Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rocket-borne in situ measurements in the middle atmosphere
Stockholm University, Faculty of Science, Department of Meteorology.
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The Earth's mesosphere and lower thermosphere in the altitude range 50-130 km is a fascinating part of our atmosphere. Complex interactions between radiative, dynamical, microphysical and chemical processes give rise to several prominent phenomena, many of those centred around the mesopause region (80-100 km). These phenomena include noctilucent clouds, polar mesosphere summer echoes, the ablation and transformation of meteoric material, and the Earth’s airglow. Strong stratification and small scale interactions are common features of both these phenomena and the mesopause region in general. In order to study interactions on the relevant spatial scales, in situ measurements from sounding rockets are essential for mesospheric research.

This thesis presents new measurement techniques and analysis methods for sounding rockets, thus helping to improve our understanding of this remote part of the atmosphere. Considering the need to perform measurements at typical rocket speeds of 1 km/s, particular challenges arise both from the design of selective, sensitive, well-calibrated instruments and from perturbations due to aerodynamic influences. This thesis includes a quantitative aerodynamic analysis of impact and sampling techniques for meteoric particles, revealing a distinct size discrimination due to the particle flow. Optical techniques are investigated for mesospheric ice particle populations, resulting in instrument concepts for accessing smaller particles based on Mie scattering at short ultraviolet wavelengths. Rocket-borne resonance fluorescence measurements of atomic oxygen are critically re-assessed, leading to new calibration concepts based on photometry of O2 airglow emissions.

The work presented here also provides important pre-studies for the upcoming PHOCUS rocket campaign from Esrange in July 2010. PHOCUS will address the interaction between three major mesospheric players: meteoric smoke, noctilucent clouds and gas-phase chemistry.

Place, publisher, year, edition, pages
Stockholm: Meteorologiska institutionen (MISU) , 2009. , 59 p.
Keyword [en]
rocket measurements, noctilucent clouds, meteoric smoke, nightglow, mesosphere, aerodynamics
National Category
Natural Sciences
Research subject
Atmospheric Sciences
Identifiers
URN: urn:nbn:se:su:diva-8462ISBN: 978-91-7155-813-8 (print)OAI: oai:DiVA.org:su-8462DiVA: diva2:200309
Public defence
2009-02-20, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 12 A, Stockholm, 10:00
Opponent
Supervisors
Available from: 2009-01-29 Created: 2009-01-22Bibliographically approved
List of papers
1. On the efficiency of rocket-borne particle detection in the mesosphere
Open this publication in new window or tab >>On the efficiency of rocket-borne particle detection in the mesosphere
2007 (English)In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 7, no 14, 3701-3711 p.Article in journal (Refereed) Published
Abstract [en]

Meteoric smoke particles have been proposed as a key player in the formation and evolution of mesospheric phenomena. Despite their apparent importance still very little is known about these particles. Important questions concern the smoke number density and size distribution as a function of altitude as well as the fraction of charged particles. Sounding rockets are used to measure smoke in situ, but aerodynamics has remained a major challenge. Basically, the small smoke particles tend to follow the gas flow around the payload rather than reaching the detector if aerodynamics is not considered carefully in the detector design. So far only indirect evidence for the existence of meteoric smoke has been available from measurements of heavy charge carriers. Quantitative ways are needed that relate these measured particle population to the atmospheric particle population. This requires in particular knowledge about the size-dependent, altitude-dependent and charge-dependent detection efficiency for a given instrument. In this paper, we investigate the aerodynamics for a typical electrostatic detector design. We first quantify the flow field of the background gas, then introduce particles in the flow field and determine their trajectories around the payload structure. We use two different models to trace particles in the flow field, a Continuous motion model and a Brownian motion model. Brownian motion is shown to be of basic importance for the smallest particles. Detection efficiencies are determined for three detector designs, including two with ventilation holes to allow airflow through the detector. Results from this investigation show that rocket-borne smoke detection with conventional detectors is largely limited to altitudes above 75 km. The flow through a ventilated detector has to be relatively large in order to significantly improve the detection efficiency.

National Category
Meteorology and Atmospheric Sciences
Research subject
Atmospheric Sciences
Identifiers
urn:nbn:se:su:diva-25697 (URN)000248733100002 ()
Note
Part of urn:nbn:se:su:diva-8462Available from: 2009-01-29 Created: 2009-01-22 Last updated: 2017-12-13Bibliographically approved
2. The aerodynamics of the MAGIC meteoric smoke sampler
Open this publication in new window or tab >>The aerodynamics of the MAGIC meteoric smoke sampler
2007 (English)In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 40, no 6, 818-824 p.Article in journal (Refereed) Published
Abstract [en]

The detection of nanometre-sized meteoric smoke particles in the Earth’s mesosphere and lower thermosphere is difficult. The particles are too small for optical detection and so far only the charged fraction of the particles has been probed by rocket-borne instruments. One way to obtain maximum information about the smoke particles is direct sampling with rocket-borne particle samplers. The MAGIC project (Mesospheric Aerosol – Genesis, Interaction and Composition) aims to quantitatively answer fundamental questions about the properties of smoke in the atmosphere. The first launch of such particle samplers was performed during the MAGIC rocket campaign from Esrange, Sweden, in January 2005. In order to characterise the sampling process, we have performed simulations of the trajectories of nanometre-sized dust particles towards the MAGIC detectors with a new particle motion model. An important feature of this model is the Brownian motion of the particles due to thermal collisions of the gas molecules. As a result, we obtain the detection efficiency for the MAGIC detectors as a function of altitude and particle size. Our simulations confirm that particles of radii down to 0.75 nm impact on the sampling surface with an efficiency exceeding 80% over the entire mesospheric altitude range of interest.

National Category
Meteorology and Atmospheric Sciences
Research subject
Atmospheric Sciences
Identifiers
urn:nbn:se:su:diva-25698 (URN)10.1016/j.asr.2007.06.046 (DOI)000253589700012 ()
Note
Part of urn:nbn:se:su:diva-8462Available from: 2009-01-29 Created: 2009-01-22 Last updated: 2017-12-13Bibliographically approved
3. Observations of positively charged nanoparticles in the nighttime polar mesosphere
Open this publication in new window or tab >>Observations of positively charged nanoparticles in the nighttime polar mesosphere
Show others...
2005 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 32, L23821- p.Article in journal (Refereed) Published
Abstract [en]

We present results of in situ measurements of charged nanoparticles, electrons, and positive ions obtained during a sounding rocket flight in October 2004 from Kiruna, Sweden, under nighttime conditions. The particle measurement reveals positive charge signatures in the altitude range between 80 and 90 km corresponding to peak charge number densities of ∼100 e/cm3 at around 86 km. Aerodynamical analysis of the sampling efficiency of our instrument reveals that the particles must have been larger than 2 nm assuming spherical particles with a density of 3 g/cm3. The plasma environment of the observed particles is dominated by negative and positive ions, with only few free electrons. A calculation of the mean particle charge expected for particles in a plasma consisting of electrons and positive and negative ions shows that the presence of sufficiently heavy and numerous negative ions (i.e., m n > 300 amu and λ ≥ 50) can explain the observed positive particle charge.

National Category
Meteorology and Atmospheric Sciences
Research subject
Atmospheric Sciences
Identifiers
urn:nbn:se:su:diva-25699 (URN)10.1029/2005GL024676 (DOI)
Note
Part of urn:nbn:se:su:diva-8462Available from: 2009-01-29 Created: 2009-01-22 Last updated: 2017-12-13Bibliographically approved
4. Optical studies of noctilucent clouds in the extreme ultraviolet
Open this publication in new window or tab >>Optical studies of noctilucent clouds in the extreme ultraviolet
Show others...
2008 (English)In: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 26, no 5, 1109-1119 p.Article in journal (Refereed) Published
Abstract [en]

In order to better understand noctilucent clouds (NLC) and their sensitivity to the variable environment of the polar mesosphere, more needs to be learned about the actual cloud particle population. Optical measurements are today the only means of obtaining information about the size of mesospheric ice particles. In order to efficiently access particle sizes, scattering experiments need to be performed in the Mie scattering regime, thus requiring wavelengths of the order of the particle size. Previous studies of NLC have been performed at wavelengths down to 355 nm from the ground and down to about 200 nm from rockets and satellites. However, from these measurements it is not possible to access the smaller particles in the mesospheric ice population. This current lack of knowledge is a major limitation when studying important questions about the nucleation and growth processes governing NLC and related particle phenomena in the mesosphere. We show that NLC measurements in the extreme ultraviolet, in particular using solar Lyman-α radiation at 121.57 nm, are an efficient way to further promote our understanding of NLC particle size distributions. This applies both to global measurements from satellites and to detailed in situ studies from sounding rockets. Here, we present examples from recent rocket-borne studies that demonstrate how ambiguities in the size retrieval at longer wavelengths can be removed by invoking Lyman-α. We discuss basic requirements and instrument concepts for future rocket-borne NLC missions. In order for Lyman-α radiation to reach NLC altitudes, high solar elevation and, hence, daytime conditions are needed. Considering the effects of Lyman-α on NLC in general, we argue that the traditional focus of rocket-borne NLC missions on twilight conditions has limited our ability to study the full complexity of the summer mesopause environment.

National Category
Meteorology and Atmospheric Sciences
Research subject
Atmospheric Sciences
Identifiers
urn:nbn:se:su:diva-25700 (URN)000256224500009 ()
Note
Part of urn:nbn:se:su:diva-8462Available from: 2009-01-29 Created: 2009-01-22 Last updated: 2017-12-13Bibliographically approved
5. Use of O2 airglow for calibrating direct atomic oxygen measurements from sounding rockets
Open this publication in new window or tab >>Use of O2 airglow for calibrating direct atomic oxygen measurements from sounding rockets
2009 (English)In: Atmospheric Measurement Techniques, ISSN 1867-1381, Vol. 2, 801-812 p.Article in journal (Refereed) Published
Abstract [en]

Accurate knowledge about the distribution of atomic oxygen is crucial for many studies of the mesosphere and lower thermosphere. Direct measurements of atomic oxygen by the resonance fluorescence technique at 130 nm have been made from many sounding rocket payloads in the past. This measurement technique yields atomic oxygen profiles with good sensitivity and altitude resolution. However, accuracy is a problem as calibration and aerodynamics make the quantitative analysis challenging. Most often, accuracies better than a factor 2 are not to be expected from direct atomic oxygen measurements. As an example, we present results from the NLTE (Non Local Thermodynamic Equilibrium) sounding rocket campaign at Esrange, Sweden, in 1998, with simultaneous O2 airglow and O resonance fluorescence measurements. O number densities are found to be consistent with the nightglow analysis, but only within the uncertainty limits of the resonance fluorescence technique. Based on these results, we here describe how better atomic oxygen number densities can be obtained by calibrating direct techniques with complementary airglow photometer measurements and detailed aerodynamic analysis. Night-time direct O measurements can be complemented by photometric detection of the O2 (b1g+X3g-) Atmospheric Band at 762 nm, while during daytime the O2 (a1ΔgX3g-) Infrared Atmospheric Band at 1.27 μm can be used. The combination of a photometer and a rather simple resonance fluorescence probe can provide atomic oxygen profiles with both good accuracy and good height resolution.

Keyword
Oxygen, Airglow, in situ measurements, Sounding rockets
National Category
Meteorology and Atmospheric Sciences
Research subject
Atmospheric Sciences
Identifiers
urn:nbn:se:su:diva-25701 (URN)000278086100035 ()
Note
Part of urn:nbn:se:su:diva-8462Available from: 2009-01-29 Created: 2009-01-22 Last updated: 2010-01-21Bibliographically approved

Open Access in DiVA

fulltext(2644 kB)930 downloads
File information
File name FULLTEXT01.pdfFile size 2644 kBChecksum SHA-1
3fd9bf242d6901906ad0341be8eaa0789555f81e195c69351f89a1a8177faf3f617d180c
Type fulltextMimetype application/pdf

By organisation
Department of Meteorology
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 930 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 441 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf