Mesospheric bores at southern midlatitudes observed by ISS-IMAP/VISI: a first report of an undulating wave front

Abstract. Large-scale spatial structures of mesospheric bores were observed by the Visible and near-Infrared Spectral Imager (VISI) of the ISS-IMAP mission (Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere mapping mission from the International Space Station) in the mesospheric O2 airglow at 762 nm wavelength. Two mesospheric bore events in southern midlatitudes are reported in this paper: one event at 48–54∘ S, 10–20∘ E on 9 July 2015 and the other event at 35–43∘ S, 24∘ W–1∘ E on 7 May 2013. For the first event, the temporal evolution of the mesospheric bore was investigated from the difference of two observations in consecutive passes. The estimated eastward speed of the bore is 100 m s−1. The number of trailing waves increased with a rate of 3.5 waves h−1. Anticlockwise rotation with a speed of 20∘ h−1 was also recognized. These parameters are similar to those reported by previous studies based on ground-based measurements, and the similarity supports the validity of VISI observation for mesospheric bores. For the second event, VISI captured a mesospheric bore with a large-scale and undulating wave front. The horizontal extent of the wave front was 2200 km. The long wave front undulated with a wavelength of 1000 km. The undulating wave front is a new feature of mesospheric bores revealed by the wide field of view of VISI. We suggest that nonuniform bore propagating speed due to inhomogeneous background ducting structure might be a cause of the undulation of the wave front. Temperature measurements from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) onboard the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite indicated that bores of both events were ducted in a temperature inversion layer.

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Undulating wave front of mesospheric bore; Space-borne observations by ISS-IMAP/VISI

10.5194/acp-2018-383 ◽

2018 ◽

Author(s):

Yuta Hozumi ◽

Akinori Saito ◽

Takeshi Sakanoi ◽

Atsushi Yamazaki ◽

Keisuke Hosokawa

Keyword(s):

Wave Front ◽

Large Scale ◽

Near Infrared ◽

Wave Length ◽

Inversion Layer ◽

Space Station ◽

Temperature Inversion ◽

The South ◽

Broadband Emission ◽

Spectral Imager

Abstract. Large-scale spatial structures of mesospheric bores were observed by Visible and near Infrared Spectral Imager (VISI) of the ISS-IMAP mission (Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere mapping mission from the International Space Station) in the mesospheric O2 airglow at 762 nm wavelength. Two mesospheric bore events are reported in this paper; one event was observed over the south of African continent (48° S–54° S and 10° E–25° E) on 9 July 2015, and the other event over the south Atlantic Ocean (35° S–43° S and 24° W–1° E) on 7 May 2013. For the first event, the temporal evolution of the mesospheric bore was investigated from the difference of two observations in consecutive paths. The estimated eastward speed of the bore is 100 m/sec. The number of trailing waves increased with a rate of 3.5 wave/hour. Anti-clockwise rotation with a speed of 20º/hour was also recognized. These parameters are similar to those reported by previous studies based on ground-based measurements, and the similarity supports the validity of VISI observation for mesospheric bores. For the second event, VISI captured a mesopshric bore having a large-scale and undulating wave front. The horizontal extent of the wave front was 2,200 km. The long wave front undulated with 1,000 km wave length. The undulating wave front is a new feature of mesospheric bore revealed by the wide FOV of VISI. We suggest that non-uniform bore propagating speed due to inhomogeneous background ducting structure might be a cause of the undulation of the wave front. Temperature measurements from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) of the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite indicated that bores of both events were ducted in a temperature inversion layer.

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Methodology for determining multilayered temperature inversions

Atmospheric Measurement Techniques ◽

10.5194/amt-8-2051-2015 ◽

2015 ◽

Vol 8 (5) ◽

pp. 2051-2060 ◽

Cited By ~ 12

Author(s):

G. J. Fochesatto

Keyword(s):

Temperature Profile ◽

Large Scale ◽

Error Function ◽

Inversion Layer ◽

Lower Troposphere ◽

Temperature Inversion ◽

Linear Interpolation ◽

Pollution Dispersion ◽

Thermal Inversion ◽

Temperature Inversions

Abstract. Temperature sounding of the atmospheric boundary layer (ABL) and lower troposphere exhibits multilayered temperature inversions specially in high latitudes during extreme winters. These temperature inversion layers are originated based on the combined forcing of local- and large-scale synoptic meteorology. At the local scale, the thermal inversion layer forms near the surface and plays a central role in controlling the surface radiative cooling and air pollution dispersion; however, depending upon the large-scale synoptic meteorological forcing, an upper level thermal inversion can also exist topping the local ABL. In this article a numerical methodology is reported to determine thermal inversion layers present in a given temperature profile and deduce some of their thermodynamic properties. The algorithm extracts from the temperature profile the most important temperature variations defining thermal inversion layers. This is accomplished by a linear interpolation function of variable length that minimizes an error function. The algorithm functionality is demonstrated on actual radiosonde profiles to deduce the multilayered temperature inversion structure with an error fraction set independently.

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The HETDEX Instrumentation: Hobby–Eberly Telescope Wide-field Upgrade and VIRUS

The Astronomical Journal ◽

10.3847/1538-3881/ac2c02 ◽

2021 ◽

Vol 162 (6) ◽

pp. 298

Author(s):

Gary J. Hill ◽

Hanshin Lee ◽

Phillip J. MacQueen ◽

Andreas Kelz ◽

Niv Drory ◽

...

Keyword(s):

Dark Energy ◽

Large Scale ◽

Near Infrared ◽

Cosmological Parameters ◽

Resolving Power ◽

Wide Field ◽

Low Resolution ◽

Integral Field Spectrograph ◽

Optical Astronomy ◽

Integral Field

Abstract The Hobby–Eberly Telescope (HET) Dark Energy Experiment (HETDEX) is undertaking a blind wide-field low-resolution spectroscopic survey of 540 deg2 of sky to identify and derive redshifts for a million Lyα-emitting galaxies in the redshift range 1.9 < z < 3.5. The ultimate goal is to measure the expansion rate of the universe at this epoch, to sharply constrain cosmological parameters and thus the nature of dark energy. A major multiyear Wide-Field Upgrade (WFU) of the HET was completed in 2016 that substantially increased the field of view to 22′ diameter and the pupil to 10 m, by replacing the optical corrector, tracker, and Prime Focus Instrument Package and by developing a new telescope control system. The new, wide-field HET now feeds the Visible Integral-field Replicable Unit Spectrograph (VIRUS), a new low-resolution integral-field spectrograph (LRS2), and the Habitable Zone Planet Finder, a precision near-infrared radial velocity spectrograph. VIRUS consists of 156 identical spectrographs fed by almost 35,000 fibers in 78 integral-field units arrayed at the focus of the upgraded HET. VIRUS operates in a bandpass of 3500−5500 Å with resolving power R ≃ 800. VIRUS is the first example of large-scale replication applied to instrumentation in optical astronomy to achieve spectroscopic surveys of very large areas of sky. This paper presents technical details of the HET WFU and VIRUS, as flowed down from the HETDEX science requirements, along with experience from commissioning this major telescope upgrade and the innovative instrumentation suite for HETDEX.

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AN EXTREMELY DEEP, WIDE-FIELD NEAR-INFRARED SURVEY: BRIGHT GALAXY COUNTS AND LOCAL LARGE SCALE STRUCTURE

The Astrophysical Journal Supplement Series ◽

10.1088/0067-0049/186/1/94 ◽

2009 ◽

Vol 186 (1) ◽

pp. 94-110 ◽

Cited By ~ 24

Author(s):

R. C. Keenan ◽

L. Trouille ◽

A. J. Barger ◽

L. L. Cowie ◽

W.-H. Wang

Keyword(s):

Large Scale ◽

Near Infrared ◽

Large Scale Structure ◽

Scale Structure ◽

Wide Field ◽

Bright Galaxy ◽

Infrared Survey

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The distance to M31 in the era of precision cosmology

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312021473 ◽

2012 ◽

Vol 8 (S289) ◽

pp. 235-235

Author(s):

David Valls-Gabaud

Keyword(s):

Large Scale ◽

Near Infrared ◽

Hubble Space Telescope ◽

Three Dimensional ◽

Eclipsing Binaries ◽

Wide Field ◽

Acoustic Oscillations ◽

Data Set ◽

Red Giant ◽

Precision Cosmology

AbstractWith the advent of precision cosmology, where distances out to redshifts z < 0.6 can be measured to 2% precision on the basis of baryon acoustic oscillations, it appears essential to establish an accurate calibration of the primary and secondary indicators of the cosmological distance ladder. Here we review recent attempts at anchoring M31 very accurately using three independent methods, and discuss in detail the systematics that affect each. Two double-lined eclipsing binaries yield a distance to M31 which is precise to 4%. New Bayesian methods have been applied to determine the tip of the red-giant branch, even in sparsely populated colour–magnitude diagrams, and provide unique insights in the context of a precise three-dimensional distribution of the satellites in the M31 system. Over 2500 Cepheids have been identified in large-scale multi-colour surveys of M31, the largest homogeneous data set thus far obtained for any galaxy. A subset of 68 with periods longer than 10 days have been observed with the Wide-Field Camera 3 on board the Hubble Space Telescope, yielding the tightest-ever near-infrared period–luminosity relation, with a mean distance error of 1%. Combined with other measurements, the distance to M31 is now measured with a precision of 3%. Forthcoming improvements, and their implications, are also discussed.

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Large-scale dune aurora event investigation combining Citizen Scientists' photographs and spacecraft observations

10.5194/egusphere-egu21-5986 ◽

2021 ◽

Author(s):

Maxime Grandin ◽

Minna Palmroth ◽

Graeme Whipps ◽

Milla Kalliokoski ◽

Mark Ferrier ◽

...

Keyword(s):

Large Scale ◽

Inversion Layer ◽

Time Lapse ◽

Temperature Inversion ◽

Northern Europe ◽

Neutral Atmosphere ◽

The West ◽

Citizen Scientist ◽

Near Earth Space ◽

Atmospheric Wave

<p>Recently, citizen scientist photographs led to the discovery of a new auroral form called "the dune aurora" which exhibits parallel stripes of brighter emission in the green diffuse aurora at about 100 km altitude. This discovery raised several questions, such as (i) whether the dunes are associated with particle precipitation, (ii) whether their structure arises from spatial inhomogeneities in the precipitating fluxes or in the underlying neutral atmosphere, and (iii) whether they are the auroral manifestation of an atmospheric wave called a mesospheric bore. This study investigates a large-scale dune aurora event on 20 January 2016 above Northern Europe. The dunes were observed from Finland to Scotland, spanning over 1500 km for at least four hours. Spacecraft observations confirm that the dunes are associated with electron precipitation and reveal the presence of a temperature inversion layer below the mesopause during the event, creating suitable conditions for mesospheric bore formation. The analysis of a time lapse of pictures by a citizen scientist from Scotland leads to the estimate that, during this event, the dunes propagate toward the west-southwest direction at about 200 m/s, presumably indicating strong horizontal winds near the mesopause. These results show that citizen science and dune aurora studies can fill observational gaps and be powerful tools to investigate the least-known region of near-Earth space at altitudes near 100 km.</p>

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Preliminary Dual-Satellite Observations of Atmospheric Gravity Waves in Airglow

Atmosphere ◽

10.3390/atmos10110650 ◽

2019 ◽

Vol 10 (11) ◽

pp. 650

Author(s):

Jia Yue ◽

Septi Perwitasari ◽

Shuang Xu ◽

Yuta Hozumi ◽

Takuji Nakamura ◽

...

Keyword(s):

Gravity Waves ◽

Near Infrared ◽

Infrared Imaging ◽

Numerical Models ◽

Space Station ◽

Upper Atmosphere ◽

Lower Atmosphere ◽

Atmospheric Gravity Waves ◽

Spectral Imager ◽

Atmospheric Gravity

Atmospheric gravity waves (AGWs) are among the important energy and momentum transfer mechanisms from the troposphere to the middle and upper atmosphere. Despite their understood importance in governing the structure and dynamics of these regions, mesospheric AGWs remain poorly measured globally, and largely unconstrained in numerical models. Since late 2011, the Suomi National Polar-orbiting Partnership (NPP) Visible/Infrared Imaging Radiometer Suite (VIIRS) day–night band (DNB) has observed global AGWs near the mesopause by virtue of its sensitivity to weak emissions of the OH* Meinel bands. The wave features, detectable at 0.75 km spatial resolution across its 3000 km imagery swath, are often confused by the upwelling emission of city lights and clouds reflecting downwelling nightglow. The Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere (IMAP)/ Visible and near-Infrared Spectral Imager (VISI) O2 band, an independent measure of the AGW structures in nightglow based on the International Space Station (ISS) during 2012–2015, contains much less noise from the lower atmosphere. However, VISI offers much coarser resolution of 14–16 km and a narrower swath width of 600 km. Here, we present preliminary results of comparisons between VIIRS/DNB and VISI observations of AGWs, focusing on several concentric AGW events excited by the thunderstorms over Eastern Asia in August 2013. The comparisons point toward suggested improvements for future spaceborne airglow sensor designs targeting AGWs.

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DIURNAL AND SPATIAL VARIATIONS OF RADON CONCENTRATION AND ITS INFLUENCE ON IONIZATION OF AIR

Contemporary Materials ◽

10.7251/comen2001014k ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Zdenka Stojanovska ◽

Predrag Kolarž ◽

Zoran Ćurguz ◽

Zora S. Žunić

Keyword(s):

Radon Concentration ◽

Lower Layer ◽

Health Hazard ◽

Inversion Layer ◽

Atmospheric Electricity ◽

Temperature Inversion ◽

Spatial Variations ◽

Alpha Emitter ◽

Radon Monitor ◽

The Difference

The most abundant and efficient source of air ionization in the lower layer of the atmosphere is radon. As an alpha emitter, radon plays a crucial role in the earth's atmospheric electricity. Besides the physical, radon and ions have a significant biological role concerning human health: radon is a health hazard while the ions are beneficial ingredients of the air we breathe. In this study, we examined the dynamics of radon and air ions diurnal change in houses with different floor and windows insulations. Measurements were made using continual radon monitor Rad-7 and air ion counter CDI-06. Diurnal and spatial variations of both atmospheric constituents are mutually related and dependent mostly on radon exhalation potential, meteorological parameters, aerosol concentration and formation of the temperature inversion layer. Indoor concentrations are related to the potential for accumulation of radon that is coming from the ground beneath the foundation and also influenced by external radon concentration that is diffusing through the walls, doors, and windows. Level of diffusion is depending on insulation. The difference in the paths by which radon enters the home can be seen by analyzing changes during diurnal continuous measurements.

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Taxonomic classification of asteroids based on MOVIS near-infrared colors

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833023 ◽

2018 ◽

Vol 617 ◽

pp. A12 ◽

Cited By ~ 13

Author(s):

M. Popescu ◽

J. Licandro ◽

J. M. Carvano ◽

R. Stoicescu ◽

J. de León ◽

...

Keyword(s):

Large Scale ◽

Near Infrared ◽

Probabilistic Method ◽

Sloan Digital Sky Survey ◽

Taxonomic Classification ◽

Wide Field ◽

Probabilistic Algorithms ◽

Frequency Distributions ◽

Object Based

Context. The MOVIS catalog contains the largest set of near-infrared (NIR) colors for solar system objects. These data were obtained from the observations performed by VISTA-VHS survey using the Y, J, H, and Ks filters. The taxonomic classification of objects in this catalog allows us to obtain large-scale distributions for the asteroidal population, to study faint objects, and to select targets for detailed spectral investigations. Aims. We aim to provide a taxonomic classification for asteroids observed by VISTA-VHS survey. We derive a method for assigning a compositional type to an object based on its (Y − J), (J − Ks), and (H − Ks) colors. Methods. We present a taxonomic classification for 18 265 asteroids from the MOVIS catalog, using a probabilistic method and the k-nearest neighbors algorithm. Because our taxonomy is based only on NIR colors, several classes from Bus-DeMeo were clustered into groups and a slightly different notation was used: i.e., the superscript indicates that the classification was obtained based on the NIR colors and the subscript indicates possible misidentifications with other types. Our results are compared with the information provided by the Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE). Results. The two algorithms used in this study give a taxonomic type for all objects having at least (Y − J) and (J − Ks) observed colors. A final classification is reported for a set of 6496 asteroids based on the criteria that kNN and probabilistic algorithms gave the same result, and the color errors are within the limits (Y − J)err ≤ 0.118 and (J − Ks)err ≤ 0.136. This set includes 144 bodies classified as Bkni, 613 as Cni, 197 as Cgxni, 91 as Xtni, 440 as Dsni, 665 as Klni, 233 as Adni, 3315 as Sni, and 798 as Vni. We report the albedo distribution for each taxonomic group and we compute new median values for the main types. We found that V-type and A-type candidates have identical size frequency distributions, but V types are five times more common than A types. Several particular cases, such as the A-type asteroid (11616) 1996 BQ2 and the S-type (3675) Kematsch, both in the Cybele population, are discussed.

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Relationship between total plasma homocysteine and the risk of aneurysms – a meta-analysis

VASA ◽

10.1024/0301-1526/a000891 ◽

2020 ◽

pp. 1-6

Author(s):

Hanji Zhang ◽

Dexin Yin ◽

Yue Zhao ◽

Yezhou Li ◽

Dejiang Yao ◽

...

Keyword(s):

Large Scale ◽

Meta Analysis ◽

Single Species ◽

Total Plasma ◽

Control Groups ◽

Randomized Controlled ◽

Randomized Controlled Studies ◽

The Difference ◽

The Relationship ◽

Healthy Participants

Summary: Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.

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