

    2005-12-01

    The two Black Brant payloads flown during the DROPPS (Distribution and Role of Particles in the Polar Summer Mesosphere) rocket program were launched during early July, 1999 from Andoya Rocket Range (ARR), Norway. Both payloads included front mounted side by side Particle Impact Detector (PID) charge and mass telescopes. Computer simulations have shown that the PID telescopes have the potential to detect atmospheric ice particles within the mesosphere, having dimensions of a few nanometers. Ice particles of nanometer size are believed to be responsible for polar mesospheric summer echoes (PMSEs), such as those observed at an altitude of ~82-87 km over Andoya during the first DROPPS launch sequence. We have previously presented results from the longer PID charge telescope that indicated two possible particle distributions differing by mean particle size. Due to the different geometries of the PID telescopes (primarily, that the charge telescope is longer than the mass telescope) each PID telescope collects a different portion of the nanometer sized PMSE particles distribution. When compared to the previous PID charge telescope results, the PID mass telescope results allow the true PMSE particle size distribution to be estimated. This talk will introduce the new observations from the shorter PID mass telescope and the comparison to the previous PID charge telescope. By then comparing PID observations with the computer simulations provides information concerning the properties of the PMSE particles, including their "rocky" core size, ice mantle thickness and distribution.

  7. First Measurements of Polar Mesospheric Summer Echoes by a Tri-static Radar System

    NASA Astrophysics Data System (ADS)

    La Hoz, C.

    2015-12-01

    Polar Mesospheric Summer Echoes (PMSE) have been observed for the first time by a tri-static radar system comprising the EISCAT VHF (224 MHz, 0.67 m Bragg wavelength) active radar in Tromso (Norway) and passive receiving stations in Kiruna, (Sweden) and Sodankyla (Finland). The antennas at the receiving stations, originally part of the EISCAT tri-static UHF radar system at 930 MHz, have been refitted with new feeder systems at the VHF frequency of the transmitter in Tromso. The refitted radar system opens new opportunities to study PMSE for its own sake and as a tracer of the dynamics of the polar mesosphere, a region that is difficult to investigate by other means. The measurements show that very frequently both remote receiving antennas detect coherent signals that are much greater than the regular incoherent scattering due to thermal electrons and coinciding in time and space with PMSE measured by the transmitter station in Tromso. This represents further evidence that PMSE is not aspect sensitive, as was already indicated by a less sensitive radar system in a bi-static configuration, and implying that the underlying atmospheric turbulence, at least at sub-meter scales, is isotropic in agreement with Kolmogorov's hypothesis. Measurements also show that the vertical rate of fall of persistent features of PMSE is the same as the vertical line of sight velocity inferred from the doppler shift of the PMSE signals. This equivalence forms the basis for using PMSE as a tracer of the dynamics of the background mesosphere. Thus, it is possible to measure the 3-dimensional velocity field in the PMSE layer over the intersection volume of the three antennas. Since the signals have large signal-to-noise ratios (up to 30 dB), the inferred velocities have high accuracies and good time resolutions. This affords the possibility to make estimates of momentum flux in the mesosphere deposited by overturning gravity waves. Gravity wave momentum flux is believed to be the engine of a

  8. Highlights of the MaCWAVE program to study the polar mesosphere

    NASA Astrophysics Data System (ADS)

    Goldberg, R. A.; Fritts, D. C.

    MaCWAVE M ountain A nd C onvective W aves A scending Ve rtically was a highly coordinated rocket ground-based and satellite program designed to address gravity wave forcing of the mesosphere and lower thermosphere MLT The MaCWAVE program was conducted at the Norwegian And o ya Rocket Range ARR 69 3 r N in July 2002 and continued at the Swedish Rocket Range ESRANGE 67 9 r N during January 2003 Correlative instrumentation included the ALOMAR MF and MST radars and RMR and Na lidars ESRANGE MST and meteor radars and RMR lidar radiosondes and TIMED satellite measurements of thermal and constituent structures The data have been used to define the wave field structure fluxes and turbulence generation leading to forcing of the large-scale flow down to a description of small-scale turbulence In summer launch sequences coupled with ground-based measurements at ARR addressed the forcing of the summer mesopause environment by anticipated convective and shear generated gravity waves The summer program demonstrated that the mean state of the upper mesosphere was unusually warm slowing the formation of Polar Mesospheric Summer echoes PMSE and noctilucent clouds NLC The winter program was designed to study the upward propagation and penetration of mountain waves from northern Norway into the MLT at a site favored for such penetration As the major response was expected to be downstream east of Norway these motions were measured with rocket sequences and ground-based instrumentation

  9. Polar Cap Disturbances: Mesosphere and Thermosphere-Ionosphere Response to Solar-Terrestrial Interactions

    NASA Technical Reports Server (NTRS)

    Sivjee, G.; McEwen, D.; Walterscheid, R.

    2003-01-01

    The Polar Cap is the Upper-Atmosphere cum Mag-netosphere region which is enclosed by the poleward boundary of the Auroral Oval and is threaded by open geomagnetic tield lines. In this region, there is normally a steady precipition (Polar "drizzle") of low energy (w 300eV) electrons that excite optical emissions from the ionosphere. At times, enhanced ionization patches are formed near the Dayside Cusp regions that drift across the Polar Cap towards the Night Sector of the Auroral Oval. Discrete auroral arcs and auroras formed during Solar Magnetic Cloud (SMC)/Coronal Mass Ejection (CME) events are also observed in the Polar Cap. Spectrophotometric observations of all these Polar Cap phenomena provide a measure of the average energy as well a energy flux of the electrons precipitating in the Polar Cap region during these disturbances. Such measurements also point to modulations of the Polar Cap Mesosphere-Lower Thermosphere (MLT) air density and temperature by zonally symmetric tides whose Hough functions peak in the Polar region. MLT cooling during Stratospheric Warming events and their relation to Polar Vortex and associated Gravity wave activities are also observed at the Polar Cap sites.

  10. Water Vapor, Temperature, and Ice Particles in Polar Mesosphere as Measured by SABER/TIMED and OSIRIS/Odin Instruments

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Petelina, S. V.; Kutepov, A. A.; Pesnell, W. D.; Goldberg, R. A.

    2009-01-01

    Although many new details on the properties of mesospheric ice particles that farm Polar Mesospheric Clouds (PMCs) and also cause polar mesospheric summer echoes have been recently revealed, certain aspects of mesospheric ice microphysics and dynamics still remain open. The detailed relation between PMC parameters and properties of their environment, as well as interseasonal and interhemispheric differences and trends in PMC properties that are possibly related to global change, are among those open questions. In this work, mesospheric temperature and water vapor concentration measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite are used to study the properties of PMCs with respect to the surrounding atmosphere. The cloud parameters, namely location, brightness, and altitude, are obtained from the observations made by the Optical Spectrograph and Infrared Imager System (OSIRIS) on the Odin satellite. About a thousand of simultaneous common volume measurements made by SABER and OSIRIS in both hemispheres from 2002 until 2008 are used. The correlation between PMC brightness (and occurrence rate) and temperatures at PMC altitudes and at the mesopause is analysed. The relation between PMC parameters, frost point temperature, and gaseous water vapor content in and below the cloud is also discussed. Interseasonal and interhemispheric differences and trends in the above parameters, as well as in PMC peak altitudes and mesopause altitudes are evaluated.

  11. Assymetry in the Polar Mesosphere Revealed by the 2012 Venus Transit Aureole

    NASA Astrophysics Data System (ADS)

    Widemann, Thomas; Tanga, P.; Reardon, K. P.; Limaye, S.; Wilson, C.; Vandaele, A.; Wilquet, V.; Mahieux, A.; Robert, S.; Pasachoff, J. M.; Schneider, G.

    2012-10-01

    Close to ingress and egress phases, the fraction of Venus disk projected outside the solar photosphere appears outlined by an irregular thin arc of light called the "aureole." We have shown that the deviation due to refraction and the aureole intensity are related to the local density scale height and the altitude of the refraction layer (Tanga et al. 2012). Since the aureole brightness is the quantity that can be measured during the transit, an appropriate model allows us to determine both parameters. We now compare this model developed for the 2004 data to the first results of 2012 campaign. Ingress pictures of NASA's SDO/HMI observations, OP-OCA/VTE coronagraph observations at Haleakala and Lowell stations, and Dunn/IBIS observations at Sacramento Peak, NM, show latitudinal structure of the aureole during the ingress phase of the Venus transit. For the HMI data, the temporal cadence is 3.75 sec and the pixel scale is 0.5 arcsec/pixel. The polar region, significantly brighter in initial phases due to the larger scale height of the polar mesosphere, appears consistently offset toward morning terminator by about 15 deg. latitude, peaking at 75N at 6:00 local time. This result reflects local latitudinal structure in the polar mesosphere, either in temperature or aerosol altitude distribution. Relation with ESA / Venus Express / SOIR simultaneous measurements and dynamical interpretation will be discussed at the meeting. Tanga et al. 2012, Icarus 218, 207-219

  12. Enhancement of Thomson scatter by charged aerosols in the polar mesosphere - Measurements with a 1.29-GHz radar

    NASA Technical Reports Server (NTRS)

    Cho, John Y. N.; Kelley, Michael C.; Heinselman, Craig J.

    1992-01-01

    The summer polar mesosphere was observed with the Sondrestrom 1.29-GHz radar with a new high-resolution data acquisition mode. On one occasion, a spatially narrow enhancement in the backscattered power was seen near an altitude of 88 km. Possible explanations are discussed and it is proposed that this layer may be the first example of polar mesosphere summer echoes detected above 1 GHz. Specifically, suggested that these echoes are enhanced Thomson scatter from a layer of charged aerosols, and speculate on the size and charge state.

  13. Effect of Gravity Waves Generated in the Monsoon Region on Polar Mesospheric Clouds

    NASA Astrophysics Data System (ADS)

    Thurairajah, B.; Bailey, S. M.; Carstens, J. N.; Siskind, D. E.

    2015-12-01

    Gravity Waves (GWs) play an important role in both the formation and destruction of polar mesospheric clouds. In summer, while vertically propagating GWs induce a residual circulation that cools the summer mesosphere and therefore supports the formation of PMCs, observation and modeling studies have also shown that short period GWs can additionally destroy PMCs. In this study we analyze the effect of non-vertical propagation of GWs on PMCs using temperature data from the SABER instrument on TIMED satellite and PMC occurrence frequency from the CIPS instrument on the AIM satellite. During the 2007 PMC season, time series of GWs over the monsoon region at 50 km and PMCs over the polar region at 84 km have a correlation coefficient of 0.9. SABER GW amplitude and momentum flux over the monsoon region show a poleward tilt with altitude. This slanted structure suggests a poleward, but non-vertical, propagation of GWs facilitated by the easterly winds associated with the monsoon circulation, thus indicating a possible source of high latitude middle atmospheric GWs.

  14. Polar Mesospheric Cloud North/South Hemispheric differences: from SME (1982- present

    NASA Astrophysics Data System (ADS)

    Thomas, G. E.; DeLand, M. T.; Shettle, E. P.

    2011-12-01

    The Ultraviolet Spectrometer (UVS) on the Solar Mesosphere Explorer (SME) mission (1981-86) was designed to measure mesospheric ozone by limb sounding at pairs of UV wavelengths, and to establish its relationship with changes in solar spectral irradiance made by an accompanying solar experiment (Rottman, G. , this meeting). Because of its near-polar sun-synchronous orbit, it was anticipated that the overflights of the polar regions (up to 82 deg) would yield new information on transpolar mesospheric clouds, discovered earlier in 1969 by Donahue and colleagues. Known at lower latitudes as noctilucent clouds (NLC), the extensive ice layer was found in 1969 to grow in scattered brightness and occurrence frequency with latitude. SME was launched at a time when very little was known about the ice properties, their seasonal morphology, north/south differences, etc. SME in its five year lifetime over which atmospheric measurements were made established for the first time the seasonal morphology in the period (1981-86), constrained the particle sizes, described north/south differences, etc. The term PMC originated in the first publication of SME cloud data (Thomas, 1984). This paper describes the SME PMC data base, which has been updated extensively since the first publications. Its focus is on the question of north/south differences in PMC properties, and whether these properties have changed over the 30-year period from the SME era to the present. The quantity of interest is the north/south ratio (NSR) of ice water mass (IWC). The NSR has been reported to be greater than two, on the average, using Solar Backscatter Ultraviolet Spectrometer (SBUV) data by Stevens et al (2007). This earlier study applied to the years of the SME mission, and so provide a good comparison to the present results, with two differences: (1) we deal with the more sensitive SME data and thus a greater fraction of the IWC, and (2) use a new regression analysis which relates IWC to the scattered

  15. Polar Mesospheric Clouds (PMCs) Observed by the Ozone Monitoring Instrument (OMI) on Aura

    NASA Technical Reports Server (NTRS)

    DeLand, Matthew T.; Shettle, Eric P.; Levelt, Pieternel F.; Kowalewski, Matthew G.

    2010-01-01

    Backscattered ultraviolet (BUV) instruments designed for measuring stratospheric ozone profiles have proven to be robust tools for observing polar mesospheric clouds (PMCs). These measurements are available for more than 30 years, and have been used to demonstrate the existence of long-term variations in PMC occurrence frequency and brightness. The Ozone Monitoring Instrument (OMI) on the EOS Aura satellite provides new and improved capabilities for PMC characterization. OMI uses smaller pixels than previous BUV instruments, which increases its ability to identify PMCs and discern more spatial structure, and its wide cross-track viewing swath provides full polar coverage up to 90 latitude every day in both hemispheres. This cross-track coverage allows the evolution of PMC regions to be followed over several consecutive orbits. Localized PMC variations determined from OMI measurements are consistent with coincident SBUV/2 measurements. Nine seasons of PMC observations from OMI are now available, and clearly demonstrate the advantages of these measurements for PMC analysis.

  16. Extreme stratospheric springs and their consequences for the onset of polar mesospheric clouds

    NASA Astrophysics Data System (ADS)

    Siskind, David E.; Allen, Douglas R.; Randall, Cora E.; Harvey, V. Lynn; Hervig, Mark E.; Lumpe, Jerry; Thurairajah, Brentha; Bailey, Scott M.; Russell, James M.

    2015-09-01

    We use data from the Aeronomy of Ice in the Mesosphere (AIM) explorer and from the NASA Modern Era Retrospective Analysis for Research and Applications (MERRA) stratospheric analysis to explore the variability in the onset of the Northern Hemisphere (NH) Polar Mesospheric Cloud (PMC) season. Consistent with recently published results, we show that the early onset of the NH PMC season in 2013 was accompanied by a warm springtime stratosphere; conversely, we show that the late onset in 2008 coincides with a very cold springtime stratosphere. Similar stratospheric temperature anomalies for 1997 and 2011 also are connected either directly, through observed temperatures, or indirectly, through an early PMC onset, to conditions near the mesopause. These 4 years, 2008, 1997, 2011, and 2013 represent the extremes of stratospheric springtime temperatures seen in the MERRA analysis and correspond to analogous extrema in planetary wave activity. The three years with enhanced planetary wave activity (1997, 2011 and 2013) are shown to coincide with the recently identified stratospheric Frozen In Anticyclone (FrIAC) phenomenon. FrIACs in 1997 and 2013 are associated with early PMC onsets; however, the dramatic FrIAC of 2011 is not. This may be because the 2011 FrIAC occurred too early in the spring. The link between NH PMC onset and stratospheric FrIAC occurrences represents a new mode of coupling between the stratosphere and mesosphere. Since FrIACs appear to be more frequent in recent years, we speculate that as a result, PMCs may occur earlier as well. Finally we compare the zonal mean zonal winds and observed gravity wave activity for the FrIACs of 2011 and 2013. We find no evidence that gravity wave activity was favored in 2013 relative to 2011, thus suggesting that direct forcing by planetary waves was the key mechanism in accelerating the cooling and moistening of the NH mesopause region in May of 2013.

  17. Gravity waves in polar mesospheric clouds measured by Odin/OSIRIS since 2002

    NASA Astrophysics Data System (ADS)

    Petelina, S. V.

    2009-05-01

    The Optical Spectrograph and InfraRed Imager System instrument (OSIRIS) on the limb-viewing Odin satellite observes Polar Mesospheric Clouds (PMCs) in both hemispheres since November, 2001. The orbit period of Odin is 96 minutes and the maximum latitudinal coverage in the orbit plane is between 82.2 N and 82.2 S. In this work, the longitudinal distribution of Odin/OSIRIS PMC brightness in each hemisphere during a 4-week period around the summer solstice from 2002 until 2009 is analyzed. It is found that in the southern hemisphere, the cloud brightness was consistently up to 30% lower around 250-300°E (70-120°W) - above the Antarctic peninsular. In the northern hemisphere, the PMC brightness was systematically 20-30% lower around 50-130°E - above Ural Mountains. Similar results have been obtained for the PMC 2007-08 season in Antarctica and PMC-2007 Arctic season by one of the instruments on a recently launched Aeronomy of Ice in the Mesosphere (AIM) satellite. We attribute this effect to the influence of gravity waves generated by the Earth's terrain.

  18. Numerical simulations of the three-dimensional distribution of polar mesospheric clouds using WACCM/CARMA

    NASA Astrophysics Data System (ADS)

    Bardeen, C. G.; Toon, O. B.; Jensen, E. J.; Benze, S.; Marsh, D. R.; Randall, C. E.; Merkel, A. W.

    2007-12-01

    Polar mesospheric clouds (PMC) are ice clouds that routinely form in the cold summer mesopause region; however, the nucleation mechanism for these clouds is not well understood. Several possible condensation nuclei have been identified including: meteoric dust, ion clusters, sulfate aerosols, soot, sodium bicarbonate and sodium hydroxide. Recent studies have shown that fewer large meteoric dust particles may be present in the summer mesopause region than have previously been assumed to be necessary for the nucleation of PMCs. We use WACCM/CARMA, a three-dimensional chemistry climate model based upon the Whole-Atmosphere Community Climate Model (WACCM) with sectional microphysics from the Community Aerosol and Radiation Model for Atmospheres (CARMA) to study the distribution and characteristics of PMCs formed by heterogeneous nucleation with meteoric dust particles. The distribution of meteoric dust particles in the model is also calculated using sectional microphysics and is based upon a source of recondensed material from the ablation of micrometeoroids. Results from these simulations are compared with several observations including those from the Aeronomy of Ice in the Mesosphere (AIM) mission, the Solar Backscatter Ultraviolet (SBUV) instrument and the Student Nitric Oxide Explorer (SNOE) satellite and with results from other models.

  19. Mesospheric Temperatures and Meteoric Dust Detection based on Wide-angle Polarization Measurements of the Twilight Sky

    NASA Astrophysics Data System (ADS)

    Ugolnikov, Oleg; Maslov, Igor

    The work is based on fast all-sky polarization measurements of the twilight background started in 2011 in central Russia (55.2 deg N, 37.5 deg E). The data is used to build the polarization scattering functions of the mesospheric medium depending on the altitude. These functions can be used for dust scattering detection and study. The problem is hard to be solved by space or lidar measurements providing the data just for one definite scattering angle, however, the twilight technique is the least expensive method for the mesospheric research. The method described in (Ugolnikov, Maslov, 2013) is used to separate single and multiple scattering, which is the basic problem of the twilight remote sensing. Light scattering in the mesosphere is turned out to be Rayleigh-dominated for the most part of observation dates. This allows finding the altitude dependencies of pressure and the temperatures in the mesosphere. The values of temperature are in good agreement with TIMED/SABER and EOS Aura/MLS space limb data for nearby locations. Admixture of dust scattering was occasionally observed, reaching the maximum during the Perseids meteor shower activity in 2013. The scattering functions analysis gives the value of moderated dust layer in the mesosphere (81-83 km) and helps to estimate the particles size. The work is supported by Russian Foundation for Basic Research, grant 12-05-00501-a. References Ugolnikov O.S., Maslov I.A. Summer mesosphere temperature distribution from wide-angle polarization measurements of the twilight sky // Journal of Atmospheric and Solar-Terrestrial Physics, V.105-106, P.8-14, 2013.

  20. On the angular dependence and scattering model of polar mesospheric summer echoes at VHF

    NASA Astrophysics Data System (ADS)

    Sommer, Svenja; Stober, Gunter; Chau, Jorge L.

    2016-01-01

    We present measurements of the angular dependence of polar mesospheric summer echoes (PMSE) with the Middle Atmosphere Alomar Radar System in Northern Norway (69.30° N, 16.04° E). Our results are based on multireceiver and multibeam observations using beam pointing directions with off-zenith angles up to 25° as well as on spatial correlation analysis (SCA) from vertical beam observations. We consider a beam filling effect at the upper and lower boundaries of PMSE in tilted beams, which determines the effective mean angle of arrival. Comparing the average power of the vertical beam to the oblique beams suggests that PMSE are mainly not as aspect sensitive as in contrast to previous studies. However, from SCA, times of enhanced correlation are found, indicating aspect sensitivity or a localized scattering mechanism. Our results suggest that PMSE consist of nonhomogeneous isotropic scattering and previously reported aspect sensitivity values might have been influenced by the inhomogeneous nature of PMSE.

  1. Studies of Polar Mesosphere Summer Echoes by VHF radar and rocket probes

    NASA Technical Reports Server (NTRS)

    Hoppe, U. -P.; Blix, T. A.; Thrane, E. V.; Lubken, F. -J.; Cho, J. Y. N.; Swartz, W. E.

    1994-01-01

    At radar frequencies in the range 50 MHz to 250 MHz, at times even to over 1 GHz, strong enhancements of scattering cross section occur between approximately equal to 80 km and approximately 95 km altitude in summer at high latitudes. These echoes, termed 'Polar Mesosphere Summer Echoes' (PMSE) have attracted considerable experimental effort. Observations of this phenomenon are reviewed in the context of atmospheric dynamics and of scattering processes. Recent rocket and radar measurements indicate that a partial reflection from a multitude of ion layers and constructive interference causes at least some of the PMSE. It is discussed which further observations are necessary and some possible practical consequences of PMSE are pointed out.

  2. The importance of ice particle shape on UV measurements of polar mesospheric clouds: SBUV/2 observations

    NASA Astrophysics Data System (ADS)

    Baumgarten, Gerd; Thomas, Gary E.

    2006-01-01

    We present calculations of scattering of solar UV radiation from polar mesospheric clouds (PMC) for the wavelengths and scattering angles appropriate to the SBUV/2 series of satellite experiments. Our model includes for the first time the effects of non-sphericity of ice particles whose evidence has been recently gained from lidar depolarization experiments. Our results apply to the scattering cross section averaged over a particle size ensemble which spans the mean size and size ranges expected for PMC. We demonstrate that for the size range 20 100 nm (effective spherical particle radius), the wavelength range 252 292 nm, and the scattering angle range 100 140, non-spherical particles cause only moderate (<35%) deviations from conventional Mie theory, which assumes spherical shapes. The total UV scattering efficiency of PMC particles per unit mass of water vapor is not significantly affected by shape effects, in the range of parameters studied. On the other hand, our study suggests that shape effects need to be considered in the analysis of UV spectra of PMC, such as those of Carbary et al. [2004. Evidence for bimodal particle distribution from the spectra of polar mesospheric clouds. Geophysical Research Letters 31 (13), 3108] and DeLand et al. [2005. Spectral measurements of PMCs from SBUV/2 instruments. Journal of Atmospheric and Solar-Terrestrial Physics, to appear, doi: 10.1016/j.astp.2005.08.006]. In particular, attention must also be paid to the scattering angle dependence of the measurements, and the range of scattering angles involved in compiling average spectra of PMC.

  3. Solar-induced 27-day variations of mesospheric temperature and water vapor from the AIM SOFIE experiment: Drivers of polar mesospheric cloud variability

    NASA Astrophysics Data System (ADS)

    Thomas, Gary E.; Thurairajah, Brentha; Hervig, Mark E.; von Savigny, Christian; Snow, Martin

    2015-11-01

    Polar Mesospheric Clouds (PMCs) are known to be influenced by changes in water vapor and temperature in the cold summertime mesopause. Solar variability of these constituents has been held responsible for 11-year and 27-day variability of PMC activity, although the detailed mechanisms are not yet understood. It is also known that the solar influence on PMC variability is a minor contributor to the overall day-to-day variability, which is dominated by effects of gravity waves, planetary waves, and inter-hemispheric coupling. To address this issue, we have analyzed 15 seasons of data taken from the Solar Occultation for Ice Experiment (SOFIE) on the Aeronomy of Ice in the Mesosphere (AIM) satellite. The SOFIE data contain precise measurements of water vapor, temperature and ice water content (among other quantities). These high-latitude measurements are made during the PMC season at the terminator, and therefore directly relate to the simultaneous measurements of mesospheric ice. Using a composite data set of Lyman-α irradiance, we correlated the time variation of the atmospheric variables with the 27-day variability of solar ultraviolet irradiance. We used a combination of time-lagged linear regression and Superposed Epoch Analysis to extract the solar contribution as sensitivity values (response/forcing) vs. height. We compare these results to previously published results, and show that the temperature sensitivity is somewhat higher, whereas the water sensitivity is nearly the same as published values. The time lags are shorter than that expected from direct solar heating and photodissociation, suggesting that the responses are due to 27-day variations of vertical winds. An analytic solution for temperature changes forced by solar irradiance variations suggests that if the response is due purely to Lyman-α heating and Newtonian cooling, the response should vary throughout the summertime season and depend primarily upon the height-dependent column density of

  4. What can be learned about Polar Mesospheric Clouds from suborbital missions?

    NASA Astrophysics Data System (ADS)

    Thomas, G. E.; McClintock, W.; Fritts, D. C.

    2011-12-01

    Noctilucent clouds ('night luminous' or NLC) are the highest and coldest clouds in the atmosphere. When viewed from the ground they are referred to as NLC. Viewed from space they are called Polar Mesospheric Clouds, or PMC. Occupying a narrow (81-86 km) height zone below the high-latitude mesopause (a temperature minimum versus height, located near 88 km), NLC offer a splendid sight during summer twilights. They are made visible by scattered sunlight against the dark twilight sky, when the sun lies below the horizon at angles between 6o and 16o. The state of the science has been advanced significantly since the launches of the Odin and Aeronomy of Ice in the Mesosphere (AIM) satellite missions. The spatial scales of the clouds are evident in the Cloud Imaging and Particle Size (CIPS) experiment down to its limiting resolution of 5 km. However, from ground-based photography of NLC, and from theoretical modeling of small-scale 3D instability and turbulence dynamics in the upper mesosphere, we know that there is much structure on the sub-km scale which is yet to be explored. Turbulent breakdown is expected to occur in this sub-km range. Fortunately, on the short-time scales of turbulence, ice particles should act as passive tracers, which are advected by the wind field. Sub-orbital missions provide an ideal observing platform for extending the PMC 'spatial spectrum' ranging currently from hundreds to tens of km (which we now know from CIPS) down to tens of meters, a 'leap' of three orders of magnitude. A high resolution camera with a CMOS chip, is easily capable of sub-km resolution, with S/N ratios exceeding 100 for a bright PMC. A wide (150 nm) bandpass centered on the blue portion of the PMC spectrum isolates the most intense portion of the scattered brightness. Movies of the clouds as the sub-orbital vehicle approaches, and penetrates the cloud, would be valuable, both for the scientific goal of studying the 'transition to turbulence', but also for educational

  5. Thermodynamics of polarized relativistic matter

    NASA Astrophysics Data System (ADS)

    Kovtun, Pavel

    2016-07-01

    We give the free energy of equilibrium relativistic matter subject to external gravitational and electromagnetic fields, to one-derivative order in the gradients of the external fields. The free energy allows for a straightforward derivation of bound currents and bound momenta in equilibrium. At leading order, the energy-momentum tensor admits a simple expression in terms of the polarization tensor. Beyond the leading order, electric and magnetic polarization vectors are intrinsically ambiguous. The physical effects of polarization, such as the correlation between the magneto-vortically induced surface charge and the electro-vortically induced surface current, are not ambiguous.

  6. Polar summer mesospheric extreme horizontal drift speeds during interplanetary corotating interaction regions (CIRs) and high-speed solar wind streams: Coupling between the solar wind and the mesosphere

    NASA Astrophysics Data System (ADS)

    Lee, Young-Sook; Kirkwood, Sheila; Kwak, Young-Sil; Kim, Kyung-Chan; Shepherd, Gordon G.

    2014-05-01

    We report the observation of echo extreme horizontal drift speed (EEHS, ≥ 300 m s-1) during polar mesospheric (80-90 km) summer echoes (PMSEs) by the VHF (52 MHz) radar at Esrange, Sweden, in years of 2006 and 2008. The EEHS occur in PMSEs as correlated with high-speed solar wind streams (HSSs), observed at least once in 12-17% of all hours of observation for the two summers. The EEHS rate peaks occur either during high solar wind speed in the early part of the PMSE season or during the arrival of interplanetary corotating interaction regions (CIRs) followed by peaks in PMSE occurrence rate after 1-4 days, in the latter part of the 2006 summer. The cause of EEHS rate peaks is likely under the competition between the interval of the CIR and HSS passage over the magnetosphere. A candidate process in producing EEHS is suggested to be localized strong electric field, which is caused by solar wind energy transfer from the interaction of CIR and HSS with the magnetosphere in a sequential manner. We suggest that EEHS are created by strong electric field, estimated as > 10-30 V m-1 at 85 km altitude, exceeding the mesospheric breakdown threshold field.

  7. 27-day solar forcing of mesospheric temperature, water vapor and polar mesospheric clouds from the AIM SOFIE and CIPS satellite experiments

    NASA Astrophysics Data System (ADS)

    Thomas, Gary; Thurairajah, Brentha; von Savigny, Christian; Hervig, Mark; Snow, Martin

    2016-04-01

    Solar cycle variations of ultraviolet radiation have been implicated in the 11-year and 27-day variations of Polar Mesospheric Cloud (PMC) properties. Both of these variations have been attributed to variable solar ultraviolet heating and photolysis, but no definitive studies of the mechanisms are available. The solar forcing issue is critical toward answering the broader question of whether PMC's have undergone long-term changes, and if so, what is the nature of the responsible long-term climate forcings? One of the principal goals of the Aeronomy of Ice in the Mesosphere satellite mission was to answer the question: "How does changing solar irradiance affect PMCs and the environment in which they form?" We describe an eight-year data set from the AIM Solar Occultation for Ice Experiment (SOFIE) and the AIM Cloud Imaging and Particle Size (CIPS) experiment. Together, these instruments provide high-precision measurements of high-latitude summertime temperature (T), water vapor (H2O), and PMC ice properties for the period 2007-present. The complete temporal coverage of the summertime polar cap region for both the primary atmospheric forcings of PMC (T and H2O), together with a continually updated time series of Lyman-alpha solar irradiance, allows an in-depth study of the causes and effects of 27-day PMC variability. The small responses of these variables, relative to larger day-to-day changes from gravity waves, tides, inter-hemispheric coupling, etc. require a careful statistical analysis to isolate the solar influence. We present results for the 27-day responses of T, H2O and PMC for a total of 15 PMC seasons, (30 days before summer solstice to 60 days afterward, for both hemispheres). We find that the amplitudes and phase relationships are not consistent with the expected mechanisms of solar UV heating and photolysis - instead we postulate a primarily dynamical response, in which a periodic vertical wind heats/cools the upper mesosphere, and modulates PMC

  8. First SuperDARN polar mesosphere summer echoes observed at SANAE IV, Antarctica

    NASA Astrophysics Data System (ADS)

    Ogunjobi, Olakunle; Sivakumar, Venkataraman; Judy; Stephenson, A. E.

    For over 3 decades studies on Polar mesosphere summer echo (PMSE) is ongoing. Its causative mechanism in the Antarctic and Arctic mesopause altitude is yet to be completely understood and is partly due to few observations from Antarctica. Also important were the varied influencing factors across the observable locations. For the first time, we report the PMSE occurrence probability rates over South African National Antarctic Expedition IV (SANAE IV). A comparison is made with observation from SANAE IV magnetic conjugate vicinity, Goose Bay in Arctic region. Here, a new matching coincidence method allowing filtration of possible contaminating echoes is described and implemented for extraction of PMSE during the 2005-2007 summers. In this method, Riometer and Super Dual Auroral Radar Network (SuperDARN) measurements from SANAE IV location are matched to obtain PMSE occurrence probability rate. Whereas the seasonal and diurnal variations followed the known features of PMSE, the percentage difference in probability occurrence rate is found to be remarkable. The SANAE IV probability rate is found to be high for the summer months reaching about 50% peak around the summer solstice. When the coincidence algorithm is relaxed, we found a substantial 30% increase in PMSE occurrence rate at SANAE IV. At this time, about 100% peak is found for Goose Bay. The contribution from the ionospheric D region electron density enhancements to SuperDARN PMSE occurrence rates at locations under auroral regions will be presented.

  9. Polar Mesospheric Cloud Occurrence from Geostationary Satellite Observations in the Northern Hemisphere for the Period 2001 to 2005

    NASA Astrophysics Data System (ADS)

    Delaney, C.; Jennings, S. G.; Rodaighe, A.

    2012-04-01

    Polar Mesospheric Clouds (PMC) are the highest clouds in the atmosphere occurring over the summer polar regions at around 83 km in the Mesosphere. Since their discovery in 1885, they have attracted much research and recently they have attracted attention as possible indicators of Climate Change. In the past, their height and optical thinness restricted the opportunities for observation of PMC; however the development of remote sensing satellites has provided a consistent method of observing them in the Mesosphere. Observations of PMC have been made from both numerous polar orbiting satellites and the European geostationary weather satellites (METEOSAT). METEOSAT observations of PMC are in the visible band of the high resolution radiometer (MVIRI) of the first generation weather satellite; they have a greater spatial extent per observation at a higher frequency rate than those of polar orbiting platforms. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) maintains an archive of METEOSAT observations. By building a suitable data management and image analysis infrastructure, we were able to use the archive to make PMC observations in the stored visible band imagery. The design and development of the system (PMC-Explorer) and details of dealing with EUMETSAT data formats are described. PMC occurrence frequencies for the Northern Hemisphere summers are presented for years 2001 to 2005. The seasonal properties are presented, inter-annual comparisons are made and five year seasonal means are calculated and compared with the 1995 season. A comparison with similar published data from polar orbiting satellites is made. An increase PMC in observations between 2001 and 2005 is presented. The potential impact of Climate Change on the occurrence frequency of PMC is discussed. Finally, suggestions are made on further uses of the EUMETSAT archive for PMC research and the potential of comparisons with other remote sensing platforms.

  10. The roles of temperature and water vapor at different stages of the polar mesospheric cloud season

    NASA Astrophysics Data System (ADS)

    Rong, P. P.; Russell, J. M., III; Hervig, M. E.; Bailey, S. M.

    2012-02-01

    Temperature, or alternatively, saturation vapor pressure (PSAT), dominantly controls the polar mesospheric cloud (PMC) seasonal onset and termination, characterized by a strong anticorrelated relationship between the Solar Occultation for Ice Experiment (SOFIE)-observed PMC frequency and PSAT on intraseasonal time scales. SOFIE is highly sensitive to weak clouds and can obtain a nearly full spectrum of PMCs. Both the SOFIE PMC frequency and PSAT indicate a rapid onset and termination of the season. Compared to PSAT, the water vapor partial pressure (PH2O) exhibits only a slight increase from before to after the start of the season. We are able to use the PSAT daily minimum and two averaged PH2O levels taken before and after the solstice, respectively, to estimate the start and end days of the PMC season within 1-2 days uncertainty. SOFIE ice mass density and its relationship to PH2O and PSAT are examined on intraseasonal scales and for two extreme conditions, i.e., strong and weak cloud cases. In the strong cloud case, such as those bright clouds that occur during the core of the season, PH2O far exceeds PSAT and dominantly controls the ice mass density variation, while in the weak cloud case, such as those clouds that occur at the start and end of the season, PH2O and PSAThave comparable magnitudes, vary in concert, and have similar effects on the ice mass density variation. These results suggest that the long-term brightness trends reported by DeLand et al. (2007) are primarily driven by changes in water vapor (H2O), not temperature.

  11. Measurements of global distributions of polar mesospheric clouds during 2005-2012 by MIPAS/Envisat

    NASA Astrophysics Data System (ADS)

    García-Comas, Maya; López-Puertas, Manuel; Funke, Bernd; Aythami Jurado-Navarro, Á.; Gardini, Angela; Stiller, Gabriele P.; von Clarmann, Thomas; Höpfner, Michael

    2016-06-01

    We have analysed MIPAS (Michelson Interferometer for Passive Atmopheric Sounding) infrared measurements of PMCs for the summer seasons in the Northern (NH) and Southern (SH) hemispheres from 2005 to 2012. Measurements of PMCs using this technique are very useful because they are sensitive to the total ice volume and independent of particle size. For the first time, MIPAS has provided coverage of the PMC total ice volume from midlatitudes to the poles. MIPAS measurements indicate the existence of a continuous layer of mesospheric ice, extending from about ˜ 81 km up to about 88-89 km on average and from the poles to about 50-60° in each hemisphere, increasing in concentration with proximity to the poles. We have found that the ice concentration is larger in the Northern Hemisphere than in the Southern Hemisphere. The ratio between the ice water content (IWC) in both hemispheres is also latitude-dependent, varying from a NH / SH ratio of 1.4 close to the poles to a factor of 2.1 around 60°. This also implies that PMCs extend to lower latitudes in the NH. A very clear feature of the MIPAS observations is that PMCs tend to be at higher altitudes with increasing distance from the polar region (in both hemispheres), particularly equatorwards of 70°, and that they are about 1 km higher in the SH than in the NH. The difference between the mean altitude of the PMC layer and the mesopause altitude increases towards the poles and is larger in the NH than in the SH. The PMC layers are denser and wider when the frost-point temperature occurs at lower altitudes. The layered water vapour structure caused by sequestration and sublimation of PMCs is present at latitudes northwards of 70° N and more pronounced towards the pole. Finally, MIPAS observations have also shown a clear impact of the migrating diurnal tide on the diurnal variation of the PMC volume ice density.

  12. Simultaneous Retrievals of Polar Mesospheric Clouds (PMCs) with Ozone from OMI UV measurements

    NASA Astrophysics Data System (ADS)

    Bak, J.; Liu, X.; Kim, J. H.; Deland, M. T.; Chance, K.

    2015-09-01

    The presence of polar mesospheric clouds (PMCs) at high latitudes could affect the retrieval of ozone profiles using backscattered ultraviolet (BUV) measurements. PMC-induced errors in ozone profile retrievals from Ozone Monitoring Instrument (OMI) BUV measurements are investigated through comparisons with Microwave Limb Sounder (MLS) ozone measurements. This comparison demonstrates that the presence of PMCs leads to systematic biases at altitudes above 6 hPa in summer high latitudes; the biases increase from ~ -2 % at 2 hPa to ~ -20 % at 0.5 hPa on average, and are significantly correlated with brightness of PMCs. Sensitivity studies show that the radiance sensitivity to PMCs strongly depends on wavelengths, increasing by a factor of ~ 4 from 300 to 265 nm. It also strongly depends on the PMC scattering, thus depending on viewing geometry. The optimal estimation-based retrieval sensitivity analysis shows that PMCs located at 80-85 km have the greatest effect on ozone retrievals at ~ 0.2 hPa (~ 60 km), where the retrieval errors range from -2.5 % with PMC optical depth (POD) of 10-4 to -20 % with 10-3 at back scattering angles, and the impacts increase by a factor of ~ 5 at forward scattering angles due to stronger PMC sensitivities. To reduce the interference of PMCs on ozone retrievals, we perform simultaneous retrievals of POD and ozone with a loose constraint of 10-3 for POD, which results in retrieval errors of 1-4 × 10-4. It is demonstrated that the negative bias of OMI ozone retrievals relative to MLS could be improved by including the PMC in the forward model calculation and retrieval.

  13. High-speed solar wind streams and polar mesosphere winter echoes at Troll, Antarctica

    NASA Astrophysics Data System (ADS)

    Kirkwood, S.; Osepian, A.; Belova, E.; Lee, Y.-S.

    2015-06-01

    A small, 54 MHz wind-profiler radar, MARA, was operated at Troll, Antarctica (72° S, 2.5° E), continuously from November 2011 to January 2014, covering two complete Antarctic winters. Despite very low power, MARA observed echoes from heights of 55-80 km (polar mesosphere winter echoes, PMWE) on 60% of all winter days (from March to October). This contrasts with previous reports from radars at high northern latitudes, where PWME have been reported only by very high power radars or during rare periods of unusually high electron density at PMWE heights, such as during solar proton events. Analysis shows that PWME at Troll were not related to solar proton events but were often closely related to the arrival of high-speed solar wind streams (HSS) at the Earth, with PWME appearing at heights as low as 56 km and persisting for up to 15 days following HSS arrival. This demonstrates that HSS effects penetrate directly to below 60 km height in the polar atmosphere. Using local observations of cosmic-noise absorption (CNA), a theoretical ionization/ion-chemistry model and a statistical model of precipitating energetic electrons associated with HSS, the electron density conditions during the HSS events are estimated. We find that PMWE detectability cannot be explained by these variations in electron density and molecular-ion chemistry alone. PWME become detectable at different thresholds depending on solar illumination and height. In darkness, PWME are detected only when the modelled electron density is above a threshold of about 1000 cm-3, and only above 75 km height, where negative ions are few. In daylight, the electron density threshold falls by at least 2 orders of magnitude and PWME are found primarily below 75 km height, even in conditions when a large proportion of negative ions is expected. There is also a strong dawn-dusk asymmetry with PWME detected very rarely during morning twilight but often during evening twilight. This behaviour cannot be explained if PMWE

  14. Remote Sensing of PMCs with the Polar Suborbital Science in the Upper Mesosphere (PoSSUM) Lidar

    NASA Astrophysics Data System (ADS)

    Mitchell, S.; Thayer, J. P.; Reimuller, J. D.

    2013-12-01

    The Polar Suborbital Science in the Upper Mesosphere (PoSSUM) experiment is a modular observatory readily integrated into commercial manned Reusable Suborbital Launch Vehicles (RSLV) for aeronomy, remote sensing, solar physics, astronomy/astrophysics, and Earth observations. The proposed observatory, scheduled for deployment in July 2015, is being designed to operate onboard the XCOR Lynx and Virgin Galactic SpaceShipTwo vehicles. The observatory will enable unprecedented capabilities to dedicate low-cost suborbital campaigns for the study of the small-scale dynamics of polar mesospheric clouds (PMC) by obtaining imagery and remotely sensed data from apogee altitudes in excess of 100 km. A key component of the observatory is the PoSSUM Lidar, a Rayleigh/Mie backscatter lidar currently being designed at the University of Colorado at Boulder. The proposed instrument transmitter consists of a 532 nm linearly polarized laser coupled with conditioning and steering optics. The receiver employs a photon counting approach to detect the received optical signals backscattered from PMCs during flight operations. The design of the PoSSUM Lidar will be presented, including the unique challenges associated with developing a lidar instrument for operations onboard a RSLV. Initial simulation data will be explored, including a discussion of the expected science products output by the lidar, such as PMC height and density, as well as the potential for depolarization measurements to evaluate PMC asphericity.

  15. Light in Condensed Matter in the Upper Atmosphere as the Origin of Homochirality: Circularly Polarized Light from Rydberg Matter

    NASA Astrophysics Data System (ADS)

    Holmlid, Leif

    2009-08-01

    Clouds of the condensed excited Rydberg matter (RM) exist in the atmospheres of comets and planetary bodies (most easily observed at Mercury and the Moon), where they surround the entire bodies. Vast such clouds are recently proposed to exist in the upper atmosphere of Earth (giving rise to the enormous features called noctilucent clouds, polar mesospheric clouds, and polar mesospheric summer radar echoes). It has been shown in experiments with RM that linearly polarized visible light scattered from an RM layer is transformed to circularly polarized light with a probability of approximately 50%. The circular Rydberg electrons in the magnetic field in the RM may be chiral scatterers. The magnetic and anisotropic RM medium acts as a circular polarizer probably by delaying one of the perpendicular components of the light wave. The delay process involved is called Rabi-flopping and gives delays of the order of femtoseconds. This strong effect thus gives intense circularly polarized visible and UV light within RM clouds. Amino acids and other chiral molecules will experience a strong interaction with this light field in the upper atmospheres of planets. The interaction will vary with the stereogenic conformation of the molecules and in all probability promote the survival of one enantiomer. Here, this strong effect is proposed to be the origin of homochirality. The formation of amino acids in the RM clouds is probably facilitated by the catalytic effect of RM.

  16. Light in condensed matter in the upper atmosphere as the origin of homochirality: circularly polarized light from Rydberg matter.

    PubMed

    Holmlid, Leif

    2009-01-01

    Clouds of the condensed excited Rydberg matter (RM) exist in the atmospheres of comets and planetary bodies (most easily observed at Mercury and the Moon), where they surround the entire bodies. Vast such clouds are recently proposed to exist in the upper atmosphere of Earth (giving rise to the enormous features called noctilucent clouds, polar mesospheric clouds, and polar mesospheric summer radar echoes). It has been shown in experiments with RM that linearly polarized visible light scattered from an RM layer is transformed to circularly polarized light with a probability of approximately 50%. The circular Rydberg electrons in the magnetic field in the RM may be chiral scatterers. The magnetic and anisotropic RM medium acts as a circular polarizer probably by delaying one of the perpendicular components of the light wave. The delay process involved is called Rabi-flopping and gives delays of the order of femtoseconds. This strong effect thus gives intense circularly polarized visible and UV light within RM clouds. Amino acids and other chiral molecules will experience a strong interaction with this light field in the upper atmospheres of planets. The interaction will vary with the stereogenic conformation of the molecules and in all probability promote the survival of one enantiomer. Here, this strong effect is proposed to be the origin of homochirality. The formation of amino acids in the RM clouds is probably facilitated by the catalytic effect of RM. PMID:19586392

  17. Mesopause Horizontal wind estimates based on AIM CIPS polar mesospheric cloud pattern matching

    NASA Astrophysics Data System (ADS)

    Rong, P.; Yue, J.; Russell, J. M.; Gong, J.; Wu, D. L.; Randall, C. E.

    2013-12-01

    A cloud pattern matching approach is used to estimate horizontal winds in the mesopause region using Polar Mesospheric Cloud (PMC) albedo data measured by the Cloud Imaging and Particle Size instrument on the AIM satellite. Measurements for all 15 orbits per day throughout July 2007 are used to achieve statistical significance. For each orbit, eighteen out of the twenty-seven scenes are used for the pattern matching operation. Some scenes at the lower latitudes are not included because there is barely any cloud coverage for these scenes. The frame-size chosen is about 12 degrees in longitude and 3 degrees in latitude. There is no strict criterion in choosing the frame size since PMCs are widespread in the polar region and most local patterns do not have a clearly defined boundary. The frame moves at a step of 1/6th of the frame size in both the longitudinal and latitudinal directions to achieve as many 'snap-shots' as possible. A 70% correlation is used as a criterion to define an acceptable match between two patterns at two time frames; in this case the time difference is about 3.6 minutes that spans every 5 'bowtie' scenes. A 70% criterion appears weak if the chosen pattern is expected to act like a tracer. It is known that PMC brightness varies rapidly with a changing temperature and water vapor environment or changing nucleation conditions, especially on smaller spatial scales; therefore PMC patterns are not ideal tracers. Nevertheless, within a short time span such as 3.6 minutes a 70% correlation is sufficient to identify two cloud patterns that come from the same source region, although the two patterns may exhibit a significant difference in the actual brightness. Analysis of a large number of matched cloud patterns indicates that over the 3.6-minute time span about 70% of the patterns remain in the same locations. Given the 25-km2 horizontal resolution of CIPS data, this suggests that the overall magnitude of horizontal wind at PMC altitudes (~80-87 km) in

  18. The variability of stratospheric and mesospheric NO2 in the polar winter night observed by LIMS. [Limb Infrared Monitor of Stratosphere

    NASA Technical Reports Server (NTRS)

    Russell, M. J., III; Remsberg, E. E.; Callis, L. B.; Solomon, S.; Gordley, L. L.

    1984-01-01

    The LIMS experiment sounded the upper atmosphere from late October 1978 to late May 1979 and provided vertical profiles of atmospheric temperature, 03, H2O, HNO3, and NO2. Radiance averaging was used before retrieval to measure the altitude distribution of NO2 over the altitude range from the lower stratosphere into the mesosphere. Observations in the polar winter night region northward of about 70 deg N reveal NO2 levels near 175 ppbv at about 70 km, and they show a significant longitudinal variability (factor of 4 to 7). A definite temporal trend exists, showing a buildup of mesospheric and stratospheric NO2 during the polar night and a subsequent slowing of the increase of decline after sunlight returns, depending on altitude. The data represent the first experimental evidence that the thermosphere is an NO(x) source for the mesosphere and stratosphere.

  19. Satellite observations of polar mesospheric clouds by the solar backscattered ultraviolet spectral radiometer - Evidence of a solar cycle dependence

    NASA Technical Reports Server (NTRS)

    Thomas, Gary E.; Mcpeters, Richard D.; Jensen, Eric J.

    1991-01-01

    Results are presented on eight years of satellite observations of the polar mesospheric clouds (PMCs) by the SBUV spectral radiometer, showing that PMCs occur in the summertime polar cap regions of both hemispheres and that they exhibit year-to-year variability. It was also found that the increase in the PMC occurrence frequency was inversely correlated with solar activity. Two kinds of hemispherical asymmetries could be identified: (1) PMCs in the Northern Hemisphere were significantly brighter than in the Southern Hemisphere, in accordance with previous results derived from SME data; and (2) the solar cycle response in the south is more pronounced than in the north. The paper also describes the cloud detection algorithm.

  20. Gravity Waves in Polar Mesosphere and Lower Thermosphere Revealed in a Whole-atmospheric Global Atmospheric Model

    NASA Astrophysics Data System (ADS)

    Song, I. S.; Jee, G.; Kim, B. M.

    2015-12-01

    Mesoscale gravity waves are simulated by carrying out the specified chemistry whole atmosphere community climate model (SC-WACCM) at the horizontal resolution of about 25 km to understand the origin of gravity waves in the polar mesosphere and lower thermosphere (MLT) and their propagation properties throughout the whole atmosphere. Modeled gravity waves are also compared with gravity-wave activities estimated from meteor radar observations made in Antarctica by Korea Polar Research Institute. For this comparison, SC-WACCM is initialized at a specific date and time using atmospheric state variables from the ground to the thermosphere obtained from various data sets such as operational analyses and empirical wind and temperature model results. Model initial conditions are corrected for mass and dynamical balance to reduce spurious waves due to initial shocks. At conference, preliminary results of the mesoscale SC-WACCM simulation and its comparison with observations will be presented.

  1. Rocket observations of positive ions during polar mesosphere winter echo conditions at Andenes in January 2005; first analysis and interpretations

    NASA Astrophysics Data System (ADS)

    Brattli, A.; Rapp, M.; Singer, W.; Lattek, R.; Friedrich, M.; Havnes, O.; Blix, T. A.; Svenes, K. R.

    2005-08-01

    On Janurary 18, 2005, two instrumented miniaturised rocket payloads, each with a Positive Ion Probe (PIP) and a Faraday rotation/differential absorption experiment, were launched from Andøya Rocket Range (69°N). The instrumented payloads were launched into conditions with Polar Mesosphere Winter Echoes (PMWE) as part of a salvo of meteorological rockets measuring temperature and wind using falling spheres and chaff. Layers of PMWE were detected in the altitude range 55-77 km by the 53.5 MHz ALWIN radar. Fluctuations in the ion density, as measured in situ by the instrumented payloads, show that there was turbulence inside the PMWE layers, but not above/below and between. Data from the PIPs are analysed and related to the geophysical conditions, as observed with the ALWIN radar and meteorological rockets.

  2. Preliminary Study on Active Modulation of Polar Mesosphere Summer Echoes with the Radio Propagation in Layered Space Dusty Plasma

    NASA Astrophysics Data System (ADS)

    Zhou, Shengguo; Li, Hailong; Fu, Luyao; Wang, Maoyan

    2016-06-01

    Radar echoes intensity of polar mesosphere summer echoes (PMSE) is greatly affected by the temperature of dusty plasma and the frequency of electromagnetic wave about the radar. In this paper, a new method is developed to explain the active experiment results of PMSE. The theory of wave propagation in a layered media is used to study the propagation characteristics of an electromagnetic wave at different electron temperatures. The simulation results show that the variation tendency of the reflected power fraction almost agrees with the results observed by radar in the European Incoherent Scatter Scientific Association (EISCAT). The radar echoes intensity of PMSE greatly decreases with the increase of the radio frequency and the enhancement of the electron temperature. supported by National Natural Science Foundation of China (Nos. 41104097 and 41304119) and by the National Key Laboratory of Electromagnetic Environment, China Research Institute of Radiowave Propagation (CRIRP)

  3. Laboratory studies of VUV photochemistry of water ice: measurements of photodesorption rates and implication for Polar Mesospheric Clouds

    NASA Astrophysics Data System (ADS)

    Kulikov, Mikhail; Feigin, Alexander; Ignatov, Stanislav; Sennikov, Petr; Schrems, Otto

    Polar Mesospheric Clouds (PMC) are the highest clouds of the Earth's atmosphere. They are formed during summer at middle to high latitudes in an altitude range between 80 and 90 km when the air temperature drops below 150K. The particles of PMC consist primarily of ice [1] and are formed as a result of water vapor condensation. In the day time, PMC are subjected to strong solar Lyman -α irradiation with the wavelength of 121.6 nm which penetrates into ice particles and is absorbed essentially. This leads to photodissociation of H2 O molecules and to formation of mobile and chemically active components in the solid phase. As a result, a whole spectrum of physicochemical processes can be initiated inside the particles: diffusion of primary products, chemical formation of secondary products, accumulation of both type of products in the ice matrix and their escaping into gas-phase. Murray and Plane [2] hypothesized that the last process is dominant, i.e. each Lyman -α photon absorbed by a particle of PMC results in the ejection of one H atom and one OH radical into gas phase that provides essential enhancement of HOx concentration with a corresponding increase in Ox removal. Nevertheless, they justly pointed to the need of laboratory measurements of the H and OH yield from ice under conditions pertinent to the summer mesosphere. We have carried out first laboratory studies of water ice photochemistry to acquiring knowledge about physicochemical processes inside particles of PMC initiated by solar irradiation. The experimental set-up used includes a high-vacuum chamber, a gas-inlet system, a refrigerator-cryostat with temperature controller, a FTIR spectrometer, a vacuum ultraviolet hydrogen lamp and a microwave generator. This work presents results of measurements of the absolute photodesorption rate (loss of substance due to the escape of photoproducts into gas phase) from thin (20-100nm) water ice samples at temperatures of 120-150 K. The data obtained demonstrate

  4. An Albedo-Ice Regression Method for Determining Ice Water Content of Polar Mesospheric Clouds from UV Observations

    NASA Astrophysics Data System (ADS)

    Thomas, G. E.; Bardeen, C.; Benze, S.

    2014-12-01

    Simulations of Polar Mesospheric Cloud (PMC) brightness and ice water content (IWC) are used to develop a simple robust method for IWC retrieval from UV satellite observations. We compare model simulations of IWC with retrievals from the UV Cloud Imaging and Particle Size (CIPS) experiment on board the satellite mission Aeronomy for Ice in the Mesosphere (AIM). This instrument remotely senses scattered brightness related to the vertically-integrated ice content. Simulations from the Whole Atmosphere Community Climate Model (WACCM), a chemistry climate model, is combined with a sectional microphysics model based on the Community Aerosol and Radiation Model for Atmospheres (CARMA). The model calculates high-resolution three-dimensional size distributions of ice particles. The internal variability is due to geographic and temporal variation of temperature and dynamics, water vapor, and meteoric dust. We examine all simulations from a single model day (we chose northern summer solstice) which contains several thousand model clouds. Accurate vertical integrations of the albedo and IWC are obtained. The ice size distributions are thus based on physical principles, rather than artificial analytic distributions that are often used in retrieval algorithms from observations. Treating the model clouds as noise-free data, we apply the CIPS algorithm to retrieve cloud particle size and IWC. The inherent "errors" in the retrievals are thus estimated. The linear dependence of IWC on albedo makes possible a method to derive IWC, called the Albedo-Ice regression method, or AIR. This method potentially unifies the variety of data from various UV experiments, with the advantages of (1) removing scattering-angle bias from cloud brightness measurements,(2) providing a physically-useful parameter (IWC),(3) deriving IWC even for faint clouds of small average particle sizes, and (4) estimating the statistical uncertainty as a random error, which bypasses the need to derive particle size.

  5. Noctilucent Clouds and regions with polar mesospheric summer echoes studied by means of rocket-borne electron and ion dc-probes

    NASA Astrophysics Data System (ADS)

    Blix, T. A.; Thrane, E. V.

    1993-10-01

    During the Noctilucent Cloud Campaign (NLC) from Esrange, Kiruna, Sweden in July-August 1991, detailed in situ mesurements were performed by means of plasma probes in the TURBO rocket payload. When launched through NLC and Polar Mesospheric Summer Echoes (PMSE) layers, these probes indicate that the NLC layer was associated with a one kilometer thick region containing heavy positive ions. Embedded in this layer were structures only a few tens of meters in vertical extent. These structures exhibited strongly enhanced ion current and corresponding sharp decreases of electron current. The observations indicate that the structures contain enhanced densities of light positive ions as well as heavy, negative charge carriers in the form of ions or particles. VHF radar measurements from the same site showed Polar Summer Mesospheric Echoes from a layer that at first was located just above the NLC layer, but the rocket results indicate that it later merged with the NLC-layer.

  6. Comparing nadir and limb observations of polar mesospheric clouds: The effect of the assumed particle size distribution

    NASA Astrophysics Data System (ADS)

    Bailey, Scott M.; Thomas, Gary E.; Hervig, Mark E.; Lumpe, Jerry D.; Randall, Cora E.; Carstens, Justin N.; Thurairajah, Brentha; Rusch, David W.; Russell, James M.; Gordley, Larry L.

    2015-05-01

    Nadir viewing observations of Polar Mesospheric Clouds (PMCs) from the Cloud Imaging and Particle Size (CIPS) instrument on the Aeronomy of Ice in the Mesosphere (AIM) spacecraft are compared to Common Volume (CV), limb-viewing observations by the Solar Occultation For Ice Experiment (SOFIE) also on AIM. CIPS makes multiple observations of PMC-scattered UV sunlight from a given location at a variety of geometries and uses the variation of the radiance with scattering angle to determine a cloud albedo, particle size distribution, and Ice Water Content (IWC). SOFIE uses IR solar occultation in 16 channels (0.3-5 μm) to obtain altitude profiles of ice properties including the particle size distribution and IWC in addition to temperature, water vapor abundance, and other environmental parameters. CIPS and SOFIE made CV observations from 2007 to 2009. In order to compare the CV observations from the two instruments, SOFIE observations are used to predict the mean PMC properties observed by CIPS. Initial agreement is poor with SOFIE predicting particle size distributions with systematically smaller mean radii and a factor of two more albedo and IWC than observed by CIPS. We show that significantly improved agreement is obtained if the PMC ice is assumed to contain 0.5% meteoric smoke by mass, in agreement with previous studies. We show that the comparison is further improved if an adjustment is made in the CIPS data processing regarding the removal of Rayleigh scattered sunlight below the clouds. This change has an effect on the CV PMC, but is negligible for most of the observed clouds outside the CV. Finally, we examine the role of the assumed shape of the ice particle size distribution. Both experiments nominally assume the shape is Gaussian with a width parameter roughly half of the mean radius. We analyze modeled ice particle distributions and show that, for the column integrated ice distribution, Log-normal and Exponential distributions better represent the range

  7. Medium polarization in asymmetric nuclear matter

    NASA Astrophysics Data System (ADS)

    Zhang, S. S.; Cao, L. G.; Lombardo, U.; Schuck, P.

    2016-04-01

    The influence of the medium polarization on the effective nuclear interaction of asymmetric nuclear matter is calculated in the framework of the induced interaction theory. The strong isospin dependence of the density and spin-density fluctuations is studied as it is driven by the interplay between the neutron and proton medium polarizations. Going from symmetric nuclear matter to pure neutron matter, the crossover of the induced interaction from attractive to repulsive in the spin-singlet state is determined as a function of the isospin imbalance. The density range in which the crossover occurs is also determined. For the spin-triplet state the induced interaction turns out to be always repulsive. The implications of the results for neutron star superfluid phases are briefly discussed.

  8. Studying the Inter-Hemispheric Coupling During Polar Summer Mesosphere Warming in 2002

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Feofilov, Artem; Pesnell, William; Kutepov, Alexander A.

    2010-01-01

    It has been found that the northern summer polar mesopause region in 2002 was warmer than normal and of shorter duration than for other years analyzed. Theoretical studies have implied that the abnormal characteristics of this polar summer were generated by unusual dynamical processes occurring in the southern polar winter hemisphere. We have used data from the SABER instrument aboard the NASA TIMED Satellite to study these processes for polar summer periods of 2002-2009. For background, SABER is a broadband limb scanning radiometer that measures a large number of minor atmospheric constituents as well as pressure and temperature in the 13-110 km altitude range over most of the globe.We will use SABER temperature data to illustrate the correlated heating seen between the southern and northern hemispheres during June and July 2002. We will then describe the approach to study the wave characteristics of the atmospheric temperature profiles and demonstrate the features that were unique for 2002 compared to the other years.

  9. The polar Sudden Stratospheric Warming (SSW) and it's possible manifestations in the equatorial Mesosphere-Thermosphere-Ionosphere

    NASA Astrophysics Data System (ADS)

    Pant, Tarun

    In this study, the variations in daytime mesopause temperature and the Equatorial Electrojet over equator during Sudden Stratospheric Warming (SSW) events over high latitudes have been investigated. To reflect upon the stratospheric conditions NCEP-NCAR reanalysis data have also been used. This study indicates a possible dynamical coupling between the two regions through the planetary wave activity. The amplified wave signatures of quasi-16 day period are seen in the equatorial mesopause temperature and zonal mean polar stratospheric temperature (at 10 hPa) during the course of SSW. The possibility that the planetary waves over the polar stratosphere, which play an important role in the generation of SSW, could also have contribu-tion from the tropics has been indicated through numerical simulations in the past [Dunkerton, 1981], but due to the paucity of global measurements it could not be established unequivocally. These simulations also indicated the presence of a zero-wind line whose real counterparts were not observed in the atmosphere. The NCEP-NCAR reanalysis of stratospheric wind and tem-peratures clearly shows that (i) a dynamical feature similar to the zero-wind line appears over the tropics 60 days prior to the major warming and progresses poleward and, (ii) enhanced PW activity is seen almost simultaneously. This study shows that the recent SSW events had tropical associations. Further, favored occurrences of Equatorial Counter Electrojets (CEJs) with a quasi 16-day periodicity over Trivandrum (8.5oN, 76.5oE, 0.5oN diplat.) in association with the polar Stratospheric Sudden Warming (SSW) events are presented. It is seen that, the stratospheric temperature at 30 km over Trivandrum showed a sudden cooling prior to the SSW and the first bunch of CEJs occurred around this time. Stratospheric zonal mean zonal wind at 30 km exhibited a distinctly different pattern during the SSW period. These circula-tion changes are proposed to be conducive for the upward

  10. The polar Sudden Stratospheric Warming (SSW) and it's possible manifestations in the equatorial Mesosphere-Thermosphere-Ionosphere

    NASA Astrophysics Data System (ADS)

    Pant, Tarun; Vineeth, C.; Sridharan, R.

    In this study, the variations in daytime mesopause temperature and the Equatorial Electrojet over equator during Sudden Stratospheric Warming (SSW) events over high latitudes have been investigated. To reflect upon the stratospheric conditions NCEP-NCAR reanalysis data have also been used. This study indicates a possible dynamical coupling between the two regions through the planetary wave activity. The amplified wave signatures of quasi-16 day period are seen in the equatorial mesopause temperature and zonal mean polar stratospheric temperature (at 10 hPa) during the course of SSW. The possibility that the planetary waves over the polar stratosphere, which play an important role in the generation of SSW, could also have contribution from the tropics has been indicated through numerical simulations in the past [Dunkerton, 1981], but due to the paucity of global measurements it could not be established unequivocally. These simulations also indicated the presence of a zero-wind line whose real counterparts were not observed in the atmosphere. The NCEP-NCAR reanalysis of stratospheric wind and temperatures clearly shows that (i) a dynamical feature similar to the zero-wind line appears over the tropics 60 days prior to the major warming and progresses poleward and, (ii) enhanced PW activity is seen almost simultaneously. This study shows that the recent SSW events had tropical associations. Further, favored occurrences of Equatorial Counter Electrojets (CEJs) with a quasi 16-day periodicity over Trivandrum (8.5oN, 76.5oE, 0.5oN diplat.) in association with the polar Stratospheric Sudden Warming (SSW) events are presented. It is seen that, the stratospheric temperature at 30 km over Trivandrum showed a sudden cooling prior to the SSW and the first bunch of CEJs occurred around this time. Stratospheric zonal mean zonal wind at 30 km exhibited a distinctly different pattern during the SSW period. These circulation changes are proposed to be conducive for the upward

  11. Small-scale structure of O2(+) and proton hydrates in a Noctilucent Cloud and polar mesospheric summer echo of August 9/10 1991 above Kiruna

    NASA Technical Reports Server (NTRS)

    Balsiger, F.; Kopp, E.; Friedrich, M.; Torkar, K. M.; Walchli, U.

    1993-01-01

    A novel mass spectrometer designed to measure simultaneously positive ion composition in the mesosphere, was successfully launched during the NLC-91 project. Instruments supporting the mass spectrometer were a probed to measure both electrons and positive ions as well as a wave propagation experiment. The location of the Noctilucent Clouds (NLC) was determined by a particle impact sensor to detect secondary electrons and ions from the impact of NLC particle. The density of proton hydrates and of the related total ions is depleted in the NLC region at 83 km. An improved detection limit of 5 x 10(exp 4)/cu m for positive ions and improved height resolution revealed for the first time large gradients in the O2(+), H(+)(H2O)2 and H(+)(H2O)6 densities within a small height range of the order of 50 m. Such gradients at the altitude of NLC and Polar Mesospheric Summer Echoes (PMSE) are associated with strong variability of mesospheric water vapor, temperature and neutral air density.

  12. Polar thermospheric Joule heating, and redistribution of recombination energy in the upper mesosphere

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Harris, I.; Dube, M.

    1990-01-01

    Kellogg (1961), suggested that transport of atomic oxygen from the summer into the winter hemisphere and subsequent release of energy by three body recombination, O+O+N2 yields O2+N2+E, may contribute significantly to the so-called mesopause temperature anomaly. Earlier model calculations have shown that Kellogg's mechanism produces about a 10-percent increase in the temperature from summer to winter at 90 km. This process, however, is partly compensated by differential heating from absorption of UV radiation associated with dissociation of O2. In the auroral region of the thermosphere, there is a steady energy dissipation by Joule heating causing a redistribution and depletion of atomic oxygen due to wind-induced diffusion. With the removal of O, latent chemical energy normally released by three body recombination is also removed, and the result is that the temperature decreases by almost 2 percent near 90 km. Through dynamic feedback, this process reduces the depletion of atomic oxygen by about 25 percent and the temperature perturbation in the exosphere from 10 to 7 percent at polar latitudes. Under the influence of the internal dynamo interaction, the prevailing zonal circulation in the upper thermosphere changes direction when the redistribution of recombination energy is considered.

  13. On the formation of sharp gradients in electron density resulting from an ice-plasma feedback instabilities in the polar summer mesosphere

    NASA Astrophysics Data System (ADS)

    Yee, J.; Bahcivan, H.

    2014-12-01

    Polar Mesospheric Summer Echoes (PMSEs) have commonly been attributed to scattering from (1) volume-filled electron density turbulence and (2) extremely sharp (meter-scale) gradients in electron density. In-situ sounding rockets have measured both extended regions of turbulence as well as electron density ledges. Unlike the turbulence theory, which has been extensively studied, a theory on the formation of sharp edges has yet to be explored. In this study, we reconsider the study of Gumbel et al. [2002] on the influences of ice particles on the ion chemistry and propose a theory of ice-plasma feedback instability in order to explain the origin of sharp electron density gradients. A one-dimensional particle-in-cell simulation of a multi-constituent weakly-ionized plasma has been developed to capture the physics of proton-hydrates (H+[H20]n), ice, and plasma interactions on a spatial grid of approximately 25 m. The simulation captures (1) the development of the proton-hydrate chain starting at n=4 via Thomson's model and Natanson's recombination scheme, (2) the formation of ice nucleation on large cluster proton-hydrates (n > 73), (3) the attachment of electrons (and ions) to ice particles, and resulting depletion of the plasma density, which significantly accelerates the proton-hydrate chain and ionic nucleation of new ice particles, (4) and the development of an ice-plasma feedback instability whereby the repeated process of developing new ice particles leads to capture of even more electrons and further depletion of existing regions of lower plasma density. Since this feedback instability process is faster than typical aerosol diffusion rates in this region, existing gradients steepen to produce electron density ledges. Although ionic nucleation is not feasible as the major mesospheric nucleation process, it can become efficient locally, near the coldest parts of the mesosphere because the proton-hydrate chain development is extremely sensitive to ambient

  14. Polar mesospheric summer echoes at 78°N, 16°E, 2008: First results of the refurbished sounding system (SOUSY) Svalbard radar

    NASA Astrophysics Data System (ADS)

    Hall, C. M.; RöTtger, J.; Kuyeng, K.; Tsutsumi, M.; Dyrland, M.; Chau, J. L.

    2009-06-01

    The second-generation sounding system (SOUSY) 53.5-MHz mesosphere-stratosphere-troposphere (MST) radar at 78°N, 16°E on Svalbard has recently completed its inaugural summer, 2008, of polar mesospheric summer echoes (PMSE) observations. Here PMSE observations have been assembled in order to identify dates of the earliest and latest occurrences and how the frequency of PMSE occurrence correlates with dynamics and temperature, which are available from the collocated Nippon/Norway Svalbard Meteor 31-MHz Radar (NSMR). We find strong correlations between preferred PMSE altitude and low temperature, and between equatorward flow and occurrence rate. Temperature drops cause increases in PMSE occurrence: for the height interval 82-92 km, a drop of around 7 K increases the occurrence, typically by 1-2% d-1 and similarly for a 1 m s-1 increase in equatorward wind. A temperature drop of 5 K at 90 km altitude results in a lowering of the underlying preferred PMSE altitude by 1 km. This study therefore qualifies, at least for 78°N, 16°E and 2008, the dependence of PMSE occurrence rates and preferred heights on 90 km temperature and dynamics.

  15. Mesospheric mysteries

    SciTech Connect

    Crutzen, P.

    1997-09-26

    Although the chemistry of the upper stratosphere and mesosphere is quite simple with chemical ozone loss reactions being dominated by HOx catalysis, numerous studies have failed to find the expected agreement between odd oxygen production and destruction. This article discusses a solution to this discrepancy and how it relates to the whole understanding of upper atmosphere chemistry and the possibility of an external source of H2O. 10 refs., 1 fig.

  16. Fault system polarity: A matter of chance?

    NASA Astrophysics Data System (ADS)

    Schöpfer, Martin; Childs, Conrad; Manzocchi, Tom; Walsh, John; Nicol, Andy; Grasemann, Bernhard

    2015-04-01

    Many normal fault systems and, on a smaller scale, fracture boudinage exhibit asymmetry so that one fault dip direction dominates. The fraction of throw (or heave) accommodated by faults with the same dip direction in relation to the total fault system throw (or heave) is a quantitative measure of fault system asymmetry and termed 'polarity'. It is a common belief that the formation of domino and shear band boudinage with a monoclinic symmetry requires a component of layer parallel shearing, whereas torn boudins reflect coaxial flow. Moreover, domains of parallel faults are frequently used to infer the presence of a common décollement. Here we show, using Distinct Element Method (DEM) models in which rock is represented by an assemblage of bonded circular particles, that asymmetric fault systems can emerge under symmetric boundary conditions. The pre-requisite for the development of domains of parallel faults is however that the medium surrounding the brittle layer has a very low strength. We demonstrate that, if the 'competence' contrast between the brittle layer and the surrounding material ('jacket', or 'matrix') is high, the fault dip directions and hence fault system polarity can be explained using a random process. The results imply that domains of parallel faults are, for the conditions and properties used in our models, in fact a matter of chance. Our models suggest that domino and shear band boudinage can be an unreliable shear-sense indicator. Moreover, the presence of a décollement should not be inferred on the basis of a domain of parallel faults only.

  17. Electrodynamics of the high-latitude mesosphere

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.

    1989-01-01

    The discovery of apparent large (V/m) electric fields within the mesosphere suggests that this region is more active electrically than originally suspected. High-latitude observations have been particularly productive in developing new concepts regarding mesospheric electrodynamics. Several high-latitude observations of large mesospheric fields have been made under both quiet and aurorally active conditions but always below heights where enhanced ionizing radiations could significantly penetrate. Two measurements from Andoya, Norway, have also produced an anticorrelation of horizontal electric field directions with neutral wind velocities, leading to the theoretical description of a newly defined mechanism for V/m electric field generation involving wind-induced separation of charged aerosols. Evidence for mesospheric aerosols and winds exists at all latitudes but is most evident at high latitudes during the appearance of noctilucent and/or polar mesospheric clouds.

  18. Proof-of-Concept Study for Ground-based Millimetre-wave Observations of Horizontal Winds in the Polar Stratosphere and Mesosphere

    NASA Astrophysics Data System (ADS)

    Ford, George; Newnham, David; Pumphrey, Hugh

    2015-04-01

    We demonstrate the feasibility of stratosphericmesospheric zonal and meridional wind observations using ground-based passive millimetrewave radiometry with lownoise receivers and high-resolution spectrometers. Detailed observations of winds in the Polar Regions are essential to understand chemical transport, atmospheric dynamics, waves and tides, and improve knowledge of polar and global climate systems. Measurements in the altitude range 2070 km would fill the 'radar gap' and address the current sparse wind observations for the upper stratosphere and mesosphere that limits our understanding of vertical wave propagation and its impact on planetaryscale circulation. The Atmospheric Radiative Transfer Simulator (ARTS) and Qpack retrieval code is used to retrieve vertical wind profiles from simulations of lineofsight Doppler-shifted atmospheric emission lines above Halley station (75° 37'S, 26° 14'W), Antarctica. The ozone lines centred at 231.28 GHz, 249.79 GHz, and 249.96 GHz and the 230.54 GHz carbon monoxide line are used. The effect of clearsky winter/summer conditions, zenith angle, system temperature (Tsys), and spectrometer frequency resolution on the altitude coverage, measurement uncertainty, and height and time resolution of the retrieved wind profiles is presented. For radiometric observations of Dopplershifted ozone emission lines arising from horizontal winds in the range 1040 m s-1, and with Tsys = 1400 K, we estimate that daily mean zonal and meridional wind profiles covering the altitude range 2575 km with typical measurement uncertainty of 5 m s-1 and vertical resolution of ~12 km could be achieved.

  19. PERSPECTIVE: Snow matters in the polar regions

    NASA Astrophysics Data System (ADS)

    Sodeau, John

    2010-03-01

    to 30 times greater than those found in ice-free areas. The main question to ask is: how might the bromine have become released to the atmosphere? Many ideas have, in fact, been put forward over the last few years as to how such polar ocean-troposphere exchanges can take place. Much of the interest was driven by the so-called 'sudden' ozone depletion episodes first detected in Arctic air during the 1990s alongside simultaneous bromine 'explosions' which were monitored by ground-based instrumentation and satellite (as the radical BrO) over sea-ice covered by snowpack (Hausmann and Platt 1994, Schonhardt et al 2008). The likely precursors suggested, to date, have been sea-salt, frost-flowers and anthropogenic contents rather than organo- bromine matter (Simpson et al 2007). Associated processing routes including the formation of HOBr, the need for acidity, the involvement of trihalide ions and the potential role of freezing processes and the quasi-liquid layer have all been discussed in this context (Abbatt 1994, Neshyba et al 2009, O'Driscoll et al 2006). Computational work has also led to suggestions that preferential surface dispersion of the more highly polarizable halides (iodide and bromide ions) may lead to their direct interfacial reaction with atmospheric ozone leading to BrO or IO formation (Jungwirth and Winter 2008). The involvement of snow micro-algae in the production of halo-compounds such as CHBr3 and CH2Br2 in Antarctica cannot, of course, be ignored following the measurement of these compounds by Sturges and co-workers over 15 years ago (Sturges et al 1993). And the measurement of high levels of nutrient discussed in the recent work by Antony et al (2010) in the ice-cap areas do provide a basis for understanding why micro- algae growth in snow might be promoted. However the question still comes back to: how are these halo-compounds processed to produce 'active' species like BrO radicals, HOBr, Br atoms, Br2 gas or interhalogens such as BrCl? The

  20. Three-year lidar observational studies of physics and chemistry in the polar mesosphere and lower thermosphere at McMurdo, Antarctica

    NASA Astrophysics Data System (ADS)

    Chu, Xinzhao; McDonald, Adrian; Fuller-Rowell, Tim; Vadas, Sharon; Chen, Cao; Gardner, Chester S.; Yu, Zhibin; Lu, Xian; Zhao, GRA. Jian; Fong, Weichun; Huang, Wentao

    The polar mesosphere and thermosphere provide a unique natural laboratory for studying the complex physical, chemical, neutral dynamical and electrodynamics processes in the Earth’s atmosphere and space environment. However, this region remains one of the least understood regions of the atmosphere. In particular, very little is known about the neutral atmosphere in the altitude range of 100-200 km because observations of the neutral thermosphere were woefully incomplete and in critical need to advance our understanding of and ability to predict the Space-Atmosphere Interaction Region. The first lidar discovery of neutral iron (Fe) layers with gravity wave signatures in the thermosphere up to 155 km made by Chu lidar group in 2011 at McMurdo (77.8S, 166.7E), Antarctica was a breakthrough in the upper atmosphere research. Not only was this the first time for a single instrument to trace gravity waves from 30 to 155 km, but also it enabled the first direct measurements of neutral temperatures deep into the E-region, revealing the neutral-ion coupling and aurora-enhanced Joule heating. These new observations have opened the door to exploring the polar neutral thermosphere with ground-based instruments. Such a discovery is only a small portion of the rich datasets collected from McMurdo. Since December 2010 we have deployed an Fe Boltzmann lidar to McMurdo (77.8S, 166.7E), Antarctica via collaboration between the United States Antarctic Program (USAP) and Antarctica New Zealand (AntNZ). Nearly 4000 hours of data have been collected in the last three years covering all 12 months of a year, and the campaign is being continued for another five years to acquiring long-term datasets for polar research. Many new science discoveries have emerged from the data. In this paper we will focus on two record-setting events: One is the lidar detection of neutral Fe layers reaching over 170 km in the thermosphere, and another is the lidar marathon run of 174-hour continuous

  1. Thermal and dynamical perturbations in the winter polar mesosphere-lower thermosphere region associated with sudden stratospheric warmings under conditions of low solar activity

    NASA Astrophysics Data System (ADS)

    Lukianova, Renata; Kozlovsky, Alexander; Shalimov, Sergey; Ulich, Thomas; Lester, Mark

    2015-06-01

    The upper mesospheric neutral winds and temperatures have been derived from continuous meteor radar (MR) measurements over Sodankyla, Finland, in 2008-2014. Under conditions of low solar activity pronounced sudden mesospheric coolings linked to the major stratospheric warming (SSW) in 2009 and a medium SSW in 2010 are observed while there is no observed thermal signature of the major SSW in 2013 occurred during the solar maximum. Mesosphere-ionosphere anomalies observed simultaneously by the MR, the Aura satellite, and the rapid-run ionosonde during a period of major SSW include the following features. The mesospheric temperature minimum occurs 1 day ahead of the stratospheric maximum, and the mesospheric cooling is almost of the same value as the stratospheric warming (~50 K), the former decay faster than the latter. In the course of SSW, a strong mesospheric wind shear of ~70 m/s/km occurs. The wind turns clockwise (anticlockwise) from north-eastward (south-eastward) to south-westward (north-westward) above (below) 90 km. As the mesospheric temperature reaches its minimum, the gravity waves (GW) in the ionosphere with periods of 10-60 min decay abruptly while the GWs with longer periods are not affected. The effect is explained by selective filtering and/or increased turbulence near the mesopause.

  2. Spin polarized asymmetric nuclear matter and neutron star matter within the lowest order constrained variational method

    SciTech Connect

    Bordbar, G. H.; Bigdeli, M.

    2008-01-15

    In this paper, we calculate properties of the spin polarized asymmetrical nuclear matter and neutron star matter, using the lowest order constrained variational (LOCV) method with the AV{sub 18}, Reid93, UV{sub 14}, and AV{sub 14} potentials. According to our results, the spontaneous phase transition to a ferromagnetic state in the asymmetrical nuclear matter as well as neutron star matter do not occur.

  3. Charge Distribution in Mesospheric Clouds

    SciTech Connect

    Misra, Shikha; Mishra, S. K.; Sodha, M. S.

    2011-11-29

    This work presents an analytical model for the physical understanding of the charge distribution on pure (with high work function) and dirty (with low work function) ice dust particles in polar mesospheric clouds PMCs (NLCs and PMSEs). The analysis is based on number and energy balance of constituents and allows the charge to be only an integral multiple (positive or negative) of the electronic charge.

  4. Simulataneous observations of polar mesosphere winter echo and cosmic noise absorption based on the PANSY radar in the Antarctic (69.0°S, 39.6°E)

    NASA Astrophysics Data System (ADS)

    Nishiyama, Takanori; Nakamura, Takuji; Tsutsumi, Masaki; Tanaka, Yoshi; Sato, Toru; Nishimura, Koji; Sato, Kaoru; Tomikawa, Yoshihiro; Kohma, Masashi

    2016-07-01

    In the Mesosphere and lower Thermosphere, both neutral turbulence and ionization of atmosphere due to solar radiations cause irregularities of refractive index, and as a result back scatter echoes from that altitude are frequently observed by radars on the ground. In the mesosphere, Polar Mesosphere Winter Echo (PMWE) is known as back scatter echo from 55 to 85 km in the mesosphere, and it has been observed by MST and IS radar in polar region during non-summer period. PMWE occurrence rate is known to be quite low (2.9%) [Zeller et al., 2006], partly because density of free electrons as scatterer is low in the dark mesosphere during winter. Thus, it is suggested that PMWE requires strong ionization of neutral atmosphere associated with Energetic Particles Precipitations (EPPs) during Solar Proton Events [Kirkwood et al., 2002] or during geomagnetically disturbed periods [Nishiyama et al., 2015]. However, direct comparison between occurrence of PMWE and background electron density by in-situ measurements has been limited yet [e.g., Luebken et al., 2006]. Neutral turbulence associated with breaking of atmospheric gravity waves is also important and its contribution to PMWE generation should be evaluated. The PANSY (Program of the Antarctic Syowa MST/IS) radar, which is the largest MST radar in Antarctica, observed many PMWE events since it has started mesosphere observations in June 2012. In addition, we established an application method of the PANSY radar as riometer, which makes it possible to estimate Cosmic Noise Absorptions (CNA) as proxy of relative variations on background electron density. In addition, electron density profiles from 60 to 150 km altitude are calculated by Ionospheric Model for the Auroral Zone (IMAZ) [McKinnell and Friedrich, 2007] and CNA estimated by the PANSY radar. In this presentation, we would like to focus on simultaneous PMWE and CNA observation on May 23, 2013 when large SPE took place in order to evaluate contributions of relative

  5. Nonthermal dark matter and the top polarization at collider

    NASA Astrophysics Data System (ADS)

    Gao, Yu

    2016-06-01

    We discuss the characteristic collider signatures, in particular a highly polarized resonant single-top channel for a minimal color triplet extension to the Standard Model. This extension provides baryogensis and a non-thermal production history of a dark matter candidate. We further discuss the implementation of both completely left and right-handed chiral interaction in the model and the difference in phenomenology between the two scenarios. If the color triplets are isospin singlets, the dark matter candidate mass is 1 GeV and the single-top quarks are strictly right-handed polarized. Alternatively, the isospin-doublet color triplets lead to strictly left-handed single top events and a more extended particle spectrum.

  6. Effect of polarization on superfluidity in low density neutron matter

    NASA Technical Reports Server (NTRS)

    Clark, J. W.; Kallman, C.-G.; Yang, C.-H.; Chakkalakal, D. A.

    1976-01-01

    The singlet-state quasi-particle interaction in neutron matter is examined on the basis of results of a detailed evaluation of the Landau Fermi-liquid parameters for pure neutron effects, including polarization effects. This means that the interaction induced by exchange of density and spin-density excitations is taken into account. It is shown that polarization actually works to suppress the pairing matrix elements, owing to the spin dependence of the quasi-particle interaction and, ultimately, the balance of attraction, repulsion, and spin dependence in the fundamental two-neutron interaction. Since the isotropic energy gap and the condensation energy in low-density neutron-star matter are extremely sensitive functions of the pairing matrix elements, they will also be suppressed by the polarizability of the neutron medium.

  7. On the spectral induced polarization signature of soil organic matter

    NASA Astrophysics Data System (ADS)

    Schwartz, N.; Furman, A.

    2014-01-01

    Although often composing a non-negligible fraction of soil cation exchange capacity (CEC), the impact of soil organic matter (OM) on the electrical properties of soil has not been thoroughly investigated. In this research the impact of soil OM on the spectral induced polarization (SIP) signature of soil was investigated. Electrical and chemical measurements for two experiments using the same soil, one with calcium as the dominant cation and the other with sodium, with different concentration of OM were performed. Our results show that despite the high CEC of OM, a decrease in polarization and an increase in relaxation time with increasing concentration of OM is observed. For the soil with calcium as the dominant cation, the decreases in polarization and the increase in relaxation time were stronger. We explain these non-trivial results by accounting for the interactions between the OM and the soil minerals. We suggest that the formation of organo-mineral complexes reduce ionic mobility, explaining both the decrease in polarization and the increase in relaxation time. These results demonstrate the important role of OM on SIP response of soil, and call for a further research in order to establish a new polarization model that will include the impact of OM on soil polarization.

  8. Spectral Induced Polarization Signature of Soil Organic Matter

    NASA Astrophysics Data System (ADS)

    Schwartz, Nimrod; Furman, Alex

    2015-04-01

    Although often composing a non-negligible fraction of soil cation exchange capacity (CEC), the impact of soil organic matter (OM) on the electrical properties of soil has not been thoroughly investigated. In this research the impact of soil OM on the spectral induced polarization (SIP) signature of soil was investigated. Electrical and chemical measurements for two experiments using the same soil, one with calcium as the dominant cation and the other with sodium, with different concentration of OM were performed. Our results show that despite the high CEC of OM, a decrease in polarization and an increase in relaxation time with increasing concentration of OM is observed. For the soil with calcium as the dominant cation, the decreases in polarization and the increase in relaxation time were stronger. We explain these non-trivial results by accounting for the interactions between the OM and the soil minerals. We suggest that the formation of organo-mineral complexes reduce ionic mobility, explaining both the decrease in polarization and the increase in relaxation time. These results demonstrate the important role of OM on SIP response of soil, and call for a further research in order to establish a new polarization model that will include the impact of OM on soil polarization.

  9. A study of the origin, nature, and behavior of particulate matter and metallic atoms in the mesosphere, lower thermosphere, and at the mesopause. [using lidar data

    NASA Technical Reports Server (NTRS)

    Poultney, S. K.

    1973-01-01

    In a study of particulate matter and metallic atoms in the vicinity of the mesopause, three areas have received the most effort. These areas are: the significance of cometary dust influxes to the earth's atmosphere; the relation of nightglows to atmospheric motions and aerosols; and the feasibility of using an airborne resonant scatter lidar to study polar noctilucent clouds, the sodium layer, and fireball dust.

  10. Bores In The Mesosphere

    NASA Astrophysics Data System (ADS)

    Smith, S. M.

    Bores are a special type of propagating hydraulic jump. They are a relatively common wave phenomenon in the Earth's oceans, rivers and lower atmosphere but they have been observed only rarely in the mesosphere. We will review the mesospheric bore phenomenon and present wide-field imaging observations of one particularly bright bore event seen at two widely-spaced (500 km) locations in the south-western United States: McDonald Observatory (MDO), Texas and the Starfire Optical Range (SOR), New Mexico. The measurements were supplemented with radar wind measurements, also made at the SOR, and by Na resonance lidar temperature measurements made at Fort Collins, Colorado, approximately 1100 km to the north of MDO. The multi- diagnostic observations provided evidence that mesospheric bores are associated with ducting regions in the mesosphere which allow them to travel distances of over 1500 km and exhibit lifetimes of over 6 hours.

  11. Aeronomy of Ice in the Mesosphere (AIM)

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The overall goal of the Aeronomy of Ice in the Mesosphere (AIM) experiment is to resolve why Polar Mesospheric Clouds form and why they vary. By measuring PMCs and the thermal, chemical and dynamical environment in which they form, we will quanti@ the connection between these clouds and the meteorology of the polar mesosphere. In the end, this will provide the basis for study of long-term variability in the mesospheric climate and its relationship to global change. The results of AIM will be a rigorous validation of predictive models that can reliably use past PMC changes and present trends as indicators of global change. The AIM goal will be achieved by measuring PMC extinction, brightness, spatial distribution, particle size distributions, gravity wave activity, dust influx to the atmosphere and precise, vertical profile measurements of temperature, H20, C&, 0 3 , C02, NO. and aerosols. These data can only be obtained by a complement of instruments on an orbiting spacecraft (S/C).

  12. Discharges in the Stratosphere and Mesosphere

    NASA Astrophysics Data System (ADS)

    Siingh, Devendraa; Singh, R. P.; Singh, Ashok K.; Kumar, Sanjay; Kulkarni, M. N.; Singh, Abhay K.

    2012-09-01

    In the present paper salient features of discharges in the stratosphere and mesosphere (namely sprites, halos, blue starters, blue jets, gigantic jets and elves), are discussed. The electrostatic field due to charge imbalance during lightning processes may lead to stratospheric/mesospheric discharges either through the conventional breakdown based on streamers and leaders or relativistic runaway mechanism. Most (not all) of the observed features of sprites, halos and jets are explained by this processes. Development and evolution of streamers are based on the local transient electrostatic field and available ambient electron density which dictate better probability in favor of positive cloud-to-ground discharges, and thus explains the polarity asymmetry in triggering sprites and streamers. Elves are generated by electromagnetic pulse radiated by return stroke currents of cloud-to-ground/inter-cloud discharges. Generation of the both donut and pancake shape elves are explained. Electrodynamic features of thunderstorms associated with stratospheric/mesospheric discharges are summarized including current and charge moment associated with relevant cloud-to-ground discharges. The hypothesis relating tropospheric generated gravity waves and mesospheric discharges are also discussed. Finally some interesting problems are listed.

  13. Scientific objectives of the Solar Mesosphere Explorer mission

    NASA Technical Reports Server (NTRS)

    Thomas, G. E.; Barth, C. A.; Hansen, E. R.; Hord, C. W.; Lawrence, G. M.; Mount, G. H.; Rottman, G. J.; Rusch, D. W.; Stewart, A. I.; Thomas, R. J.

    1980-01-01

    The paper describes the NASA Solar Mesosphere Explorer mission which will study mesospheric ozone and the processes which form and destroy it, measure the ozone density and its altitude distribution from 30 to 80 km, monitor incoming solar UV radiation, and provide a rigorous test of the photochemical equilibrium theory of the mesospheric oxygen-hydrogen system. Five instruments will be carried on the polar-orbiting spacecraft: UV ozone, IR airglow, and visible NO2 programmable Ebert-Fastie spectrometers, a four-channel IR radiometer, and a solar UV spectrometer. Atmospheric measurements will be made of the mesospheric and stratospheric ozone density distribution, water vapor density distribution, temperature profile, ozone photolysis rate, and NO2 density distribution. In addition, the solar UV monitor will measure both the 0.2-0.31 micron spectral region and the Lyman-alpha (0.1216 micron) contribution to the solar irradiance.

  14. Towards a quantitative kinetic theory of polar active matter

    NASA Astrophysics Data System (ADS)

    Ihle, T.

    2014-06-01

    A recent kinetic approach for Vicsek-like models of active particles is reviewed. The theory is based on an exact Chapman- Kolmogorov equation in phase space. It can handle discrete time dynamics and "exotic" multi-particle interactions. A nonlocal mean-field theory for the one-particle distribution function is obtained by assuming molecular chaos. The Boltzmann approach of Bertin, et al., Phys. Rev. E 74, 022101 (2006) and J. Phys. A 42, 445001 (2009), is critically assessed and compared to the current approach. In Boltzmann theory, a collision starts when two particles enter each others action spheres and is finished when their distance exceeds the interaction radius. The average duration of such a collision, τ0, is measured for the Vicsek model with continuous time-evolution. If the noise is chosen to be close to the flocking threshold, the average time between collisions is found to be roughly equal to τ0 at low densities. Thus, the continuous-time Vicsek-model near the flocking threshold cannot be accurately described by a Boltzmann equation, even at very small density because collisions take so long that typically other particles join in, rendering Boltzmann's binary collision assumption invalid. Hydrodynamic equations for the phase space approach are derived by means of a Chapman-Enskog expansion. The equations are compared to the Toner-Tu theory of polar active matter. New terms, absent in the Toner-Tu theory, are highlighted. Convergence problems of Chapman-Enskog and similar gradient expansions are discussed.

  15. The Mega Mesospheric Parachute

    NASA Technical Reports Server (NTRS)

    Kloesel, Kurt J.; Oberto, Robert; Kinsey, Robert

    2005-01-01

    The current understanding and modeling of the upper reaches of the atmosphere is incomplete. Upper atmospheric interactions with the lower atmosphere, effects of ionizing radiation, high altitude cloud phenomena, and the dynamical interaction with the magnetosphere require greater definition. The scientific objective of obtaining a greater understanding of the upper atmosphere can be achieved by designing, implementing, testing, and utilizing a facility that provides long period in-situ measurements of the mesosphere. Current direct sub-sonic measurements of the upper atmosphere are hampered by the approximately one minute sub-sonic observation window of a ballistic sounding rocket regardless of the launch angle. In-situ measurements at greater than transonic speeds impart energy into the molecular atmospheric system and distort the true atmospheric chemistry. A long duration, sub-sonic capability will significantly enhance our ability to observe and measure: (1) mesospheric lightning phenomena (sprites and blue jets) (2) composition, structure and stratification of noctilucent clouds (3) physics of seasonal radar echoes, gravity wave phenomena (4) chemistry of mesospheric gaseous ratio mixing (5) mesospheric interaction of ionizing radiation (6) dynamic electric and magnetic fields This new facility will also provide local field measurements which complement those that can be obtained through external measurements from satellite and ground-based platforms. The 400 foot (approximately 130 meter) diameter lightweight mega-mesospheric parachute system, deployed with a sounding rocket, is proposed herein as a method to increase sub-sonic mesospheric measurement time periods by more than an order of magnitude. The report outlines a multi-year evolving science instrumentation suite in parallel with the development of the mega meso-chute facility. The developmental issues surrounding the meso-chute are chiefly materials selection (thermal and structural) and deployment

  16. Temperature Deviations in the Midlatitude Mesosphere During Stratospheric Warmings as Measured with Rayleigh-Scatter Lidar

    NASA Astrophysics Data System (ADS)

    Sox, Leda; Wickwar, Vincent; Fish, Chad; Herron, Joshua P.

    2016-06-01

    While mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are sparse. The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU) collected an extensive set of temperature data for 11 years in the 45-90 km altitude range. This work focuses on the extensive Rayleigh lidar observations made during six major SSW events that occurred between 1993 and 2004, providing a climatological study of the midlatitude mesospheric temperatures during these SSW events. An overall disturbance pattern was observed in the mesospheric temperatures during these SSWs. It included coolings in the upper mesosphere, comparable to those seen in the polar regions during SSW events, and warmings in the lower mesosphere.

  17. Jicamarca mesospheric observations

    NASA Technical Reports Server (NTRS)

    Royrvik, O.

    1983-01-01

    In explaining the scattering of VHF radar signals from the mesosphere there are two observational facts that must be accounted for. These are; (1) the aspect sensitivity of the scattered signal and that this aspect sensitivity is largest in the lower part of the mesosphere, and (2) the correlating between the scattered power and the signal correlation time. This behavior is similar to that of the scattering from the troposphere/stratosphere region, and it is suggested that the scattering mechanisms are similar in these three regions. Several different experiments are performed. They all show strong indications of aspect sensitivity and changing correlation between scattered power and correlation time. There is no indication of stratified reflecting layers unless these layers are modulated in space and time to a degree that they cannot be distinguished from turbulence in any other way than that they cause somewhat aspect sensitive scattering.

  18. Mesospheric cloud formations

    NASA Technical Reports Server (NTRS)

    Forbes, J. M.

    1980-01-01

    Formation of mesospheric clouds as a result of deposition of large amounts of H2O by the heavy lift launch vehicle (HLLV) of the solar power satellite system is discussed. The conditions which must be met in order to form and maintain clouds near the mesopause are described. The frequency and magnitude of H2O injections from the HLLV rocket exhaust are considered.

  19. Lowest order constrained variational calculation of polarized neutron matter at finite temperature

    SciTech Connect

    Bordbar, G. H.; Bigdeli, M.

    2008-11-15

    Some properties of polarized neutron matter at finite temperature have been studied using the lowest order constrained variational (LOCV) method with the Argonne V18 (AV18) potential. Our results indicate that a spontaneous transition to the ferromagnetic phase does not occur. Effective mass, free energy, magnetic susceptibility, entropy, and the equation of state of polarized neutron matter at finite temperature are also calculated. A comparison is also made between our results and those of other many-body techniques.

  20. Magnetometry with mesospheric sodium

    PubMed Central

    Higbie, James M.; Rochester, Simon M.; Patton, Brian; Holzlöhner, Ronald; Bonaccini Calia, Domenico; Budker, Dmitry

    2011-01-01

    Measurement of magnetic fields on the few 100-km length scale is significant for many geophysical applications including mapping of crustal magnetism and ocean circulation measurements, yet available techniques for such measurements are very expensive or of limited accuracy. We propose a method for remote detection of magnetic fields using the naturally occurring atomic sodium-rich layer in the mesosphere and existing high-power lasers developed for laser guide star applications. The proposed method offers a dramatic reduction in cost and opens the way to large-scale, parallel magnetic mapping and monitoring for atmospheric science, navigation, and geophysics. PMID:21321235

  1. Solar Mesosphere Explorer

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Five experiments and the instruments packages designed for use in studying reactions between sunlight, ozone, and other chemicals in the atmosphere as well as for determining how ozone concentrations are transported in the mesosphere are described. The spin-stabilized satellite carrying the experiments consists of an observatory module and a spacecraft bus. Powered by a solar array which charges the nickel-cadmium batteries, the satellite is to be inserted into a sun synchronous orbit by a two stage Delta 2310 launch vehicle. The mission objectives, spacecraft configurations, and various subsystems are described as well as the ground support and prelaunch operations.

  2. Magnetometry with mesospheric sodium.

    PubMed

    Higbie, James M; Rochester, Simon M; Patton, Brian; Holzlöhner, Ronald; Bonaccini Calia, Domenico; Budker, Dmitry

    2011-03-01

    Measurement of magnetic fields on the few 100-km length scale is significant for many geophysical applications including mapping of crustal magnetism and ocean circulation measurements, yet available techniques for such measurements are very expensive or of limited accuracy. We propose a method for remote detection of magnetic fields using the naturally occurring atomic sodium-rich layer in the mesosphere and existing high-power lasers developed for laser guide star applications. The proposed method offers a dramatic reduction in cost and opens the way to large-scale, parallel magnetic mapping and monitoring for atmospheric science, navigation, and geophysics. PMID:21321235

  3. Optical Pumping of Mesospheric Sodium: a New Measurement Capability

    NASA Technical Reports Server (NTRS)

    Heinrichs, R. M.; Jeys, T. H.; Wall, K. F.; Korn, J.; Hotaling, T. C.

    1992-01-01

    The first observation of laser-induced optical pumping in a remote sensing application is reported. We have observed a large variation in the amount of laser light resonantly backscattered from the earth's mesospheric sodium layer depending on the laser polarization. This is consistent with optical pumping of the mesospheric sodium atoms. A new lidar capability is being developed based on measurements of the rethermalization rate of the optically pumped sodium atoms. These measurements have potential applications in the fields of global warming research, spacecraft re-entry, and upper atmospheric dynamics.

  4. Coherent control of light-matter interactions in polarization standing waves.

    PubMed

    Fang, Xu; MacDonald, Kevin F; Plum, Eric; Zheludev, Nikolay I

    2016-01-01

    We experimentally demonstrate that standing waves formed by two coherent counter-propagating light waves can take a variety of forms, offering new approaches to the interrogation and control of polarization-sensitive light-matter interactions in ultrathin (subwavelength thickness) media. In contrast to familiar energy standing waves, polarization standing waves have constant electric and magnetic energy densities and a periodically varying polarization state along the wave axis. counterintuitively, anisotropic ultrathin (meta)materials can be made sensitive or insensitive to such polarization variations by adjusting their azimuthal angle. PMID:27514307

  5. Coherent control of light-matter interactions in polarization standing waves

    PubMed Central

    Fang, Xu; MacDonald, Kevin F.; Plum, Eric; Zheludev, Nikolay I.

    2016-01-01

    We experimentally demonstrate that standing waves formed by two coherent counter-propagating light waves can take a variety of forms, offering new approaches to the interrogation and control of polarization-sensitive light-matter interactions in ultrathin (subwavelength thickness) media. In contrast to familiar energy standing waves, polarization standing waves have constant electric and magnetic energy densities and a periodically varying polarization state along the wave axis. counterintuitively, anisotropic ultrathin (meta)materials can be made sensitive or insensitive to such polarization variations by adjusting their azimuthal angle. PMID:27514307

  6. Observations of neutral mesospheric smoke particles using triboelectric current measurements from a multi-surface Langmuir probe

    NASA Astrophysics Data System (ADS)

    Barjatya, A.; Friedrich, M.; Strelnikov, B.

    2014-12-01

    We present results from two recent mesospheric rocket flights which were part of the German WADIS campaign from Andoya Rocket Range. One rocket was flown in polar summer, and the other in early winter. The payloads carried a novel multi-surface Langmuir probe. Three fixed bias Langmuir probes with different surfaces: Stainless Steel, Nickel and Platinum were exposed to the mesospheric plasma environment. In addition to collecting thermal electrons, each surface is expected to interact differently with the neutral constituents of the mesosphere: neutral metal atoms, mesospheric smoke particles, ice particles, etc. We estimate these particle densities from the measured electric current data.

  7. Finite-temperature calculations for spin-polarized asymmetric nuclear matter with the lowest order constrained variational method

    SciTech Connect

    Bigdeli, M.; Bordbar, G. H.; Poostforush, A.

    2010-09-15

    The lowest order constrained variational technique has been used to investigate some of the thermodynamic properties of spin-polarized hot asymmetric nuclear matter, such as the free energy, symmetry energy, susceptibility, and equation of state. We have shown that the symmetry energy of the nuclear matter is substantially sensitive to the value of spin polarization. Our calculations show that the equation of state of the polarized hot asymmetric nuclear matter is stiffer for higher values of the polarization as well as the isospin asymmetry parameter. Our results for the free energy and susceptibility show that spontaneous ferromagnetic phase transition cannot occur for hot asymmetric matter.

  8. Characterization and origin of polar dissolved organic matter from the Great Salt Lake

    USGS Publications Warehouse

    Leenheer, J.A.; Noyes, T.I.; Rostad, C.E.; Davisson, M.L.

    2004-01-01

    Polar dissolved organic matter (DOM) was isolated from a surface-water sample from the Great Salt Lake by separating it from colloidal organic matter by membrane dialysis, from less-polar DOM fractions by resin sorbents, and from inorganic salts by a combination of sodium cation exchange followed by precipitation of sodium salts by acetic acid during evaporative concentration. Polar DOM was the most abundant DOM fraction, accounting for 56% of the isolated DOM. Colloidal organic matter was 14C-age dated to be about 100% modern carbon and all of the DOM fractions were 14C-age dated to be between 94 and 95% modern carbon. Average structural models of each DOM fraction were derived that incorporated quantitative elemental and infrared, 13C-NMR, and electrospray/mass spectrometric data. The polar DOM model consisted of open-chain N-acetyl hydroxy carboxylic acids likely derived from N-acetyl heteropolysaccharides that constituted the colloidal organic matter. The less polar DOM fraction models consisted of aliphatic alicyclic ring structures substituted with carboxyl, hydroxyl, ether, ester, and methyl groups. These ring structures had characteristics similar to terpenoid precursors. All DOM fractions in the Great Salt Lake are derived from algae and bacteria that dominate DOM inputs in this lake.

  9. Gravitomagnetic acceleration of accretion disk matter to polar jets

    NASA Astrophysics Data System (ADS)

    Poirier, John; Mathews, Grant

    2016-03-01

    The motion of the masses of an accretion disk around a black hole creates a general relativistic, gravitomagnetic field (GEM) from the moving matter (be it charged or uncharged) of the accretion disk. This GEM field accelerates moving masses (neutral or charged) near the accretion disk vertically upward and away from the disk, and then inward toward the axis of the disk. As the accelerated material nears the axis with approximately vertical angles, a frame dragging effect contributes to the formation of narrow jets emanating from the poles. This GEM effect is numerically evaluated in the first post Newtonian (1PN) approximation from observable quantities like the mass and velocity of the disk. This GEM force is linear in the total mass of the accretion disk matter and quadratic in the velocity of matter near to the disk with approximately the same velocity. Since these masses and velocities can be quite high in astrophysical contexts, the GEM force, which in other contexts is weak, is quite significant. This GEM effect is compared to the ordinary electromagnetic effects applied to this problem in the past.

  10. Impact of molecular diffusion on the CO2 distribution and the temperature in the mesosphere

    NASA Astrophysics Data System (ADS)

    Chabrillat, Simon; Kockarts, Gaston; Fonteyn, Dominique; Brasseur, Guy

    2002-08-01

    Modelling the energy budget in the mesosphere and lower thermosphere requires a precise evaluation of CO2 distribution in this region. This distribution is primarily determined by competition between vertical eddy diffusion and molecular diffusion. A simple algorithm is proposed to take into account both processes, at all altitudes. Using the SOCRATES bi-dimensional model of the middle atmosphere, we show that molecular diffusion has a direct impact on CO2 vertical distribution down to approximately 80 km altitude, i.e. well into the mesosphere and below the turbopause altitude. A sensitivity study with regard to different aeronomical processes shows that molecular diffusion has the deepest influence in the mesospheric polar night region. Our model shows that molecular diffusion of CO2 is responsible for a polar night mesopause 12 K warmer than if this process was neglected. Hence, dynamical models should take this process in account across the whole mesospheric altitude range.

  11. Is dark matter an illusion created by the gravitational polarization of the quantum vacuum?

    NASA Astrophysics Data System (ADS)

    Hajdukovic, Dragan Slavkov

    2011-08-01

    Assuming that a particle and its antiparticle have the gravitational charge of the opposite sign, the physical vacuum may be considered as a fluid of virtual gravitational dipoles. Following this hypothesis, we present the first indications that dark matter may not exist and that the phenomena for which it was invoked might be explained by the gravitational polarization of the quantum vacuum by the known baryonic matter.

  12. High time resolution observations of the polar stratosphere and mesosphere using a ground-based 230-250 GHz microwave radiometer

    NASA Astrophysics Data System (ADS)

    Newnham, D. A.; Espy, P. J.; Clilverd, M. A.; Maxfield, D. J.; Hartogh, P.; Holmén, K.; Blindheim, S.; Horne, R. B.

    2012-04-01

    Microwave radiometry is used to measure thermal emission by the Doppler- and pressure-broadened molecular rotational lines of atmospheric gases, from which vertical abundance profiles can be determined. Since solar radiation is not required for the measurement, the technique has the advantage that continuous observations are possible including throughout the polar winter. We describe the development of a passive microwave radiometer [Espy, P. J., P. Hartogh, and K. Holmen (2006), Proc. SPIE, 6362, 63620P, doi:10.1117/12.688953] for ground-based remote sensing of the polar middle atmosphere. The instrument measures nitric oxide (NO), ozone (O3), and carbon monoxide (CO) vertical profiles over the altitude range 35-90 km with time resolution as high as 15 minutes, allowing the diurnal variability of trace chemical species to be investigated. Heterodyne detection of atmospheric emission at 230 GHz and 250 GHz (wavelength ~1.25 mm) with a receiver noise temperature of 300 K is achieved using a superconductor-insulator-superconductor (SIS) mixer cooled to 4 K. The down-converted signals at 1.35 GHz and 2.10 GHz are analysed using both a moderate-resolution (28 kHz, 220 MHz bandwidth) and a high-resolution (14 kHz, 40 MHz bandwidth) chirp-transform spectrometer (CTS). The instrument was operated semi-autonomously at Troll station (72° 01'S 02° 32'E, 1270 m above sea level), Antarctica during 2008-10 and at the Arctic LIDAR Observatory for Middle Atmosphere Research (ALOMAR, 69° 16'N, 16° 00'E, 380 m above sea level), northern Norway during 2011-12. NO volume mixing ratio (VMR) profiles have been inverted from calibrated brightness temperature spectra of the NO line centred at 250.796 GHz, observed above Troll station, using the Microwave Observation Line Estimation and Retrieval (MOLIERE) version 5 code. A priori pressure, temperature, ozone, water vapour, and NO profiles above 30 km were calculated using the Sodankylä Ion and Neutral Chemistry (SIC, version 6

  13. Ionization and NO production in the polar mesosphere during high-speed solar wind streams: model validation and comparison with NO enhancements observed by Odin-SMR

    NASA Astrophysics Data System (ADS)

    Kirkwood, S.; Osepian, A.; Belova, E.; Urban, J.; Perot, K.; Sinha, A. K.

    2015-05-01

    Precipitation of high-energy electrons (EEP) into the polar middle atmosphere is a potential source of significant production of odd nitrogen, which may play a role in stratospheric ozone destruction and in perturbing large-scale atmospheric circulation patterns. High-speed streams of solar wind (HSS) are a major source of energization and precipitation of electrons from the Earth's radiation belts, but it remains to be determined whether these electrons make a significant contribution to the odd-nitrogen budget in the middle atmosphere when compared to production by solar protons or by lower-energy (auroral) electrons at higher altitudes, with subsequent downward transport. Satellite observations of EEP are available, but their accuracy is not well established. Studies of the ionization of the atmosphere in response to EEP, in terms of cosmic-noise absorption (CNA), have indicated an unexplained seasonal variation in HSS-related effects and have suggested possible order-of-magnitude underestimates of the EEP fluxes by the satellite observations in some circumstances. Here we use a model of ionization by EEP coupled with an ion chemistry model to show that published average EEP fluxes, during HSS events, from satellite measurements (Meredith et al., 2011), are fully consistent with the published average CNA response (Kavanagh et al., 2012). The seasonal variation of CNA response can be explained by ion chemistry with no need for any seasonal variation in EEP. Average EEP fluxes are used to estimate production rate profiles of nitric oxide between 60 and 100 km heights over Antarctica for a series of unusually well separated HSS events in austral winter 2010. These are compared to observations of changes in nitric oxide during the events, made by the sub-millimetre microwave radiometer on the Odin spacecraft. The observations show strong increases of nitric oxide amounts between 75 and 90 km heights, at all latitudes poleward of 60° S, about 10 days after the

  14. Equation of state of hot polarized nuclear matter and heavy-ion fusion reactions

    SciTech Connect

    Ghodsi, O. N.; Gharaei, R.

    2011-08-15

    We employ the equation of state of hot polarized nuclear matter to simulate the repulsive force caused by the incompressibility effects of nuclear matter in the fusion reactions of heavy colliding ions. The results of our studies reveal that temperature effects of compound nuclei have significant importance in simulating the repulsive force on the fusion reactions for which the temperature of the compound nucleus increases up to about 2 MeV. Since the equation of state of hot nuclear matter depends upon the density and temperature of the nuclear matter, it has been suggested that, by using this equation of state, one can simulate simultaneously both the effects of the precompound nucleons' emission and the incompressibility of nuclear matter to calculate the nuclear potential in fusion reactions within a static formalism such as the double-folding (DF) model.

  15. Radiative transfer model for the computation of radiance and polarization in an ocean-atmosphere system: polarization properties of suspended matter for remote sensing.

    PubMed

    Chami, M; Santer, R; Dilligeard, E

    2001-05-20

    A radiative transfer code termed OSOA for the ocean-atmosphere system that is able to predict the total and the polarized signals has been developed. The successive-orders-of-scattering method is used. The air-water interface is modeled as a planar mirror. Four components grouped by their optical properties, pure seawater, phytoplankton, nonchlorophyllose matter, and yellow substances, are included in the water column. Models are validated through comparisons with standard models. The numerical accuracy of the method is better than 2%; high computational efficiency is maintained. The model is used to study the influence of polarization on the detection of suspended matter. Polarizing properties of hydrosols are discussed: phytoplankton cells exhibit weak polarization and small inorganic particles, which are strong backscatterers, contribute appreciably to the polarized signal. Therefore the use of the polarized signal to extract the sediment signature promises good results. Also, polarized radiance could improve characterization of aerosols when open ocean waters are treated. PMID:18357248

  16. Correlation of soil and sediment organic matter polarity to aqueous sorption of nonionic compounds

    USGS Publications Warehouse

    Kile, D.E.; Wershaw, R. L.; Chiou, C.T.

    1999-01-01

    Polarities of the soiL/sediment organic matter (SOM) in 19 soil and 9 freshwater sediment sam pies were determined from solid-state 13C-CP/MAS NMR spectra and compared with published partition coefficients (K(oc)) of carbon tetrachloride (CT) from aqueous solution. Nondestructive analysis of whole samples by solid-state NMR permits a direct assessment of the polarity of SOM that is not possible by elemental analysis. The percent of organic carbon associated with polar functional groups was estimated from the combined fraction of carbohydrate and carboxylamide-ester carbons. A plot of the measured partition coefficients (K(oc)) of carbon tetrachloride (CT) vs. percent polar organic carbon (POC) shows distinctly different populations of soils and sediments as well as a roughly inverse trend among the soil/sediment populations. Plots of K(oc) values for CT against other structural group carbon fractions did not yield distinct populations. The results indicate that the polarity of SOM is a significant factor in accounting for differences in K(oc) between the organic matter in soils and sediments. The alternate direct correlation of the sum of aliphatic and aromatic structural carbons with K(oc) illustrates the influence of nonpolar hydrocarbon on solute partition interaction. Additional elemental analysis data of selected samples further substantiate the effect of the organic matter polarity on the partition efficiency of nonpolar solutes. The separation between soil and sediment samples based on percent POC reflects definite differences of the properties of soil and sediment organic matters that are attributable to diagenesis.Polarities of the soil/sediment organic matter (SOM) in 19 soil and 9 freshwater sediment samples were determined from solid-state 13C-CP/MAS NMR spectra and compared with published partition coefficients (Koc) of carbon tetrachloride (CT) from aqueous solution. Nondestructive analysis of whole samples by solid-state NMR permits a direct

  17. Methanogenesis, Mesospheric Clouds, and Global Habitability

    NASA Technical Reports Server (NTRS)

    Pueschel, Rudolf F.; Condon, Estelle P. (Technical Monitor)

    2000-01-01

    Hyperthermophilic methanogens can exist in a deep hot biosphere up to 110 C, or 10 km deep. Methane (CH4) itself is thermodynamically stable to depths of 300 km. Geologic (microbial plus abiogenic thermal) methane is transported upward, attested to by its association with helium, to form petroleum pools. Near or at the surface, geologic CH4 mixes with other natural and with anthropogenic CH4 yielding annual emissions into the atmosphere of 500 Tg, of which 200 Tg are natural and 300 Tg are man-made. The atmospheric lifetime of CH4, a greenhouse gas 20 times more effective than CO2 in raising global temperatures, is approximately 10 years. It is removed from the atmosphere mainly by reactions with hydroxyl radical (OH) to form CO2, but also by dry soil and by conversion to H2O in the stratosphere and middle atmosphere. A sudden rise in atmospheric temperatures by 9-12 C some 55 million years ago has been explained by the release in a few thousand years of three trillion tons of CH4 out of 15 trillion tons that had formed beneath the sea floor. What prevented this CH4-induced greenhouse effect from running away? An analog to the CH4-burp of 55 million years ago is the CH4-doubling over the past century which resulted in a increase in upper level H2O from 4.3 ppmv to 6 ppmv. This 30% increase in H2O vapor yielded a tenfold increase in brightness of polar mesospheric clouds because of a strong dependence of the ice particle nucleation rate on the water saturation ratios. Models show that at a given temperature the optical depth of mesospheric clouds scales as [H2O]beta with beta varying between 4 and 8. Radiative transfer tools applied to mesospheric particles suggest that an optical depth of approximately one, or 1000 times the current mesospheric cloud optical depth, would result in tropospheric cooling of about 10 K. Assuming beta=6, a thousandfold increase in optical thickness would require a three-fold increase of H2O, or a 20-fold increase of CH4. At the current

  18. Can spin-polarized photoemission measure spin properties in condensed matter?

    PubMed

    Osterwalder, Jürg

    2012-05-01

    Photoemitted electrons move in a vacuum; their quantum state can be completely characterized in terms of energy, momentum and spin polarization by spin-polarized photoemission experiments. A review article in this issue by Heinzmann and Dil (2012 J. Phys.: Condens. Matter 24 173001) considers whether the measured spin properties, i.e. the magnitude and direction of the spin polarization vector, can be traced back to the quantum state from which these electrons originate. The careful conclusion is that they can, which is highly relevant in view of the current interest in these experiments and their application to topological insulators, where the spin-orbit interaction produces spin-polarized surface states. PMID:22481567

  19. Spin-polarized neutron matter: Critical unpairing and BCS-BEC precursor

    NASA Astrophysics Data System (ADS)

    Stein, Martin; Sedrakian, Armen; Huang, Xu-Guang; Clark, John W.

    2016-01-01

    We obtain the critical magnetic field required for complete destruction of S -wave pairing in neutron matter, thereby setting limits on the pairing and superfluidity of neutrons in the crust and outer core of magnetars. We find that for fields B ≥1017 G the neutron fluid is nonsuperfluid—if weaker spin 1 superfluidity does not intervene—a result with profound consequences for the thermal, rotational, and oscillatory behavior of magnetars. Because the dineutron is not bound in vacuum, cold dilute neutron matter cannot exhibit a proper BCS-BEC crossover. Nevertheless, owing to the strongly resonant behavior of the n n interaction at low densities, neutron matter shows a precursor of the BEC state, as manifested in Cooper-pair correlation lengths being comparable to the interparticle distance. We make a systematic quantitative study of this type of BCS-BEC crossover in the presence of neutron fluid spin polarization induced by an ultrastrong magnetic field. We evaluate the Cooper-pair wave function, quasiparticle occupation numbers, and quasiparticle spectra for densities and temperatures spanning the BCS-BEC crossover region. The phase diagram of spin-polarized neutron matter is constructed and explored at different polarizations.

  20. Effects of polar and nonpolar groups on the solubility of organic compounds in soil organic matter

    USGS Publications Warehouse

    Chiou, C.T.; Kile, D.E.

    1994-01-01

    Vapor sorption capacities on a high-organic-content peat, a model for soil organic matter (SOM), were determined at room temperature for the following liquids: n-hexane, 1,4-dioxane, nitroethane, acetone, acetonitrile, 1-propanol, ethanol, and methanol. The linear organic vapor sorption is in keeping with the dominance of vapor partition in peat SOM. These data and similar results of carbon tetrachloride (CT), trichloroethylene (TCE), benzene, ethylene glycol monoethyl ether (EGME), and water on the same peat from earlier studies are used to evaluate the effect of polarity on the vapor partition in SOM. The extrapolated liquid solubility from the vapor isotherm increases sharply from 3-6 wt % for low-polarity liquids (hexane, CT, and benzene) to 62 wt % for polar methanol and correlates positively with the liquid's component solubility parameters for polar interaction (??P) and hydrogen bonding (??h). The same polarity effect may be expected to influence the relative solubilities of a variety of contaminants in SOM and, therefore, the relative deviations between the SOM-water partition coefficients (Kom) and corresponding octanol-water partition coefficients (Kow) for different classes of compounds. The large solubility disparity in SOM between polar and nonpolar solutes suggests that the accurate prediction of Kom from Kow or Sw (solute water solubility) would be limited to compounds of similar polarity.

  1. Temperature trends in the mesosphere

    NASA Astrophysics Data System (ADS)

    Lübken, Franz-Josef; Berger, Uwe

    2013-04-01

    We have performed trend studies in the mesosphere in the period 1961-2009 with LIMA (Leibniz-Institute Middle Atmosphere model) which is based on ECMWF below approximately 40 km and adapts temporal variations of CO2 and O3 according to observations. There is general agreement between LIMA and observations. Temperatures in the mesosphere/lower thermosphere vary non-uniformly with time, mainly due to the influence of ozone. We have therefore separated the influence of CO2(t) and O3(t) when determining trends. It is important to distinguish between trends on pressure altitudes, zp, and geometric altitudes, zgeo, where the latter includes the effect of shrinking due to cooling at lower heights. Maximum total temperature trends reach approximately -1,3 K/dec at zp ~60 km and -1.8 K/dec at zgeo ~70 km, respectively. Carbon dioxide is the main driver of these trends in the mesosphere, whereas ozone contributes approximately one third, both on geometric and pressure heights. Depending on the time period chosen, the ozone effect on trends can be significantly smaller or larger. Temperature trends on geometric and pressure altitudes can differ by as much as -0.9 K/dec in the mesosphere. The altitudes of pressure levels in the mesosphere decrease up to several hundred meters. The shift maximizes at mesopause levels where it accumulates to more than 1 km. Most of the shrinking occurs in the mesosphere and a smaller fraction (~20%) in the stratosphere. For the first time, we have performed long term runs with LIMA applying the 20th Century Reanalysis from NCEP/NCAR dating back to 1871. Again, trends are non-uniform with time. Since the late 19th century temperatures in the mesosphere have dropped by approximately 5-7 K on pressure altitudes, and up to 10-12 K on geometric altitudes. This is much more then typical trends in the troposphere and stratosphere. It is therefore justified to summarize that the mesosphere (at least in summer and at middle latitudes) reacts

  2. Inertio Gravity Waves in the Upper Mesosphere

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G.; Talaat, E. L.; Porter, H. S.; Chan, K. L.

    2003-01-01

    In the polar region of the upper mesosphere, horizontal wind oscillations have been observed with periods around 10 hours (Hernandez et al., 1992). Such waves are generated in our Numerical Spectral Model (NSM) and appear to be inertio gravity waves (IGW). Like the planetary waves (PW) in the model, the IGWs are generated by instabilities that arise in the mean zonal circulation. In addition to stationary waves for m = 0, eastward and westward propagating waves for m = 1 to 4 appear above 70 km that grow in magnitude up to about 110 km, having periods between 9 and 11 hours. The m = 1 westward propagating IGWs have the largest amplitudes, which can reach at the poles 30 m/s. Like PWs, the IGWs are intermittent but reveal systematic seasonal variations, with the largest amplitudes occurring generally in winter and spring. The IGWs propagate upward with a vertical wavelength of about 20 km.

  3. Reverse-phase HPLC method for measuring polarity distributions of natural organic matter.

    PubMed

    Namjesnik-Dejanovic, Ksenija; Cabaniss, Stephen E

    2004-02-15

    A reverse-phase high-pressure liquid chromatography (RP-HPLC) method was developed to measure the polarity distribution of natural organic matter (NOM) samples. The polarity distribution is obtained by calibrating an octadecyl bonded silica phase column and polar eluent with compounds of known octanol-water partition coefficient (Kow) and using this calibration curve to transform NOM retention times into an equivalent Kow. Polarity distributions treat the NOM samples as a complex mixture rather than summarizing the polarity in a single number. The method is sensitive, with UV detection allowing quantitation of samples with <5 mg of C/L. Individual chromatograms are acquired in <20 min, allowing much faster analysis on smaller samples than XAD resin separation or 13C NMR. Polarity distributions of 10 representative NOM isolates and 2 whole water samples indicate that NOM is generally hydrophilic in nature (log Kow < 2), although XAD-8 isolates are more hydrophobic than RO isolates from the same source. Hydrophilicity, as indicated by recovery from the HPLC column, is correlated to the elemental oxygen/carbon ratio but does not correlate strongly with molecular weight or 13C NMR aromaticity. PMID:14998025

  4. Charging of mesospheric particles - Implications for electron density and particle coagulation

    NASA Technical Reports Server (NTRS)

    Jensen, Eric J.; Thomas, Gary E.

    1991-01-01

    The relationship between N(e) and mesospheric aerosols near the mesopause is studied. The full distribution of charges on mesospheric aerosols is calculated, including dust and ice particles with radii ranging from 1 to 400 nm. The N(e) and ion density N(i) are obtained and ionization height profiles are calculated. The effects of dust and ice particles on N(e) and N(i) are studied for a wide range of assumed conditions. The results indicate that aerosol concentrations associated with visible polar mesospheric clouds are unlikely to cause a severe N(e) depletion. The pronounced 'bite-out' of N(e) at about 87 km in the summertime may be caused by a large concentration of small ice particles in a narrow cold layer near the mesosphere. Net negative charge on mesospheric aerosols may severely inihibit coagulation, so that mesospheric dust would not grow significantly. A higher supersaturation with respect to water vapor would be needed for heterogeneous nucleation of ice crystals.

  5. Attosecond nonlinear polarization and light–matter energy transfer in solids

    NASA Astrophysics Data System (ADS)

    Sommer, A.; Bothschafter, E. M.; Sato, S. A.; Jakubeit, C.; Latka, T.; Razskazovskaya, O.; Fattahi, H.; Jobst, M.; Schweinberger, W.; Shirvanyan, V.; Yakovlev, V. S.; Kienberger, R.; Yabana, K.; Karpowicz, N.; Schultze, M.; Krausz, F.

    2016-06-01

    Electric-field-induced charge separation (polarization) is the most fundamental manifestation of the interaction of light with matter and a phenomenon of great technological relevance. Nonlinear optical polarization produces coherent radiation in spectral ranges inaccessible by lasers and constitutes the key to ultimate-speed signal manipulation. Terahertz techniques have provided experimental access to this important observable up to frequencies of several terahertz. Here we demonstrate that attosecond metrology extends the resolution to petahertz frequencies of visible light. Attosecond polarization spectroscopy allows measurement of the response of the electronic system of silica to strong (more than one volt per ångström) few-cycle optical (about 750 nanometres) fields. Our proof-of-concept study provides time-resolved insight into the attosecond nonlinear polarization and the light–matter energy transfer dynamics behind the optical Kerr effect and multi-photon absorption. Timing the nonlinear polarization relative to the driving laser electric field with sub-30-attosecond accuracy yields direct quantitative access to both the reversible and irreversible energy exchange between visible–infrared light and electrons. Quantitative determination of dissipation within a signal manipulation cycle of only a few femtoseconds duration (by measurement and ab initio calculation) reveals the feasibility of dielectric optical switching at clock rates above 100 terahertz. The observed sub-femtosecond rise of energy transfer from the field to the material (for a peak electric field strength exceeding 2.5 volts per ångström) in turn indicates the viability of petahertz-bandwidth metrology with a solid-state device.

  6. Attosecond nonlinear polarization and light-matter energy transfer in solids.

    PubMed

    Sommer, A; Bothschafter, E M; Sato, S A; Jakubeit, C; Latka, T; Razskazovskaya, O; Fattahi, H; Jobst, M; Schweinberger, W; Shirvanyan, V; Yakovlev, V S; Kienberger, R; Yabana, K; Karpowicz, N; Schultze, M; Krausz, F

    2016-06-01

    Electric-field-induced charge separation (polarization) is the most fundamental manifestation of the interaction of light with matter and a phenomenon of great technological relevance. Nonlinear optical polarization produces coherent radiation in spectral ranges inaccessible by lasers and constitutes the key to ultimate-speed signal manipulation. Terahertz techniques have provided experimental access to this important observable up to frequencies of several terahertz. Here we demonstrate that attosecond metrology extends the resolution to petahertz frequencies of visible light. Attosecond polarization spectroscopy allows measurement of the response of the electronic system of silica to strong (more than one volt per ångström) few-cycle optical (about 750 nanometres) fields. Our proof-of-concept study provides time-resolved insight into the attosecond nonlinear polarization and the light-matter energy transfer dynamics behind the optical Kerr effect and multi-photon absorption. Timing the nonlinear polarization relative to the driving laser electric field with sub-30-attosecond accuracy yields direct quantitative access to both the reversible and irreversible energy exchange between visible-infrared light and electrons. Quantitative determination of dissipation within a signal manipulation cycle of only a few femtoseconds duration (by measurement and ab initio calculation) reveals the feasibility of dielectric optical switching at clock rates above 100 terahertz. The observed sub-femtosecond rise of energy transfer from the field to the material (for a peak electric field strength exceeding 2.5 volts per ångström) in turn indicates the viability of petahertz-bandwidth metrology with a solid-state device. PMID:27251280

  7. Solar mesosphere explorer: Experiment description

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The Solar Mesosphere Explorer (SME) satellite experiments will provide a comprehensive study of atmospheric ozone and the processes which form and destroy it. Five instruments to be carried on the spacecraft will measure the ozone density and altitude distribution, monitor the incoming solar radiation, and measure other atmospheric constituents which affect ozone. The investigative approach concept, methods and procedures, preflight studies, and orbits and mission lifetime are presented. Descriptions of the instruments are also presented.

  8. Accelerating Nuclear Magnetic Resonance (NMR) Analysis of Soil Organic Matter with Dynamic Nuclear Polarization (DNP) Enhancement

    NASA Astrophysics Data System (ADS)

    Normand, A. E.; Smith, A. N.; Long, J. R.; Reddy, K. R.

    2014-12-01

    13C magic angle spinning (MAS) solid state Nuclear Magnetic Resonance (ssNMR) has become an essential tool for discerning the chemical composition of soil organic matter (SOM). However, the technique is limited due to the inherent insensitivity of NMR resulting in long acquisition times, especially for low carbon (C) soil. The pursuits of higher magnetic fields or concentrating C with hydrofluoric acid are limited solutions for signal improvement. Recent advances in dynamic nuclear polarization (DNP) have addressed the insensitivity of NMR. DNP utilizes the greater polarization of an unpaired electron in a given magnetic field and transfers that polarization to an NMR active nucleus of interest via microwave irradiation. Signal enhancements of up to a few orders of magnitude have been achieved for various DNP experiments. In this novel study, we conduct DNP 13C cross-polarization (CP) MAS ssNMR experiments of SOM varying in soil C content and chemical composition. DNP signal enhancements reduce the experiment run time allowing samples with low C to be analyzed in hours rather than days. We compare 13C CP MAS ssNMR of SOM with multiple magnetic field strengths, hydrofluoric acid treatment, and novel DNP approaches. We also explore DNP surface enhanced NMR Spectroscopy (SENP) to determine the surface chemistry of SOM. The presented results and future DNP MAS ssNMR advances will lead to further understanding of the nature and processes of SOM.

  9. Connection between the midlatitude mesosphere and sudden stratospheric warmings as measured by Rayleigh-scatter lidar

    NASA Astrophysics Data System (ADS)

    Sox, Leda; Wickwar, Vincent B.; Fish, Chad S.; Herron, Joshua P.

    2016-05-01

    While the mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are much more sparse. The Rayleigh-scatter lidar system, which operated at the Center for Atmospheric and Space Sciences on the campus of Utah State University (41.7°N, 111.8°W), collected a very dense set of observations, from 1993 to 2004, over a 45-90 km altitude range. This paper focuses on Rayleigh lidar temperatures derived during the six major SSW events that occurred during the 11 year period when the lidar was operating and aims to characterize the local response to these midlatitude SSW events. In order to determine the characteristics of these mesospheric temperature anomalies, comparisons were made between the temperatures from individual nights during a SSW event and a climatological temperature profile. An overall disturbance pattern was observed in the mesospheric temperatures associated with SSW events, including coolings in the upper mesosphere and warmings in the upper stratosphere and lower mesosphere, both comparable to those seen at polar latitudes.

  10. Antimatter and Dark Matter Search in Space: BESS-Polar Results

    NASA Technical Reports Server (NTRS)

    Mitchell, John W.; Yamamoto, Akira

    2009-01-01

    The apex of the Balloon-borne Experiment with a Superconducting Spectrometer program was reached with the Antarctic flight of BESS-Polar II, during the 2007-2008 Austral Summer, that obtained 24.5 days of data on over 4.7 billion cosmic-ray events. The US-Japan BESS Collaboration uses elementary particle measurements to study the early Universe and provides fundamental data on the spectra of light cosmic-ray elements and isotopes. BESS measures the energy spectra of cosmic-ray antiprotons to investigate signatures of possible exotic sources, such as dark-matter candidates, and searches for heavier anti-nuclei that might reach Earth from antimatter domains formed during symmetry breaking processes in the early Universe. Since 1993, BESS has carried out eleven high-latitude balloon flights, two of long duration, that together have defined the study of antiprotons below about 4 GeV, provided standard references for light element and isotope spectra, and set the most sensitive limits on the existence of anti-deuterons and anti-helium, The BESS-Polar II flight took place at Solar Minimum, when the sensitivity of the low-energy antiproton measurements to a primary source is greatest. The rich BESS-Polar II dataset more than doubles the combined data from all earlier BESS flights and has 10-20 times the statistics of BESS data from the previous Solar Minimum. Here, we summarize the scientific results of BESS program, focusing on the results obtained using data from the long-duration flights of BESS-Polar I (2004) and BESS-Polar II.

  11. Cisplatin loaded albumin mesospheres for lung cancer treatment

    PubMed Central

    Lee, Hung-Yen; Mohammed, Kamal A; Goldberg, Eugene P; Kaye, Frederic; Nasreen, Najmunnisa

    2015-01-01

    The low solubility of cisplatin in aqueous solution limits the treatment effectiveness and the application of cisplatin in various kinds of drug-eluting devices. Although cisplatin has a high solubility in Dimethyl sulfoxide (DMSO), the toxicity of cisplatin can be greatly reduced while dissolved in DMSO. In this study, the solid powder of cisplatin-loaded albumin mesospheres (CDDP/DMSO-AMS), in a size range of 1 to 10 µm, were post-loaded with cisplatin and showed high cisplatin content (16% w/w) and effective cytotoxicity to lung cancer cells. Cisplatin were efficiently absorbed into the albumin mesospheres (AMS) in DMSO and, most importantly, the toxicity of cisplatin was remained at 100% after the loading process. This CDDP/DMSO-AMS was designed for the intratumoral injection through the bronchoscopic catheter or dry powder inhalation (DPI) due to its high stability in air or in solution. This CDDP/DMSO-AMS showed a fast cisplatin release within 24 hours. In the in vitro study, CDDP/DMSO-AMS showed high effectiveness on killing the lung cancer cells including the non-small cell lung cancer (NCL-H23 and A549), malignant mesothelioma (CRL-2081) and the mouse lung carcinoma (Lewis lung carcinoma) cell lines. The albumin based mesospheres provide an ideal loading matrix for cisplatin and other metal-based drugs due to the high swelling degree and fast uptake rate in the organic solvents with high polarity. In addition, to investigate the effects of polysaccharides, such as chitosan and chondroitin, on enhancing loading efficiency and lasting cytotoxicity of cisplatin, the polysaccharide-modified albumin mesospheres were synthesized and loaded with cisplatin in this study. PMID:25973300

  12. Cisplatin loaded albumin mesospheres for lung cancer treatment.

    PubMed

    Lee, Hung-Yen; Mohammed, Kamal A; Goldberg, Eugene P; Kaye, Frederic; Nasreen, Najmunnisa

    2015-01-01

    The low solubility of cisplatin in aqueous solution limits the treatment effectiveness and the application of cisplatin in various kinds of drug-eluting devices. Although cisplatin has a high solubility in Dimethyl sulfoxide (DMSO), the toxicity of cisplatin can be greatly reduced while dissolved in DMSO. In this study, the solid powder of cisplatin-loaded albumin mesospheres (CDDP/DMSO-AMS), in a size range of 1 to 10 µm, were post-loaded with cisplatin and showed high cisplatin content (16% w/w) and effective cytotoxicity to lung cancer cells. Cisplatin were efficiently absorbed into the albumin mesospheres (AMS) in DMSO and, most importantly, the toxicity of cisplatin was remained at 100% after the loading process. This CDDP/DMSO-AMS was designed for the intratumoral injection through the bronchoscopic catheter or dry powder inhalation (DPI) due to its high stability in air or in solution. This CDDP/DMSO-AMS showed a fast cisplatin release within 24 hours. In the in vitro study, CDDP/DMSO-AMS showed high effectiveness on killing the lung cancer cells including the non-small cell lung cancer (NCL-H23 and A549), malignant mesothelioma (CRL-2081) and the mouse lung carcinoma (Lewis lung carcinoma) cell lines. The albumin based mesospheres provide an ideal loading matrix for cisplatin and other metal-based drugs due to the high swelling degree and fast uptake rate in the organic solvents with high polarity. In addition, to investigate the effects of polysaccharides, such as chitosan and chondroitin, on enhancing loading efficiency and lasting cytotoxicity of cisplatin, the polysaccharide-modified albumin mesospheres were synthesized and loaded with cisplatin in this study. PMID:25973300

  13. Role of polarity fractions of effluent organic matter in binding and toxicity of silver and copper.

    PubMed

    Yoo, Jisu; Shim, Taeyong; Hur, Jin; Jung, Jinho

    2016-11-01

    This study evaluates the effect of the physicochemical properties of effluent organic matter (EfOM) from industrial and sewage wastewater treatment plants (WWTPs) on the binding and toxicity of Ag and Cu. EfOM was isolated into hydrophobic, transphilic, and hydrophilic fractions depending on its polarity, and was characterized by elemental, specific ultraviolet absorbance, and fluorescence excitation-emission matrix analyses. Our results suggest that the EfOM consists of microbially derived non-humic substances that have lower aromaticity than the Suwannee River natural organic matter (SR-NOM). The Freundlich model was better at explaining the binding of Ag and Cu onto both SR-NOM and EfOM than the Langmuir model. In particular, the hydrophilic fractions of sewage EfOM showed higher binding capacities and affinities for Ag and Cu than the corresponding hydrophobic fractions, resulting in better reduction of the acute toxicity of Ag and Cu towards Daphnia magna. However, in the case of both SR-NOM and industrial EfOM, the hydrophobic fractions were more efficient at reducing metal toxicity. These findings suggest that the EfOM has different physicochemical properties compared with NOM and that the binding and toxicity of heavy metals are largely dependent on the polarity fractions of EfOM. PMID:27318731

  14. Diurnal variation of mesospheric ozone

    NASA Astrophysics Data System (ADS)

    Vaughan, G.

    1982-03-01

    Four Petrel rockets were flown from South Uist on October 2, 1979, to investigate the ozone concentration variation predicted by photochemical models between day and night in the mesosphere by means of interference filters that defined an approximately 10 nm bandwidth. The first two rockets contained photometers with wavebands centered at 265 and 290 nm, while the last two employed a single waveband at 265 nm. Results show significant diurnal variation above 54 km, which exceeds a factor of 2 above 65 km and reaches a factor of 10 between night and sunrise at 90 km.

  15. Missing driver in the Sun-Earth connection from energetic electron precipitation impacts mesospheric ozone.

    PubMed

    Andersson, M E; Verronen, P T; Rodger, C J; Clilverd, M A; Seppälä, A

    2014-01-01

    Energetic electron precipitation (EEP) from the Earth's outer radiation belt continuously affects the chemical composition of the polar mesosphere. EEP can contribute to catalytic ozone loss in the mesosphere through ionization and enhanced production of odd hydrogen. However, the long-term mesospheric ozone variability caused by EEP has not been quantified or confirmed to date. Here we show, using observations from three different satellite instruments, that EEP events strongly affect ozone at 60-80 km, leading to extremely large (up to 90%) short-term ozone depletion. This impact is comparable to that of large, but much less frequent, solar proton events. On solar cycle timescales, we find that EEP causes ozone variations of up to 34% at 70-80 km. With such a magnitude, it is reasonable to suspect that EEP could be an important part of solar influence on the atmosphere and climate system. PMID:25312693

  16. Missing driver in the Sun–Earth connection from energetic electron precipitation impacts mesospheric ozone

    PubMed Central

    Andersson, M. E.; Verronen, P. T.; Rodger, C. J.; Clilverd, M. A.; Seppälä, A.

    2014-01-01

    Energetic electron precipitation (EEP) from the Earth’s outer radiation belt continuously affects the chemical composition of the polar mesosphere. EEP can contribute to catalytic ozone loss in the mesosphere through ionization and enhanced production of odd hydrogen. However, the long-term mesospheric ozone variability caused by EEP has not been quantified or confirmed to date. Here we show, using observations from three different satellite instruments, that EEP events strongly affect ozone at 60–80 km, leading to extremely large (up to 90%) short-term ozone depletion. This impact is comparable to that of large, but much less frequent, solar proton events. On solar cycle timescales, we find that EEP causes ozone variations of up to 34% at 70–80 km. With such a magnitude, it is reasonable to suspect that EEP could be an important part of solar influence on the atmosphere and climate system. PMID:25312693

  17. Missing driver in the Sun-Earth connection from energetic electron precipitation impacts mesospheric ozone

    NASA Astrophysics Data System (ADS)

    Andersson, M. E.; Verronen, P. T.; Rodger, C. J.; Clilverd, M. A.; Seppälä, A.

    2014-10-01

    Energetic electron precipitation (EEP) from the Earth’s outer radiation belt continuously affects the chemical composition of the polar mesosphere. EEP can contribute to catalytic ozone loss in the mesosphere through ionization and enhanced production of odd hydrogen. However, the long-term mesospheric ozone variability caused by EEP has not been quantified or confirmed to date. Here we show, using observations from three different satellite instruments, that EEP events strongly affect ozone at 60-80 km, leading to extremely large (up to 90%) short-term ozone depletion. This impact is comparable to that of large, but much less frequent, solar proton events. On solar cycle timescales, we find that EEP causes ozone variations of up to 34% at 70-80 km. With such a magnitude, it is reasonable to suspect that EEP could be an important part of solar influence on the atmosphere and climate system.

  18. The Tromsø programme of in situ and sample return studies of mesospheric nanoparticles

    NASA Astrophysics Data System (ADS)

    Havnes, O.; Antonsen, T.; Hartquist, T. W.; Fredriksen, Å.; Plane, J. M. C.

    2015-05-01

    We review some of the work performed over the past two decades with rocket-borne detectors to study mesospheric dust or nanoparticles, including meteoric smoke particles (MSPs) and water ice particles in the mesosphere. We focus on regions in which noctilucent clouds (NLCs) and polar summer mesospheric echoes (PMSEs) occur. Our primary emphasis is on several detectors designed, built and used by the Tromsø group and collaborators, and results obtained with them. These include the DUSTY, MUDD and ICON probes, the latter for which the results of laboratory tests are presented. However, we also mention, but do not address in detail, some of the investigations conducted by others and describe very briefly our preparations for sample return measurements. We consider the importance of accounting for the secondary charging occurring in detectors as nanoparticles strike them, evidence that MSPs fill up to several per cent of the volume in icy particles and measurements of the size distribution of the MSPs.

  19. Investigating asymmetries in mesospheric gravity wave propagation at high-latitudes

    NASA Astrophysics Data System (ADS)

    Taylor, M. J.; Zhao, Y.; Ward, R.; Martin, T.; Pautet, P.; Dyrland, M. E.; Nielsen, K.; Jarvis, M. J.; Moffat-Griffin, T.; Randall, C. E.; Lumpe, J. D.; Bailey, S. M.; Russell, J. M.

    2012-12-01

    A combination of ground based imaging of gravity waves in the mesospheric OH emission (peak altitude ~87 km) and satellite measurements of waves as detected in extensive polar mesospheric clouds, PMC's (mean altitude ~83 km) has been used to investigate summer-winter wave properties in both the Northern and Southern polar regions. Wintertime all-sky image data primarily from two sites (Halley and Rothera) on the Antarctic coast, obtained as part of a collaborative program with British Antarctic Survey, and from the Kjell Henriksen Observatory (KHO) Svalbard in the high Arctic, have been utilized to determine the dominant characteristics of both short and medium scale gravity waves (observed periods up to ~1 hour). These new results, which show distinct asymmetries in their propagation headings, are compared with recent summertime gravity wave measurements using PMC data from the Cloud Imaging and Particle Size (CIPS) experiment on the NASA Aeronomy of Ice in the Mesosphere (AIM) satellite. Our Southern Hemisphere results reveal novel evidence for strong preferences for zonal wave motions particularly for the smaller scale (<100 km horizontal wavelength) suggesting a significant pattern for meridional filtering throughout the Antarctic continent. In contrast, the medium-scale waves exhibited a consistent but quite different motion field. These new results are compared with recent Northern Hemisphere measurements to further investigate polar wave dynamics in the Mesosphere and Lower Thermosphere (MLT) region (~80-100 km).

  20. Mesospheric Dynamical Changes Induced by the Solar Proton Events in October-November 2003

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Roble, Raymond G.; Fleming, Eric L.

    2007-01-01

    The very large solar storms in October-November 2003 caused solar proton events (SPEs) at the Earth that impacted the upper atmospheric polar cap regions. The Thermosphere Ionosphere Mesosphere Electrodynamic General Circulation Model (TIME-GCM) was used to study the atmospheric dynamical influence of the solar protons that occurred in Oct-Nov 2003, the fourth largest period of SPEs measured in the past 40 years. The highly energetic solar protons caused ionization, as well as dissociation processes, and ultimately produced odd hydrogen (HOx) and odd nitrogen (NOy). Significant short-lived ozone decreases (10-70%) followed these enhancements of HOx and NOy and led to a cooling of most of the lower mesosphere. This cooling caused an atmospheric circulation change that led to adiabatic heating of the upper mesosphere. Temperature changes up to plus or minus 2.6 K were computed as well as wind (zonal, meridional, vertical) perturbations up to 20-25% of the background winds as a result of 22 the solar protons. The solar proton-induced mesospheric temperature and wind perturbations diminished over a period of 4-6 weeks after the SPEs. The Joule heating in the mesosphere, induced by the solar protons, was computed to be relatively insignificant for these solar storms with most of the temperature and circulation perturbations caused by ozone depletion in the sunlit hemisphere.

  1. Analysis of Trends at Mesospheric Heights in the Northern Hemisphere during 1961-2013

    NASA Astrophysics Data System (ADS)

    Berger, Uwe; Baumgarten, Gerd; Luebken, Franz Josef

    2016-04-01

    We have performed trend studies in the mesosphere in the period 1961-2013 with Leibniz-Institute Middle Atmosphere (LIMA) model driven by European Centre for Medium-Range Weather Forecasts reanalysis (ERA-interim) below approximately 45 km. LIMA adapts temporal variations of CO2 and O3 according to observations, and observed daily Lyman alpha fluxes. The simulation of the thermal state at the summer upper mesosphere allows to investigate the impact on the morphology of ice particle related phenomena such as polar mesosphere clouds (PMC). The PMC characteristics deduced from LIMA are validated with various data sets from satellite (NOAA-SBUV, AIM-SOFIE) observations. Generally good agreement is found between the modeled long-term PMC variations and that derived from SBUV observations. We investigate the role of trends in mesospheric water vapor and temperature that mainly force PMC trends. We show that water vapor and temperatures in the stratosphere/meso- sphere/lower thermosphere vary none-uniformly with time. Especially, we analyze the contribution of varying concentrations of CO2 and O3 to the temperature trend in the mesosphere. It is important to distinguish between trends on pressure altitudes and geometrical altitudes, where the latter includes the effect of shrinking due to cooling at lower heights. As a highlight, we will present first results in analyzing the very first appearance of NLC in 1885 observed after the volcanic eruption of Krakatao in August 1883 that injected a tremendous mass of water vapor into the stratosphere.

  2. Characteristics of mesosphere echoes over Antarctica obtained using PANSY and MF radars

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Masaki; Nakamura, Takuji; Sato, Toru; Nishimura, Koji; Sato, Kaoru; Tomikawa, Yoshihiro; Kohma, Masashi

    2016-07-01

    In the polar region characteristic radar echoes are observed from the mesosphere by using a VHF system. The nature of the echoes is distinctively different between summer and winter and those echoes are called Polar Mesosphere Summer Echoes (PMSEs) and Polar Mesosphere Winter Echoes (PMWEs), respectively. Since the PMSEs are usually very strong and can be easily measured with a small radar system, their nature is relatively well understood. On the other hand PMWEs are much weaker and they are still only poorly understood. The PANSY radar (47MHz) at Syowa station (69S) is the only large aperture atmospheric radar in the Antarctic, and can continuously survey the dynamics of the middle atmosphere with high time and height resolutions [Sato et al., 2014]. Nishiyama et al [2014] reported the first study of PMWEs using PANSY radar and showed a seasonal and local time dependence of these echoes. An MF radar system (2.4MHz) is co-located at Syowa, and has been operating for mesosphere and lower thermosphere observations. Although the MF radar has only a much poorer height resolution and is incapable of vertical wind measurement, it can almost continuously measure mesosphere day and night. In this study the nature of the mesosphere echoes, mainly PMWEs, are being studied using the two radars based on the observation made in 2015. These radars are operated using largely different radio frequencies and can provide complementary information with each other such as wind velocities and also echo scattering mechanisms. Horizontal wind velocities have been compared between the two radars with a great care mostly in the MF radar winds in order to avoid possible biases inherent in the correlation analysis technique employed for the MF radar wind measurement. A careful analysis has shown that the horizontal wind velocities agree well between the two systems with a high correlation coefficient around 0.8 throughout the height region of 65-85km. Aspect sensitivities estimated using

  3. Winter Mesospheric Thermal Structure over Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Qiao, Shuai; Pan, Weilin; Lü, Daren

    2016-06-01

    A mobile Rayleigh temperature lidar was deployed in Golmud (36.25°N 94.54°E), Qinghai in China for making measurements of mesosphere temperature from 55 up to 90 km. The mesospheric thermal structure was obtained during the winter seasons of Year 2013 and Year 2014. At the altitude of 57~79 km, lidar temperatures were much colder than the MSIS-00 model predictions. However, in the lower mesosphere region, lidar measurements were in reasonable agreement compared with the TIMED-SABER satellite data.

  4. Solar Mesosphere Explorer observations of stratospheric and mesospheric water vapor

    NASA Technical Reports Server (NTRS)

    Jakosky, Bruce M.; Thomas, Gary E.; Rusch, David W.; Barth, Charles A.; Lawrence, George M.; Olivero, John J.; Clancy, R. Todd; Sanders, Ryan W.; Knapp, Barry G.

    1988-01-01

    It is noted that while the SME (Solar Mesosphere Explorer) data is consistent with the earlier LIMS (Limb Infrared Monitor of the Stratosphere) results, its interpretation is complicated by aerosol contamination, particularly at altitudes below 35 km. This contamination arose from several volcanic eruptions, including that of El Chichon. Analyses are reported of a subset of data from the SME satellite, concentrating primarily on the period January through March 1982 so as to avoid contamination from the El Chichon volcanic aerosol. The SME observations of water vapor between 20 and 60 km were inverted for the first three months of 1982 as well as for selected additional periods. Reasonable results are obtained at locations where no contamination by aerosol is suspected.

  5. High affinity sorption domains in soil are blocked by polar soil organic matter components.

    PubMed

    Mitchell, Perry J; Simpson, Myrna J

    2013-01-01

    Reported correlations between organic contaminant sorption affinity and soil organic matter (OM) structure vary widely, suggesting the importance of OM physical conformation and accessibility. Batch equilibration experiments were used to examine the sorption affinity of bisphenol A, atrazine, and diuron to five soils of varying OM composition. (13)C cross-polarization magic angle spinning NMR spectroscopy was used to characterize the organic carbon chemistry of the soil samples. High sorption by a soil low in O-alkyl components suggested that these structures may block high affinity sorption sites in soil OM. As such, soil samples were subjected to acid hydrolysis, and NMR results showed a decrease in the O-alkyl carbon signal intensity for all soils. Subsequent sorption experiments revealed that organic carbon-normalized distribution coefficient (K(OC)) values increased for all three contaminants. Before hydrolysis, K(OC) values correlated positively with soil aromatic carbon content and negatively with polar soil O-alkyl carbon content. While these correlations were weaker after hydrolysis, the correlation between K(OC) values and soil alkyl carbon content improved. This study suggests that hydrolyzable O-alkyl soil OM components may block high affinity sorption sites and further highlights the importance of OM physical conformation and accessibility with respect to sorption processes. PMID:23206246

  6. Impacts of Polar Changes on the UV-induced Mineralization of Terrigenous Dissolved Organic Matter.

    PubMed

    Sulzberger, Barbara; Arey, J Samuel

    2016-07-01

    Local climates in the Northern and Southern Hemisphere are influenced by Arctic Amplification and by interactions of the Antarctic ozone hole with climate change, respectively. Polar changes may affect hydroclimatic conditions in temperate regions, for example, by increasing the length and intensity of precipitation events at Northern Hemisphere midlatitudes. Additionally, global warming has led to the thawing of ancient permafrost soils, particularly in Arctic regions, due to Arctic Amplification. Both heavy precipitation events and thawing of permafrost are increasing the net transfer of terrestrially derived dissolved organic matter (DOM) from land to surface waters. In aquatic ecosystems, UV-induced oxidation of terrigenous DOM (tDOM) produces atmospheric CO2 and this process is one of several mechanisms by which natural organic matter in aquatic and soil environments may play an important role in climate feedbacks. The Arctic is particularly affected by these processes: for example, melting of Arctic sea ice allows solar UV radiation to penetrate into the ice-free Arctic Ocean and to cause photochemical reactions that result in bleaching and mineralization of tDOM. Open questions, in addition to those shown in the Graphical Abstract, remain regarding the resulting contributions of tDOM photomineralization to CO2 production and global warming. PMID:27110903

  7. Mesosphere-Stratosphere Coupling: Implications for Climate Variability and Trends

    NASA Technical Reports Server (NTRS)

    Baldwin, Mark P.

    2004-01-01

    A key aspect of this project is the establishment of a causal link from circulation anomalies in the lower mesosphere and stratopause region downward through the stratosphere to the troposphere. The observational link for stratospheric sudden warmings and surface climate is fairly clear. However, our understanding of the dynamics is incomplete. We have been making significant progress in the area of dynamical mechanisms by which circulation anomalies in the stratosphere affect the troposphere. We are trying to understand the details and sequence of events that occur when a middle atmosphere (wind) anomaly propagates downward to near the tropopause. The wind anomaly could be caused by a warming or solar variations in the low-latitude stratopause region, or could have other causes. The observations show a picture that is consistent with a circulation anomaly that descends to the tropopause region, and can be detected as low as the mid-troposphere. Processes near the stratopause in the tropics appear to be important precursors to the wintertime development of the northern polar vortex. This may affect significantly our understanding of the process by which low-latitude wind anomalies in the low mesosphere and upper stratosphere evolve through the winter and affect the polar vortex.

  8. The influence of the residual circulation on hemispheric differences in the mesosphere

    NASA Astrophysics Data System (ADS)

    karlsson, B.

    2012-12-01

    The residual circulation in the middle atmosphere has a large impact on the temperature field in the mesosphere. Due to its upward motion at high latitudes in the summer hemisphere, this region is driven towards extremely low temperatures through adiabatic cooling. At the same time, the temperature is well above radiative equilibrium in the winter lower mesosphere, due to down welling and adiabatic heating. This gravity wave driven circulation also supplies the summer mesosphere with water vapor from the lower atmosphere and transports particles from one part of the globe to another. Intriguingly, it is the dynamics in the winter high latitude troposphere and stratosphere that determine the strength of this circulation, even in the summer polar mesopause region. Noctilucent clouds (NLC), which can be thought of as a visible part of this pole-to-pole circulation, can teach us more about how the middle atmosphere behaves. The onset of these mesospheric clouds is affected by the persistence of the winter polar vortex in the same hemisphere as the clouds (intra-hemispheric coupling), whereas the mid-seasonal variability is driven by the stratospheric winter conditions in the opposite hemisphere (inter-hemispheric coupling). In this presentation, the consequences of these coupling processes will be discussed in terms of hemispheric differences observed in the NLC.

  9. Simulation study for measurement of horizontal wind profiles in the polar stratosphere and mesosphere using ground-based observations of ozone and carbon monoxide lines in the 230-250 GHz region

    NASA Astrophysics Data System (ADS)

    Newnham, David A.; Ford, George P.; Moffat-Griffin, Tracy; Pumphrey, Hugh C.

    2016-07-01

    Meteorological and atmospheric models are being extended up to 80 km altitude but there are very few observing techniques that can measure stratospheric-mesospheric winds at altitudes between 20 and 80 km to verify model datasets. Here we demonstrate the feasibility of horizontal wind profile measurements using ground-based passive millimetre-wave spectroradiometric observations of ozone lines centred at 231.28, 249.79, and 249.96 GHz. Vertical profiles of horizontal winds are retrieved from forward and inverse modelling simulations of the line-of-sight Doppler-shifted atmospheric emission lines above Halley station (75°37' S, 26°14' W), Antarctica. For a radiometer with a system temperature of 1400 K and 30 kHz spectral resolution observing the ozone 231.28 GHz line we estimate that 12 h zonal and meridional wind profiles could be determined over the altitude range 25-74 km in winter, and 28-66 km in summer. Height-dependent measurement uncertainties are in the range 3-8 m s-1 and vertical resolution ˜ 8-16 km. Under optimum observing conditions at Halley a temporal resolution of 1.5 h for measuring either zonal or meridional winds is possible, reducing to 0.5 h for a radiometer with a 700 K system temperature. Combining observations of the 231.28 GHz ozone line and the 230.54 GHz carbon monoxide line gives additional altitude coverage at 85 ± 12 km. The effects of clear-sky seasonal mean winter/summer conditions, zenith angle of the received atmospheric emission, and spectrometer frequency resolution on the altitude coverage, measurement uncertainty, and height and time resolution of the retrieved wind profiles have been determined.

  10. To be or not to be oblate: the shape of the dark matter halo in polar ring galaxies

    NASA Astrophysics Data System (ADS)

    Khoperskov, S. A.; Moiseev, A. V.; Khoperskov, A. V.; Saburova, A. S.

    2014-07-01

    With the aim of determining the spatial distribution of the dark matter halo, we investigate two polar ring galaxies, NGC 4262 and SPRC-7. For both galaxies, the stellar kinematics data for the central galaxy were obtained from optical spectroscopy at the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. Information about polar gaseous components was taken from optical three-dimensional spectroscopic observations of ionized gas (for SPRC-7) and from H I radio observations (for NGC 4262). SPRC-7 is a system with a relative angle δ = 73° towards the central galaxy and quite a massive stellar-gaseous polar component. Meanwhile, NGC 4262 is a classic polar case with δ = 88°, where the polar ring mainly consists of neutral gas with a negligible stellar contribution to the mass. Thus, we are dealing with two different systems, and the results are also diverse. The observed properties of both galaxies were compared with the results of self-consistent simulations of velocity fields of the polar component along with the rotation curve of the central lenticular galaxy. For SPRC-7, we have found a slightly flattened halo towards the polar plane with the axial ratio c/a ≃ 1.7 ± 0.2 for the isothermal halo model and c/a ≃ 1.5 ± 0.2 for the NFW model. NGC 4262 is more unusual, because the shape of the dark matter distribution varies strongly with radius. That is, the dark matter halo is flattened in the vicinity of the galactic disc (c/a ≈ 0.4 ± 0.1), but it is prolate far beyond the central galaxy (c/a ≈ 1.7 for the isothermal halo model and c/a ≈ 2.3 for the NFW model).

  11. Exposure to Atmospheric Particulate Matter Enhances Th17 Polarization through the Aryl Hydrocarbon Receptor

    PubMed Central

    van Voorhis, Michael; Knopp, Samantha; Julliard, Walker; Fechner, John H.; Zhang, Xiaoji; Schauer, James J.; Mezrich, Joshua D.

    2013-01-01

    Lung diseases, including asthma, COPD, and other autoimmune lung pathologies are aggravated by exposure to particulate matter (PM) found in air pollution. IL-17 has been shown to exacerbate airway disease in animal models. As PM is known to contain aryl hydrocarbon receptor (AHR) ligands and the AHR has recently been shown to play a role in differentiation of Th17 T cells, the aim of this study was to determine whether exposure to PM could impact Th17 polarization in an AHR-dependent manner. This study used both cell culture techniques and in vivo exposure in mice to examine the response of T cells to PM. Initially experiments were conducted with urban dust particles from a standard reference material, and ultimately repeated with freshly collected samples of diesel exhaust and cigarette smoke. The readout for the assays was increased T cell differentiation as indicated by increased generation of IL-17A in culture, and increased populations of IL-17 producing cells by intracellular flow cytometry. The data illustrate that Th17 polarization was significantly enhanced by addition of urban dust in a dose dependent fashion in cultures of wild-type but not AHR-/- mice. The data further suggest that polycyclic aromatic hydrocarbons played a primary role in this enhancement. There was both an increase of Th17 cell differentiation, and also an increase in the amount of IL-17 secreted by the cells. In summary, this paper identifies a novel mechanism whereby PM can directly act on the AHR in T cells, leading to enhanced Th17 differentiation. Further understanding of the molecular mechanisms responsible for pathologic Th17 differentiation and autoimmunity seen after exposure to pollution will allow direct targeting of proteins involved in AHR activation and function for treatment of PM exposures. PMID:24349309

  12. Temperature trends in the midlatitude summer mesosphere

    NASA Astrophysics Data System (ADS)

    Lübken, F.-J.; Berger, U.; Baumgarten, G.

    2013-12-01

    We have performed trend studies in the mesosphere in the period 1961-2009 with Leibniz-Institute Middle Atmosphere (LIMA) model driven by European Centre for Medium-Range Weather Forecasts reanalysis below approximately 40 km and adapts temporal variations of CO2 and O3 according to observations. Temperatures in the mesosphere/lower thermosphere vary nonuniformly with time, mainly due to the influence of O3. Here we analyze the contribution of varying concentrations of CO2 and O3 to the temperature trend in the mesosphere. It is important to distinguish between trends on pressure altitudes, zp, and geometrical altitudes, zgeo, where the latter includes the effect of shrinking due to cooling at lower heights. For the period 1961-2009, temperature trends on geometrical and pressure altitudes can differ by as much as -0.9 K/dec in the mesosphere. Temperature trends reach approximately -1.3±0.11 K/dec at zp˜60 km and -1.8±0.18 K/dec at zgeo˜70 km, respectively. CO2 is the main driver of these trends in the mesosphere, whereas O3 contributes approximately one third, both on geometrical and pressure heights. Depending on the time period chosen, linear temperature trends can vary substantially. Altitudes of pressure levels in the mesosphere decrease by up to several hundred meters. We have performed long-term runs with LIMA applying twentieth century reanalysis dating back to 1871. Again, trends are nonuniform with time. Since the late nineteenth century, temperatures in the mesosphere have dropped by approximately 5-7 K on pressure altitudes and up to 10-12 K on geometrical altitudes.

  13. Observed impact of energetic particles on the stratosphere and mesosphere and its role in global change

    NASA Astrophysics Data System (ADS)

    Jackman, C. H.

    2011-12-01

    Energetic precipitating particles (EPPs) can cause significant constituent changes in the polar stratosphere and mesosphere (middle atmosphere) during certain periods. Both protons and electrons can influence the polar middle atmosphere through ionization and dissociation processes. EPPs can enhance HOx (H, OH, HO2) through the formation of positive ions followed by complex ion chemistry and NOx (N, NO, NO2) through the dissociation of molecular nitrogen. The HOx increases can lead to ozone destruction in the mesosphere and upper stratosphere via several catalytic loss cycles. Such middle atmospheric HOx-caused ozone loss is rather short-lived due to the relatively short lifetime (hours) of the HOx constituents. HOx enhancements due to SPEs were confirmed by observations in the past solar cycle and HOx-caused ozone depletion has been observed during several solar proton events in the past 50 years. The NOx family has a longer lifetime than the HOx family and can also lead to catalytic ozone destruction. EPP-caused enhancements of the NOx family can affect ozone promptly, if produced in the stratosphere, or subsequently, if produced in the lower thermosphere or mesosphere and transported to the stratosphere. NOx enhancements due to auroral electrons, medium and high energy electrons, relativistic electron precipitation events, and solar proton events have been measured and/or modeled for decades. Model predictions and measurements show that certain years have significant winter-time meteorological events, which result in the transport of EPP-caused NOx enhancements in the upper mesosphere and lower thermosphere to lower altitudes. A recent study has shown statistically significant changes in polar surface air temperatures correlated with electron precipitation, although the authors suggest that the Northern Annular Mode introduces significant uncertainty into the results (Seppälä et al., J. Geophys. Res., 114, A10312, doi:10.1029/2008JA014029, 2009). Several solar

  14. Active Dust Experiment in the Mesosphere

    SciTech Connect

    Norberg, Carol; Pellinen-Wannberg, Asta

    2008-09-07

    The mesosphere stretches from an altitude of about 50 to 90 km above the Earth's surface. Meteors entering the Earth's atmosphere are believed to ablate and hence give rise to a thin layer of dust particles in the upper part of the Earth's mesosphere. It seems that the dust is most dense in a layer that lies between 80 and 90 km. The dust particles are thought to have sizes of a few to tens of nanometers. Efforts have been made to measure these particles using rockets and radar techniques with limited success. We propose to release dust into the mesosphere over northern Sweden at a height of about 90 km and observe the released dust using the EISCAT radar system. The dust will be launched from the Swedish Space Corporation Esrange Space Centre on a single-stage Improved-Orion rocket that will be launched so that its flight path will be in the radar field of view.

  15. Microwave spectra of terrestrial mesospheric CO

    NASA Technical Reports Server (NTRS)

    Clancy, R. T.; Muhleman, D. O.; Berge, G. L.

    1982-01-01

    Mesospheric CO was observed in absorption against the moon in early December 1979 at a wavelength of 1.3 mm and in early December 1980 at 2.6 mm with the 10.4-m millimeter wavelength telescope at the Owens Valley Radio Observatory. No significant change in the column density of CO above about 65 km is found between the 1979 and 1980 observations. Comparison with other published spectra of mesospheric CO suggests a large seasonal variation (about a factor of 2-3) in the column density of CO above 65 km, with a maximum in winter and a minimum in summer. It is concluded that the understanding of CO in the mesosphere can be improved with earth-based microwave measurements, but data with high signal-to-noise ratios must be obtained.

  16. A review of mesospheric dynamics and chemistry

    SciTech Connect

    Viereck, R.A. )

    1991-01-01

    Advances made in understanding the chemistry and dynamics of the atmosphere in the approximate altitude range of 50 to 90 km are addressed. Attention is given to mesospheric structure and seasonal variations, gravity waves and gravity wave saturation, the effects of gravity waves on thermal, momentum and constituent fluxes, and the effect of gravity waves on airglow emissions. A review of research on tides and planetary waves and their effects on the mesosphere are presented as well as discussions on ozone hydroxyl, water vapor, and noctilucent cloud research. 217 refs.

  17. Mesospheric dynamics and chemistry from SME data

    NASA Technical Reports Server (NTRS)

    Strobel, Darrell F.

    1987-01-01

    A fast Curtis matrix calculation of cooling rates due to the 15 micron band of CO2 is modified to parameterize the detailed calculations by Dickinson (1984) of infrared cooling by CO2 in the mesosphere and lower thermosphere. The calculations included separate NLTE treatment of the different 15 micron bands likely to be important for cooling. The goal was to compress the detailed properties of the different bands into a modified Curtis matrix, which represents one composite band with appropriate averaged radiative properties to allow for a simple and quick calculation of cooling rates given a temperature profile. Vertical constituent transport in the mesosphere was also studied.

  18. Three-dimensional numerical simulations of clouds and aerosols in the mesosphere using WACCM/CARMA

    NASA Astrophysics Data System (ADS)

    Bardeen, Charles Gaylord

    Polar mesospheric clouds (PMC) routinely form in the cold summer mesopause region when water vapor condenses to form ice. The exact nucleation mechanism for these ice particles is not known, but one on the leading candidates is the heterogeneous nucleation of ice upon nanometer-sized meteoric dust particles, which are formed by the ablation and recondensation of micrometeorites in the upper mesosphere and lower thermosphere. For this study, WACCM/CARMA, a new three-dimensional chemistry-climate model based upon the Whole-Atmosphere Community Climate Model (WACCM) with sectional microphysics from the Community Aerosol and Radiation Model for Atmospheres (CARMA) was created to investigate the distribution of meteoric dust particles and polar mesospheric clouds. Previous studies with one-dimensional models have determined that the meteoric dust size distribution is sensitive to the background vertical velocity and have speculated on the importance of the mesospheric meridional circulation to the dust spatial distribution. This study presents the first three-dimensional simulations of meteoric dust in the mesosphere and upper stratosphere, showing that the mesospheric meridional circulation causes a strong seasonal pattern in meteoric dust concentration in which the summer pole is depleted and the winter pole is enhanced. This summer pole depletion of dust particles results in fewer dust condensation nuclei (CN) than has traditionally been assumed in numerical simulations of polar mesospheric clouds (PMCs). However, the total number of dust particles present is still sufficient to account for PMCs if smaller particles can nucleate to form ice than is conventionally assumed. During winter, dust is quickly transported down to the stratosphere in the polar vortex where it may participate in the nucleation of sulfate aerosols, the formation of the polar CN layer, and the formation of polar stratospheric clouds (PSCs). These predictions of the seasonal variation and

  19. Circulation of Venus upper mesosphere.

    NASA Astrophysics Data System (ADS)

    Zasova, Ludmila; Gorinov, Dmitry; Shakun, Alexey; Altieri, Francesca; Migliorini, Alessandra; Piccioni, Giuseppe; Drossart, Pierre

    2014-05-01

    Observation of the O2 1.27 μm airglow intensity distribution on the night side of Venus is one of the methods of study of the circulation in upper mesosphere 90-100 km. VIRTIS-M on board Venus Express made these observations in nadir and limb modes in Southern and Northern hemispheres respectively. Global map of the O2 night glow is published (Piccioni et al. 2009). In this work we use for analysis only data, obtained with exposure > 3 s to avoid high noisy data. It was found that intensity of emission decreases to poles and to terminators (similar to Piccioni et al.2009) in both hemispheres, which gives evidence for existence of SS-AS circulation with transport of the air masses through poles and terminators with ascending/descending flows at SS/AS areas. However, asymmetry of distribution of intensity of airglow is observed in both hemispheres. Global map for southern hemisphere (from nadir data) has good statistics at φ > 10-20° S and pretty poor at low latitude. Maximum emission is shifted from midnight by 1 - 2 hours to the evening (22-23h) and deep minimum of emission is found at LT=2-4 h at φ > 20° S. This asymmetry is extended up to equatorial region, however statistic is poor there. No evident indication for existence of the Retrograde Zonal Superrotation (RZS) is found: maximum emission in this case, which is resulting from downwards flow, should be shifted to the morning. The thermal tides, gravity waves are evidently influence on the night airglow distribution. VIRTIS limb observations cover the low northern latitudes and they are more sparse at higher latitudes. Intensity of airglow at φ = 0 - 20° N shows wide maximum, which is shifted by 1- 2 h from midnight to morning terminator. This obviously indicates that observed O2 night glow distribution in low North latitudes is explained by a superposition of SS-AS flow and RZS circulation at 95-100 km. This behavior is similar to the NO intensity distribution, obtained by SPICAV.

  20. Investigation of the field-induced ferromagnetic phase transition in spin-polarized neutron matter: A lowest order constrained variational approach

    SciTech Connect

    Bordbar, G. H.; Rezaei, Z.; Montakhab, Afshin

    2011-04-15

    In this article, the lowest order constrained variational method is used to investigate the magnetic properties of spin-polarized neutron matter in the presence of strong magnetic field at zero temperature employing the AV{sub 18} potential. Our results indicate that a ferromagnetic phase transition is induced by a strong magnetic field with strength greater than 10{sup 18} G, leading to a partial spin polarization of the neutron matter. It is also shown that the equation of state of neutron matter in the presence of a magnetic field is stiffer than in the absence of a magnetic field.

  1. The anomalous solid state decomposition of ammonium dinitramide: a matter of surface polarization.

    PubMed

    Rahm, Martin; Brinck, Tore

    2009-05-28

    Polarized dinitramide anions on the surface of solid ammonium dinitramide (ADN) have a decomposition barrier that is reduced by 16 kcal mol(-1) and explain the anomalous solid state decomposition of ADN. PMID:19436902

  2. Signatures of field induced spin polarization of neutron star matter in seismic vibrations of paramagnetic neutron star

    NASA Astrophysics Data System (ADS)

    Bastrukov, S. I.; Yang, J.; Podgainy, D. V.; Weber, F.

    2003-04-01

    A macroscopic model of the dissipative magneto-elastic dynamics of viscous spin polarized nuclear matter is discussed in the context of seismic activity of a paramagnetic neutron star. The source of the magnetic field of such a star is attributed to Pauli paramagnetism of baryon matter promoted by a seed magnetic field frozen into the star in the process of gravitational collapse of a massive progenitor. Particular attention is given to the effect of shear viscosity of incompressible stellar material on the timing of non-radial torsional magneto-elastic pulsations of the star triggered by starquakes. By accentuating the fact that this kind of vibration is unique to the seismology of a paramagnetic neutron star we show that the high-frequency modes decay faster than the low-frequency modes. The obtained analytic expressions for the period and relaxation time of this mode, in which the magnetic susceptibility and viscosity enter as input parameters, are then quantified by numerical estimates for these parameters taken from early and current works on transport coefficients of dense matter. It is found that the effect of viscosity is crucial for the lifetime of magneto-torsion vibrations but it does not appreciably affect the periods of this seismic mode which fall in the realm of periods of pulsed emission of soft gamma-ray repeaters and anomalous x-ray pulsars - young super-magnetized neutron stars, radiating, according to the magnetar model, at the expense of the magnetic energy release. Finally, we present arguments that the long periodic pulsed emission of these stars in a quiescent regime of radiation can be interpreted as a manifestation of weakly damped seismic magneto-torsion vibrations exhibiting the field induced spin polarization of baryon matter.

  3. SOFIE Observations of Meteoric Smoke and Mesospheric Ice

    NASA Astrophysics Data System (ADS)

    Hervig, M. E.; Bardeen, C.

    2013-12-01

    The Solar Occultation for Ice Experiment (SOFIE) has sounded Earth's atmosphere from the Aeronomy of Ice in the Mesosphere (AIM) satellite since early 2007. SOFIE observes polar mesospheric clouds (PMC), meteoric smoke, temperature, and five gaseous species (H2O, O3, NO, CH4, and CO2). In this work, SOFIE observations are compared to SDWACCM model simulations which incorporate concurrent meteorological information, and include the microphysics of PMCs, meteoric smoke, and ice-smoke interactions. SOFIE smoke observations are used to constrain meteoric influx through model - measurement comparisons. The current results indicate that influx is on the low end of candidate values. These results depend on the estimates of meteoric smoke composition from SOFIE multi-wavelength observations, which currently indicate magnesiowüstite, carbon, magnetite or olivine as candidates. SOFIE smoke extinction observations indicate a pronounced seasonal cycle, and an intriguing systematic decrease during summer over the past six years. The abundance of smoke at a given latitude is due to transport by the circulation, and to the influx of meteoric material. The systematic decrease in smoke is interpreted as a manifestation of changing circulation, since concurrent radar observations do not indicate systematic changes in meteoric influx. Potential explanations for changing circulation are explored, including solar variability and increasing greenhouse gases. There is some evidence that sulfate aerosols may exist at altitudes higher than previously thought (~35 km), and this idea will be examined from modelling and observational perspectives. SOFIE observations indicate that the ice particles comprising PMCs contain a small amount of meteoric smoke (0.02-2% by volume), and that the smoke contained in ice is consistent with a composition of magnesiowüstite or carbon. The combined SOFIE and model results are used to examine ice-smoke interactions.

  4. Sprite streamer initiation from natural mesospheric structures.

    PubMed

    Liu, Ningyu; Dwyer, Joseph R; Stenbaek-Nielsen, Hans C; McHarg, Matthew G

    2015-01-01

    Sprites are large, luminous electrical discharges in the upper atmosphere caused by intense cloud-to-ground lightning flashes, manifesting an impulsive coupling mechanism between lower and upper atmospheric regions. Their dynamics are governed by filamentary streamer discharges whose propagation properties have been well studied by past work. However, how they are initiated is still under active debate. It has recently been concluded that ionospheric/mesospheric inhomogeneities are required for their initiation, but it is an open question as to what the sources of those inhomogeneities are. Here we present numerical simulation results to demonstrate that naturally-existing, small-scale mesospheric structures such as those created by gravity waves via instability and breaking are viable sources. The proposed theory is supported by a recent, unique high-speed observation from aircraft flying at 14-km altitude. The theory naturally explains many aspects of observed sprite streamer initiation and has important implications for future observational work. PMID:26118893

  5. A mesospheric source of nitrous oxide

    NASA Technical Reports Server (NTRS)

    Zipf, E. C.; Prasad, S. S.

    1982-01-01

    In the terrestrial atmosphere, nitrous oxide (N2O) has a major role in the chemistry of ozone. Current atmospheric models assume that N2O is produced only by fixation at the earth's surface and that there are no local sources in the stratosphere or mesosphere. It is pointed out here that a significant in situ N2O source does exist above 20 km due to the excitation of the metastable N2(A 3Sigma u +) state by resonance absorption of solar UV photons that penetrate deeply into the atmosphere through the 1,800-2,200 A O2-O3 window. This source significantly affects the NO altitude distribution in the mesosphere and, in the earth's prebiological atmosphere, made N2O an important stratospheric constituent.

  6. Stratospheric and mesospheric observations with ISAMS

    NASA Astrophysics Data System (ADS)

    Taylor, F. W.; Ballard, J.; Dudhia, A.; Goss-Custard, M.; Kerridge, B. J.; Lambert, A.; López-Valverde, M.; Rodgers, C. D.; Remedios, J. J.

    1994-09-01

    The scientific objectives of the Improved Stratospheric and Mesospheric Sounder (ISAMS) experiment involve the measurement of global temperature and composition profiles from an instrument on the Upper Atmosphere Research Satellite (UARS). This paper discusses these objectives in the light of the data acquired during the first ten months of the mission. Interesting interim results include detailed observations of a stratospheric sudden warming and a nitrogen dioxide (NO2) ``Noxon cliff'', enhanced thermospheric nitric oxide (NO) production during a solar flare, strongly increased concentrations of carbon monoxide (CO) over the winter poles, non-LTE behaviour of mesospheric water vapour (H2O), and unexpected transport properties of volcanic aerosol, and the long-lived tracers methane (CH4) and nitrous oxide (N2O).

  7. Stratospheric ozone affects mesospheric temperature trends

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2012-01-01

    Since 1961, temperatures in the summer mesosphere have undergone a series of reversals. From 1961 to 1979 the atmospheric layer that stretches from roughly 50- to 100-kilometer altitude cooled by 0.5 K per decade. In the subsequent 2 decades the rate of cooling escalated to -3 to -5 K per decade, while the next 10 years saw a mild recovery. Though these temperature flips are seen in the observational record, they have never been reliably re-created in computer models of the middle atmosphere. Unlike the troposphere or stratosphere, for which there are extensive records, observations of mesospheric temperature are limited to point-source detections, making accurate modeling particularly important.

  8. Getting to the root of plant iron uptake and cell-cell transport: Polarity matters!

    PubMed Central

    Dubeaux, Guillaume; Zelazny, Enric; Vert, Grégory

    2015-01-01

    Plasma membrane proteins play pivotal roles in mediating responses to endogenous and environmental cues. Regulation of membrane protein levels and establishment of polarity are fundamental for many cellular processes. In plants, IRON-REGULATED TRANSPORTER 1 (IRT1) is the major root iron transporter but is also responsible for the absorption of other divalent metals such as manganese, zinc and cobalt. We recently uncovered that IRT1 is polarly localized to the outer plasma membrane domain of plant root epidermal cells upon depletion of its secondary metal substrates. The endosome-recruited FYVE1 protein interacts with IRT1 in the endocytic pathway and plays a crucial role in the establishment of IRT1 polarity, likely through its recycling to the cell surface. Our work sheds light on the mechanisms of radial transport of nutrients across the different cell types of plant roots toward the vascular tissues and raises interesting parallel with iron transport in mammals. PMID:26479146

  9. Model ozone photochemistry on the basis of Solar Mesosphere Explorer mesospheric observations

    NASA Technical Reports Server (NTRS)

    Clancy, R. T.; Rusch, D. W.; Thomas, R. J.; Allen, M.; Eckman, R. S.

    1987-01-01

    Morning and afternoon mesospheric ozone profiles (50-90 km) measured by the Solar Mesosphere Explorer (SME) satellite are analyzed with one-dimensional photochemical models. The observed ozone abundances are 40 percent and 100 percent greater than the model ozone abundances at 50 and 80 km, respectively. Diurnal model calculations are compared with SME observations of ozone profiles at about 0400 and 1400 LT for high northern summer latitudes. Analysis of the ratios of these early morning and midafternoon ozone profiles provides the additional constraint that larger odd-oxygen production rates are required if lower odd-hydrogen activity is invoked to increase model O3 abundances. The increase in odd-oxygen production must be solar zenith angle independent in the mesosphere, ruling out significant changes in the Schumann-Runge band O2 opacities from Allen and Frederrick (1982).

  10. The effects of precipitating radiation belt electrons on the mesospheric hydroxyl and ozone.

    NASA Astrophysics Data System (ADS)

    Andersson, Monika; Verronen, Pekka T.; Seppälä, Annika; Clilverd, Mark; Rodger, C. J.; Carson, Bonar; Wang, Shuhui

    Energetic electron precipitation (EEP) from the Earth’s outer radiation belt continuously affects the chemical composition of the mesosphere in the polar regions. With the magnitude of the forcing depending on solar activity and magnetic storms, EEP contributes to catalytic ozone loss in the mesosphere through ionisation and enhanced production of hydroxyl (OH). By analysing OH time series from the Microwave Limb Sounder (MLS/AURA) together with electron count rate observations from Medium-Energy Proton and Electron Detector (MEPED/POES) we provide clear evidence of the connection between precipitating radiation belt electrons and mesospheric OH at geomagnetic latitudes 55-65 N/S. Our analysis indicates that for the time period 2004-2009 EEP has measurable effect in about 30% of cases. We investigate the longitudinal distribution of the OH changes, compare the results with MEPED precipitation maps, and discuss the similarities and differences. Finally, by utilising 11 years of observations from the Global Ozone Monitoring by Occultation of Stars (GOMOS/ENVISAT), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER/TIMED) and MLS instruments, we show that the precipitation-induced increase in OH is typically accompanied by decrease in ozone at altitudes between 60-80 km.

  11. Circulation Changes in the Mesosphere and the Lower Thermosphere Associated with Sudden Stratospheric Warmings

    NASA Astrophysics Data System (ADS)

    Hirooka, Toshihiko; Iwao, Koki

    2016-07-01

    Influences of sudden stratospheric warmings (SSWs) reach the mesosphere and the thermosphere. Recently, significant global cooling during SSWs in the thermosphere have been reported on the basis of numerical simulations. However, observational studies are insufficient for the region, so that detailed 3-dimendional structure and the dynamical mechanism are still unclear. Hence, we investigate circulation changes in the mesosphere and thermosphere along with in the stratosphere during SSWs by using TIMED/SABER satellite data and radar data. The SABER observes the atmospheric temperature field in high altitudes up to the lower thermosphere (~120km). Time series of the SABER data includes tidal components, because the satellite orbit is not sun-synchronous and the local time of observation gradually decreases at a specific latitude. The perfect separation of the time series data into tidal and daily changes is difficult especially when diurnal components are amplified. Therefore, we additionally analyze the radar data at some selected stations. Resultantly, north polar temperatures during SSWs show lower thermosphere warming and mesospheric cooling along with the anti-correlated temperature changes in the wide region except over the north pole. In the presentation, we discuss further detailed features of circulation changes associated with SSWs.

  12. Evolution of stationary wave patterns in mesospheric water vapor due to climate change

    NASA Astrophysics Data System (ADS)

    Demirhan Barı, Deniz; Gabriel, Axel; Sezginer Ünal, Yurdanur

    2016-07-01

    The variability in the observed stationary wave patterns of the mesospheric water vapor (H2O) is investigated using CMIP5 RCP 4.5 and RCP 8.5 projections. The change in the vertical and meridional wave structure at northern mid- and polar latitudes associated to the zonal and meridional eddy heat fluxes is discussed by analyzing the advection of H2O due to residual wind components. The alteration in the characteristics of the stationary wave-1 pattern of the lower mesospheric H2O (up to about 75km) related to change in the projected radiative forcing is observed for the years from 2006 to 2100. Additionally the remarkable effect of the increase in global temperature on the zonal asymmetries in small-scale transient waves and parameterized gravity waves, which largely contribute to the observed stationary wave patterns of H2O in the upper mesosphere, is analyzed. For validation purposes, the derived stratospheric patterns are verified against the eddy heat fluxes and residual advection terms derived from Aura/MLS satellite data between 2004-2010 and the reference period of the CMIP5 MPI dataset (1976-2005) providing confidence in the applied method.

  13. Stratospheric and solar cycle effects on long-term variability of mesospheric ice clouds

    NASA Astrophysics Data System (ADS)

    Lübken, F.-J.; Berger, U.; Baumgarten, G.

    2009-01-01

    Model results of mesospheric ice layers and background conditions at 69°N from 1961 to 2008 are analyzed. The model nudges to European Centre for Medium-Range Weather Forecasts data below ˜45 km. Greenhouse gas concentrations in the mesosphere are kept constant. At polar mesospheric cloud (PMC) altitudes (83 km) temperatures decrease until the mid 1990s by -0.08 K/yr resulting in trends of PMC brightness, occurrence rates, and, to a lesser extent, in PMC altitudes (-0.0166 km/yr). Ice layer trends are consistent with observations by ground-based and satellite instruments. Water vapor increases at PMC heights and decreases above due to increased freeze-drying caused by the temperature trend. Temperature trends in the mesosphere mainly come from shrinking of the stratosphere and from dynamical effects. A solar cycle modulation of H2O is observed in the model consistent with satellite observations. The effect on ice layers is reduced because of redistribution of H2O by freeze-drying. The accidental coincidence of low temperatures and solar cycle minimum in the mid 1990s leads to an overestimation of solar effects on ice layers. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this gives negligible temperature trends at PMC altitudes (˜0.01-0.02 K/yr). Strong correlations between PMC parameters and background conditions deduced from the model confirm the standard scenario of PMC formation. The PMC sensitivity on temperatures, water vapor, and Ly-α is investigated. PMC heights show little variation with background parameters whereas brightness and occurrence rates show large variations. None of the background parameters can be ignored regarding its influence on ice layers.

  14. Stratospheric and solar cycle effects on long-term variability of mesospheric ice clouds

    NASA Astrophysics Data System (ADS)

    Lübken, F.-J.; Berger, U.; Baumgarten, G.

    2009-11-01

    Model results of mesospheric ice layers and background conditions at 69°N from 1961 to 2008 are analyzed. The model nudges to European Centre for Medium-Range Weather Forecasts data below ˜45 km. Greenhouse gas concentrations in the mesosphere are kept constant. At polar mesospheric cloud (PMC) altitudes (83 km) temperatures decrease until the mid 1990s by -0.08 K/yr resulting in trends of PMC brightness, occurrence rates, and, to a lesser extent, in PMC altitudes (-0.0166 km/yr). Ice layer trends are consistent with observations by ground-based and satellite instruments. Water vapor increases at PMC heights and decreases above due to increased freeze-drying caused by the temperature trend. Temperature trends in the mesosphere mainly come from shrinking of the stratosphere and from dynamical effects. A solar cycle modulation of H2O is observed in the model consistent with satellite observations. The effect on ice layers is reduced because of redistribution of H2O by freeze-drying. The accidental coincidence of low temperatures and solar cycle minimum in the mid 1990s leads to an overestimation of solar effects on ice layers. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this gives negligible temperature trends at PMC altitudes (˜0.01-0.02 K/yr). Strong correlations between PMC parameters and background conditions deduced from the model confirm the standard scenario of PMC formation. The PMC sensitivity on temperatures, water vapor, and Ly-α is investigated. PMC heights show little variation with background parameters whereas brightness and occurrence rates show large variations. None of the background parameters can be ignored regarding its influence on ice layers.

  15. Mesospheric CO2 Clouds on Mars: Detection, Properties and Origin

    NASA Astrophysics Data System (ADS)

    Määttänen, A.; Gondet, B.; Montmessin, F.; Hoffmann, H.; González-Galindo, F.; Spiga, A.; Listowski, C.; Bibring, J.-P.

    2014-07-01

    This abstract presents a review of the mesospheric cloud observations performed with OMEGA/MEx, accompanied by HRSC/MEx, and the modeling efforts that permit us today to draw a clearer picture of the formation of the exotic mesospheric CO2 clouds.

  16. An analysis of Solar Mesospheric Explorer temperatures for the upper stratosphere and mesosphere

    NASA Technical Reports Server (NTRS)

    Clancy, R. Todd; Rusch, David W.

    1993-01-01

    We proposed to analyze Solar Mesosphere Explorer (SME) limb profiles of Rayleigh scattered solar flux at wavelengths of 304, 313, and 443 nm to retrieve atmospheric temperature profiles over the 40-65 km altitude region. These temperatures can be combined with the previous analysis of SME 296 nm limb radiances to construct a monthly average climatology of atmospheric temperatures over the 40-90 km, upper stratosphere-mesosphere region, with approximately 4 km vertical resolution. We proposed to investigate the detailed nature of the global temperature structure of this poorly measured region, based on these 1982-1986 SME temperatures. The average vertical structure of temperatures between the stratopause and mesopause has never been determined globally with vertical resolution sufficient to retrieve even scale-height structures. Hence, the SME temperatures provided a unique opportunity to study the detailed thermal structure of the mesosphere, in advance of Upper Atmosphere Research Satellite (UARS) measurements and the Thermosphere Ionosphere Mesosphere Energy and Dynamics (TIMED) mission.

  17. Polar Mesosphere Winter Echoes: Turbulence Versus Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Belova, E.; Kirkwood, S.; Dalin, P. A.

    2013-12-01

    PMWE are strong echoes from 50-80 km altitudes seen by VHF radars in the equinox and winter seasons. The PMWE observational facts are controversial and the echo origin is still under debate. Two main hypotheses were proposed: one explains PMWE by scattering on turbulent structures and another one suggests these structures to be created by sound waves propagated from below. Strong PMWE are relatively rare phenomena, in most cases the radars observe them during extra ionisation in the lower ionosphere. The current solar maximum provides favourable conditions for PMWE observations and in winter 2012-2013 we collected PMWE data using a 50-MHz radar ESRAD located in the Northern Sweden. We will discuss how main characteristics of the echoes support turbulent or non-turbulent origin of PMWE.

  18. Rocket measurements of mesospheric ionization irregularities

    NASA Technical Reports Server (NTRS)

    Stoltzfus, R. B.; Bowhill, S. A.

    1985-01-01

    The Langmuir probe technique for measurement of electron concentration in the mesosphere is capable of excellent altitude resolution, of order 1 m. Measurements from nine daytime rocket flights carrying an electron density fine structure experiment frequently show small scale ionization structures in the altitude region 70 to 90 km. The irregularities are believed to be the result of turbulent advection of ions and electrons. The fine structure experiment flown by the University of Illinois is described and methods of analyzing the collected data is presented. Theories of homogeneous, isotropic turbulence are reviewed. Power spectra of the measured irregularities are calculated and compared to spectra predicted by turbulence theories.

  19. MACE - the "Mesosphere and Climate Experiment"

    NASA Astrophysics Data System (ADS)

    Orphal, Johannes

    2012-07-01

    MACE has been proposed to ESA for operation on the ISS. MACE will address important questions, especially how much climate change is influenced by external factors like the sun or cosmic rays, using new observations of the mesosphere, with unprecedented horizontal sampling and accuracy. MACE has been developed based on the heritage of previous successful satellite missions, and will benefit strongly from the ISS orbit, and from recent space-qualified 2D detector technologies. MACE will be a very significant step forward in our understanding of the anthropogenic and natural contributions to Climate Change.

  20. Microstructural Analysis of Human White Matter Architecture Using Polarized Light Imaging: Views from Neuroanatomy

    PubMed Central

    Axer, Hubertus; Beck, Sindy; Axer, Markus; Schuchardt, Friederike; Heepe, Jörn; Flücken, Anja; Axer, Martina; Prescher, Andreas; Witte, Otto W.

    2011-01-01

    To date, there are several methods for mapping connectivity, ranging from the macroscopic to molecular scales. However, it is difficult to integrate this multiply-scaled data into one concept. Polarized light imaging (PLI) is a method to quantify fiber orientation in gross histological brain sections based on the birefringent properties of the myelin sheaths. The method is capable of imaging fiber orientation of larger-scale architectural patterns with higher detail than diffusion MRI of the human brain. PLI analyses light transmission through a gross histological section of a human brain under rotation of a polarization filter combination. Estimates of the angle of fiber direction and the angle of fiber inclination are automatically calculated at every point of the imaged section. Multiple sections can be assembled into a 3D volume. We describe the principles of PLI and present several studies of fiber anatomy as a synopsis of PLI: six brainstems were serially sectioned, imaged with PLI, and 3D reconstructed. Pyramidal tract and lemniscus medialis were segmented in the PLI datasets. PLI data from the internal capsule was related to results from confocal laser scanning microscopy, which is a method of smaller scale fiber anatomy. PLI fiber architecture of the extreme capsule was compared to macroscopical dissection, which represents a method of larger-scale anatomy. The microstructure of the anterior human cingulum bundle was analyzed in serial sections of six human brains. PLI can generate highly resolved 3D datasets of fiber orientation of the human brain and has high comparability to diffusion MR. To get additional information regarding axon structure and density, PLI can also be combined with classical histological stains. It brings the directional aspects of diffusion MRI into the range of histology and may represent a promising tool to close the gap between larger-scale diffusion orientation and microstructural histological analysis of connectivity. PMID

  1. Proposed geomagnetic control of semiannual waves in the mesospheric zonal wind

    NASA Technical Reports Server (NTRS)

    Belmont, A. D.; Nastrom, G. D.; Mayr, H. G.

    1974-01-01

    The polar semiannual oscillation in zonal wind can explain midwinter weakening of the polar vortex and the relatively short stratospheric and mesospheric summar easterlies. The phase of the wind oscillation is equinoctial, as is the phase of the semiannual component in magnetic storm activity. For a given altitude, the contours of amplitude of the semiannual wind oscillation have less variability in geomagnetic than in geographic coordinates. It is suggested that polar wind oscillations are caused by the semiannual maxima in magnetic storm activity which lead to electron dissociation of O2 into O, in turn increasing ozone more rapidly than the dissociation of N2 destroys ozone, and thereby inducing a semiannual variation in the thermal and wind fields. This implies that geomagnetic processes may cause or affect the development of sudden warmings. As the tropical semiannual wind oscillation is symmetric about the geomagnetic equator, the same processes may also influence the location of the tropical wind wave.

  2. Proposed geomagnetic control of semiannual waves in the mesospheric zonal wind

    NASA Technical Reports Server (NTRS)

    Belmont, A. D.; Nastrom, G. D.; Mayr, H. G.

    1975-01-01

    The polar semiannual oscillation in zonal wind explains midwinter weakening of the polar vortex and the relatively short stratospheric and mesospheric summer easterlies. The phase of the wind oscillation is equinoctial, as is the phase of the semiannual component in magnetic storm activity. For a given altitude, the contours of amplitude of the semiannual wind oscillation have less variability in geomagnetic than in geographic coordinates. It is suggested that the polar wind oscillations are caused by the semiannual maxima in magnetic storm activity, which lead to electron dissociation of O2 into O, in turn increasing ozone more rapidly than the dissociation of N2 destroys ozone, and inducing a semiannual variation in the thermal and wind fields. This implies that geomagnetic processes may cause or affect the development of sudden warmings. As the tropical semiannual wind oscillation is symmetric about the geomagnetic equator, the same processes may also influence the location of the tropical wind wave.

  3. Mesospheric heating due to intense tropospheric convection

    NASA Technical Reports Server (NTRS)

    Taylor, L. L.

    1979-01-01

    A series of rocket measurements made twice daily at Wallops Island, Va., revealed a rapid heating of the mesosphere on the order of 10 K on days when thunderstorms or squall lines were in the area. This heating is explained as the result of frictional dissipation of vertically propagating internal gravity waves generated by intense tropospheric convection. Ray-tracing theory is used to determine the spectrum of gravity wave groups that actually reach mesospheric heights. This knowledge is used in an equation describing the spectral energy density of a penetrative convective element to calculate the fraction of the total energy initially available to excite those waves that do reach the level of heating. This value, converted into a vertical velocity, is used as the lower boundary condition for a multilayer model used to determine the detailed structure of the vertically propagating waves. The amount of frictional dissipation produced by the waves is calculated from the solutions of the frictionless model by use of a vertically varying eddy viscosity coefficient. The heating produced by the dissipation is then calculated from the thermodynamic equation.

  4. Ozone in the upper stratosphere and mesosphere

    SciTech Connect

    Prather, M.J.

    1981-06-20

    A detailed photochemical model of the upper stratosphere and mesosphere is compared with three extensive sets of ozone observations: Atmospheric Explorer-E backscattered ultraviolet experiment (BUV), Nimbus-4 BUV, and rocket flights from Wallops Flight Center (ROCOZ). The Nimbus-4 and rocket observations are most sensitive to ozone between 30 and 50 km, whereas observations from AE-E measure the abundance of ozone up to 70 km. The photochemical model accurately reproduces the observed relationship between BUV intensity and local solar zenith angle, although the absolute calibration on AE-E appears to be in error. The AE-E observations and the model both exhibit a morning-afternoon asymmetry, with more ozone in the morning owing to the build up of HO/sub x/ species in the afternoon. Seasonal changes in atmospheric temperature produce an annual maximum in tropical mesospheric ozone during June-July-August. The amplitude of the observed effect is somewhat larger than calculated by the model. Some problems appear to remain with the presently accepted kinetic rates for HO/sub x/ species in the atmosphere. 71 references, 19 figures, 6 tables.

  5. The near‐global mesospheric potassium layer: Observations and modeling

    PubMed Central

    Dawkins, E. C. M.; Chipperfield, M. P.; Feng, W.

    2015-01-01

    Abstract The meteoric metal layers act as unique tracers of chemistry and dynamics in the upper atmosphere. Existing lidar studies from a few locations show that K exhibits a semiannual seasonality (winter and summer maxima), quite unlike the annual seasonality (winter maximum and summer minimum) seen with Na and Fe. This work uses spaceborne observations made with the Optical Spectrograph and InfraRed Imager System instrument on the Odin satellite to retrieve the near‐global K layer for the first time. The satellite data (2004 to mid‐2013) are used to validate the implementation of a recently proposed potassium chemistry scheme in a whole atmosphere chemistry climate model, which provides a chemical basis for this semiannual seasonal behavior. The satellite and model data show that this semiannual seasonality is near global in extent, with the strongest variation at middle and high latitudes. The column abundance, centroid layer height, and root‐mean‐square width of the K layer are consistent with the limited available lidar record. The K data set is then used to investigate the impact of polar mesospheric clouds on the metal layers at high latitudes during summer. Finally, the occurrence frequency of sporadic K layers and their possible link to sporadic E layers are examined. PMID:27478716

  6. Connecting small-scale turbulence to large-scale dynamics in the mesosphere using the Mesosphere-Lower Thermosphere Turbulence Experiment (MTeX)

    NASA Astrophysics Data System (ADS)

    Triplett, C. C.; Collins, R. L.; Lehmacher, G. A.; Barjatya, A.; Fritts, D. C.; Luebken, F. J.; Thurairajah, B.; Harvey, V. L.

    2015-12-01

    The general circulation of the middle and upper atmosphere is determined by waves that form in the lower atmosphere. Large-scale Rossby waves and small-scale gravity waves propagate upward and release their energy in regions of instability such as critical layers. Rossby wave breaking leads to large scale disturbances in the wind and temperature fields known as a sudden stratospheric warming (SSW). These have a great impact on the seasonal weather and climate of the middle atmosphere. SSW events have a particular relationship with gravity waves in the Arctic middle atmosphere. During these events gravity waves reestablish geostrophic balance in the wind field, i.e. the stratospheric polar jet. This return to geostrophic balance, called geostrophic adjustment, generates gravity waves. We used the data from a recent rocket mission, lidar measurements, satellites, and MERRA to understand the coupling of small scale turbulent motions to large scale wave motions in the atmosphere. The Mesosphere-Lower Thermosphere Turbulence Experiment (MTeX) rocket investigation was composed of two rockets launched from Poker Flat Research Range on 25-26 January 2015. MTeX was launched into a mesospheric inversion layer (MIL) giving us a known meteorology. A neutral density sensor that measured turbulence at 20 cm scales flew on both MTeX payloads. Rayleigh lidar measurements of the stratosphere and mesosphere give us the temperature and density structure at kilometer scales characterized the mean environment as well as gravity waves and the MIL. Satellite measurements allow us to characterize the planetary wave activity. MERRA reanalysis gives us a characterization of the winds and planetary waves and their effect on the generation and propagation of waves from scales of tens to thousands of km. The combination of these three data sources and MERRA reanalysis gives us a view of the waves from the synoptic-scale generation and propagation of waves to the small-scale generation of

  7. An Overview of the Impact of Energetic Particle Precipitation on the Mesosphere and Stratosphere

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.

    2008-01-01

    Energetic precipitating particles (EPPs) can cause significant constituent changes in the polar mesosphere and stratosphere (middle atmosphere) during certain periods. Both protons and electrons can influence the polar middle atmosphere through ionization and dissociation processes. EPPs can enhance HOx (H, OH, HO2) through the formation of positive ions followed by complex ion chemistry and NOx (N, NO, NO2) through the dissociation of molecular nitrogen. The HO, increases can lead to ozone destruction in the mesosphere and upper stratosphere via several catalytic loss cycles. Such middle atmospheric HOx,-caused ozone loss is rather short-lived due to the relatively short lifetime (hours) of the HOx constituents. The HOx,-caused ozone depletion has been observed during several solar proton events (SPEs) in the past 40 years. HOx enhancements due to SPEs were confirmed by observations in the past solar cycle. A number of modeling studies have been undertaken over this time period that show predictions of enhanced HO, accompanied by decreased ozone due to energetic particles. The NO, family has a longer lifetime than the HOx family and can also lead to catalytic ozone destruction. EPP-caused enhancements of the NOx family can affect ozone promptly, if produced in the stratosphere, or subsequently, if produced in the 1ow.er thermosphere or mesosphere and transported to the stratosphere. NOx enhancements due to auroral electrons, medium and high energy electrons, relativistic electron precipitation (REP) events, and SPEs have been measured and/or modeled for decades Only a small number of SPEs (less than 10) in each solar cycle have sufficient flux of high energy protons (greater than 30 MeV) to produce a significant amount of NOx directly in the stratosphere to cause a measurable ozone destruction. Very high energy electrons (greater than 1500 keV) during REP events can also produce NOx directly in the stratosphere, however, the frequency and intensity of these

  8. Characterizing the compositional variation of dissolved organic matter over hydrophobicity and polarity using fluorescence spectra combined with principal component analysis and two-dimensional correlation technique.

    PubMed

    Su, Ben-Sheng; Qu, Zhen; He, Xiao-Song; Song, Ying-Hao; Jia, Li-Min

    2016-05-01

    Dissolved organic matter (DOM) obtained from three leachates with different landfill ages was fractionated, and its compositional variation based on hydrophobicity and polarity was characterized by synchronous fluorescence spectra combined with principal component analysis (PCA) and two-dimensional correlation technique. The results showed that the bulk DOM and its fractions were comprised of tryosine-, tryptophan-, fulvic-, and humic-like substances. Tyrosine-like matter was dominant in the young leachate DOM and its fractions, while tryptophan-, fulvic-, and humic-like substances were the main components in the intermediate and old leachate DOMs and their fractions. Tryosine-, tryptophan-, fulvic-, and humic-like substances varied concurrently with the hydrophobicity and polarity. However, the change ratio of these substances was different for the three leachates. Tyrosine-like matter, humic-like materials, and fulvic-like substances were the most sensitive to the hydrophobicity and polarity in the young, intermediate, and old leachates, respectively. Such an integrated approach jointly enhances the characterization of the hydrophobicity- and polarity-dependent DOM fractions and provides a promising way to elucidate the environmental behaviors of different DOM species. PMID:26841775

  9. The MATS Satellite Mission - Tomographic Perspectives on the Mesosphere

    NASA Astrophysics Data System (ADS)

    Karlsson, B.; Gumbel, J.

    2015-12-01

    Tomography in combination with space-borne limb imaging opens exciting new ways of probing atmospheric structures. MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) is a new Swedish satellite mission that applies these ideas to the mesosphere. MATS science questions focus on mesospheric wave activity and noctilucent clouds. Primary measurement targets are O2 Atmospheric band dayglow and nightglow in the near infrared (759-767 nm) and sunlight scattered from noctilucent clouds in the ultraviolet (270-300 nm). While tomography provides horizontally and vertically resolved data, spectroscopy allows analysis in terms of mesospheric composition, temperature and cloud properties. This poster introduces instrument and analysis ideas, and discusses scientific perspectives and connections to other missions. MATS is being prepared for a launch in 2018.

  10. Seasonal variability of mesospheric water vapor

    NASA Technical Reports Server (NTRS)

    Schwartz, P. R.; Bevilacqua, R. M.; Wilson, W. J.; Ricketts, W. B.; Howard, R. J.

    1985-01-01

    Ground-based spectral line measurements of the 22.2 GHz atmospheric water vapor line in emission were made at the JPL in order to obtain data in a dry climate, and to confirm similar measurements made at the Haystack Observatory. The results obtained from March 1984 to July 1984 and from December 1984 to May 1985, were based on data recorded by a HP9816 microcomputer. The instrument spectrometer was a 64 channel, 62.5 kHz resolution filter bank. Data indicates the existence of a seasonal variation in the abundance of water vapor in the upper mesosphere, with mixing ratios higher in summer than in spring. This is consistent with recent theoretical and observational results. In the area of semiannual oscillation, Haystack data are more consistent than those of JPL, indicating an annual cycle with abundances at maximum in summer and minimum in winter.

  11. Measuring Titan's mesospheric temperatures by infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Penteado, P.; Griffith, C.; Greathouse, T.; Roe, H.; Yelle, R.

    2005-08-01

    Titan's temperature profile is an indicator of the atmospheric energy transport, by radiation, convection and conduction. From the surface up to ˜250 km altitude, the temperature profile was measured by the Voyager 1 radio occultations and infrared spectra. In the troposphere, heating by the surface and low atmosphere by solar radiation absorption and cooling by emission to space are the dominant processes that establish the temperature profile, which decreases from ˜94 K at the surface, to ˜70 K at 200 km. Between 200 and 350 km, the atmosphere radiative absorption and emission balance, and the temperature is approximately constante. At 250-500 km altitudes, observations of stellar occultations reveal oscillations between 170 and 150 K. Atmospheric models predict the existence of a mesosphere, in the region 350-550 km, with the temperature decreasing from ethane and other hydrocarbons' emissions. In this work we analyze emission lines of methane's ν 4 band (8.1 μ m, 1230 cm-1) with high resolution spectra. The line profiles of different intensities allow us to determine the vertical temperature profile for the region 100-600 km, which was not possible with previously available data. We present the first infrared observation that can measure independently the temperatures for the regions 100-200 km, 200-400 km, and 400-600 km. These measurements show the existence of a mesosphere, with a temperature drop of at least 15 K from 380+50-100 km altitude. Paulo Penteado is sponsored by the NASA Planetary Astronomy Program and the Brazilian Government through CAPES.

  12. HDAC inhibition prevents white matter injury by modulating microglia/macrophage polarization through the GSK3β/PTEN/Akt axis.

    PubMed

    Wang, Guohua; Shi, Yejie; Jiang, Xiaoyan; Leak, Rehana K; Hu, Xiaoming; Wu, Yun; Pu, Hongjian; Li, Wei-Wei; Tang, Bo; Wang, Yun; Gao, Yanqin; Zheng, Ping; Bennett, Michael V L; Chen, Jun

    2015-03-01

    Severe traumatic brain injury (TBI) elicits destruction of both gray and white matter, which is exacerbated by secondary proinflammatory responses. Although white matter injury (WMI) is strongly correlated with poor neurological status, the maintenance of white matter integrity is poorly understood, and no current therapies protect both gray and white matter. One candidate approach that may fulfill this role is inhibition of class I/II histone deacetylases (HDACs). Here we demonstrate that the HDAC inhibitor Scriptaid protects white matter up to 35 d after TBI, as shown by reductions in abnormally dephosphorylated neurofilament protein, increases in myelin basic protein, anatomic preservation of myelinated axons, and improved nerve conduction. Furthermore, Scriptaid shifted microglia/macrophage polarization toward the protective M2 phenotype and mitigated inflammation. In primary cocultures of microglia and oligodendrocytes, Scriptaid increased expression of microglial glycogen synthase kinase 3 beta (GSK3β), which phosphorylated and inactivated phosphatase and tensin homologue (PTEN), thereby enhancing phosphatidylinositide 3-kinases (PI3K)/Akt signaling and polarizing microglia toward M2. The increase in GSK3β in microglia and their phenotypic switch to M2 was associated with increased preservation of neighboring oligodendrocytes. These findings are consistent with recent findings that microglial phenotypic switching modulates white matter repair and axonal remyelination and highlight a previously unexplored role for HDAC activity in this process. Furthermore, the functions of GSK3β may be more subtle than previously thought, in that GSK3β can modulate microglial functions via the PTEN/PI3K/Akt signaling pathway and preserve white matter homeostasis. Thus, inhibition of HDACs in microglia is a potential future therapy in TBI and other neurological conditions with white matter destruction. PMID:25691750

  13. Upper mesospheric lunar tides over middle and high latitudes during sudden stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Chau, J. L.; Hoffmann, P.; Pedatella, N. M.; Matthias, V.; Stober, G.

    2015-04-01

    In recent years there have been a series of reported ground- and satellite-based observations of lunar tide signatures in the equatorial and low latitude ionosphere/thermosphere around sudden stratospheric warming (SSW) events. This lower atmosphere/ionosphere coupling has been suggested to be via the E region dynamo. In this work we present the results of analyzing 6 years of hourly upper mesospheric winds from specular meteor radars over a midlatitude (54°N) station and a high latitude (69°N) station. Instead of correlating our results with typical definitions of SSWs, we use the definition of polar vortex weaking (PVW) used by Zhang and Forbes. This definition provides a better representation of the strength in middle atmospheric dynamics that should be responsible for the waves propagating to the E region. We have performed a wave decomposition on hourly wind data in 21 day segments, shifted by 1 day. In addition to the radar wind data, the analysis has been applied to simulations from Whole Atmosphere Community Climate Model Extended version and the thermosphere-ionosphere-mesosphere electrodynamics general circulation model. Our results indicate that the semidiurnal lunar tide (M2) enhances in northern hemispheric winter months, over both middle and high latitudes. The time and magnitude of M2 are highly correlated with the time and associated zonal wind of PVW. At middle/high latitudes, M2 in the upper mesosphere occurs after/before the PVW. At both latitudes, the maximum amplitude of M2 is directly proportional to the strength of PVW westward wind. We have found that M2 amplitudes could be comparable to semidiurnal solar tide amplitudes, particularly around PVW and equinoxes. Besides these general results, we have also found peculiarities in some events, particularly at high latitudes. These peculiarities point to the need of considering the longitudinal features of the polar stratosphere and the upper mesosphere and lower thermosphere regions. For

  14. Impact of data assimilation filtering methods on the mesosphere

    NASA Astrophysics Data System (ADS)

    Sankey, David; Ren, Shuzhan; Polavarapu, Saroja; Rochon, Yves J.; Nezlin, Yulia; Beagley, Stephen

    2007-12-01

    Three-dimensional data assimilation schemes typically produce analyses that are not in balance. This is evidenced by the generation of spurious high-frequency waves during the first 2 d of forecasts which start from analyses. To remove these spurious waves, assimilation systems frequently filter analyses before using them in models. This work examines the behavior of various spurious wave filtering methods in the context of a model with a mesosphere. Since gravity waves comprise a significant portion of the mesospheric energy spectrum, it is necessary to retain naturally occurring high-frequency waves while filtering spurious waves. The results show that filtering the full analysis state can remove many important high-frequency oscillations from the mesosphere. On the other hand, filtering analysis increments preserves much more of the natural variability of the model. The incremental analysis updating scheme and the incremental digital filter, which are equivalent for linear models and identical coefficients, are shown to give very similar results in the context of a realistic nonlinear model. Results also show a nonlocal response to the insertion of analysis increments in the troposphere and stratosphere. The global mean temperature in the vicinity of the model lid and the diurnal tidal amplitudes are sensitive to the choice of filtering schemes because the filters reduce the amount of resolved waves available to propagate upward into mesosphere. This sensitivity of the mesosphere to the filtering of the lower atmosphere is exploited to choose an optimal filter for our system using measurements of the mesosphere.

  15. In-Situ Evidence for a Strong Seasonal Variability of Meteor Smoke at High Northern Latitudes and Implications for Mesospheric ice Nucleation

    NASA Astrophysics Data System (ADS)

    Rapp, M.; Strelnikova, I.; Strelnikov, B.; Baumgarten, G.; Gumbel, J.; Megner, L.; Friedrich, M.; Hoppe, U.; Robertson, S.; Knappmiller, S.; Sternovsky, Z.; Wolff, M.

    2008-12-01

    We report on new in situ measurements of meteor smoke particles (MSPs) and their mesospheric environment from three international field campaigns at the North-Norwegian Andoya Rocket Range. These are the ECOMA campaigns in 2006 and 2008 and the joint ECOMA/MASS campaign in 2007. During these campaigns a total of 6 sounding rockets were successfully launched. The prime instrument of the ECOMA- payload is a detector making use of active photoionization of MSPs and the subsequent detection of corresponding photoelectrons. During the first flight in September 2006, MSPs were detected throughout the mesosphere with concentrations in reasonable agreement with predictions from microphysical models. All later flights with this detector under polar summer conditions, however, do not show any detectable MSP concentration at altitudes below ~75 km, whereas the detector did detect signatures of mesospheric ice particles at about 83 km during all flights. In each of these cases, the mesospheric ice detection is unequivocally confirmed by simultaneous photometer measurements of noctilucent cloud particles on the same rocket payloads. Also, the electrostatic mass spectrometer for nanometer-sized charged aerosol particles MASS which was launched close to the ECOMA-rocket in 2007 did not detect any particle signatures outside the mesospheric ice region. We critically discuss these observations in the context of MSP- and ice particle-microphysics of the mesosphere using simultaneous measurements of the ambient plasma from the same sounding rockets as well as satellite observations of nitric oxide from the Canadian ACE satellite. Taking further into account high resolution temperature measurements from each rocket payload, we tentatively draw conclusions on the feasibility of different potential nucleation pathways such as heterogeneous nucleation on neutral and/or charged MSPs, ionic nucleation, and homogeneous nucleation in the presence of pronounced temperature fluctuations owing

  16. Observed Seasonal to Decadal-Scale Responses in Mesospheric Water Vapor

    NASA Technical Reports Server (NTRS)

    Remsberg, Ellis

    2010-01-01

    The 14-yr (1991-2005) time series of mesospheric water vapor from the Halogen Occultation Experiment (HALOE) are analyzed using multiple linear regression (MLR) techniques for their6 seasonal and longer-period terms from 45S to 45N. The distribution of annual average water vapor shows a decrease from a maximum of 6.5 ppmv at 0.2 hPa to about 3.2 ppmv at 0.01 hPa, in accord with the effects of the photolysis of water vapor due to the Lyman-flux. The distribution of the semi-annual cycle amplitudes is nearly hemispherically symmetric at the low latitudes, while that of the annual cycles show larger amplitudes in the northern hemisphere. The diagnosed 11-yr, or solar cycle, max minus min, water vapor values are of the order of several percent at 0.2 hPa to about 23% at 0.01 hPa. The solar cycle terms have larger values in the northern than in the southern hemisphere, particularly in the middle mesosphere, and the associated linear trend terms are anomalously large in the same region. Those anomalies are due, at least in part, to the fact that the amplitudes of the seasonal cycles were varying at northern mid latitudes during 1991-2005, while the corresponding seasonal terms of the MLR model do not allow for that possibility. Although the 11-yr variation in water vapor is essentially hemispherically-symmetric and anti-phased with the solar cycle flux near 0.01 hPa, the concurrent temperature variations produce slightly colder conditions at the northern high latitudes at solar minimum. It is concluded that this temperature difference is most likely the reason for the greater occurrence of polar mesospheric clouds at the northern versus the southern high latitudes at solar minimum during the HALOE time period.

  17. Meteoric smoke and mesospheric ice particles studied with in-situ techniques: Science highlights from the ECOMA-project

    NASA Astrophysics Data System (ADS)

    Rapp, Markus; Strelnikova, Irina; Strelnikov, Boris; Latteck, Ralph; Baumgarten, Gerd; Friedrich, Martin; Gumbel, Jorg; Hoppe, Ulf-Peter

    A total of six sounding rockets were launched during three field campaigns in the years 2006, 2007, and 2008 from the North-Norwegian Andøya Rocket Range to study the Existence and Charge state Of Meteoric smoke in the middle Atmosphere (ECOMA) and its relation to mesospheric ice particles. A new particle detector was successfully developed which combines the conventional technique of a Faraday-Cup with the active photo ionization of particles and subsequent detection of corresponding photo electrons. In this paper we will give an overview of results from these rocket campaigns. Some noteworthy findings are the experimental verification of meteor smoke existence throughout the entire mesosphere, the first direct in situ measurement of mesospheric ice volume, and new insights into the charging properties of meteoric smoke under the conditions of polar summer. Finally, we will outline future plans for a concluding ECOMA campaign that is scheduled for December 2010 to study the effect of the Geminid meteor shower on the properties of meteor smoke particles in the middle atmosphere.

  18. An experimental investigation of mesospheric ionization

    NASA Technical Reports Server (NTRS)

    Mitchell, J. D.

    1973-01-01

    Mesospheric ionization and its variability are examined. Data were obtained primarily by the parachute-borne blunt probe technique conducted in coordinated rocket experiments at White Sands Missile Range, New Mexico and Wallops Island, Virginia. Electrical conductivity measurements and deduced charge density values from ten rocket launches are presented and discussed. Positive ion conductivity and electron density were found to be relatively invariant with height between 45 and 60 km. Variations in positive conductivity of a factor of two and enhancements in negative conductivity by as much as a factor of four were measured by the blunt probe. A simple lumped parameter ion chemistry model is shown to satisfactorily explain the charge density values for the undisturbed lower D-region. Implications of the data in terms of this model are considered. The principal loss mechanism for positive ions in the 45 to 60 km. region is concluded to be dissociative recombination. Electron densities deduced from the conductivity data are explained by detachment involving a minor neutral constituent which is mixed between 65 and 45 km. and then cuts off sharply below 45 km. A correlation study involving blunt probe measurements shows relatively good agreement between variations in positive conductivity and temperature.

  19. Mesospheric ozone measurements by SAGE II

    NASA Astrophysics Data System (ADS)

    Chu, D. A.; Cunnold, D. M.

    1994-04-01

    SAGE II observations of ozone at sunrise and sunset (solar zenith angle = 90 deg) at approximately the same tropical latitude and on the same day exhibit larger concentrations at sunrise than at sunset between 55 and 65 km. Because of the rapid conversion between atomic oxygen and ozone, the onion-peeling scheme used in SAGE II retrievals, which is based on an assumption of constant ozone, is invalid. A one-dimensional photochemical model is used to simulate the diurnal variation of ozone particularly within the solar zenith angle of 80 deg - 100 deg. This model indicates that the retrieved SAGE II sunrise and sunset ozone values are both overestimated. The Chapman reactions produce an adequate simulation of the ozone sunrise/sunset ratio only below 60 km, while above 60 km this ratio is highly affected by the odd oxygen loss due to odd hydrogen reactions, particularly OH. The SAGE II ozone measurements are in excellent agreement with model results to which an onion peeling procedure is applied. The SAGE II ozone observations provide information on the mesospheric chemistry not only through the ozone profile averages but also from the sunrise/sunset ratio.

  20. Mesospheric ozone measurements by SAGE II

    NASA Technical Reports Server (NTRS)

    Chu, D. A.; Cunnold, D. M.

    1994-01-01

    SAGE II observations of ozone at sunrise and sunset (solar zenith angle = 90 deg) at approximately the same tropical latitude and on the same day exhibit larger concentrations at sunrise than at sunset between 55 and 65 km. Because of the rapid conversion between atomic oxygen and ozone, the onion-peeling scheme used in SAGE II retrievals, which is based on an assumption of constant ozone, is invalid. A one-dimensional photochemical model is used to simulate the diurnal variation of ozone particularly within the solar zenith angle of 80 deg - 100 deg. This model indicates that the retrieved SAGE II sunrise and sunset ozone values are both overestimated. The Chapman reactions produce an adequate simulation of the ozone sunrise/sunset ratio only below 60 km, while above 60 km this ratio is highly affected by the odd oxygen loss due to odd hydrogen reactions, particularly OH. The SAGE II ozone measurements are in excellent agreement with model results to which an onion peeling procedure is applied. The SAGE II ozone observations provide information on the mesospheric chemistry not only through the ozone profile averages but also from the sunrise/sunset ratio.

  1. Large-Scale Waves in the Mesosphere and Lower Thermosphere Observed by SABER.

    NASA Astrophysics Data System (ADS)

    Garcia, Rolando R.; Lieberman, Ruth; Russell, James M., III; Mlynczak, Martin G.

    2005-12-01

    Observations made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board NASA’s Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite have been processed using Salby’s fast Fourier synoptic mapping (FFSM) algorithm. The mapped data provide a first synoptic look at the mean structure and traveling waves of the mesosphere and lower thermosphere (MLT) since the launch of the TIMED satellite in December 2001. The results show the presence of various wave modes in the MLT, which reach largest amplitude above the mesopause and include Kelvin and Rossby gravity waves, eastward-propagating diurnal oscillations (“non-sun-synchronous tides”), and a set of quasi-normal modes associated with the so-called 2-day wave. The latter exhibits marked seasonal variability, attaining large amplitudes during the solstices and all but disappearing at the equinoxes. SABER data also show a strong quasi-stationary Rossby wave signal throughout the middle atmosphere of the winter hemisphere; the signal extends into the Tropics and even into the summer hemisphere in the MLT, suggesting ducting by westerly background zonal winds. At certain times of the year, the 5-day Rossby normal mode and the 4-day wave associated with instability of the polar night jet are also prominent in SABER data.

  2. Remote sensing planetary waves in the midlatitude mesosphere using low frequency transmitter signals

    NASA Astrophysics Data System (ADS)

    Schmitter, E. D.

    2011-07-01

    Very low and low radio frequency (VLF/LF) propagation responds sensitively to the electron density distribution in the lower ionosphere (upper mesosphere). Whereas propagation paths crossing subpolar and polar regions are frequently affected by forcing from above by particle precipitations, mid- and lowlatitude paths let forcing from below be more prominent. Our observations (2009-2011) show, that the low frequency propagation conditions along the midlatitude path from Sicily to Germany (52° N 8° E) using the NSY 45.9 kHz transmitter (37° N 14° E) prove to be a good proxy of mesosphere planetary wave activity along the propagation path. High absorption events with VLF/LF propagation correlate to the well known winter time D-layer anomaly observed with high frequency (HF) radio waves. VLF/LF propagation calculations are presented which show that the radio signal amplitude variations can be modeled by planetary wave modulated collison frequency and electron density profiles. The other way around wave pressure amplitudes can be inferred from the VLF/LF data.

  3. Heterogeneous nucleation and growth of water vapor on meteoric smoke particle analogues at mesospheric conditions

    NASA Astrophysics Data System (ADS)

    Nachbar, Mario; Duft, Denis; Leisner, Thomas

    2016-04-01

    Sub 2 nm meteoric smoke particles (MSP) produced from the ablation and recondensation of meteoric material are believed to be the major kind of nuclei causing the formation of water ice particles in the mesopause of Earth at heights of 80-90 km. These so called noctiLucent clouds (NLC) are frequently detected during polar summer, whereas the microphysical nucleation process and subsequent growth on such small particles are understood only poorly. Parameterizing these processes results in large uncertainties especially due to a lack of experimental data on desorption energies and critical saturation for the activation of nucleation under realistic mesospheric conditions, which states the need of laboratory measurements. We produce charged nanometer sized (2-3 nm) MSP analogues in a microwave plasma particle source and transfer them to a novel linear ion trap which allows us to trap the particles under typical mesospheric temperatures and H2O concentrations. The adsorption of H2O molecules on the particles surface followed by nucleation and growth can be examined by analyzing the mass distribution of the particles with a time-of-flight mass spectrometer as function of the residence time under supersaturated conditions. In this contribution we present such measurements for single positively as well as negatively charged particles which allow us to determine the desorption energy of water vapor on the investigated nanoparticles as well as the critical saturation needed to activate nucleation and subsequent growth.

  4. The response of mesospheric NO to geomagnetic forcing in 2002-2012 as seen by SCIAMACHY

    NASA Astrophysics Data System (ADS)

    Sinnhuber, M.; Friederich, F.; Bender, S.; Burrows, J. P.

    2016-04-01

    Daily NO number density, retrieved from measurements of the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) from 2002 to 2012 for polar summer in the mesosphere, is used to investigate the response of NO to geomagnetic activity, as expressed by the auroral electrojet (AE) index. Applying the superposed epoch analysis, we observe a clear response of NO to strong geomagnetic forcing at geomagnetic latitudes 55-75°N/S and altitudes above 66 km. The 27 day solar rotation cycle is observed, indicating that some of the observed geomagnetic events are related to solar coronal holes. We find a linear relationship between anomalies of AE and NO at geomagnetic latitudes 55-70°N/S and 70-74 km altitude. A clear auroral oval-like structure is observed on days of strong geomagnetic forcing in both hemispheres, with small longitudinal inhomogeneities, which might be related to the South Atlantic Anomaly or the magnetic local time. The NO lifetime and production rate per AE anomaly has been derived from a least squares fit to the observations. Comparisons of results from a simple model using this empirical NO production and a lifetime varying from 1.2 days in summer to 10 days in winter to SCIAMACHY observations show good agreement. In particular, the strength and interannual variability of the wintertime maximum is well captured. This suggests that direct production of NO in the upper mesosphere above 72 km contributes substantially to the so-called energetic particle precipitation indirect effect.

  5. Advanced mesospheric temperature mapper for high-latitude airglow studies.

    PubMed

    Pautet, P-D; Taylor, M J; Pendleton, W R; Zhao, Y; Yuan, T; Esplin, R; McLain, D

    2014-09-10

    Over the past 60 years, ground-based remote sensing measurements of the Earth's mesospheric temperature have been performed using the nighttime hydroxyl (OH) emission, which originates at an altitude of ∼87  km. Several types of instruments have been employed to date: spectrometers, Fabry-Perot or Michelson interferometers, scanning-radiometers, and more recently temperature mappers. Most of them measure the mesospheric temperature in a few sample directions and/or with a limited temporal resolution, restricting their research capabilities to the investigation of larger-scale perturbations such as inertial waves, tides, or planetary waves. The Advanced Mesospheric Temperature Mapper (AMTM) is a novel infrared digital imaging system that measures selected emission lines in the mesospheric OH (3,1) band (at ∼1.5  μm) to create intensity and temperature maps of the mesosphere around 87 km. The data are obtained with an unprecedented spatial (∼0.5  km) and temporal (typically 30″) resolution over a large 120° field of view, allowing detailed measurements of wave propagation and dissipation at the ∼87  km level, even in the presence of strong aurora or under full moon conditions. This paper describes the AMTM characteristics, compares measured temperatures with values obtained by a collocated Na lidar instrument, and presents several examples of temperature maps and nightly keogram representations to illustrate the excellent capabilities of this new instrument. PMID:25321674

  6. Mesospheric Gravity Waves over Indian Regions using Sodium Airglow Measurements

    NASA Astrophysics Data System (ADS)

    Sarkhel, Sumanta; Sekar, R.; Chakrabarty, D.; Narayanan, R.

    In order to identify the dominant modes of mesospheric gravity waves, sodium (Na) airglow mea-surements were carried out in campaign modes during November, 2006 -February, 2009 over Mt. Abu (24.6o N, 72.7o E) and Gadanki (13.5o N, 79.2o E) using a narrow-band and narrow field-of-view Na airglow photometer. The airglow observations yield the temporal variation of altitude-integrated Na airglow intensity. Spectral analyses were carried out using Lomb-Scargle technique that can handle unevenly-spaced Na airglow intensity variation. The power spectra indicate that 15-30 min periods, associated with the mesospheric gravity wave activities, are present in the Na airglow intensity variation over both Mt. Abu and Gadanki. In addition to that, the altitude profiles of upper mesospheric temperature during the observational period were obtained from SABER instrument onboard TIMED satellite over both the sites. Inter-estingly, the average mesospheric temperature profiles over both the sites reveal the mesopause height to be at 98 km. However, on a few occasions, it is observed that the mesopause heights lie a scale height below than 98 km and coincide with the typical Na airglow emission height. The dominant periods derived from the Na airglow variation are significantly different on those occasions. These results will be discussed in the light of mesospheric dynamics and its role in Na airglow intensity variation.

  7. Mesospheric wave number spectra from Poker Flat MST radar measurements compared with gravity-wave model

    NASA Technical Reports Server (NTRS)

    Smith, S. A.; Fritts, D. C.; Vanzandt, T. E.

    1986-01-01

    The results of a comparison of mesospheric wind fluctuation spectra computed from radial wind velocity estimates made by the Poker Flat mesosphere-stratosphere-troposphere (MST) radar are compared with a gravity-wave model developed by VanZandt (1982, 1985). The principal conclusion of this comparison is that gravity waves can account for 80% of the mesospheric power spectral density.

  8. Measurement of mesospheric turbulence in the framework of the metal campaign and development of a sensor for static pressure free measurements of neutral and electron density

    NASA Astrophysics Data System (ADS)

    Foehner, Frank

    1992-11-01

    Six rocket borne ionization gages launched during the METAL campaign were employed to deduce profiles of turbulent energy dissipation rate (epsilon) in the polar mesosphere in Sep. and Oct. 1991. Very small activity of turbulence was found. The influence of epsilon on the energy budget of the polar mesosphere in Autumn is shown to be small in comparison to other heating and cooling effects. After METAL, a new gage for simultaneous measurements of electron and neutral densities was developed in order to improve the overall time constant of the instrument. The operational parameters of this instrument were optimized in the laboratory using vacuum facilities of the plasma chamber. The instrument allows spatial high resolution measurements of temperature and density with a strongly reduced time constant and its stability was proved by vibration tests in view of an implementation on a research rocket.

  9. Occurrence characteristics of Mesosphere Summer Echoes observed by the SuperDARN Hokkaido HF radar

    NASA Astrophysics Data System (ADS)

    Tsuya, T.; Nishitani, N.; Ogawa, T.; Tsutsumi, M.; Yukimatu, A. S.

    2013-12-01

    At high latitudes in summer, neutral temperature of the mesopause around the 85 km altitude goes below about 150 K, heavy charged ice aerosol particles are generated, which reduce electron diffusivity. Neutral air turbulence in combination with the reduced electron diffusivity leads to the creation of structures which backscatter radio waves (Rapp and Lübken, ACP, 2004). As a result, the echoes backscattered near the mesopause are frequently observed in summer in the polar region as Polar Mesosphere Summer Echoes (PMSEs). In recent years mesosphere echoes have been observed not only in the polar region but also at midlatitudes as Mesosphere Summer Echoes (MSEs) (Ogawa et al., JASTP, 2011). In this study, we present a statistical analysis of MSEs observed by the midlatitude SuperDARN Hokkaido HF radar (geographic latitude: +43.53 N deg). We make use of the criteria for identifying MSEs adopted by Ogawa et al. (EPS, in press) who have performed an event study of MSE using the SuperDARN Hokkaido radar. As a result, MSEs are observed more frequently in the daytime (07 to 18 LT) and summer (in particular June and July) than other local times and seasons. This result is similar to the characteristics of PMSEs previously reported by Hosokawa et al. (GRL, 2005) using high latitude SuperDARN radars. MSEs are often contaminated with echoes from the Es layer. In order to identify MSEs exactly and understand the generation mechanisms of MSEs at midlatitudes, it is important to obtain neutral wind information near the mesopause because some MSE structures might be transported from higher latitudes by neutral winds (Singer et al., ASR, 2003), which affect the Doppler velocity of MSEs. If the Doppler velocity of MSEs is consistent with neutral wind velocity, it becomes credible that the echoes are MSEs. In this aspect we can set more appropriate criterion for identifying MSEs by accounting for the altitude distribution of neutral winds. We use the technique employed by Yukimatu

  10. Revised correlation between Odin/OSIRIS PMC properties and coincident TIMED/SABER mesospheric temperatures

    NASA Astrophysics Data System (ADS)

    Feofilov, A.; Petelina, S. V.; Kutepov, A. A.; Pesnell, W. D.; Goldberg, R. A.; Llewellyn, E. J.; Russell, J. M.

    2006-12-01

    The Optical Spectrograph and Infrared Imaging System (OSIRIS) instrument on board the Odin satellite detects Polar Mesospheric Clouds (PMCs) through the enhancement in the limb-scattered solar radiance. The Sounding of the Atmosphere using the Broadband Emission Radiometry (SABER) instrument on board the TIMED satellite is a limb scanning infrared radiometer that measures temperature and vertical profiles and energetic parameters for minor constituents in the mesosphere and lower thermosphere. The combination of OSIRIS and SABER data has been previously used to statistically derive thermal conditions for PMC existence [Petelina et al., 2005]. In this work, we employ the simultaneous common volume measurements of PMCs by OSIRIS and temperature profiles measured by SABER for the Northern Hemisphere summers of 2002--2005 and corrected in the polar region by accounting for the vibrational-vibrational energy exchange among the CO2 isotopes [Kutepov et al., 2006]. For each coincidence identified within ±1 degree latitude, ±2 degrees longitude and ≤1 hour time the frost point temperatures were calculated using the corresponding SABER temperature profile and water vapor densities of 1, 3, and 10 ppmv. We found that the PMC presence and brightness correlated only with the temperature threshold that corresponds to the frost point. The absolute value of the temperature below the frost point, however, didn't play a significant role in the intensity of PMC signal for the majority of selected coincidences. The presence of several bright clouds at temperatures above the frost point is obviously related to the limitation of the limb geometry when some near- or far-field PMCs, actually located at higher (and colder) altitudes are detected at lower altitudes. S.V. Petelina, D.A. Degenstein, E.J. Llewellyn, N.D. Lloyd, C.J. Mertens, M.G. Mlynczak, and J.M. Russell III, "Thermal conditions for PMC existence derived from Odin/OSIRIS and TIMED/SABER data", Geophys. Res. Lett., 32, L

  11. Analysis of charged aerosols in the mesosphere during the MASS/ECOMA rocket campaign

    NASA Astrophysics Data System (ADS)

    Knappmiller, Scott Robert

    In the polar summer mesosphere ice particles grow sufficiently large to scatter sunlight, giving rise to visible cloud displays called Noctilucent Clouds (NLC). In August of 2007, two sounding rockets were launched from the Andoya Rocket Range, Norway carrying the newly developed MASS instrument (Mesospheric Aerosol Sampling Spectrometer) to study NLC. The instrument detects charged aerosols in four different mass ranges on four pairs of biased collector plates, one set for positive particles and one set for negative particles. The first sounding rocket was launched into a Polar Mesospheric Summer echo (PMSE) and into a NLC on 3 August. The solar zenith angle was 93 degrees and NLC were seen in the previous hour at 83 km by the ALOMAR RMR lidar. NLC were also detected at the same altitude by rocket-borne photometer measurements. The data from the MASS instrument shows a negatively charged population with radii >3 nm in the 83--89 km altitude range, which is collocated with PMSE detected by the ALWIN radar. Smaller particles, 1--2 nm in radius with both positive and negative polarity were detected between 86--88 km. Positively charged particles <1 nm in radius were detected at the same altitude. This is the first time the charge number densities of positive and negative NLC particles have been measured simultaneously. A charging model is developed to investigate the coexistence of positively and negatively charged aerosols in the NLC environment as measured by the MASS instrument. Natanson's rate equations are used for the attachment of free electrons and ions and the model includes charging by photo-electron emission and photo-detachment. Although the MASS flight occurred during twilight conditions, the solar UV flux was still sufficient to affect the charge state of the aerosols. The calculations are done assuming three types of particles with different photo-electron charging properties: (1) Icy NLC particles, (2) Hematite particles of meteoric origin as

  12. The impact of energetic electron precipitation on the distribution of OH and O3 in the mesosphere during weak to moderate recurrent storms in 2008

    NASA Astrophysics Data System (ADS)

    Zawedde, Annet Eva; Nesse Tyssøy, Hilde; Stadsnes, Johan; Ødegaard, Linn-Kristine; Sandanger, Marit Irene; Orsolini, Yvan

    2015-04-01

    We investigate the direct impact of Energetic Electron Precipitation (EEP) on the mesosphere constituents, OH and O3, during 2008 using data measured by the NOAA Polar Orbiting Environment Satellites (POES) and the Aura satellite. In 2008 a sequence of weak to moderate geomagnetic storms occurred triggered by high speed solar wind streams from coronal holes. OH enhancement of up to 80%/60% due to EEP is seen in the mesosphere poleward of 55oN/S CGM latitude with local maxima (hotspots). Not all hotspots appear, however, to be related to the EEP impact alone. The hotspot over North America seem to be strongly influenced by dynamical effects, whereby winter-time downwelling brings down atomic oxygen and atomic hydrogen which are important for the formation of OH at mesospheric altitudes. O3 depletions of up to 40%, due to odd hydrogen catalytic cycles were seen in both hemispheres. Our findings suggest that even during solar minimum, the EEP driven OH production can be an important driver for the O3 reduction in the mesosphere.

  13. SMILES observations of mesospheric ozone during the solar eclipse

    NASA Astrophysics Data System (ADS)

    Imai, Koji; Imamura, Takashi; Takahashi, Kenshi; Akiyoshi, Hideharu; Yamashita, Yousuke; Suzuki, Makoto; Ebisawa, Ken; Shiotani, Masato

    2015-05-01

    The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) successfully observed vertical distributions of ozone (O3) concentration in the middle atmosphere during the annular solar eclipse that occurred on 15 January 2010. In the mesosphere, where the photochemical lifetime of O3 is relatively short (approximately 100 s), altitude-dependent changes in O3 concentration under reduced solar radiation and their temporal variations were clearly observed as a function of the eclipse obscuration. This study reports the vertical distributions of mesospheric O3 during a solar eclipse event and analyzes theoretically the eclipse-induced changes. We show that simple analytical expressions for O3 concentration, which assume that O3 and O are in a photochemically steady state, can be used to describe the O3 concentration under reduced solar radiation. The SMILES data obtained during the eclipse provide a unique opportunity to test our current understanding of mesospheric O3 photochemistry.

  14. Mesospheric electron detachment and LORE recovery times

    NASA Astrophysics Data System (ADS)

    Gordillo-Vazquez, Francisco J.; Haldoupis, Christos; Luque, Alejandro

    2015-04-01

    We present new results concerning the recovery times (> 10 minutes) of LOng Recovery Early VLF events (LORE) in the upper mesosphere connected to electromagnetic pulses (EMP) of large (> 250 kA km) charge moment change (CMC) ± CG (cloud to ground) lightning capable of producing elves or elve-sprite pairs (in the case of +CG parent lightning) [1], [2]. We have modeled two possible scenarios considering first the relaxation of slightly perturbed ambient electron densities (ne0 + Δne) without an impulsive ionization source and another scenario where the ambient electron density is considerably enhanced due to an impulsive ionization source (the lightning EMP). The full non-equilibrium kinetic and 2D EMP modelling of the perturbed mesosphere in the 76 km - 92 km range during LORE occurring conditions indicates that the electron density relaxation time (defined as the time the perturbed electron density, Δne, takes to decay a factor 1/e of the way to the ambient electron density (ne0)) is critically controlled at each altitude by the relative importance of associative detachment (of O- by, respectively, O and CO and of O2- by O) with respect to electron loss mechanisms (mainly 3-body, 2-body attachment and electron-ion recombination at the highest altitudes). We found that the maximum electron density relaxation time (> 15000 s) occur between 80 km and 82 km while it decreases with increasing altitudes to 12000 s (at 85 km) and about 2000 s (at 92 km). However, LORES are presumably due to VLF scattering from electron density enhancements caused by lightning-induced EMPs in the uppermost D region ionosphere (85 - 92 km). Thus the observed VLF signal recoveries (LORE recovery times) should associate with the relaxation of the maximum enhanced electron densities produced by elves between 85 km and 92 km [3]. Finally, our results for the lowest altitudes considered (76 km and 77 km) are in good agreement with the recovery times (between 20 s and 120 s) of the typical

  15. Solar Mesosphere Explorer optical-mechanical systems engineering

    NASA Technical Reports Server (NTRS)

    Gause, K. A.; Stuart, J. R.

    1979-01-01

    Mission overview of the Solar Mesosphere Explorer is presented along with design analysis and summaries of results. The Solar Mesosphere Explorer is a spin stabilized satellite carrying a complement of four Ebert-Fastie spectrometers and a four-channel Mersenne radiometer. Description of the spectrometer is given including a telescope and its aberrations. The radiometer is also described with consideration given to isothermal and thermal design, a Winston paraboloid, and optical tolerances. These five instruments are for measuring the earth's ozone density and distribution and providing quantitative data about those processes which govern the formation and destruction of ozone.

  16. Metals in the mesosphere: chemistry and change

    NASA Astrophysics Data System (ADS)

    Plane, John; Marsh, Daniel; Höffner, Josef; Janches, Diego; Dawkins, Erin; Gomez-Martin, Juan Carlos; Bones, David; Feng, Wuhu; Chipperfield, Martyn

    2016-07-01

    The meteoric metal layers (e.g. Na, Fe, K and Ca) - which form as a result of the ablation of incoming meteors - act as unique tracers for chemical and dynamical processes that occur within the upper mesosphere/lower thermosphere region. This presentation examines whether these metal layers are sensitive indicators of longer-term changes within the upper atmosphere. Output from the Whole Atmosphere Community Climate Model (WACCM) is used to assess the response of the Na, K and Fe layers across a 50-year period (1955-2005), while both model and observational data (satellite and lidar) is used to assess the response of the Na and K layers to the 11-year solar cycle extending between 2004-2013. On short time-scales, the K layer exhibits a very different seasonal behaviour compared to the other metals. This unusual behaviour is also exhibited at longer time-scales (both the 11-yr solar cycle and 50-yr periods); K displays a much more pronounced response to atmospheric changes at a 50-yr time scale than either Na or Fe. Underpinning this modelling work are two new laboratory systems developed at Leeds. First, a time-of-flight mass spectrometer with laser photo-ionization has been used to study the reactions of neutral metallic compounds in the gas phase which are not detectable by conventional spectroscopic probes. This has enabled significant advances in Na layer chemistry to be made. The second is a flowing afterglow/laser ablation experiment which has been used to study the dissociative recombination of metallic ions such as FeO ^{+} and CaO ^{+} with electrons; these processes are particularly important for modelling the phenomenon of sporadic metal layers.

  17. Model of Semidiurnal Pseudo Tide in the High-Latitude Upper Mesosphere

    NASA Technical Reports Server (NTRS)

    Talaat, E. R.; Mayr, H. G.

    2011-01-01

    We present numerical results for the m = 1 meridional winds of semi diurnal oscillations in the high-latitude upper mesosphere, which are generated in the Numerical Spectral Model (NSM) without solar excitations of the tides. Identified with heuristic computer runs, the pseudo tides attain amplitudes that are, at times, as large as the non-migrating tides produced with standard solar forcing. Under the influence of parameterized gravity waves, the nonlinear NSM generates internal oscillations like the quasi-biennial oscillation, that are produced with periods favored by the dynamical properties of the system. The Coriolis force would favor at polar latitudes the excitation of the 12-hour periodicity. This oscillation may help explain the large non-migrating semidiurnal tides that are observed in the region with ground-based and satellite measurements.

  18. Long term variations and solar variability of atomic oxygen and hydrogen in the mesosphere / lower thermosphere

    NASA Astrophysics Data System (ADS)

    Ern, Manfred; Kaufmann, Martin; Lehmann, Catrin; Riese, Martin; Smith, Anne; Marsh, Daniel

    Global measurements of the hydroxyl mesospheric airglow as observed by the SCIAMACHY satellite instrument are presented. SCIAMACHY is mounted on ESA's Envisat launched in March 2002 into a polar, sun-synchronous orbit with an inclination of 98.7deg and an ascending node at 22:00 local solar time. Limb observations on the night side cover about 70 degrees in terms of latitude during each orbit, covering 30S-70N, depending on season. Based on these measurements altitude profiles of atomic oxygen and hydrogen are retrieved by means of an OH non-LTE model. These data are analyzed with respect to solar illumination conditions and global wave activity. A windowed space-time Fourier analysis is carried out to investigate seasonal changes in mesopause wave activity. First comparisons with simulations of the NCAR ROSE model are shown.

  19. Influence of El Nino Southern Oscillation on the Mesospheric Temperature

    NASA Technical Reports Server (NTRS)

    Li, Tao; Calvo, Natalia; Yue, Jia; Dou, Xiankang; Russell, J. M, III; Mlynczak, M. G.; She, Chiao-Yao; Xue, Xianghui

    2013-01-01

    Using the middle atmosphere temperature data set observed by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite experiment between 2002 and 2012, and temperatures simulated by the Whole Atmospheric Community Climate Model version 3.5 (WACCM3.5) between 1953 and 2005, we studied the influence of El Niño-Southern Oscillation (ENSO) on middle atmosphere temperature during the Northern Hemisphere (NH) wintertime. For the first time, a significant winter temperature response to ENSO in the middle mesosphere has been observed, with an anomalous warming of approximately 1.0 K/MEI (Multivariate ENSO Index) in the tropics and an anomalous cooling of approximately 2.0 K/MEI in the NH middle latitudes. The observed temperature responses to ENSO in the mesosphere are opposite to those in the stratosphere, in agreement with previous modeling studies. Temperature responses to ENSO observed by SABER show similar patterns to those simulated by the WACCM3.5 model. Analysis of the WACCM3.5 residual mean meridional circulation response to ENSO reveals a significant downwelling in the tropical mesosphere and upwelling in the NH middle and high latitudes during warm ENSO events, which is mostly driven by anomalous eastward gravity wave forcing in the NH mesosphere.

  20. Validation of the global distribution of CO2 volume mixing ratio in the mesosphere and lower thermosphere from SABER

    NASA Astrophysics Data System (ADS)

    Rezac, L.; Jian, Y.; Yue, J.; Russell, J. M.; Kutepov, A.; Garcia, R.; Walker, K.; Bernath, P.

    2015-12-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite has been measuring the limb radiance in 10 broadband infrared channels over the altitude range from ~ 400 km to the Earth's surface since 2002. The kinetic temperatures and CO2 volume mixing ratios (VMRs) in the mesosphere and lower thermosphere have been simultaneously retrieved using SABER limb radiances at 15 and 4.3 µm under nonlocal thermodynamic equilibrium (non-LTE) conditions. This paper presents results of a validation study of the SABER CO2 VMRs obtained with a two-channel, self-consistent temperature/CO2 retrieval algorithm. Results are based on comparisons with coincident CO2 measurements made by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) and simulations using the Specified Dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM). The SABER CO2 VMRs are in agreement with ACE-FTS observations within reported systematic uncertainties from 65 to 110 km. The annual average SABER CO2 VMR falls off from a well-mixed value above ~80 km. Latitudinal and seasonal variations of CO2 VMRs are substantial. SABER observations and the SD-WACCM simulations are in overall agreement for CO2 seasonal variations, as well as global distributions in the mesosphere and lower thermosphere. Not surprisingly, the CO2 seasonal variation is shown to be driven by the general circulation, converging in the summer polar mesopause region and diverging in the winter polar mesopause region.

  1. Mesospheric Mountain Wave Breaking and Oceanic Wave Signatures During DEEPWAVE

    NASA Astrophysics Data System (ADS)

    Taylor, M. J.; Pautet, P. D.; Fritts, D. C.; Doyle, J. D.; Eckermann, S. D.; Williams, B. P.; Kaifler, B.; Bossert, K.; Criddle, N.

    2015-12-01

    DEEPWAVE is an international program designed to quantify gravity wave (GW) dynamics and effects from the ground to the upper mesosphere in unprecedented detail utilizing a range of airborne and ground-based measurements. DEEPWAVE was based on the South Island, New Zealand, to provide access to well-documented, but little understood, New Zealand and Tasmania "hotspots" as identified in satellite stratospheric measurements. Deep orographic GWs over New Zealand were a primary target, but multiple flights were also conducted over the Southern Ocean and Tasman Sea to quantify deep GW arising from convection, jet streams, and frontal systems. This presentation highlights new airborne and ground-based results obtained using an Advanced OH Mesospheric Temperature Mapper (AMTM) which creates high-quality intensity and temperature maps of a broad spectrum of mesospheric GWs. Two AMTM's were employed, one sited at the NIWA Observatory, Lauder (45°S), on the South Island, and one on the NSF GV Gulfstream aircraft which was supplemented by two side viewing IR OH imagers providing large field, ~900 km cross-track, GW maps. These instruments formed part of a comprehensive measurements capability including airborne Rayleigh and Na lidars, dropsondes, ground-based Rayleigh lidar, all-sky imagers and wind measurements. A total of 25 long duration (typically 7-8 hours) nighttime flights were conducted creating an exceptionally rich data set. Here we focus on two key initial findings (a) discovery of large amplitude, mesospheric mountain waves and their intermittent wave breaking signatures, and (b) first measurements of large-field open-ocean mesospheric GW and their near-identical stratospheric wave signatures using AIRS satellite and model forecasting data.

  2. TIMED/SABER observations of global gravity wave climatology and their interannual variability from stratosphere to mesosphere lower thermosphere

    NASA Astrophysics Data System (ADS)

    John, Sherine Rachel; Kumar, Karanam Kishore

    2012-09-01

    The present study for the first time reports the global gravity wave activity in terms of their potential energy derived from TIMED/SABER observations right from the stratosphere to the mesosphere lower thermosphere (MLT) region. The potential energy profiles obtained from SABER temperature are validated by comparing them with ground based LIDAR observations over a low latitude site, Gadanki (13.5° N, 79.2° E). The stratospheric and mesospheric global maps of gravity wave energy showed pronounced maxima over high and polar latitudes of the winter hemisphere. The interannual variability of the stratospheric gravity wave activity exhibited prominent annual oscillation over mid-latitudes. The equatorial gravity wave activity exhibited quasi-biennial oscillation in the lower stratosphere and semi-annual oscillation in the upper stratosphere. The MLT region maps revealed summer hemispheric maxima over polar latitudes and secondary maxima over the equatorial region. The results are discussed in the light of present understanding of global gravity wave observations. The significance of the present study lies in emphasizing the importance of satellite measurements in elucidating gravity waves, which is envisaged to have profound impact on parameterizing these waves.

  3. Ground network observations of the thermosphere and the mesosphere by the Optical Mesosphere Thermosphere Imagers (OMTIs)

    NASA Astrophysics Data System (ADS)

    Shiokawa, Kazuo; Otsuka, Yuichi

    The Solar-Terrestrial Environment Laboratory, Nagoya University, has operated the Optical Mesosphere Thermosphere Imagers (OMTIs) since 1998. The OMTIs consist of 13 all-sky cooled-CCD imagers, four Fabry-Perot interferometers (FPIs), three meridian scanning pho-tometers, and four airglow temperature photometers. They measure two-dimensional pattern, Doppler wind, and temperature through airglow emissions from oxygen (wavelength: 557.7 nm) and OH (near infrared band) in the mesopause region (80-100 km) and from oxygen (630.0 nm) in the thermosphere/ionosphere (200-300 km). The OMTIs are in automatic operation at Norway, Australia, Indonesia, far-eastern Russia, four stations in Japan, and two stations in Canada. In 2010, three Fabry-Perot interferometers will be installed in Thailand, Indonesia, and Australia, to measure thermospheric neutral wind pattern at two pairs of geomagnetic conjugate stations at low latitudes. In this paper, we show some recent results obtained by OMTIs particularly for the dynamics of the medium-scale traveling ionospheric disturbances in the subauroral and equatorial latitudes.

  4. Mesospheric and stratospheric NOy produced by energetic particle precipitation during 2002-2012

    NASA Astrophysics Data System (ADS)

    Funke, B.; López-Puertas, M.; Stiller, G. P.; Clarmann, T.

    2014-04-01

    Global distributions of the six principal reactive nitrogen (NOy) compounds (HNO3, NO2, NO, N2O5, ClONO2, and HNO4) have been derived from midinfrared limb emission spectra taken by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board Envisat during 2002-2012. The obtained data set provides a unique climatological record of NOy in the middle atmosphere. The contribution of NOy produced by energetic particle precipitation (EPP) has been discriminated from that produced by N2O oxidation using a tracer correlation method based on MIPAS CH4 and CO observations. The EPP-NOy distributions, obtained in the vertical range 20-70km, allow to trace odd nitrogen polar winter descent from the mesosphere down to the middle and lower stratosphere, where it contributes to catalytic ozone destruction. Highest EPP-NOy concentrations (up to 1 ppmv) are found in the winter solstice mesosphere, decreasing continuously with time and toward lower altitudes. Springtime peak concentrations of a few parts per billion by volume are observed at 22-25km, demonstrating a regular EPP impact on the entire stratosphere. The interannual variation shows a clear solar cycle signal in consonance with geomagnetic activity variations. A pronounced hemispheric asymmetry of EPP-NOy is observed, with higher concentrations in the Southern Hemisphere (SH) and stronger variability in the Northern Hemisphere (NH). Poleward of 60°, EPP-NOy contributes to the winter NOy column at 20-70km by 10-40% in the SH and 1-30% in the NH. Smaller contributions (0.1-1%) are found at midlatitudes (30°-60°). This study provides the first assessment of EPP-NOy intrusions into the stratosphere based on globally available satellite data on a decadal scale.

  5. Trends in mesospheric ice layers in the Northern Hemisphere during 1961-2013

    NASA Astrophysics Data System (ADS)

    Berger, U.; Lübken, F.-J.

    2015-11-01

    The MIMAS ice model is used to study the trend behavior of polar mesospheric clouds (PMCs) responding to long-term changes in mesospheric temperatures at northern high latitudes for the summer period 1961-2013. This paper presents long-term PMC variations in terms of ice water content (IWC) at northern high latitudes for monthly July averages that are compared to solar backscatter ultraviolet (SBUV) data available in the period 1979-2013. In general, good agreement is found between long-term PMC variations from the model and from satellite observations. For example, both model and SBUV data show an increase in ice water content (IWC > 40 g km-2) in the latitude band 74°-82°N with significant IWC trends of 2.8 ± 2.1 g km-2/dec and 2.4 ± 2.0 g km-2/dec, respectively. Modeled trends in IWC are latitudinally dependent. For the entire period 1961-2013 no trend exists at midlatitudes (50°-60°N) but increases poleward to highly significant values of 4.4 ± 0.9 g km-2/dec in the latitude band 74°-82°N. The analysis of trends in extreme PMC events (IWC > 300 g km-2) shows a 23%/dec increase in occurrence frequency at 74°-82°N which is by far the largest trend of all PMC parameters. We discuss the statistical properties of PMC following an exponential distribution. We derive an analytic solution of ice growth from microphysics that allows calculation of ice particle radius as a function of background conditions. As a result, the thermal conditions near 83 km height, with a cooling of -0.58 ± 0.32 K/dec, mainly determine trends in IWC whereas cooling at lower heights, induced by stratospheric ozone, controls to a large extent the long-term behavior of PMC altitudes.

  6. Charging of meteoric smoke and ice particles in the mesosphere including photoemission and photodetachment rates

    NASA Astrophysics Data System (ADS)

    Knappmiller, S.; Rapp, M.; Robertson, S.; Gumbel, J.

    2011-09-01

    Charge probability distributions and charge number densities are presented for three types of particles that occur in the polar summer mesosphere: NLC particles (ice particles), meteoric smoke particles (MSP), and MSP covered in ice. Charge probability distributions and charge number densities are found using a kinetic rate equation including photoemission and photodetachment rates. Due to the large workfunction of ice, photoemission rates for NLC particles are negligible. The electron affinity for ice is an order of magnitude lower than the workfunction, thus photodetachment is a significant charging process. In the absence of photo-charging effects, an NLC particle will charge negatively by electron collection, and a particle above 10 nm in radius will have a charge that increases approximately linearly with radius. However when photodetachment is included, the number of electrons that attach to an NLC particle above 10 nm in radius is limited. Metal oxides such as Fe2O3 have been suggested as a primary constituent of MSP. Assuming that the optical properties of MSP can be represented by these metal oxides, photoemission and photodetachment rates are comparable to electron attachment rates resulting in positively charged MSP. Photoemission, therefore, may help explain the multiple observations of positive particles observed in the mesosphere. In addition, the existence of positively charged MSP has implications for the formation of NLC particles. NLC particles with a core of meteoric smoke have an increased photodetachment rate, making the mean charge of the particle less negative. NLC particles with densities larger than the electron and ion densities calculated both with and without photodetachment show the coexistence of positive and negative particles. Large number densities of NLC particles are another possible explanation for the simultaneous occurrence of positive and negative particles observed by rocket-borne instruments.

  7. The crystal structure of ice under mesospheric conditions

    NASA Astrophysics Data System (ADS)

    Murray, Benjamin J.; Malkin, Tamsin L.; Salzmann, Christoph G.

    2015-05-01

    Ice clouds form in the summer high latitude mesopause region, which is the coldest part of the Earth's atmosphere. At these very low temperatures (<150 K) ice can exist in metastable forms, but the nature of these ices remains poorly understood. In this paper we show that ice which is grown at mesospherically relevant temperatures does not have a structure corresponding to the well-known hexagonal form or the metastable cubic form. Instead, the ice which forms under mesospheric conditions is a material in which cubic and hexagonal sequences of ice are randomly arranged to produce stacking disordered ice (ice Isd). The structure of this ice is in the trigonal crystal system, rather than the cubic or hexagonal systems, and is expected to produce crystals with aspect ratios consistent with lidar observations.

  8. Report of the Ionosphere-Thermosphere-Mesosphere Panel

    NASA Technical Reports Server (NTRS)

    Szuszczewicz, Edward P.; Killeen, Tim L.; Arnoldy, Roger L.; Brace, Larry H.; Christensen, Andrew B.; Fejer, B.; Heelis, Roderick A.; Keskinen, Michael J.; Maynard, Nelson C.; Mayr, Hans G.

    1991-01-01

    The scientific objectives and mission concept that emerged from the discussions of this panel are presented. The overall scientific theme of this report is the investigation of the ionosphere, thermosphere, and mesosphere (near Earth space environment) as a global, dynamic, and coupled system. Among the specific goals of this area of research are: (1) understanding the consequences of transition between turbulent and laminar flow and collisional and collisionless media; (2) understanding the thermospheric/mesospheric coupling due to gravity wave, tidal, and trace constituent transport processes; (3) understanding the electrodynamical coupling between the thermosphere/ionosphere and magnetosphere; (4) understanding the coupling processes between small scale plasma structures; and (5) determining the real-time evolution of the global ionosphere electric field in response to solar wind and magnetosphere coupling.

  9. Equatorial Enhancement of the Nighttime OH Mesospheric Infrared Airglow

    NASA Technical Reports Server (NTRS)

    Baker, D. J.; Mlynczak, M. G.; Russell, J. M.

    2007-01-01

    Global measurements of the hydroxyl mesospheric airglow over an extended period of time have been made possible by the NASA SABER infrared sensor aboard the TIMED satellite which has been functioning since December of 2001. The orbital mission has continued over a significant portion of a solar cycle. Experimental data from SABER for several years have exhibited equatorial enhancements of the nighttime mesospheric OH (delta v = 2) airglow layer consistent with the high average diurnal solar flux. The brightening of the OH airglow typically means more H + O3 is being reacted. At both the spring and autumn seasonal equinoxes when the equatorial solar UV irradiance mean is greatest, the peak volume emission rate (VER) of the nighttime Meinel infrared airglow typically appears to be both significantly brighter plus lower in altitude by several kilometres at low latitudes compared with midlatitude findings.

  10. Equatorial enhancement of the nighttime OH mesospheric infrared airglow

    NASA Astrophysics Data System (ADS)

    Baker, D. J.; Thurgood, B. K.; Harrison, W. K.; Mlynczak, M. G.; Russell, J. M.

    2007-05-01

    Global measurements of the hydroxyl mesospheric airglow over an extended period of time have been made possible by the NASA SABER infrared sensor aboard the TIMED satellite which has been functioning since December of 2001. The orbital mission has continued over a significant portion of a solar cycle. Experimental data from SABER for several years have exhibited equatorial enhancements of the nighttime mesospheric OH (Δv=2) airglow layer consistent with the high average diurnal solar flux. The brightening of the OH airglow typically means more H+O3 is being reacted. At both the spring and autumn seasonal equinoxes when the equatorial solar UV irradiance mean is greatest, the peak volume emission rate (VER) of the nighttime Meinel infrared airglow typically appears to be both significantly brighter plus lower in altitude by several kilometres at low latitudes compared with midlatitude findings.

  11. Summary of Sessions: Ionosphere - Thermosphere - Mesosphere Working Group

    NASA Technical Reports Server (NTRS)

    Spann, J. F.; Bhattacharyya, A.

    2006-01-01

    The topics covered by the sessions under the working group on Ionosphere-Thermosphere-Mesosphere dealt with various aspects of the response of the ionosphere-thermosphere coupled system and the middle atmosphere to solar variability. There were four plenary talks related to the theme of this working group, thirteen oral presentations in three sessions and six poster presentations. A number of issues related to effects of solar variability on the ionosphere-thermosphere, observed using satellite and ground-based data including ground magnetometer observations, radio beacon studies of equatorial spread F, and modeling of some of these effects, were discussed. Radar observations of the mesosphere-lower thermosphere region and a future mission to study the coupling of thunderstorm processes to this region, the ionosphere, and magnetosphere were also presented.

  12. The accuracy of Nimbus 7 LIMS temperatures in the mesosphere

    NASA Technical Reports Server (NTRS)

    Remsberg, E. E.

    1986-01-01

    Zonal-mean temperatures from the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) experiment are compared with a temperature 'climatology' derived from 4 years of Rayleigh backscatter lidar measurements at 44 N and for the months of March, April, and May, when wave activity and thus atmospheric variability is very weak. The mean difference between the two data sets is less than 3.5 K between 37 and 64 km and is consistent with the theoretical estimates of accuracy reported for the LIMS data. The effects of longitudinal and year-to-year variaiations in this comparison were considered, but they do not change the conclusions significantly. These validation results extend the altitude range of accurate LIMS temperatures in the mesosphere some 10 km higher than previously reported. It also means the LIMS ozone and NO2 retrievals in the lower mesosphere should be free of any major temperature bias error effects.

  13. A 2-D dynamical model of mesospheric temperature inversions in winter

    SciTech Connect

    Hauchecorne, A.; Maillard, A. )

    1990-11-01

    A 2-D stratospheric and mesospheric dynamical model including drag and diffusion due to gravity wave breaking is used to simulate winter mesospheric temperature inversions similar to those observed by Rayleigh lidar. It is shown that adiabatic heating associated to descending velocities in the mesosphere is the main mechanism involved in the formation of such inversions. Sensitivity tests are performed with the model and confirm this assumption. It is also explained why other previous similar studies with 2-D models did not show mesospheric inversion layers.

  14. The evolution of a breaking mesospheric bore wave packet

    NASA Astrophysics Data System (ADS)

    Stockwell, R. G.; Taylor, M. J.; Nielsen, K.; Jarvis, M. J.

    2011-10-01

    All-sky CCD observations of mesospheric gravity waves have been made from Halley Station Antarctica (75.5°S, 26.7°W) as part of a collaborative research program between British Antarctic Survey, U.K. and Utah State University, USA. A mesospheric bore event was observed in the nightglow emissions over a period of several hours on the 27th of May, 2001. Two dimensional S-Transform (ST) analysis is applied to the airglow images of this bore event. This local spectral technique allows one to calculate the wave parameters as a function of time and space. It is observed that the horizontal phase speed and wavelength decrease over time as the amplitude attenuates. Simultaneously with this wave event the background wind experiences a large acceleration in the direction of the wave propagation. Mesospheric bore theory calculations are used to estimate the bore duct depth and it is shown that as the wave packet evolves, the bore duct collapses (decreasing in its vertical extent). As the bore duct shrinks, the wave's group velocity decelerates, the amplitude attenuates, and the wave dissipates.

  15. What anthropogenic changes are reflected in the mesospheric cloud record?

    NASA Astrophysics Data System (ADS)

    Stevens, M. H.; Englert, C. R.; Deland, M. T.

    Recent public discourse and results from data analysis have resulted in a dispute concerning layered phenomena of the mesopause region. The disagreement centers on what role, if any, anthropogenic effects play in the observed mesospheric cloud record. While some conclude that the cloud observations reflect changes initiated in the lower atmosphere, others argue that our understanding of this complex region is not yet complete enough to support this conclusion. One possible complexity is mesospheric cloud formation caused by space shuttle and rocket exhaust injected into the upper atmosphere. Regardless of viewpoint, there is currently general agreement that variations in upper atmospheric (>80 km) water vapor will play a defining role in the ultimate resolution of the dispute. We will review the prevailing theories on long-term change for this unique region of the atmosphere and critically evaluate all substantiating evidence. Particular attention will be paid to the solar backscattered ultraviolet (SBUV) data set, which is the longest satellite data set of mesospheric clouds on record with observations since the late 1970s. We will distill the most compelling observational and theoretical issues from this evolving topic and attempt to provide a benchmark for future reference.

  16. Morphology and sources of turbulence in the mesosphere during DYANA

    NASA Astrophysics Data System (ADS)

    Lubken, F.-J.; Hillert, W.; Lehmacher, G.; von Zahn, U.; Blix, T. A.; Thrane, E. V.; Widdel, H.-U.; Kokin, G. A.; Knyazev, A. K.

    1994-12-01

    During the DYnamics Adapted Network for the Atmosphere (DYANA) campaign in early 1990 turbulent parameters were measured at various places by means of in situ and ground supported techniques. Rocket borne instruments detected small-scale fluctuations of neutral (TOTAL instrument) and ion (PIP instrument) number densities in the mesosphere and lower thermosphere. A total of six flights was successfully performed in Andoya (69 deg N) and two in Biscarosse (44 deg N). Altitude profiles of turbulent parameters, such as turbulent energy dissipation rates epsilon and turbulent diffusion coefficients Kappa were derived from the fluctuations. Thanks to improvements in the instrumental capabilities, the reliability of the absolute values is unprecedented. The mean turbulent energy dissipation rates measured both by TOTAL and PIP in Andoya show very low values (less than 1 mW/kg) in the lower mesosphere, increasing to approximately 10 W/kg in the upper mesosphere. The corresponding heating rates are approximately 0.05 and 1 K/day, respectively. The two flights performed in Biscarosse showed similar low values. In addition to the in situ measurements, energy dissipation rates were measured around 75 km by the chaff dispersion technique at Heiss Island (81 deg N) and at Volgograd (48 deg N). Much higher epsilon values were observed (typically 100 mW/kg) using this procedure than those values obtained by in situ measurements.

  17. Twin mesospheric bores observed over Brazilian equatorial region

    NASA Astrophysics Data System (ADS)

    Medeiros, A. F.; Paulino, I.; Taylor, M. J.; Fechine, J.; Takahashi, H.; Buriti, R. A.; Lima, L. M.; Wrasse, C. M.

    2016-01-01

    Two consecutive mesospheric bores were observed simultaneously by two all-sky cameras on 19 December 2006. The observations were carried out in the northeast of Brazil at two different stations: São João do Cariri (36.5° W, 7.4° S) and Monteiro (37.1° W, 7.9° S), which are by about 85 km apart. The mesospheric bores were observed within an interval of ˜ 3 h in the NIR OH and OI557.7 nm airglow emissions. Both bores propagated to the east and showed similar characteristics. However, the first one exhibited a dark leading front with several trailing waves behind and progressed into a brighter airglow region, while the second bore, observed in the OH layer, was comprised of several bright waves propagating into a darker airglow region. This is the first paper to report events like these, called twin mesospheric bores. The background of the atmosphere during the occurrence of these events was studied by considering the temperature profiles from the TIMED/SABER satellite and wind from a meteor radar.

  18. Mesospheric Joule Heating During the 2003 Halloween Superstorm

    NASA Astrophysics Data System (ADS)

    Brower, L.; Thayer, J. P.; Lu, G.

    2007-12-01

    A large solar flare and coronal mass ejection produced an intense geomagnetic storm on 28-30 Oct 2003, referred to as the Halloween Storm. From 6 to 10 UT on 29 Oct 2003, the Sondrestrom incoherent scatter radar (ISR) observed enhanced high-latitude D-region electron densities and electric fields between 65 and 95 km. The observations indicate discrete enhancements of electron density associated with relativistic electron precipitation and diffuse enhancements, measuring 10x1011 m-3, due to proton precipitation. Diffuse enhancements were sustained for the four hour observing period. The large electron density, in combination with co-located electric fields observed to be in excess of 70 mV/m, leads to significant electron frictional heating. Using the TIME-GCM, it is shown that Joule heating rivals chemical and solar heating in the mesosphere during the observing period. We also demonstrate a sensitivity of mesospheric Joule heating to electron temperature, requiring the re- examination of the electron energy balance in the mesosphere.

  19. Estimating pesticide sampling rates by the polar organic chemical integrative sampler (POCIS) in the presence of natural organic matter and varying hydrodynamic conditions

    USGS Publications Warehouse

    Charlestra, Lucner; Amirbahman, Aria; Courtemanch, David L.; Alvarez, David A.; Patterson, Howard

    2012-01-01

    The polar organic chemical integrative sampler (POCIS) was calibrated to monitor pesticides in water under controlled laboratory conditions. The effect of natural organic matter (NOM) on the sampling rates (Rs) was evaluated in microcosms containing -1 of total organic carbon (TOC). The effect of hydrodynamics was studied by comparing Rs values measured in stirred (SBE) and quiescent (QBE) batch experiments and a flow-through system (FTS). The level of NOM in the water used in these experiments had no effect on the magnitude of the pesticide sampling rates (p > 0.05). However, flow velocity and turbulence significantly increased the sampling rates of the pesticides in the FTS and SBE compared to the QBE (p < 0.001). The calibration data generated can be used to derive pesticide concentrations in water from POCIS deployed in stagnant and turbulent environmental systems without correction for NOM.

  20. Choosing the polarity of the phase-encoding direction in diffusion MRI: Does it matter for group analysis?

    PubMed Central

    Kennis, M.; van Rooij, S.J.H.; Kahn, R.S.; Geuze, E.; Leemans, A.

    2016-01-01

    Notorious for degrading diffusion MRI data quality are so-called susceptibility-induced off-resonance fields, which cause non-linear geometric image deformations. While acquiring additional data to correct for these distortions alleviates the adverse effects of this artifact drastically – e.g., by reversing the polarity of the phase-encoding (PE) direction – this strategy is often not an option due to scan time constraints. Especially in a clinical context, where patient comfort and safety are of paramount importance, acquisition specifications are preferred that minimize scan time, typically resulting in data obtained with only one PE direction. In this work, we investigated whether choosing a different polarity of the PE direction would affect the outcome of a specific clinical research study. To address this methodological question, fractional anisotropy (FA) estimates of FreeSurfer brain regions were obtained in civilian and combat controls, remitted posttraumatic stress disorder (PTSD) patients, and persistent PTSD patients before and after trauma-focused therapy and were compared between diffusion MRI data sets acquired with different polarities of the PE direction (posterior-to-anterior, PA and anterior-to-posterior, AP). Our results demonstrate that regional FA estimates differ on average in the order of 5% between AP and PA PE data. In addition, when comparing FA estimates between different subject groups for specific cingulum subdivisions, the conclusions for AP and PA PE data were not in agreement. These findings increase our understanding of how one of the most pronounced data artifacts in diffusion MRI can impact group analyses and should encourage users to be more cautious when interpreting and reporting study outcomes derived from data acquired along a single PE direction. PMID:27158586

  1. Zonally symmetric tides in the mesosphere and lower thermosphere above Antarctica

    NASA Astrophysics Data System (ADS)

    Murphy, Damian; Aso, Takehiko; Fritts, Dave C.; Hibbins, Robert E.; McDonald, Adrian; Riggin, Dennis; Tsutsumi, Masaki; Vincent, Robert

    Concurrent operation of the MF radars at Davis (69S, 78E), Syowa (69S, 30E), Rothera (68S, 68W) and Scott Base (78S, 167E) in Antarctica provides unprecedented global-scale coverage of the polar wind field in the mesosphere and lower thermosphere (MLT: 80-100km) on short time scales. Coupled with a linear approximation to the latitudinal structure of atmospheric tides, it is possible to extract time series of the diurnal and semidiurnal tides at various zonal wave numbers. Such an analysis has identified non-zero zonally symmetric (wavenumber zero) tides in the meridional wind. The continuity equation, cast in spherical polar coordinates, relates the magnitude and slope (with latitude) of the zonally averaged meridional wind to the change in the vertical mass flux with height. Meridional velocity variations associated with the zonally symmetric tides should therefore drive vertical motions whose magnitude can be obtained by integrating the vertical mass flux. In this study, diurnal and semidiurnal vertical motions are predicted from MF radar derived tidal amplitudes during 2003/2004 and 2005/2006. A simple vertical transport model that combines the effects of air parcel movement and adiabatic expansion is used to predict the temperature perturbations associated with these zonally symmetric tidal components. These can then be compared to proxy temperature observations to infer the relative importance of horizontal transport and vertical motions.

  2. SOIR/VEX mesospheric aerosols observations and modelling

    NASA Astrophysics Data System (ADS)

    Wilquet, Valérie; Carine Vandaele, Ann; Drummond, Rachel; Mahieux, Arnaud; Robert, Séverine; Daerden, Frank; Neary, Lori; Bertaux, Jean-Loup

    2013-04-01

    SPICAV/SOIR on-board Venus Express is able to target the layer of aerosols above the cloud layer at the terminator (Wilquet et al., 2009). A high temporal variability in the aerosol content in Venus' atmosphere was inferred from SOIR observations, as well as a latitudinal dependency of the aerosol loading (Wilquet et al., 2012). This is in agreement with results from previous missions and with the facts that (i) H2SO4 aerosol particles are formed through SO2 photo-oxidation and hydration at the cloud top of Venus, (ii) SO2 photolysis is more efficient at low latitudes, (iii) the altitude of the cloud top is up to one scale height lower in the polar region than at the equator. A increasing SO2 abundance with increasing altitude was recently observed with SPICAV-UV at altitudes of ~ 85-105 km (Belyaev et al., 2012) but also from microwave ground-based spectra in the Venus mesosphere (Sandor et al., 2010), which suggest a source of SO2 at high altitudes. Zhang et al. (2012) proposed a one dimensional photochemistry-diffusion model in order to reconcile these puzzling findings; he suggested that H2SO4 might be a source of SO2 above 90 km through aerosol evaporation followed by SO3 photolysis. This model and the observations are however disputed by others demonstrating the necessity for a more global interpretation of the observations and for modelling of the upper haze layer. For example, the variations in aerosol loading can be compared to other key parameters of the atmosphere retrieved from the same SOIR spectra such as water and SO2 composition or temperature. In addition, a microphysical model is being developed that will calculate the time dependent haze particle size distributions assuming an initial size distribution of background sulphate aerosols. The model will simulate the formation, growth, evaporation, and sedimentation of particles. Results of this on-going research will be presented and discussed. References : Belyaev, D.A., F. Montmessin, J.-L. Bertaux

  3. Impact of horizontal transport, temperature, and PMC uptake on mesospheric Fe at high latitudes

    NASA Astrophysics Data System (ADS)

    Gardner, Chester S.; Huang, Wentao

    2016-06-01

    We analyze year-round Fe lidar observations made in Antarctica at Rothera (67.7°S), South Pole (90°S), and McMurdo (77.8°S). During midsummer, when the mesopause region is continuously sunlit, the Fe density between 84 and 88 km is independent of temperature, because photolysis of FeOH is so fast that virtually all of the FeOH is converted to Fe via this path, rather than via the temperature-dependent FeOH + H reaction. The extremely low summertime densities at Rothera and South Pole are caused primarily by meridional transport northward out of the polar cap and, to a lesser extent, by uptake of Fe species on polar mesospheric cloud (PMC) ice particles. In midwinter, both meridional transport and temperature dominate Fe variations. The temperature sensitivity of Fe during winter is 2.2%/K at Rothera and 3.0%/K at South Pole. The annual mean Fe abundance at McMurdo is more than 50% larger than that observed at any other lidar site in both the Northern and Southern Hemispheres. McMurdo is located at the magnetic poleward edge of the auroral oval, just north of the deep polar cap. We hypothesize that southward transport of Fe+ out of the auroral oval in winter and northward transport of Fe+ out of the deep polar cap and auroral zone in summer, to McMurdo where it is neutralized, could be the source of the enhanced Fe. Theoretical calculations show that Fe+ densities of ~13,000 cm-3 in midwinter and ~1600 cm-3 in midsummer, between 84 and 88 km, are required to account for the high Fe densities at McMurdo.

  4. The impact of energetic electron precipitation on mesospheric OH and O3 during weak to moderate recurrent geomagneic storms in 2008

    NASA Astrophysics Data System (ADS)

    Stadsnes, Johan; Nesse Tyssøy, Hilde; Zawedde, Annet Eva; Glesnes Ødegaard, Linn-Kristine; Sandanger, Marit Irene; Orsolini, Yvan

    2015-04-01

    We investigate the impact of energetic electron precipitation (EEP) on mesospheric OH during 2008 using data measured by the NOAA Polar Orbiting Environmental Satellites (POES) and the AURA satellite.The MEPED particle spectrometers on the POES include two collimated electron detectors, which are pointing approximately towards zenith and in the horizontal plane, respectively. At medium and high geomagnetic latitudes one detector measures particle within the bounce loss cone and the other detector measures particles outside or near the edge of the loss cone. The electron fluxes often show strong pitch angle anisotropy which causes large uncertainty in the estimate of energy deposition based on these measurements. To overcome this problem, we have used a method for calculating the flux versus pitch angle in the loss cone based on the measured electron fluxes and modeled flux profiles from pitch angle scattering by wave particle interactions.We calculate the electron energy deposition based on the estimated fluxes and compare the result with the mesospheric OH composition measured by AURA during a sequence of weak to moderate geomagnetic storms in 2008. Significant OH enhancement is seen both in the northern and southern hemispheres poleward of 55 degrees CGM latitude. O3 depletions due to odd hydrogen catalytic cycles were seen in both hemispheres. Our findings emphasize the importance of the EEP effect on mesospheric ozone even during minimum solar activity.

  5. Satellite observations and modelling of transport in the upper troposphere through the lower mesosphere during the 2006 major stratospheric sudden arming

    NASA Astrophysics Data System (ADS)

    Manney, G. L.; Harwood, R. S.; MacKenzie, I. A.; Minschwaner, K.; Allen, D. R.; Santee, M. L.; Walker, K. A.; Hegglin, M. I.; Lambert, A.; Pumphrey, H. C.; Bernath, P. F.; Boone, C. D.; Schwartz, M. J.; Livesey, N. J.; Daffer, W. H.; Fuller, R. A.

    2009-04-01

    An unusually strong and prolonged stratospheric sudden warming (SSW) in January 2006 was the first major SSW for which globally distributed long-lived trace gas data are available covering the upper troposphere through the lower mesosphere. We use Aura Microwave Limb Sounder (MLS), Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) data, the SLIMCAT Chemistry Transport Model (CTM), and assimilated meteorological analyses to provide a comprehensive picture of transport during this event. The upper tropospheric ridge that triggered the SSW was associated with an elevated tropopause and layering in trace gas profiles in conjunction with stratospheric and tropospheric intrusions. Anomalous poleward transport (with corresponding quasi-isentropic troposphere-to-stratosphere exchange at the lowest levels studied) in the region over the ridge extended well into the lower stratosphere. In the middle and upper stratosphere, the breakdown of the polar vortex transport barrier was seen in a signature of rapid, widespread mixing in trace gases, including CO, H2O, CH4 and N2O. The vortex broke down slightly later and more slowly in the lower than in the middle stratosphere. In the middle and lower stratosphere, small remnants with trace gas values characteristic of the pre-SSW vortex lingered through the weak and slow recovery of the vortex. The upper stratospheric vortex quickly reformed, and, as enhanced diabatic descent set in, CO descended into this strong vortex, echoing the fall vortex development. Trace gas evolution in the SLIMCAT CTM agrees well with that in the satellite trace gas data from the upper troposphere through the middle stratosphere. In the upper stratosphere and lower mesosphere, the SLIMCAT simulation does not capture the strong descent of mesospheric CO and H2O values into the reformed vortex; poor CTM performance in the upper stratosphere and lower mesosphere results primarily from biases in the diabatic descent in assimilated

  6. Satellite observations and modeling of transport in the upper troposphere through the lower mesosphere during the 2006 major stratospheric sudden warming

    NASA Astrophysics Data System (ADS)

    Manney, G. L.; Harwood, R. S.; MacKenzie, I. A.; Minschwaner, K.; Allen, D. R.; Santee, M. L.; Walker, K. A.; Hegglin, M. I.; Lambert, A.; Pumphrey, H. C.; Bernath, P. F.; Boone, C. D.; Schwartz, M. J.; Livesey, N. J.; Daffer, W. H.; Fuller, R. A.

    2009-07-01

    An unusually strong and prolonged stratospheric sudden warming (SSW) in January 2006 was the first major SSW for which globally distributed long-lived trace gas data are available covering the upper troposphere through the lower mesosphere. We use Aura Microwave Limb Sounder (MLS), Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) data, the SLIMCAT Chemistry Transport Model (CTM), and assimilated meteorological analyses to provide a comprehensive picture of transport during this event. The upper tropospheric ridge that triggered the SSW was associated with an elevated tropopause and layering in trace gas profiles in conjunction with stratospheric and tropospheric intrusions. Anomalous poleward transport (with corresponding quasi-isentropic troposphere-to-stratosphere exchange at the lowest levels studied) in the region over the ridge extended well into the lower stratosphere. In the middle and upper stratosphere, the breakdown of the polar vortex transport barrier was seen in a signature of rapid, widespread mixing in trace gases, including CO, H2O, CH4 and N2O. The vortex broke down slightly later and more slowly in the lower than in the middle stratosphere. In the middle and lower stratosphere, small remnants with trace gas values characteristic of the pre-SSW vortex lingered through the weak and slow recovery of the vortex. The upper stratospheric vortex quickly reformed, and, as enhanced diabatic descent set in, CO descended into this strong vortex, echoing the fall vortex development. Trace gas evolution in the SLIMCAT CTM agrees well with that in the satellite trace gas data from the upper troposphere through the middle stratosphere. In the upper stratosphere and lower mesosphere, the SLIMCAT simulation does not capture the strong descent of mesospheric CO and H2O values into the reformed vortex; this poor CTM performance in the upper stratosphere and lower mesosphere results primarily from biases in the diabatic descent in assimilated

  7. The Mesosphere / Lower Thermosphere Lidar Mission -a study of the possibilities.

    NASA Astrophysics Data System (ADS)

    Rees, David; Armandillo, Errico; Plane, John M. C.; Saunders, Christopher J.; Foster, Mike

    A Space Lidar Mission to study the mesosphere and lower thermosphere can open up a wide range of precise measurements of a region of the atmosphere that is still very poorly known. We summarise the target measurements and the achievable goals in terms of wind, tempera-ture and species density measurements in the mesosphere / lower thermosphere regions of the atmosphere.

  8. Interaction of polar and nonpolar organic pollutants with soil organic matter: sorption experiments and molecular dynamics simulation.

    PubMed

    Ahmed, Ashour A; Thiele-Bruhn, Sören; Aziz, Saadullah G; Hilal, Rifaat H; Elroby, Shaaban A; Al-Youbi, Abdulrahman O; Leinweber, Peter; Kühn, Oliver

    2015-03-01

    The fate of organic pollutants in the environment is influenced by several factors including the type and strength of their interactions with soil components especially SOM. However, a molecular level answer to the question "How organic pollutants interact with SOM?" is still lacking. In order to explore mechanisms of this interaction, we have developed a new SOM model and carried out molecular dynamics (MD) simulations in parallel with sorption experiments. The new SOM model comprises free SOM functional groups (carboxylic acid and naphthalene) as well as SOM cavities (with two different sizes), simulating the soil voids, containing the same SOM functional groups. To examine the effect of the hydrophobicity on the interaction, the organic pollutants hexachlorobenzene (HCB, non-polar) and sulfanilamide (SAA, polar) were considered. The experimental and theoretical investigations explored four major points regarding sorption of SAA and HCB on soil, yielding the following results. 1--The interaction depends on the SOM chemical composition more than the SOM content. 2--The interaction causes a site-specific adsorption on the soil surfaces. 3--Sorption hysteresis occurs, which can be explained by inclusion of these pollutants inside soil voids. 4--The hydrophobic HCB is adsorbed on soil stronger than the hydrophilic SAA. Moreover, the theoretical results showed that HCB forms stable complexes with all SOM models in the aqueous solution, while most of SAA-SOM complexes are accompanied by dissociation into SAA and the free SOM models. The SOM-cavity modeling had a significant effect on binding of organic pollutants to SOM. Both HCB and SAA bind to the SOM models in the order of models with a small cavity>a large cavity>no cavity. Although HCB binds to all SOM models stronger than SAA, the latter is more affected by the presence of the cavity. Finally, HCB and SAA bind to the hydrophobic functional group (naphthalene) stronger than to the hydrophilic one (carboxylic acid

  9. Metals in the mesosphere: meteoroids, satellite retrievals and modelling

    NASA Astrophysics Data System (ADS)

    Dawkins, E.; Plane, J. M.; Chipperfield, M.; FENG, W.; Gumbel, J.; Hedin, J.; Höffner, J.; Friedman, J. S.

    2013-12-01

    Changes in the mesosphere may be an important signal of climate change and there is increasing evidence that accurate simulations of changes to the Earth's climate require models with a well resolved and accurate stratosphere and mesosphere. Following the ablation of meteoroids, the resulting metal species which are injected into the mesosphere/lower thermosphere region (80-110 km) offer a unique way of observing this region and of testing the accuracy of climate models in this domain. An earlier sodium retrieval algorithm has been extended, and modified to retrieve potassium densities using data from the OSIRIS spectrometer on-board the Odin satellite. Here we present an overview of the new potassium retrieval scheme, along with the first ever climatology of the global potassium layer from space for 2004-2012. These layers have been validated using lidar data and successfully capture the unusual semi-annual seasonal behaviour of potassium, which is starkly different to the other metals. Unlike sodium and iron which both display early wintertime density maxima, potassium also displays a summertime maximum which points to some unique and surprising features in the chemistry and the way it interacts with other atmospheric species. A detailed potassium chemistry scheme, developed by a team at Leeds (modules for Na, Fe, Ca, Si and Mg already added), has now been included in a version of the NCAR Whole Atmosphere Community Climate Model (WACCM). The annual, latitudinal and long-term variation of these modelled potassium layers are compared with the retrieved datasets to evaluate model chemistry and dynamics.

  10. Mesospheric observations by a forward scattering meteor radar basic setup

    NASA Astrophysics Data System (ADS)

    Madkour, Waleed; Yamamoto, Masa-yuki

    2016-08-01

    The durations of radio echo signals scattered from meteor ionized trails might not show a consistent increase corresponding to higher density trails due to the rapid removal of meteor ions at certain heights. Several studies have concluded the dominant role of the secondary ozone layer over diffusion in the removal of the meteor trails below 95 km through chemical oxidization of the meteor ions. Using a basic setup configuration of a forward scattering receiver, a trial to observe the mesospheric ozone concentration was performed by analyzing the meteor echo duration distributions. The forward scattered meteor echoes have the advantage of long durations that can enable observing the transition from the diffusion-removal regime to the chemistry-removal regime. The cumulative meteor echo duration distribution of two meteor showers, the Perseids and the Geminids, were analyzed over 10 years and the chemistry-removal regime in each shower was observed. The knee duration position at which a drop in the number of long overdense meteor echoes starts differed by around 30 seconds between the two showers. As the secondary ozone concentration is inversely related to the solar activity level, the Geminids 2011 corresponding to a high solar activity level showed a significant higher counts of long duration echoes compared to the Geminids 2006 during a low activity level, with the knee position shifted to longer duration. The knee positions obtained during the two distinct meteor showers and the two half solar cycle points are generally in agreement with the mesospheric ozone conditions expected in each case. However, continuous data record is required for the other meteor showers and the sporadic meteors at different heights to observe the mesospheric ozone concentration vertically and the full 11-years solar cycle.

  11. In situ measurements of the mesosphere and stratosphere

    NASA Technical Reports Server (NTRS)

    Crosky, C.

    1976-01-01

    The operation of a subsonic, Gerdien condenser probe for in situ measurements of the mesosphere and stratosphere is presented. The inclusion of a flashing Lyman alpha ultraviolet source provides an artifically produced ionization of particular constituents. Detailed theory of operation is presented and the data results from two flights are shown. A great deal of fine structure in mobility is observed due to the presence of various hydrated positive ions. The effect of the Lyman alpha source in the 35 km region was to dissociate a light hydrate ion rather than produce additional ionization. At the 70 km region, photodissociation of the heaviest ions (probably ice crystals) was also observed.

  12. Radiometric remote sensing of mesospheric and stratospheric water vapor

    NASA Technical Reports Server (NTRS)

    Croskey, Charles L.; Olivero, John J.; Martone, Joseph P.

    1991-01-01

    The remote sensing of stratospheric and mesospheric water vapor by microwave and millimeter radiometry is described. The received radiation is emitted by and interacts with all levels of the atmosphere. The pressure dependence of the linewidth for the absorption cross section of water vapor permits retrieval of vapor mixing ratios. The 183.31-GHz line of water vapor can also be used for remote sensing of the water vapor concentration in the upper atmosphere, but due to the much stronger absorption cross section for this line, ground-based observations are difficult. To date all measurements at 183 GHz have been made from platforms above the troposphere.

  13. A superposed epoch study of the effects of solar wind stream interface events on the upper mesospheric and lower thermospheric temperature

    NASA Astrophysics Data System (ADS)

    Ogunjobi, O.; Sivakumar, V.; Sivla, W. T.

    2014-11-01

    The response of mesosphere and lower thermosphere (MLT) temperature to energetic particle precipitation over the Earth’s polar regions is not uniform due to complex phenomena within the MLT environment. Nevertheless, the modification of MLT temperatures may require an event-based study to be better observed. This work examines the influence of precipitation, triggered by solar wind stream interfaces (SI) event from 2002 to 2007, on polar MLT temperature. We first test the relationship between the ionospheric absorption measured by the SANAE IV (South African National Antarctic Expedition IV) riometer and the layer of energetic particle precipitation from POES (Polar Orbiting Environmental Satellites). The combined particle measurements from POES 15, 16, 17 and 18 were obtained close in time to the pass of the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) temperature retrieval. Here, a superposed epoch technique is described and implemented to obtain average temperature profiles during SI-triggered particle precipitation. The superposed epoch average shows no significant temperature decrease below 100 km prior to the onset of SI-triggered precipitation, whereas a clear superposed average temperature decrease is observed at 95 km after the SI impact. A case study of SI event also yields similar observations. Results indicate that cooling effects due to the production of mesospheric odd hydrogen might be major contributors to temperature decrease under compressed solar wind stream.

  14. Wintertime Polar Ozone Evolution during Stratospheric Vortex Break-Down

    NASA Astrophysics Data System (ADS)

    Tweedy, O.; Limpasuvan, V.; Smith, A. K.; Richter, J. H.; Orsolini, Y.; Stordal, F.; Kvissel, O.

    2011-12-01

    Stratospheric Sudden Warming (SSW) is characterized by the rapid warming of the winter polar stratosphere and the weakening of the circumpolar flow. During the onset of a major SSW (when the circumpolar flow reverses direction), the warm stratopause layer (SL) descends from its climatological position to the mid-stratosphere level. As the vortex recovers from SSW, a "new" SL forms in the mid-mesosphere region before returning to its typical level. This SL discontinuity appears in conjunction with enhanced downward intrusion of chemical species from the lower thermosphere/upper mesosphere to the stratosphere. The descended species can potentially impact polar ozone. In this study, the NCAR's Whole Atmosphere Community Climate Model (WACCM) is used to investigate the behavior of polar ozone related to major SSWs. Specifically, dynamical evolution and chemistry of NOx, CO, and O3 are examined during three realistic major SSWs and compared with a non-SSW winter season. The simulated (zonal-mean) polar ozone distribution exhibits a "primary" maximum near 40 km, a "secondary" maximum between 90-105 km, and a "tertiary" maximum near 70 km. The concentration of the secondary maximum reduces by ~1.5 parts per million by volume (ppmv) as the vortex recovers and the upper mesospheric polar easterlies return. Enhanced downwelling above the newly formed SL extends up to just above this secondary maximum (~110 km). With an averaged concentration of 2 ppmv, the tertiary ozone maximum layer displaces upward with enhanced upwelling during SSW in conjunction with the lower mesospheric cooling. The downward propagation of the stratospheric wind reversal is accompanied by CO intrusion toward the lowermost stratosphere and anomalous behavior in the primary ozone maximum. Overall, the major SSW, SL, and polar ozone evolution mimic recently reported satellite observations.

  15. Mesosphere-to-stratosphere descent of odd nitrogen in February-March 2009 after sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Salmi, S.-M.; Verronen, P. T.; Thölix, L.; Kyrölä, E.; Backman, L.; Karpechko, A. Yu.; Seppälä, A.

    2011-05-01

    We use the 3-D FinROSE chemistry transport model (CTM) and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) observations to study connections between atmospheric dynamics and middle atmospheric NOx (NOx = NO + NO2) distribution. Two cases are considered in the northern polar regions: (1) descent of mesospheric NOx in February-March 2009 after a major sudden stratospheric warming (SSW) and, for comparison, (2) early 2007 when no NOx descent occurred. The model uses the European Centre for Medium-Range Weather Forecasts (ECMWF) operational data for winds and temperature, and we force NOx at the model upper altitude boundary (80 km) with ACE-FTS observations. We then compare the model results with ACE-FTS observations at lower altitudes. For the periods studied, geomagnetic indices are low, which indicates absence of local NOx production by particle precipitation. This gives us a good opportunity to study effects of atmospheric transport on polar NOx. The model results show no NOx descent in 2007, in agreement with ACE-FTS. In contrast, a large amount of NOx descends in February-March 2009 from the upper to lower mesosphere at latitudes larger than 60° N, i.e. inside the polar vortex. Both observations and model results suggest NOx increases of 150-200 ppb (i.e. by factor of 50) at 65 km due to the descent. However, the model underestimates the amount of NOx around 55 km by 40-60 ppb. According to the model results, chemical loss of NOx is insignificant during the descent period, i.e. polar NOx is mainly controlled by dynamics. The descent is terminated and the polar NOx amounts return to pre-descent levels in mid-March, when the polar vortex breaks. The break-up prevents the descending NOx from reaching the upper stratosphere, where it could participate in catalytic ozone destruction. Both ACE-FTS observations and FinROSE show a decrease of ozone of 20-30 % at 30-50 km from mid-February to mid-March. In the model, these ozone changes are not

  16. Bite-outs and other depletions of mesospheric electrons

    PubMed Central

    Friedrich, Martin; Rapp, Markus; Plane, John M.C.; Torkar, Klaus M.

    2011-01-01

    The ionised mesosphere is less understood than other parts of the ionosphere because of the challenges of making appropriate measurements in this complex region. We use rocket borne in situ measurements of absolute electron density by the Faraday rotation technique and accompanying DC-probe measurements to study the effect of particles on the D-region charge balance. Several examples of electron bite-outs, their actual depth as well as simultaneous observations of positive ions are presented. For a better understanding of the various dependencies we use the ratio β/αi (attachment rate over ion–ion recombination coefficient), derived from the electron and ion density profiles by applying a simplified ion-chemical scheme, and correlate this term with solar zenith angle and moon brightness. The probable causes are different for day and night; recent in situ measurements support existing hypotheses for daytime cases, but also reveal behaviour at night hitherto not reported in the literature. Within the large range of β/αi values obtained from the analysis of 28 high latitude night flights one finds that the intensity of scattered sunlight after sunset, and even moonlight, apparently can photodetach electrons from meteoric smoke particles (MSP) and molecular anions. The large range of values itself can best be explained by the variability of the MSPs and by occasionally occurring atomic oxygen impacting on the negative ion chemistry in the night-time mesosphere under disturbed conditions. PMID:27570472

  17. Modeling Study of Mesospheric Planetary Waves: Genesis and Characteristics

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G.; Talaat, E. L.; Porter, H. S.; Chan, K. L.

    2003-01-01

    In preparation for the measurements from the TIMED mission and coordinated ground based observations, we discuss results for the planetary waves (PWs) that appear in our Numerical Spectral Model (NSM). The present model accounts for a tropospheric heat source in the zonal mean (m = 0), which reproduces qualitatively the observed zonal jets near the tropopause and the accompanying reversal in the latitudinal temperature variations. We discuss the PWs that are solely generated internally, i.e., without the explicit excitation sources related to tropospheric convection or topography. Our analysis shows that PWs are not produced when the zonally averaged heat source into the atmosphere is artificially suppressed, and that the PWs generally are significantly weaker when the tropospheric source is not applied. Instabilities associated with the zonal mean temperature, pressure and wind fields, which still need to be explored, are exciting PWs that have amplitudes in the mesosphere comparable to those observed. Three classes of PWs are generated in the NSM. (1) Rossby waves, (2) Rossby gravity waves propagating westward at low latitudes, and (3) Eastward propagating equatorial Kelvin waves. A survey of the PWs reveals that the largest wind amplitudes tend to occur below 80 km in the winter hemisphere, but above that altitude they occur in the summer hemisphere where the amplitudes can approach 50 meters per second. It is shown that the non-migrating tides in the mesosphere, generated by non-linear coupling between migrating tides and PWs, are significantly larger for the model with the tropospheric heat source.

  18. Bite-outs and other depletions of mesospheric electrons

    NASA Astrophysics Data System (ADS)

    Friedrich, Martin; Rapp, Markus; Plane, John M. C.; Torkar, Klaus M.

    2011-09-01

    The ionised mesosphere is less understood than other parts of the ionosphere because of the challenges of making appropriate measurements in this complex region. We use rocket borne in situ measurements of absolute electron density by the Faraday rotation technique and accompanying DC-probe measurements to study the effect of particles on the D-region charge balance. Several examples of electron bite-outs, their actual depth as well as simultaneous observations of positive ions are presented. For a better understanding of the various dependencies we use the ratio β/αi (attachment rate over ion-ion recombination coefficient), derived from the electron and ion density profiles by applying a simplified ion-chemical scheme, and correlate this term with solar zenith angle and moon brightness. The probable causes are different for day and night; recent in situ measurements support existing hypotheses for daytime cases, but also reveal behaviour at night hitherto not reported in the literature. Within the large range of β/αi values obtained from the analysis of 28 high latitude night flights one finds that the intensity of scattered sunlight after sunset, and even moonlight, apparently can photodetach electrons from meteoric smoke particles (MSP) and molecular anions. The large range of values itself can best be explained by the variability of the MSPs and by occasionally occurring atomic oxygen impacting on the negative ion chemistry in the night-time mesosphere under disturbed conditions.

  19. HRDI Observations of Inertia-Gravity Waves in the Mesosphere and Lower Thermosphere

    NASA Technical Reports Server (NTRS)

    Lieberman, Ruth S.

    1999-01-01

    Vertical profiles of High-resolution Doppler imager (HRDI) mesospheric winds have small-scale structure (vertical wavelengths between 10 and 20 km) that is virtually always present. Fourier analysis of HRDI zonal and meridional wind profiles have been carried out, and the spectral characteristics are sorted by latitude, month and local time. Power spectral density (PSD) exhibits a universal exp(-km) structure in the 10-20km wavelength regime, with K lying between 2 and 3. The observed PSD for wavelengths between 10 and 20 km is a factor of 3 higher than a null spectrum constructed from HRDI reported error bars multiplied by randomly varying numbers between -1 and +1. Stokes parameters were consolidated by month into Northern and Southern hemisphere middle and high latitudes belts (40-72 degrees), tidal belts (32-16 degrees) and a tropical belt (8S-8N). Vertical waves between 10 and 15 km in wavelength are about 10-15% polarized everywhere. The inferred propagation direction in the middle and high latitude Southern hemisphere is predominantly meridional during solstice, and significantly more zonal during equinoxes. In the tropical belt, the wave orientations are nearly North-South during solstices, with a slightly higher east-west component during equinox. In the tidal belts where the background wind includes a strong meridional tidal wind, the preferred wave orientation has a significant zonal component during equinox. These findings are consistent with the interpretation of wave filtering by the background wind.

  20. Joule heating in the mesosphere and thermosphere during the July 13, 1982, solar proton event

    NASA Technical Reports Server (NTRS)

    Roble, R. G.; Emery, B. A.; Garcia, R. R.; Killeen, T. L.; Hays, P. B.; Reid, G. C.; Solomon, S.; Evans, D. S.; Spencer, N. W.; Brace, L. H.

    1987-01-01

    The solar proton event of July 13, 1982 produced considerable ionization in the polar-cap mesosphere. Energetic solar proton fluxes were measured by the NOAA-6 satellite. The DE-2 satellite measured the low-energy electrons, the ion drift velocity, and other atmospheric and ionospheric properties during the event in the region of the measured maximum electric field (189 mV/m at 2215 UT near 60 deg N), a Joule heating rate of 1-3 K/day is calculated between 70 and 80 km, exceeding the heating due to ozone absorption at noon in the summer hemisphere in that altitude range. The Joule heating rate above 90 km greatly exceeded 20 K/day. The calculated height-integrated Joule heating rate above 100 km in the same region exceeded 400 ergs/sq cm sec, and DE-2 near 350 km measured neutral winds of nearly 1000 m/s and neutral gas temperatures of over 2000 K. The overall ionospheric structure calculated below the DE-2 satellite is described.

  1. Detection of mesospheric gravity waves in Odin/OSIRIS PMC data in 2002- 2008

    NASA Astrophysics Data System (ADS)

    Petelina, S. V.; Rusch, D. W.

    2008-12-01

    The Optical Spectrograph and InfraRed Imager System instrument (OSIRIS) on the limb-viewing Odin satellite observes Polar Mesospheric Clouds (PMCs) in both hemispheres since November, 2001. The orbit period of Odin is 96 minutes and the maximum latitudinal coverage in the orbit plane is between 82.2 N and 82.2 S. In this work, the longitudinal distribution of Odin/OSIRIS PMC brightness in each hemisphere during a 4-week period around the summer solstice from 2002 until 2008 is analysed. In the Northern Hemisphere, the PMC brightness around 60+-20 W and around 80+-20 E is up to 30 percent lower than that at other longitudes. In the Southern Hemisphere, the cloud brightness is also 30-60 percent lower around 80+-20 W. We attribute this effect to the influence of gravity waves generated by the Earth's terrain above Greenland and Ural mountains (the natural boundary between Europe and Asia) in the Northern Hemisphere and by the Antarctic Peninsula mountains in the Southern Hemisphere.

  2. The content and composition of meteoric smoke in mesospheric ice particles from SOFIE observations

    NASA Astrophysics Data System (ADS)

    Hervig, Mark E.; Deaver, Lance E.; Bardeen, Charles G.; Russell, James M.; Bailey, Scott M.; Gordley, Larry L.

    2012-08-01

    This work provides the first observational evidence that ice particles comprising polar mesospheric clouds (PMC) contain small amounts of meteoric smoke (0.01-3% by volume), using measurements from the Solar Occultation For Ice Experiment (SOFIE). PMC observations at wavelengths from the ultraviolet through the infrared are inconsistent with pure ice, but can be explained in terms of the extinction simulated for a mixture of ice and meteoric smoke. Simulations of ice-smoke mixtures considered 25 different smoke compositions. The PMC observations were consistent with smoke composed of carbon (C), wüstite (FeO), or magnesiowüstite (MgxFe1-xO, x=0.1-0.6), and inconsistent with the other compositions. A method was established for simultaneously retrieving PMC particle size and the volume fraction of smoke in ice using SOFIE observations at multiple wavelengths. Compared to assuming pure ice, SOFIE retrievals considering ice-smoke mixtures yield smaller ice radii (24%) and higher concentrations (137%).

  3. A case of sudden variation in nocturnal mesospheric temperatures: variability and its causative mechanism

    NASA Astrophysics Data System (ADS)

    Taori, Alok; Kesarkar, Amit; Kumar, Niranjan; Thokuluwa, Ramkumar

    In general, nocturnal mesospheric temperatures show long period tidal oscillations to dominate in the night-time airglow observations due to its natural variability. However various forcing owing to thermally or mechanically generated waves in the lower atmosphere have been under-stood to perturb the mesospheric variability. It is also observed that the convective episode occurred in the lower atmosphere are responsible to perturb the frequency of waves observed over mesosphere. In this work, we analyze nocturnal observations recorded by mesosphere lower thermosphere photometer (MLTP) on April 21, 22 and 27, 2009 over Gadanki (13.5 N, 79.2 E), Andhra Pradesh, India. It is observed that due to the passage of cyclone Bijili during the above men-tioned period and convections observed over Indian subcontinent generated from its remnants cause the generation of period waves in the mesosphere. It is noted that the nature of OH and O2 nocturnal variation reversed on the nights of 27th compared to the 22nd and 23rd April. To understand the vertical transport of the energy in terms of short period wave we have analyzed the COSMIC (constellation observing system for meteorology ionosphere climate) temperature profiles of normalized temperature perturbations and OLR (outgoing long-wave radiation) mea-surements. The results obtained from this clearly indicate that energy flux inflow in mesosphere from lower atmosphere is caused by ongoing troposphere disturbed the mesosphere.

  4. The Mesosphere-Lower Thermosphere Turbulence Experiment (MTeX)

    NASA Astrophysics Data System (ADS)

    Collins, R. L.; Barjatya, A.; Lehmacher, G. A.; Fritts, D. C.; Luebken, F.

    2013-12-01

    The Mesosphere-Lower Thermosphere Turbulence Experiment (MTeX), is designed is to contribute to answering one of the key questions in solar-terrestrial science: How do meteorological processes control the impact of solar processes on the Earth's atmosphere? The goal of MTeX is to answer the specific question: What is the contribution of wave-generated turbulence to energetics and mixing in the mesosphere and lower thermosphere (MLT) in the presence of persistent regions of stability and instability? During recent Arctic winters, satellite observations have revealed significant transport of nitrogen oxides (produced by energetic particle precipitation) downward from the thermosphere into the mesosphere, stratosphere and ozone layer. These events have been associated with sudden stratospheric warming events (SSWs) where strong downward transport is observed in the recovery phase of the SSW. However, simulations with current coupled chemistry circulation models indicate that the observed transport cannot be explained by mean flow advection alone. Simulation of the observed transport of nitrogen oxides requires diffusive transport from the thermosphere where the magnitude of the diffusive transport is on order of the mean flow transport. Turbulence is both characterized and measured in terms of energy dissipation rates (used in circulation studies) and eddy diffusion coefficients (used in chemical transport studies). Variability over several orders of magnitude has been reported in turbulence measurements due to both the variety of background conditions present and methods used. High-resolution fluid dynamic simulations continue to raise questions about the physical and statistical assumptions used in determining turbulent characteristics. We propose to make repeated measurements of turbulence in the presence of a Mesospheric Inversion Layer (MIL) in January-February 2015 at Poker Flat Research Range, Chatanika, Alaska. The MIL (~70-90 km) and gravity wave activity in

  5. Mesospheric Zonal Mean Winds Derived from Consecutive Orbits of AIM Cips Images

    NASA Astrophysics Data System (ADS)

    Rong, P. P.; Yue, J.; Russell, J. M., III; Lumpe, J. D., Jr.; Gong, J.; Wu, D. L.; Randall, C. E.

    2014-12-01

    In order to infer mesospheric wind velocities, polar mesospheric cloud (PMC) pattern variations are investigated using images from consecutive orbits taken by the Cloud Imaging and Particle Size instrument (CIPS) aboard the AIM satellite. CIPS measurements are analyzed to detect patterns that repeat from one orbit to the next, but are displaced in location; the displacement provides a measure of the wind velocity. Pattern matching is achieved by re-sampling the CIPS data to a standard geographic grid with a horizontal resolution of 0.2° longitude × 0.05° latitude (~25 km2), and correlating patterns within geographic frames of size 24° longitude × 3.6° latitude. Such a frame size is arbitrarily chosen, but it covers a hierarchy of cloud structures including scales as large as several hundred kilometers. A relatively larger frame is required because after ~90 minutes, the time of one orbit, the smaller scale features are no longer conserved. Several thousand pairs, taken from 10-14 July 2007, are matched to derive the statistics. These pairs are mostly evenly distributed at longitudes and latitudes north of 70⁰N for each given day. The results suggest that the zonal velocity probability distribution during this 5-day period was peaked at around -40m/s with a 1-σ scatter of ~35m/s. The meridional velocity distribution peaked at 0 m/s with a 1-σ scatter of ~25m/s. These prevailing velocities can be determined with high precision because the corresponding patterns are shifted by at least half of the frame size from one orbit to the next. The CIPS cloud albedo on consecutive orbits is also examined for variations at fixed locations. The statistical results suggest that the mean cloud albedo within a given frame will most likely be weakened or strengthened by < 30% on consecutive orbits, although larger variations can occur with lower probability. Such a conclusion applies to both bright and dim clouds. This indicates that within 90 minutes the cloud brightness

  6. The Transfer Function Model (TFM) as a Tool for Simulating Gravity Wave Phenomena in the Mesosphere

    NASA Astrophysics Data System (ADS)

    Porter, H.; Mayr, H.; Moore, J.; Wilson, S.; Armaly, A.

    2008-12-01

    The Transfer Function Model (TFM) is semi-analytical and linear, and it is designed to describe the acoustic gravity waves (GW) propagating over the globe and from the ground to 600 km under the influence of vertical temperature variations. Wave interactions with the flow are not accounted for. With an expansion in terms of frequency-dependent spherical harmonics, the time consuming vertical integration of the conservation equations is reduced to computing the transfer function (TF). (The applied lower and upper boundary conditions assure that spurious wave reflections will not occur.) The TF describes the dynamical properties of the medium divorced from the complexities of the temporal and horizontal variations of the excitation source. Given the TF, the atmospheric response to a chosen source is then obtained in short order to simulate the GW propagating through the atmosphere over the globe. In the past, this model has been applied to study auroral processes, which produce distinct wave phenomena such as: (1) standing lamb modes that propagate horizontally in the viscous medium of the thermosphere, (2) waves generated in the auroral oval that experience geometric amplification propagating to the pole where constructive interference generates secondary waves that propagate equatorward, (3) ducted modes propagating through the middle atmosphere that leak back into the thermosphere, and (4) GWs reflected from the Earth's surface that reach the thermosphere in a narrow propagation cone. Well-defined spectral features characterize these wave modes in the TF to provide analytical understanding. We propose the TFM as a tool for simulating GW in the mesosphere and in particular the features observed in Polar Mesospheric Clouds (PMC). With present-day computers, it takes less than one hour to compute the TF, so that there is virtually no practical limitation on the source configurations that can be applied and tested in the lower atmosphere. And there is no limitation on

  7. Stratosphere/mesosphere coupling during the winter/summer transition at Davis, Antarctica

    NASA Astrophysics Data System (ADS)

    Lübken, Franz-Josef; Höffner, Josef; Viehl, Timo P.; Becker, Erich; Latteck, Ralph; Kaifler, Bernd; Morris, Ray J.

    2015-04-01

    The mobile scanning iron lidar of the Leibniz Institute of Atmospheric Physics in Kühlungsborn (IAP) was in operation at Davis, Antarctica, from December 15, 2010, until December 31, 2012. It measured iron densities, vertical winds, and temperatures in the iron layer, i. e. from approximately 80 to 100 km. The measurement principle is based on probing the Doppler broadened resonance line of iron atoms at 386 nm. The lidar can operate under daylight conditions. Typical values for temperature uncertainty, altitude and time resolution are 3-5 K, 1 km, and 1 hour, respectively. At Davis, the lidar has achieved at total of 2900 hours of temperature measurements which is presumably the largest nearly continuous data set in Antarctica. In this presentation we concentrate on the winter/summer transition in three consecutive years and compare with circulation changes in the stratosphere derived from MERRA (NASA's Modern-Era Retrospective analysis for Research and Applications). We also compare with the northern hemisphere (NH). We find that the thermal structure around the mesopause at Davis is closely coupled to the general circulation in the stratosphere, more precisely to the transition from winter to summer conditions. In contrast to theoretical expectations we occasionally find the mesopause significantly higher and colder(!) compared to the NH. The mesopause altitude changes by several kilometers throughout the summer season, which is significantly different from the summer in the northern hemispheric. Depending on altitude, temperatures can be warmer or colder compared to the NH summer. The Australian Antarctic Division has been operating a 55 MHz VHF radar at Davis since February 2003. We have studied the seasonal variation of polar mesosphere summer echoes (PMSE). PMSE are strong radar echoes related to ice particles and therefore require atmospheric temperatures lower than the frost point temperature. We note that (apart from low temperatures) more ingredients

  8. A semi-empirical model for mesospheric and stratospheric NOy produced by energetic particle precipitation

    NASA Astrophysics Data System (ADS)

    Funke, Bernd; López-Puertas, Manuel; Stiller, Gabriele P.; Versick, Stefan; von Clarmann, Thomas

    2016-07-01

    The MIPAS Fourier transform spectrometer on board Envisat has measured global distributions of the six principal reactive nitrogen (NOy) compounds (HNO3, NO2, NO, N2O5, ClONO2, and HNO4) during 2002-2012. These observations were used previously to detect regular polar winter descent of reactive nitrogen produced by energetic particle precipitation (EPP) down to the lower stratosphere, often called the EPP indirect effect. It has further been shown that the observed fraction of NOy produced by EPP (EPP-NOy) has a nearly linear relationship with the geomagnetic Ap index when taking into account the time lag introduced by transport. Here we exploit these results in a semi-empirical model for computation of EPP-modulated NOy densities and wintertime downward fluxes through stratospheric and mesospheric pressure levels. Since the Ap dependence of EPP-NOy is distorted during episodes of strong descent in Arctic winters associated with elevated stratopause events, a specific parameterization has been developed for these episodes. This model accurately reproduces the observations from MIPAS and is also consistent with estimates from other satellite instruments. Since stratospheric EPP-NOy depositions lead to changes in stratospheric ozone with possible implications for climate, the model presented here can be utilized in climate simulations without the need to incorporate many thermospheric and upper mesospheric processes. By employing historical geomagnetic indices, the model also allows for reconstruction of the EPP indirect effect since 1850. We found secular variations of solar cycle-averaged stratospheric EPP-NOy depositions on the order of 1 GM. In particular, we model a reduction of the EPP-NOy deposition rate during the last 3 decades, related to the coincident decline of geomagnetic activity that corresponds to 1.8 % of the NOy production rate by N2O oxidation. As the decline of the geomagnetic activity level is expected to continue in the coming decades, this is

  9. Mesospheric potassium layer observation by a frequency-tunable resonance scattering lidar system

    NASA Astrophysics Data System (ADS)

    Ejiri, Mitsumu K.; Nakamura, Takuji; Kawahara, Takuya D.; Abo, Makoto; Nishiyama, Takanori; Tsuda, Takuo T.

    The National Institute of Polar Research (NIPR) is leading a six year prioritized project of the Antarctic research observations since 2010. One of the sub-project is entitled "the global environmental change revealed through the Antarctic middle and upper atmosphere". Profiling dynamical parameters such as temperature and wind, as well as minor constituents is the key component of observations in this project, together with a long term observations using existent various instruments in Syowa, the Antarctic (69S, 39E). As a part of the sub-project, Rayleigh/Raman lidar was installed at Syowa Station in January, 2011 and has measured temperature profiles more than 3000 hours by February, 2014. In order to extend the height coverage to include mesosphere and lower thermosphere region, and also to extend the parameters observed, a new resonance scattering lidar system with tunable wavelengths is developed at NIPR in Tokyo (36N, 139E), Japan. The lidar transmitter is based on injection-seeded, pulsed alexandrite laser for 768-788 nm (fundamental wavelengths) and a second-harmonic generation (SHG) unit for 384-394 nm (second harmonic wavelengths). The laser wavelengths are tuned in to the resonance wavelengths by a wavemeter that is well calibrated using a wavelength-stabilized He-Ne laser. The new lidar has capabilities to measure density variations of minor constituents such as atomic iron (Fe, 386 nm), atomic potassium (K, 770 nm), calcium ion (Ca+, 393 nm), and aurorally excited nitrogen ion (N2+, 390-391 nm) and temperature profiles in the mesosphere and lower thermosphere (MLT) region using resonance scatter of K. This unique observation is expected to make important contribution to studies on the atmospheric vertical coupling process and the neutral and charged particle interaction. The resonance scattering lidar system is being developed at NIPR in Tokyo and conducting observations at the mid-latitude. The fundamental laser pulses are transmitted with 120-160 m

  10. Energy balance constraints on gravity wave induced eddy diffusion in the mesosphere and lower thermosphere

    NASA Technical Reports Server (NTRS)

    Strobel, D. F.; Apruzese, J. P.; Schoeberl, M. R.

    1985-01-01

    The constraints on turbulence improved by the mesospheric heat budget are reexamined, and the sufficiency of the theoretical evidence to support the hypothesis that the eddy Prandtl number is greater than one in the mesosphere is considered. The mesopause thermal structure is calculated with turbulent diffusion coefficients commonly used in chemical models and deduced from mean zonal wind deceleration. It is shown that extreme mesopause temperatures of less than 100 K are produced by the large net cooling. The results demonstrate the importance of the Prandtl number for mesospheric turbulence.

  11. 18-months of UV irradiance observations from the Solar Mesosphere Explorer

    NASA Technical Reports Server (NTRS)

    London, J.; Bjarnason, G. G.; Rottman, G. J.

    1984-01-01

    An instrument on the Solar Mesosphere Explorer has been making daily solar irradiance measurements in the 120-305 nm (UV) spectral interval since October 6, 1981. Calculations of the highest to lowest value of the irradiance within each solar rotation yield percent range values indicative of variations that are useful as input data for model calculations of stratosphere/mesosphere responses to short period solar variability, since solar radiation in the UV is largely responsible for the photochemical interactions and radiative heating of the stratosphere, mesosphere, and lower thermosphere.

  12. Simultaneous Observations fo Polar Stratospheric Clouds and HNO3 over Scandinavia in January, 1992

    NASA Technical Reports Server (NTRS)

    Massie, S. T.; Santee, M. L.; Read, W. G.; Grainger, R. G.; Lambert, A.; Mergenthaler, J. L.; Dye, J. E.; Baumbardner, D.; Randel, W. J.; Tabazadeh, A.; Tie, X.; Pan, L.; Figarol, F.; Wu, F.; Brasseur, G. P.

    1996-01-01

    Simultaneous observations of Polar Stratospheric Cloud aerosol extinction and HNO3 mixing ratios over Scandinavia are examined for January 9-10, 1992. Data measured by the Microwave Limb Sounder (MLS), Cryogenic Limb Array Etalon, Spectrometer (CLAES), and Improved Stratospheric and Mesospheric Sounder (ISAMA) experiments on the Upper Atmosphere Research Satellite (UARS) are examined at locations adjacent to parcel trajectory positions.

  13. The Polar Summer MLT Plasma Environment as Seen by the DROPPS Sounding Rockets

    NASA Technical Reports Server (NTRS)

    Assis, Michael P.; Goldberg, Richard A.; Webb, Phillip A.; Pesnell, William D.; Voss, H. D.

    2006-01-01

    During early July, 1999, the DROPPS (Distribution and Role of Particles in the Polar Summer Mesosphere) campaign launched two rocket payloads whose purpose was to study the polar summer MLT (mesosphere and lower thermosphere), particularly PMSEs (polar mesospheric summer echoes) and PMCs (polar mesospheric clouds). The rockets were launched from the Anderya Rocket Range in Norway the nights of the 5th and 14th of July. Both payloads included a front-mounted PID (Particle Impact Detector) consisting of charge and mass telescopes to measure aerosol and dust mass distributions. Ice particles of nanometer size are believed to be responsible for PMSEs through the process of electron scavenging. Evidence for this process is suggested, for example, by the presence of an electron "biteout" simultaneously measured by several instruments at an altitude of approx. 82 - 87km during the first DROPPS launch. This presentation will characterize similarities and differences between both flights as seen by the charge and mass telescopes, starting at launch until the loss of data on the downleg of each flight. Various stages of the flights will be considered in detail, such as the PMSE layer and the apogee at 117 km, as well as the calibration of the data before launch.

  14. The Polar Summer MLT Plasma Environment as seen by the DROPPS Sounding Rockets

    NASA Technical Reports Server (NTRS)

    Assis, Michael P.; Goldberg, Richard A.; Webb, Phillip; Pesnell, W. Dean; Voss, Henry D.

    2006-01-01

    During early July, 1999, the DROPPS (Distribution and Role of Particles in the Polar Summer Mesosphere) campaign launched two rocket payloads whose purpose was to study the polar summer MLT (mesosphere and lower thermosphere), particularly PMSEs (polar mesospheric summer echoes) and PMCs (polar mesospheric clouds). The rockets were launched from the And(\\o)ya Rocket Range in Norway the nights of the 5th and 14th of July. Both payloads included a front-mounted PID (Particle Impact Detector) consisting of charge and mass telescopes to measure aerosol and dust mass distributions. Ice particles of nanometer size are believed to be responsible for PMSEs through the process of electron scavenging. Evidence for this process is suggested, for example, by the presence of an electron "biteout" simultaneously measured by several instruments at an altitude of $\\sim$82-87 km during the first DROPPS launch. This presentation will characterize similarities and differences between both flights as seen by the charge and mass telescopes, starting at launch until the loss of data on the downleg of each flight. Various stages of the flights will be considered in detail, such as the PMSE layer and the apogee at 117 km, as well as the calibration of the data before launch.

  15. The Polar Summer MLT Plasma Environment as Seen by the DROPPS Sounding Rockets

    NASA Astrophysics Data System (ADS)

    Assis, M. P.; Goldberg, R. A.; Webb, P. A.; Pesnell, W. D.; Voss, H. D.

    2006-12-01

    During early July, 1999, the DROPPS (Distribution and Role of Particles in the Polar Summer Mesosphere) campaign launched two rocket payloads whose purpose was to study the polar summer MLT (mesosphere and lower thermosphere), particularly PMSEs (polar mesospheric summer echoes) and PMCs (polar mesospheric clouds). The rockets were launched from the Andøya Rocket Range in Norway the nights of the 5th and 14th of July. Both payloads included a front-mounted PID (Particle Impact Detector) consisting of charge and mass telescopes to measure aerosol and dust mass distributions. Ice particles of nanometer size are believed to be responsible for PMSEs through the process of electron scavenging. Evidence for this process is suggested, for example, by the presence of an electron "biteout" simultaneously measured by several instruments at an altitude of ~82-87 km during the first DROPPS launch. This presentation will characterize similarities and differences between both flights as seen by the charge and mass telescopes, starting at launch until the loss of data on the downleg of each flight. Various stages of the flights will be considered in detail, such as the PMSE layer and the apogee at 117 km, as well as the calibration of the data before launch.

  16. Observations of planetary waves in the mesosphere-lower thermosphere during stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Stray, N. H.; Orsolini, Y. J.; Espy, P. J.; Limpasuvan, V.; Hibbins, R. E.

    2015-05-01

    This study investigates the effect of stratospheric sudden warmings (SSWs) on planetary wave (PW) activity in the mesosphere-lower thermosphere (MLT). PW activity near 95 km is derived from meteor wind data using a chain of eight SuperDARN radars at high northern latitudes that span longitudes from 150° W to 25° E and latitudes from 51 to 66° N. Zonal wave number 1 and 2 components were extracted from the meridional wind for the years 2000-2008. The observed wintertime PW activity shows common features associated with the stratospheric wind reversals and the accompanying stratospheric warming events. Onset dates for seven SSW events accompanied by an elevated stratopause (ES) were identified during this time period using the Specified Dynamics Whole Atmosphere Community Climate Model (SD-WACCM). For the seven events, a significant enhancement in wave number 1 and 2 PW amplitudes near 95 km was found to occur after the wind reversed at 50 km, with amplitudes maximizing approximately 5 days after the onset of the wind reversal. This PW enhancement in the MLT after the event was confirmed using SD-WACCM. When all cases of polar cap wind reversals at 50 km were considered, a significant, albeit moderate, correlation of 0.4 was found between PW amplitudes near 95 km and westward polar-cap stratospheric winds at 50 km, with the maximum correlation occurring ∼ 3 days after the maximum westward wind. These results indicate that the enhancement of PW amplitudes near 95 km is a common feature of SSWs irrespective of the strength of the wind reversal.

  17. Mesosphere Dynamics with Gravity Wave Forcing. 2; Planetary Waves

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G.; Chan, K. L.; Porter, H. S.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    We present results from a non-linear, 3D, time dependent numerical spectral model (NSM) which extends from the ground up into the thermosphere and incorporates Hines' Doppler Spread Parameterization for small-scale gravity waves (GW). Our focal point is the mesosphere where wave interactions are playing a dominant role. We discuss planetary waves in the present paper and diurnal and semi-diurnal tides in the companion paper. Without external time dependent energy or momentum sources, planetary waves (PWs) are generated in the model for zonal wavenumbers 1 to 4, which have amplitudes in the mesosphere above 50 km as large as 30 m/s and periods between 2 and 50 days. The waves are generated primarily during solstice conditions, which indicates that the baroclinic instability (associated with the GW driven reversal in the latitudinal temperature gradient) is playing an important role. Results from a numerical experiment show that GWs are also involved directly in generating the PWs. For the zonal wavenumber m = 1, the predominant wave periods in summer are around 4 days and in winter between 6 and 10 days. For m = 2, the periods are in summer and close to 2.5 and 3.5 days respectively For m = 3, 4 the predominant wave periods are in both seasons close to two days. The latter waves have the characteristics of Rossby gravity waves with meridional winds at equatorial latitudes. A common feature of the PWs (m = 1 to 4) generated in summer and winter is that their vertical wavelengths throughout the mesosphere are large which indicates that the waves are not propagating freely but are generated throughout the region. Another common feature is that the PWs propagate preferentially westward in summer and eastward in winter, being launched from the westward and eastward zonal winds that prevail respectively in summer and winter altitudes below 80 km. During spring and fall, for m = 1 and 2 eastward propagating long period PWs are generated that are launched from the smaller

  18. Overview of the Temperature Response in the Mesosphere and Lower Thermosphere to Solar Activity

    NASA Technical Reports Server (NTRS)

    Beig, Gufran; Scheer, Juergen; Mlynczak, Martin G.; Keckhut, Philippe

    2008-01-01

    The natural variability in the terrestrial mesosphere needs to be known to correctly quantify global change. The response of the thermal structure to solar activity variations is an important factor. Some of the earlier studies highly overestimated the mesospheric solar response. Modeling of the mesospheric temperature response to solar activity has evolved in recent years, and measurement techniques as well as the amount of data have improved. Recent investigations revealed much smaller solar signatures and in some case no significant solar signal at all. However, not much effort has been made to synthesize the results available so far. This article presents an overview of the energy budget of the mesosphere and lower thermosphere (MLT) and an up-to-date status of solar response in temperature structure based on recently available observational data. An objective evaluation of the data sets is attempted and important factors of uncertainty are discussed.

  19. Mesospheric Odd Nitrogen Enhancements During Relativistic Electron Precipitation Events

    NASA Technical Reports Server (NTRS)

    Aikin, A. C.; Smith, H. J. P.

    1999-01-01

    The behavior of mesospheric odd nitrogen species during and following relativistic and diffuse auroral precipitation events is simulated, Below 75 km nitric oxide is enhanced in proportion to the ion pair production function associated with the electron precipitation and the length of the event. Nitrogen dioxide and nitric acid are also enhanced. At 65 km the percentage of odd nitrogen for N is 0.1%, HNO3 is 1.6%, NO2 is 15%, and NO is 83.3%. Between 75 and 85 km NO is depleted during particle events due to the faster destruction of NO by N relative to the production of NO by N reacting with O2. Recovery of NO depends on transport from the lower thermosphere, where NO is produced in abundant amounts during particle events.

  20. Cellular automaton modeling of mesospheric optical emissions: Sprites

    SciTech Connect

    Hayakawa, M.; Iudin, D. I.; Mareev, E. A.; Trakhtengerts, V. Y.

    2007-04-15

    This paper presents a new attempt to model two-dimensional mesospheric optical emissions named sprites with the use of a cellular automaton network. A large-scale model of sprites based on the phenomenological percolation-like probabilistic approach is developed to model streamer discharges in sprites. It is shown that a sprite is a self-affine structure rather than a simple fractal one, and that this self-affine structure is tightly connected with directed percolation phenomena. The system is found to evolve in the vicinity of the percolation threshold, which results in a wide variety of sprite characteristics even under similar initial conditions. The approach developed allows us to estimate a maximum size of the discharge pattern to be formed.

  1. Venus mesosphere and thermosphere. I - Heat budget and thermal structure

    NASA Astrophysics Data System (ADS)

    Dickinson, R. E.; Bougher, S. W.

    1986-01-01

    The calculation of a reasonable global average temperature structure is the first step in the simulation of the dynamics and observed characteristics of Venus's upper mesosphere and thermosphere. Various physical processes that influence Venus temperatures are examined, using updated inputs and new parameterizations. It is demonstrated, using a one-dimensional NLTE radiative transfer code, that temperatures observed during the Pioneer Venus mission can be reproduced using an O-CO2 collisional excitation rate coefficient of 4 x 10 to the -13th cu cm/s for strong 15-micron cooling, balanced by 9.5 percent-efficient EUV heating. Cooling by eddy mixing is at best a minor contribution to the total cooling required. Exospheric temperatures are calculated to vary by 60 K or less over a solar cycle, in rough agreement with observations. It is concluded that CO2 cooling effectively buffers against such solar perturbations, due to its nonlinear temperature dependence.

  2. Submillimeter mapping of mesospheric minor species on Venus with ALMA

    NASA Astrophysics Data System (ADS)

    Encrenaz, T.; Moreno, R.; Moullet, A.; Lellouch, E.; Fouchet, T.

    2015-08-01

    Millimeter and submillimeter heterodyne spectroscopy offers the possibility of probing the mesosphere of Venus and monitoring minor species and winds. ALMA presents a unique opportunity to map mesospheric species of Venus. During Cycle 0, we have observed Venus on November 14 and 15, 2011, using the compact configuration of ALMA. The diameter of Venus was 11″ and the illumination factor was about 90%. Maps of CO, SO, SO2 and HDO have been built from transitions recorded in the 335-347 GHz frequency range. A mean mesospheric thermal profile has been inferred from the analysis of the CO transition at the disk center, to be used in support of minor species retrieval. Maps of SO and SO2 abundance show significant local variations over the disk and contrast variations by as much as a factor 4. In the case of SO2, the spatial distribution appears more "patchy", i.e. shows short-scale structures apparently disconnected from day-side and latitudinal variations. For both molecules, significant changes occur over a timescale of one day. From the disk averaged spectrum of SO recorded on November 14 at 346.528 GHz, we find that the best fit is obtained with a cutoff in the SO vertical distribution at 88±2 km and a uniform mixing ratio of 8.0±2.0 ppb above this level. The SO2 map of November 14, derived from the weaker transition at 346.652 GHz, shows a clear maximum in the morning side at low latitudes, which is less visible in the map of November 15. We find that the best fit for SO2 is obtained for a cutoff in the vertical distribution at 88±3 km and a uniform mixing ratio of 12.0±3.5 ppb above this level. The HDO maps retrieved from the 335.395 GHz show some enhancement in the northern hemisphere, but less contrasted variations than for the sulfur species maps, with little change between November 14 and 15. Assuming a typical D/H ratio of 200 times the terrestrial value in the mesosphere of Venus, we find that the disk averaged HDO spectrum is best fitted with a

  3. The SMILES observations of mesospheric ozone during the solar eclipse

    NASA Astrophysics Data System (ADS)

    Imai, Koji; Shiotani, Masato; Suzuki, Makoto; Akiyoshi, Hideharu; Ebisawa, Ken; Takahashi, Kenshi; Yamashita, Yousuke; Imamura, Takashi

    Solar eclipse temporally reduces the amount of solar radiation, providing an opportunity to verify the mesospheric ozone photochemistry under a changing solar radiation. During the annular solar eclipse occurred on 15 January 2010, Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) successfully observed the temporal changes in ozone concentration between at 52 and 76 km. Analysis of the data with an atmospheric chemistry box model showed that, (i) the lower the altitude is, the closer to the normal nighttime average the concentration near the maximum eclipse obscuration becomes, and (ii) even if there were the SMILES observation points under similar degrees of obscuration, the concentrations measured at an altitude differed between the sunlight increasing and decreasing phases.

  4. Synthesis and characterization of drug loaded albumin mesospheres for intratumoral chemotherapy

    NASA Astrophysics Data System (ADS)

    Freeman, Shema Taian

    Conventional chemotherapy is problematic due to toxic complications. Intratumoral (IT) drug delivery, offers a new, less toxic, potentially more effective treatment concept. The objectives of this research encompassed (1) an investigation of the synthesis of BSA mesospheres (MS) employing genipin (GEN) as a novel crosslinking agent, (2) comparison with glutaraldehyde (GTA) crosslinked mesosphere, (3) a study of process parameters to define conditions for the synthesis of 1-10microm drug loaded mesospheres, and (4) investigation of the drug delivery properties of such mesospheres for IT chemotherapy. Smooth, spherical BSA-MS, crosslinked with glutaraldehyde and genipin, were prepared in a dry particle size range of 1microm to 10microm. It was shown that increasing dispersion stirring rate, crosslinking time and GEN/BSA ratio led to a decrease in particle size and a narrower particle distribution. It was also shown that increasing crosslinking time, GEN/BSA ratio, BSA concentrations, GEN concentration slowed enzymatic degradation. Post-loading and in situ drug loading methods were studied for the incorporation of cyclophosphamide and cisplatin into mesospheres. Maximum post loading of cisplatin was 3.2% (w/w) and 2.6% (w/w) with GEN and with GTA crosslinking. For cyclophosphamide 8.2% (w/w) and 7.1% (w/w) loading was achieved with GEN and GTA respectively. In situ drug loaded MS genipin and glutaraldehyde crosslinked mesospheres were also synthesized with 1.8% (w/w) cisplatin (using GEN) and 1.2% (w/w) (using GTA). Maximum loading of 13.3% (w/w) was achieved for cyclophosphamide in genipin crosslinked mesospheres. The cytotoxicity of in situ loaded genipin and glutaraldehyde crosslinked cisplatin mesospheres was evaluated using a murine Lewis lung model. Both genipin and glutaraldehyde crosslinked BSA-cisplatin mesospheres proved to be cytotoxic during a 48 hour test. Ultimately a standard set of processing parameters (BSA concentration, CAB concentration, GEN

  5. A review of mesospheric and lower thermosphere models

    NASA Astrophysics Data System (ADS)

    Portnyagin, Yuri

    2006-01-01

    The empirical mesosphere/lower thermosphere (MLT) models, in particular Fleming et al. [Fleming, E.L., Chandra, S., Schoeberl, M.R., Barnett, J.J. Monthly mean global climatology of temperature, wind, geopotential height and pressure for 0-120 km. NASA Technical Memorandum 100697, 1988; Fleming, E.L., Chandra, S., Barnett, J.J., Corney, M. Zonal mean temperature, pressure, zonal wind and geopotential height as function of latitude. Adv. Space Res., 10 (12), 11-59, 1990.], HWM-93 [Hedin, A.E., Fleming, E.L., Manson, A.H., Schmidlin, F.J., Avery, S.K., Clark, R.R., Franke, S.J., Fraser, G.J., Tsuda, T., Vial, F., Vincent, R.A. Empirical wind model for the middle and lower atmosphere. J. Atmos.Terr. Phys., 58, 1421-1447, 1996] and GEWM [Portnyagin, Yu.I, Solovjova, T., Merzlyakov, E., et al., Mesosphere/lower thermosphere prevailing wind model. Adv. Space Res., 34, 1755-1762, 2004] models, are compared. The main reasons of the differences between the models are discussed. These reasons are mainly connected with the differences between the used ground- and space-based datasets, including the systematic biases between the ground-based and space-based measurements, and with the different methods of the data assimilation. The effects of year-to-year wind variations and the longitudinal prevailing wind variability, as well as the effects of non-migrating tides in construction of the climatic empirical models is not so strong. The recommendation to construct a new and updated CIRA wind model for the MLT region has been followed.

  6. Optical remote sensing of the mesosphere, thermosphere, and ionosphere

    NASA Astrophysics Data System (ADS)

    McCoy, Robert P.

    1995-01-01

    Over the next five years the Naval Research Laboratory (NRL) will fly a series of ultraviolet satellite instrument packages to measure vertical profiles of atmospheric airglow emission. The objective of this program is to test new techniques for optical remote sensing of the mesosphere, thermosphere, and ionosphere using limb scanning spectrographs. Emphasis will be placed on day- and night-remote sensing of the F-region through measurement of profiles of airglow emission from the O+ ion. Other objectives include remote sensing of vertical profiles of neutral density, minor species and temperature. These observations will be used to study the composition, photochemistry, thermodynamics, and couplings between atmospheric regions. A phased approach will be used which provides for: (1) comprehensive multi-parameter measurements; (2) high spectral resolution studies; and (3) long-term operational observations from DoD weather satellites. The first of these payloads is the multi- sensor experiment called the remote atmospheric & ionospheric detection (RAIDS). RAIDS, a collaboration between NRL and The Aerospace Corporation, contains two spectrographs, three scanning grating spectrometers, and three photometers. Space flight for RAIDS will be provided by the Air Force Space Test Program (STP). The phase 2 component is the high resolution airglow/aurora spectroscopy (HIRAAS) experiment, a collaboration between NRL and the Naval Postgraduate School. HIRAAS will fly aboard the STP ARGOS Satellite in early 1996. The third phase of this program involves flight of a series of five limb scanning instruments called the special sensor ultraviolet limb imager (SSULI) aboard Defense Meteorological Satellite Program weather satellites in the last quarter of this decade. The long- term observations from these satellite experiments will provide a comprehensive database of mesospheric, thermospheric, and ionospheric density profiles from which to search for the effects of global change.

  7. A multidiagnostic investigation of the mesospheric bore phenomenon

    NASA Astrophysics Data System (ADS)

    Smith, Steven M.; Taylor, Michael J.; Swenson, Gary R.; She, Chiao-Yao; Hocking, Wayne; Baumgardner, Jeffrey; Mendillo, Michael

    2003-02-01

    Imaging measurements of a bright wave event in the nighttime mesosphere were made on 14 November 1999 at two sites separated by over 500 km in the southwestern United States. The event was characterized by a sharp onset of a series of extensive wavefronts that propagated across the entire sky. The waves were easily visible to the naked eye, and the entire event was observed for at least 5? hours. The event was observed using three wide-angle imaging systems located at the Boston University field station at McDonald Observatory (MDO), Fort Davis, Texas, and the Starfire Optical Range (SOR), Albuquerque, New Mexico. The spaced imaging measurements provided a unique opportunity to estimate the physical extent and time history of the disturbance. Simultaneous radar neutral wind measurements in the 82 to 98 km altitude region were also made at the SOR which indicated that a strong vertical wind shear of 19.5 ms-1km-1 occurred between 80 and 95 km just prior to the appearance of the disturbance. Simultaneous lidar temperature and density measurements made at Fort Collins, Colorado, ˜1100 km north of MDO, show the presence of a large (˜50 K) temperature inversion layer at the time of the wave event. The observations indicated that the event was most probably due to an undular mesospheric bore, a relatively uncommon disturbance which has only recently been reported [, 1995a]. Evidence is also shown to suggest that a large east-west tropospheric frontal system lying over the northern United States was the origin of the disturbance.

  8. Trends and solar cycle effects in mesospheric ice clouds

    NASA Astrophysics Data System (ADS)

    Lübken, Franz-Josef; Berger, Uwe; Fiedler, Jens; Baumgarten, Gerd; Gerding, Michael

    Lidar observations of mesospheric ice layers (noctilucent clouds, NLC) are now available since 12 years which allows to study solar cycle effects on NLC parameters such as altitudes, bright-ness, and occurrence rates. We present observations from our lidar stations in Kuehlungsborn (54N) and ALOMAR (69N). Different from general expectations the mean layer characteris-tics at ALOMAR do not show a persistent anti-correlation with solar cycle. Although a nice anti-correlation of Ly-alpha and occurrence rates is detected in the first half of the solar cycle, occurrence rates decreased with decreasing solar activity thereafter. Interestingly, in summer 2009 record high NLC parameters were detected as expected in solar minimum conditions. The morphology of NLC suggests that other processes except solar radiation may affect NLC. We have recently applied our LIMA model to study in detail the solar cycle effects on tempera-tures and water vapor concentration the middle atmosphere and its subsequent influence on mesospheric ice clouds. Furthermore, lower atmosphere effects are implicitly included because LIMA nudges to the conditions in the troposphere and lower stratosphere. We compare LIMA results regarding solar cycle effects on temperatures and ice layers with observations at ALO-MAR as well as satellite borne measurements. We will also present LIMA results regarding the latitude variation of solar cycle and trends, including a comparison of northern and southern hemisphere. We have adapted the observation conditions from SBUV (wavelength and scatter-ing angle) in LIMA for a detailed comparison with long term observations of ice clouds from satellites.

  9. Variabilities of low latitude mesospheric and E region echoes: linked to common sources?

    NASA Astrophysics Data System (ADS)

    Dharmalingam, Selvaraj; Patra, Amit; Sathishkumar, Sundararaman; Narayana Rao, D.

    2016-07-01

    Variability in dynamics of the mesospheric and E region echoes have been studied in isolation. Both echoing phenomena are directly or indirectly coupled with each other through neutral dynamics. This is especially so for the low-latitudes outside the equatorial electrojet belt, where E region plasma irregularities causing radar echoes are governed by neutral dynamics, such as tides and gravity waves. Although these regions are close to each other, no effort has been made yet to understand the dynamical coupling processes manifesting the observed variabilities in the two echoing phenomena. To investigate linkage between the two phenomena, if any, we conducted systematic observations of low latitude mesospheric and E region echoes during 2011-2012 using the Gadanki MST radar and used these in conjunction with SABER temperature, MF radar wind, and sporadic E observations. Both echoes are found to occur in the height regions where temperature observations show negative gradients. Mesospheric echoes are collocated with temperature gradient associated with mesospheric temperature inversion while the E region echoes are collocated with negative temperature gradient close to the mesopause. Observations have revealed a common signature of semi-annual variations in the occurrence of both mesospheric and ionospheric E-region - occurrences peak in the equinoxes. The E region echoes have an additional peak occurring in the summer and this occurrence is well correlated with the enhancement in the diurnal tidal amplitude. We surmise that the enhancement in the diurnal tidal amplitude is linked with non-migrating tide of tropospheric weather phenomena in summer. Intriguingly, mesospheric echoing layers display descending pattern quite similar to the E region echoes and sporadic E layer, which have been used to invoke tidal dynamics in manifesting similar morphology in both mesospheric and E region echoes. These results will be presented and the role of tidal dynamics on the

  10. Long-term changes in the mesosphere calculated by a two-dimensional model

    NASA Astrophysics Data System (ADS)

    Gruzdev, Aleksandr N.; Brasseur, Guy P.

    2005-02-01

    We have used the interactive two-dimensional model SOCRATES to investigate the thermal and the chemical response of the mesosphere to the changes in greenhouse gas concentrations observed in the past 50 years (CO2, CH4, water vapor, N2O, CFCs), and to specified changes in gravity wave drag and diffusion in the upper mesosphere. When considering the observed increase in the abundances of greenhouse gases for the past 50 years, a cooling of 3-7 K is calculated in the mesopause region together with a cooling of 4-6 K in the middle mesosphere. Changes in the meridional circulation of the mesosphere damp the pure radiative thermal effect of the greenhouse gases. The largest cooling in the winter upper mesosphere-mesopause region occurs when the observed increase in concentrations of greenhouse gases and the strengthening of the gravity wave drag and diffusion are considered simultaneously. Depending on the adopted strengthening of the gravity wave drag and diffusion, a cooling varying from typically 6-10 K to 10-20 K over the past 50 years is predicted in the extratropical upper mesosphere during wintertime. In summer, however, consistently with observations, the thermal response calculated by the model is insignificant in the vicinity of the mesopause. Although the calculated cooling of the winter mesopause is still less than suggested by some observations, these results lead to the conclusion that the increase in the abundances of greenhouse gases alone may not entirely explain the observed temperature trends in the mesosphere. Long-term changes in the dynamics of the middle atmosphere (and the troposphere), including changes in gravity wave activity may have contributed significantly to the observed long-term changes in thermal structure and chemical composition of the mesosphere.

  11. Identification of water-soluble polar organics in air and vehicular emitted particulate matter using ultrahigh resolution mass spectrometry and Capillary electrophoresis - mass spectrometry.

    NASA Astrophysics Data System (ADS)

    Schmitt-Kopplin, P.; Yassine, M.; Gebefugi, I.; Hertkorn, N.; Dabek-Zlotorzynska, E.

    2009-04-01

    The effects of aerosols on human health, atmospheric chemistry, and climate are among the central topics in current environmental health research. Detailed and accurate measurements of the chemical composition of air particulate matter (PM) represent a challenging analytical task. Minute sample amounts are usually composed of several main constituents and hundreds of minor and trace constituents. Moreover, the composition of individual particles can be fairly uniform or very different (internally or externally mixed aerosols), depending on their origin and atmospheric aging processes (coagulation, condensation / evaporation, chemical reaction). The aim of the presentation was the characterization of the organic matter (OM) fraction of environmental aerosols which is not accessible by GC-methods, either because of their high molecular weight, their polarity or due to thermal instability. We also describe the main chemical characteristics of complexe oligomeric organic fraction extracted from different aerosols collected in urban and rural area in Germany and Canada. Mass spectrometry (MS) became an essential tool used by many prominent leaders of the biological research community and the importance of MS to the future of biological research is now clearly evident as in the fields of Proteomics and Metabolomics. Especially Fourier Transform Ion Cyclotron Mass Spectrometry (ICR-FT/MS) is an ultrahigh resolution MS that allows new approach in the analysis of complex mixtures. The mass resolution (< 200 ppb) allowed assigning the elemental composition (C, H, O, N, S…) to each of the obtained mass peaks and thus already a description of the mixture in terms of molecular composition. This possibility is used by the authors together with a high resolution separation method of charged compounds: capillary electrophoresis. A CE-ESI-MS method using an ammonium acetate based background electrolyte (pH 4.7) was developed for the determination of isomeric benzoic acids in

  12. Charged meteoric smoke as ice nuclei in the mesosphere: Part 1—A review of basic concepts

    NASA Astrophysics Data System (ADS)

    Gumbel, J.; Megner, L.

    2009-08-01

    The role of meteoric smoke as condensation nuclei for mesospheric ice has recently been challenged by model simulations on the global transport of meteoric material. At the same time a considerable fraction of smoke particles is charged in the mesosphere. This has significant effects on nucleation processes as it can remove the Kelvin barrier. We suggest that in particular nucleation on negatively charged smoke is likely to be a dominant mechanism for mesospheric ice formation. This is in contrast to nucleation on positive ion clusters as the latter is largely hampered by efficient ion/electron recombination. Surprisingly, the large potential of nucleation on charged smoke has so far not been considered in mesospheric ice models. A challenging question concerns the fraction of mesospheric smoke that is actually charged. An improved understanding of mesospheric charging and nucleation will require laboratory experiments on nuclei in the transition regime between molecular and particulate sizes.

  13. All Aboard! The Polar Express Is Traveling to Science--Understanding the States of Matter While Differentiating Instruction for Young Learners

    ERIC Educational Resources Information Center

    Vowell, Julie; Phillips, Marianne

    2015-01-01

    This standards-based science lesson introduces young learners to scientific inquiry and critical thinking by using activities to demonstrate three phases of matter (solid, liquid, and gas). By learning about the states of matter through a 5E instructional approach, students are encouraged to observe changes in the states of matter and to discuss…

  14. Wave-coupling from the troposphere to the mesosphere and thermosphere observed by the Optical Mesosphere Thermosphere Imagers (OMTIs)

    NASA Astrophysics Data System (ADS)

    Shiokawa, Kazuo; Otsuka, Yuichi; Takeo, Daiki; Fujinami, Hatsuki

    2016-07-01

    The airglow emissions from the mesopause region and the thermosphere are very useful to monitor dynamical variations of the neutral and plasma atmosphere in the upper atmosphere. The Optical Mesosphere Thermosphere Imagers (OMTIs) measure two-dimensional pattern, Doppler wind, and temperature through airglow emissions from oxygen (wavelength: 557.7 nm) and OH (near infrared band) in the mesopause region (80-100 km) and from oxygen (630.0 nm) in the thermosphere/ionosphere (200-300 km) at various locations in the world. Station information and quick look plots are available at http://stdb2.stelab.nagoya-u.ac.jp/omti/. In this presentation we show recent observations by OMTIs for the vertical coupling of atmospheric gravity waves from the troposphere to the mesopause region and to the thermosphere/ionosphere.

  15. Observations of the global structure of the stratosphere and mesosphere with sounding rockets and with remote sensing techniques from satellites

    NASA Technical Reports Server (NTRS)

    Heath, D. F.; Hilsenrath, E.; Krueger, A. J.; Nordberg, W.; Prabhakara, C.; Theon, J. S.

    1972-01-01

    Brief descriptions are given of the techniques involved in determining the global structure of the mesosphere and stratosphere based on sounding rocket observations and satellite remotely sensed measurements.

  16. Jupiter's Mesospheric Structure and Shape From Occultation of SAO 92746 (HIP 9369)

    NASA Astrophysics Data System (ADS)

    Hubbard, W. B.; Hill, R.; Rieke, M. J.; Drossart, P.; Roques, F.; Sicardy, B.; Widemann, T.; Doyon, R.; Nadeau, D.; Marley, M.

    2000-10-01

    The magnitude-7 star was occulted by Jupiter's high northern atmosphere on 10 October 1999. We report results from high-quality observations obtained at VLT (Chile), Kitt Peak and Catalina Station (Arizona), and Mt. Megantic (Canada). Our observations cover a jovian latitude range from 55 deg N to 73 deg N, and, when combined with data sets from stellar occultations in 1971 and 1989, with Voyager and Galileo Probe data, and with independent astrometry, enable us to investigate the overall oblateness of the jovian mesosphere at pressures of ~ 1 μ bar. Our high-jovian-latitude data sets probe a portion of the jovian atmosphere that may be subjected to auroral heating -- we compare our observed lightcurves with lightcurves predicted for auroral temperature-pressure profiles. For the Galileo Probe temperature (T) vs. pressure (P) profile, applicable to low latitudes, a single-parameter fit to a stellar occultation lightcurve yields an effective refractivity scale height (H) of 24 km. If this same T-P profile is applied to high latitudes, the effective H is about 21 km. With auroral heating, the inferred H increases to about 28 km. There is considerable scatter in the H values obtained from the 1999 occultation data, but some indication of the higher H values consistent with auroral heating. The oblateness e for the jovian atmosphere that we infer from the data sets lies between the dynamical oblateness e=0.06493 of Lindal et al. (JGR 86, 8721-8727, 1981), and the value derived from the 1971 β Sco occultation by Hubbard and Van Flandern, e=0.060 +/- 0.001 (AJ 77, 65-74, 1972). Thus, there is evidence that the polar jovian atmosphere at microbar pressures is ~ 100 km farther from the center of mass than would be the case for a barotropic planet in hydrostatic equilibrium. Supported in part by NASA Planetary Astronomy Program.

  17. Mesospheric temperature soundings with the new, daylight-capable IAP RMR lidar

    NASA Astrophysics Data System (ADS)

    Gerding, Michael; Kopp, Maren; Höffner, Josef; Baumgarten, Kathrin; Lübken, Franz-Josef

    2016-08-01

    Temperature measurements by lidar are an important tool for the understanding of the mean state of the atmosphere as well as the propagation of gravity waves and thermal tides. Though, mesospheric lidar soundings are often limited to nighttime conditions (e.g., solar zenith angle > 96°) due to the low signal-to-noise ratio during the day. By this, examination of long-period gravity waves and tides is inhibited, as well as soundings in summer at polar latitudes. We developed a new daylight-capable Rayleigh-Mie-Raman (RMR) lidar at our site in Kühlungsborn, Germany (54° N, 12° E), that is in routine operation since 2010 for temperature soundings up to 90 km or ˜ 75 km (night or day) and soundings of noctilucent clouds. Here we describe the setup of the system with special emphasis on the daylight suppression methods like spatial and spectral filtering. The small bandwidth of the Fabry-Pérot etalons for spectral filtering of the received signal induces an altitude-dependent transmission of the detector. As a result, the signal is no longer proportional to the air density and the hydrostatic integration of the profile results in systematic temperature errors of up to 4 K. We demonstrate a correction method and the validity of correction by comparison with data obtained by our co-located, nighttime-only RMR lidar where no etalon is installed. As a further example a time series of temperature profiles between 20 and 80 km is presented for day and night of 9-10 March 2014. Together with the other data of March 2014 these profiles are used to calculate tidal amplitudes. It is found that tidal amplitudes vary between ˜ 1 and 5 K depending on altitude.

  18. CHARACTERIZING THE TRANSFORMATION AND METABOLISM OF ANTHROPOGENIC ORGANIC MATTER IN ESTUARIES USING INTACT POLAR LIPIDS: A BIOMARKER APPROACH TO ECOSYSTEM HEALTH ASSESSMENT

    EPA Science Inventory

    Because polar lipids are critical structural components of all planktonic cells, it is expected that anthropogenic stressors will be found to alter substantively the relative proportions and types of polar lipids produced by various species in the two ecosystems. In additio...

  19. MTeX: The Mesosphere-Lower Thermosphere Turbulence Experiment

    NASA Astrophysics Data System (ADS)

    Collins, R. L.; Triplett, C. C.; Barjatya, A.; Lehmacher, G. A.; Fritts, D. C.; Luebken, F. J.; Strelnikov, B.; Nicolls, M. J.

    2015-12-01

    The Mesosphere-Lower Thermosphere Turbulence Experiment (MTeX) is a rocket-based experiment that was conducted on the night of the 25-26 January 2015 at Poker Flat Research Range (PFRR), Chatanika, Alaska (65°N, 147°W). The experiment required two key elements: the ability to measure turbulence in well-defined meteorological conditions and the ability to measure fluctuations in the atmosphere at sub-meter scales. Modern lidar (or laser radar) systems provided the first element. Rocket-borne ionization gauges and ionization probes provided the second element. We used the established rocket launching and lidar facilities at PFRR to study this turbulence. The specific weather condition we required to frame our turbulence measurement was a Mesospheric Inversion Layer. MILs are a signature of large-scale planetary wave breaking in the upper atmosphere, where a region with a temperature inversion lies below a region with an adiabatic lapse rate. The region with the inversion allows small-scale waves to become unstable, break, and generate turbulence. The region with the adiabatic lapse rate is indicative of a well-mixed layer and the presence of turbulence. The Rayleigh lidar observations began at 18:37 25 January local time. By 20:30 we had acquired sufficient lidar signal to detect a MIL between 80-85 km. The first MTeX rocket was launched at 00:13 and the second one at 00:46. The lidar temperature soundings show that the atmosphere was disturbed with temperatures in the stratosphere being cooler than expected from climatology with no clear stratopause. Our preliminary analysis of the rocket measurements shows spectral characteristics typical of layers of strong turbulence. Measurements were made both on the upleg and downleg of each rocket flight. In this presentation we present the technical details of the rocket flight, key data from the flight, and show how that data from different instruments is combined to characterize the waves and turbulence present during

  20. Infrared radiation in the mesosphere and lower thermosphere: energetic effects and coupling with lower atmosphere

    NASA Astrophysics Data System (ADS)

    Feofilov, Artem; Kutepov, Alexander; Rezac, Ladislav

    2013-04-01

    The translational degrees of freedom of atmospheric molecular and atomic gaseous compounds represent the heat reservoir. This reservoir obtains or loses energy due to a number of sources and sinks, among them heating and cooling related to various types of mass motions, redistribution of energy released in the course of various photochemical reactions (the translational energy, the chemical energy and the nascent electronic, vibration and rotational energy of the reaction products), and absorption and emission of the infrared (IR) radiation. In the latter case, one deals with interaction between matter and the IR radiative field, which, for the case of the mesosphere/lower thermosphere (MLT), includes the atmospheric radiation formed in these layers, the upwelling radiation from the ground and lower atmosphere, and, during daytime, the IR solar radiation. In this talk, we address the energetic effects of IR radiation in the MLT and its radiative coupling with lower atmosphere by analyzing the interaction between IR radiation and matter. In the MLT, this interaction is strongly affected by the situation when vibrational (and in its upper part also rotational) excitation of the molecules does not obey Boltzmann's law with the local kinetic temperature. As a result, the IR radiation emitted in these layers does not reflect the thermal state of matter. This situation is referred to as the breakdown of local thermodynamic equilibrium (LTE) for the vibrational (or rotational-vibrational) degrees of freedom. Detailed treatment of non-LTE plays a crucial role for estimating thermal effects of the IR radiation as well as for the diagnostics of space-based IR observations. We discuss the peculiarities of the non-LTE radiation formation in the IR bands of CO2, O3, and H2O molecules, estimate radiative cooling/heating rates for typical atmospheric scenarios, and analyze sensitivity of the MLT radiative energy balance to various mechanisms of populating/depopulating molecular

  1. Modeling of long-term change in the mesosphere: Radiative and dynamical mechanisms

    NASA Astrophysics Data System (ADS)

    Gruzdev, A.; Brasseur, G.

    We have used the interactive two-dimensional model, SOCRATES, to investigate the response of the thermal structure and chemical composition of the mesosphere to the changes in greenhouse gas concentrations (CO2, CH4, water vapor, N2O, CFCs) observed for the past 50 years, and the response to specified changes in gravity wave drag and diffusion in the upper mesosphere. When considering the observed increase in the abundances of greenhouse gases for the past 50 years, a cooling of 3-7 K has been calculated in the mesopause region together with a cooling of 4-6 K in the middle mesosphere. These effects are significantly lower than the cooling suggested by observations. Increased gravity wave drag and diffusion in the upper mesosphere results in a calculated cooling of several Kelvin in this region of the atmosphere. Larger cooling occurs in the winter upper mesosphere-mesopause region when the observed increase in concentrations of greenhouse gases and the strengthening of the gravity wave drag and diffusion are considered simultaneously in the model. In summer, consistently with observations, a thermal effect in this layer is insignificant, while a significant cooling (˜ 10 K and more) occurs in the middle mesosphere. Depending on the adopted strengthening of the gravity wave drag and diffusion, the cooling in the northern hemisphere extratropical mesopause layer in winter varies from 6-10 K to 10-20 K. The cooling of the mesopause is associated with the significant predicted increase in abundances of methane and water vapor in the upper mesosphere, and with the increase in the divergence of the vertical diffusive flux of heat (downward) in this region, due to enhanced diffusive transport of heat and species in the region of intense gravity wave breaking. Although the calculated cooling of the winter mesopause is still less than suggested by observations, these results lead to the conclusion that the increase in abundances of greenhouse gases alone could not explain

  2. In-flight calibration of mesospheric rocket plasma probes

    SciTech Connect

    Havnes, Ove; Hartquist, Thomas W.; Kassa, Meseret; Morfill, Gregor E.

    2011-07-15

    Many effects and factors can influence the efficiency of a rocket plasma probe. These include payload charging, solar illumination, rocket payload orientation and rotation, and dust impact induced secondary charge production. As a consequence, considerable uncertainties can arise in the determination of the effective cross sections of plasma probes and measured electron and ion densities. We present a new method for calibrating mesospheric rocket plasma probes and obtaining reliable measurements of plasma densities. This method can be used if a payload also carries a probe for measuring the dust charge density. It is based on that a dust probe's effective cross section for measuring the charged component of dust normally is nearly equal to its geometric cross section, and it involves the comparison of variations in the dust charge density measured with the dust detector to the corresponding current variations measured with the electron and/or ion probes. In cases in which the dust charge density is significantly smaller than the electron density, the relation between plasma and dust charge density variations can be simplified and used to infer the effective cross sections of the plasma probes. We illustrate the utility of the method by analysing the data from a specific rocket flight of a payload containing both dust and electron probes.

  3. Silicon chemistry in the mesosphere and lower thermosphere

    NASA Astrophysics Data System (ADS)

    Plane, John; Gómez-Martín, Juan Carlos; Feng, Wuhu; Janches, Diego

    2016-04-01

    Silicon is one of the most abundant elements in cosmic dust, and meteoric ablation injects a significant amount of Si into the atmosphere above 80 km. In this study, a new model for silicon chemistry in the mesosphere/lower thermosphere is described, based on recent laboratory kinetic studies of Si, SiO, SiO2 and Si+. Electronic structure calculations and statistical rate theory are used to show that the likely fate of SiO2 is a 2-step hydration to silicylic acid (Si(OH)4), which then polymerizes with metal oxides and hydroxides to form meteoric smoke particles. This chemistry is then incorporated into a whole atmosphere chemistry-climate model. The vertical profiles of Si+ and the Si+/Fe+ ratio are shown to be in good agreement with rocket-borne mass spectrometric measurements between 90 and 110 km. Si+ has consistently been observed to be the major meteoric ion around 110 km; this implies that the relative injection rate of Si from meteoric ablation, compared to metals such as Fe and Mg, is significantly larger than expected based on their relative chondritic abundances. Finally, the global abundances of SiO and Si(OH)4 show clear evidence of the seasonal meteoric input function, which is much less pronounced in the case of other meteoric species.

  4. In-flight calibration of mesospheric rocket plasma probes.

    PubMed

    Havnes, Ove; Hartquist, Thomas W; Kassa, Meseret; Morfill, Gregor E

    2011-07-01

    Many effects and factors can influence the efficiency of a rocket plasma probe. These include payload charging, solar illumination, rocket payload orientation and rotation, and dust impact induced secondary charge production. As a consequence, considerable uncertainties can arise in the determination of the effective cross sections of plasma probes and measured electron and ion densities. We present a new method for calibrating mesospheric rocket plasma probes and obtaining reliable measurements of plasma densities. This method can be used if a payload also carries a probe for measuring the dust charge density. It is based on that a dust probe's effective cross section for measuring the charged component of dust normally is nearly equal to its geometric cross section, and it involves the comparison of variations in the dust charge density measured with the dust detector to the corresponding current variations measured with the electron and/or ion probes. In cases in which the dust charge density is significantly smaller than the electron density, the relation between plasma and dust charge density variations can be simplified and used to infer the effective cross sections of the plasma probes. We illustrate the utility of the method by analysing the data from a specific rocket flight of a payload containing both dust and electron probes. PMID:21806207

  5. Density and pressure variability in the mesosphere and thermosphere

    NASA Technical Reports Server (NTRS)

    Davis, T. M.

    1986-01-01

    In an effort to isolate the essential physics of the mesosphere and the thermosphere, a steady one-dimensional density and pressure model has been developed in support of related NASA activities, i.e., projects such as the AOTV and the Space Station. The model incorporates a zeroth order basic state including both the three-dimensional wind field and its associated shear structure, etc. A first order wave field is also incorporated in period bands ranging from about one second to one day. Both basic state and perturbation quantities satsify the combined constraints of mass, linear momentum and energy conservation on the midlatitude beta plane. A numerical (iterative) technique is used to solve for the vertical wind which is coupled to the density and pressure fields. The temperature structure from 1 to 1000 km and the lower boundary conditions are specified using the U.S. Standard Atmosphere 1976. Vertical winds are initialized at the top of the Planetary Boundary Layer using Ekman pumping values over flat terrain. The model also allows for the generation of waves during the geostrophic adjustment process and incorporates wave nonlinearity effects.

  6. Silicon chemistry in the mesosphere and lower thermosphere

    NASA Astrophysics Data System (ADS)

    Plane, John M. C.; Gómez-Martín, Juan Carlos; Feng, Wuhu; Janches, Diego

    2016-04-01

    Silicon is one of the most abundant elements in cosmic dust, and meteoric ablation injects a significant amount of Si into the atmosphere above 80 km. In this study, a new model for silicon chemistry in the mesosphere/lower thermosphere is described, based on recent laboratory kinetic studies of Si, SiO, SiO2, and Si+. Electronic structure calculations and statistical rate theory are used to show that the likely fate of SiO2 is a two-step hydration to silicic acid (Si(OH)4), which then polymerizes with metal oxides and hydroxides to form meteoric smoke particles. This chemistry is then incorporated into a whole atmosphere chemistry-climate model. The vertical profiles of Si+ and the Si+/Fe+ ratio are shown to be in good agreement with rocket-borne mass spectrometric measurements between 90 and 110 km. Si+ has consistently been observed to be the major meteoric ion around 110 km; this implies that the relative injection rate of Si from meteoric ablation, compared to metals such as Fe and Mg, is significantly larger than expected based on their relative chondritic abundances. Finally, the global abundances of SiO and Si(OH)4 show clear evidence of the seasonal meteoric input function, which is much less pronounced in the case of other meteoric species.

  7. Development of Mesospheric Sodium Laser Beacon for Atmospheric Adaptive Optics

    NASA Technical Reports Server (NTRS)

    Jeys, T. H.

    1992-01-01

    A solid-state source of long pulse length, sodium-resonance radiation was developed for the purpose of generating an artificial star in the earth's mesospheric sodium layer. This radiation is generated by sum-frequency mixing the output of a 1.064 micron Nd:YAG laser with the output of a 1.319-micron Nd:YAG laser. By operating these lasers at wavelengths very close to the peak of their tuning curves, it is possible to match the wavelength of the sum-frequency radiation to that of the sodium D2 adsorption wavelength. Two pulsed laser systems were constructed, one producing as much as 0.6 J of sodium resonance radiation at a 10-Hz repetition rate and another producing as much as 24 mJ at a 840-Hz repetition rate. In both laser systems, the 1.06-micron and 1.32-micron Nd:YAG lasers are configured as mode-locked master oscillators followed by power amplifiers. Other aspects of this project are presented.

  8. In situ observations of small scale neutral and plasma dynamics in the mesosphere/lower thermosphere at 79°N

    NASA Astrophysics Data System (ADS)

    Strelnikov, B.; Rapp, M.; Blix, T. A.; Engler, N.; Höffner, J.; Lautenbach, J.; Lübken, F.-J.; Smiley, B.; Friedrich, M.

    2006-01-01

    From June 29 to July 6 2003, the German-Norwegian ROMA-SvalRak campaign (ROMA = Rocket borne Observations in the Middle Atmosphere) took place at the SvalRak rocket range, Ny-Ålesund (78.9°N, 11.9°E; Spitzbergen). The main scientific aim of this campaign was to study polar mesosphere summer echoes (PMSE) and mesospheric turbulence. During this campaign a total of three instrumented sounding rockets was launched. In addition, ground based observations with a VHF radar and a potassium lidar at Longyearbyen complemented the in situ measurements. All three sounding rockets were equipped with the CONE (COmbined sensor for Neutrals and Electrons) instrument to measure small scale structure of neutral air and electron density, and neutral temperature. The PIP (positive ion probe) instrument was used to measure small scale structure of the positive ion density. Furthermore, two cold plasma probes were flown to measure electron temperature, and a particle detector was employed to detect signatures of charged aerosols. During the first launch, an electric field experiment was also incorporated, while during the other two launches, Faraday rotation experiments yielded absolute electron number densities. During all three rocket flights a PMSE was observed by the VHF radar, whereas the potassium lidar detected a noctilucent cloud (NLC) only during the second launch. Signatures of charged particles forming the PMSE and NLC layers were recorded by the onboard particle detectors.

  9. Studies of high latitude mesospheric turbulence by radar and rocket. I - Energy deposition and wave structure

    NASA Technical Reports Server (NTRS)

    Goldberg, R. A.; Fritts, D. C.; Chou, H.-G.; Schmidlin, F. J.; Barcus, J. R.

    1988-01-01

    The origin of wintertime mesospheric echoes observed with the mesosphere-stratosphere-troposphere radar at Poker Flat, Alaska, was studied by probing the mesosphere with in situ rocket measurements during echo occurrences in the early spring, 1985. Within the height range 65-75 km, the structure of the large scale wave field was identified. In this region, a gravity wave with a vertical wavelength of about 2 km was found superimposed on a wave with a larger amplitude and a vertical wavelength of about 6.6 km. Because of the close correlation between the smaller amplitude wave and the modulation observed in the S/N profiles, it is concluded that the smaller wave was dominant in generating turbulence within the middle atmosphere.

  10. Studies of high latitude mesospheric turbulence by radar and rocket. II - Measurements of small scale turbulence

    NASA Technical Reports Server (NTRS)

    Blood, S. P.; Mitchell, J. D.; Croskey, C. L.; Raymund, T. D.; Thrane, E. V.; Blix, T. A.; Hoppe, U. P.; Fritts, D. C.; Schmidlin, F. J.

    1988-01-01

    Measurements of mesospheric small scale turbulence and associated larger scale wave structures were obtained from rocket probe flights during equinox in spring 1985. The measurements were verified by data from the mesosphere-stratosphere-troposphere radar at Poker Flat, Alaska. Electron density irregularities down to an altitude of about 62 km and fluctuations in positive ion density in the altitude region from 50 to 90 km were measured. Turbulence in the inertial subrange was observed at heights where the fluctuations generally were largest. Measurement of background electron density exhibited gradients relative to the monotonically increasing density profile, suggesting the presence of large amplitude wave motions transporting the plasma by mixing. The radar detected the occurrence of 1-3 km wavelike perturbations superimposed on a 7-km wave in the wind velocity field. It is suggested that the 1-3 km waves are more important in the transport of energy and momentum and in the production of turbulence in the lower mesosphere.

  11. Studies of high latitude mesospheric turbulence by radar and rocket. II - Measurements of small scale turbulence

    NASA Astrophysics Data System (ADS)

    Blood, S. P.; Mitchell, J. D.; Croskey, C. L.; Raymund, T. D.; Thrane, E. V.; Blix, T. A.; Hoppe, U. P.; Fritts, D. C.; Schmidlin, F. J.

    1988-11-01

    Measurements of mesospheric small scale turbulence and associated larger scale wave structures were obtained from rocket probe flights during equinox in spring 1985. The measurements were verified by data from the mesosphere-stratosphere-troposphere radar at Poker Flat, Alaska. Electron density irregularities down to an altitude of about 62 km and fluctuations in positive ion density in the altitude region from 50 to 90 km were measured. Turbulence in the inertial subrange was observed at heights where the fluctuations generally were largest. Measurement of background electron density exhibited gradients relative to the monotonically increasing density profile, suggesting the presence of large amplitude wave motions transporting the plasma by mixing. The radar detected the occurrence of 1-3 km wavelike perturbations superimposed on a 7-km wave in the wind velocity field. It is suggested that the 1-3 km waves are more important in the transport of energy and momentum and in the production of turbulence in the lower mesosphere.

  12. Model/data comparisons of ozone in the upper stratosphere and mesosphere

    NASA Technical Reports Server (NTRS)

    Siskind, David E.; Remsberg, Ellis E.; Eckman, Richard S.; Connor, Brian J.; Tsou, J. J.; Parrish, Alan

    1994-01-01

    We compare ground-based microwave observations of ozone in the upper stratosphere and mesosphere with daytime observations made from the SME (Solar Mesosphere Explorer) satellite, with nighttime data from the LIMS instrument, and with a diurnal photochemical model. The results suggest that the data are all in reasonable agreement and that the model-data discrepancy is much less than previously thought, particularly in the mesosphere. This appears to be due to the fact that the latest data are lower than earlier reports and the updated model predicts more ozone than older versions. The model and the data agree to within a factor of 1.5 at all altitudes and typically are within 20 percent.

  13. Carbon dioxide and oxygen isotope anomalies in the mesosphere and stratosphere

    SciTech Connect

    Thiemens, M.H.; Jackson, T.; Zipf, E.C.

    1995-11-10

    Isotopic ({delta}{sup 17}O and {delta}{sup 18}O) measurements of stratospheric and mesospheric carbon dioxide (CO{sub 2}) and oxygen (O{sub 2}), along with trace species concentrations (N{sub 2}O, CO, and CO{sub 2}), were made in samples collected from a rocket-borne cryogenic whole air sampler. A large mass-independent isotopic anomaly was observed in CO{sub 2}, which may in part derive from photochemical coupling to ozone (O{sub 3}). The data also require an additional isotopic fractionation process, which is presently unidentified. Mesospheric O{sub 2} isotope ratios differed from those in the troposphere and stratosphere. The cause of this isotopic variation in O{sub 2} is presently unknown. The inability to account for these observations represents a fundamental gap in the understanding of the O{sub 2} chemistry in the stratosphere and mesosphere. 28 refs., 2 figs., 1 tab.

  14. Daytime lidar measurements of tidal winds in the mesospheric sodium layer at Urbana, Illinois

    NASA Technical Reports Server (NTRS)

    Kwon, K. H.; Senft, D. C.; Gardner, C. S.; Voelz, D. G.; Sechrist, C. F., Jr.; Roesler, F. L.

    1986-01-01

    For more than 15 years lidar systems have been used to study the chemistry and dynamics of the mesospheric sodium layer. Because the layer is an excellent tracer of atmospheric wave motions, sodium lidar has proven to be particularly useful for studying the influence of gravity waves and tides on mesospheric dynamics. These waves, which originate in the troposphere and stratosphere, propagate through the mesosphere and dissipate their energy near the mesopause making important contributions to the momentum and turbulence budget in this region of the atmosphere. Recently, the sodium lidar was modified for daytime operation so that wave phenomena and chemical effects could be monitored throughout the complete diurnal cycle. The results of continuous 24 hour lidar observations of the sodium layer structure are presented alond with measurement of the semidiurnal tidal winds.

  15. Propagation of short period (10-40 min) atmospheric gravity waves from troposphere to mesosphere over Gadanki, India

    NASA Astrophysics Data System (ADS)

    Chakravarty, S. C.; Nagaraja, Kamsali

    2015-09-01

    The Indian MST radar at Gadanki (13.5°N, 79.2°E) has been utilised to conduct a detailed study of the close coupling between the troposphere and the mesosphere through the vertically propagating atmospheric gravity waves. For this purpose two cases from a special campaign dedicated to the simultaneous measurement of the fluctuations in the UTLS (Upper Troposphere and Lower Stratosphere) and in the mesosphere during 2001 and one case from a follow up observation in 2002 have been investigated. By using both the FFT and wavelet techniques, the near simultaneous tropospheric and mesospheric data of radar return signal strengths and tropospheric wind fields are analysed. The signatures of relatively high frequency gravity waves with periods between ~10 and 40 min have been clearly traced as propagating waves from the tropospheric turbulent layer heights (~8-18 km) to the lower mesospheric heights (65-80 km). Significant peak correlation coefficients of 0.56 and 0.45 have been found between the SNR time series of pairs of troposphere and mesosphere levels indicating the propagation of high speed gravity waves. The time series of wavelet spectra determined for the tropospheric SNR/zonal winds and the mesospheric SNR show that the detectability of the gravity waves increases at mesospheric heights. It is shown that the continuous SNR values received from the mesosphere can be used as an effective parameter for studies featuring mesospheric wave dynamics. Based on the observed values of vertical wavelengths and wave amplitudes, the horizontal wavelengths, wave phase and group velocities have been estimated for different wave periods. These results have implications on monitoring of the ubiquitous atmospheric gravity waves generated mainly by the tropospheric weather system of the tropical region from their imprint on the mesospheric turbulence structures.

  16. What is the temperature and carbon dioxide concentration in the mesosphere?

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.

    2011-12-01

    In a recent paper (Tuck et al., 2005) demonstrated that translationally hot oxygen atoms produced subsequent to ozone photolysis in the stratosphere implied the strong likelihood of non-Maxwell-Boltzmann (MB) molecular velocity distributions in the daytime. In other words, the stratospheric temperature is not characterized by a classic MB distribution. This would have implications, for example, for rates of chemical reactions and line shapes of radiatively active molecules, both of which are temperature dependent. In the mesosphere and lower thermosphere, where there is substantially more excess energy from photolysis and from energy released by exothermic chemical reactions, the likelihood of non-MB velocity distributions appears even higher. We review the generation of heat in the mesosphere and the production of hot atoms and molecules, discussing the possible generation of non-MB distributions, and hence the meaning of "temperature" in the mesosphere. We also discuss possible implications for radiative transfer, energy balance, and chemical composition in the mesosphere. In addition, understanding the energy balance in the mesosphere requires knowledge of the carbon dioxide concentration. Current remote measurement techniques face challenges due to the opacity of carbon dioxide in the infrared. Accurate in-situ measurements, coupled with satellite overflights offer high potential for substantial scientific progress in this critical area. We discuss the potential for new suborbital vehicles to make unique contributions to aeronomic science through the measurement of temperature and carbon dioxide in the mesosphere. Tuck, A. F., et al., (2005), Molecular velocity distributions and generalized scale invariance in the turbulent atmosphere, Faraday Discuss., 130, 181-193. DOI: 10.1039/b410551f.

  17. Do the OH Meinel bands provide mesospheric temperatures?

    NASA Astrophysics Data System (ADS)

    Slanger, Tom

    2016-04-01

    It is customary to determine local temperatures in the mesosphere and MLT by using Boltzmann plots based on the rotational distributions of the bands of the OH Meinel system, assuming that populations in these levels are in local thermodynamic equilibrium (LTE) with the kinetic temperature [Beig et al., Rev. Geophys., 2003; Turnbull and Lowe, PSS, 1989; von Savigny and Lednyts'kyy, GRL, 2013]. It has long been known that the higher rotational levels are not in LTE [Dodd et al., JGR,1994], so that a conventional Boltzmann plot cannot be used to obtain a temperature - only the lowest rotational levels are used, in the hope that LTE for such levels is appropriate. Because the atmosphere is dynamically active, it is important that the OH bands be observed simultaneously, particularly if the intent is to compare apparent temperatures from different vibrational levels. Using sky spectra from the Keck II telescope and the ESI echelle spectrograph, it has been shown that the LTE assumption seems to be invalid even for low rotational levels, based on earlier observations that show a reproducible pattern of apparent temperature vs OH vibrational level, with a general upward trend of temperature with increasing vibrational level, averaging 15-20 K [Cosby and Slanger, Can. J. Phys, 2007]. This work has now been repeated with a much larger database. using the X-shooter telescope and echelle spectrograph at the VLT (Very Large Telescope) in Chile [Noll et al., ACPD, 2015]. The results are in close accord with the earlier work, showing the same general pattern, with a marked temperature maximum at OH(v = 8), and an upward "temperature" trend from v = 2 to v = 9. As the OH layer lies below the mesopause, kinetic temperatures should fall from that layer ( 87 km) to the mesopause, near 95 km. Typically the modeled temperature in the OH layer is 17 K higher than that in the O2(b,v=0) layer [NRLMSIS00]. Rocket and satellite experiments indicate that there is a trend in altitude of the

  18. Lidar observations of mesospheric Fe and sporadic Fe layers at Urbana, Illinois

    NASA Technical Reports Server (NTRS)

    Bills, Richard E.; Gardner, Chester S.

    1990-01-01

    Lidar measurements of mesospheric Fe at Urbana, Illinois were conducted during 4 nights in October, 1989. The average Fe abundances were in the range (1.0-2.0) X 10 to the 10/sq cm. The layer centroid heights range between 89.0 and 90.5 km and the rms widths vary between 3.2 and 4.1 km. Considerable gravity wave and tidal activity are observed in the Fe profiles. The observations are compared with previous measurements of mesospheric Fe and with observations of sporadic Na (Na/S/) layers.

  19. Method for remotely measuring the spin-damping time of mesospheric sodium.

    PubMed

    Li, Lihang; Wang, Hongyan; Hua, Weihong; Ning, Yu; Xu, Xiaojun

    2016-09-01

    By using the return flux enhancement factor due to repumping, the spin-damping time of mesospheric sodium can be estimated. Because the absolute return photon number does not need to be measured, this method is independent of sodium abundance. An example of how to find the spin-damping time using this method is given. As a result, it is shown that this method is sensitive and has the potential to improve the precision of the spin-damping time estimations of mesospheric sodium. Finally, the impact of the geomagnetic field on this method is analyzed. PMID:27607983

  20. Characteristics of mesospheric optical emissions produced by lighting discharges

    NASA Astrophysics Data System (ADS)

    Veronis, Georgios; Pasko, Victor P.; Inan, Umran S.

    1999-06-01

    A new two-dimensional cylindrically symmetric electromagnetic model of the lightning-ionosphere interaction includes effects of both the lightning radiated electromagnetic pulses (EMP) and the quasi-electrostatic (QE) fields, thus allowing effective studies of lightning-ionosphere interactions on time scales ranging from several microseconds to tens of milliseconds. The temporal and spatial evolution of the electric field, lower ionospheric electron density, and optical emissions calculated with the new model are used to investigate theoretically the effects of the lightning return stroke current waveform (i.e., the current rise and fall timescales) and of the observational geometry on the optical signals observed with a photometer. For typical lightning discharges of ~100 μs duration the ionospheric response is dominated by the EMP-induced heating leading to the highly transient and laterally expanding optical flashes known as elves. The optical signal characteristics are found to be highly sensitive to both the observational geometry and the current waveform. The onset delay with respect to the lighting discharge, the duration, and the peak magnitude of optical emissions are highly dependent on the elevation and azimuth angles of field of view of individual photometric pixels. The shape of the optical signal clearly reflects the source current waveform. For a waveshape with risetime of ~50 μs or longer a double-pulse shape of the photometric signal is observed. For cloud to ground lightning discharges of ~1 ms duration removing substantial amount of charge (i.e., ~100 C from 10 km altitude), heating and ionization changes induced by the QE field lead to the mesospheric luminous glows with lateral extent <100 km, referred to as sprites.

  1. The mesospheric metal layer topside: a possible connection to meteoroids

    NASA Astrophysics Data System (ADS)

    Höffner, J.; Friedman, J. S.

    2004-05-01

    In the past, many studies have been carried out to demonstrate the influence of meteoroids on the atmospheric metal layer, observed roughly in the altitude range 80-105 km. Even with the capability of present day resonance lidars to measure metal densities within single meteor trails, it has been difficult to prove any influence of meteors on the average metal layer. In contrast to approaches taken earlier, we discuss here the seasonal characteristics of potassium, calcium, calcium ion, iron and sodium above 110 km altitude where the average nocturnal densities are so low that the existence of a baseline level of metal atoms and ions is often overlooked. By comparing simultaneous and common-volume observations of different metal layers at one location, we demonstrate that despite their different seasonal characteristics at lower altitudes remarkably similar seasonal characteristics are observed at higher altitudes. In addition, a qualitative agreement is also found for potassium at different latitudes. A comparison of metal densities at 113 km altitude with known meteor showers indicates a strong influence of shower meteoroids on the topside of the metal layers. Simultaneous observations of K along with Ca, Fe and/or Na permit the calculation of abundance ratios, which at 113 km altitude are quite similar to values measured in single meteor trails by ground based lidars. Furthermore, the increase in densities throughout summer is strong evidence for the influence of sporadic meteoroids on the high metal layers. This increase correlates well with the seasonal variation of sporadic micrometeor input independent of meteor showers. Given these evidences, we contend that there is a direct influence of ablating meteoroids on the topside of the mesospheric metal layer.

  2. Nucleation of mesospheric cloud particles: Sensitivities and limits

    NASA Astrophysics Data System (ADS)

    Wilms, Henrike; Rapp, Markus; Kirsch, Annekatrin

    2016-03-01

    Nucleation of mesospheric ice particles is thought to occur via heterogeneous nucleation on meteor smoke particles. However, several factors determining the nucleation rate are poorly known. To study the effect of uncertainties in the nucleation rate on cloud properties, we use the Community Aerosol and Radiation Model for Atmospheres and systematically vary the nucleation rate over ±10 orders of magnitude. In one set of simulations, the background state of the atmosphere is described by climatological conditions. In a second set, gravity wave-perturbed profiles from the Kühlungsborn Mechanistic general Circulation Model (KMCM) are used with typical temperature (vertical wind) perturbations at the mesopause on the order of 9 K (0.45 m/s). The resulting noctilucent cloud (NLC) characteristics are compared to lidar and satellite measurements. Realistic NLCs compared to the lidar measurements can only be modeled if the nucleation rate is reduced by up to 3 orders of magnitude compared to standard assumptions. For the same cases, the simulated NLCs compare best to the satellite measurements if the nucleation rate is reduced by 2 orders of magnitude or more. Dynamical processes at the mesopause strongly influence the NLC development. In a gravity wave-perturbed atmosphere, the ice particles have only limited time for nucleation and growth. The growth time is limited by the vertical wind, because the vertical wind determines the residence time of the ice particles in the supersaturated region. Since the vertical wind amplitudes reach 1.5 m/s in KMCM (compared to a mean upwelling of ˜4 cm/s in the climatology), the ice particles remain significantly smaller in a gravity wave-perturbed atmosphere than in climatological background conditions.

  3. A New Paradigm for Ionosphere-Thermosphere-Mesosphere Physics

    NASA Astrophysics Data System (ADS)

    Fuller-Rowell, Tim

    2015-04-01

    The ionosphere-thermosphere-mesosphere system is predominantly a neutral atmosphere domain with a fairly small fraction, less than 1%, that is ionized, similar in some ways to the chromosphere. Neutral dynamics and composition therefore play an important role in influencing and controlling the ionospheric plasma density and creating structure. Neutral thermospheric dynamics is driven from both above and below. Absorption of solar extreme ultraviolet radiation drives a global circulation, and magnetosphere/ionosphere plasma convection can accelerate neutral winds in excess of 1 km/s through collisions, and raise gas temperature by hundreds of degrees Kelvin by frictional dissipation. During extreme events these solar and magnetospheric sources dominate the ITM system, and understanding the plethora of physical processes that ensue has been the focus for more than 50 years. However, the bulk of solar energy reaching Earth penetrates well into the lower atmosphere and to the surface. Even if only a small fraction of this large energy reservoir can reach above 100 km it can have a significant impact on the ITM system and its variability. The main dynamic coupling and transfer of energy from below is largely through atmospheric waves, particularly tides (waves with harmonics of the 24 hour solar day), and gravity waves from the multitude of sources in the lower atmosphere. We now appreciate that dynamical changes and warmings in the stratosphere from changes in planetary wave activity can lead to a 50% change in electron content in the ionosphere, and which can actually be forecast days in advance. Tropospheric convection over continental landmass imprints a longitude structure on the ionosphere. Convective adjustment, extreme weather, wind shear, airflow over mountains, are some of the many sources of gravity waves activity that can grow in amplitude as they propagate into the thermosphere where they modulate and tilt the ionosphere. The ITM system is dynamic and

  4. First experimental verification of summertime mesospheric momentum balance based on radar wind measurements at 69° N

    NASA Astrophysics Data System (ADS)

    Placke, M.; Hoffmann, P.; Rapp, M.

    2015-09-01

    Gravity waves (GWs) greatly influence the background state of the middle atmosphere by imposing their momentum on the mean flow upon breaking and by thus driving, e.g., the upper mesospheric summer zonal wind reversal. In this situation momentum is conserved by a balance between the vertical divergence of GW momentum flux (the so-called GW drag) and the Coriolis acceleration of the mean meridional wind. In this study, we present first quantitative mean annual cycles of these two balancing quantities from the medium frequency Doppler radar at the polar site Saura (SMF radar, 69° N, 16° E). Three-year means for 2009 through 2011 clearly show that the observed zonal momentum balance between 70 and 100 km with contributions from GWs only is fulfilled during summer when GW activity is strongest and more stable than in winter. During winter, the balance between GW drag and Coriolis acceleration of the mean meridional wind is not existent, which is likely due to the additional contribution from planetary waves, which are not considered by the present investigation. The differences in the momentum balance between summer and winter conditions are additionally clarified by 3-month mean vertical profiles for summer 2010 and winter 2010/2011.

  5. Charge and size distribution of mesospheric aerosol particles measured inside NLC and PMSE during MIDAS MaCWAVE 2002

    NASA Astrophysics Data System (ADS)

    Smiley, B.; Rapp, M.; Blix, T. A.; Robertson, S.; Horányi, M.; Latteck, R.; Fiedler, J.

    2006-01-01

    During the MIDAS MaCWAVE sounding rocket campaign performed at Andøya, Norway (16°E, 69°N), from 29 June to 5 July 2002, charged aerosol probes aboard a MIDAS rocket detected a mixture of charged aerosol particles with different charges and sizes. Two charged aerosol probes were used on the MIDAS payload. The first probe, a collection surface shielded by a magnetic field, was optimized for the detection of negative aerosol particles. The second probe, a collection surface shielded by a magnetic field and a positive bias voltage, was optimized for detecting positive aerosol particles. On 2 July 2002, a MIDAS payload was launched into a simultaneous noctilucent cloud (NLC) and polar mesospheric summer echo (PMSE). The two probes measured a charge and size distribution of aerosol particles: a narrow layer of both small (1 nm

  6. Mesospheric signatures observed during 2010 minor stratospheric warming at King Sejong Station (62°S, 59°W)

    NASA Astrophysics Data System (ADS)

    Eswaraiah, S.; Kim, Yong Ha; Hong, Junseok; Kim, Jeong-Han; Ratnam, M. Venkat; Chandran, A.; Rao, S. V. B.; Riggin, Dennis

    2016-03-01

    A minor stratospheric sudden warming (SSW) event was noticed in the southern hemisphere (SH) during September (day 259) 2010 along with two episodic warmings in early August (day 212) and late October (day 300) 2010. Among the three warming events, the signature of mesosphere response was detected only for the September event in the mesospheric wind dataset from both meteor radar and MF radar located at King Sejong Station (62°S, 59°W) and Rothera (68°S, 68°W), Antarctica, respectively. The zonal winds in the mesosphere reversed approximately a week before the September SSW event, as has been observed in the 2002 major SSW. Signatures of mesospheric cooling (MC) in association with stratospheric warmings are found in temperatures measured by the Microwave Limb Sounder (MLS). Simulations of specified dynamics version of Whole Atmosphere Community Climate Model (SD-WACCM) are able to reproduce these observed features. The mesospheric wind field was found to differ significantly from that of normal years probably due to enhanced planetary wave (PW) activity before the SSW. From the wavelet analysis of wind data of both stations, we find that strong 14-16 day PWs prevailed prior to the SSW and disappeared suddenly after the SSW in the mesosphere. Our study provides evidence that minor SSWs in SH can result in significant effects on the mesospheric dynamics as in the northern hemisphere.

  7. Inter-Hemispheric Coupling During Recent North Polar Summer Periods as Predicted by MaCWAVE/MIDAS Rocket Data and Traced by TIMED/SABER Measurements

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Feofilov, Artem G.; Kutepov, Alexander A.; Pesnell W. Dean; Schmidlin, Francis J.

    2011-01-01

    In July, 2002, the MaCWAVE-MIDAS Rocket Program was launched from Andoya Rocket Range (ARR) in Norway. Data from these flights demonstrated that the polar summer mesosphere during this period was unusual, at least above ARR. Theoretical studies have since been published that imply that the abnormal characteristics of this polar summer were generated by dynamical processes occurring in the southern polar winter hemisphere. We have used data from the SABER instrument aboard the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) Satellite to study these characteristics and compare them with the features observed in the ensuing eight years. For background, the TIMED Satellite was launched on December 7,2001 to study the dynamics and energy of the mesosphere and lower thermosphere. The SABER instrument is a limb scanning infrared radiometer designed to measure temperature of the region as well as a large number of minor constituents. In this study, we review the MaCWAVE rocket results. Next, we investigate the temperature characteristics of the polar mesosphere as a function of spatial and temporal considerations. We have used the most recent SABER dataset (1.07). Weekly averages are used to make comparisons between the winter and summer hemispheres. Furthermore, the data analysis agrees with recent theoretical studies showing that this behavior is a result of anomalous dynamical events in the southern hemisphere. The findings discussed here clearly show the value of scientific rocket flights used in a discovery mode.

  8. Characterization of Dusty Plasmas in the Earth's Mesosphere Using Radiowave Heating

    SciTech Connect

    Scales, Wayne; Chen, Chen

    2008-09-07

    Recently it has become evident that significant diagnostic information may be available to characterize charged sub-visible mesospheric dust layers from the temporal behavior of the associated electron irregularities during radiowave heating which ultimately modifies the mesospheric electron temperature. Particularly important time periods of the irregularity temporal behavior are during the turn-on and turn-off of the radio wave heating. The objective of this work is to first consider the physical processes that control the evolution of electron irregularities associated with mesospheric dust layers during radio wave heating. It is shown that two dominant processes are dust charging and ambipolar diffusion. In particular, it will be shown that a fundamental parameter that controls the temporal behavior is the ratio of the dust charging to ambipolar diffusion time during the turn-on and turn-off period. Both computational and analytical models are described that may be used to directly investigate the electron irregularity temporal evolution with particular emphasis placed on modeling the electron irregularity temporal evolution during the time periods when the radio wave heating is turned on and off. The models results may then be used to obtain diagnostic information on the characteristics of the charged dust layer, such as dust density and radius. Predictions of the models are used to describe possibilities for new experiments that may provide further diagnostic information on charged mesospheric dust layers.

  9. Mesospheric sodium airglow emission: Modeling and first results over a mid-latitude

    NASA Astrophysics Data System (ADS)

    Bag, Tikemani; Krishna, M. V. Sunil; Singh, Vir

    2016-07-01

    Atmospheric sodium plays a very important role in the mesospheric chemistry and dynamics. We have developed a comprehensive model for mesospheric/thermospheric sodium airglow emission by incorporating all the known reaction mechanisms. The latest reaction rate coefficients and the related cross sections are obtained from the theoretical studies and experimental observations. The continuity equations are explicitly solved for the major species. Similarly, the steady-state approximation has been used for the intermediate and short lived minor species. The number densities from in-situ observations, NRLMSISE-00, and IRI-2012 have been successfully implemented to calculate the vertical volume emission rate. The modeled results compared to a good agreement with the measured profiles of Na airglow emission. The mesospheric sodium density shows a large day-to-day variability. The observed variations in the mesospheric sodium layer have been incorporated to obtain the variations in the sodium airglow intensities. The nocturnal variation of sodium airglow emissions are presented over a mid latitude location using this model.

  10. Effect of trends of middle atmosphere gases on the mesosphere and thermosphere

    NASA Astrophysics Data System (ADS)

    Qian, Liying; Marsh, Daniel; Merkel, Aimee; Solomon, Stanley C.; Roble, Raymond G.

    2013-06-01

    We conducted model simulations to examine how changes in concentration of radiatively active trace gases in the middle atmosphere affect long-term changes in the upper atmosphere. We focused our model study on the impact of increases in carbon dioxide (CO2), methane (CH4), and water vapor (H2O), and decreases in ozone (O3) between 1983 and 2003. We used both the National Center for Atmospheric Research Whole Atmosphere Community Climate Model and the Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model, global mean version, in this study. The model simulations indicate that CO2 is the main forcing mechanism of long-term changes in the thermsophere, with minor influences from O3, CH4, and H2O. At 400 km altitude, global mean thermospheric neutral density decreased by ~4.5% due to CO2 forcing alone, whereas it decreased by ~4.8% due to the combined forcing from all four gases. O3 depletion caused cooling in the stratosphere and mesosphere (maximum decrease of 0.5 K) due to reduced absorption of solar ultraviolet radiation, but had nearly no cooling effect in the thermosphere. However, due to thermal contraction in the stratosphere and mesosphere, O3 depletion caused a small decrease in thermospheric neutral density of ~0.25%. Increases in both CH4 and H2O may slightly warm the upper mesosphere and thermosphere due to increased chemical heating and absorption of solar ultraviolet radiation.

  11. Solar and chemical reaction-induced heating in the terrestrial mesosphere and lower thermosphere

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.

    1992-01-01

    Airglow and chemical processes in the terrestrial mesosphere and lower thermosphere are reviewed, and initial parameterizations of the processes applicable to multidimensional models are presented. The basic processes by which absorbed solar energy participates in middle atmosphere energetics for absorption events in which photolysis occurs are illustrated. An approach that permits the heating processes to be incorporated in numerical models is presented.

  12. Lasers and the Dynamic Mesosphere/Thermosphere of Venus

    NASA Technical Reports Server (NTRS)

    Kostiuk, Theodor; Fast, Kelly E.; Livengood, Timothy A.; Schmuelling, Frank; Hewagama, Tilak; Annen, John; Buhl, David; Sonnabend, Guido; Sornig, Manuela; Kroetz, Peter; Goldstein, Jeffrey

    2010-01-01

    A review of ground based mid-infrared uniquely high spectral. resolution measurements of Venus dynamics, temperature, and chemistry will be presented. The described studies will focus on the use of CO2 absorption features and the discovery- and use of CO2 thermospheric non-thermal emission: lines as probes of Venus' atmosphere, from the cloud tops to approx.120 km in the thermosphere. The first investigations using infrared heterodyne spectroscopy with resolving power lambda/Delta(lambda) approx. 10(exp 6) to measure true emission line profiles and to determine their non-thermal nature and lasing component will be described. The use of the thermospheric non-thermal CO2 emission to directly measure sub-solar to anti-solar winds and zonal circulation near 110 km altitudes on Venus to approx.2 m/s accuracy will also be described. The measured emission lures are also used to obtain global maps of mesospheric/thermospheric kinetic and rotational temperatures as well as to obtain evidence of the natural lasing phenomena. Carbon dioxide absorption features globally probe lower altitudes in the atmosphere and can be used to determine nightside temperatures. Isotopic 13 CO2 absorption lines are used to probe deeper in the atmosphere to measure the sub-solar to anti-solar return flow at altitudes just above the cloud tops. These results provided a model for global circulation in the 65 - 120 km altitude region first proposed by Goldstein (1989, PhD.Thesis, U. Pennsylvania, Philadelphia, USA). Results of similar wind and temperature measurements made in recent years will be compared to earlier results to investigate changes in the circulation and temperatures since approx.1990. The high resolution infrared heterodyne technique was also used to investigate chemical processes above the cloud tops, specifically evidence and constraints on oxygen-based chemistry. Described measurements were made by infrared heterodyne spectroscopy using the Goddard Space Flight Center Infrared

  13. In situ observations of small scale neutral and plasma dynamics in the mesosphere / lower thermosphere at 79° N.

    NASA Astrophysics Data System (ADS)

    Strelnikov, B.; Rapp, M.; Blix, T. A.; Wilms, S.; Engler, N.; Höffner, J.; Lübken, F.-J.; Smiley, B.; Friedrich, M.

    From June 29 to July 7 2003, the German-Norwegian ROMA/SVALRAK campaign (ROMA = Rocket borne Observations in the Middle Atmosphere) took place at the SVALRAK rocket range, Ny-Ålesund (79°N, 11°E; Spitsbergen). The main scientific aim of this campaign was to study polar mesosphere summer echoes (PMSE) and mesospheric turbulence. During this campaign a total of three instrumented sounding rockets was launched. In addition, ground based observations with a VHF radar and a potassium lidar at Longyearbyen complemented the in situ measurements. All three sounding rockets were equipped with the CONE (= COmbined sensor for Neutrals and Electrons) instrument to measure small scale structure of neutral air and electron density, and neutral temperature. The PIP (= Positive Ion Probe) instrument was used to measure small scale structure of the positive ion density. Furthermore, two cold plasma probes (CPP) were used to measure electron temperature, and a particle detector was employed to detect signatures of charged aerosols. During the first launch, an electric field experiment was also incorporated, while during the other two launches, Faraday rotation experiments yielded absolute electron number densities. During all three rocket flights a PMSE was observed by the VHF radar, whereas the potassium lidar detected a noctilucent cloud (NLC) only during the second launch. Signatures of the charged particles forming the PMSE and NLC layers were recorded by the onboard particle detectors. During the first launch neutral air density fluctuations indicating turbulence in the altitude region from ˜ 74 km up to ˜ 90 km were detected by the CONE instrument. In addition, CONE recorded very strong and high frequency neutral density fluctuations between altitudes of 90 km up to the apogee of ˜ 106 km. Clearly, these fluctuations are of non-turbulent origin. Strong positive ion and electron density fluctuations were also detected in the same altitude region (˜ 90 -106 km). These

  14. Variability of mesospheric water vapor above Bern in relation to the 27-day solar rotation cycle

    NASA Astrophysics Data System (ADS)

    Lainer, Martin; Hocke, Klemens; Kämpfer, Niklaus

    2016-06-01

    Many studies investigated solar-terrestrial responses (thermal state, O3, OH, H2O) with emphasis on the tropical upper atmosphere. In this paper the focus is switched to water vapor in the mesosphere at a mid-latitudinal location. Eight years of water vapor profile measurements above Bern (46.88 ° N / 7.46 ° E) are investigated to study oscillations with the focus on periods between 10 and 50 days. Different spectral analyses revealed prominent features in the 27-day oscillation band, which are enhanced in the upper mesosphere (above 0.1 hPa, ∼ 64 km) during the rising sunspot activity of solar cycle 24. Local as well as zonal mean Aura MLS observations support these results by showing a similar behavior. The relationship between mesospheric water and the solar Lyman-α flux is studied by comparing the similarity of their temporal oscillations. The H2O oscillation is negatively correlated to solar Lyman-α oscillation with a correlation coefficient of up to - 0.3 to - 0.4, and the phase lag is 6-10 days at 0.04 hPa. The confidence level of the correlation is ≥ 99 %. This finding supports the assumption that the 27-day oscillation in Lyman-α causes a periodical photodissociation loss in mesospheric water. Wavelet power spectra, cross-wavelet transform and wavelet coherence analysis (WTC) complete our study. More periods of high common wavelet power of H2O and solar Lyman-α are present when amplitudes of the Lyman-α flux increase. Since this is not a measure of physical correlation a more detailed view on WTC is necessary, where significant (two sigma level) correlations occur intermittently in the 27 and 13-day band with variable phase lock behavior. Large Lyman-α oscillations appeared after the solar superstorm in July 2012 and the H2O oscillations show a well pronounced anti-correlation. The competition between advective transport and photodissociation loss of mesospheric water vapor may explain the sometimes variable phase relationship of mesospheric H2

  15. Sensitivity Analysis for Characterizing the Accuracy and Precision of JEM/SMILES Mesospheric O3

    NASA Astrophysics Data System (ADS)

    Esmaeili Mahani, M.; Baron, P.; Kasai, Y.; Murata, I.; Kasaba, Y.

    2011-12-01

    The main purpose of this study is to evaluate the Superconducting sub-Millimeter Limb Emission Sounder (SMILES) measurements of mesospheric ozone, O3. As the first step, the error due to the impact of Mesospheric Temperature Inversions (MTIs) on ozone retrieval has been determined. The impacts of other parameters such as pressure variability, solar events, and etc. on mesospheric O3 will also be investigated. Ozone, is known to be important due to the stratospheric O3 layer protection of life on Earth by absorbing harmful UV radiations. However, O3 chemistry can be studied purely in the mesosphere without distraction of heterogeneous situation and dynamical variations due to the short lifetime of O3 in this region. Mesospheric ozone is produced by the photo-dissociation of O2 and the subsequent reaction of O with O2. Diurnal and semi-diurnal variations of mesospheric ozone are associated with variations in solar activity. The amplitude of the diurnal variation increases from a few percent at an altitude of 50 km, to about 80 percent at 70 km. Although despite the apparent simplicity of this situation, significant disagreements exist between the predictions from the existing models and observations, which need to be resolved. SMILES is a highly sensitive radiometer with a few to several tens percent of precision from upper troposphere to the mesosphere. SMILES was developed by the Japanese Aerospace eXploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT) located at the Japanese Experiment Module (JEM) on the International Space Station (ISS). SMILES has successfully measured the vertical distributions and the diurnal variations of various atmospheric species in the latitude range of 38S to 65N from October 2009 to April 2010. A sensitivity analysis is being conducted to investigate the expected precision and accuracy of the mesospheric O3 profiles (from 50 to 90 km height) due to the impact of Mesospheric Temperature

  16. On the Observed Changes in Upper Stratospheric and Mesospheric Temperatures from UARS HALOE

    NASA Technical Reports Server (NTRS)

    Remsberg, Ellis E.

    2006-01-01

    Temperature versus pressure or T(p) time series from the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite (UARS) have been extended and re-analyzed for the period of 1991-2005 and for the upper stratosphere and mesosphere in 10-degree wide latitude zones from 60S to 60N. Even though sampling from a solar occultation experiment is somewhat limited, it is shown to be quite adequate for developing both the seasonal and longer-term variations in T(p). Multiple linear regression (MLR) techniques were used in the re-analyses for the seasonal and the significant interannual, solar cycle (SC-like or decadal-scale), and linear trend terms. A simple SC-like term of 11-yr period was fitted to the time series residuals after accounting for the seasonal and interannual terms. Highly significant SC-like responses were found for both the upper mesosphere and the upper stratosphere. The phases of these SC-like terms were checked for their continuity with latitude and pressure-altitude, and in almost all cases they are directly in-phase with that of standard proxies for the solar flux variations. The analyzed, max minus min, responses at low latitudes are of order 1 K, while at middle latitudes they are as large as 3 K in the upper mesosphere. Highly significant, linear cooling trends were found at middle latitudes of the middle to upper mesosphere (about -2 K/decade), at tropical latitudes of the middle mesosphere (about -1 K/decade), and at 2 hPa (or order -1 K/decade).

  17. Detection of Long-Term Temperature Changes in the Stratosphere and Mesosphere

    NASA Astrophysics Data System (ADS)

    Yee, J.; Swartz, W. H.; Mlynczak, M. G.; Russell, J. M.

    2010-12-01

    Over the past five decades, temporal and spatial changes in the Earth's Stratosphere and Mesosphere have been documented by measurements by numerous rocket/satellite borne and groundbased in-situ and remote sensing instruments. These datasets have allowed us to gain physical insights into processes that control the observed changes through high-fidelity physics-based first-principle models. These processes, although being complex because of their mutual coupling nature, they, however, can generally be attributed to two distinct origins: the Sun above and the human below. NASA'S Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) mission, over the past eight and half years, has provided an excellent quantitative description of the upper atmosphere variabilities. Its observations, covering near an entire solar cycle, along with other worldwide network of groundbased and satellite observations of the stratosphere/mesosphere/thermosphere/ ionosphere system have transformed our understanding of this gateway region of near-Earth space by successfully characterizing its physics, dynamics, energetics, composition and thermal structures in the context of solar induced variabilities. It is clear that without measurements in at least one or more solar cycle, it is impossible to separate out the relative effects of solar driving, inter-annual lower atmosphere variability, and the long-term human-induced changes. Combining measurements covering several solar cycles are clearly needed. However, these measurements have generally been taken by different sensors on different platforms using different sensing techniques. In this paper, we will present nearly three decades of stratospheric and mesospheric temperature measurements from LIMS, HALOE/UARS, MLS/UARS, SABER/TIMED, COSMIC, CHAMP, MLS/Aura, and assess their measurement qualities for decadal-scale temperature change studies. The systematic measurement biases among these datasets will be documented, and

  18. Energetic electrons and their effects on upper stratospheric and mesospheric ozone in May 1992

    NASA Astrophysics Data System (ADS)

    Pesnel, W. Dean; Goldberg, Richard A.; Chenette, D. L.; Gaines, E. E.; Jackman, Charles H.

    The increased fluxes of precipitating energetic electrons (E>1 MeV) during highly relativistic electron events (HREs) produce ion concentrations in the upper stratosphere and lower mesosphere that exceed the background concentrations. Coupled ion-neutral chemistry models predict that this increased ionization should drive HOχ reactions and deplete mesospheric ozone by up to roughly 25%. As HREs become more intense and frequent during the declining phase of the solar cycle, it was also predicted that mesospheric ozone would show a solar cycle modulation as a result of these events. To calibrate the effect HREs have on mesospheric ozone, we have studied the May 1992 HRE with several instruments on the UARS. Electron fluxes measured with HEPS give the duration and spatial coverage of the HRE. Ozone data from MLS, CLAES, and HRDI were examined for the chemical signature of the HRE, ozone depletions within the magnetic L-shell limits of 3≤L<4. Using the multiple viewing angles of HRDI, we can compare mesospheric ozone at similar local solar times before, during, and after the HRE. This removes some of the ambiguity caused by progressive sampling of the diurnal cycle over a yaw cycle of the satellite. Although we analyzed one of the most intense HREs in the UARS database, we did not find HRE-induced changes in the ozone mixing ratio between altitudes of 55-75 km. Detecting a long-term trend in the ozone driven by precipitating electrons appears to require a substantial increase in the signal-to-noise ratio of the satellite measurements.

  19. New measurements of vertical thermal structure and wind velocities in the Venusian mesosphere

    NASA Astrophysics Data System (ADS)

    Widemann, T.; Sandor, B. J.; Clancy, R. T.; Lellouch, E.

    2009-04-01

    The Venus mesosphere is a highly variable transition region, in latitude, local time and over short time scales, between the zonal circulation of the lower atmosphere and the diurnal, sub-solar to anti-solar circulation in the upper atmosphere. In the framework of European Space Agency's second campaign of ground-based observations (Feb 8-22, 2009) in support of the Venus-Express mission, we coordinated new observations sampling a large range of altitudes in the Venus mesosphere on Feb. 7-8 and Feb. 14-15 : (1) James Clerk Maxwell Submillimeter Telescope (JCMT) submillimeter lines observations of mesospheric CO spectral lines measurements of temperature, CO mixing ratio and winds over the 95-115 km altitude range (Clancy et al., 2008), while SO2, SO and HDO observations were also probed in the 70-100 km range ; (2) Canada-France-Hawaii Telescope (CFHT) optical spectropolarimeter ESPaDOnS observations of visible Solar Fraunhofer lines measuring the winds at cloud tops near 70 km and visible CO2 lines 1-2 scale heights above (Widemann et al., 2007, 2008). Synchronization of wind measurements helps characterize possible correlation patterns between wind variations in the lower and middle mesosphere over a day time scale. Preliminary results will be presented at the meeting. Clancy, R.T., Sandor, B.J., and Moriarty-Schieven, G.H. 2008, Planet. Space Sci. 56, 1320-1334. Widemann, T., Lellouch, E., and Campargue, A. 2007, New Wind Measurements in Venus' Lower Mesosphere From Visible Spectroscopy, Planet. Space Sci. 55, 1741-1756 Widemann, T., Lellouch, E., Donati, J.-F., 2008, Venus Doppler winds at Cloud Tops Observed with ESPaDOnS at CFHT, Planet. Space Sci. 56, 1320-133 --

  20. Is chemical heating a major cause of the mesosphere inversion layer?

    SciTech Connect

    Meriwether, J.W.; Mlynczak, M.G.

    1995-01-01

    A region of thermal enhancement of the mesosphere has been detected on numerous occasions by in situ measurements, remote sensing from space, and lidar techniques. The source of these `temperature inversion layers` has been attributed in the literature to the dissipation relating to dynamical forcing by gravity wave or tidal activity. However, evidence that gravity wave breaking can produce the inversion layer with amplitude as large as that observed in lidar measurements has been limited to results of numerical modeling. An alternative source for the production of the thermal inversion layer in the mesosphere is the direct deposition of heat by exothermic chemical reactions. Two-dimensional modeling combining a comprehensive model of the mesosphere photochemistry with the dynamical transport of long-lived species shows that the region from 80 to 95 km may be heated as much as 3 to 10 K/d during the night and half this rate during the day. Given the uncertainties in our understanding of the dynamics and chemistry for the mesopause region, separating the two sources by passive observations of the mesosphere thermal structure looks to be difficult. Therefore we have considered an active means for producing a mesopause thermal layer, namely the release of ozone into the upper mesosphere from a rocket payload. The induced effects would include artificial enhancements of the OH and Na airglow intensities as well as the mesopause thermal structure. The advantages of the rocket release of ozone is that detection of these effects by ground-based imaging, radar, and lidar systems and comparison of these effects with model predictions would help quantify the partition of the artificial inversion layer production into sources of dynamical and chemical forcing.

  1. Variability of mesospheric water vapor above Bern in relation to the 27-day solar rotation cycle

    NASA Astrophysics Data System (ADS)

    Lainer, Martin; Hocke, Klemens; Kämpfer, Niklaus

    2016-04-01

    We investigate the solar-terrestrial response of mesospheric water vapor from a mid-latitudinal observation site at the 27-day solar rotation cycle time scale. Eight years of water vapor profile measurements above Bern (46.88°N/7.46°E) by the microwave radiometer MIAWARA are used to study prominent oscillation features. The spectral data analyses shows enhanced oscillations in the 27-day period band above 0.1hPa during the rising sunspot activity of solar cycle 24. Aura MLS observations of H2O support these results by showing a similar behavior. The relationship between mesospheric H2O and the solar Lyman-α flux (FLyα) is studied by comparing the similarity of their temporal oscillations. The H2O oscillation is negatively correlated to FLyα oscillation with a correlation coefficient of up to ‑0.3 to ‑0.4, and the phase lag is 6-10 days on 0.04hPa. The confidence level of the correlation is ≥ 99%. Additionally we compute wavelet power spectra, cross-wavelet transform and wavelet coherence (WTC). The latter shows significant (two σ level) correlations occurring intermittently in the 27 and 13-day band with variable phase lock behavior. Large FLyα oscillations appeared after the solar superstorm in July 2012 and the H2O oscillations show a well pronounced anti-correlation. The competition between advective transport and photo-dissociation loss of mesospheric H2O may explain the sometimes variable phase relationship of mesospheric H2O and FLyα oscillations. Generally, the WTC analysis indicates that solar variability causes observable photochemical and dynamical processes in the mid-latitude mesosphere.

  2. The formation of multiple layers of ice particles in the polar summer mesopause region

    NASA Astrophysics Data System (ADS)

    Li, H.; Wu, J.; Zhou, Z.

    2016-01-01

    This paper presents a two-dimensional theoretical model to study the formation process of multiple layers of small ice particles in the polar summer mesosphere as measured by rockets and associated with polar mesosphere summer echoes (PMSE). The proposed mechanism primarily takes into account the transport processes induced by gravity waves through collision coupling between the neutral atmosphere and the ice particles. Numerical solutions of the model indicate that the dynamic influence of wind variation induced by gravity waves can make a significant contribution to the vertical and horizontal transport of ice particles and ultimately transform them into thin multiple layers. Additionally, the pattern of the multiple layers at least partially depends on the vertical wavelength of the gravity wave, the ice particle size and the wind velocity. The results presented in this paper will be helpful to better understand the occurrence of multiple layers of PMSE as well as its variation process.

  3. Mesosphere-to-stratosphere descent of odd nitrogen in February-March 2009 after sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Salmi, S.-M.; Verronen, P. T.; Thölix, L.; Kyrölä, E.; Backman, L.; Karpechko, A. Yu.; Seppälä, A.

    2011-01-01

    We use the 3-D FinROSE chemistry transport model (CTM) and ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer) observations to study the connection between atmospheric dynamics and NOx descent during early 2009 in the northern polar region. We force the model NOx at 80 km poleward of 60° N with ACE-FTS observations and then compare the model results with observations at lower altitudes. Low geomagnetic indices indicate absence of local NOx production in early 2009, which gives a good opportunity to study the effects of atmospheric transport on polar NOx. No in-situ production of NOx by energetic particle precipitation is therefore included. This is the first model study using ECMWF (The European Centre for Medium-Range Weather Forecasts) data up to 80 km and simulating the exceptional winter of 2009 with one of the strongest major sudden stratospheric warmings (SSW). The model results show a strong NOx descent in February-March 2009 from the upper mesosphere to the stratosphere after the major SSW. Both observations and model results suggest an increase of NOx to 150-200 ppb (i.e. by factor of 50) at 65 km due to the descent following the SSW. The model, however, underestimates the amount of NOx around 55 km by 40-60 ppb. The results also show that the chemical loss of NOx was insignificant i.e. NOx was mainly controlled by the dynamics. Both ACE-FTS observations and FinROSE show a decrease of ozone of 20-30% at 30-50 km after mid-February to mid-March. However, these changes are not related to the NOx descent, but are due to activation of the halogen chemistry.

  4. Tracing the Inter-Hemispheric Coupling During Polar Summer Periods of 2002-2010 Using TIMED/SABER Measurements

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard; Feoflow, Artem; Pesnell, Dean; Kutepov, Alexander

    2010-01-01

    It has been found that for more than one polar summer season between 2002-2010, the northern polar mesospheric region near and above the mesospheric maximum was warmer than normal. The strongest warming effect of this type was observed to occur during northern summer 2002. Theoretical studies have implied that these "anomalies" were preceded by unusual dynamical processes occurring in the southern hemisphere. We have analyzed temperature distributions measured by the SABER limb scanning infrared radiometer aboard the NASA TIMED satellite between 2002-2010 at altitudes from 15 to 110 km and for latitudes between 83 deg. S to 83 deg. N. We describe the approach to trace the inter-hemispheric temperature correlatoins and to identify the global features that were unique for the "anomalous" northern polar summers.

  5. Diurnal Variations of Meteoric Fe Layers in the Mesosphere and Lower Thermosphere at McMurdo (77.8°S, 166.7°E), Antarctica

    NASA Astrophysics Data System (ADS)

    Yu, Z.; Chu, X.; Huang, W.; Fong, W.

    2011-12-01

    As one of the main metal species in the mesosphere and lower thermosphere, neutral Fe layers provide an excellent tracer for studying atmospheric dynamics and chemistry. Unfortunately, most Fe measurements were made in the night, except a few reports from the Antarctic and Arctic. So far studies of the diurnal variations of Fe layers are very rare. This situation poses interesting questions like how Fe layers vary through a diurnal cycle, whether such variations change with seasons, and what mechanisms contribute to the diurnal variations. To help address this issue, we report the diurnal variations of Fe densities, based on our lidar observations made at McMurdo, Antarctica. The data were collected with an Fe Boltzmann lidar since late December 2010 through austral autumn, winter and spring in 2011, covering the states of polar days under full sunlight, alternations between day and night, and polar nights under total darkness. By taking composite days, we obtain 24-h Fe coverage for every month, allowing relatively detailed study of the diurnal variations. Our preliminary analyses show an interesting phenomenon that the bottom boundary of Fe layers extends downward from ~80 km to ~75 km or lower when switching from night to day. This phenomenon is obvious in continuous (straight) 24-h data as well as in composite 24-h data during March and April when the sunlight conditions have day and night switches. The results indicate that photochemistry, rather than wave dynamics, may play an essential role in determining the Fe layer bottom. No obvious diurnal variations are observed in polar summer and mid-winter; however, the layer bottom altitude descends for several kilometers from polar day to polar night. These likely reflect the influences of temperatures, waves, mesospheric clouds and aurora activities.

  6. The seasonal variation of water vapor and ozone in the upper mesosphere - Implications for vertical transport and ozone photochemistry

    NASA Technical Reports Server (NTRS)

    Bevilacqua, Richard M.; Summers, Michael E.; Strobel, Darrell F.; Olivero, John J.; Allen, Mark

    1990-01-01

    This paper reviews the data base supplied by ground-based microwave measurements of water vapor in the mesosphere obtained in three separate experiments over an eight-year period. These measurements indicate that the seasonal variation of water vapor in the mesosphere is dominated by an annual component with low values in winter and high values in summer, suggesting that the seasonal variation of water vapor in the mesosphere (below 80 km) is controlled by advective rather than diffusive processes. Both the seasonal variation and the absolute magnitude of the water vapor mixing ratios obtained in microwave measurements were corroborated by measurements obtained in the Spacelab GRILLE and ATMOS experiments, and were found to be consistent with several recent mesospheric dynamics studies.

  7. Mesospheric effects of solar ultraviolet variations - Further analysis of SME IR ozone and Nimbus 7 SAMS temperature data

    NASA Technical Reports Server (NTRS)

    Hood, L. L.; Huang, Z.; Bougher, S. W.

    1991-01-01

    In order to improve the constraints on models of the mesospheric response to solar UV variations, an analysis is conducted of the Solar Mesosphere Explorer (SME) IR ozone data and Nimbus 7 stratosphere and mesosphere sounder (SAMS) temperature data. Maximum low-altitude ozone and temperature-response amplitudes occur at about the same altitude, where a strong coupling between photochemical and thermal components of the mesospheric response is suggested by the simultaneous positive temperature and negative ozone response maxima. Increased Lyman-alpha dissociation of water vapor and temperature feedback are theorized to account for the negative ozone response. HO(x) chemical heating can increase as ozone destruction increases, and can therefore account for the positive temperature response.

  8. High resolution mesospheric sodium properties for adaptive optics applications

    NASA Astrophysics Data System (ADS)

    Pfrommer, T.; Hickson, P.

    2014-05-01

    Context. The performance of laser guide star adaptive optics (AO) systems for large optical and infrared telescopes is affected by variability of the sodium layer, located at altitudes between 80 and 120 km in the upper mesosphere and lower thermosphere. The abundance and density structure of the atomic sodium found in this region is subject to local and global weather effects, planetary and gravity waves and magnetic storms, and is variable on time scales down to tens of milliseconds, a range relevant to AO. Aims: It is therefore important to characterize the structure and dynamical evolution of the sodium region on small, as well as large spatial and temporal scales. Parameters of particular importance for AO are the mean sodium altitude, sodium layer width and the temporal power spectrum of the centroid altitude. Methods: We have conducted a three-year campaign employing a high-resolution lidar system installed on the 6-m Large Zenith Telescope (LZT) located near Vancouver, Canada. During this period, 112 nights of useful data were obtained. Results: The vertical density profile of atomic sodium shows remarkable structure and variability. Smooth Gaussian-shaped profiles rarely occur. Multiple internal layers are frequently found. These layers often have sharp lower edges, with scale heights of just a few hundred meters, and tend to drift downwards at a typical rate of one kilometer every two to three hours. Individual layers can persist for many hours, but their density and internal structure can be highly variable. Sporadic layers are seen reaching peak densities several times the average, often in just a few minutes. Coherent vertical oscillations are often found, typically extending over tens of kilometers in altitude. Regions of turbulence are evident and Kelvin-Helmholtz instability are sometimes seen. The mean value of the centroid altitude is found to be 90.8 ± 0.1 km. The sodium layer width was determined by computing the altitude range that contains a

  9. Climatology and first-order composition estimates of mesospheric clouds from Mars Climate Sounder limb spectra

    NASA Astrophysics Data System (ADS)

    Sefton-Nash, E.; Teanby, N. A.; Montabone, L.; Irwin, P. G. J.; Hurley, J.; Calcutt, S. B.

    2013-01-01

    Mesospheric clouds have been previously observed on Mars in a variety of datasets. However, because the clouds are optically thin and most missions have performed surface-focussed nadir sounding, geographic and seasonal coverage is sparse. We present new detections of mesospheric clouds using a limb spectra dataset with global coverage acquired by NASA's Mars Climate Sounder (MCS) aboard Mars Reconnaissance Orbiter. Mesospheric aerosol layers, which can be CO2 ice, water ice or dust clouds, cause high radiances in limb spectra, either by thermal emission or scattering of sunlight. We employ an object recognition and classification algorithm to identify and map aerosol layers in limb spectra acquired between December 2006 and April 2011, covering more than two Mars years. We use data from MCS band A4, to show thermal signatures of day and nightside features, and A6, which is sensitive to short wave IR and visible daytime features only. This large dataset provides several thousand detections of mesospheric clouds, more than an order of magnitude more than in previous studies. Our results show that aerosol layers tend to occur in two distinct regimes. They form in equatorial regions (30°S-30°N) during the aphelion season/northern hemisphere summer (Ls < 150°), which is in agreement with previous published observations of mesospheric clouds. During perihelion/dust storm season (Ls > 150°) a greater number of features are observed and are distributed in two mid-latitude bands, with a southern hemisphere bias. We observe temporal and longitudinal clustering of cloud occurrence, which we suggest is consistent with a formation mechanism dictated by interaction of broad temperature regimes imposed by global circulation and the propagation to the mesosphere of small-scale dynamics such as gravity waves and thermal tides. Using calculated frost point temperatures and a parameterization based on synthetic spectra we find that aphelion clouds are present in generally cooler

  10. A compact receiver system for simultaneous measurements of mesospheric CO and O3

    NASA Astrophysics Data System (ADS)

    Forkman, P.; Christensen, O. M.; Eriksson, P.; Billade, B.; Vassilev, V.; Shulga, V. M.

    2016-02-01

    During the last decades, ground-based microwave radiometry has matured into an established remote sensing technique for measuring vertical profiles of a number of gases in the stratosphere and the mesosphere. Microwave radiometry is the only ground-based technique that can provide vertical profiles of gases in the upper stratosphere and mesosphere both day and night, and even during cloudy conditions. Except for microwave instruments placed at high-altitude sites, or at sites with dry atmospheric conditions, only molecules with significant emission lines below 150 GHz, such as CO, H2O, and O3, can be observed. Vertical profiles of these molecules can give important information about chemistry and dynamics in the middle atmosphere. Today these measurements are performed at relatively few sites; more simple and reliable instrument solutions are required to make the measurement technique more widely spread. This need is urgent today as the number of satellite sensors observing the middle atmosphere is about to decrease drastically. In this study a compact double-sideband frequency-switched radiometer system for simultaneous observations of mesospheric CO at 115.27 GHz and O3 at 110.84 GHz is presented. The radiometer, its calibration scheme, and its observation method are presented. The retrieval procedure, including compensation of the different tropospheric attenuations at the two frequencies and error characterization, are also described. The first measurement series from October 2014 until April 2015 taken at the Onsala Space Observatory, OSO (57° N, 12° E), is analysed. The retrieved vertical profiles are compared with co-located CO and O3 data from the MLS instrument on the Aura satellite. The data sets from the instruments agree well with each other. The main differences are the higher OSO volume mixing ratios of O3 in the upper mesosphere during the winter nights and the higher OSO volume mixing ratios of CO in the mesosphere during the winter. The low bias

  11. A~compact receiver system for simultaneous measurements of mesospheric CO and O3

    NASA Astrophysics Data System (ADS)

    Forkman, P.; Christensen, O. M.; Eriksson, P.; Billade, B.; Vassilev, V.; Shulga, V. M.

    2015-09-01

    During the last decades, ground-based microwave radiometry has matured to an established remote sensing technique for measuring vertical profiles of a number of gases in the stratosphere and the mesosphere. Microwave radiometry is the only ground-based technique that can provide vertical profiles of gases in the upper stratosphere and mesosphere both day and night, and even during cloudy conditions. Except for microwave instruments placed at high altitude sites, or at sites with dry atmospheric conditions, only molecules with significant emission lines below 150 GHz, such as CO, H2O and O3 can be observed. Vertical profiles of these molecules can give important information about chemistry and dynamics in the middle atmosphere. Today these measurements are performed at relatively few sites, more simple and reliable instrument solutions are required to make the measurement technique more widely spread. This need is today urgent as the number of satellite sensors observing the middle atmosphere is about to decrease drastically. In this study a compact double-sideband frequency-switched radiometer system for simultaneous observations of mesospheric CO at 115.27 GHz and O3 at 110.84 GHz is presented The radiometer, its calibration scheme and observation method are presented. The retrieval procedure, including compensation of the different tropospheric attenuation at the two frequencies, and error characterization are also described. The first measurement series from October 2014 until April 2015 taken at the Onsala Space Observatory, OSO, (57° N, 12° E) is analysed. The retrieved vertical profiles are compared with co-located CO and O3 data from the MLS instrument on the Aura satellite. The datasets from the instruments agree well to each other. The main differences are the higher OSO volume mixing ratios of O3 in the upper mesosphere during the winter nights and the higher OSO volume mixing ratios of CO in the mesosphere during the winter. The low bias of mesospheric

  12. Development of a stratospheric and mesospheric microwave temperature sounder experiment

    NASA Technical Reports Server (NTRS)

    Staelin, D. H.; Rosenkranz, P. W.; Anderson, B. G.; Kunzi, K. F.; Paroskie, R. M.; Parr, R. J.; Waters, J. W.

    1975-01-01

    A passive microwave spectrometer system for measuring global atmospheric temperature profiles from 0-75 km altitude was developed and analyzed. The system utilizes 12 channels near the 5 mm wavelength oxygen absorption band and is designed to provide global coverage by scanning perpendicular to the orbital track of a polar orbiting satellite. A significant improvement in the accuracy of theoretical atmospheric microwave transmittance functions was achieved through the development of a first-order approximation to overlapping line theory for the oxygen molecule. This approximation is particularly important in the troposphere and lower stratosphere where pressure-broadening blends nearby lines. Ground-based and aircraft observations of several resonances of stratospheric oxygen generally support the theory. The 23, 25, 29, and 31 atmospheric oxygen lines were measured and the frequencies of several such oxygen lines were measured with improved precision. The polarization and Zeeman splitting of the atmospheric 27 line was also observed.

  13. On the seasonal variations of reflectivity and turbulence characteristics of low-latitude mesospheric echoes over Gadanki

    NASA Astrophysics Data System (ADS)

    Selvaraj, D.; Patra, A. K.; Narayana Rao, D.

    2016-06-01

    Gadanki radar observations of the low-latitude mesospheric echoes studied earlier have shown that while both occurrence rate and signal-to-noise ratio of the mesospheric echoes peak in the equinoxes turbulent kinetic energy (TKE) dissipation rate and eddy diffusivity, estimated using spectral width of these echoes, peak in the summer. This seasonal difference is apparently inconsistent with the understanding that the mesospheric echoes are generated by turbulence. In this paper, we analyze Gadanki radar observations of mesospheric echoes made during 2011 and 2012 and study seasonal variations in reflectivity and TKE dissipation rate in an attempt to address the aforementioned puzzle. We show that both reflectivity and TKE dissipation rate in the mesosphere show semiannual variations peaking in the equinoxes, which are vastly different from those reported earlier. We also show that seasonal variations in reflectivity and TKE dissipation rate have a close correspondence with gravity wave activity. These results are found to be consistent with the gravity wave breaking hypothesis generating turbulence and radar echoes in the low-latitude mesosphere.

  14. Molecular content of polar-ring galaxies

    NASA Astrophysics Data System (ADS)

    Combes, F.; Moiseev, A.; Reshetnikov, V.

    2013-06-01

    We have searched for CO lines in a sample of 21 new morphologically determined polar-ring galaxies (of which nine are kinematically confirmed), obtained from a wide search in the Galaxy Zoo project by Moiseev and collaborators. Polar-ring galaxies (PRGs) are a unique class of objects, tracing special episodes in the galaxy mass assembly: they can be formed through galaxy interaction and merging, but also through accretion from cosmic filaments. Furthermore, they enable the study of dark matter haloes in three dimensions. The polar ring itself is a sub-system rich in gas, where molecular gas is expected, and new stars are formed. Among the sample of 21 PRGs, we have detected five CO-rich systems, that can now be followed up with higher spatial resolution. Their average molecular mass is 9.4 × 109M⊙, and their average gas fraction is 27% of their baryonic mass, with a range from 15 to 43%, implying that they have just accreted a large amount of gas. The position of the detected objects in the velocity-magnitude diagram is offset from the Tully-Fisher relation of normal spirals, as was already found for PRGs. This work is part of our multi-wavelength project to determine the detailed morphology and dynamics of PRGs, test through numerical models their formation scenario, and deduce their dark matter content and 3D-shape. Based on observations carried out with the IRAM 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).Spectra of detections are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5">130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/554/A11

  15. Some aspects of metallic ion chemistry and dynamics in the mesosphere and thermosphere

    NASA Technical Reports Server (NTRS)

    Mathews, J. D.

    1987-01-01

    The relationship between the formation of sporadic layers of metallic ion and the dumping of these ions into the upper mesosphere is discussed in terms of the tidal wind, classical (i.e., windshear) and other more complex, perhaps highly nonlinear layer formation mechanisms, and a possible circulation mechanism for these ions. Optical, incoherent scatter radar, rocket, and satellite derived evidence for various layer formation mechanisms and for the metallic ion circulation system is reviewed. The results of simple one dimensional numerical model calculations of sporadic E and intermediate layer formation are presented along with suggestions for more advanced models of intense or blanketing sporadic E. The flux of metallic ions dumped by the tidal wind system into the mesosphere is estimated and compared with estimates of total particle flux of meteoric origin. Possible effects of the metallic ion flux and of meteoric dust on D region ion chemistry are discussed.

  16. Understanding the Latitude Structure of Nitric Oxide in the Mesosphere and Lower Thermosphere

    NASA Technical Reports Server (NTRS)

    Fuller-Rowell, T.J.

    1997-01-01

    The goal of the proposed work was to understand the latitude structure of nitric oxide in the mesosphere and lower thermosphere. The problem was portrayed by a clear difference between predictions of the nitric oxide distribution from chemical/dynamical models and data from observations made by the Solar Mesosphere Explorer (SMEE) in the early to mid eighties. The data exhibits a flat latitude structure of NO, the models tend to produce at equatorial maximum. The first task was to use the UARS-HALOE data to confirm the SME observations. The purpose of this first phase was to verify the UARS-NO structure is consistent with the SME data. The next task was to determine the cause of the discrepancy between modeled and observed nitric oxide latitude structure. The result from the final phase indicated that the latitude structure in the Photo-Electron (PE) production rate was the most important.

  17. Mesospheric gravity waves and ionospheric plasma bubbles observed during the COPEX campaign

    NASA Astrophysics Data System (ADS)

    Paulino, I.; Takahashi, H.; Medeiros, A. F.; Wrasse, C. M.; Buriti, R. A.; Sobral, J. H. A.; Gobbi, D.

    2011-07-01

    During the Conjugate Point Experiment (COPEX) campaign performed at Boa Vista (2.80∘N;60.70∘W, dip angle21.7∘N) from October to December 2002, 15 medium-scale gravity waves in the OHNIR airglow images were observed. Using a Keogram image analysis, we estimate their parameters. Most of the waves propagate to Northwest, indicating that their main sources are Southeast of Boa Vista. Quasi-simultaneous plasma bubble activities in the OI 630 nm images were observed in seven cases. The distances between the bubble depletions have a linear relationship with the wavelengths of the gravity waves observed in the mesosphere, which suggests a direct contribution of the mesospheric medium-scale gravity waves in seeding the equatorial plasma bubbles.

  18. SABER observations of mesospheric ozone during NH late winter 2002-2009

    NASA Astrophysics Data System (ADS)

    Smith, A. K.; López-Puertas, M.; García-Comas, M.; Tukiainen, S.

    2009-12-01

    Observations from the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) instrument on the TIMED (Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics) satellite show interannual variations of mesospheric ozone in the NH late winter. Ozone in the mid-January to mid-March period is significantly different in 2004, 2006, and 2009 than in other years (2002, 2003, 2005, 2007, 2008). The altitudes of the ozone secondary maximum (˜90-95 km), the minimum (˜80 km) and the tertiary maximum (˜72 km) are all lower by 3-5 km during the three anomalous winters. The ozone anomalies indicate enhanced downward motion and are consistent with other observations of unusual profiles of trace species. The ozone perturbations extend to at least 100 km while temperatures above 90 km are within the range found in the other years.

  19. Ground-based microwave observations of ozone in the upper stratosphere and mesosphere

    SciTech Connect

    Connor, B.J.; Siskind, D.E.; Tsou, J.J.; Parrish, A.; Remsberg, E.E. |||

    1994-08-01

    A 9-month-long series of mesurements of ozone in the upper stratosphere and mesosphere is reported. The measurements are presented as monthly averages of profiles in blocks of roughly 20 min local time and as night-to-day ratios. An error analysis predicts accuracies of 5-26% for the monthly profiles and 2.5-9% for the ratios. The data are compared to historical data from Solar Mesosphere Explorer (SME) and limb infrared monitor of the stratosphere (LIMS), and it is shown how to remove the effect of different vertical resolution from the comparisons. The microwave data typically agree to better than 10% with SMF and nighttime LIMS ozone at all altitudes below the 0.1-mbar surface. Comparison of the microwave night-to-day ratio with the corresponding ratio from LIMS suggests that nonlocal thermodynamic equilibrium effects in the LIMS daytime data exceed 10% at all pressures less than or equal to 1 mbar.

  20. Vertical transport and photochemistry in the terrestrial mesosphere and lower thermosphere /50-120 km/

    NASA Technical Reports Server (NTRS)

    Allen, M.; Yung, Y. L.; Waters, J. W.

    1981-01-01

    A study is conducted of the coupled effects of kinetics, solar cycle flux variations, and vertical transport on the distribution of long-lived hydrogen-carbon-oxygen compounds in the terrestrial mesosphere and lower thermosphere, using a one-dimensional aeronomy model. The calculations account for the important chemical reactions and use rocket measurements of the solar flux at solar minimum and maximum. Photodissociation rates appropriate for the mesosphere are determined with a spherical shell atmosphere formalism. Detailed corrections for the O2 Schumann-Runge bands and the temperature dependence of the CO2 cross sections are used. An eddy diffusion profile is derived which is in agreement with the Aladdin 74 mass spectral measurements of atomic O, O2, CO2, and Ar in the lower thermosphere and observations of the O3 minimum at about 80 km.

  1. Gravity wave activities in the stratosphere and mesosphere during sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Li, Tao; Leblanc, Thierry; McDermid, I. Stuart; Riggin, Dennis; Fritts, Dave C.

    The gravity wave activities in the stratosphere and mesosphere of subtropics during the sudden stratospheric warming were studied using the temperature profiles measured by the Jet Propul-sion Laboratory (JPL) Rayleigh lidar at Mauna Loa Observatory (19.5N, 195.6W), Hawaii, and horizontal wind profiles measured by the MF radar at Kauai (22N, 200.2W), Hawaii. We found that the significant enhancement of gravity wave activities was observed before the sudden stratospheric warming in winter 2005/2006, followed by the decrease of activity during and after the warming. The significant change of GW activities during the warming will be dis-cussed together with the ECMWF wind in the stratosphere and MF radar mean wind in the mesosphere.

  2. Ground-based microwave observations of ozone in the upper stratosphere and mesosphere

    NASA Technical Reports Server (NTRS)

    Connor, Brian J.; Siskind, David E.; Tsou, J. J.; Parrish, Alan; Remsberg, Ellis E.

    1994-01-01

    A 9-month-long series of mesurements of ozone in the upper stratosphere and mesosphere is reported. The measurements are presented as monthly averages of profiles in blocks of roughly 20 min local time and as night-to-day ratios. An error analysis predicts accuracies of 5-26% for the monthly profiles and 2.5-9% for the ratios. The data are compared to historical data from Solar Mesosphere Explorer (SME) and limb infrared monitor of the stratosphere (LIMS), and it is shown how to remove the effect of different vertical resolution from the comparisons. The microwave data typically agree to better than 10% with SMF and nighttime LIMS ozone at all altitudes below the 0.1-mbar surface. Comparison of the microwave night-to-day ratio with the corresponding ratio from LIMS suggests that nonlocal thermodynamic equilibrium effects in the LIMS daytime data exceed 10% at all pressures less than or equal to 1 mbar.

  3. The Ames two-dimensional stratosphere-mesospheric model. [chemistry and transport of SST pollution

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Borucki, W. J.; Watson, V. R.; Capone, L. A.; Maples, A. L.; Riegel, C. A.

    1974-01-01

    A two-dimensional model of the stratosphere and mesosphere has recently been developed at Ames Research Center. The model contains chemistry based on 18 species that are solved for at each step and a seasonally-varying transport model based on both winds and eddy transport. The model is described and a preliminary assessment of the impact of supersonic aircraft flights on the ozone layer is given.

  4. Development of a mesospheric sodium laser beacon for atmospheric adaptive optics. (Reannouncement with new availability information)

    SciTech Connect

    Jeys, T.H.

    1991-12-31

    The authors have developed laser sources of sodium-resonance radiation based on the sum-frequency mixing of Nd:YAG laser radiation. The sources are suitable for generating a fluorescence spot in the earth`s mesospheric sodium layer for use in adaptive optics compensation. Taking into account the sodium fluorescence lifetime, Doppler broadening, hyperfine structure, radiative saturation, optical pumping, and radiation pressure, we can optimize the intensity of the fluorescence by using spectral and temporal tailoring of the laser radiation.

  5. Mesospheric wind measurements using a medium-frequency imaging Doppler interferometer

    NASA Technical Reports Server (NTRS)

    Adams, G. W.; scatterers.

    1986-01-01

    Wind results from a medium-frequency radar operated as an imaging Doppler interferometer are presented. Ten independent antennas, together with mesospheric wind motions, were used to Doppler-sort and then echo-locate individual scattering points. The three-dimensional location and radial velocity of each discrete scattering point was determined. Mean winds were then determined by a least squares fit to the radial velocities of the ensemble of scatterers.

  6. Development of Ultra-Thin Polyethylene Balloons for High Altitude Research upto Mesosphere

    NASA Astrophysics Data System (ADS)

    Kumar, B. Suneel; Nagendra, N.; Ojha, D. K.; Peter, G. Stalin; Vasudevan, R.; Anand, D.; Kulkarni, P. M.; Reddy, V. Anmi; Rao, T. V.; Sreenivasan, S.

    Ever since its inception four decades back, Balloon Facility of Tata Institute of Fundamental Research (TIFR), Hyderabad has been functioning with the needs of its user scientists at its focus. During the early nineties, when the X-ray astronomy group at TIFR expressed the need for balloons capable of carrying the X-ray telescopes to altitudes up to 42 km, the balloon group initiated research and development work on indigenous balloon grade films in various thickness not only for the main experiment but also in parallel, took up the development of thin films in thickness range 5 to 6 μm for fabrication of sounding balloons required for probing the stratosphere up to 42 km as the regular 2000-gram rubber balloon ascents could not reach altitudes higher than 38 km. By the year 1999, total indigenization of sounding balloon manufacture was accomplished. The work on balloon grade ultra-thin polyethylene film in thickness range 2.8 to 3.8 μm for fabrication of balloons capable of penetrating mesosphere to meet the needs of user scientists working in the area of atmospheric dynamics commenced in 2011. Pursuant to the successful trials with 61,000-m3 balloon made of 3.8-μm Antrix film reaching stratopause (48 km) for the first time in the history of balloon facility in the year 2012, fine tuning of launch parameters like percentage free lift was carried out to take the same volume balloons to higher mesospheric altitudes. Three successful flights with a total suspended load of 10 kg using 61,000-m3 balloons were carried out in the month of January 2014 and all the three balloons crossed into the mesosphere reaching altitudes of over 51 km. All the balloons flown so far are closed system with no escape ducts. Balloon fabrication, development of launch hardware, flight control instruments and launch technique for these mesospheric balloon flights are discussed in this paper.

  7. Vertical profile of δ18OOO from the middle stratosphere to lower mesosphere from SMILES spectra

    NASA Astrophysics Data System (ADS)

    Sato, T. O.; Sagawa, H.; Yoshida, N.; Kasai, Y.

    2014-04-01

    Ozone is known to have large oxygen isotopic enrichments of about 10% in the middle stratosphere; however, there have been no reports of ozone isotopic enrichments above the middle stratosphere. We derived an enrichment δ18OOO in the stratosphere and the lower mesosphere from observations of the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard the International Space Station (ISS) using a retrieval algorithm optimized for the isotopic ratio. The retrieval algorithm includes (i) an a priori covariance matrix constrained by oxygen isotopic ratios in ozone, (ii) an optimization of spectral windows for ozone isotopomers and isotopologues, and (iii) common tangent height information for all windows. The δ18OOO by averaging the SMILES measurements at the latitude range of 20 to 40° N from February to March in 2010 with solar zenith angle < 80° was 13% (at 32 km) with the systematic error of about 5%. SMILES and past measurements were in good agreement, with δ18OOO increasing with altitude between 30 and 40 km. The vertical profile of δ18OOO obtained in this study showed an increase and a decrease with altitude in the stratosphere and mesosphere, respectively. The δ18OOO peak, 18%, is found at the stratopause. The δ18OOO has a positive correlation with temperature in the range of 220-255 K, indicating that temperature can be a dominant factor to control the vertical profile of δ18OOO in the stratosphere and mesosphere. This is the first report of the observation of δ18OOO over a wide altitude range extending from the stratosphere to the mesosphere (28-57 km).

  8. High-Resolution Temperature Mapping of Mesospheric Gravity Waves and Breaking Events

    NASA Astrophysics Data System (ADS)

    Taylor, Michael J.; Pautet, Pierre-Dominique; Zhao, Yucheng; Yuan, Tao; Pendleon, William R.; Fritts, David; Esplin, Roy; McLain, David; Stober, Gunter

    2016-04-01

    This presentation highlights new research capabilities and recent results using a novel infra-red imaging system operating at high-latitudes at the ALOMAR Arctic Observatory, Norway (69°N), and at Amundsen-Scott South Pole Station, Antarctica (90°S). The Advanced Mesospheric Temperature Mapper (AMTM) is a high-performance digital imaging system that measures selected emission lines in the mesospheric OH (3,1) band (at ~1.55 μm) to create high-quality intensity and temperature maps of a broad spectrum of gravity waves at the ~87 km level (with periods ranging from several minutes to many hours). The temperature data are obtained with an unprecedented spatial (~0.5 km) and temporal (typically 30 sec) resolution over a large 120° field of view enabling detailed studies of gravity wave propagation and breaking events in the Mesosphere and Lower Thermosphere (MLT) region, even in the presence of strong aurora and moonlight. New results include high-resolution wintertime studies of continuous (24-hr) gravity wave activity and spectral evolution, and first evidence of gravity wave "self-acceleration" in the MLT region using coordinated lidar and radar measurements. These results are complemented by very high resolution (~4 sec) gravity wave observations using a third AMTM developed for airborne measurements on the National Science Foundation (NSF) Gulfstream V aircraft as part of the DEEPWAVE program. This mission was successfully conducted from New Zealand during the Austral winter, June-July 2014, and obtained spectacular new data on mesospheric mountain waves, including large amplitude breaking events associated with variable orographic forcing over the Southern Alps.

  9. One: Microphysics of frost metamorphism: Applications to Triton and Mars. Two: A global analysis of the ozone deficit in the upper stratosphere and lower mesosphere. Three: The diabatic circulation in the stratosphere as diagnosed from Microwave Limb Sounder data

    SciTech Connect

    Eluszkiewicz, J.B.

    1993-01-01

    The present thesis is devoted to two broad subjects, planetary frost metamorphism and the terrestrial middle atmosphere, and consists of three papers. Paper 1 considers frost metamorphism on the surfaces of Triton and Mars. Based on an analysis of the microphysical processes involved in the pressureless sintering, it is concluded that fine-grained nitrogen and carbon dioxide frosts can undergo seasonal metamorphism into semitransparent layers on the surface of Triton and in the Martian seasonal polar caps, respectively. The presence of such layers explains a host of facts about Triton's surface and about the Martian seasonal caps. Paper 2 is devoted to elucidating a long-standing issue in the terrestrial middle atmosphere chemistry, the so-called 'ozone deficit problem.' Based on an analysis of data acquired by the Limb Infrared Monitor of the Stratosphere (LIMS) instrument between October 1978 and May 1979, it is concluded that current photochemical models systematically underestimate observed ozone abundances in the upper stratosphere and lower mesosphere. Three modifications to the accepted photochemical scheme, capable of providing a global solution to this problem, are proposed and discussed. Paper 3 differs from the other two in that it reports on results from an ongoing research effort. It considers the diabatic circulation in the stratosphere and lower mesosphere, using ozone and temperature measurements acquired by the Microwave Limb Sounder (MLS) instrument onboard the Upper Atmosphere Research Satellite (UARS). The present study extends past analyses of the diabatic circulation by considering a full annual cycle, November 1991-November 1992, and by taking advantage of the high vertical resolution of MLS data. In the tropical upper stratosphere and lower mesosphere, a semiannual oscillation (SAO) is observed in the computed circulation, with the region of downwelling reaching maximum spatial extent approximately 1 month before the equinox.

  10. Mesospheric Response to Strong and Weak Orographic Forcing During the DEEPWAVE Project

    NASA Astrophysics Data System (ADS)

    Pautet, P. D.; Taylor, M. J.; Fritts, D. C.; Williams, B. P.; Bossert, K.

    2015-12-01

    Gravity waves (GWs) are one of the main drivers of the Earth's atmosphere as they vertically couple energy and momentum throughout its successive layers. Orographic forcing is a well-known source for these waves which can impact the stratosphere (Eckermann and Preusse, 1999), and even the mesosphere (Smith et al., 2009). During the months of June and July 2014, a large-scale project named DEEPWAVE took place in New Zealand. This international program focused on investigating the generation and deep propagation of atmospheric gravity waves, especially over the mountain range of the Southern Alps. A series of instruments was operated at several ground-based locations and on-board the NSF Gulfstream V aircraft. 25 nighttime research flights were performed to explore possible wave sources and their effects on the middle and upper atmosphere. On 2 consecutive nights (29th and 30th June), research flights 12 and 13 were conducted over New Zealand South Island to compare the effects of 2 different wind forcing: strong during the first flight, then reduced on the following day. As the GV aircraft was repetitively flying over the Southern Alps, the mesospheric gravity wave field was measured using a series of newly developed instruments (Advanced Mesospheric Temperature Mapper, IR side cameras and lidars). This presentation will investigate the differences between the gravity waves observed during these 2 flights and the impact of distinct orographic forcing on the upper atmosphere.

  11. A Multi-Instrument Measurement of a Mesospheric Bore at the Equator

    NASA Technical Reports Server (NTRS)

    Shiokawa, K.; Suzuki, S.; Otsuka, Y.; Ogawa, T.; Nakamura, T.; Mlynczak, M. G.; Russell, J. M., III

    2005-01-01

    We have made a comprehensive measurement of mesospheric bore phenomenon at the equator at Kototabang, Indonesia (0.2 deg S, 100.3 deg E), using an airglow imager, an airglow temperature photometer, a meteor radar, and the SABER instrument on board the TIMED satellite. The bore was detected in airglow images of both OH-band (peak emission altitude: 87 km) and 557.7-nm (96 km) emissions, as east-west front-like structure propagating northward with a velocity of 52-58 m/s. Wave trains with a horizontal wavelength of 30-70 km are observed behind the bore front. The airglow intensity decreases for all the mesospheric emissions of OI (557.7 nm), OH-band, O2-band (altitude: 94 km), and Na (589.3 nm) (90 km) after the bore passage. The rotational temperatures of both OH-band and O2-band also decrease approximately 10 K after the bore passage. An intense shear in northward wind velocity of 80m/s was observed at altitudes of 84-90 km by the meteor radar. Kinetic temperature profile at altitudes of 20-120 km was observed near Kototabang by TIMED/SABER. On the basis of these observations, we discuss generation and ducting of the observed mesospheric bore.

  12. Solar activity influence on climatic variations of stratosphere and mesosphere in mid-latitudes

    NASA Technical Reports Server (NTRS)

    Taubenheim, J.; Entzian, G.; Voncossart, G.

    1989-01-01

    The direct modulation of temperature of the mid-latitude mesosphere by the solar-cycle EUV variation, which leads to greater heat input at higher solar activity, is well established. Middle atmosphere temperature modulation by the solar cycle is independently confirmed by the variation of reflection heights of low frequency radio waves in the lower ionosphere, which are regularly monitored over about 30 years. As explained elsewhere in detail, these reflection heights depend on the geometric altitude of a certain isobaric surface (near 80 k), and on the solar ionizing Lyman-alpha radiation flux. Knowing the solar cycle variation of Lyman-alpha how much the measured reflection heights would be lowered with the transition from solar minimum to maximum can be calculated, if the vertical baric structure of the neutral atmosphere would remain unchanged. An discrepancy between expected and observed height change must be explained by an uplifting of the isobaric level from solar minimum to maximum, caused by the temperature rise in the mesosphere. By integrating the solar cycle temperature changes over the height region of the middle atmosphere, and assuming that the lower boundary (tropopause) has no solar cycle variation, the magnitude of this uplifting can be estimated. It is given for the Lidar-derived and for the rocket-measured temperature variations. Comparison suggests that the real amplitude of the solar cycle temperature variation in the mesosphere is underestimated when using the rocket data, but probably overestimated with the Lidar data.

  13. Stratospheric and mesospheric HO2 observations from the Aura Microwave Limb Sounder

    NASA Astrophysics Data System (ADS)

    Millán, L.; Wang, S.; Livesey, N.; Kinnison, D.; Sagawa, H.; Kasai, Y.

    2014-09-01

    This study introduces stratospheric and mesospheric hydroperoxyl radical (HO2) estimates from the Aura Microwave Limb Sounder (MLS) using an offline retrieval (i.e. run separately from the standard MLS algorithm). This new dataset provides two daily zonal averages, one during daytime and one during nighttime, with a varying vertical resolution from about 4 km at 10 hPa to around 14 km at 0.0032 hPa. A description of the methodology and an error analysis are presented. Comparisons against the Whole Atmosphere Community Climate Model (WACCM), the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) and the Far Infrared Spectrometer (FIRS-2) measurements, as well as, photochemical simulations demonstrate the robustness of the retrieval and indicate that the retrieval is sensitive enough to detect mesospheric HO2 layers during both day and night. This new dataset is the first long-term HO2 stratospheric and mesospheric satellite record and it provides needed constraints to help resolve the O3 deficit problem and the "HOx dilemma".

  14. Stratospheric and mesospheric HO2 observations from the Aura Microwave Limb Sounder

    NASA Astrophysics Data System (ADS)

    Millán, L.; Wang, S.; Livesey, N.; Kinnison, D.; Sagawa, H.; Kasai, Y.

    2015-03-01

    This study introduces stratospheric and mesospheric hydroperoxyl radical (HO2) estimates from the Aura Microwave Limb Sounder (MLS) using an offline retrieval (i.e. run separately from the standard MLS algorithm). This new data set provides two daily zonal averages, one during daytime from 10 to 0.0032 hPa (using day-minus-night differences between 10 and 1 hPa to ameliorate systematic biases) and one during nighttime from 1 to 0.0032 hPa. The vertical resolution of this new data set varies from about 4 km at 10 hPa to around 14 km at 0.0032 hPa. A description of the methodology and an error analysis are presented. Comparisons against the Whole Atmosphere Community Climate Model (WACCM), the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) and the Far Infrared Spectrometer (FIRS-2) measurements, as well as photochemical simulations, demonstrate the robustness of the retrieval and indicate that the retrieval is sensitive enough to detect mesospheric HO2 layers during both day and night. This new data set is the first long-term HO2 stratospheric and mesospheric satellite record and it provides needed constraints to help resolve the O3 deficit problem and the "HOx dilemma".

  15. Laser Measurements of the H Atom + Ozone Rate Constant at Mesospheric Temperatures.

    PubMed

    Liu, Yingdi; Peng, Jian; Reppert, Kelsey; Callahan, Sara; Smith, Gregory P

    2016-06-01

    The exothermic H + O3 reaction produces OH(v) Meinel band emissions, used to derive mesospheric H concentrations and chemical heating rates. We remeasured its rate constant to reduce its uncertainty and extended the measurements to lower mesospheric temperatures using modern laser-induced fluorescence (LIF) techniques. H atoms were produced by pulsed ultraviolet laser trace photolysis of O3, followed by reaction of O((1)D) with added H2. A second, delayed, frequency-mixed dye laser measured the reaction decay rate with the remaining ozone using LIF. We monitored either the H atom decay by two photon excitation at 205 nm and detection of red fluorescence, or the OH (v = 9) product time evolution with excitation of the B(2)Σ(+)-X(2)Π (0,9) band at 237 nm and emission in the blue B(2)Σ(+)-A(2)Σ(+) (0,7) band. By cooling the enclosed low pressure flow cell we obtained measurements from 140 to 305 K at 20 to 200 Torr in Ar. Small kinetic modeling corrections were made for secondary regeneration of H atoms. The results are consistent with the current NASA JPL recommendation for this rate constant and establish its extrapolation down to the lower temperatures of the mesosphere. PMID:27193050

  16. New measurements of mesospheric temperature and gravity waves over the Andes mountains

    NASA Astrophysics Data System (ADS)

    Taylor, Michael J.; Pautet, Pierre-Dominique; Pendleton, William R., Jr.; Zhao, Yucheng; Pugmire, Jonathan

    The development of the Andes Lidar Observatory (ALO) at Cerro Pachon, Chile (30° S), is a joint National Science Foundation and University of Illinois research program designed to enable high-quality coordinated studies of the mesospheric lower thermosphere (MLT) region over the Andes mountains. The observatory was completed in August 2009 and a range of in-strumentation including the University of Illinois wind temperature lidar, meteor radar, all-sky OH imager, the Aerospace IR imager and the Utah State University Mesospheric Tempera-ture Mapper (MTM) are currently operational. The observing conditions at Cerro Pachon are excellent, enabling high-quality atmospheric measurements of the MLT dynamics. The MTM obtains sequential observations of selected emissions in the OH (6,2) band and the O2 (0,1) band centered at 87 and 94 km, respectively, to quantify gravity wave structures and mesospheric temperature variability. This presentation focuses on our initial OH and O2 temperature and intensity measurements obtained during the first 10 months of operations. The results are compared with prior MTM measurements from Maui, HI (20° N) (2001-2006) and from Starfire Optical Range, NM (35° N) (1998-1999), to help assess dynamical variability over the Andes mountains under different forcing.

  17. On the mean meridional mass motions of the stratosphere and mesosphere

    NASA Technical Reports Server (NTRS)

    Dunkerton, T.

    1978-01-01

    Using a simplified, approximate 'Lagrangian-mean' dynamical formulation, the mean meridional mass circulation of the stratosphere and mesosphere is discussed. Under solstice conditions, it is shown that this Lagrangian-mean circulation may be inferred, as a first approximation, from the Eulerian-mean diabatic heating. Diabatic heating rates for the solstices, originally derived by Murgatroyd and Goody (1958), result in Lagrangian-mean rising motion at the tropical tropopause, subsidence across the extra-tropical tropopause, and a very strong summer-to-winter pole flow in the mesosphere. This circulation is exactly that obtained by Murgatroyd and Singleton (1961) for the solstices. Those authors, however, attempted to identify this circulation as the Eulerian-mean motion, and were later criticized for their neglect of the meridional eddy heat flux in the calculation, which proved to be extremely important in the winter hemisphere. The present study, nevertheless, indicates that Murgatroyd and Singleton's circulation may in fact be representative of actual air parcel motions in the stratosphere and mesosphere.

  18. Comparison of mesospheric VHF radar echoes and rocket probe electron concentration measurements

    NASA Technical Reports Server (NTRS)

    Royrvik, O.; Smith, L. G.

    1984-01-01

    Refractive index irregularities in the equatorial mesosphere have been investigated using both the Jicamarca VHF radar and a rocket-borne Langmuir probe launched from Punta Lobos, Peru. On February 27, 1983, a single layer of turbulence was observed in the upper mesosphere by both experiments. There is very good agreement between the observed radar echo power and the radar scattering cross section calculated from the rocket data when these are interpreted in the context of isotropic turbulence. The inner and outer scales of turbulence have been calculated from both the radar and the rocket data, and good agreement is found. The radar data show indications of large-scale vortices in the layer of irregularities. Rocket data show that the inner scale of turbulence in the upper mesosphere is a few tens of meters and that the Jicamarca radar Bragg wavelength (3 m) is well within the viscous subrange of turbulence in this altitude range. The spectral index in the inertial subrange is close to -5/3, changing to about - 7 at higher wave numbers. Energy dissipation rate in the layer was calculated to be 0.05 W/kg, in good agreement with previous estimates.

  19. Odin observations of Antarctic nighttime NO densities in the mesosphere-lower thermosphere and observations of a lower NO layer

    NASA Astrophysics Data System (ADS)

    Sheese, P. E.; Strong, K.; Gattinger, R. L.; Llewellyn, E. J.; Urban, J.; Boone, C. D.; Smith, A. K.

    2013-07-01

    The Optical Spectrograph and Infrared Imaging System (OSIRIS) on the Odin satellite currently has an eight-year dataset of nighttime Antarctic nitric oxide densities, [NO], in the mesosphere-lower thermosphere (MLT) region. In this work, the OSIRIS data are compared with a similar data set from the Sub-Millimeter Radiometer (SMR), also on the Odin satellite. Both of the Odin data sets are compared with twilight [NO] from the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) on the SciSat-I satellite. Direct comparisons of OSIRIS and SMR profiles show large differences, indicating that the individual [NO] profiles of one or both data sets may not be valid. However, when comparing averaged [NO], variations on timescales of weeks-years in all three data sets are in good agreement and correspond to the 27 day and 11 year solar cycles. The averaged OSIRIS values are typically 10% greater than SMR and 30% greater than ACE-FTS, which are within the estimated OSIRIS systematic uncertainties. These results suggest that the satellite-derived data sets can be used for determining polar-mean NO climatology and variations on timescales of weeks-years. The OSIRIS and SMR nighttime data sets show that the [NO] peak height in the MLT decreases throughout the autumn, from an altitude near or above 100 km to a minimum altitude ranging from 90 to 95 km around winter solstice. A similar decrease in [NO] peak height is observed in modeled NO climatology from the Specified Dynamics-Whole Atmosphere Community Climate Model (SD-WACCM), although the SD-WACCM climatology exhibits a decrease throughout autumn from 107 km down to 102 km. The results suggest that global climate models require more sophisticated auroral forcing simulations in order to reproduce observed NO variations in this region.

  20. Retrieval of sodium number density profiles in the mesosphere and lower thermosphere from SCIAMACHY limb emission measurements

    NASA Astrophysics Data System (ADS)

    Langowski, M. P.; von Savigny, C.; Burrows, J. P.; Rozanov, V. V.; Dunker, T.; Hoppe, U.-P.; Sinnhuber, M.; Aikin, A. C.

    2016-01-01

    An algorithm has been developed for the retrieval of sodium atom (Na) number density on a latitude and altitude grid from SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) limb measurements of the Na resonance fluorescence. The results are obtained between 50 and 150 km altitude and the resulting global seasonal variations of Na are analyzed. The retrieval approach is adapted from that used for the retrieval of magnesium atom (Mg) and magnesium ion (Mg+) number density profiles recently reported by Langowski et al. (2014). Monthly mean values of Na are presented as a function of altitude and latitude. This data set was retrieved from the 4 years of spectroscopic limb data of the SCIAMACHY mesosphere and lower thermosphere (MLT) measurement mode (mid-2008 to early 2012). The Na layer has a nearly constant peak altitude of 90-93 km for all latitudes and seasons, and has a full width at half maximum of 5-15 km. Small but significant seasonal variations in Na are identified for latitudes less than 40°, where the maximum Na number densities are 3000-4000 atoms cm-3. At middle to high latitudes a clear seasonal variation with a winter maximum of up to 6000 atoms cm-3 is observed. The high latitudes, which are only measured in the summer hemisphere, have lower number densities, with peak densities being approximately 1000 Na atoms cm-3. The full width at half maximum of the peak varies strongly at high latitudes and is 5 km near the polar summer mesopause, while it exceeds 10 km at lower latitudes. In summer the Na atom concentration at high latitudes and at altitudes below 88 km is significantly smaller than that at middle latitudes. The results are compared with other observations and models and there is overall a good agreement with these.

  1. Strato-mesospheric ClO observations by SMILES: error analysis and diurnal variation

    NASA Astrophysics Data System (ADS)

    Sato, T. O.; Sagawa, H.; Kreyling, D.; Manabe, T.; Ochiai, S.; Kikuchi, K.; Baron, P.; Mendrok, J.; Urban, J.; Murtagh, D.; Yasui, M.; Kasai, Y.

    2012-07-01

    Chlorine monoxide (ClO) is the key species for anthropogenic ozone loss in the middle atmosphere. We observed the ClO diurnal variation using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station which has a non sun-synchronous orbit. This is the first global observation of the ClO diurnal variation from the stratosphere up to the mesosphere. The SMILES observation reproduced the diurnal variation of stratospheric ClO, an enhancement during a daytime, as observed by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite (UARS/MLS). Mesospheric ClO has shown a different diurnal behavior with an enhancement during nighttime. The ClO enhancement was found at a pressure of 0.02 hPa (about 70 km) with an amplitude of about 100 pptv and reached up to 0.01 hPa (80 km) in the zonal mean of 50° N-65° N in January-February 2010. The observation of mesospheric ClO was possible due to the 10-20 times better signal-to-noise ratio of the spectra than those of past microwave/submillimeter-wave limb-emission sounders. We performed a quantitative error analysis for the strato- and mesospheric ClO of the Level-2 research (L2r) product version 2.1.5 taking into account all possible error contributions; i.e. errors due to spectrum noise, smoothing and uncertainties in the radiative transfer model and instrument function. The SMILES L2r v2.1.5 ClO data are useful over the range 0.01 and 100 hPa with a total error of 10-30 pptv (about 10%) with averaging of 100 profiles. The vertical resolution is 3-5 km and 5-8 km for the stratosphere and mesosphere, respectively. The performance of the SMILES observation opens the new opportunity to investigate ClO up to the mesopause.

  2. Strato-mesospheric ClO observations by SMILES: error analysis and diurnal variation

    NASA Astrophysics Data System (ADS)

    Sato, T. O.; Sagawa, H.; Kreyling, D.; Manabe, T.; Ochiai, S.; Kikuchi, K.; Baron, P.; Mendrok, J.; Urban, J.; Murtagh, D.; Yasui, M.; Kasai, Y.

    2012-11-01

    Chlorine monoxide (ClO) is the key species for anthropogenic ozone losses in the middle atmosphere. We observed ClO diurnal variations using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station, which has a non-sun-synchronous orbit. This includes the first global observations of the ClO diurnal variation from the stratosphere up to the mesosphere. The observation of mesospheric ClO was possible due to 10-20 times better signal-to-noise (S/N) ratio of the spectra than those of past or ongoing microwave/submillimeter-wave limb-emission sounders. We performed a quantitative error analysis for the strato- and mesospheric ClO from the Level-2 research (L2r) product version 2.1.5 taking into account all possible contributions of errors, i.e. errors due to spectrum noise, smoothing, and uncertainties in radiative transfer model and instrument functions. The SMILES L2r v2.1.5 ClO data are useful over the range from 0.01 and 100 hPa with a total error estimate of 10-30 pptv (about 10%) with averaging 100 profiles. The SMILES ClO vertical resolution is 3-5 km and 5-8 km for the stratosphere and mesosphere, respectively. The SMILES observations reproduced the diurnal variation of stratospheric ClO, with peak values at midday, observed previously by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite (UARS/MLS). Mesospheric ClO demonstrated an opposite diurnal behavior, with nighttime values being larger than daytime values. A ClO enhancement of about 100 pptv was observed at 0.02 to 0.01 hPa (about 70-80 km) for 50° N-65° N from January-February 2010. The performance of SMILES ClO observations opens up new opportunities to investigate ClO up to the mesopause.

  3. Detection of meteoric smoke particles in the mesosphere by a rocket-borne mass spectrometer

    NASA Astrophysics Data System (ADS)

    Robertson, Scott; Dickson, Shannon; Horányi, Mihaly; Sternovsky, Zoltan; Friedrich, Martin; Janches, Diego; Megner, Linda; Williams, Bifford

    2014-10-01

    In October 2011, two CHAMPS (Charge And Mass of meteoric smoke ParticleS) sounding rockets were launched into the polar mesosphere, each carrying an electrostatic multichannel mass analyzer for charged meteoric smoke particles (MSPs) that operated from 60 to 100 km and returned data on the number density of the charged MSPs in several ranges of mass. The payloads also carried Faraday rotation antennas and an array of plasma probes for determining electron and ion densities and the payload charging potential, thus providing a comprehensive picture of the distribution of charges over a wide range of altitudes that can be compared with models for the vertical distribution of MSPs and for the distribution of charge. The launches were from the Andøya Rocket Range, Norway, following the end of the noctilucent cloud season to avoid detection of ice. A night launch (11 October 21:50 UT) and a day launch (13 October 13:50 UT) helped to elucidate the role of solar ultraviolet in determining the charge state of the particles. The night data show a distinct change in the charge state of MSPs at the D-region ledge (~78 km) below which the density of free electrons is greatly reduced. Above the ledge, negative MSPs are detected at up to 92 km, have number densities reaching ~200 cm-3, and positive MSPs are absent. Below the ledge, positive and negative MSPs are about equally abundant, each with densities of ~2000 cm-3 at 70 km and with slightly lower densities at 60 km. The MSPs are seen predominantly in mass bins spanning 500-2000 amu and 2000-8000 amu, with more massive particles (radii above ~1.2 nm assuming a smoke particle density of 2 g/cm3) having number densities below the detection threshold (10 cm-3) and less massive particles being indistinguishable from ions. The daytime launch data show positive MSPs present only below the ledge and their number density is reduced to below 300 cm-3. The daytime data show negative MSPs both above and below the D-region ledge and

  4. Comparisons of Na densities, Fe densities, and temperature measured over south polar cap with model predictions

    NASA Astrophysics Data System (ADS)

    Chu, X.; Gardner, C. S.; Vondrak, T.; Murray, B.; Plane, J. M.; Roble, R. G.; Espy, P. J.; Kawahara, T.

    Mesospheric Na and Fe layer densities and temperatures were measured by lidar systems at the South Pole, Syowa (69S, 39E), and Rothera (67.5S, 68.0W) during the past several years. Comparison of the wintertime temperatures measured above these sites with TIME-GCM predictions, suggests that the model over-estimates the compressional heating associated with downwelling. When simulating the winter Na and Fe densities at the pole using the UEA 1-D chemistry models, a 2-D general circulation model SOCRATES was used to predict the meridional and downward vertical transportation of O, H, etc. from the sunlit lower latitude into the polar vortex. However, the simulation indicates that the circulation, especially downward transport into the polar vortex, is overestimated by the general circulation model. Thus, the wintertime Na layer nearly disappears in the chemistry model, which does not agree with the maximum Na abundance observed in winter. In summer, the model correctly predicts the observed depletion of the metal atoms below 90 km. This results from the uptake of the metals onto ice particles, which seem to be a persistent feature of the summertime upper mesosphere at high latitudes. This paper will show that the observed seasonal behavior of the metal layers provides a rigorous test of general circulation models in the upper mesosphere.

  5. Polarization developments

    SciTech Connect

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist.

  6. Neuronal polarization.

    PubMed

    Takano, Tetsuya; Xu, Chundi; Funahashi, Yasuhiro; Namba, Takashi; Kaibuchi, Kozo

    2015-06-15

    Neurons are highly polarized cells with structurally and functionally distinct processes called axons and dendrites. This polarization underlies the directional flow of information in the central nervous system, so the establishment and maintenance of neuronal polarization is crucial for correct development and function. Great progress in our understanding of how neurons establish their polarity has been made through the use of cultured hippocampal neurons, while recent technological advances have enabled in vivo analysis of axon specification and elongation. This short review and accompanying poster highlight recent advances in this fascinating field, with an emphasis on the signaling mechanisms underlying axon and dendrite specification in vitro and in vivo. PMID:26081570

  7. Polarization Aberrations

    NASA Technical Reports Server (NTRS)

    Mcguire, James P., Jr.; Chipman, Russell A.

    1990-01-01

    The analysis of the polarization characteristics displayed by optical systems can be divided into two categories: geometrical and physical. Geometrical analysis calculates the change in polarization of a wavefront between pupils in an optical instrument. Physical analysis propagates the polarized fields wherever the geometrical analysis is not valid, i.e., near the edges of stops, near images, in anisotropic media, etc. Polarization aberration theory provides a starting point for geometrical design and facilitates subsequent optimization. The polarization aberrations described arise from differences in the transmitted (or reflected) amplitudes and phases at interfaces. The polarization aberration matrix (PAM) is calculated for isotropic rotationally symmetric systems through fourth order and includes the interface phase, amplitude, linear diattenuation, and linear retardance aberrations. The exponential form of Jones matrices used are discussed. The PAM in Jones matrix is introduced. The exact calculation of polarization aberrations through polarization ray tracing is described. The report is divided into three sections: I. Rotationally Symmetric Optical Systems; II. Tilted and Decentered Optical Systems; and Polarization Analysis of LIDARs.

  8. Lidar Observations and Numerical Modeling Studies of Thermospheric Metal Layers and Solar Effects on Mesospheric Fe Layers

    NASA Astrophysics Data System (ADS)

    Yu, Zhibin

    By blocking extreme hazards from space and regulating radio wave propagation, the space-atmosphere interaction region (SAIR) -- our window to open space -- is essential for life on Earth and modern society. However, the physical and chemical processes governing the SAIR are not sufficiently understood due to the woefully incomplete measurements of neutral properties in this region, especially between 100 and 200 km altitude. Thermospheric Fe layers extending from ~70 to 170 km discovered by the Fe Boltzmann lidar at McMurdo, Antarctica have opened a new door to observing the neutral thermosphere and mesosphere. This thesis is aimed at revealing such new discoveries, and advancing our understanding of the thermospheric Fe layer formation, through analyzing the lidar data collected by the author in Antarctic winter and developing the first thermospheric Fe/Fe+ model. A one-dimensional high-latitude Fe/Fe+ model based on physical and chemical first principles has been developed to quantitatively explore the source, formation and evolution of thermospheric Fe layers. We demonstrate that the observed Fe layers are produced by neutralization of converged Fe+, mainly through the direct electron-Fe+ recombination. We find that the polar electric field is capable of uplifting Fe+ ions from the main deposition region into the thermosphere, supplying the source of neutral Fe. Both gravity-wave-induced wind shears and the polar electric field can converge Fe+ layers. Vertical wind plays a key role in transporting Fe to form the observed wave structures, but horizontal divergence can largely offset the vertical convergence effects. These theoretical studies lay the foundation for exploring the thermosphere by resonance lidars. The diurnal variations of Fe layers in the mesopause region are characterized with our lidar observations at McMurdo. A new finding is the solar effect on the Fe layer bottomside --- daytime downward extension and nighttime upward contraction. We explain

  9. Lidar probing of the mesosphere: Simultaneous observations of sporadic sodium and iron formations, calcium ion layers, neutral temperature and winds

    NASA Astrophysics Data System (ADS)

    Kane, Timothy J.; Qian, Jun; Scherrer, Daniel R.; Senft, Daniel C.; Pfenninger, W. Matthew; Papen, George C.; Gardner, Chester S.

    1992-07-01

    Meteoritic ablation in the upper atmosphere is the commonly accepted source of the mesospheric metals between 80 and 105 km. The vertical and temporal behavior of some of these metals can be probed with high accuracy and resolution using resonance fluorescence lidar techniques. Of considerable interest in recent years has been the sporadic and rapid formation of thin, dense enhancements in these metallic layers. Since late Mar. 1991, the UIUC CEDAR lidar system, located at the Urbana Atmospheric Observatory, has been routinely operating at the Fe resonance line of 372 nm in order to probe the mesospheric Fe layer. In Nov. 1991, the capability to investigate mesospheric Ca(+) at the resonance line of 393.4 nm was added. The lidar's eximer-pumped dye laser uses Exciton QUI laser dye dissolved in p-dioxane, which can lase at both the Fe and Ca(+) frequencies. Various aspects of this investigation are discussed.

  10. Polar Bear

    USGS Publications Warehouse

    Amstrup, S.D.; DeMaster

    1988-01-01

    Polar bears are long-lived, late-maturing carnivores that have relatively low rates of reproduction and natural mortality. Their populations are susceptible to disturbance from human activities, such as the exploration and development of mineral resources or hunting. Polar bear populations have been an important renewable resource available to coastal communities throughout the Arctic for thousands of years.

  11. Rocket-borne probes for charged mesospheric aerosol particles

    NASA Astrophysics Data System (ADS)

    Robertson, S.; Horanyi, M.; Sternovsky, Z.

    We describe a series of rocket-borne probes for detecting charged solid particles in the ionosphere. The first type of probe is a flat charge-collecting surface on the skin of the rocket. Behind this surface is a permanent magnet that shields the probe from electrons. The current that is recorded is thus from heavier charged aerosol particles. This heavy charge carrier current is converted to a charge number density. A probe launched from White Sands in November 1998 detected a narrow layer at 86 km consistent with sporadic E layer of metallic ions. Two launches were made from the Andoya Rocket Range (Norway) during the MIDAS SOLSTICE campaign in the summer of 2001. Layers of positively and negatively charged aerosol particles were detected on both flights, but inadvertent positive ion collection complicated the analysis. Subsequent payloads included a second probe that supplemented the magnetic field with a positive bias voltage to improve positive ion rejection. Three launches were made from Andoya during the MIDAS MacWAVE campaign in July 2003 with this dual-probe package. Within PMSE, the probes measured an aerosol particle distribution, clearly resolving small positive, small negative, and large negative particles. A new mass-analyzing probe is being developed in which electric fields within the nosecone deflect charged aerosol particles admitted at the nosecone tip. This probe takes advantage of the reduced density behind the shock front to increase the mean free path within the instrument so that cryopumping is not required. The new probe has three pairs of collection surfaces with opposite polarities for collecting (1) electrons and light ions, (2) particles with mass 150-103 amu, and (3) particles with mass 103 -- 2 x 104 amu.

  12. Polarized rainbow.

    PubMed

    Können, G P; de Boer, J H

    1979-06-15

    The Airy theory of the rainbow is extended to polarized light. For both polarization directions a simple analytic expression is obtained for the intensity distribution as a function of the scattering angle in terms of the Airy function and its derivative. This approach is valid at least down to droplet diameters of 0.3 mm in visible light. The degree of polarization of the rainbow is less than expected from geometrical optics; it increases with droplet size. For a droplet diameter >1 mm the locations of the supernumerary rainbows are equal for both polarization directions, but for a diameter <1 mm the supernumerary rainbows of the weaker polarization component are located between those in the strong component. PMID:20212586

  13. Modeling the microphysics of CO2 ice clouds within wave-induced cold pockets in the martian mesosphere

    NASA Astrophysics Data System (ADS)

    Listowski, C.; Määttänen, A.; Montmessin, F.; Spiga, A.; Lefèvre, F.

    2014-07-01

    Mesospheric CO2 ice clouds on Mars are simulated with a 1D microphysical model, which includes a crystal growth rate adapted to high supersaturations encountered in the martian mesosphere. Observational constraints (crystal radius and opacity) exist for these clouds observed during the day around the equator at ∼60-80 km altitude. Nighttime mesospheric clouds interpreted as CO2 ice clouds have also been characterized at low southern latitudes, at ∼90-100 km altitude. From modeling and observational evidence, it is believed that mesospheric clouds are formed within temperature minima created by thermal tides, where gravity wave propagation allows for the creation of supersaturated layers (cold pockets). Thus, temperature profiles perturbed by gravity waves are used in the model to initiate nucleation and maintain growth of CO2 ice crystals. We show that it is possible to reproduce the observed effective radii for daytime and nighttime clouds. Crystal sizes are mainly governed by the altitude where the cloud forms, and by the amplitude of supersaturation. The temporal and spatial behavior of the cloud is controlled by the extent and lifetime of the cold pocket. The cloud evaporates fast after the cold pocket has vanished, implying a strong correlation between gravity wave activity and CO2 cloud formation. Simulated opacities remain far below the observed ones as long as typical dust conditions are used. In the case of the lower daytime clouds, the enhanced mesospheric dust loading typically reached during dust storm conditions, allows for greater cloud opacities, close to observed values, by supplying the atmosphere with condensation nuclei. However, CO2 ice clouds are not detected during the dust storm season, and, because of fast sedimentation of dust particles, an exogenous supply (meteoritic flux) appears necessary to explain opacities of both daytime and nighttime mesospheric CO2 ice clouds along their whole period of observation.

  14. Response of the mesosphere to human-induced perturbations and solar variability calculated by a 2-D model

    NASA Astrophysics Data System (ADS)

    Khosravi, Rashid; Brasseur, Guy; Smith, Anne; Rusch, David; Walters, Stacy; Chabrillat, Simon; Kockarts, Gaston

    2002-09-01

    We have used the improved NCAR interactive 2-D model (SOCRATES) to investigate the chemical and thermal response of the mesosphere to composition changes from the preindustrial era (˜1850) to the present, to doubling the CO2 concentration, and to the 11-year solar flux variability. The calculations show that all regions in the model mesosphere have cooled relative to the preindustrial times. The mesopause region has cooled by ˜5 K and the winter pole by up to 9 K near 60 km. Ozone mixing ratio has decreased by about 5% in the lower mesosphere and by about 30% near the summer mesopause region (caused by a dramatic increase in [OH]). Doubling the CO2 abundance cools the whole mesosphere by about 4-16 K and has a complicated effect on O3, which exhibits an alternating increase/decrease behavior from the lower mesosphere up to the mesopause region. Similar results are obtained, in both magnitude and structure, for the O3 response to a decrease in solar UV flux. Similarities are also found in the response of T, OH, and H to these two perturbations. These results lead to the conclusion that the long-term increase in the well-mixed greenhouse gases, in particular CO2, alters the thermal structure and chemical composition of the mesosphere significantly and that these anthropogenic effects are of the same magnitude as the effects associated with the 11-year solar cycle. Thus, the difference in the timescales involved suggests that the anthropogenic signal over periods of typically 10 years is smaller than the signal generated by the 11-year solar variability. Finally, analysis of the results from a simulation of the combined perturbations (2 × CO2 + 11-year solar variability) shows that, for the most part, the solar variability does not interact with increasing CO2 and vice versa; that is, the two effects are additive.

  15. Measurements of mesospheric water vapour, aerosols and temperatures with the Spectral Absorption Line Imager (SALI-AT)

    NASA Astrophysics Data System (ADS)

    Shepherd, M. G.; Mullins, M.; Brown, S.; Sargoytchev, S. I.

    2001-08-01

    Water vapour concentration is one of the most important, yet one of the least known quantities of the mesosphere. Knowledge of water vapour concentration is the key to understanding many mesospheric processes, including the one that is primary focus of our investigation, mesospheric clouds (MC). The processes of formation and occurrence parameters of MC constitute an interesting problem in their own right, but recently evidence has been provided which suggests that they are a critical indicator of atmospheric change. The aim of the SALI-AT experiment is to make simultaneous (although not strictly collocated) measurements of water vapour, aerosols and temperature in the mesosphere and the mesopause region under twilight condition in the presence of mesospheric clouds. The water vapour will be measured in the regime of solar occultation utilizing a water vapour absorption band at 936 nm wavelength employing the SALI (Spectral Absorption Line Imager) instrument concept. A three-channel zenith photometer, AT-3, with wavelengths of 385 nm, 525 nm, and 1040 nm will measure Mie and Rayleigh scattering giving both mesospheric temperature profiles and the particle size distribution. Both instruments are small, low cost and low mass. It is envisioned that the SALI-AT experiment be flown on a small rocket - the Improved Orion/Hotel payload configuration, from the Andoya Rocket range, Norway. Alternatively the instrument can be flown as a "passenger" on larger rocket carrying other experiments. In either case flight costs are relatively low. Some performance simulations are presented showing that the instrument we have designed will be sufficiently sensitive to measure water vapor in concentrations that are expected at the summer mesopause, about 85 km height.

  16. Mesospheric turbulence detection and characterization with AMISR-class radars under consistent meteorological conditions

    NASA Astrophysics Data System (ADS)

    Li, J.; Collins, R. L.; Newman, D.; Nicolls, M. J.; Varney, R. H.; Thurairajah, B.

    2015-12-01

    A recent study has shown the ability of the Advanced Modular Incoherent Scatter Radar (AMISR) at Poker Flat Research Range (PFRR, PFISR) to characterize turbulence in the mesosphere (D-Region) [Nicolls et. al, 2011]. We present case studies of AMISR measurements of turbulence where the meteorological conditions are defined by the presence of persistent Mesospheric Inversion Layers (MILs). We consider MILs that are detected by satellite over a day and are also detected by Rayleigh lidar at PFRR [Irving et. al, 2014]. MILs are a signature of large-scale planetary wave breaking in the upper atmosphere, where a region with a temperature inversion lies below a region with an adiabatic lapse rate. The region with the inversion allows small-scale waves to become unstable, break, and generate turbulence. The region with the adiabatic lapse rate is indicative of a well-mixed layer and the presence of turbulence. AMISR-class radars have a steerable narrow beam (1°) and high vertical resolution (750 m). We review the principles and practices of incoherent scatter radar with a focus on detection of D-region turbulence using radar spectra. We present the geometry of the turbulence and the radar, comparing the turbulent, plasma, and radar spatial scales. We develop a turbulence retrieval algorithm using a Voigt function spectral line. We fit the spectra to a Voigt function using the Levenberg-Marquardt method and use the Gaussian component of the Voigt spectra to calculate the RMS velocity, and hence the turbulent energy dissipation rate. With the environmental conditions characterized by satellite and lidar and the turbulence characterized by radar data, we can test the ability of PFISR to characterize mesospheric turbulence under consistent meteorological conditions and develop robust technique for turbulence measurements.

  17. Characteristics of mesospheric gravity waves near the magnetic equator, Brazil, during the SpreadFEx campaign

    NASA Astrophysics Data System (ADS)

    Taylor, M. J.; Pautet, P.-D.; Medeiros, A. F.; Buriti, R.; Fechine, J.; Fritts, D. C.; Vadas, S. L.; Takahashi, H.; São Sabbas, F. T.

    2009-02-01

    As part of the SpreadFEx campaign, coordinated optical and radio measurements were made from Brazil to investigate the occurrence and properties of equatorial Spread F, and to characterize the regional mesospheric gravity wave field. All-sky image measurements were made from two sites: Brasilia and Cariri located ~10° S of the magnetic equator and separated by ~1500 km. In particular, the observations from Brasilia provided key data in relatively close proximity to expected convective sources of the gravity waves. High-quality image measurements of the mesospheric OH emission and the thermospheric OI (630 nm) emission were made during two consecutive new moon periods (22 September to 9 November 2005) providing extensive data on the occurrence and properties of F-region depletions and regional measurements of the dominant gravity wave characteristics at each site. A total of 120 wave displays were observed, comprising 94 short-period events and 26 medium-scale gravity waves. The characteristics of the small-scale waves agreed well with previous gravity wave studies from Brazil and other sites. However, significant differences in the wave propagation headings indicate dissimilar source regions for the Brasilia and Cariri datasets. The observed medium-scale gravity wave events constitute an important new dataset to study their mesospheric properties at equatorial latitudes. These data exhibited similar propagation headings to the short-period events, suggesting they originated from the same source regions. Medium-scale waves are generally less susceptible to wind filtering effects and modeling studies utilizing these data have successfully identified localized regions of strong convection, mainly to the west of Brasilia, as their most likely sources (Vadas et al., 2009).

  18. Lightning Interaction with the Lower Ionosphere: Effects of Mesospheric Ions and Geomagnetic Field

    NASA Astrophysics Data System (ADS)

    Marshall, R. A.; Inan, U. S.

    2011-12-01

    The interaction between the lightning electromagnetic pulse (EMP) and quasi-electrostatic (QE) fields and the D-region ionosphere has been observed optically in the past 20 years through sprites, elves, and gigantic jets. Very-low-frequency (VLF) measurements have been used to measure direct ionospheric modification, which may comprise electron density changes and/or heating. In the same time period, a number of models have been used to study the lightning-ionosphere interaction. Here, we present new time-domain 2D and 3D models of the lightning-ionosphere interaction, including EMP and QE effects. These spherical-coordinate models include effects of Earth's magnetic field; effects of mesospheric and ionospheric electron and ion densities; and responses to arbitrary lightning amplitudes, waveforms, and orientations. In this paper, we use the new models to investigate the response of the ionosphere under varying conditions. First, we focus on the effects of different mesospheric ion density profiles. Mesospheric ions, for which measurements are nearly nonexistent, serve to reduce the amplitude of the electromagnetic pulse as it propagates towards the ionosphere; high ion densities will reduce the wave electric field enough that it does not exceed the breakdown field in the ionosphere. We demonstrate the relationship between the lightning parameters, ion density profile, and observed elve intensity, and show that elves are suppressed when the ion density is high. Second, we investigate the effects of the geomagnetic field magnitude and orientation on wave propagation in and through the ionosphere. We compare these simulation results with known global lightning distributions and compare to the observed whistler distributions onboard satellites.

  19. Model Studies of Electrical Coupling Processes in Equatorial Mesosphere and Lower Ionosphere

    NASA Astrophysics Data System (ADS)

    Tonev, Peter; Velinov, Peter

    2016-07-01

    The quasi-electrostatic response of equatorial lower ionosphere and mesosphere to forcing from below by electrical sources located in the troposphere (e.g. thunderclouds) or at surface (e.g. related to earthquakes) is studied. Such sources generate quasi-static (QS) electric fields in the lower ionosphere and mesosphere which can be large enough in nighttime conditions to cause electron heating, modifications of conductivity and electron density, etc. We demonstrate that this response to the forcing from below highly depends on the geomagnetic latitude determining the magnetic field lines inclination, and thus, the tensor of anisotropic conductivity. Our previous results show that the QS electric fields in the lower nighttime ionosphere above tropospheric sources are much bigger and have larger horizontal extension than those generated at high latitudes by otherwise same conditions. Now we estimate by modeling the electric currents and fields generated at equatorial latitudes in lower ionosphere and mesosphere above electrical charges located in the troposphere or at ground which can have different horizontal dimensions during quiet periods and of their self-consistent effects to electron heating and conductivity. Specific configurations of electric currents and distributions of related electric fields are estimated first by constant (ambient) conductivity. Then, these are evaluated self-consistently with conductivity modification. The electric currents are re-oriented above ~85 km and flow in a narrow horizontal layer where they dense. Respectively, the electric fields and their effect on conductivity have much larger horizontal scale than at middle latitudes (few hundred of kilometers). Sources of large horizontal dimensions, such as mesoscale convective structures and complexes or earthquakes, cause enhancements of electric fields and their effects due to superposition of horizontally reoriented electric currents well above 70 km. In case of thunderstorms these

  20. Causative Mechanisms of Tropical (10°N-15°N) Mesospheric Inversion Layers

    NASA Astrophysics Data System (ADS)

    Ramesh, Karanam; Sundararajan, Sridharan; Vijaya Bhaskara Rao, S.

    2016-07-01

    The inversion of temperature gradient from negative to positive superimposed upon the characteristically decreasing mesospheric thermal structure is known as Mesospheric Inversion Layer (MIL). Gravity wave breaking, planetary wave critical level interaction and the chemical heating have been suggested as potential causative mechanisms for the occurrence of the MILs. Although the morphological characteristics of MIL have been studied in detail at different sites using various instrumental techniques, their causative mechanisms are still unknown. In the present study, nearly all these major causative mechanisms have been addressed through a few case studies observed from Rayleigh lidar and TIMED-SABER (Thermosphere Ionosphere Mesosphere Energetics and Dynamics - Sounding of Atmosphere by Broadband Emission Radiometry) nightly temperatures over a tropical site, Gadanki (13.5°N,79.2°E). A few large MILs are observed above ˜80 km with amplitude and thickness of ˜50 K and ˜5 km respectively in 2007 and 2011 which are found to be predominantly due to gravity wave breaking and large chemical heating rate (˜15 K/day) by the exothermic reaction, H+O _{3}->OH+O _{2} respectively. It is also found that the SABER shows larger ozone (O _{3}) mixing ratios at the inversion heights (˜80-85 km) during the MIL events in 2011. In another special case study, a triple layered MIL event with three inversion layers at ˜70 km (˜11 K), 80 km (˜44 K), 90 km (˜109 K) has been observed in September 2011 over Gadanki region. It is found that these three inversion layers are respectively due to planetary wave breaking, gravity wave tidal interaction and chemical heating by the reaction, O+O+M->O _{2}+M.

  1. Gravity wave coupling between the mesosphere and thermosphere over New Zealand

    NASA Astrophysics Data System (ADS)

    Smith, S. M.; Vadas, S. L.; Baggaley, W. J.; Hernandez, G.; Baumgardner, J.

    2013-05-01

    images obtained with the Boston University all-sky imaging system located at the Mount John University Observatory, New Zealand (43.98°S, 170.42°E) show clear evidence of dynamic coupling between the mesosphere and thermosphere. Gravity wave (GW) breaking events in the upper mesosphere at altitudes (z) of 80 to 100 km were observed in the 557.7 nm emission on the evening of 4 March 2009 from 08:40 to 13:50 UT. During this time, unusual oppositely propagating weak northwestward (NW-ward) and strong southeastward (SE-ward) GWs were observed in the all-sky images of the thermospheric atomic oxygen O(1D) 630.0 nm emission at 250 km altitude. The waves appeared to originate from the same location over New Zealand, with phase fronts nearly parallel to the landmass axis of the South Island of New Zealand. Additionally, the southern portion of the wave train ends abruptly at the southern tip of New Zealand. The SE-ward GWs were stronger and appeared for ~5 h, while the NW-ward GWs were weaker and only appeared for ~1.75 h. We provide evidence that mountain waves were likely generated in the troposphere that evening. Momentum deposition from GW breaking excites secondary GWs. We model these secondary GWs and show that these GWs have a similar morphology and behavior as observed. Wind filtering in the thermosphere can account for the larger amplitudes and persistent appearance of the SE-ward GWs and the smaller amplitudes and less persistent appearance of the NW-ward GWs. Thus, the morphology and behavior of the 630.0 nm GWs suggest that they were secondary GWs generated from mountain wave breaking in the upper mesosphere. We also show that similar SE-ward GWs have occurred in the 630.0 nm emission on other occasions.

  2. Mesospheric airglow and ionospheric responses to upward-propagating acoustic and gravity waves above tropospheric sources

    NASA Astrophysics Data System (ADS)

    Snively, J. B.; Zettergren, M. D.

    2013-12-01

    The existence of acoustic waves (periods ~1-5 minutes) and gravity waves (periods >4 minutes) in the ionosphere above active tropospheric convection has been appreciated for more than forty years [e.g., Georges, Rev. Geophys. and Space Phys., 11(3), 1973]. Likewise, gravity waves exhibiting cylindrical symmetry and curvature of phase fronts have been observed via imaging of the mesospheric airglow layers [e.g., Yue et al., JGR, 118(8), 2013], clearly associated with tropospheric convection; gravity wave signatures have also recently been detected above convection in ionospheric total electron content (TEC) measurements [Lay et al., GRL, 40, 2013]. We here investigate the observable features of acoustic waves, and their relationship to upward-propagating gravity waves generated by the same sources, as they arrive in the mesosphere, lower-thermosphere, and ionosphere (MLTI). Numerical simulations using a nonlinear, cylindrically-axisymmetric, compressible atmospheric dynamics model confirm that acoustic waves generated by transient tropospheric sources may produce "concentric ring" signatures in the mesospheric hydroxyl airglow layer that precede the arrival of gravity waves. As amplitudes increase with altitude and decreasing neutral density, the modeled acoustic waves achieve temperature and vertical wind perturbations on the order of ~10s of Kelvin and m/s throughout the E- and F-region. Using a coupled multi-fluid ionospheric model [Zettergren and Semeter, JGR, 117(A6), 2012], extended for low-latitudes using a 2D dipole magnetic field coordinate system, we investigate acoustic wave perturbations to the ionosphere in the meridional direction. Resulting perturbations are predicted to be detectable by ground-based radar and GPS TEC measurements, or via in situ instrumentation. Although transient and short-lived, the acoustic waves' airglow and ionospheric signatures are likely to in some cases be observable, and may provide important insight into the regional

  3. Thermal structure and minor species distribution of Venus mesosphere by ALMA submm observations

    NASA Astrophysics Data System (ADS)

    Piccialli, Arianna; Moreno, Raphael; Encrenaz, Therese; Fouchet, Thierry; Lellouch, Emmanuel; Moullet, Arielle; Widemann, Thomas

    2015-11-01

    Venus upper atmosphere (70-150 km altitude) is a transition region characterized by a complex dynamics: strong retrograde zonal winds dominate the lower mesosphere while a solar-to-antisolar circulation is observed in the upper mesosphere/lower thermosphere. In addition, photochemical processes play an important role at these altitudes and affect the thermal structure and chemical stability of the entire atmosphere. Sulfur dioxide and water vapor are key species in the photochemical cycles taking place in the troposphere and mesosphere of Venus. They are carried by convective transport, together with the Hadley circulation, up to about 60 km where SO2 is photodissociated and oxydated, leading to the formation of H2SO4 which condenses in the clouds enshrouding the planet. Previous observations obtained by several instruments on board Venus Express and during ground-based campaigns have shown evidence of strong temporal variations, both on day-to-day as well as longer timescales, of density, temperature and SO2 abundance. Such strong variability is still not well understood.Submillimeter observations obtained with the Atacama Large Millimeter Array (ALMA) offer the possibility of probing Venus upper mesosphere and of monitoring minor species, winds and the thermal structure. A first set of observations was obtained on November 14, 15, 26 and 27, 2011 during the first ALMA Early Science observation cycle. These observations targeted SO2, SO, HDO and CO transitions around 345 GHz during four sequences of 30 minutes each. The Venus’ disk was about 11” with an illumination factor of 90%, so that mostly the dayside of the planet was mapped.Assuming nominal night-time and dayside CO abundance profiles from Clancy et al. 2013, we retrieved vertical temperature profiles over the entire disk as a function of latitude and local time for the four days of observation. Temperature profiles were later used to derive the abundances of minor species (HDO, SO, SO2) in each pixel

  4. Measurements of the structure and circulation of the stratosphere and mesosphere, 1970

    NASA Technical Reports Server (NTRS)

    Smith, W. S.; Theon, J. S.; Wright, D. U., Jr.; Casey, J. F.; Horvath, J. J.

    1972-01-01

    Complete data from a total of 26 meteorological rocket soundings of the stratosphere and mesosphere conducted from Barrow, Alaska; Churchill, Canada; and Wallops Island, Va., are presented. These data consist of temperature, pressure, density, and wind profiles from 16 acoustic grenade soundings that cover the 30- to 90-km altitude range, and temperature, pressure, and density profiles from 10 pitot probe soundings that cover the 25- to 120-km altitude range. Errors for each of the 16 grenade soundings are also included. No analysis of the meteorological significance of the data is attempted.

  5. Observations of the 5-day wave in the mesosphere and lower thermosphere

    NASA Technical Reports Server (NTRS)

    Wu, D. L.; Hays, P. B.; Skinner, W. R.

    1994-01-01

    The 5-day planetary wave has been detected in the winds measured by the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS) in the mesosphere and lower thermosphere (50-110 km). The appearances of the 5-day wave are transient, with a lifetime of 10-20 days in the two-year data set. The structures of selected 5-day wave events are in generally good agreement with the (1,1) Rossby normal mode for both zonal and meridional components. A climatology of the 5-day wave is presented for an altitude of 95 km and latitudes mainly between 40 deg S and 40 deg N.

  6. Latitudinal Dependence of the Energy Input into the Mesosphere by High Energy Electrons

    NASA Technical Reports Server (NTRS)

    Wagner, C. U.; Nikutowski, B.; Ranta, H.

    1984-01-01

    Night-time ionspheric absorption measurements give the possibility to study the precipitation of high energy electrons into the mesosphere during and after magnetospheric storms. The uniform Finnish riometer network was used together with measurements from Kuhlungsborn and Collm (GDR) to investigate the night-time absorption as a function of latitude (L=6.5 to 2.5) and storm-time for seven storms. The common trends visible in all these events are summarized in a schematic average picture, showing the distribution of increased ionospheric absorption as a function of latitude (L value) and storm-time.

  7. Observations of Mesospheric Turbulence by Rocket Probe and VHF Radar, Part 2.4A

    NASA Technical Reports Server (NTRS)

    Royrvik, O.; Smith, L. G.

    1984-01-01

    Data from the Jicamarca VHF radar and from a Languir probe fine-structure on a Nike Orion rocket launched from Punto Lobos, Peru, have been compared. A single mesospheric scattering layer was observed by the radar. The Langmuir probe detected irregularities in the electron-density profile in a narrow region between 85.2 and 86.6 km. It appears from a comparison between these two data sets that turbulence in the neutral atmosphere is the mechanism generating the refractive index irregularities.

  8. The mean observed meteorological structure and circulation of the stratosphere and mesosphere

    NASA Technical Reports Server (NTRS)

    Theon, J. S.; Smith, W. S.; Casey, J. F.; Kirkwood, B. R.

    1972-01-01

    Meteorological soundings of the upper stratosphere and mesosphere, conducted with in situ rocket techniques during all seasons of the year from several sites, ranging in latitude from 8 deg S to 71 deg N, are analyzed. The resulting data are compiled into mean monthly and seasonal profiles of temperature, pressure, density, and wind for each site and are presented in graphical and tabular form. Analyses of these mean values produced time cross sections, quasi-meridional cross sections, and constant level maps which are included.

  9. Influence of sprite streamers in the mesospheric chemical and thermal balance

    NASA Astrophysics Data System (ADS)

    Parra-Rojas, Francisco C.; Luque, Alejandro; Gordillo-Vázquez, Francisco J.

    2015-04-01

    We present new results to contribute to the fundamental understanding of the chemistry of non-equilibrium plasmas produced by nighttime sprite streamers in the mesosphere and their influence on the chemical composition and thermal evolution of the upper atmosphere. This contribution describes the kinetic model used and the time evolution of the concentration of many important species for the sprite and its afterglow through an upgrade of previous TLE kinetic models [1], [2]. A one-dimensional self-consistent model has been developed to study the chemical and thermal effects of a single sprite streamer in the Earth mesosphere. We have used sprite streamer profiles with three different driving current durations (5 ms, 50 ms and 100 ms) between 50 and 80 km of altitude and considering a kinetic scheme of air with 20 chemical species. Our model predicts strong increases in practically all the concentrations of the species studied at the moment of the streamer head passage. Moreover, their densities remain high during the streamer afterglow phase. The electron concentration can reach values of up to 108 cm-3 in the three cases analyzed. The model also predicts an important enhancement, of several orders of magnitude above ambient values, of nitrogen oxides (NOx and N2O) and the considered metastables species (N2(A), O2(a), O2(b)). Metastables are capable of storing energy for relatively long time (hundreds of seconds). On the other hand, we found that the 4.26 μm IR emission brightness of CO2 can exceed in 4 orders of magnitude the threshold of visibility (1 MR) at low altitudes (< 65 km) for the cases of intermediate (50 ms) and long (100 ms) driving currents. These results suggest the possibility of detecting sprite IR emissions from space with the appropriate instrumentation. Moreover, according to our model, the Meinel emission brightness of N2+ could also reach the threshold of visibility below 50 km. Finally, we found that the thermal impact of sprites in the

  10. Measurements of the structure and circulation of the stratosphere and mesosphere, 1971-2

    NASA Technical Reports Server (NTRS)

    Smith, W. S.; Theon, J. S.; Wright, D. U., Jr.; Ramsdale, D. J.; Horvath, J. J.

    1974-01-01

    Complete data from a total of 43 meteorological rocket soundings of the stratosphere and mesosphere conducted from Barrow, Alaska; Churchill, Canada; Wallops Island Va.; and Kourou, French Guiana are presented. These data consist of temperature, pressure, density, and wind profiles from 35 acoustic grenade soundings that cover the 30 to 90 km altitude range, and temperature, pressure, and density profiles from 8 pitot probe soundings that cover the 25 to 120 km altitude range. Errors for each of the 35 acoustic grenade soundings are also included.

  11. Mesospheric hydroxyl airglow signatures of acoustic and gravity waves generated by transient tropospheric forcing

    NASA Astrophysics Data System (ADS)

    Snively, J. B.

    2013-09-01

    Numerical model results demonstrate that acoustic waves generated by tropospheric sources may produce cylindrical "concentric ring" signatures in the mesospheric hydroxyl airglow layer. They may arrive as precursors to upward propagating gravity waves, generated simultaneously by the same sources, and produce strong temperature perturbations in the thermosphere above. Transient and short-lived, the acoustic wave airglow intensity and temperature signatures are predicted to be detectable by ground-based airglow imaging systems and may provide new insight into the forcing of the upper atmosphere from below.

  12. Solar Mesosphere Explorer ultraviolet Spectrometer Measurements of ozone in the 1.0-0.1 mbar region

    NASA Technical Reports Server (NTRS)

    Rusch, D. W.; Barth, C. A.; Thomas, R. J.; Callan, M. T.; Mount, G. H.

    1984-01-01

    The ozone density of the earth's mesosphere in the 1.0-0.1 mbar (48 to 70 km) region has been measured at sunlit latitudes for the period from December 1981 until the present by an ultraviolet spectrometer on the Solar Mesosphere Explorer satellite. Results for 1982 are reported. The ozone mixing ratios are found to be highly variable in time and place, with maxima occurring in the winter hemispheres. The results show complex time variations at all pressure levels, with annual and semiannual variations apparent at most pressures and latitudes. A relative maximum occurs in July at the equator.

  13. Polar Glaciology

    NASA Technical Reports Server (NTRS)

    Robin, G. D.

    1984-01-01

    Two fields of research on polar ice sheets are likely to be of dominant interest during the 1990s. These are: the role of polar ice sheets in the hydrological cycle ocean-atmosphere-ice sheets-oceans, especially in relation to climate change; and the study and interpretation of material in deep ice cores to provide improved knowledge of past climates and of the varying levels of atmospheric constituents such as CO2, NOx, SO2, aerosols, etc., over the past 200,000 years. Both topics require a better knowledge of ice dynamics. Many of the studies that should be undertaken in polar regions by Earth Observing System require similar instruments and techniques to those used elsewhere over oceans and inland surfaces. However to study polar regions two special requirements need to be met: Earth Observing System satellite(s) need to be in a sufficiently high inclination orbit to cover most of the polar regions. Instruments must also be adapted, often by relatively limited changes, to give satisfactory data over polar ice. The observational requirements for polar ice sheets in the 1990s are summarized.

  14. Inter-Hemispheric Coupling During Recent North Polar Summer Periods as Predicted by MaCWAVE/MIDAS Rocket Data and Traced by TIMED/SABER Measurements

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Feofilov, Artem G.; Kutepov, Alexander A.; Pesnell, W. Dean; Schmidlin, Francis J.

    2011-01-01

    In July, 2002, the MaCWAVE-MIDAS Rocket Program was launched from And0ya Rocket Range (ARR) in Norway. Data from these flights demonstrated that the polar summer mesosphere during this period was unusual, at least above ARR. Theoretical studies have since been published that imply that the abnormal characteristics of this polar summer were generated by dynamical processes occurring in the southern polar winter hemisphere. We have used data from the SABER instrument aboard the NASA TIMED Satellite to study these characteristics and compare them with the features observed in the ensuing eight years. For background, the TIMED Satellite was launched on December 7, 2001 to study the dynamics and energy of the mesosphere and lower thermosphere. The SABER instrument is a limb scanning infrared radiometer designed to measure temperature of the region as well as a large number of minor constituents. In this study, we review the MaCWAVE rocket results. Next, we investigate the temperature characteristics of the polar mesosphere as a function of spatial and temporal considerations. We have used the most recent SABER dataset (1.07). Weekly averages are used to make comparisons between the winter and summer hemispheres. Furthermore, the data analysis agrees with recent theoretical studies showing that this behavior is a result of anomalous dynamical events in the southern hemisphere. The findings discussed here clearly show the value of scientific rocket flights used in a discovery mode.

  15. International Polar Year Observations From the International Space Station

    NASA Technical Reports Server (NTRS)

    Pettit, Donald R.; Runco, Susan; Byrne, Gregory; Willis, Kim; Heydorn, James; Stefanov, William L.; Wilkinson, M. Justin; Trenchard, Michael

    2006-01-01

    Astronauts aboard the International Space Station (ISS) have several opportunities each day to observe and document high-latitude phenomena. Although lighting conditions, ground track and other viewing parameters change with orbital precessions and season, the 51.6 degree orbital inclination and 400 km altitude of the ISS provide the crew an excellent vantage point for collecting image-based data for IPY investigators. To date, the database of imagery acquired by the Crew Earth Observations (CEO) experiment aboard the ISS (http://eol.jsc.nasa.gov) contains more than 12,000 images of high latitude (above 50 degrees) events such as aurora, mesospheric clouds, sea-ice, high-latitude plankton blooms, volcanic eruptions, and snow cover. The ISS Program will formally participate in IPY through an activity coordinated through CEO entitled Synchronized Observations of Polar Mesospheric Clouds, Aurora and Other Large-scale Polar Phenomena from the ISS and Ground Sites. The activity will augment the existing collection of Earth images taken from the ISS by focusing astronaut observations on polar phenomena. NASA s CEO experiment will solicit requests by IPY investigators for ISS observations that are coordinated with or complement ground-based polar studies. The CEO imagery website (http://eol.jsc.nasa.gov) will provide an on-line form for IPY investigators to interact with CEO scientists and define their imagery requests. This information will be integrated into daily communications with the ISS crews about their Earth Observations targets. All data collected will be cataloged and posted on the website for downloading and assimilation into IPY projects.

  16. Polarizing cues.

    PubMed

    Nicholson, Stephen P

    2012-01-01

    People categorize themselves and others, creating ingroup and outgroup distinctions. In American politics, parties constitute the in- and outgroups, and party leaders hold sway in articulating party positions. A party leader's endorsement of a policy can be persuasive, inducing co-partisans to take the same position. In contrast, a party leader's endorsement may polarize opinion, inducing out-party identifiers to take a contrary position. Using survey experiments from the 2008 presidential election, I examine whether in- and out-party candidate cues—John McCain and Barack Obama—affected partisan opinion. The results indicate that in-party leader cues do not persuade but that out-party leader cues polarize. This finding holds in an experiment featuring President Bush in which his endorsement did not persuade Republicans but it polarized Democrats. Lastly, I compare the effect of party leader cues to party label cues. The results suggest that politicians, not parties, function as polarizing cues. PMID:22400143

  17. Polar motion

    NASA Technical Reports Server (NTRS)

    Kolenkiewicz, R.

    1973-01-01

    Tracking of the Beacon Explorer-C satellite by a precision laser system was used to measure the polar motion and solid earth tide. The tidal perturbation of satellite latitude is plotted as variation in maximum latitude in seconds of arc on earth's surface as a function of the date, and polar motion is shown by plotting the variation in latitude of the laser in seconds of arc along the earth's surface as a function of date

  18. Influences of source conditions on mountain wave penetration into the stratosphere and mesosphere

    NASA Astrophysics Data System (ADS)

    Kaifler, Bernd; Kaifler, Natalie; Ehard, Benedikt; Dörnbrack, Andreas; Rapp, Markus; Fritts, David C.

    2015-11-01

    We present atmospheric gravity wave (GW) measurements obtained by a Rayleigh/Raman lidar at Lauder, New Zealand, (45°S, 170°E) during and after the Deep Propagating Gravity Wave Experiment campaign. GW activity and characteristics are derived from 557 h of high-resolution lidar data recorded between June and November 2014 in an altitude range between 28 and 76 km. In this period, strong GW activity occurred in sporadic intervals lasting a few days. Enhanced stratospheric GW potential energy density is detected during periods with high tropospheric wind speeds perpendicular to New Zealand's Southern Alps. These enhancements are associated with the occurrence of quasi-stationary GW (mountain waves). Surprisingly, the largest response in the mesosphere is observed for conditions with low to moderate lower tropospheric wind speeds (2-12 m/s). On the other hand, large-amplitude mountain waves excited by strong tropospheric forcings often do not reach mesospheric altitudes, either due to wave breaking and dissipation in the stratosphere or refraction away from New Zealand.

  19. A rocket-borne mass analyzer for charged aerosol particles in the mesosphere

    SciTech Connect

    Knappmiller, Scott; Robertson, Scott; Sternovsky, Zoltan; Friedrich, Martin

    2008-10-15

    An electrostatic mass spectrometer for nanometer-sized charged aerosol particles in the mesosphere has been developed and tested. The analyzer is mounted on the forward end of a rocket and has a slit opening for admitting a continuous sample of air that is exhausted through ports at the sides. Within the instrument housing are two sets of four collection plates that are biased with positive and negative voltages for the collection of negative and positive aerosol particles, respectively. Each collection plate spans about an order of magnitude in mass which corresponds to a factor of 2 in radius. The number density of the charge is calculated from the current collected by the plates. The mean free path for molecular collisions in the mesosphere is comparable to the size of the instrument opening; thus, the analyzer performance is modeled by a Monte Carlo computer code that finds the aerosol particles trajectories within the instrument including both the electrostatic force and the forces from collisions of the aerosol particles with air molecules. Mass sensitivity curves obtained using the computer models are near to those obtained in the laboratory using an ion source. The first two flights of the instrument returned data showing the charge number densities of both positive and negative aerosol particles in four mass ranges.

  20. The dynamics of the mesosphere and lower thermosphere: a brief review

    NASA Astrophysics Data System (ADS)

    Vincent, Robert A.

    2015-12-01

    The dynamics of the mesosphere-lower thermosphere (MLT) (60 to 110 km) is dominated by waves and their effects. The basic structure of the MLT is determined by momentum deposition by small-scale gravity waves, which drives a summer-to-winter pole circulation at the mesopause. Atmospheric tides are also an important component of the dynamics of the MLT. Observations from extended ground-based networks, satellites as well as numerical modelling show that non-migrating tidal modes in the MLT are more important than previously thought, with evidence for directly coupling into the thermosphere/ionosphere. Major disturbances lower in the atmosphere, such as wintertime sudden stratospheric warmings, temporarily disrupt the circulation pattern and thermal structure of the MLT. In the equatorial mesosphere, gravity wave driving leads to oscillations in the zonal wind on semiannual time scales, although variability on quasi-biennial time scales is also apparent. Planetary-scale waves such as the quasi-two-day wave temporarily dominate the dynamics of the summertime MLT, especially in the southern hemisphere. Impacts may include short-term changes to the thermal structure and physics of the high-latitude MLT. Here, we briefly review the dynamics of the MLT, with a particular emphasis on developments in the past decade.

  1. First observation of mesospheric wind shear as high as 330 m s-1 km-1

    NASA Astrophysics Data System (ADS)

    Wu, Yong-Fu; Widdel, H.-U.; Offermann, D.

    1995-09-01

    Mesospheric wind profiles with an altitude resolution of 25 m have been obtained by means of radar tracking of foil chaff clouds. Such experiments were performed during winter 1990 at Biscarrosse, France (44°N, 1°W). On one flight, a wind shear as high as 330 m s-1 km-1 at 87.4 km and a region of dynamical instability between 86 and 88 km was measured. This wind shear is believed to be the largest value ever measured in the mesosphere. The region of dynamical instability results from a superposition of two wave motions, and is found to link well with enhanced turbulence and small-scale wave activity. Acknowledgements. I thank D. R. McDiarmid of the Herzberg Institute of Astrophysics, National Research Council, Canada, for important ideas and discussions during the development of this work. I thank the referees for useful comments which have improved the paper. I also thank E.M. Poulter of NIWA for helpful suggestions, and for reading the manuscript and making useful comments. The work was supported by contract CO1309 of the New Zealand Foundation for Research, Science and Technology. Topical Editor C.-G. Fälthammar thanks K. Mursula and W. J. Hughes for their help in evaluating this paper.--> Correspondence to: W. Allan-->

  2. Longterm Variability of the Mesosphere derived from Phase Height Measurements at Kuehlungsborn - Northern Germany

    NASA Astrophysics Data System (ADS)

    Peters, Dieter H. W.; Entzian, G.; Schneidereit, Andrea

    Long-term measurements of physical quantities in the mesosphere are rare. We use long radio wave signals to detect the altitude variation of a level of constant electron density between the transmitter station (162 kHz, Allouis, Haute Provence, France) and our receiver (Northern Germany). The indirect LF-phase height measurement at Kühlungsborn for an altitude of about 82 km was started in February 1959 and run over 50 years without any large breaks. We created a new homogenized data set of daily detrended phase heights from 1959-2009 taking into account a frequency change from 164 to 162 kHz in February 1986. The spectrum shows beside a strong annual and decadal cycle, three peak-periods: i) for about 5 years, ii) for about 3.4 years, and, iii) for about 30 months. To examine the dynamical link between atmospheric layers of the northern hemisphere we used combined Re-Analysis data of ECMWF (ERA-40 and ERA-Interim) for 50 years with an overlap of about 20 years to calculate v’T’ as indicator for planetary wave activity. In addition, for the quasi-biennial oscillation (QBO) like period we found a significant link with the QBO of the subtropical stratosphere, which implies a dynamical relationship to the extra-tropical mesosphere. Further the possible mechanisms of these dynamical relationships are presented and discussed.

  3. Mesospheric Non-Migrating Tides Generated With Planetary Waves: II Influence of Gravity Waves

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G.; Talaat, E. L.; Porter, H. S.; Chan, K. L.

    2003-01-01

    We demonstrated that, in our model, non-linear interactions between planetary waves (PW) and migrating tides could generate in the upper mesosphere non-migrating tides with amplitudes comparable to those observed. The Numerical Spectral Model (NSM) we employ incorporates Hines Doppler Spread Parameterization for small-scale gravity waves (GW), which affect in numerous ways the dynamics of the mesosphere. The latitudinal (seasonal) reversals in the temperature and zonal circulation, which are largely caused by GWs (Lindzen, 198l), filter the PWs and contribute to the instabilities that generate the PWs. The PWs in turn are amplified by the momentum deposition of upward propagating GWs, as are the migrating tides. The GWs thus affect significantly the migrating tides and PWs, the building blocks of non-migrating tides. In the present paper, we demonstrate that GW filtering also contributes to the non-linear coupling between PWs and tides. Two computer experiments are presented to make this point. In one, we simply turn off the GW source to show the effect. In the second case, we demonstrate the effect by selectively suppressing the momentum source for the m = 0 non-migrating tides.

  4. A method for estimating the height of a mesospheric density level using meteor radar

    NASA Astrophysics Data System (ADS)

    Younger, J. P.; Reid, I. M.; Vincent, R. A.; Murphy, D. J.

    2015-07-01

    A new technique for determining the height of a constant density surface at altitudes of 78-85 km is presented. The first results are derived from a decade of observations by a meteor radar located at Davis Station in Antarctica and are compared with observations from the Microwave Limb Sounder instrument aboard the Aura satellite. The density of the neutral atmosphere in the mesosphere/lower thermosphere region around 70-110 km is an essential parameter for interpreting airglow-derived atmospheric temperatures, planning atmospheric entry maneuvers of returning spacecraft, and understanding the response of climate to different stimuli. This region is not well characterized, however, due to inaccessibility combined with a lack of consistent strong atmospheric radar scattering mechanisms. Recent advances in the analysis of detection records from high-performance meteor radars provide new opportunities to obtain atmospheric density estimates at high time resolutions in the MLT region using the durations and heights of faint radar echoes from meteor trails. Previous studies have indicated that the expected increase in underdense meteor radar echo decay times with decreasing altitude is reversed in the lower part of the meteor ablation region due to the neutralization of meteor plasma. The height at which the gradient of meteor echo decay times reverses is found to occur at a fixed atmospheric density. Thus, the gradient reversal height of meteor radar diffusion coefficient profiles can be used to infer the height of a constant density level, enabling the observation of mesospheric density variations using meteor radar.

  5. The double seismic zone in downgoing slabs and the viscosity of the mesosphere

    NASA Technical Reports Server (NTRS)

    Sleep, N. H.

    1979-01-01

    The seismic zone beneath several island arcs between about 100 and 200 km depth consists of an upper zone having down-dip compression and a lower zone having down-dip tension. Several numerical models of the Aleutian arc were computed to test the hypothesis that these double seismic zones are due to sagging of the slab under its own weight. This sagging occurs because the asthenosphere (between about 100 and 200 km) provides little support or resistance to the slab, which is supported from below by the more viscous mesosphere and from above by the lithosphere. The viscosity of the mesosphere was constrained to the interval between 0.25 x 10 to the 22nd and 0.5 x 10 to the 22nd P by noting that the slab would have mainly down-dip compression at higher viscosities and mainly down-dip tension at lower viscosities. The deviatoric stress in the slab and the fault plane between the slab and the island arc is about 200-300 bars (expressed as shear stress). The models were calibrated to the observed depth and gravity anomalies in the trench.

  6. Atomic Oxygen and Energy Balance in the Mesosphere and Lower Thermosphere

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.; Hunt, L. A.; Marshall, T.; Mertens, C. J.; Russell, J. M.; Mast, J. C.; Thompson, R. E.

    2012-12-01

    We use atomic oxygen concentrations measured by SABER in conjunction with measurements of infrared radiative cooling and solar heating to assess the energy balance in the Earth's mesosphere and lower thermosphere. Atomic oxygen plays a central role, particularly in the mesopause region, through heating due to exothermic chemical reactions. The SABER data reveal approximate balance in global heating and cooling on annual timescales. In the 11-year SABER record there is also clear evidence of the solar cycle variation in all of the heat budget terms including atomic oxygen. Long-term changes in heating and cooling rates appear consistent with each other. Uncertainty in the energy budget is due largely to uncertainty in recombination rate coefficients governing exothermic chemical reactions at mesospheric temperatures. In this talk we will show the multitude of energy budget terms derived from SABER observations, the global energy budget, the variability due to the solar cycle, and the uncertainty in the energy balance. We also examine the constraints on the global atomic oxygen concentration based on energy balance considerations.

  7. Global structure and seasonal variability of the migrating terdiurnal tide in the mesosphere and lower thermosphere

    NASA Astrophysics Data System (ADS)

    Yue, Jia; Xu, Jiyao; Chang, Loren C.; Wu, Qian; Liu, Han-Li; Lu, Xian; Russell, James

    2013-12-01

    The morphology of the migrating terdiurnal tide with zonal wavenumber 3 (TW3) in the mesosphere and lower thermosphere (MLT) is revealed using the TIMED satellite datasets from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) and the TIMED Doppler Interferometer (TIDI) instruments from 2002 to 2009, as well as the Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model (TIME-GCM). The annual mean structures of the TW3 from the TIME-GCM clearly resemble the first real symmetric (3,3) Hough mode. The TW3 temperature and zonal wind components have three peaks at midlatitudes and near the equator, while the TW3 meridional wind components show four peaks at mid and low latitudes. These features are consistent with those resolved in SABER temperature and TIDI zonal wind above ~95 km. TW3 components in the TIME-GCM are stronger during winter and spring months at midlatitudes, which is in agreement with previous ground-based radar measurements. On the other hand, TW3 components of temperature, zonal and meridional winds from SABER and TIDI display different seasonal variations at different altitudes and latitudes. The results presented in this paper will provide an observational basis for further modeling study of terdiurnal tide impacts on the thermosphere and ionosphere.

  8. Global distributions of Cly in mesosphere and lower thermosphere observed by SMILES

    NASA Astrophysics Data System (ADS)

    Kuribayashi, Kouta; Kasai, Yasuko

    Chemical and dynamical behavior of anthropogenic chlorine compounds (Cly) have been well understood in stratosphere, while the knowledge above stratosphere, between mesosphere and the top of atmosphere (TOA), is quite poor. The main reason of a lack of understanding is due to a lack of the observation evidence of Cly so far. Cly can be described as Cly = HCl + ClO + HOCl + Cl in mesosphere and lower thermosphere (MLT) region. Recently, the first global distributions of HCl, ClO, and HOCl were performed in MLT region by using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) from the Exposed Module (EM) of the Japanese Experiment Module (JEM) on the International Space Station (ISS) between 12 October 2009 and 21 April 2010. The SMILES instrument employed 4 K submillimeter-wave superconductive heterodyne receivers, and obtained spectra with unprecedented low noise, which is one order of magnitude better performance than previous microwave/sub-millimeter limb instruments in space. We will present the behavior, the global distributions and their chemistry and dynamics, of HCl, ClO, HOCl related with HO2 and O3 in MLT region from SMILES observations and model results.

  9. Annual and semiannual harmonics of wind in the Northern stratosphere, mesosphere, and lower thermosphere

    NASA Astrophysics Data System (ADS)

    Guryanov, Vladimir V.; Jacobi, Christoph; Eliseev, Alexey V.; Fahrutdinova, Antonina N.

    2015-11-01

    Based on the UK MetOffice gridded analysis in the altitudes from the tropopause to the mesopause of the Northern Hemisphere and the meteor radar observations in the mesosphere/lower thermosphere over Kazan (56 °N 49 °E) and Collm (51 °N 13 °E), the annual and semiannual harmonics of the horizontal wind components in the stratosphere, mesosphere, and lower thermosphere are studied for the period 2004-2013. The maxima of the amplitude of the annual harmonics of zonal wind are much more pronounced than the respective maxima for meridional wind. In contrast, the magnitudes of the maxima of the semiannual harmonics are comparable between zonal and meridional wind. The annual harmonics of horizontal wind in the studied layer typically reaches maximum in January-February. The semiannual harmonics of the components of horizontal wind in the stratosphere-lower thermosphere layer basically attains it first maximum in spring or in early summer. The results, included in the present paper, may be used for climate models validation.

  10. Longitudinal structure of the northern higher latitude middle stratosphere to lower mesosphere

    NASA Astrophysics Data System (ADS)

    Lastovicka, Jan; Krizan, Peter; Kozubek, Michal

    2016-07-01

    The meridional wind is relatively little studied but important quantity in the stratosphere and mesosphere. We found a two-core longitudinal structure in meridional wind at northern higher middle latitudes based on MERRA data. The two-core structure covers the middle stratosphere (lower boundary ~50 hPa), upper stratosphere and lower mesosphere (up to at least 0.1 hPa, probably somewhat higher). It is circulation response to the appearance of the blocking Aleutian pressure high, which affects more or less also the zonal wind, temperature and ozone fields. The well-pronounced two core structure occurs only in the winter half of the year (October-March) and only at the Northern Hemisphere. The two-core longitudinal structure in meridional wind is persistent feature. Only a few winters (Januaries) reveal more complex structure; all these winters were observed during the positive phase of the Pacific PNA index. The two core structure and Aleutian pressure high display a westward shift with increasing altitude, which allows the interpretation of the blocking Aleutian pressure high as a stationary planetary wave with the two core structure of meridional wind as a response of the overall circulation to the appearance of this stationary planetary wave in pressure field. Its existence could influence the Brewer-Dobson circulation and also the zonal mean approach to investigations of the middle atmosphere.

  11. Mesospheric sodium structure variability on horizontal scales relevant to laser guide star asterisms

    NASA Astrophysics Data System (ADS)

    Pfrommer, Thomas; Hickson, Paul

    2012-07-01

    Adaptive optics (AO) systems of modern telescopes use laser guide stars, produced by resonant excitation of sodium atoms in the mesosphere at around 92 km. Wavefront sensor subapertures, if sufficiently far away from the primary mirror center, resolve the internal structure of the sodium layer. The variability of this structure is caused by the influence of gravity waves and wind shear turbulence. The relevance of such dynamics to AO has been investigated over the past four years. A high-resolution lidar system, employed at the 6-m liquid mirror telescope, which is located near Vancouver, Canada, has been used to study mesospheric dynamics, such as the temporal behavior of the mean altitude. The main results from this study have been published elsewhere and will be summarized here. Along with the temporal variability, the mean altitude on horizontal scales of order IOs of meters has been studied by introducing a tip/tilt stage in the experimental setup. This enables us to swap the laser pulse within a 1 arcmin field of view. The horizontal mean altitude structure function has been measured on 10 observing nights between July and August 2011. Results reveal severe structural differences and a strong horizontal anisotropy. Individual laser beacons in a laser guide star asterism will therefore have at the same time significantly different focus heights. By propagating this 2d structure function to the entrance pupil of a 39 m telescope, we derive a differential focus wavefront error map.

  12. Chemical and thermal impacts of sprite streamers in the Earth's mesosphere

    NASA Astrophysics Data System (ADS)

    Parra-Rojas, F. C.; Luque, A.; Gordillo-Vázquez, F. J.

    2015-10-01

    A one-dimensional self-consistent model has been developed to study the chemical and thermal effects of a single sprite streamer in the Earth's mesosphere. We have used sprite streamer profiles with three different driving current durations (5 ms, 50 ms, and 100 ms) between 50 and 80 km of altitude and considering a kinetic scheme of air with more than 90 chemical species. Our model predicts strong increases in practically all the concentrations of the species studied at the moment of the streamer head passage. Moreover, their densities remain high during the streamer afterglow phase. The concentration of electrons can reach values of up to 108 cm-3 in the three cases analyzed. The model also predicts an important enhancement, of several orders of magnitude above ambient values, of nitrogen oxides and several metastables species. On the other hand, we found that the 4.26 μm IR emission brightness of CO2 can reach 10 GR at low altitudes (< 65 km) for the cases of intermediate (50 ms) and long (100 ms) driving currents. These results suggest the possibility of detecting sprite IR emissions from space with the appropriate instrumentation. Finally, we found that the thermal impact of sprites in the Earth's mesosphere is proportional to the driving current duration. This produces variations of more than 40 K (in the extreme case of a 100 ms driving current) at low altitudes (< 55 km) and at about 10 s after the streamer head.

  13. Simultaneous Imaging and Lidar Measurements of a Breaking Internal Gravity Wave in the Mesosphere

    NASA Astrophysics Data System (ADS)

    Smith, S. M.; Friedman, J.; Raizada, S.; Tepley, C.; Baumgardner, J.; Mendillo, M.

    2004-05-01

    A large wave event was observed in the three upper-mesospheric (80 to 105 km) airglow emissions of O(1S), Na and OH by the Boston University all-sky imager at the Arecibo Observatory during the night of 2/3 May 2003. Simultaneous measurements of the 80 to 105 km height region were made by two co-located potassium and sodium resonance lidars. The K lidar measurements indicated the presence of a large temperature inversion (possibly the largest recorded in the mesopause region to date) of 90 K peak-to-peak between 88 and 96 km during the zenith transit time of the disturbance. Strong vertical motions were observed to occur in the K and Na layers during the passage of the disturbance - the top and bottom sides of both layers increased in height by 3 to 5 km. The instability exhibited several characteristics of a bore - a non-linear disturbance commonly observed in rivers, oceans, and the lower atmosphere, and recently identified in the mesosphere. However, the vertical phase variation suggested that it was a large downwardly-propagating internal gravity wave that was in the process of breaking, causing overturning and turbulence, probably as a result of interaction with a large coincident temperature maximum. The behavior of the disturbance was very similar to that of a so-called ''wall''-type event (Swenson and Espy, 1995) and the event suggests that ''wall''-type events and bores are different manifestations of a single type of disturbance.

  14. Characterization of exceptionally strong mesospheric wave events using all-sky and zenith airglow observations

    NASA Astrophysics Data System (ADS)

    Smith, Steven M.; Scheer, Jürgen; Reisin, Esteban R.; Baumgardner, Jeffrey; Mendillo, Michael

    2006-09-01

    Two unusually clear mesospheric gravity wave events were observed by the Boston University all-sky imager and the Argentine airglow spectrometer on two consecutive nights at the El Leoncito Observatory, Argentina (31.8°S, 69.3°W), during August 2001. Both events exhibited brightness amplitudes an order of magnitude above typical values. The first event had the appearance of a large-amplitude (>60% in OH(6-2), 22% in O2, and 37% in O(1S) emissions (peak to peak), compared to 1-5% typically), upward propagating gravity wave with pronounced nonlinear behavior. The waves also showed noticeably curved wavefronts, indicating that they had originated from a relatively small source region within ˜180 km of El Leoncito. Estimates of the vertical flux of horizontal energy and momentum for the wave event in the OH and O2 emissions were very large compared to typical values, and they also indicated a high degree of flux divergence over the nominal 8 km altitude between the two layers. The second event occurred on the following night and exhibited a frontal morphology and behavior consistent with an internal ducted gravity wave showing nonlinear behavior akin to a mesospheric bore. The disturbance also had several interesting characteristics; in particular, the propagation speed decreased during its passage across the sky. In addition, a strong vertical temperature gradient due to the semidiurnal tide appeared to influence the occurrence of the bore event.

  15. A preliminary zonal mean climatology of water vapour in the stratosphere and mesosphere

    NASA Astrophysics Data System (ADS)

    Pumphrey, Hugh C.; Rind, D.; Russell, J. M.; Harries, J. E.

    The Microwave Limb Sounder on the UARS satellite measures water vapour concentration in the stratosphere and mesosphere. Water vapour profiles are retrieved from radiance measurements using a version of the optimal estimation algorithm. This requires an a priori profile which is obtained from a climatology. The MLS retrieval currently uses the standard UARS pre-launch climatology, which contains water vapour based on a 2-D model constrained to LIMS data in the stratosphere. This climatology has several defects which affect the ability of MLS to retrieve water vapour. This paper presents a new climatology constructed from the HALOE (HALogen Occultation Experiment) and SAGE II (Stratospheric Aerosol and Gas Experiment) data, which have become available recently. The new climatology is more realistic in several ways, particularly in the mesosphere and near the tropopause. It is proving to be an improvement as an a priori for MLS retrievals and might also have other uses. The paper will present the climatology, show how it was constructed, and compare it to the UARS pre-launch climatology and to various other data. As it stands, this climatology is not suitable for a reference atmosphere, but it is an improvement on CIRA part III in some way simply because it contains more accurate data and shows a number of new features. Suggestions are made for constructing an improved reference climatology for middle atmosphere water vapour.

  16. Seasonal dependence of mesospheric gravity waves ( <100 Km) at Peach Mountain Observatory, Michigan

    NASA Astrophysics Data System (ADS)

    Wu, Q.; Killeen, T. L.

    We present results from a 14-month study of all-sky camera observations of the Hydroxyl (OH) nightglow made at the Peach Mountain Observatory, Michigan (42.3°N 83.7°W) Spatial variations in the observed OH airglow images have been used to assess gravity-wave (GW) occurrence frequency at ∼85 km altitude as a function of season. A Strong seasonal dependence of mesospheric GW activity is observed, with peak activity in the summer months and much reduced activity during the winter months. Gravity waves (as defined by observed coherent variations in relative OH brightnesses of >∼7.5) were found to be present on about 70% of the clear-sky nights during the summer months. During the spring, fall, and winter months, however, the observed GW occurrence frequency was very low (<10%). Most of the GWs were observed to propagate towards the eastward hemisphere. We suggest that the tropospherically-generated GWs are anisotropic (eastward) thus passing through to the mesosphere only in the summer and being filtered out by the intervening neutral winds during other seasons. It is also possible that the GWs are able to reach higher altitudes without breaking because of their smaller amplitudes at lower altitudes during the summer season relative to the winter season.

  17. Mesospheric temperature estimation from meteor decay times during Geminids meteor shower

    NASA Astrophysics Data System (ADS)

    Kozlovsky, Alexander; Lukianova, Renata; Shalimov, Sergey; Lester, Mark

    2016-02-01

    Meteor radar observations at the Sodankylä Geophysical Observatory (67° 22'N, 26° 38'E, Finland) indicate that the mesospheric temperature derived from meteor decay times is systematically underestimated by 20-50 K during the Geminids meteor shower which has peak on 13 December. A very good coincidence of the minimum of routinely calculated temperature and maximum of meteor flux (the number of meteors detected per day) was observed regularly on that day in December 2008-2014. These observations are for a specific height-lifetime distribution of the Geminids meteor trails and indicate a larger percentage of overdense trails compared to that for sporadic meteors. A consequence of this is that the routine estimates of mesospheric temperature during the Geminids are in fact underestimates. The observations do, however, indicate unusual properties (e.g., mass, speed, or chemical composition) of the Geminids meteoroids. Similar properties were found also for Quadrantids in January 2009-2015, which like the Geminids has as a parent body an asteroid, but not for other meteor showers.

  18. Imaging mesospheric winds using the Michelson interferometer for airglow dynamics imaging

    NASA Astrophysics Data System (ADS)

    Langille, Jeffery; Ward, William E.

    2016-07-01

    The first ground based images of mesospheric winds in airglow are presented and discussed in this paper. These were obtained with the Michelson Interferometer for Airglow Dynamics Imaging (MIADI)a ground based field widened Michelsoin interferometer designed to obtain two dimensional images of the line of sight Doppler wind and irradiance field in the mesosphere. The purpose of this instrument is to measure perturbations in line-of-sight wind and airglow irradiance associated with gravity waves. In its current configuration, the instrument observes an ~80 km x ~80 km region of the night sky in ~33 minutes using the O(1S) emission at 557.73 nm and the OH (6, 2) P1 (2) emission at 839.918 nm. The instrument was installed and tested at a field site outside Fredericton, NB (45.96 N, 66.65 W) during the summer of 2014. Successful measurements over a six hour period were obtained on July 31, 2014. Variations in the meridional and zonal wind were observed that are consistent with a semi-diurnal tide with an amplitude of ˜ 35 m/s. Small scale variations (< 10 m/s) were also observed that indicate the presence of gravity waves. In this paper, the instrument concept will be presented and the field measurements and their precision and accuracy discussed.

  19. High-resolution observations of mesospheric layers with the Jicamarca VHF radar

    NASA Astrophysics Data System (ADS)

    Lehmacher, G. A.; Guo, L.; Kudeki, E.; Reyes, P. M.; Akgiray, A.; Chau, J. L.

    We report new results from the 50-MHz Jicamarca radar in Peru (12°S, 77°W), which is able to observe backscatter from the daytime mesosphere on any given day. Since 2005, the radar has been operated in a high-power MST-ISR mode for 3-day runs four times per year to study the seasonal variation of mesospheric echoes. Doppler spectra are obtained with 1 min and 150-m nominal resolution yielding power, horizontal and vertical winds, and spectral width. The rich echo structures contain braids and billows suggestive of Kelvin-Helmholtz instability (KHI). We present three cases; (1) a short sequence of billows growing in height and becoming unstable; (2) a long train of billows showing high levels of turbulence at two different locations; and (3) a series of billows passing only slowly through the field of view. In all cases, the layers were associated with strong wind shears, mature billows were 1-1.5 km tall, and separation of KH phase fronts was 8-10 km. We compare our observations with OH imager observation and numerical simulations.

  20. A Two-Year Study of 50-MHz Mesospheric Echoes and Winds at Jicamarca, Peru

    NASA Astrophysics Data System (ADS)

    Lehmacher, G. A.; Guo, L.; Kudeki, E.; Akgiray, A.; Reyes, P.; Chau, J.

    2007-05-01

    The Jicamarca 50-MHz radar has been operated since December 2004 for over 30 days in a MST-ISR mode receiving coherent scatter between 11 to 180 km with nominal 150 m resolution and incoherent scatter between 200 and 900 km. This paper will focus on the highly structured turbulent layers from the daytime mesosphere (D region) between 55 and 85 km. Non-linear fitting of a generalized Gaussian yields power, Doppler velocities and spectral width for four fixed beams, from which horizontal and vertical winds, momentum fluxes and turbulent velocities are calculated. The ISR data are modeled to determine electron density profiles (which are compared to ionosonde data) and also calibration factors for all beams to derive absolute reflectivities for the mesospheric turbulent scatter. Earlier experiments have shown evidence for annual and semiannual variability in the winds, signatures of the diurnal tide, inertia-gravity waves and instabilities. The more comprehensive data set covering over two years is employed to study the variability of small-scale dynamics and its correlation with the seasonal change of the prevailing winds.

  1. Rocket-borne Ion Mass Spectrometer for the Mesosphere That is Pumped by Rocket Aerodynamics

    NASA Astrophysics Data System (ADS)

    Sternovsky, Zoltan; Smith, Steven; Robertson, Scott

    The mesospheric region close to the mesopause is populated by electrons, ions and aerosol particles. The number density of aerosol particles may exceed that of the background plasma creating conditions where the free electron density is reduced. Understanding the full charge balance of the region requires the simultaneous detection of electrons, charged aerosol particles and ions. Rocket borne instruments for the measurement of electrons and aerosols are readily available. Mass spectrometers for ions have been flown that were evacuated by cryogenic vacuum pumps with liquid helium or neon. There have not been flights since 1993 because these instruments required expensive deliveries of cryogens and frequent refilling. Advances in (1) aerodynamic modeling, (2) mass spectrometer design, and (3) ion detection technology make possible a new approach to mass spectrometry in the mesosphere in which the spectrometer is pumped by the flow around the rocket. A miniature Rotating Field Mass Analyzer (RFMS) is presented that is suitable for the measurement of ions in from 70 km upward. RFMS has a 2 x 2 x 20 mm3 velocity selection cell and utilizes and advanced ion detector that is capable of single ions operation mode at these altitudes. The instrument is pumped by the aerodynamic effect of the supersonic payload. A prototype version of RFMS is under laboratory testing.

  2. On the heterogeneous nucleation of mesospheric ice on meteoric smoke particles: Microphysical modeling

    NASA Astrophysics Data System (ADS)

    Asmus, Heiner; Wilms, Henrike; Strelnikov, Boris; Rapp, Markus

    2014-10-01

    Meteor smoke particles (MSP), which are thought to be the nucleation germs for mesospheric ice, are currently discussed to consist of highly absorbing materials such as magnesiowüstite, hematite or magnesium-iron-silicates and may therefore be warmer than the ambient atmosphere. In order to quantify the temperature difference between MSP and the atmosphere we developed a model to calculate the MSP equilibrium temperature in radiational and collisional balance. The temperature difference between MSP and the surrounding atmosphere strongly depends on the composition of the MSP, especially on the relative iron content, where a higher iron content leads to warmer MSP. We then derive an expression of the nucleation rate of mesospheric ice particles which explicitly accounts for this temperature difference. We find that the nucleation rate is strongly reduced by several orders of magnitude if the germ temperature is increased by only a few Kelvin. Implementing this nucleation rate depending on the germ temperature into CARMA, the Community Aerosol and Radiation Model for Atmospheres, we find that fewer but larger ice particles are formed compared to a reference scenario with no temperature difference between MSP and ambient atmosphere. This may indicate that iron-rich MSP are not ideal ice nuclei and that either other MSP-types or other nucleation pathways (e.g. wave induced heterogeneous nucleation or even homogeneous nucleation) are responsible for ice formation at the mesopause.

  3. In-situ observations of mesospheric aerosol particles and their impact on the D-region charge balance: Highlights from the ECOMA sounding rocket program (2006 - 2010)

    NASA Astrophysics Data System (ADS)

    Rapp, M.; Friedrich, M.; Strelnikov, B.; Hoppe, U.; Plane, J. M.

    2012-12-01

    Over the years 2006 - 2010 a total of 9 sounding rockets was successfully launched in the scope of the Norwegian-German ECOMA (= Existence and Charge state Of Meteoric smoke particles in the middle Atmosphere) project. While the primary target of these observations was the characterization of the properties of meteoric smoke particles (MSP), both MSP and mesospheric ice particles in the vicinity of the cold polar summer mesopause were investigated. This presentation gives an overview of the major results of this project covering subjects such as the charging properties of MSP and ice particles, the impact of this charging process on the D-region charge balance, and the microphysical properties of the MSP. Concerning the latter, emphasis is spent on the most recent results from a campaign in December 2010 during which two sounding rockets were launched with improved particle detectors that were designed to provide constraints on the photoelectric work function of the particles. These experimental results are further discussed on the basis of quantum mechanical calculations of the electronic structure of cluster molecules which are likely candidates for MSP. These calculations allow a tentative interpretation of the observations in terms of MSP size and altitude variations as well as their photoelectric properties.

  4. Quantum vacuum and dark matter

    NASA Astrophysics Data System (ADS)

    Hajdukovic, Dragan Slavkov

    2012-01-01

    Recently, the gravitational polarization of the quantum vacuum was proposed as alternative to the dark matter paradigm. In the present paper we consider four benchmark measurements: the universality of the central surface density of galaxy dark matter haloes, the cored dark matter haloes in dwarf spheroidal galaxies, the non-existence of dark disks in spiral galaxies and distribution of dark matter after collision of clusters of galaxies (the Bullet cluster is a famous example). Only some of these phenomena (but not all of them) can (in principle) be explained by the dark matter and the theories of modified gravity. However, we argue that the framework of the gravitational polarization of the quantum vacuum allows the understanding of the totality of these phenomena.

  5. Temperature minima in the average thermal structure of the middle mesosphere (70 - 80 km) from analysis of 40- to 92-km SME global temperature profiles

    NASA Technical Reports Server (NTRS)

    Clancy, R. Todd; Rusch, David W.; Callan, Michael T.

    1994-01-01

    Global temperatures have been derived for the upper stratosphere and mesosphere from analysis of Solar Mesosphere Explorer (SME) limb radiance profiles. The SME temperature represent fixed local time observations at 1400 - 1500 LT, with partial zonal coverage of 3 - 5 longitudes per day over the 1982-1986 period. These new SME temperatures are compared to the COSPAR International Ionosphere Reference Atmosphere 86 (CIRA 86) climatology (Fleming et al., 1990) as well as stratospheric and mesospheric sounder (SAMS); Barnett and Corney, 1984), National Meteorological Center (NMC); (Gelman et al., 1986), and individual lidar and rocket observations. Significant areas of disagreement between the SME and CIRA 86 mesospheric temperatures are 10 K warmer SME temperatures at altitudes above 80 km. The 1981-1982 SAMS temperatures are in much closer agreement with the SME temperatures between 40 and 75 km. Although much of the SME-CIRA 86 disagreement probably stems from the poor vertical resolution of the observations comprising the CIRA 86 modelm, some portion of the differences may reflect 5- to 10-year temporal variations in mesospheric temperatures. The CIRA 86 climatology is based on 1973-1978 measurements. Relatively large (1 K/yr) 5- to 10-year trends in temperatures as functions of longitude, latitude, and altitude have been observed for both the upper stratosphere (Clancy and Rusch, 1989a) and mesosphere (Clancy and Rusch, 1989b; Hauchecorne et al., 1991). The SME temperatures also exhibit enhanced amplitudes for the semiannual oscillation (SAO) of upper mesospheric temperatures at low latitudes, which are not evident in the CIRA 86 climatology. The so-called mesospheric `temperature inversions' at wintertime midlatitudes, which have been observed by ground-based lidar (Hauschecorne et al., 1987) and rocket in situ measurements (Schmidlin, 1976), are shown to be a climatological aspect of the mesosphere, based on the SME observations.

  6. Mesospheric temperature observations at Resolute (75°N) in the context of solar flux and quasi-biennial variations

    NASA Astrophysics Data System (ADS)

    Shepherd, Gordon G.; Cho, Young-Min; Shepherd, Marianna G.

    2010-08-01

    A spectral airglow temperature imager was operated at Resolute (75°N) in northern Canada from 2001 to 2009, providing mesospheric rotational temperatures from the hydroxyl radical OH Meinel (6,2) band airglow from a nominal altitude of 87 km. The year-to-year temperature variability, which included a full maximum to minimum of the solar cycle, was investigated and compared with the temperatures at 22.5 km obtained from radiosonde measurements at the same site. For both data sets, an anticorrelation with the quasi-biennial oscillation (QBO) was found, in the sense that a positive (eastward) zonal wind at the equator corresponded to negative temperature anomalies for both regions, a relationship that had already been recognized for the lower stratosphere. Plots of the monthly mesospheric temperatures versus solar flux, done separately for the two phases of the QBO, showed a high correlation for the westerly phase of the QBO and a low correlation for the easterly phase, as has been recognized for the lower stratosphere. Finally, when the upper mesospheric monthly temperature anomalies were plotted versus those for the lower stratosphere, a high correlation was found for the westerly phase of the QBO and a low correlation for the easterly phase. This is also a new finding for the upper mesosphere and indicates either a coupling between the two regions or simply a common response to the same source: solar flux, the influence of which is modulated by the QBO.

  7. The CSSL (combined sporadic structures and layers) payload: In situ observations of mesospheric sodium and related parameters

    NASA Technical Reports Server (NTRS)

    Machuga, David W.; Kane, Timothy J.; Wheeler, Timothy F.; Croskey, Charles L.; Mathews, John D.; Mitchell, John D.

    1997-01-01

    The objectives, design and results of the sensor systems for the combined sporadic structures and layers (CSSL) payload are analyzed. The CSSL main objectives were to: validate current models of mesospheric sodium chemistry; explore the relationship between turbulence and Na fluctuations; and to explore the relationship between high latitude electric fields and the formation of Na anomalies.

  8. Neutron Polarizers Based on Polarized 3He

    SciTech Connect

    William M. Snow

    2005-05-01

    The goal of this work, which is a collaborative effort between Indiana University, NIST, and Hamilton College, is to extend the technique of polarized neutron scattering into new domains by the development and application of polarized 3He-based neutron spin filters. After the IPNS experiment which measured Zeeman sp[litting in surface scattered neutrons using a polarized 3He cell as a polarization analyzer transporterd by car from Bloomington to Chicago, the Indiana work focused on technical developments to improve the 3He polarization of the Indiana compression system. The compression system was rebuilt with a new valve system which allows gas trapped in the dead volume of the compressors at the end of the piston stroke to be exhausted and conducted back to the optical pumping cell where it can be repolarized. We also incorporated a new intermediate storage volume made at NIST from 1720 glass which will reduce polarization losses between the compressors. Furthermore, we improved the stability of the 1083 nm laser by cooling the LMA rod. We achieved 60% 3he polarization in the optical pumping cell and 87% preservation of the polarization during compression. In parallel we built a magnetically-shielded transport solenoid for use on neutron scattering instruments such as POSY which achieves a fractional field uniformity of better than 10-3 per cm. The field was mapped using an automated 3D field mapping system for in-situ measurement of magnetic field gradients Diluted magnetic semiconductors offer many exciting opportunities for investigation of spintronic effects in solids and are certain to be one of the most active areas of condensed matter physics over then next several years. These materials can act as efficient spin injectors for devices that make use of spin-dependent transport phenomena. We just (late July 2002) finished a neutron reflectivity experiment at NIST on a GaMnAs trilayer film. This material is a ferromagnetic semiconductor which is of interest

  9. Changes in the concentration of mesospheric O3 and OH during a highly relativistic electron precipitation event

    NASA Astrophysics Data System (ADS)

    Goldberg, R. A.; Jackman, C. H.; Baker, D. N.; Herrero, F. A.

    Highly relativistic electron precipitation events (HREs) can provide a major source of energy affecting ionization levels and minor constituents in the mesosphere. Based on satellite data, these events are most pronounced during the minimum of the solar sunspot cycle, increasing in intensity, spectral hardness and frequency of occurrence as solar activity declines. Furthermore, although the precipitating flux is modulated diurnally in local time, the noontime maximum is very broad, exceeding several hours. Since such events can be sustained up to several days, their integrated effect in the mesosphere can dominate over those of other external sources such as relativistic electron precipitation events (REPs) and auroral precipitation. In this work, the effects of HRE relativistic electrons on the neutral minor constituents OH and O3 are modeled during a modest HRE, to estimate their anticipated impact on mesospheric heating and dynamics. The data to be discussed and analyzed were obtained by rocket at Poker Flat, Alaska on May 13, 1990 during an HRE observed at midday near the peak of the sunspot cycle. Solid state detectors were used to measure the electron fluxes and their energy spectra. An x-ray scintillator was included to measure bremsstrahlung x-rays produced by energetic electrons impacting the upper atmosphere; however, these were found to make a negligible contribution to the energy deposition during this particular HRE event. Hence, the energy deposition produced by the highly relativistic electrons dominated within the mesosphere and was used exclusively to infer changes in the middle atmospheric minor constituent abundances. By employing a two-dimensional photochemical model developed for this region at Goddard Space Fight Center, it has been found that for this event, peak modifications in the neutral minor species occurred near 80 km. A maximum enhancement for OH was calculated to be over 40% at the latitude of the launch site, which in turn induced a

  10. Solar Energy Deposition Rates in the Mesosphere Derived from Airglow Measurements: Implications for the Ozone Model Deficit Problem

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Garcia, Rolando R.; Roble, Raymond G.; Hagan, Maura

    2000-01-01

    We derive rates of energy deposition in the mesosphere due to the absorption of solar ultraviolet radiation by ozone. The rates are derived directly from measurements of the 1.27-microns oxygen dayglow emission, independent of knowledge of the ozone abundance, the ozone absorption cross sections, and the ultraviolet solar irradiance in the ozone Hartley band. Fifty-six months of airglow data taken between 1982 and 1986 by the near-infrared spectrometer on the Solar-Mesosphere Explorer satellite are analyzed. The energy deposition rates exhibit altitude-dependent annual and semi-annual variations. We also find a positive correlation between temperatures and energy deposition rates near 90 km at low latitudes. This correlation is largely due to the semiannual oscillation in temperature and ozone and is consistent with model calculations. There is also a suggestion of possible tidal enhancement of this correlation based on recent theoretical and observational analyses. The airglow-derived rates of energy deposition are then compared with those computed by multidimensional numerical models. The observed and modeled deposition rates typically agree to within 20%. This agreement in energy deposition rates implies the same agreement exists between measured and modeled ozone volume mixing ratios in the mesosphere. Only in the upper mesosphere at midlatitudes during winter do we derive energy deposition rates (and hence ozone mixing ratios) consistently and significantly larger than the model calculations. This result is contrary to previous studies that have shown a large model deficit in the ozone abundance throughout the mesosphere. The climatology of solar energy deposition and heating presented in this paper is available to the community at the Middle Atmosphere Energy Budget Project web site at http://heat-budget.gats-inc.com.

  11. Solar energy deposition rates in the mesosphere derived from airglow measurements: Implications for the ozone model deficit problem

    NASA Astrophysics Data System (ADS)

    Mlynczak, Martin G.; Garcia, Rolando R.; Roble, Raymond G.; Hagan, Maura

    2000-07-01

    We derive rates of energy deposition in the mesosphere due to the absorption of solar ultraviolet radiation by ozone. The rates are derived directly from measurements of the 1.27-μm oxygen dayglow emission, independent of knowledge of the ozone abundance, the ozone absorption cross sections, and the ultraviolet solar irradiance in the ozone Hartley band. Fifty-six months of airglow data taken between 1982 and 1986 by the near-infrared spectrometer on the Solar-Mesosphere Explorer satellite are analyzed. The energy deposition rates exhibit altitude-dependent annual and semi-annual variations. We also find a positive correlation between temperatures and energy deposition rates near 90 km at low latitudes. This correlation is largely due to the semiannual oscillation in temperature and ozone and is consistent with model calculations. There is also a suggestion of possible tidal enhancement of this correlation based on recent theoretical and observational analyses. The airglow-derived rates of energy deposition are then compared with those computed by multidimensional numerical models. The observed and modeled deposition rates typically agree to within 20%. This agreement in energy deposition rates implies the same agreement exists between measured and modeled ozone volume mixing ratios in the mesosphere. Only in the upper mesosphere at midlatitudes during winter do we derive energy deposition rates (and hence ozone mixing ratios) consistently and significantly larger than the model calculations. This result is contrary to previous studies that have shown a large model deficit in the ozone abundance throughout the mesosphere. The climatology of solar energy deposition and heating presented in this paper is available to the community at the Middle Atmosphere Energy Budget Project web site at http://heat.budget.gats.inc.com.

  12. LIMS (Limb Infrared Monitor of the Stratosphere) observation of traveling planetary waves and potential vorticity advection in the stratosphere and mesosphere

    SciTech Connect

    Dunkerton, T.J. )

    1991-02-20

    Eastward and westward traveling waves were observed by the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) during the northern winter 1978-1979. Eastward waves were prevalent in early winter and were involved in a minor Canadian warming in December 1978. A large westward traveling wave, as described by previous authors, was observed in January 1979 during a series of minor warmings. By comparing these two events, it is shown that in both cases the superposition of traveling and quasi-stationary waves led to constructive interference that was responsible for the warmings. However, there was significant asymmetry between eastward and westward traveling components. Eastward disturbances were confined mostly within the polar vortex, whereas quasi-stationary and westward traveling components propagated to the vortex periphery and beyond, into the tropics and mid-latitude mesosphere. This behavior is consistent with Rossby wave propagation and indicates that the location and magnitude of planetary wave breaking is sensitive to the frequency spectrum entering the middle atmosphere. However, this asymmetry is also a signature of the nonlinear critical layer as it projects onto the frequency spectrum. Both interpretations are shown to be valid during wave events observed by LIMS. A local Eulerian analysis of potential vorticity (PV) transport indicates that adiabatic, geostrophic advection by the resolvable scales of motion explains qualitatively (but not quantitatively) the observed potential vorticity tendencies in the LIMS northern hemisphere winter. In particular, calculated advection explains the eastward rotation of the main vortex, intrusion of low PV air into the polar cap, and formation of high PV filaments at the vortex periphery.

  13. Short-term nonmigrating tide variability in the mesosphere, thermosphere, and ionosphere

    NASA Astrophysics Data System (ADS)

    Pedatella, N. M.; Oberheide, J.; Sutton, E. K.; Liu, H.-L.; Anderson, J. L.; Raeder, K.

    2016-04-01

    The intraseasonal variability of the eastward propagating nonmigrating diurnal tide with zonal wave number 3 (DE3) during 2007 in the mesosphere, ionosphere, and thermosphere is investigated using a whole atmosphere model reanalysis and satellite observations. The atmospheric reanalysis is based on implementation of data assimilation in the Whole Atmosphere Community Climate Model (WACCM) using the Data Assimilation Research Testbed (DART) ensemble Kalman filter. The tidal variability in the WACCM+DART reanalysis is compared to the observed variability in the mesosphere and lower thermosphere (MLT) based on the Thermosphere Ionosphere Mesosphere Energetics Dynamics satellite Sounding of the Atmosphere using Broadband Emission Radiometry (TIMED/SABER) observations, in the ionosphere based on Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations, and in the upper thermosphere (˜475 km) based on Gravity Recovery and Climate Experiment (GRACE) neutral density observations. To obtain the short-term DE3 variability in the MLT and upper thermosphere, we apply the method of tidal deconvolution to the TIMED/SABER observations and consider the difference in the ascending and descending longitudinal wave number 4 structure in the GRACE observations. The results reveal that tidal amplitude changes of 5-10 K regularly occur on short timescales (˜10-20 days) in the MLT. Similar variability occurs in the WACCM+DART reanalysis and TIMED/SABER observations, demonstrating that the short-term variability can be captured in whole atmosphere models that employ data assimilation and in observations by the technique of tidal deconvolution. The impact of the short-term DE3 variability in the MLT on the ionosphere and thermosphere is also clearly evident in the COSMIC and GRACE observations. Analysis of the troposphere forcing in WACCM+DART and simulations of the Global Scale Wave Model (GSWM) show that the short-term DE3 variability in the MLT is

  14. Polar Stratigraphy

    NASA Technical Reports Server (NTRS)

    1999-01-01

    These three images were taken on three different orbits over the north polar cap in April 1999. Each shows a different part of the same ice-free trough. The left and right images are separated by a distance of more than 100 kilometers (62 miles). Note the similar layers in each image.

  15. Political polarization

    PubMed Central

    Dixit, Avinash K.; Weibull, Jörgen W.

    2007-01-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality. PMID:17452633

  16. Equatorial planetary waves in the mesosphere observed by airglow periodic oscillations

    NASA Astrophysics Data System (ADS)

    Buriti, R. A.; Takahashi, H.; Lima, L. M.; Medeiros, A. F.

    Planetary scale waves in the equatorial upper mesosphere were studied by measuring the airglow OI557.7 nm, O 2b(0,1) and OH(6,2) emission intensities and OH rotational temperature at São João do Cariri (7.4°S; 36.5°W). From four years of data, 1998-2001, periodic oscillations of the airglow emissions were analyzed using the Lomb-Scargle spectral analysis. An oscillation of 3-4 days was frequently observed, which might be ultra-fast Kelvin waves. No seasonal dependency of the wave activity was found. On some occasions we found a quasi-5-day oscillation with a phase difference between the emissions, suggesting an upward energy flow. This is interpreted as a normal mode Rossby wave.

  17. Seasonal effects on distributions of minor neutral constituents in the mesosphere and lower thermosphere.

    NASA Technical Reports Server (NTRS)

    Shimazaki, T.; Laird, A. R.

    1972-01-01

    Calculations have been made of the diurnal variations in minor neutral constituents in the mesosphere and lower thermosphere for the condition of 60 deg latitude, summer and winter. Excited molecular oxygen has been added, and the effects of absorption of Schumann-Runge bands have been taken into account. The results show significant seasonal differences, which may be interpreted mainly in terms of the difference of penetration of solar radiation and the duration of sunlit hours. However, the comparison of the observed seasonal and diurnal variations in the airglow emissions from hydroxyl, atomic oxygen (5577 A), and excited molecular oxygen with those calculated from models suggests that effects of large-scale meridional circulation (horizontal and vertical transports) may be important in explaining these observations. It is shown that the concentration of the constituents whose main loss mechanism is recombination with atomic oxygen decreases sharply above 80 km.

  18. A study of mesospheric rocket contrails and clouds produced by liquid-fueled rockets

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Toon, O. B.; Whitten, R. C.; Keesee, R. G.; Hollenbach, D.

    1982-01-01

    Changes in the atmospheric composition, particularly through the condensation of rocket vehicle exhaust, caused by the flights of 400 heavy lift launch vehicles (HLLV) to carry crews and materials into space to build a satellite solar power system (SPS) were examined. Attention was given to the formation of mesospheric contrails and clouds. A one-dimensional model was used to formulate the photochemistry and vertical transport of water vapor, its nucleation into an ice cloud, and the microphysical development of the cloud. Considering one HLLV launch per day for a decade, it is projected that the upper atmosphere water vapor concentration would be increased by 10-20%, thereby augmenting the size and opacity of natural noctilucent clouds by 50%. No climatological consequences are foreseen from the clouds, although spectacular noctiluminescent cloud displays are thought to be possible.

  19. Density response of the mesospheric sodium layer to gravity wave perturbations

    NASA Technical Reports Server (NTRS)

    Shelton, J. D.; Gardner, C. S.; Sechrist, C. F., Jr.

    1980-01-01

    Lidar observations of the mesospheric sodium layer often reveal wavelike features moving through the layer. It is often assumed that these features are a layer density response to gravity waves. Chiu and Ching (1978) described the approximate form of the linear response of atmospheric layers to gravity waves. In this paper, their results are used to predict the response of the sodium layer to gravity waves. These simulations are compared with experimental observations and a good correlation is found between the two. Because of the thickness of the sodium layer and the density gradients found in it, a linear model of the layer response is not always adequate to describe gravity wave-sodium layer interactions. Inclusion of nonlinearities in the layer response is briefly discussed. Experimental data is seen to contain features consistent with the predicted nonlinearities.

  20. Solar Mesosphere Explorer satellite measurements of el Chichon stratospheric aerosols. 1: Cloud morphology

    NASA Technical Reports Server (NTRS)

    Rusch, D. W.; Clancy, R. T.; Eparvier, F. G.; Thomas, G. E.; Thomas, R. J.

    1994-01-01

    Data from the Solar Mesosphere Explorer (SME) is used to track the time, latitude, and altitude (above 18 km) development of the aerosol cloud injected into the stratosphere by the eruption of el Chichon. This unique data set, using scattering data from the near-infrared (1.27 and 1.87 microns) and visible (440 nm) spectrometers on SME, covers the period from the initial injection in April 1982 through the end of 1986. Although the bulk of the mass is contained in the latitude band from 10 deg S to 30 deg N for the entire duration of the measurements, transport of material to high latitudes is apparent in the data in the post eruption period. The times aerosol density maxima vary greatly as a function of altitude and latitude.

  1. Mesospheric nightglow spectral survey taken by the ISO spectral spatial imager on ATLAS 1

    NASA Technical Reports Server (NTRS)

    Owens, J. K.; Torr, D. G.; Torr, M. R.; Chang, T.; Fennelly, J. A.; Richards, P. G.; Morgan, M. F.; Baldridge, T. W.; Fellows, C. W.; Dougani, H.

    1993-01-01

    This paper reports the first comprehensive spectral survey of the mesospheric airglow between 260 and 832 nm taken by the Imaging Spectrometric Observatory on the ATLAS 1 mission. We select data taken in the spectral window between 275 and 300 nm to determine the variation with altitude of the Herzberg I bands originating from the vibrational levels v-prime = 3 to 8. These data provide the first spatially resolved spectral measurements of the system. The data are used to demonstrate that to within an uncertainty of +/- 10 percent, the vibrational distribution remains invariant with altitude. The deficit reported previously for the v-prime = 5 level is not observed although there is a suggestion of depletion in v-prime = 6. The data could be used to place tight constraints on the vibrational dependence of quenching rate coefficients, and on the abundance of atomic oxygen.

  2. Mesospheric nightglow spectral survey taken by the ISO spectral spatial imager on Atlas 1

    NASA Technical Reports Server (NTRS)

    Owens, J. K.; Torr, D. G.; Torr, M. R.; Chang, T.; Fennelly, J. A.; Richards, P. G.; Morgan, M. F.; Baldridge, T. W.; Dougani, H.; Swift, W.

    1993-01-01

    This paper reports the first comprehensive spectral survey of the mesospheric airglow between 260 and 832 nm taken by the Imaging Spectrometric Observatory (ISO) on the ATLAS I mission. We select data taken in the spectral window between 275 and 300 nm to determine the variation with altitude of the Herzberg I bands originating from the vibrational levels v' = 3 to 8. These data provide the first spatially resolved spectral measurements of the system. The data are used to demonstrate that to within an uncertainty of + 10%, the vibrational distribution remains invariant with altitude. The deficit reported previously for the v' = 5 level is not observed although there is a suggestion of depletion in v' = 6. The data could be used to place tight constraints on the vibrational dependence of quenching rate coefficients, and on the abundance of atomic oxygen.

  3. A further study of gravity wave induced drag and diffusion in the mesosphere

    NASA Technical Reports Server (NTRS)

    Holton, J. R.; Zhu, X.

    1984-01-01

    Lindzen's (1967) parameterization for the drag and eddy diffusion produced by breaking internal gravity waves in the mesosphere and lower thermosphere is applied to a modified version of the beta-plane channel model of Holton (1982) in which an isotropic source spectrum of waves is specified similar to that given in 1982 by Matsuno (1982). The transmission for each wave component is influenced by Newtonian cooling and by eddy diffusion induced by the breaking of other wave components. In general the waves with smallest Doppler-shifted phase speeds break first and produce sufficient eddy diffusion to significantly raise the breaking heights for the higher speed components. Thus, the wave drag and diffusion is spread through a deep layer and the resulting mean wind profiles for both summer and winter solstice conditions are more realistic than those computed previously by Holton.

  4. Properties of water vapor relevant to its measurement in the stratosphere and mesosphere

    NASA Technical Reports Server (NTRS)

    Longbothum, R. L.

    1974-01-01

    The literature on the concentrations of water vapor in the stratosphere and mesosphere was studied. It is estimated that the concentrations in these lie in the range from 0.1 ppm to 10 ppm. A survey was made of the scattering and radiative transfer properties of water vapor and the background constituents to determine the physical properties of importance to measurements of concentrations. It was determined that absorption and emission properties provide significant increases in sensitivity compared with the various scattering phenomena considered. Microwave absorption in the region of 22 GHz and 183 GHz and infrared absorption in the vibrational rotational band systems seem to be the most attractive techniques. Various experimental configurations are analyzed and compared.

  5. A global analysis of the ozone deficit in the upper stratosphere and lower mesosphere

    NASA Technical Reports Server (NTRS)

    Eluszkiewicz, Janusz; Allen, Mark

    1993-01-01

    The global measurements of temperature, ozone, water vapor, and nitrogen dioxide acquired by the Limb Infrared Monitor of the Stratosphere (LIMS), supplemented by a precomputed distribution of chlorine monoxide, are used to test the balance between odd oxygen production and loss in the upper stratosphere and lower mesosphere. An efficient photochemical equilibrium model, whose validity is ascertained by comparison with the results from a fully time-dependent one-dimensional model at selected latitudes, is used in the calculations. The computed ozone abundances are systematically lower than observations for May 1-7, 1979, which suggests, contrary to the conclusions of other recent studies, a real problem in model simulations of stratospheric ozone.

  6. Characteristics of Thunderstorms and Lightning Flashes Which Produce Mesospheric Transient Luminous Events

    NASA Technical Reports Server (NTRS)

    Lyons, W. A.; Nelson, T. E.; Armstrong, R. A.; Williams, E. R.; Suszcynsky, D. M.; Strabley, R.; Taylor, M.; Gardner, L.

    1999-01-01

    A six year record of optical observations of lightning-induced mesospheric transient luminous events (TLEs) is available from the Yucca Ridge Field Station (YRFS) near Ft. Collins, CO. Climatological analyses reveal sprites and elves occur in a variety of convective storm types, but principally mesoscale convective systems (MCSs) and squall lines. Severe supercell storms rarely produce TLEs, except during their dissipating stage. Few TLEs are observed during storms with radar echo areas <7,500 sq km. Above this size there is a modest correlation with radar areal coverage. A typical High Plains storm produces 45 TLEs over a 143 interval. Sprites and most elves are associated with +CGs. The probability of a TLE increases with peak current. In six storms, 5.1% of +CGs produced TLEs, the number increasing to 32% of +CGs with >75 kA and 52% of +CGs with >100 kA peak current.

  7. Payload charging events in the mesosphere and their impact on Langmuir type electric probes

    NASA Astrophysics Data System (ADS)

    Bekkeng, T. A.; Barjatya, A.; Hoppe, U.-P.; Pedersen, A.; Moen, J. I.; Friedrich, M.; Rapp, M.

    2013-02-01

    Three sounding rockets were launched from Andøya Rocket Range in the ECOMA campaign in December 2010. The aim was to study the evolution of meteoric smoke particles during a major meteor shower. Of the various instruments onboard the rocket payload, this paper presents the data from a multi-Needle Langmuir Probe (m-NLP) and a charged dust detector. The payload floating potential, as observed using the m-NLP instrument, shows charging events on two of the three flights. These charging events cannot be explained using a simple charging model, and have implications towards the use of fixed bias Langmuir probes on sounding rockets investigating mesospheric altitudes. We show that for a reliable use of a single fixed bias Langmuir probe as a high spatial resolution relative density measurement, each payload should also carry an additional instrument to measure payload floating potential, and an instrument that is immune to spacecraft charging and measures absolute plasma density.

  8. Annual and Semi-Annual Temperature Oscillations in the Upper Mesosphere

    NASA Technical Reports Server (NTRS)

    Niciejewski, R. J.; Killeen, T. L.

    1995-01-01

    Fourier transform spectrometer observations of the mesosphere have been performed at the University of Michigan (latitude: 42.5 N) on a long term basis. A database of near infrared Meinel hydroxyl spectra has been accumulated from which rotational temperatures have been determined. Harmonic analysis of one-day averaged temperatures for the period 1992.0 to 1994.5 has shown a distinct annual and semi-annual variation. Subsequent fitting of a five term periodic function characterizing the annual and semi-annual temperature oscillations to the daily averaged temperatures was performed. The resultant mean temperature and the amplitudes and phases of the annual and semi-annual variations are shown to coincide with an emission height slightly above 85 km which is consistent with the mean rocket derived altitude for peak nocturnal hydroxyl emission.

  9. Retrieval of metal atom and ion number densities in the mesosphere and lower thermosphere

    NASA Astrophysics Data System (ADS)

    Langowski, Martin; Von Savigny, Christian; Burrows, John

    2016-07-01

    When meteoroids enter the Earth's atmosphere with velocities of several 10 km/s, they heat up due to frictional heating and meteoric material is ablated in the upper atmosphere at around 100 km. A certain part of this ablated material are metal atoms and ions, which form layers of about 10 km width at altitudes between 80 to 110 km. The metal atoms and ions are strong emitters of dayglow coming from resonance fluorescence. From satellite observations of these emission signature, densities of the metal atom and ion layers can be retrieved. From the densities of the metal layers in combination with model simulations the input rate of meteoric material can be estimated, which still shows a large uncertainty range between 1 to 300 tons per day. We will present results of the number density retrievals from the SCIAMACHY limb mesosphere and lower thermosphere measurements from 2008 to 2012 for Mg, Mg^{+} and Na.

  10. Stratospheric and mesospheric concentric gravity waves over tropical cyclone Mahasen: Joint AIRS and VIIRS satellite observations

    NASA Astrophysics Data System (ADS)

    Yue, Jia; Miller, Steven D.; Hoffmann, Lars; Straka, William C.

    2014-11-01

    We report on the first simultaneous spaceborne observations of concentric gravity wave patterns in the stratosphere and mesosphere over the Indian Ocean excited by Tropical Cyclone Mahasen. On the nights of 13-14 May 2013, concentric ring patterns in nightglow were observed in close-proximity to Mahasen by the Day/Night Band (DNB) of the Visible/Infrared Imager/Radiometer Suite (VIIRS) on the Suomi NPP satellite. The waves exhibited horizontal wavelengths of 40-60 km. On 13 May 2013, long concentric waves of ~500 km wavelength were also seen west of India, far away (~1500 km) from their estimated center near Mahasen. Concentric gravity waves in the stratosphere were observed nearly simultaneously by the Atmospheric Infrared Sounder on the Aqua satellite. These multi-level observations provide a clearer picture of the complex three-dimensional structure of tropical cyclone-generated gravity waves than a single instrument alone.

  11. Measurement of mesospheric winds using the Michelson Interferometer for Airglow Dynamics Imaging (MIADI)

    NASA Astrophysics Data System (ADS)

    Langille, Jeffery; Ward, William E.; Nakamura, Takuji

    MIADI images the wind and irradiance fields present in mesospheric airglow signatures using a new implementation of the field widened Michelson technique. The system is unique in its ability to image the mean wind and irradiance as well as the perturbation quantities, allowing for unambiguous gravity wave parameters to be derived using a single optical element. MIADI was installed and tested at the MU radar field site in Shigaraki Japan in 2009. Several nights of observations have been obtained and the initial analysis has been completed. In this presentation, the instrument technique, calibration process and installation/testing will be described and the analysis of the initial wind and irradiance measurements will be presented.

  12. Photochemical response of the nighttime mesosphere to electric field heating—Recovery of electron density enhancements

    NASA Astrophysics Data System (ADS)

    Kotovsky, D. A.; Moore, R. C.

    2016-02-01

    A photochemical model has been developed to examine the response of the nighttime mesosphere to electric field heating. Time dynamics of 29 chemical species are accounted for by a set of 156 reactions. Recovery dynamics of electron density enhancements are examined in detail, and the recovery timescales of VLF scattering resulting from the modeled conductivity changes are quantitatively estimated. Both typical recovery (up to 240 s) and long recovery (>300 s) timescales of early VLF scattering events are explainable in terms of the model results. Electron production and loss during recovery is determined by a small set of attachment, detachment, and recombination processes. Based on the model results, we conclude that long recovery VLF scattering proceeds from sufficiently large electron density enhancements that are controlled by slow recombination loss (i.e., when attachment loss is small or balanced by detachment).

  13. Diurnal CO variations in the Venus mesosphere from CO microwave spectra

    NASA Technical Reports Server (NTRS)

    Clancy, R. T.; Muhleman, D. O.

    1985-01-01

    Microwave spectra of CO in the Venus mesosphere were measured and analyzed in order to provide mixing profiles. The results indicate that there is a significant dependence of the observed spectra on the phase of Venus. This dependence is tied to a diurnal variation in the vertical profile of CO mixing ratios with the local solar zenith angle. Spectra of the nightside hemisphere are characterized by very little absorption in the wings of the spectra, yet very deep absorption in the line center. Dayside spectra exhibit considerably greater absorption in the line wings and less absorption in the line center. Solutions for the CO mixing profile derived from spectra show that the nightside atmosphere contains two to four times the CO abundance above about 95 km relative to the dayside atmosphere above 95 km. Conversely, the dayside atmosphere between 80 and 90 km shows two to four times the CO abundance for the same altitude region in the nightside atmosphere.

  14. Flight experience of solar mesosphere explorer's power system over high temperatures ranges

    NASA Technical Reports Server (NTRS)

    Faber, Jack; Hurley, Daniel

    1987-01-01

    The performance of the power system on the Solar Mesosphere Explorer (SME) satellite for the life of the mission and the techniques used to ensure power system health are summarized. Early in the mission high cell imbalances in one of the batteries resulted in a loading scheme which attempted to minimize the cell imbalances without causing an undervoltage condition. A short term model of the power system allowed planners to predict depth of discharge using the latest available data. Due to expected orbital shifts the solar arrays experience extended periods of no eclipse. This has required special conditioning schemes to keep the batteries healthy when the eclipses return. Analysis of the SME data indicates long term health of the SME power system as long as the conditioning scheme is continued.

  15. Infra-red Radiative Cooling/heating Of The Mesosphere/lower Thermosphere

    NASA Astrophysics Data System (ADS)

    Kutepov, A. A.; Gusev, O. A.; Kaufmann, M.; Grossmann, K. U.; Feofilov, A. G.

    The new model of radiative cooling/heating of the mesosphere and lower thermo- sphere (MLT) in the ro-vibrational bands of atmospheric gases (CO2, O3, H2O, CO, NO, N2O and other) accounts for vibrational and rotational non­LTE, line- overlapping, and absorption and transformation of the near-infrared solar radiation. The model utilizes "accelerated lambda-iteration" (ALI) technique for the solution of the system of kinetic equations and the "discontinuous finite elements" (DFE) radia- tive transfer algorithm. The contributions of various band to the total cooling/heating are analyzed. The model is applied to the calculation of the MLT cooling/heating for atmospheric data retrieved from the CRISTA limb radiance measurements. Implica- tions for modeling of the MLT region are discussed.

  16. Diurnal Changes of The Ion Densities In The Undisturbed Mesosphere and Lower Thermosphere

    NASA Astrophysics Data System (ADS)

    Kazil, J.; Kopp, E.; Chabrillat, S.; Bishop, J.

    Ions are produced in the undisturbed atmosphere by solar X-ray and EUV radiation and by Galactic Cosmic Rays. The production from cosmic rays is constant throughout the day, whereas the production from solar radiation depends on the solar zenith angle. In addition, direct sunlight interacts with the ions and affects the ion chemistry. At night, below approximately 80km, there is no significant contribution to the ion production from solar light. Above this level (up to approximately 160km), scattered solar Lyman- and - radiation is the main nighttime source for ions. We use the University of Bern Atmospheric Ion Model (UBAIM), fed with neutral data from the NCAR SOCRATES model, with solar flux data from the SOLAR2000 model, and with numerical nighttime Lyman- and - fluxes to investigate the diurnal changes of the ion densities in the undisturbed mesosphere and lower thermosphere (50-120km log-p altitude).

  17. On recent interannual variability of the Arctic winter mesosphere: Implications for tracer descent

    NASA Astrophysics Data System (ADS)

    Siskind, David E.; Eckermann, Stephen D.; Coy, Lawrence; McCormack, John P.; Randall, Cora E.

    2007-05-01

    Observations from the Sounding of the Atmosphere with Broadband Emission Radiometry (SABER) experiment on the NASA/Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite show an unusual vertical displacement of the winter Arctic stratopause in 2006 with zonal mean temperatures at 0.01 hPa (~78 km) exceeding 250 K. By contrast, at the conventional stratopause location near 0.7 hPa (~50 km), temperatures were unusually cold. Simulations with the NOGAPS-ALPHA model suggest that these are coupled to an unusually warm and disturbed lower stratosphere that filtered out many of the gravity waves that normally break at and above 50 km. The model also shows that downward transport in the 2006 Arctic vortex was enhanced relative to 2005. These results might explain observations of enhanced upper atmospheric NO descending to the upper stratosphere in 2006 and highlights the importance of gravity waves in modulating the coupling of the upper atmosphere with the stratosphere.

  18. An analysis at mesospheric coherent-scatter power enhancements during solar flare events

    NASA Technical Reports Server (NTRS)

    Parker, J.; Bowhill, S. A.

    1986-01-01

    Solar flares produce increases in coherent-scatter power from the mesosphere due to the increase in free electrons produced by X-ray photoionization. Thirteen such power enhancements were observed at Urbana. When such an enhancement occurs at an altitude containing a turbulence layer with constant strength, the relative enhancement of electon density is estimated from the enhancement in power. Such estimates of enchanced electron density are compared with estimates of the X-ray photoionization at that altitude, deduced from geostationary satellite measurements. It is found that possible types ion-chemical reaction scheme may be distinguished, and the nonflare ion-pair production function may be estimated. The type of ion-chemical scheme and the nonflare ion-production function are shown to depend on the solar zenith angle.

  19. Characterization of SO2 abundance in Venus' night-side mesosphere from SPICAV/VEX observations

    NASA Astrophysics Data System (ADS)

    Belyaev, Denis; Fedorova, Anna; Piccialli, Arianna; Marcq, Emmanuel; Montmessin, Franck; Bertaux, Jean-Loup; Evdokimova, Daria

    Sulfur dioxide (SO _{2}) is a key component of Venus’ atmosphere since the planet is totally covered by H _{2}SO _{4} droplets clouds at altitudes 50-70 km. Any significant change in the SO _{x} oxides above and within the clouds affects the photochemistry in the mesosphere (70-120 km). Recent continuous observations from the Venus Express orbiter (Belyaev et al., 2012; Marcq et al., 2013) and ground-based telescopes (Sandor et al., 2010; Krasnopolsky, 2010; Encrenaz et al., 2012) showed high variability of SO _{2} abundance with years, diurnal time and latitude on the day-side and terminators (commonly from 20 to 500 ppbv above the clouds). In the night-side mesosphere SO _{2} is not photo dissociative but, so far, its behavior has never been explored in details. In this paper we present first results from sulfur dioxide observations made by SPICAV UV spectrometer onboard Venus Express orbiter in regime of stellar occultation (Bertaux et al., 2007). In this mode the instrument observes night-side mesosphere and can register SO _{2} absorption bands in 190-220 nm and CO _{2} bands in 120-200 nm at altitudes from 85 to 110 km (spectral resolution is ˜2 nm). As a result, vertical distribution of SO _{2} and CO _{2} concentrations has been retrieved in observation period from June 2006 to April 2012, at latitude range 60(°) S-60(°) N and Venus local time 20:00-04:00. On the average, mixing ratio of sulfur dioxide fluctuates around ˜100 ppbv along altitude range 90-100 km. Our work is supported by the Program №22 of RAS and grant of the Russian Government to MIPT. References: Belyaev D. et al., 2012. Vertical profiling of SO _{2} and SO above Venus' clouds by SPICAV/SOIR solar occultations. Icarus 217, 740-751. Bertaux J.-L. et al., 2007. SPICAV on Venus Express: three spectrometers to study the global structure and composition of Venus atmosphere. Planet. Space Sci. 55, 1673-1700. Encrenaz T. et al., 2012. HDO and SO _{2} thermal mapping on Venus: evidence for

  20. High-resolution observations of mesospheric layers with the Jicamarca VHF radar

    NASA Astrophysics Data System (ADS)

    Lehmacher, G.; Kudeki, E.; Chau, J.

    The 50-MHz Jicamarca radar in Peru 12 S 77 W is able to observe backscatter from the daytime mesosphere on any given day however the operation in this high-power mode is only possible during few days per year For 2005 and 2006 a two-year campaign is carried out to study the seasonal variations of the wind field echo structure and turbulence by allocating 3 days of observations near each solstice and equinox Doppler spectra are obtained with 1 minute and 150 meter resolution Besides measurements of the horizontal and vertical wind components and the spectral width the combination of MST and ISR modes allows the calculation of absolute reflectivity for the four beams We present an overview of the results with focus on the observation of large Kelvin-Helmholtz billows found typically in the upper region around 80 km

  1. When matter matters

    SciTech Connect

    Easson, Damien A.; Sawicki, Ignacy; Vikman, Alexander E-mail: ignacy.sawicki@uni-heidelberg.de

    2013-07-01

    We study a recently proposed scenario for the early universe:Subluminal Galilean Genesis. We prove that without any other matter present in the spatially flat Friedmann universe, the perturbations of the Galileon scalar field propagate with a speed at most equal to the speed of light. This proof applies to all cosmological solutions — to the whole phase space. However, in a more realistic situation, when one includes any matter which is not directly coupled to the Galileon, there always exists a region of phase space where these perturbations propagate superluminally, indeed with arbitrarily high speed. We illustrate our analytic proof with numerical computations. We discuss the implications of this result for the possible UV completion of the model.

  2. Global circulation, thermal structure, and carbon monoxide distribution in Venus' mesosphere in 1991

    NASA Technical Reports Server (NTRS)

    Lellouch, Emmanuel; Goldstein, Jeffrey J.; Rosenqvist, Jan; Bougher, Stephen W.; Paubert, Gabriel

    1994-01-01

    Millimeter-wave observations of CO lines have provided a detailed picture of Venus' mesosphere dynamics in 1991 from simultaneous measurements of absolute wind velocities in two layers and of temperature and CO horizontal and vertical profiles at 75-115 km. Venus' circulation at 90-110 km was characterized in 1991 by the superposition of a zonal retrograde flow and a subsolar-to-antisolar flow of approximately equal velocities, increasing from about 40 +/- 15 m/sec at 95 km to 90 +/- 15 m/sec at 105 km altitude. The magnitude of the increase of the SS-AS flow is consistent with Venus thermosphere general circulation models (VTGCM). At 105 km, the data further indicate a cos(latitude) dependence of the zonal flow and marginally suggest the presence of a poleward meridional component of 35 +/- 30 m/sec. No obvious day-to-day variations of the circulation are evident in the data at the 20 m/sec level. Thermal profiles in the low-latitude region appear to be consistent with the Pioneer Venus nightside profile, except above 110 km, where they are somewhat colder. High-latitude warming is still found, but mid-latitudes appear to be colder than the equator. The atmosphere appears to be in cyclostrophic balance up to about 105 km. The horizontal distribution of CO on Venus' nightside is essentially uniform, both in latitude and in local time. This behavior agrees with VTGCM simulations in which the zonal flow velocity is prescribed to match the observations. Comparison with previous wind measurements indicates that the zonal flow experiences dramatic long-term variations. This variability, along with short-term fluctuations of the mesospheric zonal flow (evidenced by the variability in the O2 nightglow emissions), apparently controls the CO and O2 nightglow distributions. Gravity wave activity is a plausible mechanism that can drive these variations.

  3. Dynamics of the mesosphere/lower thermosphere transition region at mid and low latitudes (Invited)

    NASA Astrophysics Data System (ADS)

    Larsen, M. F.

    2013-12-01

    The interface region between the mesosphere and lower thermosphere at mid and low latitudes remains one of the most poorly understood regions of the atmosphere. The altitude range between 90 and 110 km is characterized by rapid changes with height in the turbulence characteristics. Observational data have shown evidence for a transition from more isotropic to stratified turbulence at scales of a few hundred kilometers and, furthermore, the dominance of stratified turbulence in the region immediately above the nominal turbopause height before molecular diffusion becomes dominant. The turbulence characteristics not only influence the transport of mass, energy, and momentum, but may also affect the generation of bulk mean flows. The same region is characterized by large winds and shears. Winds similar to those that are observed are beginning to appear in general circulation models as the spatial resolution in the models improves, but the drivers for the winds are still generally unknown or poorly understood. The influence of plasma and electrodynamical processes become increasingly important with increasing height and can change the effective Coriolis force, which in turn affects planetary wave propagation. In addition, the observational evidence suggests that there is a rapid and generally unexplained increase in the magnitude of the vertical velocities across this transition region with vertical winds of 10 or more meters per second over periods of several hours. The drivers and effects of such large vertical winds are not understood at all. The unique dynamical properties of the mesosphere/lower thermosphere region will be described and arguments will be presented that critical parameters for understanding the various aspects of the dynamics of the region are the vorticity and divergence.

  4. Observation of a mesospheric front in a dual duct over King George Island, Antarctica

    NASA Astrophysics Data System (ADS)

    Bageston, J. V.; Wrasse, C. M.; Batista, P. P.; Hibbins, R. E.; Fritts, D. C.; Gobbi, D.; Andrioli, V. F.

    2011-05-01

    A mesospheric bore was observed with an all-sky airglow imager on the night of 9-10 July 2007 at Ferraz Station (62° S, 58° W), located on King George island on the Antarctic Peninsula. The observed bore propagated from southwest to northeast with a well defined wave front and a series of crests behind the main front. There was no evidence of dissipation during its propagation within the field of view. The wave parameters were obtained via a 2-D Fourier transform of the imager data providing a horizontal wavelength of 33 km, an observed period of 6 min, and a horizontal phase speed of 92 m s-1. Simultaneous mesospheric winds were measured with a medium frequency (MF) radar at Rothera Station (68° S, 68° W) and temperature profiles were obtained from the SABER instrument on the TIMED satellite. These wind and temperature profiles were used to estimate the propagation environment of the bore. A wavelet technique was applied to the wind in the plane of bore propagation at the OH emission height spanning three days centered on the bore event to define the dominant periodicities. Results revealed a dominance of near-inertial periods, and semi-diurnal and terdiurnal tides suggesting that the ducting structure enabling bore propagation occurred on large spatial scales. The observed tidal motions were used to reconstruct the winds employing a least-squares method, which were then compared to the observed ducting environment. Results suggest an important contribution of large-scale winds to the ducting structure, but with buoyancy frequency variations in the vertical also expected to be important. These results allow us to conclude that the bore was supported by a duct including contributions from both winds and temperature (or stability). A co-located airglow temperature imager operated simultaneously with the all-sky imager confirmed that the bore event was the dominant small-scale wave event during the analysis interval.

  5. Mesospheric Non-Migrating Tides Generated With Planetary Waves. 1; Characteristics

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G.; Talaat, E. L.; Porter, H. S.; Chan, K. L.

    2003-01-01

    We discuss results from a modeling study with our Numerical Spectral Model (NSM) that specifically deals with the non-migrating tides generated in the mesosphere. The NSM extends from the ground to the thermosphere, incorporates Hines' Doppler Spread Parameterization for small-scale gravity waves (GWs), and it describes the major dynamical features of the atmosphere including the wave driven equatorial oscillations (QBO and SAO), and the seasonal variations of tides and planetary waves. Accounting solely for the excitation sources of the solar migrating tides, the NSM generates through dynamical interactions also non-migrating tides in the mesosphere that are comparable in magnitude to those observed. Large non-migrating tides are produced in the diurnal and semi-diurnal oscillations for the zonal mean (m = 0) and in the semidiurnal oscillation for m = 1. In general, significant eastward and westward propagating tides are generated for all the zonal wave numbers m = 1 to 4. To identify the cause, the NSM is run without the solar heating for the zonal mean (m = 0), and the amplitudes of the resulting non-migrating tides are then negligibly small. In this case, the planetary waves are artificially suppressed, which are generated in the NSM through instabilities. This leads to the conclusion that the non-migrating tides are generated through non-linear interactions between planetary waves and migrating tides, as Forbes et al. and Talaat and Liberman had proposed. In an accompanying paper, we present results from numerical experiments, which indicate that gravity wave filtering contributes significantly to produce the non-linear coupling that is involved.

  6. The mesospheric sodium layer as a remotely, optically pumped magnetometer for investigation of Birkeland currents

    NASA Astrophysics Data System (ADS)

    Johnsen, Magnar G.; Matzka, Jürgen; Hoppe, Ulf-Peter

    2016-04-01

    By means of optical pumping, it is possible to use the naturally occurring sodium layer in the mesosphere to measure Earth's scalar magnetic field at ~90 km above ground. This is an altitude not accessible by other means than rockets, which only will provide point measurements of very short time scales. We are planning to modify the sodium lidar at ALOMAR in Northern Norway to be able, for the first time, to measure and monitor the magnetic field in situ in the high latitude mesosphere over longer time scales. The planned modifications to the lidar instrument will allow alternating between the new magnetometer mode and its present mode for atmospheric temperatures and winds. The technique, which has been proposed earlier for measurements at low or mid-latitudes for studies of Earth's internal magnetic field, will in our project be applied to high latitudes in the auroral zone. This opens for a completely new domain of measurements of externally generated geomagnetic variations related to currents in the magnetosphere-ionosphere system. In particular, we aim to measure the magnetic field variations in close vicinity to Birkeland currents associated with particle precipitation events penetrating to altitudes below 90 km and small-scale, discrete auroral arcs. It is, furthermore, anticipated that it will be possible to detect horizontal current structures in the E-layer on much smaller length scales than it is presently possible from ground observations alone. During the project we plan take advantage of the rich space science infrastructure located in northern Norway, including ALOMAR, EISCAT and the Tromsø Geophysical Observatory magnetometer network. If possible, we also aim to make measurements in conjunction with overpasses of the SWARM satellites.

  7. Preliminary measurements of mesospheric OH X[sup 2][Pi] by ISO on ATLAS 1

    SciTech Connect

    Morgan, M.F.; Torr, D.G. ); Torr, M.R. )

    1993-03-19

    The hydrosyl radical is a trace constituent of prime importance in photochemistry throughout the lower and middle atmosphere. It is central to oxidation chemistry in the troposphere. In the lower stratosphere, it contributes to the catalytic destruction of ozone. Perhaps most importantly in the stratosphere, OH mediates the partitioning of chlorine and nitrogen compounds, which also catalyze ozone destruction, between active radicals and inactive reservoirs. Resonance fluorescence of the OH radical was observed in the mesosphere by the Imaging Spectrometric Observatory (ISO) on ATLAS 1. A preliminary determination of the OH density profile from 70 to 80 km has been made from these observations. This marks the first measurement of ground state OH in the mesosphere since Anderson's [1971a,b] sounding rocket measurements, and the first from space. ISO imaged resonance scattered sunlight in the OH A[sup 2][Sigma]-X[sup 2][Pi](0,0) band during limb scans at tangent heights between 60 and 85 km, at 1.6 km spatial resolution, using an f/3.5 diffraction grating spectrometer with spectral resolution of 0.5 [Angstrom]. OH observations were conducted throughout most of the dayside passes during the mission, covering much of the northern hemisphere to 57[degrees]N latitude. Here the authors report results from an observation at 39[degrees]N, local solar time 13:15, on March 30, 1992; they find OH densities on the order of 8 [times] 10[sup 6] cm[sup [minus]3] from 70 to 80 km, decreasing rapidly above 80 km. 18 refs., 2 figs.

  8. Observations of Altitude Dependence and Temporal Variation of ClO in the Venus Mesosphere

    NASA Astrophysics Data System (ADS)

    Sandor, Brad J.; Clancy, R. Todd

    2015-11-01

    Analysis of the first observations of ClO in the Venus mesosphere indicate ClO is present above 85 +/-3 km altitude and not below. The retrieved nightside mean abundances show a factor of 2 decrease between observation dates Oct. 23 and Nov. 11, 2015, with change between the two dates evident at more than two sigma confidence. Abundances and altitude distributions are retrieved from submm spectroscopic observations of the 352.88 GHz line of 35ClO (made with the James Clerk Maxwell Telescope - JCMT - located an Mauna Kea, Hawaii).Detection of ClO in the Venus atmosphere confirms a theory put forward by Yung and DeMore (1982) that the Venus atmosphere is stabilized as CO2 due to chlorine catalytic recombination of CO and O. (Without some form of catalysis, the Venus atmosphere would have 10s of percent CO and O2, but it is in fact 97% CO2 and 3% N2, with only trace amounts of CO and O2.) Detailed retrieval of ClO abundances and altitude distributions (the focus of this talk) provides greater insight to the catalytic process, and to other aspects of Venus atmospheric chlorine chemistry. We compare findings of our quantitave retrieval with predictions of photochemical models, and discuss the implications for chlorine photochemisty of the Venus atmosphere. We also discuss retrieved ClO temporal variation with that of upper mesospheric HCl (Sandor and Clancy, 2012).[We acknowledge funding of this project by NASA grants NNX10AB33G, NNX12AI32G, and NNX14AK05G, as well as NSF grant AST-1312985.

  9. Mesospheric CO2 Clouds at Mars: Seven Martian Years Survey by OMEGA/MEX

    NASA Astrophysics Data System (ADS)

    Gondet, Brigitte; Bibring, Jean-Pierre

    2016-04-01

    Mesospheric clouds have been detected first from Earth (Bell et al 1996 [1]), then from Mars orbit (MGS/TES and MOC, Clancy et al 1998 [2]). Their composition (CO2) was inferred from temperature. Similar detection and temperature-inferred composition was then performed by Spicam and PFS on board Mars Express (Monmessin et al [3], Formisano et al [4]. 2006). The first direct detection and characterization (altitude, composition, velocity) was performed by OMEGA/ Mars Express (then coupled to HRSC/ Mars Express, and confirmed by CRISM/MRO (Montmessin et al. [5], 2007, Maattanen et al [6]. Scholten et al. [7], 2010, Vincendon et al [8], 2011). Omega is a very powerful tool for the study of CO2 clouds as it is able to unambiguously identify the CO2 composition of a cloud based on a near-IR spectral feature located at 4.26 μm [5] Therefore since the beginning of the Mars Express mission (2004) OMEGA as done a systematic survey of these mesospheric clouds. Thanks to the orbit of Mars Express, we can observe this clouds from different altitudes (from apocenter to pericenter) and at different local times. We will present the result of 7 Martians years of observations, point out a correlation with the dust activity and an irregular concentration of clouds from years to years. References [1] JF Bell. et al. JGR 1996; [2] RT Clancy et al., GRL 1998 [3] F. Montmessin et al. JGR 2006; [4] V. Formisano et al., Icarus 2006; [5] F. Montmessin et al JGR 2007 [6] A. Määttänen et al. Icarus 2010; [7] F. Scholten et al. PSS 2010; [8] M. Viencendon et al. JGR 2011

  10. An intercomparison of model ozone deficits in the upper stratosphere and mesosphere from two data sets

    NASA Astrophysics Data System (ADS)

    Siskind, David E.; Connor, Brian J.; Eckman, Richard S.; Remsberg, Ellis E.; Tsou, J. J.; Parrish, Alan

    1995-06-01

    We have co