| 1. |
- Khosravi, Maryam, 1975, et al.
(författare)
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Climatologies of stratospheric short-lived species from Odin/SMR: Methodology for ClO
- 2013
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Ingår i: Proceedings ESA Living Planet Symposium, 9-13 September 2013, Edinburgh (UK). ESA-SP-722 : European Space Agency, Noordwijk, The Netherlands. - 1609-042X. - 9789292212865 ; , s. 1-6
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Sub-Millimetre Radiometer (SMR) on board theOdin satellite has been measuring short-lived strato-spheric species such as chlorine monoxide (ClO) sinceOdin’s launch in 2001. Odin/SMR at its sun-synchronousorbit measures at certain local times observations aroundsunrise and sunset at the equator. Due to the drift ofOdin’s orbit in local solar time and the fact that mea-surements are done at different local times, a correctionis required before a monthly zonal mean climatologycan be calculated and trends of ClO can be evaluated.To deal with this, scaling factors are calculated using aphoto-chemical box model for correction of the mixingratios respective to a reference time. The uncertaintiesand limitations of this method are estimated by checkingthe internal consistency of the results, so that comparingthe scaled a.m. ClO time-series to p.m. scaled time-series should give the same results. We found out thatscaling SMR ClO to the ascending time of MicrowaveLimb Sounder (MLS) as reference at about 1.30 a.m. atthe equator gives better result compared to the scalingClO to MLS descending node at about 1.30. p.m. Thetime series calculated for the morning SMR ClO scaled(to 1.30 a.m.) agrees with the evening ClO scaled.
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| 2. |
- Perot, Kristell, 1985, et al.
(författare)
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Odin/SMR Observations of a Particularly Strong Midwinter Stratospheric Sudden Warming in Early 2013
- 2013
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Ingår i: Proceedings of ESA Living Planet Symposium. - 1609-042X. - 9789292212865 ; SP-722
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Sub-Millimetre Radiometer (SMR), on boardthe Odin satellite, observed a major stratospheric suddenwarming (SSW) in the northern hemisphere in earlyJanuary 2013. The provided measurements have beenused to identify and characterize this event which seemsto be the strongest of that kind in recent years. Thispaper is based on a comparison with the 2009 SSWwhich was so far considered as a record-breaking event.SSWs are an important manifestation of the couplingphenomena between the mesosphere / lowerthermosphere and the lower atmospheric layers and canstrongly affect the middle atmospheric composition. It iscrucial to study these events in order to get a betterunderstanding of the dynamical and chemicalmechanisms that control this part of the atmosphere.
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| 3. |
- Sagi, Kazutoshi, 1984, et al.
(författare)
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Twelve years of Arctic ozone loss observed by the Odin satellite
- 2013
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Ingår i: Proceedings of ESA Living Planet Symposium, SP-722. - 1609-042X. - 9789292212865
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In 2011, several groups reported dramatic ozone depletion over the arctic polar region approaching that of the Antarctic ozone hole. Odin, The Swedish-led satellite project in collaboration with Canada, France and Finland, was launched in February 2001 and continues to produce profiles of chemical species relevant to understanding the middle and upper atmosphere.This study concerns ozone loss over the northern pole utilizing the 12 years of ozone data from Odin/SMR.The unstable nature of the arctic vortex due to the propagation of planetary waves from troposphere makes quantifying chemical ozone loss in the arctic more difficult. The assimilation technique using a transport model is useful for separating the dynamical and chemical changes in the ozone amount as demonstrated earlier by Roseval et al (2007) . We have applied this method with a number of improvements to study the inter-annual variability during the entire Odin period.
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| 4. |
- Urban, Joachim, 1964, et al.
(författare)
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Global observations of stratospheric heavy ozone isotopologue enrichment with the Odin Sub-Millimetre Radiometer
- 2013
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Ingår i: Proceedings ESA Living Planet Symposium, 9-13 September 2013, Edinburgh (UK). - 1609-042X. - 9789292212865 ; ESA-SP-722
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Odin Sub-Millimetre Radiometer (SMR) measures thermal emission lines of several minor ozone isotopologues such as symmetric and asymmetric O3-18 and asymmetric O3-17 at the atmospheric limb. The global data set spans over 11 years starting in late 2001. The basic characteristics and limitations of the observational data are presented and the global distribution of heavy ozone isotopologue enrichment as seen by Odin is described and discussed. Best results in terms of spatial coverage are obtained for asymmetric O3-18, which shows a characteristic increase of the enrichment in the middle to upper stratosphere and the smallest enrichment in the polar lower stratosphere. Symmetric O3-18 is characterised by a layer of maximum enrichment in the middle stratosphere.
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| 7. |
- Berg, Anders, 1983, et al.
(författare)
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Demonstration of X-Band SAR Interferometry over Baltic Fast Ice
- 2013
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Ingår i: Proceedings of Earth Observation and Cryosphere Science, 13 - 16 November 2012, Frascati, Italy. - 1609-042X. - 9789290922766 ; 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study utilizes X-band SAR images acquired by theCosmo-SkyMed satellite constellation to map fast icedeformation at high spatial resolution. Twointerferometric acquisitions were performed in themiddle of the ice season in 2012 and with a temporalbaseline of 24 hours. The first interferogram revealsdeformation of the fast ice which is being forced by theramming drift ice. The drift ice moved towards the fastice with up to 600 m based on phase correlationmeasurements. The second interferogram shows a ratherlow fringe rate over the fast ice with fringes beingaligned along the coastline. Emerging cracks are easilyidentified with the associated phase discontinuities. It isalso observed that the backscatter and coherence levelsare connected in certain regions.
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| 8. |
- Berg, Anders, 1983, et al.
(författare)
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Evaluation of a sea ice algorithm for SAR data from the Bay of Bothnia
- 2010
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Ingår i: Proceedings of the Third International Workshop SeaSAR 2010, 25-29 January 2010, Frascati, Italy. - 1609-042X. - 9789292212438 ; ESA SP-679
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A sea ice drift algorithm published by M. Thomas et. al.(2008) has been implemented and evaluated. Input tothe algorithm is Synthetic Aperture Radar (SAR)images, which are processed using phase correlation ina multi-resolution processing system. The algorithm hasbeen tested with horizontally co-polarized (HH)ENVISAT ASAR Wide Swath images andRADARSAT-2 ScanSAR images. The possible benefitsof using cross-polarized (HV) RADARSAT-2 ScanSARdata are investigated, and initial testing of the algorithmfor L-band SAR data from ALOS PALSAR has beendone.The validity of the produced motion fields has beentested in three different ways. Most of the SAR imagesin this analysis were acquired over the Bay of Bothnia.Five meteorological stations located in this region havebeen collecting wind data with a temporal resolution ofthree hours. It is confirmed that the wind data correlateswith the derived sea ice motion. Another source ofvalidation data that has been used is the daily ice chartspublished by the Swedish Meteorological andHydrological Institute (SMHI). The third method usedfor validation is straightforward, visual tracking of seaice features.The algorithm is facing some difficulties when it comesto ice tracking close to the shoreline, in archipelagoesetc, since the motionless solution will be favoured. Itcan however be suppressed by filtering areas of land.This addition gives a more robust algorithm.
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| 9. |
- Dischler, Johann, et al.
(författare)
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Predicted properties of eclipsing binaries observable by Gaia
- 2005
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Ingår i: European Space Agency, (Special Publication) ESA SP. - 1609-042X .- 0379-6566. ; 576, s. 569-572
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Konferensbidrag (refereegranskat)abstract
- Using a population synthesis model we estimate the fraction of stars of different types that are likely to show eclipses, as a function of the period. The population model is based on the bse-code from Hurley et al. (2002) which is a rapid binary evolution code that include all common effects in close binaries such as mass transfer, tidal locking, wind etc. We use this to evolve millions of systems from original distributions in separation, mass and eccentricity, with ages between zero and 12 Gyr, to get a population of systems representative of our Galaxy. The binary data from our model are then analysed in order to, statistically, see how many eclipsing systems we should have. This is done with a simple model where we neglect limb-darkening and other complicating effects. Assuming a random distribution of the inclination angle the probability of an eclipse of a given depth, Am, can easily be calculated. Adding a reasonable fraction of true single stars, we can finally estimate the fraction of eclipsing binaries in limited areas of the HR-diagram, as a function of the period. A first comparison with observational data from the Hipparcos mission shows quite satisfying agreement, and extrapolation to Gaia should thus be a natural application. We find that Gaia will observe about 500 000 eclipsing binaries, this (surprisingly) small number arises from the fact that many eclipsing systems will not be detected by Gaia.
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| 10. |
- Dorch, S.B.F., et al.
(författare)
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Dynamo action in M-dwarfs
- 2005
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Ingår i: ESA SP (Special Publication). - 1609-042X .- 0379-6566. ; 560, s. 515-517
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Konferensbidrag (refereegranskat)
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