| Consequences of Recent Southern Hemisphere Winter Variability on Polar Mesospheric Clouds |
Jan 2011 |
10 pages |
| Authors:
David E Siskind; Michael H Stevens; Mark Hervig; Fabrizio Sassi; Karl Hoppel; Christoph R Englert; Andrew J Kochenash; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
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 | Variations in the Southern Hemisphere (SH) winter of 2007, 2008 and 2009 had important consequences on polar mesospheric clouds (PMCs) observed in the corresponding Northern summers. Specifically, the stratospheric SH winter of 2007 was observed to be warmer than in 2008 and 2009. Using the high altitude analysis from the Navy Operational Global Atmospheric Prediction System- Advanced Level Physics High Altitude (NOGAPS-ALPHA) forecast/assimilation system we show that this warmth was ... |
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| Spatial Heterodyne Imager for Mesospheric Radicals on STPSat-1 |
22 Oct 2010 |
21 pages |
| Authors:
Christoph R Englert; Michael H Stevens; David E Siskind; John M Harlander; Frederick L Roesler; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
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| The Spatial Heterodyne Imager for Mesospheric Radicals (SHIMMER) was a high-resolution, near ultraviolet spectrometer that imaged the Earth's limb for 2.5 years between March 2007 and October 2009. The instrument used the Spatial Heterodyne Spectroscopy technique for the first time on a satellite and successfully demonstrated its capabilities. SHIMMER measured the solar resonance fluorescence of the OH A(squared)Sum(-X(squared)Pi) (0, 0) band around 309 nanometers, which allows the retrieval of mesospheric ... |
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| Tidally Induced Variations of PMC Altitudes and Ice Water Content Using a Data Assimilation System |
Apr 2010 |
45 pages |
| Authors:
Michael H Stevens; David E Siskind; Stephen D Eckermann; Lawrence Coy; John P McCormack; Christoph R Englert; Karl W Hoppel; Kin Nielsen; Andrew J Kochenash; Mark E Hervig; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
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| A variety of space-borne experiments have observed polar mesospheric clouds (PMC) since the late 20th century. Many of these experiments are on satellites in sun-synchronous orbits and therefore allow observations only at fixed local times (LT). Temperature oscillations over the diurnal cycle are an important source of PMC variability. In order to quantify long-term natural or anthropogenic changes in PMCs it is therefore essential to understand their variation over the ... |
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| Tidally Induced Variations of Polar Mesospheric Cloud Altitudes and Ice Water Content using a Data Assimilation System |
Jan 2010 |
14 pages |
| Authors:
Michael H Stevens; David E Siskind; Stephen D Eckermann; Lawrence Coy; John P McCormack; Christoph R Englert; Karl W Hoppel; Kim Nielsen; Andrew J Kochenash; Mark E Hervig; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
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| A variety of spaceborne experiments have observed polar mesospheric clouds (PMC) since the late 20th century. Many of these experiments are on satellites in Sunsynchronous orbits and therefore allow observations only at fixed local times (LT). Temperature oscillations over the diurnal cycle are an important source of PMC variability. In order to quantify long-term natural or anthropogenic changes in PMCs, it is therefore essential to understand their variation over the ... |
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| High-Altitude Data Assimilation System Experiments for the Northern Summer Mesosphere Season of 2007 |
Jan 2009 |
22 pages |
| Authors:
Stephen D Eckermann; Karl W Hoppel; Lawrence Coy; John P McCormack; David E Siskind; Kim Nielsen; Andrew Kochenash; Michael H Stevens; Christoph R Englert; Werner Singer; NAVAL RESEARCH LAB WASHINGTON DC
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| A global numerical weather prediction system is extended to the mesosphere and lower thermosphere (MLT) and used to assimilate high-altitude satellite measurements of temperature, water vapor and ozone from MLS and SABER during May-July 2007. Assimilated temperature and humidity from 100 to 0.001 hPa show minimal biases compared to satellite data and existing analysis fields. Saturation ratiosderived diagnostically from these assimilated temperature and water vapor fields at PMC altitudes and ... |
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| First Results From the Spatial Heterodyne Imager for Mesospheric Radicals (SHIMMER): Diurnal Variation of Mesospheric Hydroxyl |
08 Oct 2008 |
6 pages |
| Authors:
Christoph R Englert; Michael H Stevens; David E Siskind; John M Harlander; Fred L Roesler; Herbert M Pickett; Christian von Savigny; Andrew J Kochenash; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
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| We present the first SHIMMER observations of the diurnal variation of mesospheric hydroxyl (OH). We compare our data with Aura Microwave Limb Sounder (MLS) observations at about 13h local time near 55N and find very good agreement. This validates the Spatial Heterodyne Spectroscopy technique for space-borne optical remote sensing applications. We extend our analysis to other local times, not observed by MLS, for latitudes near 55N in the summer of ... |
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| First UV Satellite Observations of Mesospheric Water Vapor |
21 Jun 2008 |
15 pages |
| Authors:
Michael H Stevens; R L Gattinger; J Gumbel; E J Llewellyn; D A Degenstein; M Khaplanov; G Witt; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
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| We report the first UV satellite observations of mesospheric water vapor. The measurements are of nonthermal OH prompt emission between 300-330 nm produced directly from the photodissociation of water vapor by H Lyman-alpha. This technique is most sensitive to water vapor concentrations between 70-90 km altitude. We present OH data from two limb scanning experiments: the Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI) and the Optical Spectrograph and Infra-Red Imager ... |
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| Polar Mesospheric Cloud Mass and the Ice Budget: 2. Application to Satellite Data Sets |
20 Apr 2007 |
9 pages |
| Authors:
Michael H Stevens; Christoph R Englert; Matthew T DeLand; Scott M Bailey; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
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| We use satellite observations of mid-UV solar backscattered light from polar mesospheric clouds (PMCs) to constrain the water ice budget. We compare the PMC mass from observations by two instruments: the limb viewing Student Nitric Oxide Explorer (SNOE) and the nadir viewing Solar Backscattered UltraViolet (SBUV) experiments. At 70 +or- 2.5N we find that SNOE measures over three times more PMC mass than the less sensitive SBUV experiment. We directly ... |
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| Polar Mesospheric Cloud Mass and the Ice Budget: 1. Quantitative Interpretation of Mid-UV Cloud Brightness Observations |
20 Apr 2007 |
8 pages |
| Authors:
Christoph R Englert; Michael H Stevens; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
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| The researchers investigated the retrieval of column ice mass from mid-UV solar scattering polar mesospheric cloud (PMC) observations to help constrain estimates of the ice budget of the polar summer mesosphere. First, they showed that the backscattered brightness from PMC particles is roughly proportional to the mass of the ice particles. Second, they quantified the sensitivity of the retrieved PMC column ice mass to the particle size distribution for a ... |
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| Polar Mesospheric Cloud Mass and the Ice Budget: 3. Application of a Coupled Ice-Chemistry-Dynamics Model and Comparison with Observations |
Jan 2007 |
10 pages |
| Authors:
David E Siskind; Mark Hervig; Jorg Gumbel; Michael H Stevens; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
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| We have combined a two-dimensional chemical/dynamics model with a monodisperse parameterization of polar mesospheric clouds (PMCs) to study the interaction of PMCs with the climate of the summer mesopause region. First, we show that PMC absorption of terrestrial and solar IR radiation lead to atmospheric heating rates which can exceed 10 degrees Kelvin/day. This heat is dissipated by increased upwelling above the cloud layer and by a 2-6 degree Kelvin ... |
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| Doppler Asymmetric Spatial Heterodyne Spectroscopy (DASH): An Innovative Concept for Measuring Winds in Planetary Atmospheres |
Jan 2006 |
9 pages |
| Authors:
Christoph R Englert; John M Harlander; David D Babcock; Michael H Stevens; David E Siskind; NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
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| We introduce an innovative concept for inferring altitude profiles of horizontal wind in planetary atmospheres by measuring the Doppler shift of multiple emission lines versus altitude. Instruments using this approach will be especially well suited for interplanetary missions because they will be compact, rugged, and lightweight while minimizing power consumption and maximizing sensitivity, all without moving parts. |
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| Antarctic Mesospheric Clouds Formed From Space Shuttle Exhaust |
06 Jul 2005 |
7 pages |
| Authors:
Michael H Stevens; R R Meier; Xinzhao Chu; Matthew T DeLand; John M Plane; NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
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| New satellite observations reveal lower thermospheric transport of a space shuttle exhaust plume into the southern hemisphere two days after a January, 2003 launch. A day later, ground-based lidar observations in Antarctica identify iron ablated from the shuttle's main engines. Additional satellite observations of polar mesospheric clouds (PMCs) show a burst that constitutes 10-20% of the PMC mass between 65-79 deg S during the 2002-2003 season, comparable to previous results ... |
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| The Polar Mesospheric Cloud Mass in the Arctic Summer |
19 Feb 2005 |
12 pages |
| Authors:
Michael H Stevens; Christoph R Englert; Matthew T DeLand; Mark Hervig; NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
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| We infer the polar mesospheric cloud (PMC) mass throughout the Arctic summer using results from two sets of satellite observations and a microphysical model. Solar backscatter ultraviolet (SBUV) PMC observations in July 1999 indicate a burst of activity persisting for 8 days after a space shuttle launch and averaging 262 plus or minus 52 t near 4.7 local time. This mass is consistent with the propellant mass available from the ... |
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| Shimmer on STS-112: Development and Proof-of-Concept Flight |
Sep 2003 |
11 pages |
| Authors:
Joel G Cardon; Christoph R Englert; John M Harlander; Fred L Roesler; Michael H Stevens; NAVAL RESEARCH LAB WASHINGTON DC
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| The Spatial Heterodyne Imager for Mesospheric Radicals (SHIMMER), which is based on a new interferometric technique called Spatial Heterodyne Spectroscopy (SHS), flew on the Space Shuttle Atlantis mission STS-112 in October 2002. SHS has the advantages of high throughput, high spectral resolution, small size, low mass, all in a rugged instrument with no moving optical components. The SHS proof-of-principal flight successfully demonstrated the suitability of SHS for spaceflight applications where ... |
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| Polar Mesospheric Clouds Formed From Space Shuttle Exhaust |
31 May 2003 |
5 pages |
| Authors:
Michael H Stevens; Jorg Gumbel; Christoph R Englert; Klaus U Grossmann; Markus Rapp; Paul Hartogh; NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
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| We observe a plume of water vapor in the Arctic above 85 km and a day after an August shuttle launch. Our satellite observations reveal that a discrete region of polar mesospheric clouds (PMCs) appears a week after that launch. We calculate that the water contained in the observed PMCs is consistent with the amount injected by the shuttle. This is evidence for a source of PMCs not previously considered. ... |
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| OH Observations of Space Shuttle Exhaust |
21 May 2002 |
5 pages |
| Authors:
Michael H Stevens; Christoph R Englert; NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
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| We report the unexpected observation of a large hydroxyl (OH) cloud north and east of the United States a day after a space shuttle launch in November 1994. The Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI) observed OH(0,0) solar fluorescence near 309 nm while staring toward a tangent altitude of 87 km, where OH can be produced from water vapor photodissociation. The OH(0,0) band has a rotational temperature of 252 ... |
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| The Extreme Ultraviolet Airglow of N2 Atmospheres |
Jan 2002 |
9 pages |
| Authors:
Michael H Stevens; NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
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| Extreme ultraviolet (EUV) airglow observations at Titan, Triton and Earth provide a rigorous test for models of N2 atmospheres. This is primarily because the emissions are produced in dramatically different environments. EUV spectra obtained by the Voyager Ultraviolet Spectrometer (UVS) at Titan and Triton are dominated by emission arising from electron impact on N2 and by photodissociative ionization of N2. Spectral analyses of the UVS data originally showed that the ... |
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| PMCs and the Water Frost Point in the Arctic Summer Mesosphere |
01 Dec 2001 |
5 pages |
| Authors:
Michael H Stevens; Robert R Conway; Christoph R Englert; Michael B Summers; Klaus U Grossmann; Oleg A Gusev; NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
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| In August, 1997 the Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI) obtained vertical profiles of OH number density and polar mesospheric cloud (PMC) brightness by scanning the limb up to 71 deg N while the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) obtained co-located vertical profiles of temperature. MAHRSI OH densities are converted to water vapor using a one-dimensional model that assumes photochemical equilibrium. By combining water vapor ... |
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| The EUV Airglow of Titan: Production and Loss of N2 c'4(0) - X |
01 Mar 2001 |
7 pages |
| Authors:
Michael H Stevens; NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
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| The N(2) Carroll-Yoshino (CY) c'(4) X (0,0) and (0,1) Rydberg bands between 95 and 99 nm were reported to be the most prominent EUV emission features in Voyager 1 ultraviolet spectrometer (UVS) airglow spectra from Titan's atmosphere. Although c'(4) is strongly excited by photoelectron impact, the (0,0) band is optically thick near peak production, so a multiple-scattering model is employed to calculate (0,v) nadir-viewing intensities. The model accounts for all ... |
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| THOMAS 2.5 THz Measurements of Middle Atmospheric OH: Comparison With MAHRSI Observations and Model Results |
Jan 2000 |
7 pages |
| Authors:
Christoph R Englert; Birger A Schimpf; Manfred Birk; Franz Schreier; Robert R Conway; Michael H Stevens; Michael E Summers; NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
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| In this work OH observations of the middle atmosphere performed by the improved 2.5 THz heterodyne spectrometer THOMAS (Tera Hertz OH Measurement Airborne Sounder) during the 1997 THOMAS/MAHRSI (Middle Atmosphere High Resolution Spectrograph investigation) campaign are presented. Results of the THOMAS OH measurements are compared to simultaneous MAHRSI OH observations and to photochemical model calculations using both standard HO(sub x) chemistry and a recently proposed change in HO(sub x) chemistry. ... |
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