scholarly journals ExoMars TGO/NOMAD‐UVIS vertical profiles of ozone: Part 2: The high‐altitude layers of atmospheric ozone

2021 ◽  
Author(s):  
Alain SJ. Khayat ◽  
Michael D. Smith ◽  
Michael Wolff ◽  
Frank Daerden ◽  
Lori Neary ◽  
...  
Keyword(s):  
High Altitude ◽  
Atmospheric Ozone ◽  
Vertical Profiles

scholarly journals The diurnal cycle of cloud profiles over land and ocean between 51° S and 51° N, seen by the CATS spaceborne lidar from the International Space Station

2018 ◽  
Vol 18 (13) ◽  
pp. 9457-9473 ◽  
Author(s):  
Vincent Noel ◽  
Hélène Chepfer ◽  
Marjolaine Chiriaco ◽  
John Yorks
Keyword(s):  
High Altitude ◽  
International Space Station ◽  
Diurnal Cycle ◽  
Space Station ◽  
Cloud Fraction ◽  
Vertical Profiles ◽  
Diurnal Variability ◽  
International Space ◽  
Low Level ◽  
Diurnal Cycles

Abstract. We document, for the first time, how detailed vertical profiles of cloud fraction (CF) change diurnally between 51∘ S and 51∘ N, by taking advantage of 15 months of measurements from the Cloud-Aerosol Transport System (CATS) lidar on the non-sun-synchronous International Space Station (ISS). Over the tropical ocean in summer, we find few high clouds during daytime. At night they become frequent over a large altitude range (11–16 km between 22:00 and 04:00 LT). Over the summer tropical continents, but not over ocean, CATS observations reveal mid-level clouds (4–8 km above sea level or a.s.l.) persisting all day long, with a weak diurnal cycle (minimum at noon). Over the Southern Ocean, diurnal cycles appear for the omnipresent low-level clouds (minimum between noon and 15:00) and high-altitude clouds (minimum between 08:00 and 14:00). Both cycles are time shifted, with high-altitude clouds following the changes in low-altitude clouds by several hours. Over all continents at all latitudes during summer, the low-level clouds develop upwards and reach a maximum occurrence at about 2.5 km a.s.l. in the early afternoon (around 14:00). Our work also shows that (1) the diurnal cycles of vertical profiles derived from CATS are consistent with those from ground-based active sensors on a local scale, (2) the cloud profiles derived from CATS measurements at local times of 01:30 and 13:30 are consistent with those observed from CALIPSO at similar times, and (3) the diurnal cycles of low and high cloud amounts (CAs) derived from CATS are in general in phase with those derived from geostationary imagery but less pronounced. Finally, the diurnal variability of cloud profiles revealed by CATS strongly suggests that CALIPSO measurements at 01:30 and 13:30 document the daily extremes of the cloud fraction profiles over ocean and are more representative of daily averages over land, except at altitudes above 10 km where they capture part of the diurnal variability. These findings are applicable to other instruments with local overpass times similar to CALIPSO's, such as all the other A-Train instruments and the future EarthCARE mission.

scholarly journals The role of open lead interactions in atmospheric ozone variability between Arctic coastal and inland sites

Elem Sci Anth ◽  
2016 ◽  
Vol 4 ◽  
Author(s):  
Peter K. Peterson ◽  
Kerri A. Pratt ◽  
William R. Simpson ◽  
Son V. Nghiem ◽  
Lemuel X. Pérez Pérez ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Sea Ice ◽  
Ozone Depletion ◽  
Surface Ozone ◽  
Optical Absorption Spectroscopy ◽  
Atmospheric Ozone ◽  
Vertical Profiles ◽  
Large Spatial Scale ◽  
Near Surface ◽  
Air Masses

Abstract Boundary layer atmospheric ozone depletion events (ODEs) are commonly observed across polar sea ice regions following polar sunrise. During March-April 2005 in Alaska, the coastal site of Barrow and inland site of Atqasuk experienced ODEs (O3< 10 nmol mol-1) concurrently for 31% of the observations, consistent with large spatial scale ozone depletion. However, 7% of the time ODEs were exclusively observed inland at Atqasuk. This phenomenon also occurred during one of nine flights during the BRomine, Ozone, and Mercury EXperiment (BROMEX), when atmospheric vertical profiles at both sites showed near-surface ozone depletion only at Atqasuk on 28 March 2012. Concurrent in-flight BrO measurements made using nadir scanning differential optical absorption spectroscopy (DOAS) showed the differences in ozone vertical profiles at these two sites could not be attributed to differences in locally occurring halogen chemistry. During both studies, backward air mass trajectories showed that the Barrow air masses observed had interacted with open sea ice leads, causing increased vertical mixing and recovery of ozone at Barrow and not Atqasuk, where the air masses only interacted with tundra and consolidated sea ice. These observations suggest that, while it is typical for coastal and inland sites to have similar ozone conditions, open leads may cause heterogeneity in the chemical composition of the springtime Arctic boundary layer over coastal and inland areas adjacent to sea ice regions.

Seasonal variation of ozone vertical profiles form ExoMars TGO and comparison to water

2021 ◽  
Author(s):  
Manish R. Patel ◽  
Graham Seller ◽  
Jonathon Mason ◽  
James Holmes ◽  
Megan Brown ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
High Altitude ◽  
Relative Abundance ◽  
High Latitude ◽  
Dust Storm ◽  
Trace Gas ◽  
Line Of Sight ◽  
Vertical Profiles ◽  
Elevated Ozone ◽  
Vertical Distributions

<p>The Ultraviolet and Visible Spectrometer (UVIS) channel [1] of the Nadir and Occultation for Mars Discovery (NOMAD) instrument [2] aboard the ExoMars Trace Gas Orbiter has been making observations of the vertical, latitudinal and seasonal distributions of ozone.  Here, we present ~1.5 Mars Years (MY) of vertical profiles of ozone, from <em>L</em><sub>S</sub> = 163° in MY34 to <em>L</em><sub>S</sub> = 320° in MY35.  This period includes the occurrence of the MY34 Global Dust Storm. The relative abundance of both ozone and water (from coincident NOMAD measurements) increases with decreasing altitude below ~40 km at perihelion and at aphelion, localised decreases in ozone abundance exist between 25-35 km coincident with the location of modelled peak water abundances. High latitude (> ± 55°), high altitude (40-55 km) equinoctial ozone enhancements are observed in both hemispheres (<em>L</em><sub>S</sub> ~350‑40°).  Morning terminator observations show elevated ozone abundances with respect to evening observations, most likely attributed to diurnal photochemical partitioning along the line of sight between ozone and O. The ozone retrievals presented here provide the most complete global description of Mars ozone vertical distributions to date as a function of season and latitude</p>

The high-altitude peaks of atmospheric ozone as observed by NOMAD/UVIS onboard the ExoMars Trace Gas Orbiter Mission

2021 ◽  
Author(s):  
Alain SJ Khayat ◽  
Michael D. Smith ◽  
Michael J. Wolff ◽  
Frank W. Daerden ◽  
Lori Neary ◽  
...  
Keyword(s):  
High Altitude ◽  
Trace Gas ◽  
Atmospheric Ozone ◽  
Orbiter Mission

On the detection of a high-altitude peak of atmospheric ozone by the NOMAD/UVIS onboard the ExoMars TGO

2020 ◽  
Author(s):  
Alain Khayat ◽  
Michael Smith ◽  
Michael Wolff ◽  
Frank Daerden ◽  
Manish Patel ◽  
...  
Keyword(s):  
High Altitude ◽  
General Circulation ◽  
Circulation Model ◽  
Principal Component ◽  
Martian Atmosphere ◽  
Visible Range ◽  
Atmospheric Ozone ◽  
Northern Summer ◽  
Solar Occultation ◽  
Hartley Band

<p>The Nadir and Occultation for MArs Discovery (NOMAD) is a spectrometer suite onboard the ExoMars Trace Gas Orbiter (TGO), providing observations in the nadir, limb, and solar occultation modes since April 2018. UVIS, a single spectrometer unit within NOMAD spans the ultraviolet-visible range between 200 nm and 650 nm. It obtained ~ 4000 vertically resolved (< 1 km) solar occultation observations of the martian atmosphere for over a full Mars year (MY, 687 days) starting at MY 34 during late northern summer at L<sub>s</sub> = 163°. Ozone (O<sub>3</sub>), a principal component of the martian atmosphere, is highly responsive to the incoming UV flux, and is a sensitive tracer of the odd hydrogen chemistry. Transmittance spectra returned by UVIS sampled the O<sub>3 </sub>Hartley band around 250 nm and provided unique insights into understanding the vertical, latitudinal and temporal behavior of O<sub>3</sub>. UVIS detected a high-altitude peak of O<sub>3 </sub>between 40 and 60 km that is mostly persistent between L<sub>s</sub> = 340° and ~ 200° at polar latitudes, and is found to be highly dependent on latitude and season. We will present high-resolution results tracking the vertical, latitudinal, diurnal and seasonal evolution of the secondary peak of ozone for a full Mars year. In comparison, we will also provide O<sub>3</sub> simulations from the GEM-Mars General Circulation Model (GCM) with the purpose of shedding light into understanding the photochemical processes that lead to the presence and disappearance of the high-altitude peak of atmospheric ozone. </p>

scholarly journals The diurnal cycle of cloud profiles over land and ocean between 51° S and 51° N, seen by the CATS spaceborne lidar from the International Space Station

2018 ◽  
Author(s):  
Vincent Noel ◽  
Hélène Chepfer ◽  
Marjolaine Chiriaco ◽  
John Yorks
Keyword(s):  
High Altitude ◽  
International Space Station ◽  
Diurnal Cycle ◽  
Space Station ◽  
Cloud Fraction ◽  
Vertical Profiles ◽  
Diurnal Variability ◽  
International Space ◽  
Diurnal Cycles ◽  
High Clouds

Abstract. We take advantage of 15 months of measurements from the Cloud and Aerosol Transport System (CATS) lidar on the non-sun-synchronous International Space Station (ISS) to document, for the first time, the diurnal cycle of detailed vertical profiles of Cloud Fraction between 51° S and 51° N. After processing CATS lidar data, we analyzed the diurnal cycles of the cloud profiles over ocean and over continent in two different seasons. Over the Tropical ocean in summer, the high clouds geometric thickness increases significantly from 1 km near 5 PM to 5 km near 10 PM, resulting in a high clouds maximum at nighttime. Over the summer tropical continents, CATS observations reveal the presence of a mid-level cloud layer (4–8 km ASL) persisting all-day long, with a weak diurnal cycle (minimum at noon). Over the Southern Ocean, diurnal cycles appear for the omnipresent low-level clouds (minimum between noon and 3 PM) and for the high-altitude clouds (minimum between 8 AM and 2 PM). Both cycles are time-shifted, with high-altitude clouds following the changes in low-altitude clouds by several hours. Over all continents at all latitudes during summer, the low-level clouds develop vertically and reach a maximum occurrence at about 2.5 km ASL in the early afternoon (around 2 pm). Our work also show that 1) the diurnal cycles of vertical profiles derived from CATS are consistent with those from ground-based active sensors at local scale, 2) the cloud profiles derived from CATS measurements at local times of 0130 AM and 0130 PM are consistent with those observed from CALIPSO at similar times, 3) the diurnal cycles of low and high cloud amounts derived from CATS are in general in phase with those derived from geostationary imagery but less pronounced. Finally, the diurnal variability of cloud profiles revealed by CATS strongly suggests that CALIPSO measurements at 0130 AM and PM document the daily extremes of the cloud fraction profiles over ocean and are more representative of daily averages over land, except at altitudes above 10 km where they capture part of the diurnal variability. These findings are equally applicable to other instruments with local overpass times similar to CALIPSO's, like all the other A-Train instruments and the future Earth-CARE mission.

Contrast of Filament Bright Rims

1994 ◽  
Vol 144 ◽  
pp. 365-367
Author(s):  
E. V. Kononovich ◽  
O. B. Smirnova ◽  
P. Heinzel ◽  
P. Kotrč
Keyword(s):  
High Altitude ◽  
Line Profile ◽  
Line Center ◽  
Magnetic Structures ◽  
The Mean

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.

Clean Electron Microscope Substrate Films Used for Micrometeorite Collection and Study

1967 ◽  
Vol 25 ◽  
pp. 366-367
Author(s):  
D. M. Davies ◽  
R. Kemner ◽  
E. F. Fullam
Keyword(s):  
Thin Film ◽  
Electron Microscope ◽  
High Altitude ◽  
Amyl Acetate ◽  
Temperature Variations ◽  
Film Forming ◽  
Film Specimen ◽  
Particulate Contaminants

All serious electron microscopists at one time or another have been concerned with the cleanliness and freedom from artifacts of thin film specimen support substrates. This is particularly important where there are relatively few particles of a sample to be found for study, as in the case of micrometeorite collections. For the deposition of such celestial garbage through the use of balloons, rockets, and aircraft, the thin film substrates must have not only all the attributes necessary for use in the electron microscope, but also be able to withstand rather wide temperature variations at high altitude, vibration and shock inherent in the collection vehicle's operation and occasionally an unscheduled violent landing.Nitrocellulose has been selected as a film forming material that meets these requirements yet lends itself to a relatively simple clean-up procedure to remove particulate contaminants. A 1% nitrocellulose solution is prepared by dissolving “Parlodion” in redistilled amyl acetate from which all moisture has been removed.

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