Global observations of middle atmospheric water vapour by the Odin satellite: An overview

Urban, Joachim; Lautie, Nicolas; Murtagh, Donal; Eriksson, Patrick; Kasai, Yasuko; Lossow, Stefan; Dupuy, É.; Noë, J. de La; Frisk, U.; Olberg, M.; Flochmoën, É. Le; Ricaud, Philippe

doi:10.1016/j.pss.2006.11.021

Cited by 65 publications

(56 citation statements)

References 40 publications

(34 reference statements)

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“…Our model of NO is based on measurements by the SubMillimeter Radiometer (SMR) instrument on the Odin satellite (Murtagh et al, 2002). Trace-gas measurements, including NO, have been made by Odin-SMR since October 2003 (for a description of the measurement technique see Urban et al, 2007). Until May 2007, the relevant height range was covered for only about 1 day per month, but since then the coverage has increased to about 4 days per month.…”

Section: Ion and No Production Rate Modelmentioning

confidence: 99%

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

et al. 2015

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Abstract. 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-ofmagnitude 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 arrival of the HSS. These are of the same order of magnitude but generally larger than would be expected from direct production by HSS-associated EEP, indicating that downward transport likely contributes in addition to direct production.

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Section: Ion and No Production Rate Modelmentioning

confidence: 99%

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

et al. 2015

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“…Odin/SMR measures several atmospheric emission lines of water vapour and its isotopes (Urban et al, 2007 This time in combination with the spectrometer read-out times and the antenna characteristics determines the effective altitude resolution of the measurements, which is in the order of around 3 km. The horizontal resolution in this altitude layer is characterised by the path length, which is about 400 km.…”

Section: Measurements Of the 557 Ghz Band And Its Retrievalmentioning

confidence: 99%

“…Above 90 km the statistical error can easily exceed 50%. For more detailed information about the Odin/SMR mesospheric water vapour retrieval the reader is referred to Urban et al (2007) and .…”

Section: Measurements Of the 557 Ghz Band And Its Retrievalmentioning

confidence: 99%

Observations of the mesospheric semi-annual oscillation (MSAO) in water vapour by Odin/SMR

et al. 2008

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Abstract. Mesospheric water vapour measurements taken by the SMR instrument aboard the Odin satellite between 2002 and 2006 have been analysed with focus on the mesospheric semi-annual circulation in the tropical and subtropical region. This analysis provides the first complete picture of mesospheric SAO in water vapour, covering altitudes above 80 km where previous studies were limited. Our analysis shows a clear semi-annual variation in the water vapour distribution in the entire altitude range between 65 km and 100 km in the equatorial area. Maxima occur near the equinoxes below 75 km and around the solstices above 80 km. The phase reversal occurs in the small layer inbetween, consistent with the downward propagation of the mesospheric SAO in the zonal wind in this altitude range. The SAO amplitude exhibits a double peak structure in the equatorial region, with maxima at about 75 km and 81 km. The observed amplitudes show higher values than an earlier analysis based on UARS/HALOE data. The upper peak amplitude remains relatively constant with latitude. The lower peak amplitude decreases towards higher latitudes, but recovers in the Southern Hemisphere subtropics. On the other hand, the annual variation is much more prominent in the Northern Hemisphere subtropics. Furthermore, higher volume mixing ratios during summer and lower values during winter are observed in the Northern Hemisphere subtropics, as compared to the corresponding latitude range in the Southern Hemisphere.

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“…Trace-gas measurements, including NO, covering the summer mesopause region, have been made by Odin-SMR since October 2003 (for a description of the measurement technique see Urban et al, 2007). Until May 2007, the relevant height range was covered for only about one day per month, but since then the coverage has increased to about 4 days per month.…”

Section: Discussionmentioning

confidence: 99%

Response of polar mesosphere summer echoes to geomagnetic disturbances in the Southern and Northern Hemispheres: the importance of nitric oxide

et al. 2013

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The relationship between polar mesosphere summer echoes (PMSE) and geomagnetic disturbances (represented by magnetic <I>K</I> indices) is examined. Calibrated PMSE reflectivities for the period May 2006–February 2012 are used from two 52.0/54.5 MHz radars located in Arctic Sweden (68° N, geomagnetic latitude 65°) and at two different sites in Queen Maud Land, Antarctica (73°/72° S, geomagnetic latitudes 62°/63°). In both the Northern Hemisphere (NH) and the Southern Hemisphere (SH) there is a strong increase in mean PMSE reflectivity between quiet and disturbed geomagnetic conditions. Mean volume reflectivities are slightly lower at the SH locations compared to the NH, but the position of the peak in the lognormal distribution of PMSE reflectivities is close to the same at both NH and SH locations, and varies only slightly with magnetic disturbance level. Differences between the sites, and between geomagnetic disturbance levels, are primarily due to differences in the high-reflectivity tail of the distribution. PMSE occurrence rates are essentially the same at both NH and SH locations during most of the PMSE season when a sufficiently low detection threshold is used so that the peak in the lognormal distribution is included. When the local-time dependence of the PMSE response to geomagnetic disturbance level is considered, the response in the NH is found to be immediate at most local times, but delayed by several hours in the afternoon sector and absent in the early evening. At the SH sites, at lower magnetic latitude, there is a delayed response (by several hours) at almost all local times. At the NH (auroral zone) site, the dependence on magnetic disturbance is highest during evening-to-morning hours. At the SH (sub-auroral) sites the response to magnetic disturbance is weaker but persists throughout the day. While the immediate response to magnetic activity can be qualitatively explained by changes in electron density resulting from energetic particle precipitation, the delayed response can largely be explained by changes in nitric oxide concentrations. Observations of nitric oxide concentration at PMSE heights by the Odin satellite support this hypothesis. Sensitivity to geomagnetic disturbances, including nitric oxide produced during these disturbances, can explain previously reported differences between sites in the auroral zone and those at higher or lower magnetic latitudes. The several-day lifetime of nitric oxide can also explain earlier reported discrepancies between high correlations for average conditions (year-by-year PMSE reflectivities and <I>K</I> indices) and low correlations for minute-to-day timescales

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Global observations of middle atmospheric water vapour by the Odin satellite: An overview

Cited by 65 publications

References 40 publications

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

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

Observations of the mesospheric semi-annual oscillation (MSAO) in water vapour by Odin/SMR

Response of polar mesosphere summer echoes to geomagnetic disturbances in the Southern and Northern Hemispheres: the importance of nitric oxide

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