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Sample records for arctic polar vortex

  1. Synoptic scale study of the Arctic polar vortex's influence on the middle atmosphere, 1, Observations

    E-print Network

    Duck, Thomas J.

    Synoptic scale study of the Arctic polar vortex's influence on the middle atmosphere, 1-latitude middle atmosphere taken at three Arctic sites over similar time periods in midwinter. The four reported of the vortex is observed, it is noted that regional middle atmospheric Arctic temperatures can change by tens

  2. A Cold Jovian Arctic Polar Vortex: Evidence from Infrared Imaging

    NASA Astrophysics Data System (ADS)

    Orton, G. S.; Fisher, B. M.; Baines, K. H.; Momary, T.; Fox, O.

    2002-12-01

    A prominent cold arctic airmass in Jupiter is revealed by thermal images taken at NASA's Infrared Telescope Facility (IRTF) during Jupiter's northern summer in 1999. This cold airmass is well defined by a sharp 4-degree thermal gradient in both the stratosphere and the upper troposphere and tropopause regions. The latitude boundary of the cold airmass oscillates in longitude with principal wavenumber 5--6. This longitudinal oscillation is coincident with the oscillation of the boundary of the thick polar hood that is detectable in reflected sunlight that is sensitive to particles around Jupiter's tropopause (~100 mbar pressure), using IRTF 2.3-?m and HST WFPC2 890-nm images. The sinusoidal boundaries slowly rotate prograde with respect to the interior. The proximity and similarity of the thermal and particle boundaries suggests that the phenomenon is a classical polar vortex of the same type as seen in the Earth's antarctic. Testing of possible gaseous entrainment within the vortex' area would verify or refute similarities with polar vortices in the Earth, Venus, Mars and possibly Titan. This phenomenon is relevant to studies of terrestrial meteorology by measuring the extent to which stratospheric phenomena can drive tropospheric properties. Detailed studies of Jupiter's polar regions might be most easily accomplished from appropriate remote sensing instrumentation on a polar orbiter mission as a result of optimized spatial resolution. The work reported here was supported by funds from NASA to the Jet Propulsion Laboratory, California Institute of Technology. Ori Fox was supported by the Undergraduate Student Researcher Program (USRP).

  3. Arctic Vortex

    Atmospheric Science Data Center

    2013-06-26

    article title:  A Vortex Street in the Arctic     ... turbulence patterns occur. von Karman was a professor of aeronautics at the California Institute of Technology and one of the principal ... Science Data Center in Hampton, VA. Image credit: NASA/GSFC/LaRC/JPL, MISR Team. Other formats available at JPL ...

  4. MLS CLO observations and arctic polar vortex temperatures

    NASA Technical Reports Server (NTRS)

    Schoeberl, M. R.; Stolarski, R. S.; Douglass, A. R.; Newman, P. A.; Lait, L. R.; Waters, J. W.; Froidevaux, L.; Ready, W. G.

    1993-01-01

    Analysis of Upper Altmosphere Research Satellite (UARS) Microwave Limb Sounder (MLS) observations in early January 1992 shows a clear relationship between predicted polar stratospheric cloud formation along the back trajectory and elevated ClO amounts. These findings are in good agreement with aircraft observations. The MLS observed variation of ClO amounts within the vortex also fits the pattern of ClO change as a result of air parcel solar exposure and nitric acid photolysis. Outside the polar vortex, the occasional highly elevated ClO appear statistically consistent with MLS measurement noise.

  5. MLS ClO observations and arctic polar vortex temperatures

    SciTech Connect

    Schoeberl, M.R.; Stolarski, R.S.; Douglass, A.R.; Newman, P.A.; Lait, L. R. ); Waters, J.W.; Froidevaux, L.; Ready, W.G. )

    1993-12-23

    Analysis of UARS microwave limb sounder (MLS) observations in early January 1992 shows a clear relationship between predicted polar stratospheric cloud formation along the back trajectory and elevated ClO amounts. These findings are in good agreement with aircraft observations. The MLS observed variation of ClO amounts within the vortex also fits the pattern of ClO change as a result of air parcel solar exposure and nitric acid photolysis. Outside the polar vortex, the occasional highly elevated ClO appear statistically consistent with MLS measurement noise. 14 refs., 5 figs.

  6. Weakening of the Stratospheric Polar Vortex by Arctic Sea-Ice Loss

    SciTech Connect

    Kim, Baek-Min; Son, Seok-Woo; Min, Seung-Ki; Jeong, Jee-Hoon; Kim, Seong-Joong; Zhang, Xiangdong; Shim, Taehyoun; Yoon, Jin-Ho

    2014-09-02

    Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea ice, the mechanism that links sea ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea ice cover during early winter months (November-December), especially over the Barents-Kara seas, enhance the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January- February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes.

  7. Ozone loss in the Arctic polar vortex inferred from high-altitude aircraft measurements

    NASA Technical Reports Server (NTRS)

    Proffitt, M. H.; Margitan, J. J.; Kelly, K. K.; Loewenstein, M.; Podolske, J. R.

    1990-01-01

    The Arctic polar vortex in winter is known to be chemically primed for ozone depletion, yet it does not exhibit the large seasonal ozone decrease that characterizes its southern counterpart. This difference may be due in part to a net flux of ozone-rich air through the Arctic vortex, which can mask ozone loss. But by using a chemically conserved tracer as a reference, significant ozone loss can be identified. This loss is found to be correlated with high levels of chlorine monoxide, suggesting that much of the decrease in ozone is caused by anthropogenic emissions of chlorofluorocarbons.

  8. Stratospheric meteorological conditions in the Arctic polar vortex, 1991 to 1992

    NASA Technical Reports Server (NTRS)

    Newman, P.; Lait, L. R.; Schoeberl, M.; Nash, E. R.; Kelly, K.; Fahey, D. W.; Nagatani, R.; Toohey, D.; Avallone, L.; Anderson, J.

    1993-01-01

    Stratospheric meteorological conditions during the Airborne Arctic Stratospheric Expedition II (AASE II) presented excellent observational opportunities from Bangor, Maine, because the polar vortex was located over southeastern Canada for significant periods during the 1991-1992 winter. Temperature analyses showed that nitric acid trihydrates (NAT temperatures below 195 K) should have formed over small regions in early December. The temperatures in the polar vortex warmed beyond NAT temperatures by late January (earlier than normal). Perturbed chemistry was found to be associated with these cold temperatures.

  9. Stratospheric meterological conditions in the Arctic polar vortex, 1991 to 1992

    SciTech Connect

    Newman, P.; Lait, L.R.; Schoeberl, M. ); Nash, E.R. ); Kelly, K.; Fahey, D.W. ); Nagatani, R. ); Toohey, D.; Avallone, L. ); Anderson, J. )

    1993-08-27

    Stratospheric meterological conditions during the Airborne Arctic Stratospheric Expedition II (AASE II) presented excellent observational opportunities from Bangor, Maine, because the polar vortex was located over southeastern Canada for significant periods during the 1991-1992 winter. Temperature analyses showed that nitric acid trihydrates (NAT temperatures below 195 k) should have formed over small regions in early December. The temperatures in the polar vortex warmed beyond NAT temperatures by late January (earlier than normal). Perturbed chemistry was found to be associated with these cold temperatures.

  10. Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter

    NASA Technical Reports Server (NTRS)

    Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoeberl, M. R.; Elkins, J. W.; Wamsley, P. R.; Dutton, G. S.; Bui, T. P.; Kohn, D. W.; Anderson, J. G.

    1998-01-01

    Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (theta about 450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NO(sub y)) had also been removed, with layers of enhanced (sub y) at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (about 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 micron) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range of theta is estimated to have been dehydrated in this event.

  11. Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter

    NASA Technical Reports Server (NTRS)

    Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoeberl, M. R.; Elkins, J. W.; Wamsley, P. R.; Dutton, G. S.; Bui, T. P.; Kohn, D. W.; Anderson, J. G.

    1998-01-01

    Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (theta approximately 450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NO(y)) had also been removed, with layers of enhanced NO(y) at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (approximately 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 micrometers) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range Transport of theta is estimated to have been dehydrated in this event.

  12. Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter

    NASA Technical Reports Server (NTRS)

    Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoerberl, M. R.; Elkins, J. W.; Wamsley, P. R.

    1998-01-01

    Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (theta = 450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NOy) had also been removed, with layers of enhanced NOy at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (approx. 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 micrometers) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range of theta is estimated to have been dehydrated in this event.

  13. Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter

    NASA Technical Reports Server (NTRS)

    Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoeberl, M. R.; Elkins, J. W.; Wamsley, P. R.; Dutton, G. S.; Bui, T. P.; Kohn, D. W.; Anderson, J. G.

    1998-01-01

    Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (0-450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NO(y)) had also been removed, with layers of enhanced NO(y) at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (approximately 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 microns) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range of 0 is estimated to have been dehydrated in this event.

  14. Aircraft Emissions Deposited in the Stratosphere and Within the Arctic Polar Vortex. Final report

    SciTech Connect

    Baughcum, S.L.

    1996-04-01

    This report describes an analysis of the quantity of emissions (water vapor, NO(x)) projected to be deposited directly within the Arctic polar vortex by projected fleets of Mach 2.4 high speed civil transports (HSCT`s). It also evaluates the amount of emissions from subsonic aircraft which are emitted into the lower stratosphere using aircraft emission inventories developed earlier for May 1990 as representative of the annual average.

  15. Weakening of the stratospheric polar vortex by Arctic sea-ice loss.

    PubMed

    Kim, Baek-Min; Son, Seok-Woo; Min, Seung-Ki; Jeong, Jee-Hoon; Kim, Seong-Joong; Zhang, Xiangdong; Shim, Taehyoun; Yoon, Jin-Ho

    2014-01-01

    Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea-ice, the mechanism that links sea-ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea-ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea-ice cover during early winter months (November-December), especially over the Barents-Kara seas, enhances the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January-February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes. PMID:25181390

  16. Polar processing in a split vortex: early winter Arctic ozone loss in 2012/13

    NASA Astrophysics Data System (ADS)

    Manney, G. L.; Lawrence, Z. D.; Santee, M. L.; Livesey, N. J.; Lambert, A.; Pitts, M. C.

    2015-02-01

    A sudden stratospheric warming (SSW) in early January 2013 caused the polar vortex to split. After the lower stratospheric vortex split on 8 January, the two offspring vortices - one over Canada and the other over Siberia - remained intact, well-confined, and largely at latitudes that received sunlight until they reunited at the end of January. As the SSW began, temperatures abruptly rose above chlorine activation thresholds throughout the lower stratosphere. The vortex was very disturbed prior to the SSW, and was exposed to much more sunlight than usual in December 2012 and January 2013. Aura Microwave Limb Sounder (MLS) nitric acid (HNO3) data and observations from CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) indicate extensive polar stratospheric cloud (PSC) activity, with evidence of PSCs containing solid nitric acid trihydrate particles during much of December 2012. Consistent with the sunlight exposure and PSC activity, MLS observations show that chlorine monoxide (ClO) became enhanced early in December. Despite the cessation of PSC activity with the onset of the SSW, enhanced vortex ClO persisted until mid-February, indicating lingering chlorine activation. The smaller Canadian offspring vortex had lower temperatures, lower HNO3, lower hydrogen chloride (HCl), and higher ClO in late January than the Siberian vortex. Chlorine deactivation began later in the Canadian than in the Siberian vortex. HNO3 remained depressed within the vortices after temperatures rose above the PSC existence threshold, and passive transport calculations indicate vortex-averaged denitrification of about 4 ppbv; the resulting low HNO3 values persisted until the vortex dissipated in mid-February. Consistent with the strong chlorine activation and exposure to sunlight, MLS measurements show rapid ozone loss commencing in mid-December and continuing through January. Lagrangian transport estimates suggest ~ 0.7-0.8 ppmv (parts per million by volume) vortex-averaged chemical ozone loss by late January near 500 K (~ 21 km), with substantial loss occurring from ~ 450 to 550 K. The surface area of PSCs in December 2012 was larger than that in any other December observed by CALIPSO. As a result of denitrification, HNO3 abundances in 2012/13 were among the lowest in the MLS record for the Arctic. ClO enhancement was much greater in December 2012 through mid-January 2013 than that at the corresponding time in any other Arctic winter observed by MLS. Furthermore, reformation of HCl appeared to play a greater role in chlorine deactivation than in more typical Arctic winters. Ozone loss in December 2012 and January 2013 was larger than any previously observed in those months. This pattern of exceptional early winter polar processing and ozone loss resulted from the unique combination of dynamical conditions associated with the early January 2013 SSW, namely unusually low temperatures in December 2012 and offspring vortices that remained well-confined and largely in sunlit regions for about a month after the vortex split.

  17. The anomalous arctic lower stratospheric polar vortex of 1992-1993

    SciTech Connect

    Manney, G.L.; Zurek, R.W.; Gelman, M.E.; Miller, A.J.; Nagatani, R.

    1994-11-01

    Potential vorticity (PV) gradients defining the lower stratospheric vortex during the 1992-1993 winter were anomalously strong and persistent compared to those during the last 16 Arctic winters. For {approximately}3 months PV gradients were closer to typical Antarctic values than to most Arctic values. Air motion diagnostics computed for 3-dimensional air parcel trajectories confirm that the 1992-1993 Arctic lower stratospheric vortex was substantially more isolated than is typical. Such isolation will delay and reduce the export of the higher ozone typical of the winter lower stratospheric vortex to mid-latitudes. This may have contributed to the record-low total ozone amounts observed in northern mid-latitudes in 1993. 13 refs., 4 figs.

  18. Measurements of condensation nuclei in the Airborne Arctic Stratospheric Expedition - Observations of particle production in the polar vortex

    NASA Technical Reports Server (NTRS)

    Wilson, J. C.; Stolzenburg, M. R.; Clark, W. E.; Loewenstein, M.; Ferry, G. V.; Chan, K. R.

    1990-01-01

    The ER-2 Condensation Nucleus Counter (ER-2 CNC) was operated in the Airborne Arctic Stratospheric Expedition (AASE) in January and February 1989. The ER-2 CNC measures the mixing ratio of particles, CN, with diameters from approximately 0.02 to approximately 1 micron. The spatial distribution of CN in the Arctic polar vortex was found to resemble that measured in the Antarctic in the Spring of 1987. The vertical profile of CN in the vortex was lowered by subsidence. At altitudes above the minimum in the CN mixing ratio profile, CN mixing ratios correlated negatively with that of N2O, demonstrating new particle production. CN serve as nuclei in the formation of Polar Stratospheric Clouds (PSCs) and the concentration of CN can affect PSC properties.

  19. Measurements of condensation nuclei in the Airborne Arctic Stratospheric Expedition: Observations of particle production in the polar vortex

    SciTech Connect

    Wilson, J.C.; Stolzenburg, M.R. ); Clark, W.E. ); Loewenstein, M.; Ferry, G.V.; Chan, K.R. )

    1990-03-01

    The ER-2 Condensation Nucleus Counter (ER-2 CNC) was operated in the Airborne Arctic Stratospheric Expedition (AASE) in January and February 1989. The ER-2 CNC measures the mixing ratio of particles, CN, with diameters from approximately 0.02 {mu}m to approximately 1 {mu}m. The spatial distribution of CN in the Arctic polar vortex was found to resemble that measured in the Antarctic in the Spring of 1987. The vertical profile of CN in the vortex was lowered by subsidence. At altitudes above the minimum in the CN mixing ratio profile, CN mixing ratios correlated negatively with that of N{sub 2}O, demonstrating new particle production. CN serve as nuclei in the formation of Polar Stratospheric Clouds (PSC's) and the concentration of CN can affect PSC properties.

  20. On the observation of mesospheric air inside the arctic stratospheric polar vortex in early 2003

    NASA Astrophysics Data System (ADS)

    Engel, A.; Möbius, T.; Haase, H.-P.; Bönisch, H.; Wetter, T.; Schmidt, U.; Levin, I.; Reddmann, T.; Oelhaf, H.; Wetzel, G.; Grunow, K.; Huret, N.; Pirre, M.

    2005-08-01

    During several balloon flights inside the Arctic polar vortex in early 2003, unusual trace gas distributions were observed, which indicate a strong influence of mesospheric air in the stratosphere. The tuneable diode laser (TDL) instrument SPIRALE (Spectroscopie InFrarouge par Absorption de Lasers Embarqués) measured unusually high CO values (up to 600 ppb) on 27 January at about 30 km altitude. The cryosampler BONBON sampled air masses with very high molecular Hydrogen, extremely low SF6 and enhanced CO values on 6 March at about 25 km altitude. Finally, the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) Fourier Transform Infra-Red (FTIR) spectrometer showed NOy values which are significantly higher than NOy* (the NOy derived from a correlation between N2O and NOy under undisturbed conditions), on 21 and 22 March in a layer centred at 22 km altitude. Thus, the mesospheric air seems to have been present in a layer descending from about 30 km in late January to 25 km altitude in early March and about 22 km altitude on 20 March. We present corroborating evidence from a model study using the KASIMA (KArlsruhe Simulation model of the Middle Atmosphere) model that also shows a layer of mesospheric air, which descended into the stratosphere in November and early December 2002, before the minor warming which occurred in late December 2002 lead to a descent of upper stratospheric air, cutting of a layer in which mesospheric air is present. This layer then descended inside the vortex over the course of the winter. The same feature is found in trajectory calculations, based on a large number of trajectories started in the vicinity of the observations on 6 March. Based on the difference between the mean age derived from SF6 (which has an irreversible mesospheric loss) and from CO2 (whose mesospheric loss is much smaller and reversible) we estimate that the fraction of mesospheric air in the layer observed on 6 March, must have been somewhere between 35% and 100%.

  1. Observation of mesospheric air inside the arctic stratospheric polar vortex in early 2003

    NASA Astrophysics Data System (ADS)

    Engel, A.; Möbius, T.; Haase, H.-P.; Bönisch, H.; Wetter, T.; Schmidt, U.; Levin, I.; Reddmann, T.; Oelhaf, H.; Wetzel, G.; Grunow, K.; Huret, N.; Pirre, M.

    2006-02-01

    During several balloon flights inside the Arctic polar vortex in early 2003, unusual trace gas distributions were observed, which indicate a strong influence of mesospheric air in the stratosphere. The tuneable diode laser (TDL) instrument SPIRALE (Spectroscopie Infra-Rouge par Absorption de Lasers Embarqués) measured unusually high CO values (up to 600 ppb) on 27 January at about 30 km altitude. The cryosampler BONBON sampled air masses with very high molecular Hydrogen, extremely low SF6 and enhanced CO values on 6 March at about 25 km altitude. Finally, the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) Fourier Transform Infra-Red (FTIR) spectrometer showed NOy values which are significantly higher than NOy* (the NOy derived from a correlation between N2O and NOy under undisturbed conditions), on 21 and 22 March in a layer centred at 22 km altitude. Thus, the mesospheric air seems to have been present in a layer descending from about 30 km in late January to 25 km altitude in early March and about 22 km altitude on 20 March. We present corroborating evidence from a model study using the KASIMA (KArlsruhe SImulation model of the Middle Atmosphere) model that also shows a layer of mesospheric air, which descended into the stratosphere in November and early December 2002, before the minor warming which occurred in late December 2002 lead to a descent of upper stratospheric air, cutting off a layer in which mesospheric air is present. This layer then descended inside the vortex over the course of the winter. The same feature is found in trajectory calculations, based on a large number of trajectories started in the vicinity of the observations on 6 March. Based on the difference between the mean age derived from SF6 (which has an irreversible mesospheric loss) and from CO2 (whose mesospheric loss is much smaller and reversible) we estimate that the fraction of mesospheric air in the layer observed on 6 March, must have been somewhere between 35% and 100%.

  2. Enhancements of the refractory submicron aerosol fraction in the Arctic polar vortex: feature or exception?

    NASA Astrophysics Data System (ADS)

    Weigel, R.; Volk, C. M.; Kandler, K.; Hösen, E.; Günther, G.; Vogel, B.; Grooß, J.-U.; Khaykin, S.; Belyaev, G. V.; Borrmann, S.

    2014-11-01

    In situ measurements with a four-channel stratospheric condensation particle counter (CPC) were conducted at up to 20 km altitude on board the aircraft M-55 Geophysica from Kiruna, Sweden, in January through March (EUPLEX 2003, RECONCILE 2010) and in December (ESSenCe 2011). During all campaigns air masses from the upper stratosphere and mesosphere were subsiding inside the Arctic winter vortex, thus initializing a transport of refractory aerosol into the lower stratosphere (? < 500 K). The strength and extent of this downward transport varied between the years depending on the dynamical evolution of the vortex. Inside the vortex and at potential temperatures ? ? 450 K around 11 submicron particles per cm3 were generally detected. Up to 8 of these 11 particles per cm3 were found to contain thermo-stable (at 250 °C) residuals with diameters of 10 nm to about 1 ?m. Particle mixing ratios (150 mg-1) and fractions of non-volatile particles (75% of totally detected particles) exhibited highest values in air masses having the lowest content of nitrous oxide (70 nmol mol-1 of N2O). This indicates that refractory aerosol originates from the upper stratosphere or the mesosphere. Derived from the mixing ratio of the simultaneously measured long-lived tracer N2O, an empirical index serves to differentiate probed air masses according to their origin: inside the vortex, the vortex edge region, or outside the vortex. Previously observed high fractions of refractory submicron aerosol in the 2003 Arctic vortex were ascribed to unusually strong subsidence during that winter. However, measurements under perturbed vortex conditions in 2010 and during early winter in December 2011 revealed similarly high values. Thus, the abundance of refractory aerosol in the lower stratosphere within the Arctic vortices appears to be a regular feature rather than the exception. During December, the import from aloft into the lower stratosphere appears to be developing; thereafter the abundance of refractory aerosol inside the vortex reaches its highest levels in March. The correlations of refractory aerosol with N2O suggest that, apart from mean subsidence, diabatic dispersion inside the vortex significantly contributes to the transport of particles to the Arctic lower stratosphere. A measurement-based estimate of the total mass of refractory aerosol inside the vortex is provided for each campaign. Based on the derived increase of particle mass in the lower stratospheric vortex (100-67 hPa pressure altitude) by a factor of 4.5 between early and late winter, we estimate the total mass of mesospheric particles deposited over the winter 2009/2010 in the entire Arctic vortex to range between 77 × 103 and 375 × 106 kg. This estimate is compared with the expected atmospheric influx of meteoritic material (110 ± 55 × 103 kg per day). Such estimates at present still hold considerable uncertainties, which are discussed in this article. Nevertheless, the results enable placing constraints on the shape of the so far unknown size distribution of refractory aerosol within the vortex.

  3. Arctic sea ice melt, the Polar vortex, and mid-latitude weather: Are they connected?

    NASA Astrophysics Data System (ADS)

    Vihma, Timo; Overland, James; Francis, Jennifer; Hall, Richard; Hanna, Edward; Kim, Seong-Joong

    2015-04-01

    The potential of recent Arctic changes to influence broader hemispheric weather is a difficult and controversial topic with considerable skepticism, as time series of potential linkages are short (<10 years) and the signal-to-noise ratio relative to chaotic weather events is small. A way forward is through further understanding of potential atmospheric dynamic mechanisms. Although not definitive of change in a statistical or in a causality sense, the exceptionally warm Arctic winters since 2007 do contain increased variability according to some climate indices, with six negative (and two positive) Arctic Oscillation atmospheric circulation index events that created meridional flow reaching unusually far north and south. High pressure anomalies developed east of the Ural Mountains in Russia in response to sea-ice loss in the Barents/Kara Seas, which initiated eastward-propagating wave trains of high and low pressure that advected cold air over central and eastern Asia. Increased Greenland blocking and greater geopotential thickness related to low-level temperatures increases led to northerly meridional flow into eastern North America, inducing persistent cold periods. Arctic connections in Europe and western North America are less clear. The quantitative impact of potential Arctic change on mid-latitude weather will not be resolved within the foreseeable future, yet new approaches to high-latitude atmospheric dynamics can contribute to improved extended range forecasts as outlined by the WMO/Polar Prediction Program and other international activities.

  4. Does the HoltonTan Mechanism Explain How the Quasi-Biennial Oscillation Modulates the Arctic Polar Vortex?

    E-print Network

    Garfinkel, Chaim I.

    ) modulates the Northern Hemisphere wintertime stratospheric polar vortex. Overall, the effect of the critical in the tropospheric circulation appear to be less important than lower stratospheric easterlies for the polar stratospheric polar vortex, in agreement with previous studies, although not because of changes

  5. Chemical loss of ozone in the Arctic polar vortex in the winter of 1991-1992

    SciTech Connect

    Salawitch, R.J.; Wofsy, Gottlieb, E.W.; Anderson, J.G. ); Lait, L.R.; Newman, P.A.; Schoeberl, M.R.; Strahan, S.E. ); Loewenstein, M.; Podolske, J.R.; Chan, K.R. ); Proffitt, M.H.; Fahey, D.W.; Kelly, K.K. ); Webster, C.R.; May, R.D. ); Baumgardner, D.; Dye, J.E. ); Wilson, J.C. ); Elkins, J.W. )

    1993-08-27

    In situ measurements of chlorine monoxide, bromine monoxide, and ozone are extrapolated globally, with the use of meterological tracer, to infer the loss rates for ozone in the Arctic lower stratosphere during the Airborne Arctic Stratospheric Expedition II (AASE II) in the winter of 1991-1992. The analysis indicates removal of 15 to 20 percent of ambient ozone because of elevated concentrations of chlorine monoxide and bromine monoxide. Observations during AASE II define rates of removal of chlorine monoxide attributable to reaction with nitrogen dioxide (produced by photolysis of nitric acid) and to production of hydrochloric acid. Ozone loss ceased in March as concentrations of chlorine monoxide declined. Ozone losses could approach 50 percent if regeneration of nitrogen dioxide were inhibited by irreversible removal of nitrogen oxides (denitrification), as presently observed in the Antarctic, or without denitrification if inorganic chlorine concentrations were to double.

  6. Chemical Loss of Ozone in the Arctic Polar Vortex in the Winter of 1991-1992

    NASA Technical Reports Server (NTRS)

    Salawitch, R. J.; Wofsy, S. C.; Gottlieb, E. W.; Lait, L. R.; Newman, P. A.; Schoeberl, M. R.; Strahan, S. E.; Loewenstein, M.; Podolske, J. R.; Chan, K. R.; Proffitt, M. H.; Fahey, D. W.; Kelly, K. K.; Webster, C. R.; May, R. D.; Baumgardner, D.; Dye, J. E.; Wilson, J. C.; Elkins, J. W.; Anderson, J. G.

    1993-01-01

    In situ measurements of chlorine monoxide, bromine monoxide, and ozone are extrapolated globally, with the use of meteorological tracers, to infer the loss rates for ozone in the Arctic lower stratosphere during the Airborne Arctic Stratospheric Expedition II (AASE II) in the winter of 1991-1992. The analysis indicates removal of 15 to 20 percent of ambient ozone because of elevated concentrations of chlorine monoxide and bromine monoxide. Observations during AASE II define rates of removal of chlorine monoxide attributable to reaction with nitrogen dioxide (produced by photolysis of nitric acid) and to production of hydrochloric acid. Ozone loss ceased in March as concentrations of chlorine monoxide declined. Ozone losses could approach 50 percent if regeneration of nitrogen dioxide were inhibited by irreversible removal of nitrogen oxides (denitrification), as presently observed in the Antarctic, or without denitrification if inorganic chlorine concentrations were to double.

  7. Chemical loss of ozone in the Arctic polar vortex in the winter of 1991- 1992

    NASA Technical Reports Server (NTRS)

    Salawitch, R. J.; Wofsy, S. C.; Gottlieb, E. W.; Lait, L. R.; Newman, P. A.; Schoeberl, M. R.; Loewenstein, M.; Podolske, J. R.; Strahan, S. E.; Proffitt, M. H.

    1993-01-01

    In situ measurements of chlorine monoxide, bromine monoxide, and ozone are extrapolated globally, with the use of meteorological tracers, to infer the loss rates for ozone in the Arctic lower stratosphere during the Airborne Arctic Stratospheric Expedition II (AASE II) in the winter of 1991-1992. The analysis indicates removal of 15 to 20 percent of ambient ozone because of elevated concentrations of chlorine monoxide and bromine monoxide. Observations during AASE II define rates of removal of chlorine monoxide attributable to reaction with nitrogen dioxide (produced by photolysis of nitric acid) and to production of hydrochloric acid. Ozone loss ceased in March as concentrations of chlorine monoxide declined. Ozone losses could approach 50 percent if regeneration of nitrogen dioxide were inhibited by irreversible removal of nitrogen oxides (denitrification), as presently observed in the Antarctic, or without denitrification if inorganic chlorine concentrations were to double.

  8. Titan's Winter Polar Vortex

    NASA Technical Reports Server (NTRS)

    Flasar, F.M.; Achterberg, R.K.; Schinder, P.J.

    2008-01-01

    Titan's atmosphere has provided an interesting study in contrasts and similarities with Earth's. While both have N$_2$ as the dominant constituent and comparable surface pressures $\\sim1$ bar, Titan's next most abundant molecule is CH$_4$, not O$_2$, and the dissociative breakup of CH$_4$ and N$_2$ by sunlight and electron impact leads to a suite of hydrocarbons and nitriles, and ultimately the photochemical smog that enshrouds the moon. In addition, with a 15.95-day period, Titan is a slow rotator compared to Earth. While the mean zonal terrestrial winds are geostrophic, Titan's are mostly cyclostrophic, whipping around the moon in as little as 1 day. Despite the different dynamical regime, Titan's winter stratosphere exhibits several characteristics that should be familiar to terrestrial meteorologists. The cold winter pole near the 1 -mbar level is circumscribed by strong winds (up to 190 m/s) that act as a barrier to mixing with airmasses at lower latitudes. There is evidence of enhancement of several organic species over the winter pole, indicating subsidence. The adiabatic heating associated with this subsidence gives rise to a warm anomaly at the 0.01-mbar level, raising the stratopause two scale heights above its location at equatorial latitudes. Condensate ices have been detected in Titan's lower stratosphere within the winter polar vortex from infrared spectra. Although not always unambiguously identified, their spatial distribution exhibits a sharp gradient, decreasing precipitously across the vortex away from the winter pole. The interesting question of whether there is important heterogeneous chemistry occurring within the polar vortex, analogous to that occurring in the terrestrial polar stratospheric clouds in the ozone holes, has not been addressed. The breakup of Titan's winter polar vortex has not yet been observed. On Earth, the polar vortex is nonlinearly disrupted by interaction with large-amplitude planetary waves. Large-scale waves have not been identified in Titan's atmosphere, so the decay of its polar vortex may be more gradual than on Earth. Observations from an extended Cassini mission into late northern spring should provide critical data indicating whether the vortex goes away with a bang or just fades away.

  9. Chemical definition of the mesospheric polar vortex

    NASA Astrophysics Data System (ADS)

    Harvey, V. L.; Randall, C. E.; Collins, R. L.

    2015-10-01

    We present a simple chemical definition to demark the edge of the mesospheric polar vortices. Because this vortex definition does not rely on the wind field, it is useful in the mesosphere where wind observations are sparse and reanalysis winds are unreliable. The chemical definition is also insensitive to double jets that complicate vortex identification in the mesosphere. The algorithm is based on horizontal gradients of carbon monoxide (CO) and mirrors the widely used vortex edge definition in the stratosphere based on potential vorticity (PV) gradients. Here the approach is used to identify the Arctic vortex in the mesosphere during a 10 year (2004-2014) record of Microwave Limb Sounder data. Vortex size and shape comparisons are made where the CO and PV methods overlap in the upper stratosphere. A case study is presented during the NH 2008-2009 winter that demonstrates the fidelity of the CO gradient method on individual days and emphasizes the impact of double jets on methods to identify the polar vortex. We recommend transitioning from a PV or stream function-based vortex definition in the stratosphere to using a CO gradient definition above 0.1 hPa (~60 km). The CO gradient method identifies a coherent region of high CO at 80 km that is confined to mid-to-high latitudes 99.8% of the time during Arctic winter. Taking advantage of the CO gradient method to identify the polar vortex adds ~20 km of reliable vortex information (from 60 to 80 km) in a region of the atmosphere where reanalyses are most suspect.

  10. The Arctic Vortex in March 2011: A Dynamical Perspective

    NASA Technical Reports Server (NTRS)

    Hurwitz, Margaret M.; Newman, Paul A.; Garfinkel,Chaim I.

    2011-01-01

    Despite the record ozone loss observed in March 2011, dynamical conditions in the Arctic stratosphere were unusual but not unprecedented. Weak planetary wave driving in February preceded cold anomalies in t he polar lower stratosphere in March and a relatively late breakup of the Arctic vortex in April. La Nina conditions and the westerly phas e of the quasi-biennial oscillation (QBO) were observed in March 201 1. Though these conditions are generally associated with a stronger vortex in mid-winter, the respective cold anomalies do not persist t hrough March. Therefore, the La Nina and QBO-westerly conditions cannot explain the observed cold anomalies in March 2011. In contrast, po sitive sea surface temperature anomalies in the North Pacific may ha ve contributed to the unusually weak tropospheric wave driving and s trong Arctic vortex in late winter 2011.

  11. Sub-Monthly Polar Vortex Variability and Stratosphere-Troposphere Coupling

    E-print Network

    Black, Robert X.

    Sub-Monthly Polar Vortex Variability and Stratosphere-Troposphere Coupling in the Arctic Robert X in the boreal stratospheric polar vortex. Compared to previous studies, the current analysis examines daily zonal-mean variability within a limited spatial domain encompassing the stratospheric polar vortex

  12. Statistical characterization of arctic polar-night jet oscillation events

    E-print Network

    Wirosoetisno, Djoko

    of the Arctic stratospheric polar vortex over multiple decades. This visualization illustrates the ubiquity of extended-time-scale recoveries from stratospheric sudden warmings, termed here polar-night jet oscillation (PJO) events. These are characterized by an anomalously warm polar lower stratosphere that persists

  13. Chemical Observations of a Polar Vortex Intrusion

    NASA Technical Reports Server (NTRS)

    Schoeberl, M. R.; Kawa, S. R.; Douglass, A. R.; McGee, T. J.; Browell, E.; Waters, J.; Livesey, N.; Read, W.; Froidevaux, L.

    2006-01-01

    An intrusion of vortex edge air in D the interior of the Arctic polar vortex was observed on the January 31,2005 flight of the NASA DC-8 aircraft. This intrusion was identified as anomalously high values of ozone by the AROTAL and DIAL lidars. Our analysis shows that this intrusion formed when a blocking feature near Iceland collapsed, allowing edge air to sweep into the vortex interior. along the DC-8 flight track also shows the intrusion in both ozone and HNO3. Polar Stratospheric Clouds (PSCs) were observed by the DIAL lidar on the DC-8. The spatial variability of the PSCs can be explained using MLS HNO3 and H2O observations and meteorological analysis temperatures. We also estimate vortex denitrification using the relationship between N2O and HNO3. Reverse domain fill back trajectory calculations are used to focus on the features in the MLS data. The trajectory results improve the agreement between lidar measured ozone and MLS ozone and also improve the agreement between the HNO3 measurements PSC locations. The back trajectory calculations allow us to compute the local denitrification rate and reduction of HCl within the filament. We estimate a denitrification rate of about lO%/day after exposure to below PSC formation temperature. Analysis of Aura MLS observations made

  14. Quantifying Subsidence in the 1999-2000 Arctic Winter Vortex

    NASA Technical Reports Server (NTRS)

    Greenblatt, Jeffery B.; Jost, Hans-juerg; Loewenstein, Max; Podolske, James R.; Bui, T. Paul; Elkins, James W.; Moore, Fred L.; Ray, Eric A.; Sen, Bhaswar; Margitan, James J.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    Quantifying the subsidence of the polar winter stratospheric vortex is essential to the analysis of ozone depletion, as chemical destruction often occurs against a large, altitude-dependent background ozone concentration. Using N2O measurements made during SOLVE on a variety of platforms (ER-2, in-situ balloon and remote balloon), the 1999-2000 Arctic winter subsidence is determined from N2O-potential temperature correlations along several N2O isopleths. The subsidence rates are compared to those determined in other winters, and comparison is also made with results from the SLIMCAT stratospheric chemical transport model.

  15. The potential for ozone depletion in the Arctic polar stratosphere

    SciTech Connect

    Brune, W.H. ); Anderson, J.G.; Toohey, D.W. ); Fahey, D.W.; Kawa, S.R. ); Jones, R.L. ); McKenna, D.S. ); Poole, L.R. )

    1991-05-31

    The nature of the Arctic polar stratosphere is observed to be similar in many respects to that of the Antarctic polar stratosphere, where an ozone hole has been identified. most of the available chlorine (HCl and ClONO{sub 2}) was converted by reactions on polar stratospheric clouds to reactive ClO and Cl{sub 2}O{sub 2} throughout the Arctic polar vortex before midwinter. Reactive nitrogen was converted to HNO{sub 3}, and some, with spatial inhomogeneity, fell out of the stratosphere. These chemical changes ensured characteristic ozone losses of 10 to 15% at altitudes inside the polar vortex where polar stratospheric clouds had occurred. These local losses can translate into 5 to 8% losses in the vertical column abundance of ozone. As the amount of stratospheric chlorine inevitably increases by 50% over the next two decades, ozone losses recognizable as an ozone hole may well appear.

  16. Trace Gas Transport in the Arctic Vortex Inferred from ATMOS ATLAS-2 Observations During April 1993

    NASA Technical Reports Server (NTRS)

    Abrams, M. C.; Manney, G. L.; Gunson, M. R.; Abbas, M. M.; Chang, A. Y.; Goldman, A.; Irion, F. W.; Michelsen, H. A.; Newchurch, M. J.; Rinsland, C, P,; Salawitch, R. J.; Stiller, G. P.; Zander, R.

    1996-01-01

    Measurements of the long-lived tracers CH4, N2O, and HF from the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument during the Atmospheric Laboratory for Science and Applications-2 (ATLAS-2) Space Shuttle mission in April 1993 are used to infer average winter descent rates ranging from 0.8 km/month at 20 km to 3.2 km/month at 40 km in the Arctic polar vortex during the 1992-93 winter. Descent rates in the mid-stratosphere are similar to those deduced for the Antarctic vortex using ATMOS/ATLAS-3 measurements in November 1994, but the shorter time period of descent in the Arctic leads to smaller total distances of descent. Strong horizontal gradients observed along the vortex edge indicate that the Arctic vortex remains a significant barrier to transport at least until mid-April in the lower to middle stratosphere.

  17. In situ observations of HO2 and OH obtained on the NASA ER-2 in the high-ClO conditions of the 1999/2000 Arctic polar vortex

    NASA Astrophysics Data System (ADS)

    Hanisco, T. F.; Smith, J. B.; Stimpfle, R. M.; Wilmouth, D. M.; Anderson, J. G.; Richard, E. C.; Bui, T. P.

    2002-10-01

    Extensive observations of OH and HO2 obtained aboard the NASA ER-2 inside the Arctic polar vortex during the SAGE III Ozone loss and Validation Experiment (SOLVE) provide the opportunity to identify and test interferences during the measurement of HO2 in the presence of high concentrations of ClO. In-flight calibrations are consistent with small interferences from CH3O2 (8%) and from ClO (3%) to the total signal on average inside the vortex. Measurements of HO2, OH, ClO, and O3 are used with rate constants derived from laboratory measurements to test the consistency of the reactions that control HO2/OH. Inside the vortex the calculated HO2/OH under predicts the observed HO2/OH by 7% with the JPL-00 rate constants and over-predicts the observations by 23% when recent laboratory rates are used. Measurements of HO2 and ClO are used to calculate ozone loss rates and concentrations of HOCl with uncertainties determined from the analysis of HO2/OH. The calculated concentration of HOCl is 52-28+50 pptv, or 0.07 × ClO on average in the vortex. The ozone loss rate from the two cycles controlled by HO2 + ClO is ˜1.5-0.5+1.2 ppbv d-1 in early March.

  18. Transport out of the lower stratospheric Arctic vortex by Rossby wave breaking

    NASA Technical Reports Server (NTRS)

    Waugh, D. W.; Plumb, R. A.; Atkinson, R. J.; Schoeberl, M. R.; Lait, L. R.; Newman, P. A.; Loewenstein, M.; Toohey, D. W.; Avallone, L. M.; Webster, C. R.

    1994-01-01

    The fine-scale structure in lower stratospheric tracer transport during the period of the two Arctic Airborne Stratospheric Expeditions (January and February 1989; December 1991 to March 1992) is investigated using contour advection with surgery calculations. These calculations show that Rossby wave breaking is an ongoing occurrence during these periods and that air is ejected from the polar vortex in the form of long filamentary structures. There is good qualitative agreement between these filaments and measurements of chemical tracers taken aboard the NASA ER-2 aircraft. The ejected air generally remains filamentary and is stretched and mixed with midlatitude air as it is wrapped around the vortex. This process transfers vortex air into midlatitudes and also produces a narrow region of fine-scale filaments surrounding the polar vortex. Among other things, this makes it difficult to define a vortex edge. The calculations also show that strong stirring can occur inside as well as outside the vortex.

  19. The structure of the polar vortex

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.; Lait, Leslie R.; Newman, Paul A.; Rosenfield, Joan E.

    1992-01-01

    The paper develops a comparative picture of the 1987 Southern Hemisphere and 1989 Northern Hemisphere lower stratospheric, polar vortex circulation and constituent distributions as observed by the Airborne Antarctic Ozone Experiment, August 17-September 22, 1987, and Airborne Arctic Stratospheric Expedition, January 3-February 19, 1989 aircraft campaigns. Overall, both polar vortices define a region of highly isolated air, where the exchange of trace gases occurs principally at the vortex edge through erosional wave activity. Aircraft measurement showed that between 50 and 100 mbar, horizontally stratified long-lived tracers such as N2O are displaced downward 2-3 km on the cyclonic (poleward) side of the jet with the meridional tracer gradient sharpest at the jet core. Eddy mixing rates, computed using parcel ensemble statistics, are an order of magnitude or more lower on the cyclonic side of the jet compared to those on the anticyclonic side. Poleward zonal mean meridional flow on the anticyclonic side of the jet terminates in a descent zone at the jet core.

  20. N2O as a dynamical tracer in the Arctic vortex

    NASA Technical Reports Server (NTRS)

    Loewenstein, M.; Podolske, J. R.; Chan, K. R.; Strahan, S. E.

    1990-01-01

    This paper reports N2O measurements obtained by the Airborne Tunable Laser Absorption Spectrometer from 14 flights of the NASA ER-2 aircraft during the 1989 Airborne Arctic Stratospheric Expedition field campaign. In the altitude range expected for ozone loss, N2O has a long photochemical lifetime, making it an excellent tracer of lower stratospheric air motions. As in the southern hemisphere, the zonal wind speed maximum and large gradients of potential vorticity and N2O identify the vortex edge. The N2O profiles inside the vortex indicate net descent relative to outside the vortex and to the summer polar lower stratosphere. The descent of the N2O profile during the Arctic night relative to the summer profile is comparable to the downward shift in the vertical profile observed in the 1987 Antarctic winter vortex. Winter profiles at the poles are very similar above the 435 K potential temperature surface, but divergent below.

  1. The variability of ClONO{sub 2} and HNO{sub 3} in the Arctic polar vortex: Comparison of Transall Michelso interferometer for passive atmospheric sounding measurements and three-dimensional model results

    SciTech Connect

    Chipperfield, M.P.; Pyle, J.A.; Blom, C.E.

    1995-05-20

    The authors compare aircraft based infrared measurements of column amounts of nitric acid and chlorine nitrate in the northern European stratosphere with a three-dimensional stratospheric model which incorporates detailed chemical reactions, including heterogeneous processing effects on polar stratospheric clouds. In particular the authors compare the model and measurements in the region of the polar vortex, where during late January the measurements showed a marked gradient of chlorine nitrate across the vortex. This is consistent with model results which indicate strong horizontal gradients. The model has fairly coarse resolution and could not well reproduce the variation through the vortex where observed gradient were quite large. In March, with the appearance of distortions in the polar vortex, the experiment showed high densities of chlorine nitrate at high altitudes at the northern latitudes, and as one moved south in the polar vortex, the densities increased at lower altitudes. This is consistent with model predictions when the vortex begins to distort.

  2. Microphysical properties of synoptic-scale polar stratospheric clouds: in situ measurements of unexpectedly large HNO3-containing particles in the Arctic vortex

    NASA Astrophysics Data System (ADS)

    Molleker, S.; Borrmann, S.; Schlager, H.; Luo, B.; Frey, W.; Klingebiel, M.; Weigel, R.; Ebert, M.; Mitev, V.; Matthey, R.; Woiwode, W.; Oelhaf, H.; Dörnbrack, A.; Stratmann, G.; Grooß, J.-U.; Günther, G.; Vogel, B.; Müller, R.; Krämer, M.; Meyer, J.; Cairo, F.

    2014-10-01

    In January 2010 and December 2011, synoptic-scale polar stratospheric cloud (PSC) fields were probed during seven flights of the high-altitude research aircraft M-55 Geophysica within the RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interaction) and the ESSenCe (ESSenCe: ESA Sounder Campaign) projects. Particle size distributions in a diameter range between 0.46 and 40?m were recorded by four different optical in situ instruments. Three of these particle instruments are based on the detection of forward-scattered light by single particles. The fourth instrument is a grayscale optical array imaging probe. Optical particle diameters of up to 35?m were detected with particle number densities and total particle volumes exceeding previous Arctic measurements. Also, gas-phase and particle-bound NOy was measured, as well as water vapor concentrations. The optical characteristics of the clouds were measured by the remote sensing lidar MAL (Miniature Aerosol Lidar) and by the in situ backscatter sonde MAS (Multiwavelength Aerosol Scatterometer), showing the synoptic scale of the encountered PSCs. The particle mode below 2?m in size diameter has been identified as supercooled ternary solution (STS) droplets. The PSC particles in the size range above 2?m in diameter are considered to consist of nitric acid hydrates, and the particles' high HNO3 content was confirmed by the NOy instrument. Assuming a particle composition of nitric acid trihydrate (NAT), the optically measured size distributions result in particle-phase HNO3 mixing ratios exceeding available stratospheric values. Therefore the measurement uncertainties concerning probable overestimations of measured particle sizes and volumes are discussed in detail. We hypothesize that either a strong asphericity or an alternate particle composition (e.g., water ice coated with NAT) could explain our observations. In particular, with respect to the denitrification by sedimentation of large HNO3-containing particles, generally considered to be NAT, our new measurements raise questions concerning composition, shape and nucleation pathways. Answering these would improve the numerical simulation of PSC microphysical processes like cloud particle formation, growth and denitrification, which is necessary for better predictions of future polar ozone losses, especially under changing global climate conditions. Generally, it seems that the occurrence of large NAT particles - sometimes termed "NAT rocks" - are a regular feature of synoptic-scale PSCs in the Arctic.

  3. On the Origin of Polar Vortex Air

    NASA Technical Reports Server (NTRS)

    Rosenfield, J. E.; Schoeberl, M. R.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The existence of the multi-year HALOE CH4 data set, together with some comparisons of forward with back trajectory calculations which we have carried out, has motivated us to reexamine the question of polar vortex descent. Three-dimensional diabatic trajectory calculations have been carried out for the seven month fall to spring period in both the northern hemisphere (NH) and southern hemisphere (SH) polar stratosphere for the years 1992-1999. These computations are compared to fixed descent computations where the parcels were fixed at their latitude-longitude locations and allowed to descend without circulating. The forward trajectory computed descent is always less than the fixed descent due to horizontal parcel motions and variations in heating rates with latitude and longitude. Although the forward calculations estimate the maximum amount of descent that can occur, they do not necessarily indicate the actual origin of springtime vortex air. This is because more equator-ward air can be entrained within the vortex during its formation. To examine the origin of the springtime vortex air, the trajectory model was run backward for seven months from spring to fall. The back trajectories show a complex distribution of parcels in which one population originates in the upper stratosphere and mesosphere and experiences considerable descent in the polar regions, while the remaining parcels originate at lower altitudes of the middle and lower stratosphere and are mixed into the polar regions during vortex formation without experiencing as much vertical transport. The amount of descent experienced by the first population shows little variability from year to year, while the computed descent and mixing of the remaining parcels show considerable interannual variability due to the varying polar meteorology. Because of this complex parcel distribution it is not meaningful to speak of a net amount of descent experienced over the entire winter period. Since the back trajectories indicate that much of the air can come from lower altitudes than would be implied by the forward calculations, using a comparison between pre-winter and post-winter tracer profiles to estimate the amount of descent over this period will give erroneous descent amounts. In order to evaluate the computed descent, spring methane amounts were computed by mapping HALOE fall observations onto the final latitude-altitude locations of the back trajectories. These locations indicate the origin of the spring vortex air. The agreement between the computed means and the spring HALOE means is generally within 0.1-0.2 ppmv in the NH and 0.1-0.4 ppmv in the SH.

  4. Loss of ozone in the Arctic vortex for the winter of 1989

    SciTech Connect

    Salawitch, R.J.; McElroy, M.B.; Yatteau, J.H.; Wofsy, S.C. ); Schoeberl, M.R.; Lait, L.R.; Newman, P.A. ); Chan, K.R.; Loewenstein, M.; Podolske, J.R.; Strahan, S.E. ); Proffitt, M.H. Univ. of Colorado, Boulder )

    1990-03-01

    Measurements of ClO (Brune et al., 1990) acquired during the Airborne Arctic Stratospheric Expedition are used to infer concentrations of reactive chlorine (ClO + 2 {times} Cl{sub 2}O{sub 2}). Observed fields of potential temperature and potential vorticity are used to extrapolate in situ data to larger regions of the vortex. Calculated values of the loss rate of O{sub 3}, based on estimates of reactive chlorine and measurements of BrO (Toohey et al., 1990), suggest that the loss of O{sub 3} was about 12% for levels of the atmosphere with potential temperatures between 440 and 470 K over the 39 day duration of the ER-2 flights into the polar vortex. Calculated loss rates agree with observed rates of removal of O{sub 3}, although significant uncertainties exist for each.

  5. Loss of ozone in the Arctic vortex for the winter of 1989

    NASA Technical Reports Server (NTRS)

    Salawitch, Ross J.; Mcelroy, Michael B.; Yatteau, John H.; Schoeberl, Mark R.; Lait, Leslie R.; Newman, Paul A.; Chan, K. Roland; Loewenstein, Max; Podolske, James R.; Strahan, Susan E.

    1990-01-01

    Measurements of ClO (Brune et al., 1990) acquired during the Airborne Arctic Stratospheric Expedition are used to infer concentrations of reactive chlorine (ClO + 2 x Cl2O2). Observed fields of potential temperature and potential vorticity are used to extrapolate in situ data to larger regions of the vortex. Calculated values of the loss rate of O3, based on estimates of reactive chlorine and measurements of BrO (Toohey et al., 1990), suggest that the loss of O3 was abut 12 pct for levels of the atmosphere with potential temperatures between 440 and 470 K over the 39 day duration of the ER-2 flights into the polar vortex. Calculated loss rates agree with observed rates of removal of O3, although significant uncertainties exist for each.

  6. Chemical chhange in the arctic vortex during AASE 2

    NASA Astrophysics Data System (ADS)

    Traub, Wesley A.; Jucks, Kenneth W.; Johnson, David G.; Chance, Kelly V.

    1994-11-01

    We measured column abundances of HF, HCl, O3, HNO3, and H2O on the NASA DC-8 during the AASE II campaign, using thermal emission spectroscopy. We made multiple traversals of the Arctic vortex and surroundings. Using HF as a tracer, we remove the effects of subsidence from the measured column abundances; perturbations in the resulting column abundances are attributed to chemical processing. We find that by January 1992 the stratospheric column in the vortex had been chemically depleted by about (55+/-10)% in HCl and (35+/-10)% in O3, and enhanced by about (15+/-10)% in HNO3 and (0+/-10)% in H2O.

  7. Intrusions into the lower stratospheric Arctic vortex during the winter of 1991-1992

    NASA Technical Reports Server (NTRS)

    Plumb, R. A.; Waugh, D. W.; Atkinson, R. J.; Newman, P. A.; Lait, L. R.; Schoeberl, M. R.; Browell, E. V.; Simmons, A. J.; Loewenstein, M.

    1994-01-01

    Investigations of the kinematics of the lower stratospheric Arctic vortex during the winter of 1991-1992 using the contour advection with surgery technique reveal three distinct events in which there was substantial intrusion of midlatitude air into the vortex, in apparent contradiction of the view that the polar vortex constitutes an isolated air mass. Two of these events, in late January and mid-February, were well documented. They were predicted in high-resolution forecasts by the European Centre for Medium-Range Weather Forecasts, most clearly in experimental forecasts with reduced diffusion. Direct confirmation of the presence of the intrusions and of their calculated locations was provided by aerosol observations from the airborne differential absorption laser lidar aboard the NASA DC-8, taken as part of the second Airborne Arctic Stratospheric Expedition campaign; aerosol-rich air of midlatitude origin was seen in the expected position of the intrusions. The reality of the February event was also confirmed by in situ measurements from the NASA ER-2. Such events may be significant for the chemical processes taking place within the winter vortex. The intrusions were evidently related to the meteorology of the northern stratosphere during this winter and in particular to persistent tropospheric blocking over the northeastern Atlantic Ocean and western Europe and concomitant ridging into the lower stratospheric vortex in this region. Nevertheless, preliminary investigations have indicated that such events are not uncommon in other northern hemisphere winters, although no such events were found in the southern hemisphere during the Antarctic winter of 1987.

  8. Volcanoes, Polar Clouds and Arctic Ozone

    NASA Technical Reports Server (NTRS)

    Tabazadeh, Azadeh; Gore, Warren J. (Technical Monitor)

    2001-01-01

    Satellite observations and model calculations show 5 to 10% local column ozone loss in some tropical and mid latitude locations, following El Chichon and Mount Pinatubo eruptions. The rapid deepening of the Antarctic ozone hole in the early 1980s has also been partially attributed to chemistry on volcanic aerosols from a number of large eruptions. Here the effects of volcanoes on Arctic polar processes are explored. Large polar stratospheric cloud particles that cause denitrification cannot form in a volcanically perturbed environment. Denitrification can increase Arctic ozone loss by up to 30% in a future colder climate. However, we show that enhanced chemical processing on volcanic aerosols can increase Arctic ozone loss in a cold year by about 60% independent of denitrification. A coupled chemistry-microphysics model is used to show that widespread distribution of volcanic aerosols in 2000 could have caused severe springtime ozone depletion in the Arctic stratosphere. While, volcanic aerosols can strongly affect the current Arctic column ozone abundance in a cold year, denitrification effects on ozone can only become important in a much colder lower stratosphere.

  9. Polar Stratospheric Descent of NO(y) and CO and Arctic Denitrification During Winter 1992-1993

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Salawitch, R. J.; Gunson, M. R.; Solomon, S.; Zander, R.; Mahieu, E.; Goldman, A.; Newchurch, M. J.; Irion, F. W.; Chang, A. Y.

    1999-01-01

    Observations inside the November 1994 Antarctic stratospheric vortex and inside the April 1993 remnant Arctic stratospheric vortex by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer are reported. In both instances, elevated volume mixing ratios (VMRS) of carbon monoxide (CO) were measured. A peak Antarctic CO VMR of 60 ppbv (where 1 ppbv = 10(exp -9) per unit Volume) was measured at a potential temperature of 710 K (about 27 km), about 1 km below the altitude of a pocket of elevated NO(y) (total reactive nitrogen) at a deep minimum in N2O (<5 ppbv). The Arctic observations also show a region of elevated vortex CO with a peak VMR of 90 ppbv it 630-670 K (-25 km) but no corresponding enhancement in NO(sub y) perhaps because of stronger dynamical activity in the northern hemisphere polar winter and/or interannual variability in the production of mesospheric or lower thermospheric NO. By comparing vortex and extravortex observations of NO(y) obtained at the same N2O VMR, Arctic vortex denitrification of 5 +/- 2 ppbv at 470 K (at approximately 18 km) is inferred. We show that our conclusion of substantial Arctic winter 1992-1993 denitrification is robust by comparing our extravortex observations with previous polar measurements obtained over a wide range of winter conditions. Correlations of NO(y) with N2O measured at the same potential temperature by ATMOS in the Arctic vortex and at midlatitudes on board the ER-2 aircraft several weeks later lie along the same mixing line. The result demonstrates the consistency of the two data sets and confirms that the ER-2 sampled fragments of the denitrified Arctic vortex following its breakup. An analysis of the ATMOS Arctic measurements of total hydrogen shows no evidence for significant dehydration inside the vortex.

  10. Volcanic aerosol and polar stratospheric clouds in the winter 1992/93 north polar vortex

    SciTech Connect

    Rosen, J.M.; Kjome, N.T. ); Fast, H. ); Larsen, N. )

    1994-01-01

    Backscatter profiles were measured at 940 and 490 nm in the winter north polar vortex using balloon borne backscattersondes. There was no mid-season breakdown of the vortex, and temperatures were sufficiently cold to expect the formation of polar stratospheric clouds (PSCs). The mass loading from the Mount Pinatubo aerosols inside the vortex was observed to be larger than that of the previous year and equivalent to about 20 megatonnes if spread uniformly over the earth. The positive identification of typical PSCs was made more difficult by the presence of considerable volcanic aerosol background. An unusual scattering layer that can probably be identified as some type of PSC was not associated with as much backscatter as observed in previous non-volcanic years with similar stratospheric temperatures. The layer apparently was composed of comparatively large particles with a relatively low, highly variable number concentration and was easily identified by the enhancement in fine structure of the scattering properties rather than an outstanding increase in average scattering values. The arctic volcanic aerosol layer was found to produce a small but significant depolarized backscattered signal. This preliminary results could be interpreted as indicating the presence of some non-spherical particles (perhaps due to freezing effects) and/or spherical particles containing inclusions of irregular shapes with differing refractive index. 9 refs., 5 figs.

  11. Evolution of the 1991-1992 Arctic vortex and comparison with the Geophysical Fluid Dynamics Laboratory SKYHI general circulation model

    NASA Technical Reports Server (NTRS)

    Strahan, S. E.; Rosenfield, J. E.; Loewenstein, M.; Podolske, J. R.; Weaver, A.

    1994-01-01

    Nitrous oxide (N2O) measured on board the ER-2 aircraft during the Airborne Arctic Stratospheric Expedition 2 (AASE 2) has been used to monitor descent of air inside the Arctic vortex between October 1991 and March 1992. Monthly mean N2O fields are calculated from the flight data and then compared with mean fields calculated from the high-resolution Geophysical Fluid Dynamics Laboratory general circulation model SKYHI in order to evaluate the model's simulation of the polar vortex. From late fall through winter the model vortex evolves in much the same way as the 1991-1992 vortex, with N2O gradients at the edge becoming progressively steeper. The October to March trends in N2O profiles inside the vortex are used to verify daily net heating rates in the vortex that were computed from clear sky radiative heating rates and National Meteorological Center temperature observations. The computed heating rates successfully estimate the descent of vortex air from December through February but suggest that before December, air at high latitudes may not be isolated from the midlatitudes. SKYHI heating rates are in good agreement with the computed rates but tend to be slightly higher (i.e., less cooling) due to meteorological differences between SKYHI and the 1991-1992 winter. Three ER-2 flights measured N2O just north of the subtropical jet. These low-midlatitude profiles show only slight differences from the high-midlatitude profiles (45 deg - 60 deg N), indicating strong meridional mixing in the midlatitude 'surf zone.' Mean midwinter N2O profiles inside and outside the vortex calculated from AASE 2 data are shown to be nearly identical to 1989 AASE profiles, pointing to the N2O/potential temperature relationship as an excellent marker for vortex air.

  12. Effect of Recent Sea Surface Temperature Trends on the Arctic Stratospheric Vortex

    NASA Technical Reports Server (NTRS)

    Garfinkel, Chaim I.; Oman, Luke; Hurwitz, Margaret

    2015-01-01

    The springtime Arctic polar vortex has cooled significantly over the satellite era, with consequences for ozone concentrations in the springtime transition season. The causes of this cooling trend are deduced by using comprehensive chemistry-climate model experiments. Approximately half of the satellite era early springtime cooling trend in the Arctic lower stratosphere was caused by changing sea surface temperatures (SSTs). An ensemble of experiments forced only by changing SSTs is compared to an ensemble of experiments in which both the observed SSTs and chemically- and radiatively-active trace species are changing. By comparing the two ensembles, it is shown that warming of Indian Ocean, North Pacific, and North Atlantic SSTs, and cooling of the tropical Pacific, have strongly contributed to recent polar stratospheric cooling in late winter and early spring, and to a weak polar stratospheric warming in early winter. When concentrations of ozone-depleting substances and greenhouse gases are fixed, polar ozone concentrations show a small but robust decline due to changing SSTs. Ozone changes are magnified in the presence of changing gas concentrations. The stratospheric changes can be understood by examining the tropospheric height and heat flux anomalies generated by the anomalous SSTs. Finally, recent SST changes have contributed to a decrease in the frequency of late winter stratospheric sudden warmings.

  13. Hyperbolic lines and the stratospheric polar vortex.

    PubMed

    Koh, Tieh-Yong; Legras, Bernard

    2002-06-01

    The necessary and sufficient conditions for Lagrangian hyperbolicity recently derived in the literature are reviewed in the light of older concepts of effective local rotation in strain coordinates. In particular, we introduce the simple interpretation of the necessary condition as a constraint on the local angular displacement in strain coordinates. These mathematically rigorous conditions are applied to the winter stratospheric circulation of the southern hemisphere, using analyzed wind data from the European Center for Medium-Range Weather Forecasts. Our results demonstrate that the sufficient condition is too strong and the necessary condition is too weak, so that both conditions fail to identify hyperbolic lines in the stratosphere. However a phenomenological, nonrigorous, criterion based on the necessary condition reveals the hyperbolic structure of the flow. Another (still nonrigorous) alternative is the finite-size Lyapunov exponent (FSLE) which is shown to produce good candidates for hyperbolic lines. In addition, we also tested the sufficient condition for Lagrangian ellipticity and found that it is too weak to detect elliptic coherent structures (ECS) in the stratosphere, of which the polar vortex is an obvious candidate. Yet, the FSLE method reveals a clear ECS-like barrier to mixing along the polar vortex edge. Further theoretical advancement is needed to explain the apparent success of nonrigorous methods, such as the FSLE approach, so as to achieve a sound kinematic understanding of chaotic mixing in the winter stratosphere and other geophysical flows. (c) 2002 American Institute of Physics. PMID:12779568

  14. Arctic polar stratospheric cloud observations by airborne lidar

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Poole, L. R.; Kent, G. S.; Hunt, W. H.; Osborn, M. T.

    1990-01-01

    Lidar observations obtained from January 24 to February 2, 1989, during the Airborne Arctic Stratospheric expedition (AASE) mission further support the existence of two distinct classes (Types 1 and 2) of polar stratospheric clouds (PSCs). Most of the Type 1 PSCs observed were formed by rapid adiabatic cooling and exhibited very low depolarization ratios and low-to-intermediate scattering ratios. Type 2 PSCs were observed in regions of lowest temperature and showed much larger depolarization and scattering ratios, as would be expected from larger ice crystals. PSCs with low scattering ratios but moderate depolarization ratios were observed near the center of the vortex on one flight. These may have been either sparse Type 2 PSCs or Type 1 PSCs formed by less rapid cooling.

  15. Arctic polar stratospheric cloud observations by airborne lidar

    SciTech Connect

    McCormick, M.P.; Poole, L.R. ); Kent, G.S. ); Hunt, W.H. ); Osborn, M.T.; Pitts, M.C. )

    1990-03-01

    Lidar observations obtained from January 24 to February 2, 1989, during the Airborne Arctic Stratospheric Expedition (AASE) mission further support the existence of two distinct classes (Types 1 and 2) of polar stratospheric clouds (PSCs). Most of the Type 1 PSCs observed were formed by rapid adiabatic cooling and exhibited very low depolarization ratios and low-to-intermediate scattering ratios. Type 2 PSCs were observed in regions of lowest temperature and showed much larger depolarization and scattering ratios, as would be expected from larger ice crystals. PSCs with low scattering ratios but moderate depolarization ratios were observed near the center of the vortex on one flight. These may have been either sparse Type 2 PSCs or Type 1 PSCs formed by less rapid cooling.

  16. The Yearly Variation in Fall-Winter Arctic Winter Vortex Descent

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.; Newman, Paul A.

    1999-01-01

    Using the change in HALOE methane profiles from early September to late March, we have estimated the minimum amount of diabatic descent within the polar which takes place during Arctic winter. The year to year variations are a result in the year to year variations in stratospheric wave activity which (1) modify the temperature of the vortex and thus the cooling rate; (2) reduce the apparent descent by mixing high amounts of methane into the vortex. The peak descent amounts from HALOE methane vary from l0km -14km near the arrival altitude of 25 km. Using a diabatic trajectory calculation, we compare forward and backward trajectories over the course of the winter using UKMO assimilated stratospheric data. The forward calculation agrees fairly well with the observed descent. The backward calculation appears to be unable to produce the observed amount of descent, but this is only an apparent effect due to the density decrease in parcels with altitude. Finally we show the results for unmixed descent experiments - where the parcels are fixed in latitude and longitude and allowed to descend based on the local cooling rate. Unmixed descent is found to always exceed mixed descent, because when normal parcel motion is included, the path average cooling is always less than the cooling at a fixed polar point.

  17. Satellite observation of dehydration in the Arctic Polar stratosphere

    E-print Network

    Pan, Laura

    Satellite observation of dehydration in the Arctic Polar stratosphere L. L. Pan,1 W. J. Randel,1 H 2002. [1] We report the first space-borne observation of dehydration in the Arctic polar stratosphere Stratospheric Cloud (PSC) events. Furthermore, simultaneous observations of HNO3 and H2O show that the gas phase

  18. Titan's South Polar Vortex in Motion - Duration: 11 seconds.

    NASA Video Gallery

    This movie captured by NASA'S Cassini spacecraft shows a south polar vortex, or a swirling mass of gas around the pole in the atmosphere, at Saturnâ??s moon Titan. The swirling mass appears to exec...

  19. N2O as an indicator of Arctic vortex dynamics: Correlations with O3 over Thule, Greenland in February and March, 1992

    NASA Technical Reports Server (NTRS)

    Emmons, L. K.; Reeves, J. M.; Shindell, D. T.; De Zafra, R. L.

    1994-01-01

    We have recovered vertical profiles of stratospheric N2O from spectra observed using a ground-based mm-wave spectrometer during the Arctic spring. The measurements were made from Thule, Greenland (76.3 deg N, 68.4 deg W) on nine occasions from late February to late March, 1992 as part of the Upper Atmosphere Research Satellite (UARS) Correlative Measurements Program and the European Arctic Stratospheric Ozone Experiment (EASOE). During late February Thule was under inside edge of the Arctic vortex and mixing ratio profiles measured in that period are substantially reduced from typical high-latitude summer values. By late March the polar vortex had moved well away from Thule and N2O mixing ratios were greatly increased, coinciding with a basic change in circulation that brought in air from the Aleutian high. The motion of the vortex is also illustrated in the change in potential vorticity above Thule. A correlation with ozone balloonsonde data from Thule is made and compared to similar analyses of the Airborne Arctic Stratospheric Expedition (AASE) measurements. Within the sensitivity of our analysis, the correlation of N2O and O3 shows no evidence of ozone depletion within the vortex during this period; however, there is a distinct difference in the correlation inside and outside the vortex.

  20. Arctic polar stratospheric cloud measurements by means of a four wavelength depolarization lidar

    NASA Technical Reports Server (NTRS)

    Stefanutti, L.; Castagnoli, F.; Delguasta, M.; Flesia, C.; Godin, S.; Kolenda, J.; Kneipp, H.; Kyro, Esko; Matthey, R.; Morandi, M.

    1994-01-01

    A four wavelength depolarization backscattering lidar has been operated during the European Arctic Stratospheric Ozone Experiment (EASOE) in Sodankyl, in the Finnish Arctic. The lidar performed measurements during the months of December 1991, January, February and March 1992. The Finnish Meteorological Institute during the same period launched regularly three Radiosondes per day, and three Ozone sondes per week. Both Mt. Pinatubo aerosols and Polar Stratospheric Clouds were measured. The use of four wavelengths, respectively at 355 nm, 532 nm , 750 nm, and 850 nm permits an inversion of the lidar data to determine aerosol particle size. The depolarization technique permits the identification of Polar Stratospheric Clouds. Frequent correlation between Ozone minima and peaks in the Mt. Pinatubo aerosol maxima were detected. Measurements were carried out both within and outside the Polar Vortex.

  1. Nighttime OClO in the Winter Arctic Vortex

    NASA Technical Reports Server (NTRS)

    Canty, T.; Riviere, E. D.; Salawitch, R. J.; Berthet, G.; Renard, J. -B.; Pfeilsticker, K.; Dorf, M.; Butz, A.; Bosch, H.; Stimpfle, R. M.; Wilmouth, D. M.; Richard, E. C.; Fahey, D. W.; Popp, P. J.; Schoeberl, M. R.; Lait, L. R.; Bui, T. P.

    2005-01-01

    We show that a nighttime profile of OClO in the Arctic vortex during the winter of 2000 is overestimated, by nearly a factor of 2, using an isentropic trajectory model constrained by observed profiles of ClOx (ClO + 2 X ClOOCl) and BrO. Calculated abundances of nighttime OClO are shown to be sensitive to the abundance of BrOx (BrO + BrCl), details of the air parcel history during the most recent sunrise/sunset transitions, and the BrCl yield from the reaction BrO + ClO. Many uncertainties are considered, and the discrepancy between measured and modeled nighttime OClO appears to be robust. This discrepancy suggests that production of OClO occurs more slowly than implied by standard photochemistry. If the yield of BrCl from the reaction of BrO + ClO is increased from 7% (JPL 2002 value) to 11% (near the upper limit of the uncertainty), good agreement is found between measured and modeled nighttime OClO. This study highlights the importance of accurate knowledge of BrO + ClO reaction kinetics as well as air parcel trajectories for proper interpretation of nighttime OClO. These factors have a considerably smaller impact on the interpretation of OClO observations obtained during twilight (90(deg) <=SZA <= 92(deg)), when photolytic processes are still active.

  2. Potential Vorticity as a Diagnostic for the Mars Polar Vortex

    NASA Astrophysics Data System (ADS)

    McConnochie, T. H.; Conrath, B. J.; Gierasch, P. J.; Banfield, D.; Smith, M. D.

    2009-05-01

    Polar vortices dominate the dynamics of the winter mid- and polar latitudes in the martian atmosphere as well as in the terrestrial stratosphere. Polar vortices have also been observed on Venus (Taylor, 2002), Jupiter (Orton, 2002), Saturn (Fletcher, 2008), and Titan (Teanby, 2008). Potential vorticity is the analysis quantity of choice for the terrestrial polar vortices because its vertical component distills the most important features of the wind and temperature fields into a single scalar variable; because it is a conserved tracer under adiabatic conditions; because it serves as the medium for Rossby waves; and because steep potential vorticity gradients are observed to be correlated with steep gradients in the concentrations of chemical species. Using potential vorticity derived from Mars Global Surveyor Thermal Emission Spectrometer (TES) temperature soundings, we compare the structure of the martian polar vortices to those of the earth. We find that the northern martian winter polar vortex, just like its terrestrial conterpart, is bounded by a region of very steep potential vorticity gradients and is surrounded by a "surf zone", a region of low potential vorticity and very low potential vorticity gradients. The surf zone concept, as first described for the terrestrial stratosphere by McIntyre and Palmer (1983), implies persistent Rossby wave breaking. In the vicinity of the northern polar vortex, the TES data set provides some examples of local gradient reversals that are suggestive of wave breaking. There is also one case of possible large-scale wave breaking accompanied by an abrupt polar warming. The martian southern polar vortex, unlike its terrestrial counterpart and unlike the northern martian polar vortex, lacks a distinct boundary between the polar vortex and a surf zone. Instead, the potential vorticity field is highly disorganized with local gradient reversals throughout the middle and polar latitudes. In the zonal mean, the southern winter potential vorticity gradient ends up being relatively uniform, although it is somewhat enhanced near 60 degrees latitude.

  3. Occurrence of ozone laminae near the boundary of the stratospheric polar vortex

    SciTech Connect

    Reid, S.J.; Vaughan, G. ); Kyro, E. )

    1993-05-20

    The authors report on observations of laminae in ozone distributions observed at high northern latitudes near the polar vortex. Regions of enhanced and depleted ozone density are observed. Data from ozonesonde collections and lidar measurements during the Airborne Arctic Stratosphere Expedition (AASE) are analyzed, and compared with earlier work. The ozonesonde archives of the World Meteorological Organization are also examined in this analysis. The laminae are observed to distribute differently as a function of season, and with the potential temperature. Transport of ozone equatorward is also found with a class of these laminae.

  4. Airborne lidar observations in the wintertime Arctic stratosphere - Polar stratospheric clouds

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Ismail, S.; Carter, A. F.; Higdon, N. S.; Butler, C. F.; Robinette, P. A.; Toon, O. B.; Schoeberl, M. R.

    1990-01-01

    Polar stratospheric cloud (PSC) distributions in the wintertime Arctic stratosphere and their optical characteristics were measured with a multiwavelength airborne lidar system as part of the 1989 Airborne Arctic Stratospheric Expedition. PSCs were observed on 10 flights between January 6 and February 2, 1989, into the polar vortex. The PSCs were found in the 14-27 km altitude range in regions where the temperatures were less than 195 K. Two types of aerosols with different optical characteristics (Types 1a and 1b) were observed in PSCs thought to be composed of nitric acid trihydrate. Water ice PSCs (Type 2) were observed to have high scattering ratios (greater than 10) and high aerosol depolarizations (greater than 10 percent) at temperatures less than 190 K.

  5. On the motion of air through the stratospheric polar vortex

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Zurek, R. W.; O'Neill, A.; Swinbank, R.

    1994-01-01

    Trajectory calculations using horizontal winds from the U.K. Meteorological Office data assimilation system and vertical velocities from a radiation calculation are used to simulate the three-dimensional motion of air through the stratospheric polar vortex for Northern Hemisphere (NH) and Southern Hemisphere (SH) winters since the launch of the Upper Atmosphere Research Satellite (UARS). Throughout the winter, air from the upper stratosphere moves poleward and descends into the middle stratosphere. In the SH lower to middle stratosphere, strongest descent occurs near the edge of the polar vortex, with that edge defined by mixing characteristics. The NH shows a similar pattern in late winter, but in early winter strongest descent is near the center of the vortex, except when wave activity is particularly strong. Strong barriers to latitudinal mixing exist above about 420 K throughout the winter. Below this, the polar night jet is weak in early winter, so air descending below that level mixes between polar and middle latitudes. In late winter, parcels descend less and the polar night jet moves downward, so there is less latitudinal mixing. The degree of mixing in the lower stratosphere thus depends strongly on the position and evolution of the polar night jet and on the amount of descent experienced by the air parcels; these characteristics show considerable interannual variability in both hemispheres. The computed trajectories provide a three-dimensional picture of air motion during the final warming. Large tongues of air are drawn off the vortex and stretched into increasingly long and narrow tongues extending into low latitudes. This vortex erosion process proceeds more rapidly in the NH than in he SH. In the lower stratosphere, the majority of air parcels remain confined within a lingering region of strong potential vorticity gradients into December in the SH and April in the NH, well after the vortex breaks up in the midstratosphere.

  6. Rapid descent of mesospheric air into the stratospheric polar vortex

    SciTech Connect

    Fisher, M.; O'Neill, A.; Sutton, R.

    1993-06-18

    This paper describes simulations carried out to calculate the Lagrangian trajectories of greater than 40,000 air parcels in the middle atmospheric region of the southern polar vortex. The purpose was to see if model calculations would support recent observations which indicate that there is rapid vertical transport of air masses downward from the mesosphere into the stratospheric polar vortex. This conclusion was drawn from looking at the spatial distribution of long lived trace gases such as methane in the middle atmosphere. Looking at the Lagrangian fields provides a graphic picture of any mass motion, and does so in a fairly averaged manner.

  7. Optically induced rotation of Rayleigh particles by vortex beams with different states of polarization

    NASA Astrophysics Data System (ADS)

    Li, Manman; Yan, Shaohui; Yao, Baoli; Liang, Yansheng; Lei, Ming; Yang, Yanlong

    2016-01-01

    Optical vortex beams carry optical orbital angular momentum (OAM) and can induce an orbital motion of trapped particles in optical trapping. We show that the state of polarization (SOP) of vortex beams will affect the details of this optically induced orbital motion to some extent. Numerical results demonstrate that focusing the vortex beams with circular, radial or azimuthal polarizations can induce a uniform orbital motion on a trapped Rayleigh particle, while in the focal field of the vortex beam with linear polarization the particle experiences a non-uniform orbital motion. Among the formers, the vortex beam with circular polarization induces a maximum optical torque on the particle. Furthermore, by varying the topological charge of the vortex beams, the vortex beam with circular polarization gives rise to an optimum torque superior to those given by the other three vortex beams. These facts suggest that the circularly polarized vortex beam is more suitable for rotating particles.

  8. Response of the northern stratospheric polar vortex to the seasonal alignment of

    E-print Network

    Wirosoetisno, Djoko

    Response of the northern stratospheric polar vortex to the seasonal alignment of QBO phase stratospheric polar vortex to the seasonal alignment of QBO phase transitions. Geophysical Research Letters, 35 Reading's research outputs online #12;Response of the northern stratospheric polar vortex to the seasonal

  9. Different ENSO teleconnections and their effects on the stratospheric polar vortex

    E-print Network

    Garfinkel, Chaim I.

    Different ENSO teleconnections and their effects on the stratospheric polar vortex C. I. Garfinkel1. Hartmann (2008), Different ENSO teleconnections and their effects on the stratospheric polar vortex, J¨nnimann et al. [2004] found that El Nin~o affects the lower stratospheric polar vortex, and thus modi- fies

  10. Modelling the stratospheric polar vortex and its changes for GHGs increase and ozone depletion.

    E-print Network

    Greatbatch, Richard

    Modelling the stratospheric polar vortex and its changes for GHGs increase and ozone depletion and possible feedback of the stratospheric polar vortex to changes in GHGs and ozone, as simulated by general of the stratospheric polar vortex and its possible impacts on the troposphere? #12;Models · MAECHAM4: middle atmosphere

  11. Downward Wave Propagation on the Polar Vortex R. K. SCOTT* AND D. G. DRITSCHEL

    E-print Network

    Cambridge, University of

    of a stratospheric polar vortex, represented by a three-dimensional patch of uniform potential vorticity propagation on the edge of the winter stratospheric polar vortex. The subject of wave propa- gation and waveDownward Wave Propagation on the Polar Vortex R. K. SCOTT* AND D. G. DRITSCHEL School

  12. Effect of coma on tightly focused cylindrically polarized vortex beams

    NASA Astrophysics Data System (ADS)

    Therese Anita, G.; Umamageswari, N.; Prabakaran, K.; Pillai, T. V. S.; Rajesh, K. B.

    2016-01-01

    In this paper attention is given to the effects of primary coma on the cylindrical polarized vortex beam based on the vector diffraction theory. It is observed that by properly choosing the polarization angle and topological charge one can obtain many novel focal patterns suitable for optical tweezers, laser printing and material process. However, it is observed that the focusing objective with coma generates structural modification and positional shift of the generated focal structure.

  13. Vortex-wide chlorine activation by a mesoscale PSC event in the Arctic winter of 2009/10

    NASA Astrophysics Data System (ADS)

    Wegner, T.; Pitts, M. C.; Poole, L. R.; Tritscher, I.; Grooß, J.-U.; Nakajima, H.

    2015-11-01

    In the Arctic polar vortex of the 2009/10 winter temperatures were low enough to allow widespread formation of Polar Stratospheric Clouds (PSC). These clouds occurred during the initial chlorine activation phase which provided the opportunity to investigate the impact of PSCs on chlorine activation. Satellite observations of gas-phase species and PSCs are used in combination with trajectory modeling to assess this initial activation. The initial activation occurred in association with the formation of PSCs over the east coast of Greenland at the beginning of January 2010. Although this area of PSCs covered only a small portion of the vortex, it was responsible for almost the entire initial activation of chlorine vortex wide. Observations show HCl mixing ratios decreased rapidly in and downstream of this region. Trajectory calculations and simplified heterogeneous chemistry modeling confirmed that the initial chlorine activation continued until ClONO2 was completely depleted and the activated air masses were advected throughout the polar vortex. For the calculation of heterogeneous reaction rates, surface area density is estimated from backscatter observations. Modeled heterogeneous reaction rates along trajectories intersecting with the PSC indicate that the initial phase of chlorine activation occurred in just a few hours. These calculations also indicate that chlorine activation on the binary background aerosol is significantly slower than on the PSCs and the observed chlorine activation can only be explained by an increase in surface area density due to PSCs. Furthermore, there is a strong correlation between the magnitude of the observed HCl depletion and PSC surface area.

  14. Determination of the polarization states of an arbitrary polarized terahertz beam: Vectorial vortex analysis

    PubMed Central

    Wakayama, Toshitaka; Higashiguchi, Takeshi; Oikawa, Hiroki; Sakaue, Kazuyuki; Washio, Masakazu; Yonemura, Motoki; Yoshizawa, Toru; Tyo, J. Scott; Otani, Yukitoshi

    2015-01-01

    Vectorial vortex analysis is used to determine the polarization states of an arbitrarily polarized terahertz (0.1–1.6?THz) beam using THz achromatic axially symmetric wave (TAS) plates, which have a phase retardance of ? = 163° and are made of polytetrafluorethylene. Polarized THz beams are converted into THz vectorial vortex beams with no spatial or wavelength dispersion, and the unknown polarization states of the incident THz beams are reconstructed. The polarization determination is also demonstrated at frequencies of 0.16 and 0.36?THz. The results obtained by solving the inverse source problem agree with the values used in the experiments. This vectorial vortex analysis enables a determination of the polarization states of the incident THz beam from the THz image. The polarization states of the beams are estimated after they pass through the TAS plates. The results validate this new approach to polarization detection for intense THz sources. It could find application in such cutting edge areas of physics as nonlinear THz photonics and plasmon excitation, because TAS plates not only instantaneously elucidate the polarization of an enclosed THz beam but can also passively control THz vectorial vortex beams. PMID:25799965

  15. Impact of sudden Arctic sea-ice loss on stratospheric polar ozone recovery

    E-print Network

    Wirosoetisno, Djoko

    Impact of sudden Arctic sea-ice loss on stratospheric polar ozone recovery Article Published.G. and Ravishankara, A.R. (2009) Impact of sudden Arctic sea-ice loss on stratospheric polar ozone recovery's research outputs online #12;Impact of sudden Arctic sea-ice loss on stratospheric polar ozone recovery J. F

  16. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses

    E-print Network

    Wirosoetisno, Djoko

    The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse, C. M. (2014) The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses,KostovY,HausmannU,FerreiraD,Shepherd TG, Bitz CM. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses

  17. Optical backscatter characteristics of Arctic polar stratospheric clouds

    NASA Technical Reports Server (NTRS)

    Kent, G. S.; Schaffner, S. K.; Poole, L. R.; Mccormick, M. P.; Hunt, W. H.

    1990-01-01

    Airborne lidar measurements have been made of polar stratospheric clouds (PSCs) during the Airborne Arctic Stratospheric Expedition in January-February 1989. These show the existence of a systematic relationship between the backscatter depolarization ratio and the (aerosol + molecular)/molecular backscatter ratio. The data are consistent with a two population PSC particle model.

  18. Dynamics of polarized vortex solitons in nonlocal media with Bessel optical lattices.

    PubMed

    Zhang, Bingzhi; Chen, Zhifeng

    2015-09-21

    We investigate the formation of polarized vortex solitons in nonlocal media with Bessel optical lattices and show the various dynamics of these solitons. Particularly, the stable high-order polarized vortex solitons, which are not found in local media with Bessel optical lattices, are found in nonlocal media. It is found that the nonlocal nonlinearity plays an important role in the stability of these solitons which is similar to that of phase vortex solitons. However, we show that the dynamics of these polarized vortex solitons are quite different from the phase vortex solitons. PMID:26406632

  19. The Role of Stratospheric Polar Vortex Breakdown in Southern Hemisphere Climate Trends

    E-print Network

    Chen, Gang

    The Role of Stratospheric Polar Vortex Breakdown in Southern Hemisphere Climate Trends LANTAO SUN the delay in the final breakdown of the stratospheric polar vortex, the stratospheric final warming (SFW the ozone depletion is mimicked by a springtime polar stratospheric cooling. The responses of zonal

  20. On the Lagrangian Dynamics of Atmospheric Zonal Jets and the Permeability of the Stratospheric Polar Vortex

    E-print Network

    Olascoaga, Maria Josefina

    at the perimeter of the stratospheric polar vortex in the austral spring. 1. Introduction It is now generally stratospheric polar vortex is less effective as a meridi- onal transport barrier than its Southern Hemisphere in the stratospheric polar vor- tices derives from observations of the Antarctic ozone hole and, to a lesser extent

  1. Stratosphere-troposphere evolution during polar vortex intensification Varavut Limpasuvan,1

    E-print Network

    Limpasuvan, Varavut

    Stratosphere-troposphere evolution during polar vortex intensification Varavut Limpasuvan,1 Dennis and descending westerly anomalies over the depth of the polar stratosphere. Reduced poleward planetary wave heat (2005), Stratosphere-troposphere evolution during polar vortex intensification, J. Geophys. Res., 110, D

  2. Polar Oceanography, Arctic Sea Ice and Climate

    NASA Astrophysics Data System (ADS)

    Timmermans, Mary-Louise

    2015-03-01

    Intensive sampling from oceanographic moorings, shipboard measurements, and drifting autonomous buoy systems has brought new understanding to Arctic freshwater dynamics, ocean heat and mixing processes, circulation and eddies, and atmosphere-ice-ocean interactions. Observations indicate apparently rapid changes in the basin-scale freshwater distribution that have marked effects on Arctic stratification. Recent measurements support the idea that a strengthened stratification limits the vertical flux of deep-ocean heat. All ocean layers exhibit a rich mesoscale eddy field; eddies, with scales comparable to the Rossby Deformation Radius [O(10km)], transport water and heat over long distances and enhance ocean mixing. Measurements further reveal an active submesoscale flow field in the ocean surface layer. These upper-ocean features, having length scales of a few kilometers or less, are dynamically important in that they can impede surface-layer deepening and modify heat, salt, and momentum fluxes between the surface ocean and adjacent sea-ice cover. This talk will review highlights of recent Arctic Ocean observational studies across a range of temporal and spatial scales, and outline advances in our understanding of ocean drivers of sea ice and climate change.

  3. Study of the winter 2005 Antarctica polar vortex

    E-print Network

    Lascaux, F; Hagelin, S; Stoesz, J; 10.1051/eas/1040013

    2010-01-01

    During winter and springtime, the flow above Antarctica at high altitude (upper troposphere and stratosphere) is dominated by the presence of a vortex centered above the continent. It lasts typically from August to November. This vortex is characterized by a strong cyclonic jet centered above the polar high. In a recent study of our group (Hagelin et al., 2008) of four different sites in the Antarctic internal plateau (South Pole, Dome C, Dome A and Dome F), it was made the hypothesis that the wind speed strength in the upper atmosphere should be related to the distance of the site to the center of the Antarctic polar vortex. This high altitude wind is very important from an astronomical point of view since it might trigger the onset of the optical turbulence and strongly affect other optical turbulence parameters. What we are interested in here is to localize the position of the minimum value of the wind speed at high altitude in order to confirm the hypothesis of Hagelin et al. (2008).

  4. Venusian Polar Vortex reproduced in an Atmospheric General Circulation Model

    NASA Astrophysics Data System (ADS)

    Ando, Hiroki; Imamura, Takeshi; Takagi, Masahiro; Sugimoto, Norihiko; Kashimura, Hiroki

    The Venus atmosphere has a polar vortex rotating in the retrograde direction with a period of about three days. The vortex has a warm feature surrounded by a cold collar (e.g., Taylor et al. 1980; Piccioni et al. 2006). Although the Venusian polar vortex has been reported by many observations, its mechanism is still unknown. Elson (1982, 1989) examined the structure of the polar vortex by linear calculations. However, the background zonal wind assumed in the calculations was much stronger or weaker than those retrieved in the previous measurements (e.g., Peralta et al. 2008; Kouyama et al. 2012). Lee et al. (2010) and Yamamoto and Takahashi (2012) performed numerical simulations with general circulation models (GCMs) of the Venus atmosphere and obtained vertical structure in the polar region. However, the models included artificial forcing of Kelvin and/or Rossby waves. We have developed a new Venusian GCM by modifying the Atmospheric GCM For the Earth Simulator (Sugimoto et al. 2012; 2013). The basic equations of the GCM are primitive ones in the sigma coordinate on a sphere without topography. The model resolution is T42 (i.e., about 2.8 deg x 2.8 deg grids) and L60 (Deltaz is about 2 km). Rayleigh friction (sponge layer) in the upper layer (>80 km) is applied to prevent the reflection of waves, whose effect increases gradually with height. In the model, the atmosphere is dry and forced by the solar heating and Newtonian cooling. The vertical profile of the solar heating is based on Crisp (1986), and zonally averaged distribution is used. In addition diurnal component of the solar heating, which excites the diurnal and semi-diurnal tides, is also included. Newtonian cooling relaxes the temperature to the zonally uniform basic temperature which has a virtual static stability of Venus with almost neutral layers, and its coefficient is based on Crisp (1986). To prevent numerical instability, the biharmonic hyper-diffusion is included with 0.8 days of e-folding time for the truncation wavenumber. The coefficient of the vertical eddy diffusion is 0.15 m (2) s (-1) . A fast zonal wind in a solid-body rotation and the temperature field that balances with the zonal wind (gradient wind balance) is given as the initial state. Time integrations are performed until the solution achieves a statistically steady state. In this study we analyzed the data of 300 days of the last from getting to the quasi-steady state. The temporal and zonal mean wind and temperature fields are almost consistent with those obtained in previous studies (e.g., Kouyama et al. 2012; Tellmann et al. 2009). Barotropic or baroclinic instability occurs at the polar region, and zonal wavenumber one component is the most dominant in the polar vortex, followed by wavenumber two. It rotates the pole with the period of 4-5 days. These features are almost consistent with recent measurements (e.g. Lopez et al. 2013). We also calculated the potential vorticity distribution and found that it sometimes shows the filament structure, which is similar to the cloud morphology observed in recent imaging measurements (e.g. Piccioni et al. 2006). The vertical structure of each zonal wavenumber component has the common feature that the phase stands upright within the polar vortex and seems to shift at the top of the neutral stable layer. In this presentation, we will also compare the vertical structure seen in our calculation with that examined by radio occultation measurements in Venus Express mission.

  5. A minor sudden stratospheric warming with a major impact: Transport and polar processing in the 2014/2015 Arctic winter

    NASA Astrophysics Data System (ADS)

    Manney, Gloria L.; Lawrence, Zachary D.; Santee, Michelle L.; Read, William G.; Livesey, Nathaniel J.; Lambert, Alyn; Froidevaux, Lucien; Pumphrey, Hugh C.; Schwartz, Michael J.

    2015-09-01

    Stratospheric transport and polar processing during the 2014/2015 Arctic winter were strongly influenced by a minor sudden stratospheric warming (SSW) in early January. Disturbances to temperatures and trace gases in the middle and upper stratosphere were similar in character to those associated with major SSWs: The stratopause dropped, and vertical temperature gradients weakened, followed by renewed descent of mesospheric air. The lower stratospheric polar vortex was barely disrupted and remained unusually strong throughout the winter. The SSW did, however, cause lower stratospheric temperatures to rise well above chlorine activation thresholds; trace gas abundances from the Aura Microwave Limb Sounder (MLS) were consequently exceptional. The degree of chlorine activation in January was the smallest, and lower stratospheric ozone values in February were the highest, in the 11 year MLS record. The major role played by a minor SSW highlights the Arctic stratosphere's sensitivity to a spectrum of dynamical variability.

  6. Pipeline under the arctic ice: the Polar Gas Project

    SciTech Connect

    Kaustinen, O.M.

    1982-06-01

    The Polar Gas Project was established in 1972 to determine the best means of moving frontier natural gas from Canada's high arctic to southern markets. Pipeline was found to be most feasible. Several pipeline routings from two major supply areas--the MacKenzie Delta/Beaufort Sea region, and the Sverdrup Basin of the Arctic Islands--have been considered. Field programs to determine the type and ice content of soils along the route have been undertaken. The most challenging engineering aspect will be two marine crossings in arctic waters at either end of Victoria Island, at Dolphin and Union Strait, and at McClure's strait. The ''Ice Hole Bottom Pull'' technique has been recommended, and is illustrated in detail. The planned pipeline demonstration would significantly enhance the current state-of-the-art for deepwater pipelining worldwide.

  7. Optimally coherent sets in geophysical flows: A new approach to delimiting the stratospheric polar vortex

    E-print Network

    Santitissadeekorn, Naratip; Monahan, Adam

    2010-01-01

    The "edge" of the Antarctic polar vortex is known to behave as a barrier to the meridional (poleward) transport of ozone during the austral winter. This chemical isolation of the polar vortex from the middle and low latitudes produces an ozone minimum in the vortex region, intensifying the ozone hole relative to that which would be produced by photochemical processes alone. Observational determination of the vortex edge remains an active field of research. In this letter, we obtain objective estimates of the structure of the polar vortex by introducing a new technique based on transfer operators that aims to find regions with minimal external transport. Applying this new technique to European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-40 three-dimensional velocity data we produce an improved three-dimensional estimate of the vortex location in the upper stratosphere where the vortex is most pronounced. This novel computational approach has wide potential application in detecting and analysing mixin...

  8. Airborne lidar observations in the wintertime Arctic stratosphere: Polar stratospheric clouds

    SciTech Connect

    Browell, E.V.; Ismail, S.; Carter, A.F.; Higdon, N.S. ); Butler, C.F.; Robinette, P.A. ); Toon, O.B. ); Schoeberl, M.R. ); Tuck, A.F. )

    1990-03-01

    Polar stratospheric cloud (PSC) distributions in the wintertime Arctic stratosphere and their optical characteristics were measured with a multi-wavelength airborne lidar system as part of the 1989 Airborne Arctic Stratospheric Expedition. PSCs were observed on 10 flights between January 6 and February 2, 1989, into the polar vortex. The PSCs were found in the 14-27 km altitude range in regions where the temperatures were {le}195 K. Two types of aerosols with different optical characteristics (Types 1a and 1b) were observed in PSCs thought to be composed of nitric acid trihydrate. Type 1a PSCs typically exhibited low scattering ratios (1.2-1.5) and high aerosol depolarizations (30-50%) at 603 nm, while Type 1b PSCs had higher scattering ratios (3-8) and lower aerosol depolarizations (0.5-2.5%). Water ice PSCs (Type 2) were observed to have high scattering ratios (>10) and high aerosol depolarizations (>10%) at temperatures {le}190 K.

  9. Chlorine chemistry on polar stratospheric cloud particles in the Arctic winter

    NASA Technical Reports Server (NTRS)

    Webster, C. R.; May, R. D.; Toohey, D. W.; Avallone, L. M.; Anderson, J. G.; Newman, P.; Lait, L.; Schoeberl, M. R.; Elkins, J. W.; Chan, K. R.

    1993-01-01

    Simultaneous in situ measurements of hydrochloric acid (HCl) and chlorine monoxide (ClO) in the Arctic winter vortex showed large HCl losses of up to 1 ppbv, which were correlated with high ClO levels of up to 1.4 ppbv. Air parcel trajectory analysis identified that this conversion of inorganic chlorine occurred at air temperatures of less than 196 -/+ 4 kelvin. High ClO was always accompanied by loss of HCl mixing ratios equal to 1/2(ClO+ 2Cl2O2). These data indicate that the heterogeneous reaction HCl + ClONO2 - Cl2 + HNO3 on particles of polar stratospheric clouds establishes the chlorine partitioning, which, contrary to earlier notions, begins with an excess of ClONO2, not HCl.

  10. Chlorine chemistry on polar stratospheric cloud particles in the Arctic winter

    SciTech Connect

    Webster, C.R.; May, R.D. ); Toohey, D.W. ); Avallone, L.M.; Anderson, J.G. ); Newman, P.; Lait, L.; Schoeberl, M.R. ); Elkins, J.W. ); Chan, K.R. )

    1993-08-27

    Simultaneous in situ measurements of hydrochloric acid (HCl) and chlorine monoxide (ClO) in the Arctic winter vortex showed large HCl losses, of up to 1 part per billion by volume (ppbv), which were correlated with high ClO levels of up to 1.4 ppbv. Air parcel trajectory analysis identified that this conversion of inorganic chlorine occurred at air temperatures of less than 196 [plus minus]4 kelvin. High ClO was always accompanied by loss of HCl mixing ratios equal to 1/2(ClO + 2Cl[sub 2]O[sub 2]). These data indicate that the heterogeneous reaction HCl + ClONO[sub 2] [yields] Cl[sub 2] + HNO[sub 3] on particles of polar stratospheric clouds establishes the chlorine partitioning, which, contrary to earlier notions, begins with an excess of ClONO[sub 2], not HCl.

  11. Chlorine chemistry on polar stratospheric cloud particles in the arctic winter.

    PubMed

    Webster, C R; May, R D; Toohey, D W; Avallone, L M; Anderson, J G; Newman, P; Lait, L; Schoeberl, M R; Elkins, J W; Chan, K R

    1993-08-27

    Simultaneous in situ measurements of hydrochloric acid (HCl) and chlorine monoxide (ClO) in the Arctic winter vortex showed large HCl losses, of up to 1 part per billion by volume (ppbv), which were correlated with high ClO levels of up to 1.4 ppbv. Air parcel trajectory analysis identified that this conversion of inorganic chlorine occurred at air temperatures of less than 196 +/- 4 kelvin. High ClO was always accompanied by loss of HCI mixing ratios equal to (1/2)(ClO + 2Cl(2)O(2)). These data indicate that the heterogeneous reaction HCl + ClONO(2) --> Cl(2) + HNO(3) on particles of polar stratospheric clouds establishes the chlorine partitioning, which, contrary to earlier notions, begins with an excess of ClONO(2), not HCl. PMID:17790344

  12. Hyperbolic lines and the stratospheric polar vortex Tieh-Yong Koha)

    E-print Network

    Legras, Bernard

    Hyperbolic lines and the stratospheric polar vortex Tieh-Yong Koha) and Bernard Legrasb that it is too weak to detect elliptic coherent structures ECS in the stratosphere, of which the polar vortex. These mathematically rigorous conditions are applied to the winter stratospheric circulation of the southern hemisphere

  13. On the Role of the Arctic Ocean in Polar Amplification

    NASA Astrophysics Data System (ADS)

    Maslowski, Wieslaw; Osinski, Robert; Clement Kinney, Jaclyn

    2014-05-01

    Understanding oceanic effects on climate in the Arctic region requires knowledge of the mean circulation and its seasonal to decadal variability in the region. We synthesize results from a hierarchy of climate models together with available observations in the pan-Arctic region to better understand potential oceanic contributions to polar amplification. In particular, results from a version of the Regional Arctic System Model (RASM) forced with multi-decadal reanalysis data are analyzed with the main focus on the annual cycle and interannual to decadal variability of the upper ocean heat content in relation to the decline of the Arctic sea ice cover and warming climate. The motivation for this study is the increase of heat accumulation in the upper ocean, which has been observed and simulated by some model since the late 1990s. We investigate the circulation patterns and their seasonal to decadal variability controlling inflow of volume and properties into the Arctic Ocean. In addition, we examine critical processes governing the outflow of warm water, including coastal runoff, from the shelves into basin, for their impact on retreat and thinning of sea ice cover. Finally, the transport due to the boundary current along the slope and eddies in the basin are considered for their redistribution of heat within the upper ocean and contribution to the overall state of sea ice cover. The main goal of this study is to advance a system-level understanding of critical processes and feedbacks in the Arctic and their links with the Earth System. The secondary, yet an equally important objective, is to identify important areas from which to obtain new or additional observations to better understand some of these processes and to help constrain models.

  14. Vortex-wide chlorine activation by a localized PSC event in the Arctic winter of 2009/10

    NASA Astrophysics Data System (ADS)

    Wegner, Tobias; Poole, Lamont; Tritscher, Ines; Grooss, Jens-Uwe; Nakajima, Hideaki; Pitts, Michael

    2015-04-01

    During the polar night chlorine reservoir species react heterogeneously to photo-labile chlorine compounds which drive ozone-loss cycles, eventually leading to the ozone-hole. We investigate this process for the Arctic winter 2009/10 using satellite data and model simulations. CALIPSO observations indicate localized Ppolar Stratospheric Cloud (PSC) occurrences east of Greenland beginning of January 2010 with MLS observations indicating a decrease in HCl mixing ratios co-located and downstream of these PSCs. This localized PSC event has a bigger extent than mountain-wave PSCs but still only covers a fraction of the entire vortex. Trajectory calculations confirm that low HCl mixing ratios correspond to air that has passed through PSCs. Following trajectories started in PCSs show that chlorine is activated in these cluods nad subsequently this air with low HCl mixing ratios is adveted throughout the vortex. Regions with high HCl mixing ratios correspond to air masses which haven't been exposed to PSC. After five days all vortex air has passed through the PSC which shows that such localized PSCs can activate the entire vortex within a week. Chlorine activation does not occur homogeneously throughout the vortex but rather in a localized area with air constantly flowing through. This area corresponds to the area where CALIPSO observed PSCs. Comparing the area where activation occurs with indicators of chlorine activation such as TNAT and TACl we find that these indicators overestimate the area where chlorine activation is expected to occur. In addition, heterogeneous chemistry is modeled along the trajectories passing through PSCs. Trajectory calculations are initialized upstream of PSCs with observations from MLS, tracer-tracer correlations and non-observed species from a CLaMS simulation. The CALIPSO backscatter product is used to estimate surface area density. Our calculations of HCl agree well with MLS observations downstream of PSCs. They also indicate that ClONO2 is the limiting factor in chlorine activation. Overall, we find that heterogeneous chemistry can explain observations of HCl by MLS and that chlorine activation is limited to the area where PSCs are present.

  15. Nanoscale switch for vortex polarization mediated by Bloch core formation in magnetic hybrid systems

    PubMed Central

    Wohlhüter, Phillip; Bryan, Matthew Thomas; Warnicke, Peter; Gliga, Sebastian; Stevenson, Stephanie Elizabeth; Heldt, Georg; Saharan, Lalita; Suszka, Anna Kinga; Moutafis, Christoforos; Chopdekar, Rajesh Vilas; Raabe, Jörg; Thomson, Thomas; Hrkac, Gino; Heyderman, Laura Jane

    2015-01-01

    Vortices are fundamental magnetic topological structures characterized by a curling magnetization around a highly stable nanometric core. The control of the polarization of this core and its gyration is key to the utilization of vortices in technological applications. So far polarization control has been achieved in single-material structures using magnetic fields, spin-polarized currents or spin waves. Here we demonstrate local control of the vortex core orientation in hybrid structures where the vortex in an in-plane Permalloy film coexists with out-of-plane maze domains in a Co/Pd multilayer. The vortex core reverses its polarization on crossing a maze domain boundary. This reversal is mediated by a pair of magnetic singularities, known as Bloch points, and leads to the transient formation of a three-dimensional magnetization structure: a Bloch core. The interaction between vortex and domain wall thus acts as a nanoscale switch for the vortex core polarization. PMID:26238042

  16. Arctic stratospheric winter warming forced by observed SSTs Yongyun Hu1

    E-print Network

    Hu, Yongyun

    warming trends in the Arctic lower stratosphere. It also shows a weakened Arctic polar vortex the negative polarity of an annular-like mode. Further analyses indicate that the Arctic stratospheric warming stratospheric clouds, which slows down the rates of heterogeneous chemical reactions and thus benefits

  17. A climatology of stratopause temperature and height in the polar vortex and anticyclones

    NASA Astrophysics Data System (ADS)

    France, J. A.; Harvey, V. L.; Randall, C. E.; Hitchman, M. H.; Schwartz, M. J.

    2012-03-01

    A global climatology of stratopause temperature and height is shown using 7 years of Microwave Limb Sounder satellite data, from 2004 to 2011. Stratopause temperature and height is interpreted in the context of the polar vortices and anticyclones defined by the Goddard Earth Observing System meteorological analyses. Multiyear, monthly mean geographic patterns in stratopause temperature and height are shown to depend on the location of the polar vortices and anticyclones. The anomalous winters of 2005/2006 and 2008/2009 are considered separately in this analysis. In the anomalous years, we show that the elevated stratopause in February is confined to the vortex core. This is the first study to show that the stratopause is, on average, 20 K colder and 5-10 km lower in the Aleutian anticyclone than in ambient air during the Arctic winter. During September in the Antarctic the stratopause is, on average, 10 K colder inside anticyclones south of Australia. The regional temperature and height anomalies, which are due to vertical ageostrophic motion associated with baroclinic instability, are shown to be climatological features. The mean structure of the temperature and height anomalies is consistent with moderate baroclinic growth below the stratopause and decay above. This work furthers current understanding of the geography of the stratopause by emphasizing the role of synoptic baroclinic instability, whereby anticyclones establish zonally asymmetric climatological patterns in stratopause temperature and height. This work highlights the need to consider zonal asymmetries when calculating upper stratospheric temperature trends.

  18. The evolution of AAOE observed constituents with the polar vortex

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.; Lait, Leslie R.; Newman, P. A.; Martin, R.; Loewenstein, M.; Podolske, J. R.; Anderson, J.; Proffitt, M. H.

    1988-01-01

    One of the difficulties in determining constituent trends from the ER-2 flight data is the large amount of day to day variability generated by the motion of the polar vortex. To reduce this variability, the observations have been transformed into the conservative (Lagrangian) reference frames consisting of the coordinate pairs, potential temperature (PT) and potential vorticity (PV), or PT and N2O. The requirement of only two independent coordinates rests on the assumption that constituent distributions and their chemical processes are nearly zonal in that coordinate system. Flight data is used everywhere for these transformation except for potential vorticity. Potential vorticity is determined from level flight segments, and NMC PV values during flight dives and takeoffs are combined with flight data in a smooth fashion.

  19. Visualization of stratospheric ozone depletion and the polar vortex

    SciTech Connect

    Treinish, L.A.

    1995-01-01

    Direct analysis of spacecraft observations of stratospheric ozone yields information about the morphology of annual austral depletion. Visual correlation of ozone with other atmospheric data illustrates the diurnal dynamics of the polar vortex and contributions from the upper troposphere, including the formation and breakup of the depletion region each spring. These data require care in their presentation to minimize the introduction of visualization artifacts that are erroneously interpreted as data features. Non geographically registered data of differing mesh structures can be visually correlated via cartographic warping of base geometries without interpolation. Because this approach is independent of the realization technique, it provides a framework for experimenting with many visualization strategies. This methodology preserves the fidelity of the original data sets in a coordinate system suitable for three-dimensional, dynamic examination of atmospheric phenomena.

  20. Tracer-Based Determination of Vortex Descent in the 1999-2000 Arctic Winter

    NASA Technical Reports Server (NTRS)

    Greenblatt, Jeffery B.; Jost, Hans-Juerg; Loewenstein, Max; Podolske, James R.; Hurst, Dale F.; Elkins, James W.; Schauffler, Sue M.; Atlas, Elliot L.; Herman, Robert L.; Webster, Christopher R.

    2001-01-01

    A detailed analysis of available in situ and remotely sensed N2O and CH4 data measured in the 1999-2000 winter Arctic vortex has been performed in order to quantify the temporal evolution of vortex descent. Differences in potential temperature (theta) among balloon and aircraft vertical profiles (an average of 19-23 K on a given N2O or CH4 isopleth) indicated significant vortex inhomogeneity in late fall as compared with late winter profiles. A composite fall vortex profile was constructed for November 26, 1999, whose error bars encompassed the observed variability. High-latitude, extravortex profiles measured in different years and seasons revealed substantial variability in N2O and CH4 on theta surfaces, but all were clearly distinguishable from the first vortex profiles measured in late fall 1999. From these extravortex-vortex differences, we inferred descent prior to November 26: 397+/-15 K (1sigma) at 30 ppbv N2O and 640 ppbv CH4, and 28+/-13 K above 200 ppbv N2O and 1280 ppbv CH4. Changes in theta were determined on five N2O and CH4 isopleths from November 26 through March 12, and descent rates were calculated on each N2O isopleth for several time intervals. The maximum descent rates were seen between November 26 and January 27: 0.82+/-0.20 K/day averaged over 50-250 ppbv N2O. By late winter (February 26-March 12), the average rate had decreased to 0.10+/-0.25 K/day. Descent rates also decreased with increasing N2O; the winter average (November 26-March 5) descent rate varied from 0.75+/-0.10 K/day at 50 ppbv to 0.40+/-0.11 K/day at 250 ppbv. Comparison of these results with observations and models of descent in prior years showed very good overall agreement. Two models of the 1999-2000 vortex descent, SLIMCAT and REPROBUS, despite theta offsets with respect to observed profiles of up to 20 K on most tracer isopleths, produced descent rates that agreed very favorably with the inferred rates from observation.

  1. Lidar measurements of polar stratospheric clouds during the 1989 airborne Arctic stratospheric expedition

    NASA Technical Reports Server (NTRS)

    Ismail, Syed; Browell, Edward V.

    1991-01-01

    The Airborne Arctic Stratospheric Expedition (AASE) was conducted during January to February 1989 from the Sola Air Station, Norway. As part of this expedition, the NASA Langley Research Center's multiwavelength airborne lidar system was flown on the NASA Ames Research Center's DC-8 aircraft to measure ozone (O3) and aerosol profiles in the region of the polar vortex. The lidar system simultaneously transmitted laser beams at 1064, 603, 311, and 301.5 nm to measure atmospheric scattering, polarization and O3 profiles. Long range flights were made between Stavanger, Norway, and the North Pole, and between 40 deg W and 20 deg E meridians. Eleven flights were made, each flight lasting an average of 10 hours covering about 8000 km. Atmospheric scattering ratios, aerosol polarizations, and aerosol scattering ratio wavelength dependences were derived from the lidar measurements to altitudes above 27 km. The details of the aerosol scattering properties of lidar observations in the IR, VIS, and UV regions are presented along with correlations with the national meteorological Center's temperature profiles.

  2. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to

    E-print Network

    The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse forcing asymmetric Arctic and Antarctic responses to The ocean's role in polar climate change: References of the risks of climate change and the challenges of limiting human influence on the environment

  3. Variability of the polar stratospheric vortex and its impact on surface climate patterns

    E-print Network

    Sheshadri, Aditi

    2015-01-01

    This thesis investigates various aspects of the variability of the stratospheric polar vortex and the effect of this variability on tropospheric weather and climate patterns on various timescales. In the first part of this ...

  4. OMAE 1996 -- Proceedings of the 15. international conference on offshore mechanics and arctic engineering. Volume 4: Arctic/polar technology

    SciTech Connect

    Nixon, W.A.; Sodhi, D.S.; Kennedy, K.P.; Bugno, W.

    1996-12-01

    Volume 4 contains papers on the following topics: arctic/polar technology and development; ice properties; ice engineering; applied ice mechanics; ice-structure interaction; arctic structures and operations; frozen soil properties; and Russian Arctic development. In addition to the regular topics covered in OMAE conferences, there has been a special workshop as part of this year`s conference. In keeping with issues of current interest, there is a workshop on development of oil resources in the Russian Arctic. Over two days, papers dealing with development of oil and gas resources in the Russian Arctic are presented. Volume 4 contains papers from this workshop. Some of the papers have been processed separately for inclusion on the data base.

  5. Aircraft deployment, and airborne arctic stratospheric expedition

    NASA Technical Reports Server (NTRS)

    Condon, Estelle; Tuck, Adrian; Hipskind, Steve; Toon, Brian; Wegener, Steve

    1990-01-01

    The Airborne Arctic Stratospheric Expedition had two primary objectives: to study the production and loss mechanisms of ozone in the north polar stratosphere and to study the effect on ozone distribution of the Arctic Polar Vortex and of the cold temperatures associated with the formation of Polar Stratospheric Clouds. Two specially instrumented NASA aircraft were flown over the Arctic region. Each aircraft flew to acquire data on the meteorological, chemical and cloud physical phenomena that occur in the polar stratosphere during winter. The chemical processes which occur in the polar stratosphere during winter were also observed and studied. The data acquired are being analyzed.

  6. Dynamics of the stratospheric polar vortex and its relation to springtime ozone depletions

    SciTech Connect

    Schoeberl, M.R. ); Hartmann, D.L. )

    1991-01-01

    Dramatic springtime depletions of ozone in polar regions require that polar stratospheric air has a high degree of dynamical isolation and extremely cold temperatures necessary for the formation of polar stratospheric clouds. Both of these conditions are produced within the stratospheric winter polar vortex. Recent aircraft missions have provided new information about the structure of polar vortices during winter and their relation to polar ozone depletions. The aircraft data show that gradients of potential vorticity and the concentration of conservative trace species are large at the transition from mid-latitude to polar air. The presence of such sharp gradients at the boundary of polar air implies that the inward mixing of heat and constituents is strongly inhibited and that the perturbed polar stratospheric chemistry associated with the ozone hole is isolated from the rest of the stratosphere until the vortex breaks up in late spring. The overall size of the polar vortex thus limits the maximum areal coverage of the annual polar ozone depletions. Because it appears that this limit has not been reached for the Antarctic depletions, the possibility of future increases in the size of the Antarctic ozone hole is left open. In the Northern Hemisphere, the smaller vortex and the more restricted region of cold temperatures suggest that this region has a smaller theoretical maximum for column ozone depletion, about 40 percent of the currently observed change in the Antarctic ozone column in spring. 5 figs., 43 refs.

  7. Generation of cylindrically polarized vector vortex beams with digital micromirror device

    SciTech Connect

    Gong, Lei; Liu, Weiwei; Wang, Meng; Zhong, Mincheng; Wang, Ziqiang; Li, Yinmei; Ren, Yuxuan

    2014-11-14

    We propose a novel technique to directly transform a linearly polarized Gaussian beam into vector-vortex beams with various spatial patterns. Full high-quality control of amplitude and phase is implemented via a Digital Micro-mirror Device (DMD) binary holography for generating Laguerre-Gaussian, Bessel-Gaussian, and helical Mathieu–Gaussian modes, while a radial polarization converter (S-waveplate) is employed to effectively convert the optical vortices into cylindrically polarized vortex beams. Additionally, the generated vector-vortex beams maintain their polarization symmetry after arbitrary polarization manipulation. Due to the high frame rates of DMD, rapid switching among a series of vector modes carrying different orbital angular momenta paves the way for optical microscopy, trapping, and communication.

  8. Optical backscatter characteristics of Arctic polar stratospheric clouds

    SciTech Connect

    Kent, G.S.; Schaffner, S.K. ); Poole, L.R.; McCormick, M.P. ); Hunt, W.H. ); Osborn, M.T. )

    1990-03-01

    Airborne lidar measurements have been made of polar stratospheric clouds (PSCs) during the Airborne Arctic Stratospheric Expedition in January-February 1989. These show the existence of a systematic relationship between the backscatter depolarization ratio, {delta}, and the (aerosol + molecular)/molecular backscatter ratio, R. The data are consistent with a two population PSC particle model. The first population consists of particles with low values for {delta} ({le} 0.02) and low to intermediate values for R ({le} 6). The second population is characterized by higher values for {delta} (up to 0.60) and R (up to 40 or greater). The relationship between {delta} and R, observed within a limited range of altitudes and latitudes, corresponds to a mixture of the two populations with variable concentrations but constant optical properties.

  9. Optimally coherent sets in geophysical flows: A transfer-operator approach to delimiting the stratospheric polar vortex

    E-print Network

    Froyland, Gary

    the stratospheric polar vortex Naratip Santitissadeekorn,1 Gary Froyland,1 and Adam Monahan2 1 School of Mathematics focuses on the upper stratosphere where the polar vortex is best developed. It is common meteorological; revised manuscript received 8 August 2010; published 12 November 2010 The "edge" of the Antarctic polar

  10. The Sensitivity of Arctic Ozone Loss to Polar Stratospheric Cloud Volume and Chlorine and Bromine Loading in a Chemistry and Transport Model

    NASA Technical Reports Server (NTRS)

    Douglass, A. R.; Stolarski, R. S.; Strahan, S. E.; Polansky, B. C.

    2006-01-01

    The sensitivity of Arctic ozone loss to polar stratospheric cloud volume (V(sub PSC)) and chlorine and bromine loading is explored using chemistry and transport models (CTMs). A simulation using multi-decadal output from a general circulation model (GCM) in the Goddard Space Flight Center (GSFC) CTM complements one recycling a single year s GCM output in the Global Modeling Initiative (GMI) CTM. Winter polar ozone loss in the GSFC CTM depends on equivalent effective stratospheric chlorine (EESC) and polar vortex characteristics (temperatures, descent, isolation, polar stratospheric cloud amount). Polar ozone loss in the GMI CTM depends only on changes in EESC as the dynamics repeat annually. The GSFC CTM simulation reproduces a linear relationship between ozone loss and Vpsc derived from observations for 1992 - 2003 which holds for EESC within approx.85% of its maximum (approx.1990 - 2020). The GMI simulation shows that ozone loss varies linearly with EESC for constant, high V(sub PSC).

  11. Optimally coherent sets in geophysical flows: A new approach to delimiting the stratospheric polar vortex

    E-print Network

    Naratip Santitissadeekorn; Gary Froyland; Adam Monahan

    2010-04-20

    The "edge" of the Antarctic polar vortex is known to behave as a barrier to the meridional (poleward) transport of ozone during the austral winter. This chemical isolation of the polar vortex from the middle and low latitudes produces an ozone minimum in the vortex region, intensifying the ozone hole relative to that which would be produced by photochemical processes alone. Observational determination of the vortex edge remains an active field of research. In this letter, we obtain objective estimates of the structure of the polar vortex by introducing a new technique based on transfer operators that aims to find regions with minimal external transport. Applying this new technique to European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-40 three-dimensional velocity data we produce an improved three-dimensional estimate of the vortex location in the upper stratosphere where the vortex is most pronounced. This novel computational approach has wide potential application in detecting and analysing mixing structures in a variety of atmospheric, oceanographic, and general fluid dynamical settings.

  12. In-situ measurements of changes in stratospheric aerosol and the N[sub 2]O-aerosol relationship inside and outside of the polar vortex

    SciTech Connect

    Borrmann, S.; Dye, J.E.; Baumgardner, D.; Barr, K.S. ); Wilson, J.C.; Jonsson, H.H.; Brock, C.A. ); Loewenstein, M.; Podolske, J.R.; Ferry, G.V. )

    1993-11-19

    Two optical particle counters on the ER-2, together covering a particle size diameter range from 0.1 [mu]m to 23 [mu]m, were used to measure the aerosol bulk quantities integral number, aerosol surface and volume, as well as detailed size distributions inside and outside of the polar vortex in the lower stratosphere. While AASE I (Arctic Airborne Stratospheric Expedition), (Dec. 88-Feb. 89) was conducted in a period of relative volcanic quiescence, enhancements in aerosol number, surface and volume of factors around 10, 25 and 100 were observed during AASE II (Aug. 91-Mar. 92) due to the eruption of Mt. Pinatubo. The changes in these bulk quantities as well as in the size distributions measured both outside and inside the polar vortex are presented and compared with those obtained in polar stratospheric cloud events (AASE I). Except for a shift towards larger aerosol mixing ratios the general shape of correlograms between the measured N[sub 2]O and particle mixing ratios remain similar before and after the eruption. Similar correlograms are used to interpret data from vertical profiles inside and outside of the polar vortex. 13 refs., 5 figs., 1 tab.

  13. In-situ measurements of changes in stratospheric aerosol and the N2O-aerosol relationship inside and outside of the polar vortex

    NASA Technical Reports Server (NTRS)

    Borrmann, S.; Dye, J. E.; Baumgardner, D.; Wilson, J. C.; Jonsson, H. H.; Brock, C. A.; Loewenstein, M.; Podolske, J. R.; Ferry, G. V.; Barr, K. S.

    1993-01-01

    Two optical particle counters on the ER-2, together covering a particle size diameter range from 0.1 microns to 23 microns, were used to measure the aerosol bulk quantities integral number, aerosol surface and volume, as well as detailed size distributions inside and outside of the polar vortex in the lower stratosphere. While AAES I (Arctic Airborne Stratospheric Expedition, (Dec. 88 - Feb. 89) was conducted in a period of relative volcanic quiescence, enhancements in aerosol number, surface and volume of factors around 10, 25 and 100 were observed during AASE 2 (Aug. 91 - Mar. 92) due to the eruption of Mt. Pinatubo. The changes in these bulk quantities as well as in the size distributions measured both outside and inside the polar vortex are presented and compared with those obtained in polar stratospheric cloud events (AASE I). Except for a shift towards larger aerosol mixing ratios the general shape of correlograms between the measured N2O and particle mixing ratios remain similar before and after the eruption. Similar correlograms are used to interpret data from vertical profiles inside and outside of the polar vortex.

  14. In-Situ Measurements of Changes in Stratospheric Aerosol and the N2O - Aerosol Relationship inside and outside of the Polar Vortex

    NASA Technical Reports Server (NTRS)

    Borrmann, S.; Dye, J. E.; Baumgardner, D.; Wilson, J. C.; Jonsson, H. H.; Brock, C. A.; Loewenstein, M.; Podolske, J. R.; Ferry, G. V.; Barr, K. S.

    1993-01-01

    Two optical particle counters on the ER-2, together covering a particle size diameter range from 0.1 micrometers to 23 micrometers, were used to measure the aerosol bulk quantities integral number, aerosol surface and volume, as well as detailed size distributions inside and outside of the polar vortex in the lower stratosphere. While AASE I (Arctic Airborne Stratospheric Expedition, (Dec. 1988 - Feb. 1989) was conducted in a period of relative volcanic quiescence, enhancements in aerosol number, surface and volume of factors around 10, 25 and 100 were observed during AASE II (Aug. 1991 - Mar. 1992) due to the eruption of Mt. Pinatubo. The changes in these bulk quantities as well as in the size distributions measured both outside and inside the the polar vortex are presented and compared with those obtained in polar stratospheric cloud events (AASE I). Except for a shift towards larger aerosol mixing ratios the general shape of correlograms between the measured N2O and particle mixing ratios remain similar before and after the eruption. Similar correlograms are used to interpret data from vertical profiles inside and outside of the polar vortex.

  15. Large-scale isentropic mixing properties of the Antarctic polar vortex from analyzed winds

    NASA Technical Reports Server (NTRS)

    Bowman, Kenneth P.

    1993-01-01

    Winds derived from analyzed geopotential height fields are used to study quasi-horizontal mixing by the large-scale flow in the lower stratosphere during austral spring. This is the period when the Antarctic ozone hole appears and disappears. Trajectories are computed for large ensembles of particles initially inside and outside the main polar vortex. Mixing and transport are diagnosed through estimates of finite time Lyapunov exponents and Lagrangian dispersion statistics of the tracer trajectories. At 450 K and above prior to the vortex breakdown: Lyapunov exponents are a factor of 2 smaller inside the vortex than outside; diffusion coefficients are an order of magnitude smaller inside than outside the vortex; and the trajectories reveal little exchange of air across the vortex boundary. At lower levels (425 and 400 K) mixing is greater, and there is substantial exchange of air across the vortex boundary. In some years there are large wave events that expel small amounts of vortex air into the mid-latitudes. At the end of the spring season during the vortex breakdown there is rapid mixing of air across the vortex boundary, which is evident in the mixing diagnostics and the tracer trajectories.

  16. Excitation of Transient Rossby Waves on the Stratospheric Polar Vortex and the Barotropic Sudden Warming

    E-print Network

    Cambridge, University of

    Excitation of Transient Rossby Waves on the Stratospheric Polar Vortex and the Barotropic Sudden, in final form 9 March 2005) ABSTRACT The excitation of Rossby waves on the edge of the stratospheric polar of the horizontal scale of the forcing to the Rossby radius. Under typical stratospheric conditions the barotropic

  17. The evolution of ozone observed by UARS MLS in the 1992 late winter southern polar vortex

    SciTech Connect

    Manney, G.L.; Froidevaux, L.; Waters, J.W.; Elson, L.S.; Fishbein, E.F.; Zurek, R.W. ); Harwood, R.S.; Lahoz, W.A. )

    1993-06-18

    This paper presents initial data analysis of ozone distributions in the southern polar vortex region during the winter of 1992. The data comes from the microwave limb sounder on the upper atmosphere research satellite. The data provides never before available coverage of the polar stratosphere, and reveals the development of an ozone hole from column ozone data, changes in ozone mixing ratios in the lower stratosphere consistent with ozone destruction processes in the stratosphere, and evidence to support the transport of ozone toward the pole by tidal wave activity in the stratosphere. The ozone measurements are compared with the development of the polar vortex derived from national meteorological center data.

  18. Impact of sudden Arctic sea-ice loss on stratospheric polar ozone J. F. Scinocca,1

    E-print Network

    Impact of sudden Arctic sea-ice loss on stratospheric polar ozone recovery J. F. Scinocca,1 M. C meridional overturning circulation. The stratospheric dynamical response leads to a 10 DU reduction in polar on stratospheric polar ozone recovery, Geophys. Res. Lett., 36, L24701, doi:10.1029/2009GL041239. 1. Introduction

  19. Arctic region Antarctica What are the differences between the two polar regions?

    E-print Network

    difference in the ice cover? ESA/AOES Medialab #12;Picture: Don Perovich Charismatic megafauna Polar bears: http://www.windows.ucar.edu/tourlink=earthpolararctic_marine_life.jpg In which season are polar bearsArctic region Antarctica What are the differences between the two polar regions? What is the main

  20. Anthropogenic Impacts on Polar Bear Biology and the Arctic Ecosystem. 

    E-print Network

    Jordan, John E.

    2013-12-16

    Despite its relative distance from most populated regions of the world, the Arctic has been significantly impacted by anthropogenic contamination and climate change. The entire Arctic ecosystem has been affected, with ...

  1. The dynamics of the stratospheric polar vortex and its relation to springtime ozone depletions

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.; Hartmann, Dennis L.

    1991-01-01

    Recent aircraft observations have determined the structure of polar vortices during winter and their relationship to polar ozone depletions, based on high dynamical isolation and the extremely low temperatures required for stratospheric cloud formation. The aircraft data reveal large gradients of potential vorticity and concentrations of conservative trace species at the transition from high-latitude to polar air, implying that the inward mixing of heat and constituents is strongly inhibited, and that the perturbed polar stratospheric chemistry associated with the ozone hole is isolated from the rest of the stratosphere until the vortex breaks up in late spring. It is therefore the overall polar vortex which limits the annual polar ozone depletions' maximum area-coverage.

  2. Structured caustic vector vortex optical field: manipulating optical angular momentum flux and polarization rotation

    PubMed Central

    Chen, Rui-Pin; Chen, Zhaozhong; Chew, Khian-Hooi; Li, Pei-Gang; Yu, Zhongliang; Ding, Jianping; He, Sailing

    2015-01-01

    A caustic vector vortex optical field is experimentally generated and demonstrated by a caustic-based approach. The desired caustic with arbitrary acceleration trajectories, as well as the structured states of polarization (SoP) and vortex orders located in different positions in the field cross-section, is generated by imposing the corresponding spatial phase function in a vector vortex optical field. Our study reveals that different spin and orbital angular momentum flux distributions (including opposite directions) in different positions in the cross-section of a caustic vector vortex optical field can be dynamically managed during propagation by intentionally choosing the initial polarization and vortex topological charges, as a result of the modulation of the caustic phase. We find that the SoP in the field cross-section rotates during propagation due to the existence of the vortex. The unique structured feature of the caustic vector vortex optical field opens the possibility of multi-manipulation of optical angular momentum fluxes and SoP, leading to more complex manipulation of the optical field scenarios. Thus this approach further expands the functionality of an optical system. PMID:26024434

  3. Assessment of the Breakup of the Antarctic Polar Vortex in Two New Chemistry-Climate Models

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Newman, P. A.; Oman, L. D.; Li, F.; Morgenstern, O.; Braesicke, P.; Pyle, J. A.

    2010-01-01

    Successful simulation of the breakup of the Antarctic polar vortex depends on the representation of tropospheric stationary waves at Southern Hemisphere middle latitudes. This paper assesses the vortex breakup in two new chemistry-climate models (CCMs). The stratospheric version of the UK Chemistry and Aerosols model is able to reproduce the observed timing of the vortex breakup. Version 2 of the Goddard Earth Observing System (GEOS V2) model is typical of CCMs in that the Antarctic polar vortex breaks up too late; at 10 hPa, the mean transition to easterlies at 60 S is delayed by 12-13 days as compared with the ERA-40 and National Centers for Environmental Prediction reanalyses. The two models' skill in simulating planetary wave driving during the October-November period accounts for differences in their simulation of the vortex breakup, with GEOS V2 unable to simulate the magnitude and tilt of geopotential height anomalies in the troposphere and thus underestimating the wave driving. In the GEOS V2 CCM the delayed breakup of the Antarctic vortex biases polar temperatures and trace gas distributions in the upper stratosphere in November and December.

  4. Stratospheric water vapour and temperature variability and their effect on polar stratospheric cloud formation and existence in the Arctic

    NASA Astrophysics Data System (ADS)

    Khosrawi, Farahnaz; Urban, Joachim; Lossow, Stefan; Stiller, Gabriele; Weigel, Katja; Braesicke, Peter; Pitts, Michael C.; Murtagh, Donal

    2015-04-01

    Based on more than 10-years of satellite measurements from UARS/HALOE, Envisat/MIPAS, Odin/SMR, Aura/MLS and SciSat/ACE-FTS we investigate water vapour (H2O) variability in the northern hemisphere polar regions. We find from the observations a connection between cold winters and enhanced water vapour mixing ratios in the lower polar stratosphere (475 to 525 K). We perform a sensitivity study along air parcel trajectories to test how an increase of stratospheric water vapour of 1 ppmv or a temperature decrease of 1 K affects the time period during which polar stratospheric clouds (PSCs) can be formed and exist. Air parcel trajectories were calculated 6-days backward in time. The trajectories were started at the time and locations where PSCs were observed by CALIPSO (Cloud Aerosol Lidar and Infrared Pathfinder satellite observations) during the Arctic winter 2010/2011. We test the sensitivity of PSCs formation and existence to changes in H2O and temperature based on PSC observations during this winter since it was one of the coldest Arctic winters in the last decade. The polar vortex persisted over a period of four months, thus leading to extensive PSC formation. During this winter PSCs were detected by CALIPSO on 42 days. In total, 738 trajectories were calculated and analysed. The resulting statistic derived from the air parcel trajectories shows a clear prolongation of the time period where PSCs can be formed and exist when the temperature in the stratosphere is decreased by 1 K and H2O is increased by 1 ppmv. We derive an increase in time where the stratospheric air is exposed to temperatures below Tice and TNAT, respectively, by ~6000 h. Thus, changes in stratospheric water vapour and temperature can prolong PSC formation and existence and thus have a significant influence on the chemistry of the polar stratosphere.

  5. PolarPortal.org Communicates Real-Time Developments in the Arctic

    NASA Astrophysics Data System (ADS)

    Langen, P. L.; Andersen, S. B.; Andersen, K. K.; Andersen, M. L.; Ahlstrom, A. P.; van As, D.; Barletta, V. R.; Box, J. E.; Citterio, M.; Colgan, W. T.; Dybkjær, G.; Forsberg, R.; Høyer, J. L.; Jensen, M. B.; Kliem, N.; Mottram, R.; Nielsen, K. P.; Olesen, M.; Quaglia, F. C.; Rasmussen, T. A.; Rodehacke, C. B.; Stendel, M.; Sandberg Sørensen, L.; Tonboe, R. T.

    2014-12-01

    PolarPortal.org was launched in June 2013 by a consortium of Danish institutions, including the Danish Meteorological Institute (DMI), the Geological Survey of Denmark and Greenland (GEUS) and the National Space Institute at the Technical University of Denmark (DTU-Space). Polar Portal is a single web portal presenting a wide range of near real-time information on both the Greenland ice sheet and Arctic sea-ice in a format geared for non-specialists. Polar Portal aims to meet widespread public interest in a diverse range of climate-cryosphere processes in the Arctic: What is the present Greenland ice sheet contribution to sea level rise? How quickly are outlet glaciers retreating or advancing right now? How extensive is Arctic sea-ice or how warm is the Arctic Ocean at this moment? Although public interest in such topics is widely acknowledged, an important primary task for the scientists behind Polar Portal was collaborating with media specialists to establish the knowledge range of the general public on these topics, in order for Polar Portal to appropriately present useful climate-cryosphere information. Consequently, Polar Portal is designed in a highly visual exploratory format, where individual data products are accompanied by plain written summaries, with hyperlinks to relevant journal papers for more scrutinizing users. Numerous satellite and in situ observations, together with model output, are channeled daily into the Greenland ice sheet and Arctic sea-ice divisions of Polar Portal.

  6. Barotropic simulation of large-scale mixing in the Antarctic polar vortex

    NASA Technical Reports Server (NTRS)

    Bowman, Kenneth P.

    1993-01-01

    Theory and observations suggest that the Antarctic polar vortex is relatively isolated from midlatitudes, although others have interpreted the observations to indicate that there is substantial mixing from the interior of the vortex into middle latitudes. The equivalent barotropic model of Salby et al. is used to study quasi-horizontal mixing by the large-scale flow in the lower stratosphere during Southern Hemisphere spring, which is when the Antarctic ozone hole appears and disappears. The model is forced by relaxation to observed climatological monthly mean zonal-mean winds and by an idealized wave 1 or 2 forcing at the lower boundary. Mixing and transport are diagnosed primarily through Lagrangian tracer trajectories. For September, October, and November basic states, there is little or no mixing in the interior of the vortex. Mixing occurs near the critical lines for the waves: in the tropics and subtropics for a stationary wave 1, and in midlatitudes on the equatorial flank of the jet for an eastward-moving wave 2. For the December basic state, the wave 2 forcing rapidly mixes the interior of the vortex. Mixing of Lagrangian tracer particles can be significant even when the waves do not `break', as evidenced by the potential vorticity field. In the model there does not appear to be any significant transport of air out of the interior of the polar vortex prior to the vortex breakdown. The principal factor that leads to the vortex breakdown and mixing of the vortex interior is the deceleration of the jet to the point where winds in the interior of the vortex are close to the phase velocity of the wavenumber 2 forcing. The tracer transport is very similar to many aspects of the behavior of the total ozone field during the spring season.

  7. Numerical simulation study of polar lows in Russian Arctic: dynamical characteristics

    NASA Astrophysics Data System (ADS)

    Verezemskaya, Polina; Baranyuk, Anastasia; Stepanenko, Victor

    2015-04-01

    Polar Lows (hereafter PL) are intensive mesoscale cyclones, appearing above the sea surface, usually behind the arctic front and characterized by severe weather conditions [1]. All in consequence of the global warming PLs started to emerge in the arctic water area as well - in summer and autumn. The research goal is to examine PLs by considering multisensory data and the resulting numerical mesoscale model. The main purpose was to realize which conditions induce PL development in such thermodynamically unusual season and region as Kara sea. In order to conduct the analysis we used visible and infrared images from MODIS (Aqua). Atmospheric water vapor V, cloud liquid water Q content and surface wind fields W were resampled by examining AMSR-E microwave radiometer data (Aqua)[2], the last one was additionally extracted from QuickSCAT scatterometer. We have selected some PL cases in Kara sea, appeared in autumn of 2007-2008. Life span of the PL was between 24 to 36 hours. Vortexes' characteristics were: W from 15m/s, Q and V values: 0.08-0.11 kg/m2 and 8-15 kg/m2 relatively. Numerical experiments were carried out with Weather Research and Forecasting model (WRF), which was installed on supercomputer "Lomonosov" of Research Computing Center of Moscow State University [3]. As initial conditions was used reanalysis data ERA-Interim from European Centre for Medium-Range Weather Forecasts. Numerical experiments were made with 5 km spatial resolution, with Goddard center microphysical parameterization and explicit convection simulation. Modeling fields were compared with satellite observations and shown good accordance. Than dynamic characteristics were analyzed: evolution of potential and absolute vorticity [4], surface heat and momentum fluxes, and CAPE and WISHE mechanisms realization. 1. Polar lows, J. Turner, E.A. Rasmussen, 612, Cambridge University press, Cambridge, 2003. 2. Zabolotskikh, E. V., Mitnik, L. M., & Chapron, B. (2013). New approach for severe marine weather study using satellite passive microwave sensing. Geophysical Research Letters, 40(13), 3347-3350. doi:10.1002/grl.50664 3. V. Sadovnichy, A. Tikhonravov, Vl. Voevodin, and V. Opanasenko "Lomonosov": Supercomputing at Moscow State University. In Contemporary High Performance Computing: From Petascale toward Exascale (Chapman & Hall/CRC Computational Science), pp.283-307, Boca Raton, USA, CRC Press, 2013. 4. B. J. Hoskins, M.E. McIntyre, A.W. Robertson, On the use and significance of isentropic potential vorticity maps, Quarterly journal of the Royal Meteorological Society, OCTOBER 1985, ? 470, vol. 111(6).

  8. Polar stratospheric clouds over Finland in the 2012/2013 Arctic winter measured by two Raman lidars

    NASA Astrophysics Data System (ADS)

    Hoffmann, Anne; Giannakaki, Eleni; Kivi, Rigel; Schrems, Otto; Immler, Franz; Komppula, Mika

    2013-04-01

    Already in December 2012, the Arctic stratospheric vortex reached temperatures sufficiently low for polar stratospheric cloud (PSC) formation over wide areas of Northern Europe and whole Finland. Within Finland, stratospheric aerosol lidar measurements have been and are performed with two Raman lidar systems, the PollyXT, owned by the Finnish Meteorological Institute (FMI) and situated well below the Arctic circle close to Kuopio (63 N, 27 E) and the MARL lidar owned by the Alfred-Wegener-Institute for Polar and Marine Research (AWI), and situated at the FMI Arctic Research Centre in Sodankylä (67 N, 26 E). The PollyXT has been designed as an autonomous tropospheric lidar system, but it has proven to be able to detect aerosol backscatter and depolarization at least as high up as 25 km. Measurements are ongoing as far as low clouds allow for stratospheric analysis with both lidars until the end of PSC season in February. For the winter 2012/2013, PSC occurrence frequency, types and characteristics will be determined. Comparative analysis with Calipso lidar profiles covering Finland will be performed. Preliminary results from December 17-24 show PSCs detected in Kuopio during seven days with the PollyXT lidar. The altitude of the clouds varied in the range of 17-25 km. In Sodankylä the measurements were running on one day during the period and PSCs were observed between altitudes 17-25 km. For the same time period (December 17-24, 2012) CALIPSO has observed stratospheric layers at all overpasses over Finland (9 tracks on five days). The clouds were observed between 18.5 and 26 km, with varying geometric and optical thickness.

  9. Spatial, temporal, and vertical variability of polar stratospheric ozone loss in the Arctic winters 2004/05-2009/10

    NASA Astrophysics Data System (ADS)

    Kuttippurath, J.; Godin-Beekmann, S.; Lefèvre, F.; Goutail, F.

    2010-06-01

    The stratospheric ozone loss during the Arctic winters 2004/05-2009/10 is investigated by using high resolution simulations from the chemical transport model Mimosa-Chim and observations from Microwave Limb Sounder (MLS) on Aura by the passive tracer technique. The winter 2004/05 was the coldest of the series with strongest chlorine activation. The ozone loss diagnosed from both model and measurements inside the polar vortex at 475 K ranges from ~1-0.7 ppmv in the warm winter 2005/06 to 1.7 ppmv in the cold winter 2004/05. Halogenated (chlorine and bromine) catalytic cycles contribute to 75-90% of the accumulated ozone loss at this level. At 675 K the lowest loss of ~0.4 ppmv is computed in 2008/09 from both simulations and observations and, the highest loss is estimated in 2006/07 by the model (1.3 ppmv) and in 2004/05 by MLS (1.5 ppmv). Most of the ozone loss (60-75%) at this level results from cycles catalysed by nitrogen oxides (NO and NO2) rather than halogens. At both 475 and 675 K levels the simulated ozone evolution inside the polar vortex is in reasonably good agreement with the observations. The ozone total column loss deduced from the model calculations at the MLS sampling locations inside the vortex ranges between 40 DU in 2005/06 and 94 DU in 2004/05, while that derived from observations ranges between 37 DU and 111 DU in the same winters. These estimates from both Mimosa-Chim and MLS are in general good agreement with those from the ground-based UV-VIS (ultra violet-visible) ozone loss analyses for the respective winters.

  10. EOS Microwave Limb Sounder Observations of the Antarctic Polar Vortex Breakup in 2004

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Santee, M. L.; Livesey, N. J.; Froidevaux, L.; Read, W. G.; Pumphrey, H. C.; Waters, J. W.; Pawson, S.

    2005-01-01

    Observations from the Microwave Limb Sounder (MLS) on NASA's new Aura satellite give an unprecedentedly detailed picture of the spring Antarctic polar vortex breakup throughout the stratosphere. HCl is a particularly valuable tracer in the lower stratosphere after chlorine deactivation. MLS HCl, N2O, H2O broke up in the upper stratosphere by early October, in the midstratosphere by early November, and in the lower stratosphere by late December. The subvortex broke up just a few days later than the lower stratospheric vortex. Vortex remnants persisted in the midstratosphere through December, but only through early January 2005 in the lower stratosphere. MLS N2O observations show diabatic descent continuing throughout November, with evidence of weak ascent after late October in the lower stratospheric vortex core.

  11. The possible biotic origin of polar sunrise Arctic "bromine explosion"

    E-print Network

    Iudin, M

    2008-01-01

    The Arctic phenomenon of the sunrise bromine explosion in atmospheric boundary layer is likely to belong to the group of the global atmosphere and climate factors. The global atmosphere and climate factors are identified as the most crucial and fundamental processes in Earth atmosphere and climate evolution. They affect normal climate and are able to control climate changes over geological time scales. This study deals with the hypothesis of the microbial origin of natural Arctic bromine emissions. Most of Arctic surface is permafrost. Some of the Arctic permafrost is very old. It contains huge amounts of viable ancient microbial life forms survived over geological times. The erosion of permafrost is a hypothetical precursor to bromine injection to Arctic troposphere. The controlled experiment has been suggested. GOME satellite data from 1996 to 2000 has been discussed. Bromine biosphere atmosphere ascertaining would require the interdisciplinary research of experimental findings and observations in extreme A...

  12. The association between stratospheric weak polar vortex events and cold air outbreaks

    E-print Network

    Kolstad, E W; Scaife, A A

    2009-01-01

    Previous studies have identified an association between near-surface temperature anomalies in the Northern Hemisphere and weak stratospheric polar westerlies. Large regions in northern Asia, Europe and North America have been found to cool in the mature and late stages of stratospheric weak vortex events. A substantial part of the temperature changes are associated with changes to the tropospheric Northern Annular Mode and North Atlantic Oscillation pressure patterns. The apparent coupling between the stratosphere and the troposphere may be of relevance for weather forecasting, but only if the temporal and spatial nature of the coupling is known. Here we show, using 51 winters of re-analysis data, that the tropospheric temperature development relative to stratospheric weak polar vortex events goes through a series of well-defined stages, including geographically distinct cold air outbreaks. At the inception of weak vortex events, a precursor signal in the form of a strong high-pressure anomaly is found over N...

  13. Effect of recent sea surface temperature trends on the Arctic stratospheric vortex

    NASA Astrophysics Data System (ADS)

    Garfinkel, C. I.; Hurwitz, M. M.; Oman, L. D.

    2015-06-01

    Comprehensive chemistry-climate model experiments and observational data are used to show that up to half of the satellite era early springtime cooling trend in the Arctic lower stratosphere was caused by changing sea surface temperatures (SSTs). An ensemble of experiments forced only by changing SSTs is compared to an ensemble of experiments in which both the observed SSTs and chemically and radiatively active trace species are changing. By comparing the two ensembles, it is shown that warming of Indian Ocean, North Pacific, and North Atlantic SSTs and cooling of the tropical Pacific have strongly contributed to recent polar stratospheric cooling in late winter and early spring. When concentrations of ozone-depleting substances and greenhouse gases are fixed, polar ozone concentrations show a small but robust decline due to changing SSTs. Ozone loss is larger in the presence of changing concentrations of ozone-depleting substances and greenhouse gases. The stratospheric changes can be understood by examining the tropospheric height and heat flux anomalies generated by the anomalous SSTs. Finally, recent SST changes have contributed to a decrease in the frequency of late winter stratospheric sudden warmings.

  14. An International Polar Year Adventure in the Arctic

    NASA Astrophysics Data System (ADS)

    Wartes, D.

    2008-12-01

    RAHI, the Rural Alaska Honors Institute at the University of Alaska Fairbanks began in 1983 after a series of meetings between the Alaska Federation of Natives and the University of Alaska, to discuss the retention rates of Alaska Native and rural students. RAHI is a six-week college-preparatory summer bridge program on the University of Alaska Fairbanks campus for Alaska Native and rural high school juniors and seniors. The program's student body is approximately 94 percent Alaska Native. RAHI students take classes that earn them seven to ten college credits, thus giving them a head start on college. Courses include: writing, study skills, desk top publishing, Alaska Native dance or swimming, and a choice of biochemistry, math, business, or engineering. A program of rigorous academic activity combines with social, cultural, and recreational activities to make up the RAHI program of early preparation for college. Students are purposely stretched beyond their comfort levels academically and socially to prepare for the big step from home or village to a large culturally western urban campus. They are treated as honors students and are expected to meet all rigorous academic and social standards set by the program. All of this effort and activity support the principal goal of RAHI: promoting academic success for rural students in college. Over 26 years, 1,200 students have attended the program. Sixty percent of RAHI's alumni have entered four-year academic programs. Over 245 have earned a bachelor's degree, thirty-one have earned master's degrees, and seven have graduated with professional degrees (J.D., Pharm., or M.D.), along with 156 associate degrees and certificates. In looking at the RAHI cohort, removing those students who have not been in college long enough to obtain a degree, 27.3 percent of RAHI alums have received a bachelor's degree. An April 2006 report by the American Institutes for Research through the National Science Foundation found that: Rural Native students in the UA system who participated in RAHI are nearly twice as likely to earn a bachelor's degree, than those who did not attend RAHI. The past two summers, in celebration of the International Polar Year, in collaboration with Ilisagvik College, at the completion of the traditional RAHI program, ten RAHI students flew to Barrow for an additional two weeks of study. Five students participated in an archaeological dig and five students performed research with the Barrow Arctic Science Consortium scientists studying climate change. And another student was the Alaskan delegate to the Students on Ice, a 2-week ship-based adventure in northern Canada. In addition, ten students from Greenland visited the program, with plans to more fully participate next summer. This added dimension to the program has proved successful, allowing the students to compare and contrast between their own countries and indigenous perspectives. Global warming was an issue that was hotly debated, as its effects are so evident in the Polar Regions. In the Arctic, one's life is directly tied to the ice and snow. As the ice disappears and/or changes, the Indigenous people have to adapt. RAHI would like to share with you some of the results of this past summer's IPY activities.

  15. Observations of backscatter, particle concentration and frost point in north polar vortex stratospheric clouds

    SciTech Connect

    Rosen, J.M.; Kjome, N.T. ); Oltmans, S.J. )

    1990-08-01

    Near-simultaneous soundings of backscatter, particle size distribution and frost point were obtained in north polar stratospheric clouds (PSCs) near the center of the vortex. The measured particle sizes and concentration in type I PSCs tend to confirm earlier predictions based on remotely sensed properties.

  16. The Effect of Tropospheric Jet Latitude on Coupling between the Stratospheric Polar Vortex and the Troposphere

    E-print Network

    Garfinkel, Chaim I.

    heat flux and zonal length scale, appear to be incapable of explaining the differences in the magnitude) illustrate the impact of natural variations of the polar vortex on tropospheric variability. Extended range accurate treatment of stratospheric ozone to capture recent trends (e.g., Arblaster and Meehl 2006; Son et

  17. Instantaneous three-dimensional thermal structure of the South Polar Vortex of Venus

    NASA Astrophysics Data System (ADS)

    Garate-Lopez, I.; García Muñoz, A.; Hueso, R.; Sánchez-Lavega, A.

    2015-01-01

    The Venus thermal radiation spectrum exhibits the signature of CO2 absorption bands. By means of inversion techniques, those bands enable the retrieval of atmospheric temperature profiles. We have analyzed VIRTIS-M-IR night-side data obtaining high-resolution thermal maps of the Venus south polar region between 55 and 85 km altitudes. This analysis is specific to three Venus Express orbits where the vortex presents different dynamical configurations. The cold collar is clearly distinguishable centered at ?62 km (?100 mbar) altitude level. On average, the cold collar is more than 15 K colder than the pole, but its specific temperature varies with time. In the three orbits under investigation the South Polar Vortex appears as a vertically extended hot region close to the pole and squeezed by the cold collar between altitudes 55 and 67 km but spreading equatorwards at about 74 km. Both the instantaneous temperature maps and their zonal averages show that the top altitude limit of the thermal signature from the vortex is at ?80 km altitude, at least on the night-side of the planet. The upper part of the atmosphere (67-85 km) is more homogeneous and has long-scale horizontal temperature differences of about 25 K over horizontal distances of ?2000 km. The lower part (55-67 km) shows more fine-scale structure, creating the vortex morphology, with thermal differences of up to about 50 K over the same altitude range and ?500 km horizontal distances. This lower part of the atmosphere is highly affected by the upper cloud deck, leading to stronger local temperature variations and larger uncertainties in the retrieval. From the temperature maps, we also study the vertical stability of different atmospheric layers for the three vortex configurations. The static stability is always positive (ST > 0) in the considered altitude range (55-85 km) and in the whole polar vortex. The cold collar is the most vertically stable structure at polar latitudes, while the vortex and sub-polar latitudes show lower stability values. Furthermore, the hot filaments present within the vortex exhibit lower stability values than their surroundings. The layer between 62 and 67 km resulted to be the most stable. These results are in good agreement with conclusions from previous radio occultation analyses.

  18. Polar bear and walrus response to the rapid decline in Arctic sea ice

    USGS Publications Warehouse

    Oakley, K.; Whalen, M.; Douglas, D.; Udevitz, M.; Atwood, T.; Jay, C.

    2012-01-01

    The Arctic is warming faster than other regions of the world due to positive climate feedbacks associated with loss of snow and ice. One highly visible consequence has been a rapid decline in Arctic sea ice over the past 3 decades - a decline projected to continue and result in ice-free summers likely as soon as 2030. The polar bear (Ursus maritimus) and the Pacific walrus (Odobenus rosmarus divergens) are dependent on sea ice over the continental shelves of the Arctic Ocean's marginal seas. The continental shelves are shallow regions with high biological productivity, supporting abundant marine life within the water column and on the sea floor. Polar bears use sea ice as a platform for hunting ice seals; walruses use sea ice as a resting platform between dives to forage for clams and other bottom-dwelling invertebrates. How have sea ice changes affected polar bears and walruses? How will anticipated changes affect them in the future?

  19. Stereographical visualization of a polarization state using weak measurements with an optical-vortex beam

    E-print Network

    Hirokazu Kobayashi; Koji Nonaka; Yutaka Shikano

    2015-08-18

    We propose a stereographical-visualization scheme for a polarization state by two-dimensional imaging of a weak value with a single setup. The key idea is to employ Laguerre-Gaussian modes or an optical vortex beam for a probe state in weak measurement. Our scheme has the advantage that we can extract information on the polarization state from the single image in which the zero-intensity point of the optical vortex beam corresponds to a stereographic projection point of the Poincare sphere. We experimentally perform single-setup weak measurement to validate the stereographical relationship between the polarization state on the Poincare sphere and the location of the zero-intensity point.

  20. Evolution of microwave limb sounder ozone and the polar vortex during winter

    SciTech Connect

    Manney, G.L.; Froidevaux, L.; Waters, J.W.; Zurek, R.W.

    1995-02-01

    The evolution of polar ozone observed by the Upper Atmosphere Research Satellite (UARS) Microwave Limb Sounder (MLS) is described for the northern hemisphere (NH) winters of 1991/1992, 1992/1993, and 1993/1994 and the southern hemisphere (SH) winters of 1992 and 1993. Imterannual and interhemispheric variability in polar ozone evolution are closely related to differences in the polar vortex and to the frequency, duration and strength of stratospheric sudden warmings. Ozone in the midstratospheric vortices increases during the winter, with largest increases associated with stratospheric warmings and a much larger increase in the NH than in the SH. A smaller NH increase was observed in 1993/1994, when the middle stratospheric vortex was stronger. During strong stratospheric warmings in the NH, the upper stratospheric vortex may be so much eroded that it presents little barrier to poleward transport; in contrast, the SH vortex remains strong throughout the stratosphere during wintertime warmings, and ozone increases only below the mixing ratio peak, due to enhanced diabatic descent. Ozone mixing ratios decrease rapidly in the lower stratosphere in both SH late winters, as expected from chemical destruction due to enhanced reactive chlorine. The interplay between dynamics and chemistry is more complex in the NH lower stratosphere and interannual variability is greater. Evidence has previously been shown for chemical ozone destruction in the 1991/1992 and 1992/1993 winters.

  1. Summer in the Martian Arctic: The Phoenix Mars Mission and The International Polar Year

    NASA Astrophysics Data System (ADS)

    Bitter, C.; Buxner, S.

    2008-12-01

    The Phoenix Mars Mission provided a polar analog for Earth which allowed many Education and Public Outreach (E/PO) contexts for learning about the Polar Regions of both planets for new public audiences. This review and dissemination of E/PO products from the Phoenix Mission in support of IPY will include an overview the MARSFEST teacher program, PSIP (Phoenix Student Intern Program) projects, Arctic and Antarctic multimedia tools developed by the Phoenix team, and hands-on activities to support new ideas for learning about the Martian Arctic.

  2. Potential Vorticity of the South Polar Vortex of Venus

    NASA Astrophysics Data System (ADS)

    Garate-Lopez, I.; Hueso, R.; Sánchez-Lavega, A.

    2015-10-01

    The atmospheric vortex at the southern pole of Venus is highly variable in morphology and unpredictable in its dynamical behavior. Using infrared images from the VIRTIS-M instrument onboard Venus Express we have built maps of Ertel's potential vorticity at the lower and upper clouds (altitudes~4 1-45km and ~55-62km above the surface). For this purpose, we have combined the wind field at both clouds'levels and the three-dimensional thermal structure that we previously measured [1, 2].

  3. Spatial, temporal, and vertical variability of polar stratospheric ozone loss in the Arctic winters 2004/2005-2009/2010

    NASA Astrophysics Data System (ADS)

    Kuttippurath, J.; Godin-Beekmann, S.; Lefèvre, F.; Goutail, F.

    2010-10-01

    The polar stratospheric ozone loss during the Arctic winters 2004/2005-2009/2010 is investigated by using high resolution simulations from the chemical transport model Mimosa-Chim and observations from Aura Microwave Limb Sounder (MLS), by applying the passive tracer technique. The winter 2004/2005 shows the coldest temperatures, highest area of polar stratospheric clouds and strongest chlorine activation in 2004/2005-2009/2010. The ozone loss diagnosed from both simulations and measurements inside the polar vortex at 475 K ranges from 0.7 ppmv in the warm winter 2005/2006 to 1.5-1.7 ppmv in the cold winter 2004/2005. Halogenated (chlorine and bromine) catalytic cycles contribute to 75-90% of the ozone loss at this level. At 675 K the lowest loss of 0.3-0.5 ppmv is computed in 2008/2009, and the highest loss of 1.3 ppmv is estimated in 2006/2007 by the model and in 2004/2005 by MLS. Most of the ozone loss (60-75%) at this level results from nitrogen catalytic cycles rather than halogen cycles. At both 475 and 675 K levels the simulated ozone and ozone loss evolution inside the vortex is in reasonably good agreement with the MLS observations. The ozone partial column loss in 350-850 K deduced from the model calculations at the MLS sampling locations inside the polar vortex ranges between 43 DU in 2005/2006 and 109 DU in 2004/2005, while those derived from the MLS observations range between 26 DU and 115 DU for the same winters. The partial column ozone depletion derived in that vertical range is larger than that estimated in 350-550 K by 19±7 DU on average, mainly due to NOx chemistry. The column ozone loss estimates from both Mimosa-Chim and MLS in 350-850 K are generally in good agreement with those derived from ground-based ultraviolet-visible spectrometer total ozone observations for the respective winters, except in 2010.

  4. Polar bear maternal den habitat in the Arctic National Wildlife Refuge, Alaska

    USGS Publications Warehouse

    Durner, G.M.; Amstrup, Steven C.; Ambrosius, K.J.

    2006-01-01

    Polar bears (Ursus maritimus) give birth during mid-winter in dens of ice and snow. Denning polar bears subjected to human disturbances may abandon dens before their altricial young can survive the rigors of the Arctic winter. Because the Arctic coastal plain of Alaska is an area of high petroleum potential and contains existing and planned oil field developments, the distribution of polar bear dens on the plain is of interest to land managers. Therefore, as part of a study of denning habitats along the entire Arctic coast of Alaska, we examined high-resolution aerial photographs (n = 1655) of the 7994 km2 coastal plain included in the Arctic National Wildlife Refuge (ANWR) and mapped 3621 km of bank habitat suitable for denning by polar bears. Such habitats were distributed uniformly and comprised 0.29% (23.2 km2) of the coastal plain between the Canning River and the Canadian border. Ground-truth sampling suggested that we had correctly identified 91.5% of bank denning habitats on the ANWR coastal plain. Knowledge of the distribution of these habitats will help facilitate informed management of human activities and minimize disruption of polar bears in maternal dens.

  5. Polarization-selective vortex-core switching by tailored orthogonal Gaussian-pulse currents

    SciTech Connect

    Jung, H.; Choi, Y. -S.; Yoo, M. -W.; Im, M. -Y.; Kim, S. -K.

    2010-10-13

    We experimentally demonstrate low-power-consumption vortex-core switching in magnetic nanodisks using tailored rotating magnetic fields produced with orthogonal and unipolar Gaussian-pulse currents. The optimal width of the orthogonal pulses and their time delay are found, from analytical and micromagnetic numerical calculations, to be determined only by the angular eigenfrequency {omega}{sub D} for a given vortex-state disk of polarization p, such that {sigma}=1/{omega}{sub D} and ?{Delta}t={pi}/2 p/{omega}{sub D} . The estimated optimal pulse parameters are in good agreement with the experimental results. This work lays a foundation for energy-efficient information recording in vortex-core cross-point architecture.

  6. Chemical Depletion of Lower Stratospheric Ozone in the 1992-1993 Northern Winter Vortex

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Froidevaux, L.; Waters, J. W.; Zurek, R. W.; Read, W. G.; Elson, L. S.; Kumer, J. B.; Mergenthaler, J. L.; Roche, A. E.; O'Neill, A.; Harwood, R. S.; MacKenzie, I.; Swinbank, R.

    1994-01-01

    Satellite observations of ozone and chlorine monoxide in the Arctic lower stratosphere during winter 1992-1993 are compared with observations during other winters, observations of long-lived tracers and the evolution of the polar vortex. Chlorine in the lower stratospheric vortex during February 1993 was mostly in chemically reactive forms.

  7. Observational constraints on the tropospheric and near-surface winter signature of the Northern Hemisphere stratospheric polar vortex

    E-print Network

    Graf, Hans-F.; Zanchettin, Davide; Timmreck, Claudia; Bittner, Matthias

    2014-03-07

    A composite analysis of Northern Hemisphere’s mid-winter tropospheric anomalies under the conditions of strong and weak stratospheric polar vortex was performed on NCEP/NCAR reanalysis data from 1948 to 2013 considering, as additional grouping...

  8. Arctic Research and Writing: A Lasting Legacy of the International Polar Year

    ERIC Educational Resources Information Center

    Englert, Karl; Coon, Brian; Hinckley, Matt; Pruis, Matt

    2009-01-01

    Recently, senior-level physics students joined thousands of scientists from over 60 nations to examine a wide range of physical, biological, and social research topics as part of the International Polar Year (IPY). Through a National Science Foundation (NSF)-funded research project, these students applied physics concepts to the study of Arctic

  9. NSF Antarctic and Arctic Data Consortium; Scientific Research Support & Data Services for the Polar Community

    NASA Astrophysics Data System (ADS)

    Morin, P. J.; Pundsack, J. W.; Carbotte, S. M.; Tweedie, C. E.; Grunow, A.; Lazzara, M. A.; Carpenter, P.; Sjunneskog, C. M.; Yarmey, L.; Bauer, R.; Adrian, B. M.; Pettit, J.

    2014-12-01

    The U.S. National Science Foundation Antarctic & Arctic Data Consortium (a2dc) is a collaboration of research centers and support organizations that provide polar scientists with data and tools to complete their research objectives. From searching historical weather observations to submitting geologic samples, polar researchers utilize the a2dc to search andcontribute to the wealth of polar scientific and geospatial data.The goals of the Antarctic & Arctic Data Consortium are to increase visibility in the research community of the services provided by resource and support facilities. Closer integration of individual facilities into a "one stop shop" will make it easier for researchers to take advantage of services and products provided by consortium members. The a2dc provides a common web portal where investigators can go to access data and samples needed to build research projects, develop student projects, or to do virtual field reconnaissance without having to utilize expensive logistics to go into the field.Participation by the international community is crucial for the success of a2dc. There are 48 nations that are signatories of the Antarctic Treaty, and 8 sovereign nations in the Arctic. Many of these organizations have unique capabilities and data that would benefit US ­funded polar science and vice versa.We'll present an overview of the Antarctic & Arctic Data Consortium, current participating organizations, challenges & opportunities, and plans to better coordinate data through a geospatial strategy and infrastructure.

  10. Large amplitude spin torque vortex oscillations at zero external field using a perpendicular spin polarizer

    SciTech Connect

    Dussaux, A.; Rache Salles, B.; Jenkins, A. S.; Bortolotti, P.; Grollier, J.; Cros, V.; Fert, A.; Khvalkovskiy, A. V.; Kubota, H.; Fukushima, A.; Yakushiji, K.; Yuasa, S.

    2014-07-14

    We investigate the microwave response of a spin transfer vortex based oscillator in a magnetic tunnel junction with an in-plane reference layer combined with a spin valve with an out-of-plane magnetization spin polarizing layer. The main advantage of this perpendicular spin polarizer is to induce a large spin transfer force even at zero magnetic field, thus leading to a record emitted power (up to 0.6??W) associated to a very narrow spectral linewidth of a few hundreds of kHz. The characteristics of this hybrid vortex based spin transfer nano-oscillator obtained at zero field and room temperature are of great importance for applications based on rf spintronic devices as integrated and tunable microwave source and/or microwave detector.

  11. Antarctic ozone variability inside the polar vortex estimated from balloon measurements

    NASA Astrophysics Data System (ADS)

    Parrondo, M. C.; Gil, M.; Yela, M.; Johnson, B. J.; Ochoa, H. A.

    2014-01-01

    Thirteen years of ozone soundings at the Antarctic Belgrano II station (78° S, 34.6° W) have been analysed to establish a climatology of stratospheric ozone and temperature over the area. The station is inside the polar vortex during the period of development of chemical ozone depletion. Weekly periodic profiles provide a suitable database for seasonal characterization of the evolution of stratospheric ozone, especially valuable during wintertime, when satellites and ground-based instruments based on solar radiation are not available. The work is focused on ozone loss rate variability (August-October) and its recovery (November-December) at different layers identified according to the severity of ozone loss. The time window selected for the calculations covers the phase of a quasi-linear ozone reduction, around day 220 (mid-August) to day 273 (end of September). Decrease of the total ozone column over Belgrano during spring is highly dependent on the meteorological conditions. Largest depletions (up to 59%) are reached in coldest years, while warm winters exhibit significantly lower ozone loss (20%). It has been found that about 11% of the total O3 loss, in the layer where maximum depletion occurs, takes place before sunlight has arrived, as a result of transport to Belgrano of air from a somewhat lower latitude, near the edge of the polar vortex, providing evidence of mixing inside the vortex. Spatial homogeneity of the vortex has been examined by comparing Belgrano results with those previously obtained for South Pole station (SPS) for the same altitude range and for 9 yr of overlapping data. Results show more than 25% higher ozone loss rate at SPS than at Belgrano. The behaviour can be explained taking into account (i) the transport to both stations of air from a somewhat lower latitude, near the edge of the polar vortex, where sunlight reappears sooner, resulting in earlier depletion of ozone, and (ii) the accumulated hours of sunlight, which become much greater at the South Pole after the spring equinox. According to the variability of the ozone hole recovery, a clear connection between the timing of the breakup of the vortex and the monthly ozone content was found. Minimum ozone concentration of 57 DU in the 12-24 km layer remained in November, when the vortex is more persistent, while in years when the final stratospheric warming took place "very early", mean integrated ozone rose by up to 160-180 DU.

  12. Lidar measurements of ozone and aerosol distributions during the 1992 airborne Arctic stratospheric expedition

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Butler, Carolyn F.; Fenn, Marta A.; Grant, William B.; Ismail, Syed; Carter, Arlen F.

    1994-01-01

    The NASA Langley airborne differential absorption lidar system was operated from the NASA Ames DC-8 aircraft during the 1992 Airborne Arctic Stratospheric Expedition to investigate the distribution of stratospheric aerosols and ozone (O3) across the Arctic vortex from January to March 1992. Aerosols from the Mt. Pinatubo eruption were found outside and inside the Arctic vortex with distinctly different scattering characteristics and spatial distributions in the two regions. The aerosol and O3 distributions clearly identified the edge of the vortex and provided additional information on vortex dynamics and transport processes. Few polar stratospheric clouds were observed during the AASE-2; however, those that were found had enhanced scattering and depolarization over the background Pinatubo aerosols. The distribution of aerosols inside the vortex exhibited relatively minor changes during the AASE-2. Ozone depletion inside the vortex as limited to less than or equal to 20 percent in the altitude region from 15-20 km.

  13. The 4-Day Wave and Transport of UARS Tracers in the Austral Polar Vortex.

    NASA Astrophysics Data System (ADS)

    Manney, G. L.; Orsolini, Y. J.; Pumphrey, H. C.; Roche, A. E.

    1998-12-01

    Upper Atmosphere Research Satellite tracer data and isentropic transport calculations using U.K. Meteorological Office winds initialized with these data show evidence of eastward-traveling waves in the polar upper stratosphere in late austral winter 1992. Microwave Limb Sounder (MLS) H2O from prototype iterative retrievals shows a 4-day wave signal at levels from 1.5 to 0.1 hPa; a 4-day wave signal was not obvious in production retrievals of MLS H2O. At 1800 K, the 4-day wave signal in MLS H2O has a double-peaked structure in latitude, which is reproduced in isentropic transport calculations. The time evolution, amplitude, and phase of the 4-day wave in the transport calculations agree well with observations at high latitudes; the position and shape of the polar vortex and of H2O drawn up around the vortex are reproduced by the transport calculations. Spectral analyses of the Cryogen Limb Array Etalon Spectrometer (CLAES) CH4 are dominated by more slowly eastward-moving waves (6-10 days), but a weak 4-day wave signature is also present between 1.5 and 4 hPa. Transport calculations initialized with CH4 show similar eastward-traveling signals, good agreement with the phase of the observed signals, and overall agreement with the observed position of the vortex. The qualitative success of the transport calculations in reproducing the phase and overall time evolution of high-latitude eastward-traveling waves in the polar upper stratosphere indicates that the winds used for the transport calculations are generally reliable, and that the eastward-traveling waves identified in the MLS H2O and CLAES CH4 originate to a large extent from horizontal transport processes. Examination of the vertical structure of potential vorticity shows periods when at the highest levels studied (around 1800 K), the 4-day wave is responsible for the main motion of the vortex, whereas at lower levels (at and below 1400 K) the vortex motion is characterized by a slower eastward progression, and the 4-day wave signal contributes to motions that are confined inside the vortex.

  14. Optimally coherent sets in geophysical flows: a transfer-operator approach to delimiting the stratospheric polar vortex.

    PubMed

    Santitissadeekorn, Naratip; Froyland, Gary; Monahan, Adam

    2010-11-01

    The "edge" of the Antarctic polar vortex is known to behave as a barrier to the meridional (poleward) transport of ozone during the austral winter. This chemical isolation of the polar vortex from the middle and low latitudes produces an ozone minimum in the vortex region, intensifying the ozone hole relative to that which would be produced by photochemical processes alone. Observational determination of the vortex edge remains an active field of research. In this paper, we obtain objective estimates of the structure of the polar vortex by introducing a technique based on transfer operators that aims to find regions with minimal external transport. Applying this technique to European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-40 three-dimensional velocity data, we produce an improved three-dimensional estimate of the vortex location in the upper stratosphere where the vortex is most pronounced. This computational approach has wide potential application in detecting and analyzing mixing structures in a variety of atmospheric, oceanographic, and general fluid dynamical settings. PMID:21230580

  15. Projected Polar Bear Sea Ice Habitat in the Canadian Arctic Archipelago

    PubMed Central

    Hamilton, Stephen G.; Castro de la Guardia, Laura; Derocher, Andrew E.; Sahanatien, Vicki; Tremblay, Bruno; Huard, David

    2014-01-01

    Background Sea ice across the Arctic is declining and altering physical characteristics of marine ecosystems. Polar bears (Ursus maritimus) have been identified as vulnerable to changes in sea ice conditions. We use sea ice projections for the Canadian Arctic Archipelago from 2006 – 2100 to gain insight into the conservation challenges for polar bears with respect to habitat loss using metrics developed from polar bear energetics modeling. Principal Findings Shifts away from multiyear ice to annual ice cover throughout the region, as well as lengthening ice-free periods, may become critical for polar bears before the end of the 21st century with projected warming. Each polar bear population in the Archipelago may undergo 2–5 months of ice-free conditions, where no such conditions exist presently. We identify spatially and temporally explicit ice-free periods that extend beyond what polar bears require for nutritional and reproductive demands. Conclusions/Significance Under business-as-usual climate projections, polar bears may face starvation and reproductive failure across the entire Archipelago by the year 2100. PMID:25426720

  16. The Arctic polar stratospheric cloud aerosol - Aircraft measurements of reactive nitrogen, total water, and particles

    NASA Technical Reports Server (NTRS)

    Kawa, S. R.; Fahey, D. W.; Kelly, K. K.; Dye, J. E.; Baumgardner, D.; Gandrud, B. W.; Loewenstein, M.; Ferry, G. V.; Chan, K. R.

    1992-01-01

    In situ aircraft measurements in the lower stratosphere are used to investigate the reactive nitrogen, NO(y), total water, and particle components of the polar stratospheric cloud (PSC) aerosol in the Arctic. The results are compared to findings from the Antarctic derived using similar measurements and interpretive techniques. The Arctic data show that particle volume well above background values is present at temperatures above the frostpoint, confirming the result from the Antarctic that the observed PSCs are not water ice particles. NO(y) measurements inside a PSC are enhanced above ambient values consistent with anisokinetic sampling of particles containing NO(y). In the Arctic data over long segments of several flights, calculations show saturation with respect to nitric acid trihydrate without significant PSC particle growth above background.

  17. IHY-IPY conference report from Polar Gateways Arctic Circle Sunrise 2008

    NASA Astrophysics Data System (ADS)

    Cooper, John; Kauristie, Kirsti; Weatherwax, Allan; Thompson, Barbara; Sheehan, Glenn; Smith, Roger; Sandahl, Ingrid

    Polar, heliophysical, and planetary science topics related to the International Heliophysical and Polar Years 2007-2009 were addressed during this unique circumpolar conference hosted January 23-29, 2008 at the new Barrow Arctic Research Center of the Barrow Arctic Science Consortium in Barrow, Alaska. Science presentations spanned the solar system from the polar Sun and heliospheric environment to Earth, Moon, Mars, Jupiter, Saturn, the Kuiper Belt, and the solar wind termination shock now crossed by both Voyager spacecraft. Many of the science presentations were made remotely via video conference or teleconference from Sweden, Norway, Russia, Canada, Antarctica, and the United States, spanning up to thirteen time zones (Alaska to Russia) at various times during the conference. U.S. remote contributions came from the University of Alaska at Fairbanks, the University of California at Berkeley, the University of Arizona, NASA Jet Propulsion Laboratory, and NASA Goddard Space Flight Center. Convening during the first week of 2008 Arctic sunrise at Barrow, this conference served as a prelude that year to international Sun-Earth Day celebrations for IHY, while also commemorating Barrow scientific and native cultural support for the first International Polar Year 1882-1883. Extensive educational outreach activities were conducted with the local Barrow and Alaska North Slope communities and through the NASA Digital Learning Network live from the "top of the world" at Barrow. The conference proceedings are Internet accessible via the home page at http://polargateways2008.org/.

  18. Net Ecosystem Production of Polar Desert and Wetland Landscapes in the Rapidly Changing Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Emmerton, C. A.; St Louis, V. L.; Humphreys, E.; Barker, J. D.; Gamon, J. A.; Pastorello, G.

    2014-12-01

    A rapidly warming and wetting Arctic climate is changing the net ecosystem production (NEP) of northern landscapes and subsequent exchange of carbon dioxide (CO2) with the atmosphere. Assessments of northern terrestrial NEP have focused mostly on the rich peatland landscapes of the low Arctic, with far fewer studies from expansive, but sparse, high Arctic polar landscapes. Consequently, how these ecosystems may respond to a warming and wetting climate is still a key gap in our understanding of global carbon feedbacks. We used multi-season eddy covariance measurements to quantify growing season (June to September) NEP on contrasting polar desert and meadow wetland landscapes near Lake Hazen on northern Ellesmere Island (81ºN), in Canada's high Arctic. We also used variation in contemporary NEP and weather to improve our understanding of potential future carbon cycling in a warmer and wetter high Arctic climate. During a typical growing season, we found that a dry polar desert landscape accumulated only 6.6±1.2 g C m-2 similar to other high Arctic sites and consistent with cold, barren soils with weak plant growth. Desert NEP coincided strongest with landscape moisture, rather than heating, with increased NEP occurring during drier conditions when soil heterotrophic rates were lowest. With a nearly constant but varying supply of water, the productive meadow wetland accumulated 13 times more carbon (86.1±16.9 g C m-2) than the desert during the growing season. NEP at the wetland was similar to comparable landscapes much further south, owing to continuous 24-hour daylight and typically clear-skies surrounding Lake Hazen. Wetland soils showed a consistent strong burst of CO2 to the atmosphere each spring (min. NEP: -2.5 µmol CO2 s-1 m-2) and a well-defined peak in July productivity (3.9-4.4 µmol CO2 s-1 m-2). Wetland NEP associated positively and strongly with both landscape heating and moisture, suggesting that autotrophic limitations other than water or heat controlled ultimate carbon accumulation on the wetland landscape. Because polar desert landscapes comprise the majority of land area in the high Arctic, changes in moisture, rather than heating, will likely continue to strongly affect future net carbon accumulation, at least until plant cover and soil quality changes substantially.

  19. Interhemispheric Differences in Dentifrication and Related Processes Affecting Polar Ozone

    NASA Technical Reports Server (NTRS)

    Santee, M. L.; Read, W. G.; Waters, J. W.; Froidevaux, L.; Manney, G. L.; Flower, D. A.; Jarnot, R. F.; Harwood, R. S.; Peckham, G. E.

    1994-01-01

    The severe depletion of stratospheric ozone over Antarctica in late winter and early spring is caused by enhanced CLO abundances arising from heterogeneous reactions on polar stratospheric clouds (PSCs). CLO abundances comparable to those over Antarctica have also been observed throughout the Arctic Vortex, but the accompanying loss of Arctic ozone has been much less severe.

  20. Lower Stratospheric Temperature Differences Between Meteorological Analyses in two cold Arctic Winters and their Impact on Polar Processing Studies

    NASA Technical Reports Server (NTRS)

    Manney, Gloria L.; Sabutis, Joseph L.; Pawson, Steven; Santee, Michelle L.; Naujokat, Barbara; Swinbank, Richard; Gelman, Melvyn E.; Ebisuzaki, Wesley; Atlas, Robert (Technical Monitor)

    2001-01-01

    A quantitative intercomparison of six meteorological analyses is presented for the cold 1999-2000 and 1995-1996 Arctic winters. The impacts of using different analyzed temperatures in calculations of polar stratospheric cloud (PSC) formation potential, and of different winds in idealized trajectory-based temperature histories, are substantial. The area with temperatures below a PSC formation threshold commonly varies by approximately 25% among the analyses, with differences of over 50% at some times/locations. Freie University at Berlin analyses are often colder than others at T is less than or approximately 205 K. Biases between analyses vary from year to year; in January 2000. U.K. Met Office analyses were coldest and National Centers for Environmental Prediction (NCEP) analyses warmest. while NCEP analyses were usually coldest in 1995-1996 and Met Office or NCEP[National Center for Atmospheric Research Reanalysis (REAN) warmest. European Centre for Medium Range Weather Forecasting (ECMWF) temperatures agreed better with other analyses in 1999-2000, after improvements in the assimilation model. than in 1995-1996. Case-studies of temperature histories show substantial differences using Met Office, NCEP, REAN and NASA Data Assimilation Office (DAO) analyses. In January 2000 (when a large cold region was centered in the polar vortex), qualitatively similar results were obtained for all analyses. However, in February 2000 (a much warmer period) and in January and February 1996 (comparably cold to January 2000 but with large cold regions near the polar vortex edge), distributions of "potential PSC lifetimes" and total time spent below a PSC formation threshold varied significantly among the analyses. Largest peaks in "PSC lifetime" distributions in January 2000 were at 4-6 and 11-14 days. while in the 1996 periods, they were at 1-3 days. Thus different meteorological conditions in comparably cold winters had a large impact on expectations for PSC formation and on the discrepancies between different meteorological analyses. Met Office. NCEP, REAN, ECMWF and DAO analyses are commonly used for trajectory calculations and in chemical transport models; the choice of which analysis to use can strongly influence the results of such studies.

  1. Ozone and aerosol changes during the 1991-1992 airborne Arctic stratospheric expedition

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Buller, Carolyn F.; Fenn, Marta A.; Grant, William B.; Ismail, Syed; Schoeberl, Mark R.; Toon, Owen B.; Loewenstein, Max; Podolske, James R.

    1993-01-01

    Stratospheric ozone and aerosol distributions were measured across the wintertime Arctic vortex from January to March 1992 with an airborne lidar system as part of the 1992 Airborne Arctic Stratospheric Expedition (AASE II). Aerosols from the Mount Pinatubo eruption were found outside and inside the vortex with distinctly different distributions that clearly identified the dynamics of the vortex. Changes in aerosols inside the vortex indicated advection of air from outside to inside the vortex below 16 kilometers. No polar stratospheric clouds were observed and no evidence was found for frozen volcanic aerosols inside the vortex. Between January and March, ozone depletion was observed inside the vortex from 14 to 20 kilometers with a maximum average loss of about 23 percent near 18 kilometers.

  2. Ozone and aerosol changes during the 1991-1992 Airborne Arctic Stratospheric Expedition

    SciTech Connect

    Browell, E.V.; Grant, W.B.; Ismail, S. ); Butler, C.F.; Fenn, M.A. ); Schoeberl, M.R. ); Toon, O.B.; Loewenstein, M.; Podolske, J.R. )

    1993-08-27

    Stratospheric ozone and aerosol distributions were measured across the wintertime Arctic vortex from January to March 1992 with an airborne lidar system as part of the 1992 Airborne Arctic Stratospheric Expedition (AASE II). Aerosols from the Mount Pinatubo eruption were found outside and inside the vortex with distinctly different distributions that clearly identified the dynamics of the vortex. Changes in aerosols inside the vortex indicated advection of air from outside to inside the vortex below 16 kilometers. No polar stratospheric clouds were observed and no evidence was found for frozen volcanic aerosols inside the vortex. Between January and March, ozone depletion was observed inside the vortex from 14 to 20 kilometers with a maximum average loss of about 23 percent near 18 kilometers.

  3. Visualization of vortex core polarity in NiFe nanodots by tilted Fresnel images.

    PubMed

    Ngo, Duc-The; McVitie, Stephen

    2011-07-01

    We illustrate an approach which allows determining the out-of-plane component of the vortex core (polarity) in NiFe nanodots using Fresnel imaging in Lorentz electron microscopy. Using tilted Fresnel images, contribution of the polarity is introduced into the Fresnel image. However, this contribution is relatively small and a difference image from two symmetrically tilted Fresnel images must be used to eliminate the strong contribution from the in-plane curling magnetization and non-magnetic contrast. The sense of the polarity appears as a bipolar white-black contrast in the difference image on the tilt axis. A vortex core with a diameter of 16.5 ± 2.5 nm is experimentally measured. Image tilting, displacement and geometrical distortion may disturb the difference image, and hence subtraction of the difference image must be aligned by cross-correlation. The method is also justified by a study of the observed contrast characteristic due to misalignment. The method is confirmed to be superior to similar approach with direct interpretation of information and more information subtracted. PMID:21864768

  4. Arctic Forecasts Available from Polar Bear Exhibit as an Example of Formal/Informal Collaboration

    NASA Astrophysics Data System (ADS)

    Landis, C. E.; Cervenec, J.

    2012-12-01

    A subset of the general population enjoys and frequents informal education venues, offering an opportunity for lifelong learning that also enhances and supports formal education efforts. The Byrd Polar Research Center (BPRC) at The Ohio State University collaborated with the Columbus Zoo & Aquarium (CZA) in the development of their Polar Frontier exhibit, from its initial planning to the Grand Opening of the exhibit, through the present. Of course, the addition to the Zoo of polar bears and Arctic fox in the Polar Frontier has been very popular, with almost a 7% increase in visitors in 2010 when the exhibit opened. The CZA and BPRC are now investigating ways to increase the climate literacy impact of the exhibit, and to increase engagement with the topics through follow-on activities. For example, individuals or classes anywhere in the world can check forecasts from the Polar Weather and Research Forecasting model and compare them to observed conditions-- allowing deep investigation into changes in the Arctic. In addition, opportunities exist to adapt the Zoo School experience (affecting several Central Ohio school districts) and/or to enable regular participation through social media such as Facebook, Twitter, and other forms of digital communication. BPRC's sustained engagement with the CZA is an example of a trusted and meaningful partnership where open dialogue exists about providing the best learning experience for visitors. This presentation will share some of the lessons learned from this unique partnership, and strategies that are adopted to move it forward.

  5. Different temperature adaptation in Arctic and Atlantic heterotrophic bacteria in the Barents Sea Polar Front region

    NASA Astrophysics Data System (ADS)

    Børsheim, Knut Yngve; Drinkwater, Kenneth F.

    2014-02-01

    In the northern Barents Sea, at and around the Polar Front, carbon cycle variables were investigated during 2 weeks in late summer of 2007. Arctic Water primary production in the experimental period averaged 50 mmol C m- 2 day- 1, as estimated from satellite sensed chlorophyll. In Atlantic waters, which appeared to just have passed the culmination of a late summer bloom, primary production was 125 mmol C m- 2 day- 1. Total organic carbon (TOC) averaged 82.4 ?M C in the mixed layer, and the values showed a gradient with highest values to the southeast and lowest to the northwest. The distribution of TOC was not related to the distribution of Atlantic and Arctic waters, although the highest values were found in Atlantic Water. Integrated bacterial production in the mixed layer, as estimated from thymidine incorporation rates, averaged 6.3% of primary production. In Atlantic Water, over the depth of the mixed layer, bacterial production rate averaged 0.40 mmol C m- 3 day- 1, which was 6.6 times the average in Arctic Water and 2.3 times the average in the front regions. Below 30 m depth, bacterial production rates were generally higher in the Arctic Water than in the Atlantic Water. Moreover, when production rates of bacteria were compared according to temperature, the rates in Arctic Water were systematically higher than the rates in Atlantic Water. This difference implies that the heterotrophic bacteria from the Arctic have adapted towards higher growth efficiency than the bacteria in Atlantic Water.

  6. The Arctic Human Health Initiative: a legacy of the International Polar Year 2007–2009

    PubMed Central

    Parkinson, Alan J.

    2013-01-01

    Background The International Polar Year (IPY) 2007–2008 represented a unique opportunity to further stimulate cooperation and coordination on Arctic health research and increase the awareness and visibility of Arctic regions. The Arctic Human Health Initiative (AHHI) was a US-led Arctic Council IPY coordinating project that aimed to build and expand on existing International Union for Circumpolar Health (IUCH) and Arctic Council human health interests. The project aimed to link researchers with potential international collaborators and to serve as a focal point for human health research, education, outreach and communication activities during the IPY. The progress of projects conducted as part of this initiative up until the end of the Arctic Council Swedish chairmanship in May 2013 is summarized in this report. Design The overall goals of the AHHI was to increase awareness and visibility of human health concerns of Arctic peoples, foster human health research, and promote health strategies that will improve health and well-being of all Arctic residents. Proposed activities to be recognized through the initiative included: expanding research networks that will enhance surveillance and monitoring of health issues of concern to Arctic peoples, and increase collaboration and coordination of human health research; fostering research that will examine the health impact of anthropogenic pollution, rapid modernization and economic development, climate variability, infectious and chronic diseases, intentional and unintentional injuries, promoting education, outreach and communication that will focus public and political attention on Arctic health issues, using a variety of publications, printed and electronic reports from scientific conferences, symposia and workshops targeting researchers, students, communities and policy makers; promoting the translation of research into health policy and community action including implementation of prevention strategies and health promotion; and promoting synergy and strategic direction of Arctic human health research and health promotion. Results As of 31 March, 2009, the official end of the IPY, AHHI represented a total of 38 proposals, including 21 individual Expressions of Intent (EoI), and 9 full proposals (FP), submitted to the IPY Joint Committee for review and approval from lead investigators from the US, Canada, Greenland, Norway, Finland, Sweden and the Russian Federation. In addition, there were 10 National Initiatives (NI-projects undertaken during IPY beyond the IPY Joint Committee review process). Individual project details can be viewed at www.arctichealth.org. The AHHI currently monitors the progress of 28 individual active human health projects in the following thematic areas: health network expansion (5 projects), infectious disease research (7 projects), environmental health research (7 projects), behavioral and mental health research (4 projects), and outreach education and communication (5 projects). Conclusions While some projects have been completed, others will continue well beyond the IPY. The IPY 2007–2008 represented a unique opportunity to further stimulate cooperation and coordination on Arctic health research and increase the awareness and visibility of Arctic regions. PMID:23971017

  7. Imaging polarimetry of the fogbow: polarization characteristics of white rainbows measured in the high Arctic.

    PubMed

    Horváth, Gábor; Hegedüs, Ramón; Barta, András; Farkas, Alexandra; Åkesson, Susanne

    2011-10-01

    The knowledge on the optics of fogbows is scarce, and their polarization characteristics have never been measured to our knowledge. To fill this gap we measured the polarization features of 16 fogbows during the Beringia 2005 Arctic polar research expedition by imaging polarimetry in the red, green and blue spectral ranges. We present here the first polarization patterns of the fogbow. In the patterns of the degree of linear polarization p, fogbows and their supernumerary bows are best visible in the red spectral range due to the least dilution of fogbow light by light scattered in air. In the patterns of the angle of polarization ? fogbows are practically not discernible because their ?-pattern is the same as that of the sky: the direction of polarization is perpendicular to the plane of scattering and is parallel to the arc of the bow, independently of the wavelength. Fogbows and their supernumeraries were best seen in the patterns of the polarized radiance. In these patterns the angular distance ? between the peaks of the primary and the first supernumerary and the angular width ? of the primary bow were determined along different radii from the center of the bow. ? ranged between 6.08° and 13.41°, while ? changed from 5.25° to 19.47°. Certain fogbows were relatively homogeneous, meaning small variations of ? and ? along their bows. Other fogbows were heterogeneous, possessing quite variable ?- and ?-values along their bows. This variability could be a consequence of the characteristics of the high Arctic with open waters within the ice shield resulting in the spatiotemporal change of the droplet size within the fog. PMID:22016248

  8. Observational constraints on the tropospheric and near-surface winter signature of the Northern Hemisphere stratospheric polar vortex

    NASA Astrophysics Data System (ADS)

    Graf, Hans-F.; Zanchettin, Davide; Timmreck, Claudia; Bittner, Matthias

    2014-12-01

    A composite analysis of Northern Hemisphere's mid-winter tropospheric anomalies under the conditions of strong and weak stratospheric polar vortex was performed on NCEP/NCAR reanalysis data from 1948 to 2013 considering, as additional grouping criteria, the coincidental states of major seasonally relevant climate phenomena, such as El Niño-Southern Oscillation (ENSO), Quasi Biennial Oscillation and strong volcanic eruptions. The analysis reveals that samples of strong polar vortex nearly exclusively occur during cold ENSO states, while a weak polar vortex is observed for both cold and warm ENSO. The strongest tropospheric and near-surface anomalies are found for warm ENSO and weak polar vortex conditions, suggesting that internal tropospheric circulation anomalies related to warm ENSO constructively superpose on dynamical effects from the stratosphere. Additionally, substantial differences are found between the continental winter warming patterns under strong polar vortex conditions in volcanically-disturbed and volcanically-undisturbed winters. However, the small-size samples obtained from the multi-compositing prevent conclusive statements about typical patterns, dominating effects and mechanisms of stratosphere-troposphere interaction on the seasonal time scale based on observational/reanalysis data alone. Hence, our analysis demonstrates that patterns derived from observational/reanalysis time series need to be taken with caution as they not always provide sufficiently robust constraints to the inferred mechanisms implicated with stratospheric polar vortex variability and its tropospheric and near-surface signature. Notwithstanding this argument, we propose a limited set of mechanisms that together may explain a relevant part of observed climate variability. These may serve to define future numerical model experiments minimizing the sample biases and, thus, improving process understanding.

  9. Detrital zircons of deep-sea sediments of the Arctic ocean - key to the understanding of High Polar Arctic tectonics

    NASA Astrophysics Data System (ADS)

    Shokalsky, S.; Morozov, A.; Petrov, O.; Belyatsky, B.; Rekant, P.; Shevchenko, S.; Sergeev, S.

    2012-04-01

    Zircons from sedimentary rocks bear the information on composition of vast territories often inaccessible for geologic investigation but which are the source of material. The studies of modern beaches and fluvial deposits demonstrate the efficiency of reconstruction of composition and distribution of rock types based on clastic zircon characteristics (Zircon, 2003). We have studied nine 0,5 kg specimens (every meter) from gravity-corer sample of deep sea-bottom sedimentary cover within the Geophysicists Spur region (Lomonosov Ridge) which represent first 9 meters of the section formed during 70 000 years. Heavy fraction is composed by garnet, tourmaline, titanite, rutile and by 200-300 grains of zircon per sample. Zircons in all samples are different in morphology and inner structure: from faceted needle-like to perfectly rounded, from colorless to brown opaque, with thin growth zones and inherited cores, as well as homogeneous. U-Pb SIMS SHRIMP isotope dating (50 grain analyses for each sample) was applied to two key specimens from the depth of 12-14 and 505-507 cm. The age probability distribution diagrams show that the main age peaks are of 138-147, 200-300, 400-800 and 1845-2000 Ma; few grains of 2700 Ma and one grain is 3000 Ma old. Our previous data for the zircon age distribution for box-corer sample of hemipelagic sediment from the North Pole (Grikurov et al., 2011) revealed peaks of 160, 200-450 (max 260-300 Ma), 800, 1855, 2000 and 2600 Ma. Zircons from three samples above show common features: 1) presence of Archean grains (>2400 Ma), 2) defined age peak of 1800-2000 Ma (ca 30% of grains), 3) lack of Grenvillian age zircons, 4) youngest ages of 40-160 Ma. Thus, all three studied samples have very similar provenance source, the deposition time of sandstones, from which had mainly formed the modern (<30 000 years) sediments, is Jurassic (?140-160 Ma). About 50% of analyzed zircons falls to the age interval 200-500 Ma. However, grains distribution is appreciably different for Polar sample (200-450 Ma) and Geophysicists Spur (200, 300, 400-600 Ma). It is known, that formation of modern deep-sea sediments takes place mainly due to fluvial discharge (ca 90%), erosion of oceanic bedrocks and coastal beaches. Wind-borne component and extraterraneous dust are not significant (<1%). Transportation of continental material by icebergs (ice-rafted debris) is added to these sources in polar areas. Well-known Permian-Triassic sandstones of Arctic coast (including polar islands) are defined by the presence of Grenvillian age zircons - Canadian Arctic, Alaska, Greenland (Miller et al., 2006), while Jurassic-Cretaceous sandstones of the South Anjui Zone, Chukotka and New Siberian Islands of Russian Arctic (Miller et al., 2008) have clastic zircon with ages very similar to the obtained by us for deep-sea sediments. We suppose that modern deep-sea sediments were formed either due to ablation of these sandstones with distal transportation of detritus (highly unlikely), or due to weathering of similar rock of oceanic highs of Lomonosov Ridge. The last is more realistic because the similarity of the Lomonosov Ridge and north-east continental Arctic is proved by geophysical data (Jokat et al., 1992).

  10. Vulnerability of polar oceans to anthropogenic acidification: comparison of arctic and antarctic seasonal cycles.

    PubMed

    Shadwick, E H; Trull, T W; Thomas, H; Gibson, J A E

    2013-01-01

    Polar oceans are chemically sensitive to anthropogenic acidification due to their relatively low alkalinity and correspondingly weak carbonate buffering capacity. Here, we compare unique CO2 system observations covering complete annual cycles at an Arctic (Amundsen Gulf) and Antarctic site (Prydz Bay). The Arctic site experiences greater seasonal warming (10 vs 3°C), and freshening (3 vs 2), has lower alkalinity (2220 vs 2320 ?mol/kg), and lower summer pH (8.15 vs 8.5), than the Antarctic site. Despite a larger uptake of inorganic carbon by summer photosynthesis, the Arctic carbon system exhibits smaller seasonal changes than the more alkaline Antarctic system. In addition, the excess surface nutrients in the Antarctic may allow mitigation of acidification, via CO2 removal by enhanced summer production driven by iron inputs from glacial and sea-ice melting. These differences suggest that the Arctic system is more vulnerable to anthropogenic change due to lower alkalinity, enhanced warming, and nutrient limitation. PMID:23903871

  11. Saturn's North Polar Vortex Revealed by Cassini/VIMS: Zonal Wind Structure and Constraints on Cloud Distributions

    NASA Astrophysics Data System (ADS)

    Baines, Kevin H.; Momary, T. W.; Fletcher, L. N.; Buratti, B. J.; Roos-Serote, M.; Showman, A. P.; Brown, R. H.; Clark, R. N.; Nicholson, P. D.

    2008-09-01

    We present the first high-spatial resolution, near-nadir imagery and movies of Saturn's north polar region that reveal the wind structure of a north polar vortex. Obtained by Cassini/VIMS on June 15, 2008 from high over Saturn's polar region (sub-spacecraft latitude of 65 degrees N. lat) at an altitude of 0.42 million km during the long polar night, these 210-per-pixel images of the polar region north of 73 degrees N. latitude show several concentric cloud rings and hundreds of individual cloud features in silhouette against the 5-micron background thermal glow of Saturn's deep atmosphere. In contrast to the clear eye of the south polar vortex, the north polar vortex sports a central cloud feature about 650-km in diameter. Zonal winds reach a maximum of 150 m/s near 88 degrees N. latitude (planetocentric) - comparable to the south polar vortex maximum of 190 m/s near 88 degrees S. latitude - and fall off nearly monotonically to 10 m/s near 80 degrees N. latitude. At slightly greater distance from the pole, inside the north polar hexagon in the 75-77 degree N. latitude region, zonal winds increase dramatically to 130 m/s, as silhouetted clouds are seen speeding aroud the "race track” of the hexagonal feature. VIMS 5-micron thermal observations over a 1.6-year period from October 29, 2006 to June 15, 2008 are consistent with the polar hexagon structure itself remaining fixed in the Voyager-era radio rotation rate (Desch and Kaiser, Geophys. Res. Lett, 8, 253-256, 1981) to within an accuracy of 3 seconds per rotational period. This agrees with the stationary nature of the wave in this rotation system found by Godfrey (Icarus 76, 335-356, 1988), but is inconsistent with rotation rates found during the current Cassini era.

  12. Unexpected Levels of Biological Activity during the Polar Night Offer New Perspectives on a Warming Arctic.

    PubMed

    Berge, Jørgen; Daase, Malin; Renaud, Paul E; Ambrose, William G; Darnis, Gerald; Last, Kim S; Leu, Eva; Cohen, Jonathan H; Johnsen, Geir; Moline, Mark A; Cottier, Finlo; Varpe, Øystein; Shunatova, Natalia; Ba?azy, Piotr; Morata, Nathalie; Massabuau, Jean-Charles; Falk-Petersen, Stig; Kosobokova, Ksenia; Hoppe, Clara J M; W?s?awski, Jan Marcin; Kukli?ski, Piotr; Lege?y?ska, Joanna; Nikishina, Daria; Cusa, Marine; K?dra, Monika; W?odarska-Kowalczuk, Maria; Vogedes, Daniel; Camus, Lionel; Tran, Damien; Michaud, Emma; Gabrielsen, Tove M; Granovitch, Andrei; Gonchar, Anya; Krapp, Rupert; Callesen, Trine A

    2015-10-01

    The current understanding of Arctic ecosystems is deeply rooted in the classical view of a bottom-up controlled system with strong physical forcing and seasonality in primary-production regimes. Consequently, the Arctic polar night is commonly disregarded as a time of year when biological activities are reduced to a minimum due to a reduced food supply. Here, based upon a multidisciplinary ecosystem-scale study from the polar night at 79°N, we present an entirely different view. Instead of an ecosystem that has entered a resting state, we document a system with high activity levels and biological interactions across most trophic levels. In some habitats, biological diversity and presence of juvenile stages were elevated in winter months compared to the more productive and sunlit periods. Ultimately, our results suggest a different perspective regarding ecosystem function that will be of importance for future environmental management and decision making, especially at a time when Arctic regions are experiencing accelerated environmental change [1]. PMID:26412132

  13. Chinese Journal of Polar Science, Vol. 19,No. 2,159 -167, December 2008 Modeling Arctic Ocean heat transport and warming episodes in

    E-print Network

    Chinese Journal of Polar Science, Vol. 19,No. 2,159 -167, December 2008 Modeling Arctic Ocean heat and Hydrological Institute, Sweden Received September 20, 2008 Abstract This study investigates the Arctic Ocean temperature (AWCT) in the Arctic Ocean and shows that four largest decadal- scale warming episodes occurred

  14. Polar vortex formation in giant-planet atmospheres due to moist convection

    NASA Astrophysics Data System (ADS)

    O'Neill, Morgan E.; Emanuel, Kerry A.; Flierl, Glenn R.

    2015-07-01

    A strong cyclonic vortex has been observed on each of Saturn’s poles, coincident with a local maximum in observed tropospheric temperature. Neptune also exhibits a relatively warm, although much more transient, region on its south pole. Whether similar features exist on Jupiter will be resolved by the 2016 Juno mission. Energetic, small-scale storm-like features that originate from the water-cloud level or lower have been observed on each of the giant planets and attributed to moist convection, suggesting that these storms play a significant role in global heat transfer from the hot interior to space. Nevertheless, the creation and maintenance of Saturn’s polar vortices, and their presence or absence on the other giant planets, are not understood. Here we use simulations with a shallow-water model to show that storm generation, driven by moist convection, can create a strong polar cyclone throughout the depth of a planet’s troposphere. We find that the type of shallow polar flow that occurs on a giant planet can be described by the size ratio of small eddies to the planetary radius and the energy density of its atmosphere due to latent heating from moist convection. We suggest that the observed difference in these parameters between Saturn and Jupiter may preclude a Jovian polar cyclone.

  15. The International Arctic Buoy Programme (IABP) - An International Polar Year Every Year

    NASA Astrophysics Data System (ADS)

    Hanna, M.; Rigor, I.; Ortmeyer, M.; Haas, C.

    2004-12-01

    A network of automatic data buoys to monitor synoptic-scale fields of sea level pressure (SLP), surface air temperature (SAT), and ice motion throughout the Arctic Ocean was recommended by the U.S. National Academy of Sciences in 1974. Based on the Academy's recommendation, the Arctic Ocean Buoy Program was established by the Polar Science Center, Applied Physics Laboratory (APL), University of Washington, in 1978 to support the Global Weather Experiment. Operations began in early 1979, and the program continued through 1990 under funding from various agencies. In 1991, the International Arctic Buoy Programme (IABP) succeeded the Arctic Ocean Buoy Program, but the basic objective remains - to maintain a network of drifting buoys on the Arctic Ocean to provide meteorological and oceanographic data for real-time operational requirements and research purposes including support to the World Climate Research Programme and the World Weather Watch Programme. The IABP currently has 37 buoys deployed on the Arctic Ocean. Most of the buoys measure SLP and SAT, but many buoys are enhanced to measure other geophysical variables such as sea ice thickness, ocean temperature and salinity. This observational array is maintained by the 20 Participants from 10 different countries, who support the program through contributions of buoys, deployment logistics, and other services. The observations from the IABP are posted on the Global Telecommunications System for operational use, are archived at the World Data Center for Glaciology at the National Snow and Ice Data Center (http://nsidc.org), and can also be obtained from the IABP web server for research (http://iabp.apl.washington.edu). The observations from the IABP have been essential for: 1.) Monitoring Arctic and global climate change; 2.) Forecasting weather and sea ice conditions; 3.) Forcing, assimilation and validation of global weather and climate models; 4.) Validation of satellite data; etc. As of 2003, over 450 papers have been written using the observations collected by the IABP. The observations from IABP have been one of the cornerstones for environmental forecasting and studies of climate and climate change, i.e. many of the changes in Arctic climate were first observed or explained using data from the IABP. The IABP is also evolving to better support the operational and research requirements of the community. For example, some of the Participants of the IABP have been deploying buoys which not only measure SLP and SAT, but also ocean currents, temperatures and salinity. Other buoys have been enhanced to measure the ice mass balance (IMB) using thermistor strings and pingers aimed at the top and bottom of the sea ice. Some of these ocean and IMB buoys are deployed in close proximity to each other in order to provide a myriad of concurrent observations at a few points across the Arctic Ocean. From these data we can also estimate time variations in other geophysical variables such as oceanic heat storage and heat flux. These stations provide critical atmospheric, ice, and upper ocean hydrographic measurements that cannot be obtained by other means. The Arctic and global climate system is changing. These changes threaten our native cultures and ecosystems, but may also provide economic and social opportunities. In order to understand and respond to these changes, we need to sustain our current observational systems, and for the Arctic, the IABP provides the longest continuing record of observations.

  16. Arctic (and Antarctic) Observing Experiment - an Assessment of Methods to Measure Temperature over Polar Environments

    NASA Astrophysics Data System (ADS)

    Rigor, I. G.; Clemente-Colon, P.; Nghiem, S. V.; Hall, D. K.; Woods, J. E.; Henderson, G. R.; Zook, J.; Marshall, C.; Gallage, C.

    2014-12-01

    The Arctic environment has been undergoing profound changes; the most visible is the dramatic decrease in Arctic sea ice extent (SIE). These changes pose a challenge to our ability to measure surface temperature across the Polar Regions. Traditionally, the International Arctic Buoy Programme (IABP) and International Programme for Antarctic Buoys (IPAB) have measured surface air temperature (SAT) at 2-m height, which minimizes the ambiguity of measurements near of the surface. Specifically, is the temperature sensor measuring open water, snow, sea ice, or air? But now, with the dramatic decrease in Arctic SIE, increase in open water during summer, and the frailty of the younger sea ice pack, the IABP has had to deploy and develop new instruments to measure temperature. These instruments include Surface Velocity Program (SVP) buoys, which are commonly deployed on the world's ice-free oceans and typically measure sea surface temperature (SST), and the new robust Airborne eXpendable Ice Beacons (AXIB), which measure both SST and SAT. "Best Practice" requires that these instruments are inter-compared, and early results showing differences in collocated temperature measurements of over 2°C prompted the establishment of the IABP Arctic Observing Experiment (AOX) buoy test site at the US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) site in Barrow, Alaska. Preliminary results showed that the color of the hull of SVP buoys introduces a bias due to solar heating of the buoy. Since then, we have recommended that buoys should be painted white to reduce biases in temperature measurements due to different colors of the buoys deployed in different regions of the Arctic or the Antarctic. Measurements of SAT are more robust, but some of the temperature shields are susceptible to frosting. During our presentation we will provide an intercomparison of the temperature measurements at the AOX test site (i.e. high quality DOE/ARM observations compared with unattended buoy measurements, and satellite retrievals). We will also show how these data may be used to improve our record of temperature over polar environments.

  17. Interhemispheric comparison of the development of the stratospheric polar vortex during fall: A 3-dimensional perspective for 1991-1992

    SciTech Connect

    Manney, G.L.; Zurek, R.W. )

    1993-06-18

    The authors present the results of detailed studies of the northern and southern polar vortex development during 1991/1992, recreated from National Meteorological Center data. In general the data shows that in the southern hemisphere, the polar vortex developed with less short term variations, deepened very rapidly, and continued to grow well into the winter. Temperatures in the southern hemisphere would support the formation of polar stratospheric clouds for greater periods of time, and over larger areas than in the north. These results are compared to observations of ClO from the microwave limb sounder on the upper atmosphere research satellite. They lend support to the hemispherical differences observed in ClO by this probe, under the present model of reactive chlorine formation on polar stratospheric cloud particles.

  18. The impact of volcanic aerosol on the Northern Hemisphere stratospheric polar vortex: mechanisms and sensitivity to forcing structure

    NASA Astrophysics Data System (ADS)

    Toohey, M.; Krüger, K.; Bittner, M.; Timmreck, C.; Schmidt, H.

    2014-12-01

    Observations and simple theoretical arguments suggest that the Northern Hemisphere (NH) stratospheric polar vortex is stronger in winters following major volcanic eruptions. However, recent studies show that climate models forced by prescribed volcanic aerosol fields fail to reproduce this effect. We investigate the impact of volcanic aerosol forcing on stratospheric dynamics, including the strength of the NH polar vortex, in ensemble simulations with the Max Planck Institute Earth System Model. The model is forced by four different prescribed forcing sets representing the radiative properties of stratospheric aerosol following the 1991 eruption of Mt. Pinatubo: two forcing sets are based on observations, and are commonly used in climate model simulations, and two forcing sets are constructed based on coupled aerosol-climate model simulations. For all forcings, we find that simulated temperature and zonal wind anomalies in the NH high latitudes are not directly impacted by anomalous volcanic aerosol heating. Instead, high-latitude effects result from enhancements in stratospheric residual circulation, which in turn result, at least in part, from enhanced stratospheric wave activity. High-latitude effects are therefore much less robust than would be expected if they were the direct result of aerosol heating. Both observation-based forcing sets result in insignificant changes in vortex strength. For the model-based forcing sets, the vortex response is found to be sensitive to the structure of the forcing, with one forcing set leading to significant strengthening of the polar vortex in rough agreement with observation-based expectations. Differences in the dynamical response to the forcing sets imply that reproducing the polar vortex responses to past eruptions, or predicting the response to future eruptions, depends on accurate representation of the space-time structure of the volcanic aerosol forcing.

  19. Analysis of UARS data in the Southern Polar Vortex n September, 1992 Using a Chemical Transport Model

    NASA Technical Reports Server (NTRS)

    Chipperfield, M. P.; Santee, M. L.; Froidevaux, L.; Manney, G. L.; Read, W. G.; Waters, J. W.; Roche, A. E.; Russel, J. M.

    1996-01-01

    We have used a new, isentropic-coordinate three-dimensional chemical transport model to investigate the decay of C1O and evolution of other species in the Antarctic polar vortex during September, 1992. The model simulations cover the same southern hemisphere period studied in a companion data paper by Santee et al.

  20. Arctic Observing Experiment - An Assessment of Instruments Used to Monitor the Polar Environments

    NASA Astrophysics Data System (ADS)

    Rigor, I. G.; Johnson, J.; Clemente-Colon, P.; Nghiem, S. V.; Hall, D. K.; Woods, J. E.; Valentic, T. A.; Henderson, G. R.; Marshall, C.; Gallage, C.; Zook, J.; Davis, Z.

    2014-12-01

    To understand and predict weather and climate require an accurate observing network that measures the fundamental meteorological parameters: temperature, air pressure, and wind. Measuring these parameters autonomously in the polar regions is especially challenging. To assess the accuracy of polar measurement networks, we established the Arctic Observing Experiment (AOX) test site in March 2013 at the Department of Energy (DOE) Atmospheric Radiation and Meteorology (ARM) site in Barrow, Alaska. We deployed a myriad of data loggers and autonomous buoys, which represent most of the instruments that are commonly deployed by the International Arctic Buoy Programme (IABP) to measure temperature, air pressure and wind. Estimates of temperature over this area have also been analyzed from satellites (e.g., using the Moderate-resolution Imaging Spectroradiometer (MODIS) ice-surface temperature (IST)) product, and can complement data from in-situ sensors and provide consistent measurements under clear-sky conditions. Preliminary results reveal that some of the buoys are susceptible to solar heating, icing can block barometers for short periods, and frosting may insulate air temperature sensors and freeze-lock anemometers. Some of these issues may be addressed by simply painting the buoys white to reduce solar heating of the buoys, and using better temperature shields and barometer ports. Nevertheless, frosting of ultrasonic and mechanical anemometers remains a significant challenge. These results will be useful to initiate a protocol to obtain accurate and consistent measurements from the IABP, the Arctic Observing Network (AON), the International Program for Antarctic Buoys, and the Southern Ocean Observing System to monitor polar environments.

  1. Polar Vortex Conditions during the 1995-96 Artic Winter: Meteorology and MLS Ozone

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Santee, M. L.; Froidevaux, L.; Waters, J. W.; Zurek, R. W.

    1996-01-01

    The 1995-96 northern hemisphere (NH) 205 winter stratosphere was colder than in any of the previous 17 winters, with lower stratospheric temperatures continuously below the type 1 (primarily HN03) polar stratospheric cloud (PSC) threshold for over 2 1/2 months. Upper tropospheric ridges in late Feb and early Mar 1996 led to the lowest observed NH lower stratospheric temperatures, and the latest observed NH temperatures below the type 2 (water ice) PSC threshold. Consistent with the unusual cold and chemical processing on PSCS, Upper Atmosphere Research Satellite (UARS) MLS observed a greater decrease in lower stratospheric ozone (03) in 1995-96 than in any of the previous 4 NH winters. 03 decreased throughout the vortex over an altitude range nearly as large as that typical of the southern hemisphere (SH). The decrease between late Dec 1995 and early Mar 1996 was about 2/3 of that over the equivalent SH period. As in other NH winters, temperatures in 1996 rose above the PSC threshold before the spring equinox, ending chemical processing in the NH vortex much earlier than is usual in the SH. A downward trend in column 03 above 100 hPa during Jan and Feb 1996 appears to be related to the lower stratospheric 03 depletion.

  2. Arctic and Antarctic exploration including the contributions of physicians and effects of disease in the polar regions.

    PubMed

    Fodstad, H; Kondziolka, D; Brophy, B P; Roberts, D W; Girvin, J P

    1999-05-01

    A history of Arctic and Antarctic exploration, whether to find a Northwest Passage, North Pole, or South Pole, is a story of triumph and tribulation. The hardship experienced by polar explorers in the last 1000 years permeates the tales of achievement. Physicians and surgeons have played prominent roles in all major polar explorations. No significant Arctic voyage, particularly in the last 300 years, was made without a member of the party trained in the management of medical emergencies and in basic surgery. During times of health, surgeons functioned as the voyage naturalists with expertise in biology, botany, zoology, and the writing of scientific catalogs. Spurred by our interest and fascination with the history of polar exploration, we reviewed the roles of physicians and natural scientists in Arctic and Antarctic adventures. PMID:10232525

  3. Geographical distribution of organochlorine pesticides (OCPs) in polar bears (Ursus maritimus) in the Norwegian and Russian Arctic

    USGS Publications Warehouse

    Lie, E.; Bernhoft, A.; Riget, F.; Belikov, Stanislav; Boltunov, Andrei N.; Derocher, A.E.; Garner, G.W.; Wiig, O.; Skaare, J.U.

    2003-01-01

    Geographical variation of organochlorine pesticides (OCPs) was studied in blood samples from 90 adult female polar bear (Ursus maritimus) from Svalbard, Franz Josef Land, Kara Sea, East-Siberian Sea and Chukchi Sea. In all regions, oxychlordane was the dominant OCP. Regional differences in mean levels of HCB, oxychlordane, trans-nonachlor, ??-HCH, ??-HCH and p,p???-DDE were found. The highest levels of oxychlordane, trans-nonachlor and DDE were found in polar bears from Franz Josef Land and Kara Sea. HCB level was lowest in polar bears from Svalbard. Polar bears from Chukchi Sea had the highest level of ??- and ??-HCH. The lowest ??-HCH concentration was found in bears from Kara Sea. In all the bears, ???HCHs was dominated by ??-HCH. The geographical variation in OCP levels and pattern may suggest regional differences in pollution sources and different feeding habits in the different regions. Polar bears from the Western Russian Arctic were exposed to higher levels of chlordanes and p,p???-DDE than polar bears from locations westwards and eastwards from this region. This may imply the presence of a significant pollution source in the Russian Arctic area. The study suggests that the western Russian Arctic is the most contaminated region of the Arctic and warrants further research. ?? 2002 Elsevier Science B.V. All rights reserved.

  4. Vortex Rotation in a Nb Thin Film: A Spin-Polarized Neutron Reflectivity and Magnetization Study

    NASA Astrophysics Data System (ADS)

    Miceli, P. F.; Han, S.-W.; Farmer, J.; Kaiser, H.; Roshchin, I. R.; Greene, L. H.

    2000-03-01

    Spin-polarized neutron reflectivity (SPNR) and DC magnetization measurements are quantitatively compared for the magnetic field applied parallel to the plane of a 1370Åthick Nb film. Recently, it was shown that vortices could be detected by SPNR [1] and that the magnetization parallel to the film plane could be obtained. ([1] S.-W. Han et. al., Phys. Rev. B 59, 14692 (1999)) For the Nb film, SPNR shows reversible behavior whereas the DC magnetization shows substantial hysteresis. The difference is explained by demagnetization effects combined with a rotation of the vortex magnetic field out of the film plane as the applied field is reduced. It is also shown that by combining the two techniques, one can distinguish the parallel and perpendicular components of magnetization.

  5. Identifying polar bear resource selection patterns to inform offshore development in a dynamic and changing Arctic

    USGS Publications Warehouse

    Wilson, Ryan R.; Horne, Jon S.; Rode, Karyn D.; Regehr, Eric V.; Durner, George M.

    2014-01-01

    Although sea ice loss is the primary threat to polar bears (Ursus maritimus), little can be done to mitigate its effects without global efforts to reduce greenhouse gas emissions. Other factors, however, could exacerbate the impacts of sea ice loss on polar bears, such as exposure to increased industrial activity. The Arctic Ocean has enormous oil and gas potential, and its development is expected to increase in the coming decades. Estimates of polar bear resource selection will inform managers how bears use areas slated for oil development and to help guide conservation planning. We estimated temporally-varying resource selection patterns for non-denning adult female polar bears in the Chukchi Sea population (2008–2012) at two scales (i.e., home range and weekly steps) to identify factors predictive of polar bear use throughout the year, before any offshore development. From the best models at each scale, we estimated scale-integrated resource selection functions to predict polar bear space use across the population's range and determined when bears were most likely to use the region where offshore oil and gas development in the United States is slated to occur. Polar bears exhibited significant intra-annual variation in selection patterns at both scales but the strength and annual patterns of selection differed between scales for most variables. Bears were most likely to use the offshore oil and gas planning area during ice retreat and growth with the highest predicted use occurring in the southern portion of the planning area. The average proportion of predicted high-value habitat in the planning area was >15% of the total high-value habitat for the population during sea ice retreat and growth and reached a high of 50% during November 2010. Our results provide a baseline on which to judge future changes to non-denning adult female polar bear resource selection in the Chukchi Sea and help guide offshore development in the region. Lastly, our study provides a framework for assessing potential impacts of offshore oil and gas development to other polar bear populations around the Arctic.

  6. Is Ambient Light during the High Arctic Polar Night Sufficient to Act as a Visual Cue for Zooplankton?

    PubMed Central

    Cohen, Jonathan H.; Berge, Jørgen; Moline, Mark A.; Sørensen, Asgeir J.; Last, Kim; Falk-Petersen, Stig; Renaud, Paul E.; Leu, Eva S.; Grenvald, Julie; Cottier, Finlo; Cronin, Heather; Menze, Sebastian; Norgren, Petter; Varpe, Øystein; Daase, Malin; Darnis, Gerald; Johnsen, Geir

    2015-01-01

    The light regime is an ecologically important factor in pelagic habitats, influencing a range of biological processes. However, the availability and importance of light to these processes in high Arctic zooplankton communities during periods of 'complete' darkness (polar night) are poorly studied. Here we characterized the ambient light regime throughout the diel cycle during the high Arctic polar night, and ask whether visual systems of Arctic zooplankton can detect the low levels of irradiance available at this time. To this end, light measurements with a purpose-built irradiance sensor and coupled all-sky digital photographs were used to characterize diel skylight irradiance patterns over 24 hours at 79°N in January 2014 and 2015. Subsequent skylight spectral irradiance and in-water optical property measurements were used to model the underwater light field as a function of depth, which was then weighted by the electrophysiologically determined visual spectral sensitivity of a dominant high Arctic zooplankter, Thysanoessa inermis. Irradiance in air ranged between 1–1.5 x 10-5 ?mol photons m-2 s-1 (400–700 nm) in clear weather conditions at noon and with the moon below the horizon, hence values reflect only solar illumination. Radiative transfer modelling generated underwater light fields with peak transmission at blue-green wavelengths, with a 465 nm transmission maximum in shallow water shifting to 485 nm with depth. To the eye of a zooplankter, light from the surface to 75 m exhibits a maximum at 485 nm, with longer wavelengths (>600 nm) being of little visual significance. Our data are the first quantitative characterisation, including absolute intensities, spectral composition and photoperiod of biologically relevant solar ambient light in the high Arctic during the polar night, and indicate that some species of Arctic zooplankton are able to detect and utilize ambient light down to 20–30m depth during the Arctic polar night. PMID:26039111

  7. Is Ambient Light during the High Arctic Polar Night Sufficient to Act as a Visual Cue for Zooplankton?

    PubMed

    Cohen, Jonathan H; Berge, Jørgen; Moline, Mark A; Sørensen, Asgeir J; Last, Kim; Falk-Petersen, Stig; Renaud, Paul E; Leu, Eva S; Grenvald, Julie; Cottier, Finlo; Cronin, Heather; Menze, Sebastian; Norgren, Petter; Varpe, Øystein; Daase, Malin; Darnis, Gerald; Johnsen, Geir

    2015-01-01

    The light regime is an ecologically important factor in pelagic habitats, influencing a range of biological processes. However, the availability and importance of light to these processes in high Arctic zooplankton communities during periods of 'complete' darkness (polar night) are poorly studied. Here we characterized the ambient light regime throughout the diel cycle during the high Arctic polar night, and ask whether visual systems of Arctic zooplankton can detect the low levels of irradiance available at this time. To this end, light measurements with a purpose-built irradiance sensor and coupled all-sky digital photographs were used to characterize diel skylight irradiance patterns over 24 hours at 79°N in January 2014 and 2015. Subsequent skylight spectral irradiance and in-water optical property measurements were used to model the underwater light field as a function of depth, which was then weighted by the electrophysiologically determined visual spectral sensitivity of a dominant high Arctic zooplankter, Thysanoessa inermis. Irradiance in air ranged between 1-1.5 x 10-5 ?mol photons m-2 s-1 (400-700 nm) in clear weather conditions at noon and with the moon below the horizon, hence values reflect only solar illumination. Radiative transfer modelling generated underwater light fields with peak transmission at blue-green wavelengths, with a 465 nm transmission maximum in shallow water shifting to 485 nm with depth. To the eye of a zooplankter, light from the surface to 75 m exhibits a maximum at 485 nm, with longer wavelengths (>600 nm) being of little visual significance. Our data are the first quantitative characterisation, including absolute intensities, spectral composition and photoperiod of biologically relevant solar ambient light in the high Arctic during the polar night, and indicate that some species of Arctic zooplankton are able to detect and utilize ambient light down to 20-30m depth during the Arctic polar night. PMID:26039111

  8. Polar Gateways Arctic Circle Sunrise 2008 Conference at the Top of the World

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Kauristie, Kirsti; Weatherwax, Allan T.; Sandahl, Ingrid; Ostgaard, Nikolai; Sheehan, Glenn W.; Smith, Roger W.; Lewis, Elaine M.; Cline, Troy D.; Haines-Stiles, Geoff

    2008-01-01

    The Polar Gateways conference was hosted during January 23-29, 2008, the first week of polar sunrise at Barrow, Alaska, at the new Barrow Arctic Research Center of the Barrow Arctic Science consortium (BASC). The dawn week of polar day, the highly variable low temperatures, and the ice-covered shore tundra and adjacent sea ice conditions provided an appropriate locale for a conference dedicated in the spirit of the International Polar and Heliophysical Years 2007-2009 to the educational exploration of polar and icy world science of Earth and the solar system. The many scientific, educational, and cultural interactions with the local community of four thousand residents, sixty percent native Inupiat Eskimo, further provided an unforgettable experience of what life might be someday be like on other remote polar and icy worlds to be explored and eventually inhabited. Over one hundred active participants, more than half participating remotely, contributed science presentations and educational activities during this unique circumpolar and very "green" conference. Most remote contributions came via videoconference from the Swedish Institute of Space Physics (IRF) at Kisuna, Sweden, the EISCAT Svalbard Radar Facility at Spitzbergen, Norway, the University of Alaska at Fairbanks, NASA Goddard Space Flight Center and the Jet Propulsion Laboratory, the University of California at Berkeley, and the University of Arizona. A few contributors participated via teleconference, including one from the Polar Geophysical Institute at Apatity in Russia. These active contributions spanned up to thirteen time zones (Alaska to Russia) at various tirnes during the conference. Primary videoconferencing support between Barrow and other sites was ably provided by the University of Alaska at Fairbanks, and local operators at each remote site collectively made this conference possible. Science presentations spanned the solar system from the polar Sun and heliospheric environment to Earth, Moon, Mars, Jupiter, Saturn, the Kuiper Belt, and the solar wind termination shock now crossed by both Voyager spacecraft. Barrow participants experienced look and feel of icy worlds like Europa by going "on the ice" during snowmobile expeditions to the near-shore sea ice and Point Barrow. Extensive educational outreach activities were conducted with the local Barrow township and North Slope Borough communities, partly through several interviews with local host Earl Finkler on Barrow's KBRW Radio, and through the NASA Digital Learning Network (DLN) "live from the top of the world" at Barrow. The Goddard robotic rover "Nunuq of the North" became a local celebrity. The complete science program and photo library, eventually also including video recordings of all main presentations, will be available at the new polargateways2008.gsfc.nasa.gov web site (old version: polargateways2008.org) with links to educational materials from the conference already accessible at sunearthday.nasa.gov/polarsunrise.

  9. Polar Gateways Arctic Circle Sunrise 2008 Conference at the Top of the World

    NASA Astrophysics Data System (ADS)

    Cooper, J. F.; Kauristie, K.; Weatherwax, A. T.; Sheehan, G. W.; Smith, R. W.; Cline, T. D.; Lewis, E. M.; Haines-Stiles, G.

    2008-12-01

    The Polar Gateways conference was hosted during January 23-29, 2008, the first week of polar sunrise at Barrow, Alaska, at the new Barrow Arctic Research Center of the Barrow Arctic Science Consortium (BASC). The dawn week of polar day, the highly variable low temperatures, and the ice-covered shore tundra and adjacent sea ice conditions provided an appropriate locale for a conference dedicated in the spirit of the International Polar and Heliophysical Years 2007-2009 to the educational exploration of polar and icy world science of Earth and the solar system. The many scientific, educational, and cultural interactions with the local community of four thousand residents, sixty percent native Inupiat Eskimo, further provided an unforgettable experience of what life might be someday be like on other remote polar and icy worlds to be explored and eventually inhabited. Over one hundred active participants, more than half participating remotely, contributed science presentations and educational activities during this unique circumpolar and very "green" conference. Most remote contributions came via videoconference from the Swedish Institute of Space Physics (IRF) at Kiruna, Sweden, the EISCAT Svalbard Radar Facility at Spitzbergen, Norway, the University of Alaska at Fairbanks, NASA Goddard Space Flight Center and the Jet Propulsion Laboratory, the University of California at Berkeley, and the University of Arizona. A few contributors participated via teleconference, including one from the Polar Geophysical Institute at Apatity in Russia. These active contributions spanned up to thirteen time zones (Alaska to Russia) at various times during the conference. Primary videoconferencing support between Barrow and other sites was ably provided by the University of Alaska at Fairbanks, and local operators at each remote site collectively made this conference possible. Science presentations spanned the solar system from the polar Sun and heliospheric environment to Earth, Moon, Mars, Jupiter, Saturn, the Kuiper Belt, and the solar wind termination shock now crossed by both Voyager spacecraft. Barrow participants experienced look and feel of icy worlds like Europa by going "on the ice" during snowmobile expeditions to the near-shore sea ice and Point Barrow. Extensive educational outreach activities were conducted with the local Barrow township and North Slope Borough communities, partly through several interviews with local host Earl Finkler on Barrow's KBRW Radio, and through the NASA Digital Learning Network (DLN) "live from the top of the world" at Barrow. The Goddard robotic rover "Nanuq of the North" became a local celebrity. The complete science program and photo library, eventually also including video recordings of all main presentations, will be available at the new polargateways2008.gsfc.nasa.gov web site (old version: polargateways2008.org) with links to educational materials from the conference already accessible at sunearthday.nasa.gov/polarsunrise.

  10. Interhemispheric comparison of the development of the stratospheric polar vortex during fall - A 3-dimensional perspective for 1991-1992

    NASA Technical Reports Server (NTRS)

    Manney, Gloria L.; Zurek, Richard W.

    1993-01-01

    The development of the stratospheric polar vortex during fall and early winter in the Northern Hemisphere (NH) during 1991-1992, and the Southern Hemisphere (SH) during 1992 is examined using National Meteorological Center data. Compared to the NH, the polar vortex in the SH developed with less variability on short time scales, deepened more rapidly and continued to expand well into winter. Daily minimum temperatures in the lower stratosphere were lowest at equivalent seasonal dates in both hemispheres, but values below the condensation temperatures of polar stratospheric clouds occurred earlier, persisted much longer, and occupied a larger volume of air in the SH. These interhemispheric meteorological differences can account for some of the key features of the chlorine monoxide distributions observed by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite.

  11. The last polar dinosaurs: high diversity of latest Cretaceous arctic dinosaurs in Russia

    NASA Astrophysics Data System (ADS)

    Godefroit, Pascal; Golovneva, Lina; Shchepetov, Sergei; Garcia, Géraldine; Alekseev, Pavel

    2009-04-01

    A latest Cretaceous (68 to 65 million years ago) vertebrate microfossil assemblage discovered at Kakanaut in northeastern Russia reveals that dinosaurs were still highly diversified in Arctic regions just before the Cretaceous-Tertiary mass extinction event. Dinosaur eggshell fragments, belonging to hadrosaurids and non-avian theropods, indicate that at least several latest Cretaceous dinosaur taxa could reproduce in polar region and were probably year-round residents of high latitudes. Palaeobotanical data suggest that these polar dinosaurs lived in a temperate climate (mean annual temperature about 10°C), but the climate was apparently too cold for amphibians and ectothermic reptiles. The high diversity of Late Maastrichtian dinosaurs in high latitudes, where ectotherms are absent, strongly questions hypotheses according to which dinosaur extinction was a result of temperature decline, caused or not by the Chicxulub impact.

  12. The last polar dinosaurs: high diversity of latest Cretaceous arctic dinosaurs in Russia.

    PubMed

    Godefroit, Pascal; Golovneva, Lina; Shchepetov, Sergei; Garcia, Géraldine; Alekseev, Pavel

    2009-04-01

    A latest Cretaceous (68 to 65 million years ago) vertebrate microfossil assemblage discovered at Kakanaut in northeastern Russia reveals that dinosaurs were still highly diversified in Arctic regions just before the Cretaceous-Tertiary mass extinction event. Dinosaur eggshell fragments, belonging to hadrosaurids and non-avian theropods, indicate that at least several latest Cretaceous dinosaur taxa could reproduce in polar region and were probably year-round residents of high latitudes. Palaeobotanical data suggest that these polar dinosaurs lived in a temperate climate (mean annual temperature about 10 degrees C), but the climate was apparently too cold for amphibians and ectothermic reptiles. The high diversity of Late Maastrichtian dinosaurs in high latitudes, where ectotherms are absent, strongly questions hypotheses according to which dinosaur extinction was a result of temperature decline, caused or not by the Chicxulub impact. PMID:19089398

  13. Probing the spin polarization of current by soft x-ray imaging of current-induced magnetic vortex dynamics

    SciTech Connect

    Kasai, Shinya; Fischer, Peter; Im, Mi-Young; Yamada, Keisuke; Nakatani, Yoshinobu; Kobayashi, Kensuke; Kohno, Hiroshi; Ono, Teruo

    2008-12-09

    Time-resolved soft X-ray transmission microscopy is applied to image the current-induced resonant dynamics of the magnetic vortex core realized in a micron-sized Permalloy disk. The high spatial resolution better than 25 nm enables us to observe the resonant motion of the vortex core. The result also provides the spin polarization of the current to be 0.67 {+-} 0.16 for Permalloy by fitting the experimental results with an analytical model in the framework of the spin-transfer torque.

  14. Polar Bears from Space: Assessing Satellite Imagery as a Tool to Track Arctic Wildlife

    PubMed Central

    Stapleton, Seth; LaRue, Michelle; Lecomte, Nicolas; Atkinson, Stephen; Garshelis, David; Porter, Claire; Atwood, Todd

    2014-01-01

    Development of efficient techniques for monitoring wildlife is a priority in the Arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. We evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. We examined satellite images of a small island in Foxe Basin, Canada, occupied by a high density of bears during the summer ice-free season. Bears were distinguished from other light-colored spots by comparing images collected on different dates. A sample of ground-truthed points demonstrated that we accurately classified bears. Independent observers reviewed images and a population estimate was obtained using mark–recapture models. This estimate (: 94; 95% Confidence Interval: 92–105) was remarkably similar to an abundance estimate derived from a line transect aerial survey conducted a few days earlier (: 102; 95% CI: 69–152). Our findings suggest that satellite imagery is a promising tool for monitoring polar bears on land, with implications for use with other Arctic wildlife. Large scale applications may require development of automated detection processes to expedite review and analysis. Future research should assess the utility of multi-spectral imagery and examine sites with different environmental characteristics. PMID:25006979

  15. Arctic microbial ecosystems and impacts of extreme warming during the International Polar Year

    NASA Astrophysics Data System (ADS)

    Vincent, Warwick F.; Whyte, Lyle G.; Lovejoy, Connie; Greer, Charles W.; Laurion, Isabelle; Suttle, Curtis A.; Corbeil, Jacques; Mueller, Derek R.

    2009-11-01

    As a contribution to the International Polar Year program MERGE (Microbiological and Ecological Responses to Global Environmental change in polar regions), studies were conducted on the terrestrial and aquatic microbial ecosystems of northern Canada (details at: http://www.cen.ulaval.ca/merge/). The habitats included permafrost soils, saline coldwater springs, supraglacial lakes on ice shelves, epishelf lakes in fjords, deep meromictic lakes, and shallow lakes, ponds and streams. Microbiological samples from each habitat were analysed by HPLC pigment assays, light and fluorescence microscopy, and DNA sequencing. The results show a remarkably diverse microflora of viruses, Archaea (including ammonium oxidisers and methanotrophs), Bacteria (including filamentous sulfur-oxidisers in a saline spring and benthic mats of Cyanobacteria in many waterbodies), and protists (including microbial eukaryotes in snowbanks and ciliates in ice-dammed lakes). In summer 2008, we recorded extreme warming at Ward Hunt Island and vicinity, the northern limit of the Canadian high Arctic, with air temperatures up to 20.5 °C. This was accompanied by pronounced changes in microbial habitats: deepening of the permafrost active layer; loss of perennial lake ice and sea ice; loss of ice-dammed freshwater lakes; and 23% loss of total ice shelf area, including complete break-up and loss of the Markham Ice Shelf cryo-ecosystem. These observations underscore the vulnerability of Arctic microbial ecosystems to ongoing climate change.

  16. Polar bears from space: assessing satellite imagery as a tool to track Arctic wildlife

    USGS Publications Warehouse

    Stapleton, Seth P.; LaRue, Michelle A.; Lecomte, Nicolas; Atkinson, Stephen N.; Garshelis, David L.; Porter, Claire; Atwood, Todd C.

    2014-01-01

    Development of efficient techniques for monitoring wildlife is a priority in the Arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. We evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. We examined satellite images of a small island in Foxe Basin, Canada, occupied by a high density of bears during the summer ice-free season. Bears were distinguished from other light-colored spots by comparing images collected on different dates. A sample of ground-truthed points demonstrated that we accurately classified bears. Independent observers reviewed images and a population estimate was obtained using mark- recapture models. This estimate (N: 94; 95% Confidence Interval: 92-105) was remarkably similar to an abundance estimate derived from a line transect aerial survey conducted a few days earlier (N: 102; 95% CI: 69-152). Our findings suggest that satellite imagery is a promising tool for monitoring polar bears on land, with implications for use with other Arctic wildlife. Large scale applications may require development of automated detection processes to expedite review and analysis. Future research should assess the utility of multi-spectral imagery and examine sites with different environmental characteristics.

  17. Organochlorine contaminants in arctic marine food chains: identification, geographical distribution, and temporal trends in polar bears

    SciTech Connect

    Norstrom, R.J.; Simon, M.; Muir, D.C.G.; Schweinsburg, R.E.

    1988-09-01

    Contamination of Canadian arctic and subarctic marine ecosystems by organochlorine (OC) compounds was measured by analysis of polar bear (Ursus maritimus) tissues collected from 12 zones between 1982 and 1984. PCB congeners (S-PCB), chlordanes, DDT and metabolites, chlorobenzenes (S-CBz), hexachlorocyclohexane isomers (S-HC-H), and dieldrin were identified by high-resolution gas chromatography-mass spectrometry. Nonachlor-III, a nonachlor isomer in technical chlordane, was positively identified for the first time as an environmental contaminant. S-PCB and S-CHLOR accounted for >80% of the total organochlorines in adipose tissue. Six PCB congeners constituted approximately 93% of S-PCB in polar bears. Levels of most OCs were lowest in the high Arctic, intermediate in Baffin Bay, and highest in Hudson Bay. Levels of ..cap alpha..-HCH were evaluated in zones influenced by surface runoff. Levels of S-CHLOR were four times higher and levels of the other OCs were two times higher in adipose tissue of bears from Hudson Bay and Baffin Bay in 1984 than in adipose tissue archived since 1969 from these areas; levels of S-DDT did not change.

  18. Polar bears from space: assessing satellite imagery as a tool to track Arctic wildlife.

    PubMed

    Stapleton, Seth; LaRue, Michelle; Lecomte, Nicolas; Atkinson, Stephen; Garshelis, David; Porter, Claire; Atwood, Todd

    2014-01-01

    Development of efficient techniques for monitoring wildlife is a priority in the Arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. We evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. We examined satellite images of a small island in Foxe Basin, Canada, occupied by a high density of bears during the summer ice-free season. Bears were distinguished from other light-colored spots by comparing images collected on different dates. A sample of ground-truthed points demonstrated that we accurately classified bears. Independent observers reviewed images and a population estimate was obtained using mark-recapture models. This estimate (N: 94; 95% Confidence Interval: 92-105) was remarkably similar to an abundance estimate derived from a line transect aerial survey conducted a few days earlier (N: 102; 95% CI: 69-152). Our findings suggest that satellite imagery is a promising tool for monitoring polar bears on land, with implications for use with other Arctic wildlife. Large scale applications may require development of automated detection processes to expedite review and analysis. Future research should assess the utility of multi-spectral imagery and examine sites with different environmental characteristics. PMID:25006979

  19. Hematology of southern Beaufort Sea polar bears (2005-2007): Biomarker for an arctic ecosystem health sentinel

    USGS Publications Warehouse

    Kirk, Cassandra M.; Amstrup, S.; Swor, Rhonda; Holcomb, Darce; O'Hara, T. M.

    2010-01-01

    Declines in sea-ice habitats have resulted in declining stature, productivity, and survival of polar bears in some regions. With continuing sea-ice declines, negative population effects are projected to expand throughout the polar bear's range. Precise causes of diminished polar bear life history performance are unknown, however, climate and sea-ice condition change are expected to adversely impact polar bear (Ursus maritimus) health and population dynamics. As apex predators in the Arctic, polar bears integrate the status of lower trophic levels and are therefore sentinels of ecosystem health. Arctic residents feed at the apex of the ecosystem, thus polar bears can serve as indicators of human health in the Arctic. Despite their value as indicators of ecosystem welfare, population-level health data for U.S. polar bears are lacking. We present hematological reference ranges for southern Beaufort Sea polar bears. Hematological parameters in southern Beaufort Sea polar bears varied by age, geographic location, and reproductive status. Total leukocytes, lymphocytes, monocytes, eosinophils, and serum immunoglobulin G were significantly greater in males than females. These measures were greater in nonlactating females ages ???5, than lactating adult females ages ???5, suggesting that females encumbered by young may be less resilient to new immune system challenges that may accompany ongoing climate change. Hematological values established here provide a necessary baseline for anticipated changes in health as arctic temperatures warm and sea-ice declines accelerate. Data suggest that females with dependent young may be most vulnerable to these changes and should therefore be a targeted cohort for monitoring in this sentinel. ?? 2010 International Association for Ecology and Health.

  20. The impact of volcanic aerosol on the Northern Hemisphere stratospheric polar vortex: mechanisms and sensitivity to forcing structure

    NASA Astrophysics Data System (ADS)

    Toohey, M.; Krüger, K.; Bittner, M.; Timmreck, C.; Schmidt, H.

    2014-06-01

    Observations and simple theoretical arguments suggest that the Northern Hemisphere (NH) stratospheric polar vortex is stronger in winters following major volcanic eruptions. However, recent studies show that climate models forced by prescribed volcanic aerosol fields fail to reproduce this effect. We investigate the impact of volcanic aerosol forcing on stratospheric dynamics, including the strength of the NH polar vortex, in ensemble simulations with the Max Planck Institute Earth System Model. The model is forced by four different prescribed forcing sets representing the radiative properties of stratospheric aerosol following the 1991 eruption of Mt. Pinatubo: two forcing sets are based on observations, and are commonly used in climate model simulations, and two forcing sets are constructed based on coupled aerosol-climate model simulations. For all forcings, we find that temperature and zonal wind anomalies in the NH high latitudes are not directly impacted by anomalous volcanic aerosol heating. Instead, high latitude effects result from robust enhancements in stratospheric residual circulation, which in turn result, at least in part, from enhanced stratospheric wave activity. High latitude effects are therefore much less robust than would be expected if they were the direct result of aerosol heating. While there is significant ensemble variability in the high latitude response to each aerosol forcing set, the mean response is sensitive to the forcing set used. Significant differences, for example, are found in the NH polar stratosphere temperature and zonal wind response to two different forcing data sets constructed from different versions of SAGE II aerosol observations. Significant strengthening of the polar vortex, in rough agreement with the expected response, is achieved only using aerosol forcing extracted from prior coupled aerosol-climate model simulations. Differences in the dynamical response to the different forcing sets used imply that reproducing the polar vortex responses to past eruptions, or predicting the response to future eruptions, depends on accurate representation of the space-time structure of the volcanic aerosol forcing.

  1. Sailing the Open Polar Sea...Again: What Are You Teaching Your Children about the Arctic Ocean?

    ERIC Educational Resources Information Center

    Stockard, James W. Jr.

    1989-01-01

    Relates how a blunder about the Arctic Ocean and the polar ice cap made by the author in his first year of teaching led to a successful learning experience. Lists five important discussion topics that social studies teachers should use to teach about this remote, but strategic, part of the world. (LS)

  2. Large magnetic to electric field contrast in azimuthally polarized vortex beams generated by a metasurface (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Veysi, Mehdi; Guclu, Caner; Capolino, Filippo

    2015-09-01

    We investigate azimuthally E-polarized vortex beams with enhanced longitudinal magnetic field. Ideally, such beams possess strong longitudinal magnetic field on the beam axis where there is no electric field. First we formulate the electric field vector and the longitudinal magnetic field of an azimuthally E-polarized beam as an interference of right- and left-hand circularly polarized Laguerre Gaussian (LG) beams carrying the orbital angular momentum (OAM) states of -1 and +1, respectively. Then we propose a metasurface design that is capable of converting a linearly polarized Gaussian beam into an azimuthally E-polarized vortex beam with longitudinal magnetic field. The metasurface is composed of a rectangular array of double-layer double split-ring slot elements, though other geometries could be adopted as well. The element is specifically designed to have nearly a 180° transmission phase difference between the two polarization components along two orthogonal axes, similar to the optical axes of a half-wave plate. By locally rotating the optical axes of each metasurface element, the transmission phase profile of the circularly polarized waves over the metasurface can be tailored. Upon focusing of the generated vortex beam through a lens with a numerical aperture of 0.7, a 41-fold enhancement of the magnetic to electric field ratio is achieved on the beam axis with respect to that of a plane wave. Generation of beams with large magnetic field to electric field contrast can find applications in future spectroscopy systems based on magnetic dipole transitions, which are usually much weaker than electric dipole transitions.

  3. Evidence of large scale ozone depletion within the arctic polar cortex 94/95 based on airborne LIDAR measurements

    SciTech Connect

    Wirth, M.; Renger, W.

    1996-04-15

    The authors discuss aircraft measurements in the northern polar vortex which show that in the winter of 1994/95 that the ozone levels showed a 50 percent decline in the February to March period. This observation was correlated with simultaneous observations of stratospheric aerosols which support the argument that this density depletion was not the result of a purely dynamic process.

  4. Ultra-thin optical vortex phase plate based on the L-shaped nanoantenna for both linear and circular polarized incidences

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Guo, Zhongyi; Sun, Yongxuan; Shen, Fei; Li, Yan; Liu, Yi; Wang, Xinshun; Qu, Shiliang

    2015-11-01

    Based on the L-shaped gold nanoantennas, the ultra-thin optical vortex phase plates (VPPs) have been designed to generate the optical vortex beams with different topological charges, which are independent of the incident polarization states and suitable for both X/Y linear and circular polarization incidences simultaneously. The phase and amplitude of transmitted cross-polarization light can be simultaneously manipulated by changing two degrees of freedom (the length and the width) in the L-shaped nanoantenna unit. Evolution properties of the generated vortex beam are demonstrated and analyzed. The different interactions of angular momentums between light and the VPP in the different incident polarization states have also been investigated fully. The designed VPP shows a superior broadband characteristics in near-infrared wavelength ranging from 750 nm to 1200 nm, which enable a potential implication for integrated optics and vortex optics.

  5. The Interaction Between Dynamics and Chemistry of Ozone in the Set-Up Phase of the Northern Hemisphere Polar Vortex

    NASA Technical Reports Server (NTRS)

    Kawa, S.R.; Douglass, A. R.; Bevilacqua, R.; Margitan, J. J.; Sen, B.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Understanding stratospheric ozone loss to the point of accurately predicting ozone in the future requires correctly distinguishing chemical from transport-induced changes in ozone. For example, evaluating the impact of chlorine reduction in controlling stratospheric ozone loss requires estimating the amount of ozone lost in chemical reactions in the polar winter and spring. The Northern Hemisphere winter polar region is a particularly crucial and interesting area because it appears that the Northern vortex may currently be poised near the threshold of extreme ozone destruction such as that which now occurs annually in the Antarctic ozone "hole." In this presentation we explore the interaction of ozone transport and chemistry through the Northern late summer and fall seasons as the vortex circulation becomes established. This phase of the seasonal cycle determines the starting point for heterogeneous processes and chlorine-driven loss that take control in the winter vortex. Using a combination of profile data from POAM, HALOE, and in situ measurements, we show that relatively low ozone at high latitudes in the middle stratosphere is associated with vortex airmasses and that these ozone abundances evolve photochemically from characteristically higher values at the end of the summer. The zonal variance of ozone mixing ratio also increases greatly at this time consistent with increasing wave-driven transport. Comparison with a three-dimensional chemistry-transport model is used to generalize the findings from the limited set of observations and quantify the relative roles of transport and chemistry in determining the ozone mixing ratio distributions.

  6. GEOPHYSICAL RESEARCH LETTERS, VOL. 28, NO. 19, PAGES 3661-3664, OCTOBER 1, 2001 Observations of vertically thick polar stratospheric

    E-print Network

    Birner, Thomas

    of vertically thick polar stratospheric clouds and record low temperature in the Arctic vortex Rigel Kivi (67 N, 27 E) detected an extraordinarily thick polar stratospheric cloud layer of more than 8 km of inert chlorine species at the surface of polar stratospheric cloud (PSC) particles by complex

  7. Post-Equinox Evolution of Titan’s Detached Haze and South Polar Vortex Cloud

    NASA Astrophysics Data System (ADS)

    West, Robert A.; Ovanessian, A.; Del Genio, A.; Turtle, E. P.; Perry, J.; NcEwen, A.; Ray, T.; Roy, M.

    2013-10-01

    Instruments on the Cassini spacecraft discovered new phenomena related to the (presumably) seasonal behavior of photochemical haze and formation of the winter polar vortex. West et al. 2011 (Geophys. Res. Lett. , 380 , L06204. doi: 10.1029/2011GL046843) described a ‘detached’ haze layer that dropped in altitude from about 500 km in 2005 to about 360 km by late 2010. New images from the Cassini ISS camera show that the appearance of a detached layer is produced by a gap in the haze vertical profile and it is the gap rather than a haze layer that drops in altitude. Intensity profiles from different epochs form an envelope when plotted on top of each other, and the downward movement of the gap can be most easily seen when plotted that way. The movement of a gap rather than movement of a layer of enhanced haze density was suspected in the earlier publication but now it is more apparent. In recent months the gap became very shallow and the limb intensity profiles at a pixel scale ~10 km/pixel evolved from one local maximum/minimum into two local minima/maxima of smaller amplitude and appear to be trending toward the disappearance of relative maxima and minima, leaving a smooth envelope. These observations will require new developments in coupled dynamical and haze microphysical models as none of the current models account for this behavior. Titan’s south polar vortex cloud was detected concurrently by the ISS, VIMS, and CIRS instruments on Cassini in May of 2012. It has an unusual color (more yellow than Titan’s main haze in ISS images), morphology and texture (suggestive of a condensate cloud experiencing open cell convection) and displays a spectral feature at 220 cm-1 (Jennings et al., 2012, Astrophys. J. Lett. 761, L15 DOI: 10.1088/2041-8205/761/1/L15). These attributes point to a condensate of unknown composition. The haze patch is seen in images up to the present (July, 2013), but the latest images suggest a ‘softening’ or more diffuse edge than the earlier images. The feature is being engulfed by shadow as the season progresses, eventually preventing future observations in reflected sunlight. Acknowledgement: Part of this work was performed by the Jet Propulsion Lab, Calif. Inst. Of Technology.

  8. Reconstruction of the constituent distribution and trends in the Antarctic polar vortex from ER-2 flight observations

    SciTech Connect

    Schoeberl, M.R.; Lait, L.R. ); Newman, P.A.; Martin, R.L. ); Proffitt, M.H. ); Hartmann, D.L. ); Loewenstein, M.; Podolske, J.; Strahan, S.E.; Chan, K.R. ); Anderson, J. ); Gary, B. )

    1989-11-30

    Ozone, chlorine monoxide, and nitrous oxide concentrations have been measured in the south polar region. These measurements have been analyzed using conservative coordinate transformations to potential temperature-N{sub 2}O and potential temperature-potential vorticity space. The latter transformation is equivalent to interpreting trace species observations within the modified Lagrangian mean (MLM) coordinate system. The analysis shows that the MLM transformed ozone concentration decreases at about 0.06 ppmv (parts per million by volume) per day between 20 and 16 km altitude inside the polar vortex during the mid-August to mid-September period. These ozone changes must be chemical in origin; they are also collocated with the region of high CIO. Outside the CPR (chemically perturbed region) at the highest aircraft altitudes, ozone systematically increases, suggesting a diabatic cooling of the order of 0.3-0.6 K/d. Within the CPR the cooling rate appears to be less than 0.2 K/d. The MLM analysis technique creates a picture of the general chemical structure of the Austral polar vortex which shows that air deep within the chemically perturbed region has subsided substantially in relation to the air outside. However, there is also a tongue of high ozone air which extends from mid-latitudes downward along the stratospheric jet at 65{degree}W and 60{degree}S. An examination of the last three flight days, September 20-22, 1987, shows that during this period the polar vortex shifts systematically equatorward along the Antarctic Peninsula. Apparent changes in the constituents measured over this period result from sampling air progressively further into the vortex.

  9. The melting sea ice of Arctic polar cap in the summer solstice month and the role of ocean

    NASA Astrophysics Data System (ADS)

    Lee, S.; Yi, Y.

    2014-12-01

    The Arctic sea ice is becoming smaller and thinner than climatological standard normal and more fragmented in the early summer. We investigated the widely changing Arctic sea ice using the daily sea ice concentration data. Sea ice data is generated from brightness temperature data derived from the sensors: Defense Meteorological Satellite Program (DMSP)-F13 Special Sensor Microwave/Imagers (SSM/Is), the DMSP-F17 Special Sensor Microwave Imager/Sounder (SSMIS) and the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) instrument on the NASA Earth Observing System (EOS) Aqua satellite. We tried to figure out appearance of arctic sea ice melting region of polar cap from the data of passive microwave sensors. It is hard to explain polar sea ice melting only by atmosphere effects like surface air temperature or wind. Thus, our hypothesis explaining this phenomenon is that the heat from deep undersea in Arctic Ocean ridges and the hydrothermal vents might be contributing to the melting of Arctic sea ice.

  10. Autocatalytic release of bromine from Arctic snow pack during polar sunrise

    SciTech Connect

    Tang, T.; McConnell, J.C.

    1996-09-01

    Measurements and modeling studies strongly suggest that spring time depletion of ozone in the Arctic planetary boundary layer (PBL) is due to catalytic destruction by bromine atoms. However, the source of the bromine is uncertain. In this note, we propose that the source of the bromine at polar sunrise is the snow pack on the ice covering Arctic ocean and that it is released auto-catalytically, stimulated by a bromine seed from one of the brominated organic compounds, such as CHBr{sub 3}, by photolysis. In this manner {approximately}100 pptv of bromine can be transferred to the atmosphere where it can reside in the gas phase or, by scavenging, be partitioned in the aerosol or ice crystal phase. Moreover, it appears that heterogeneous recycling of bromine may be a process that self-terminates as ozone depletes to low levels. We also have included chlorine chemistry in the model in order to simulate inferred levels of chlorine atoms. This is important as it results in the production of HCHO which acts to convert post ozone depletion active bromine into HBr which is then returned to the snow pack or scavenged by aerosols or ice crystals. {copyright} American Geophysical Union 1996

  11. Impact of radiosonde observations on forecasting summertime Arctic cyclone formation

    NASA Astrophysics Data System (ADS)

    Yamazaki, Akira; Inoue, Jun; Dethloff, Klaus; Maturilli, Marion; König-Langlo, Gert

    2015-04-01

    The impact of Arctic radiosonde observations on the forecasting of the 2012 early August Arctic cyclone AC12—the "strongest" since records began—has been investigated using an observing system experiment (OSE). An atmospheric ensemble reanalysis (ALERA2) was used as the control experiment (CTL) to reproduce the development of the Arctic cyclone and surrounding large-scale atmospheric fields. The OSE applies the same reanalysis as the CTL except for the exclusion of radiosonde observations from the German icebreaker Polarstern, which cruised near Svalbard during mid-July to early August 2012. Comparison of the two reanalyses revealed a difference in the upper tropospheric circulation over northern mid-Eurasia, just before the Arctic cyclone developed, in the form of a stronger tropopause polar vortex in the CTL. This indicated that the upper tropospheric field in the CTL had greater potential for baroclinic instability over mid-Eurasia. Ensemble predictions were then conducted using the two reanalyses as initial values at which the tropopause polar vortex approached northern mid-Eurasia. The CTL prediction reproduced the formation of the Arctic cyclone, but the OSE shows a significantly weaker one. These results indicate that the improved reproduction of upper tropospheric circulation in the Arctic region due to additional radiosonde observations from a mobile platform was indispensable for the prediction of AC12. In particular, observations being acquired far from the Arctic cyclone affect the prediction of the cyclone via the upper tropospheric circulation in the atmospheric west wind drift.

  12. Dynamical response of the Arctic atmospheric boundary layer to sea ice in Polar WRF model

    NASA Astrophysics Data System (ADS)

    Seo, Hyodae; Yang, Jiayan

    2014-05-01

    Impact of sea ice concentration (SIC) on the Arctic atmospheric boundary layer (ABL) is investigated using a Polar-optimized version of the Weather Research and Forecasting (Polar WRF) model. A detailed comparison of the simulations forced with various SIC datasets to historical ship and ice station based data are presented demonstrating the reasonable representation of the observed ABL evolution by the Polar WRF. Further, two dynamically distinctive effects of sea ice on the surface wind were found, which act on different spatial scales. Reduced SIC lowers ABL stability, thereby increasing surface wind (W10) speeds. The spatial scale of this response is comparable to the basin-scale of the SIC difference. In contrast, near-surface geostrophic wind (Wg) shows a strong response in the MIZ, where, a good spatial correspondence exists among the Laplacian of the sea level pressure (SLP), the surface wind convergence, and the vertical motion within the ABL. This indicates that SIC affects Wg through variation in SLP but on a much narrower scale. Larger-amplitude and broader-scale response in W10 implies that surface wind stress derived from Wg to drive ice-ocean models may not fully reflect the effect of SIC changes.

  13. Cooling of the Arctic and Antarctic polar stratospheres due to ozone depletion

    SciTech Connect

    Randel, W.J.; Wu, F.

    1999-05-01

    Long time records of stratospheric temperatures indicate that substantial cooling has occurred during spring over polar regions of both hemispheres. These cooling patterns are coincident with observed recent ozone depletions. Time series of temperature from radiosonde, satellite, and National Centers for Environmental Prediction reanalysis data are analyzed in order to isolate the space-time structure of the observed temperature changes. The Antarctic data show strong cooling (of order 6--10 K) in the lower stratosphere ({approximately} 12--21 km) since approximately 1985. The cooling maximizes in spring (October--December), with small but significant changes extending throughout Southern Hemisphere summer. No Antarctic temperature changes are observed during midwinter. Significant warming is found during spring at the uppermost radiosonde data level (30 mb, {approximately} 24 km). These observed temperature changes are all consistent with model predictions of the radiative response to Antarctic polar ozone depletion. Winter and spring temperatures in Northern Hemisphere polar regions also indicate a strong cooling in the 1990s, and the temperature changes are coherent with observed ozone losses. The overall space-time patterns are similar between both hemispheres, suggesting that the radiative response to ozone depletion is an important component of the Arctic cooling as well.

  14. Accuracy of Modelled Stratospheric Temperatures in the Winter Arctic Vortex from Infra Red Montgolfier Long Duration Balloon Measurements

    NASA Technical Reports Server (NTRS)

    Pommereau, J.-P.; Garnier, A.; Knudson, B. M.; Letrenne, G.; Durand, M.; Cseresnjes, M.; Nunes-Pinharanda, M.; Denis, L.; Newman, P. A.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The temperature of the stratosphere has been measured in the Arctic vortex every 9-10 minutes along the trajectory of four Infra Red Montgolfier long duration balloons flown for 7 to 22 days during the winters of 1997 and 1999. From a number of comparisons to independent sensors, the accuracy of the measurements is demonstrated to be plus or minus 0.5 K during nighttime and at altitude below 28 km (10 hPa). The performances of the analyses of global meteorological models, European Center for Medium Range Weather Forecasts (ECMWF) 31 and 50 levels, United Kingdom Meteorological Office (UKMO), Data Assimilation Office (DAO), National Climatic Prediction Center (NCEP) and NCEP/NCAR reanalysis, used in photochemical simulations of ozone destruction and interpretation of satellite data, are evaluated by comparison to this large (3500 data points) and homogeneous experimental data set. Most of models, except ECMWF31 in 1999, do show a smal1 average warm bias of between 0 and 1.6 K, with deviations particularly large, up to 20 K at high altitude (5hPa) in stratospheric warming conditions in 1999. Particularly wrong was ECMWF 31 levels near its top level at 10 hPa in 1999 where temperature 25 K colder than the real atmosphere were reported. The average dispersion between models and measurements varies from plus or minus 1.0 to plus or minus 3.0 K depending on the model and the year. It is shown to be the result of three contributions. The largest is a long wave modulation likely caused by the displacement of the temperature field in the analyses compared to real atmosphere. The second is the overestimation of the vertical gradient of temperature particularly in warming conditions, which explains the increase of dispersion from 1997 to 1999. Unexpectedly, the third and smallest (plus or minus 0.6-0.7 K) is the contribution of meso and subgrid scale vertical and horizontal features associated to the vertical propagation of orographic or gravity waves. Compared to other models, the newly available ECMWF 50 levels version assimilating the high vertical resolution radiances of the space borne Advanced Microwave Sounding Unit, performs significantly better (0.03 plus or minus 1.12 K on average between 10 and 140 hPa in 1999) than other models.

  15. Leveraging scientific credibility about Arctic sea ice trends in a polarized political environment.

    PubMed

    Jamieson, Kathleen Hall; Hardy, Bruce W

    2014-09-16

    This work argues that, in a polarized environment, scientists can minimize the likelihood that the audience's biased processing will lead to rejection of their message if they not only eschew advocacy but also, convey that they are sharers of knowledge faithful to science's way of knowing and respectful of the audience's intelligence; the sources on which they rely are well-regarded by both conservatives and liberals; and the message explains how the scientist arrived at the offered conclusion, is conveyed in a visual form that involves the audience in drawing its own conclusions, and capsulizes key inferences in an illustrative analogy. A pilot experiment raises the possibility that such a leveraging-involving-visualizing-analogizing message structure can increase acceptance of the scientific claims about the downward cross-decade trend in Arctic sea ice extent and elicit inferences consistent with the scientific consensus on climate change among conservatives exposed to misleadingly selective data in a partisan news source. PMID:25225380

  16. Polar Stratospheric Cloud formation and denitrification during the Arctic winter 2009/2010 and 2010/2011

    NASA Astrophysics Data System (ADS)

    Khosrawi, Farahnaz; Urban, Joachim; Pitts, Michael C.; Kirner, Oliver; Braesicke, Peter; Santee, Michelle L.; Manney, Gloria L.; Murtagh, Donal

    2015-04-01

    The sedimentation of HNO3 containing polar stratospheric cloud particles leads to a permanent removal of HNO3 from the stratosphere. The so-called denitrification is an effect that plays an important role in stratospheric ozone depletion. The Arctic winter 2009/2010 and 2010/2011 were both quite unique. The Arctic winter 2010/2011 was one of the coldest winters on record leading to the strongest depletion of ozone measured in the Arctic. Though the Arctic winter 2009/2010 was rather warm in the climatological sense it was distinguished by an exceptionally cold stratosphere from mid December 2009 to mid January 2010 leading to prolonged PSC formation and significant denitrification. Model simulations and space-borne observations are used to investigate PSC formation and denitrification during these two winters. Model simulations were performed with the atmospheric chemistry-climate model ECHAM5/MESSy Atmospheric Chemistry (EMAC) and compared to observations by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations Satellite (CALIPSO) and the Odin Sub-Millimetre Radiometer (Odin/SMR) as well as with observations from the Microwave Limb Sounder on Aura (Aura/MLS). While PSCs were present during the Arctic winter 2010/2011 over nearly four months, from mid December to end of March, they were not as persistent as the ones that occurred during the shorter (one month) cold period during the Arctic winter 2009/2010. Although the PSC season during the Arctic winter 2009/2010 was much shorter than in 2010/2011, denitrification during the Arctic winter 2009/2010 was similar in magnitude than during 2010/2011.

  17. Changing Arctic Ecosystems: Updated forecast: Reducing carbon dioxide (CO2) emissions required to improve polar bear outlook

    USGS Publications Warehouse

    Oakley, Karen L.; Atwood, Todd C.; Mugel, Douglas N.; Rode, Karyn D.; Whalen, Mary E.

    2015-01-01

    The Arctic is warming faster than other regions of the world due to the loss of snow and ice, which increases the amount of solar energy absorbed by the region. The most visible consequence has been the rapid decline in sea ice over the last 3 decades-a decline projected to bring long ice-free summers if greenhouse gas (GHG) emissions are not significantly reduced. The polar bear (Ursus maritimus) depends on sea ice over the biologically productive continental shelves of the Arctic Ocean as a platform for hunting seals. In 2008, the U.S. Fish and Wildlife Service listed the polar bear as threatened under the Endangered Species Act (ESA) due to the threat posed by sea ice loss. The polar bear was the first species to be listed due to forecasted population declines from climate change.

  18. The Influence of Arctic Sea Ice Extent on Polar Cloud Fraction and Vertical Structure and Implications for Regional Climate

    NASA Technical Reports Server (NTRS)

    Palm, Stephen P.; Strey, Sara T.; Spinhirne, James; Markus, Thorsten

    2010-01-01

    Recent satellite lidar measurements of cloud properties spanning a period of five years are used to examine a possible connection between Arctic sea ice amount and polar cloud fraction and vertical distribution. We find an anti-correlation between sea ice extent and cloud fraction with maximum cloudiness occurring over areas with little or no sea ice. We also find that over ice free regions, there is greater low cloud frequency and average optical depth. Most of the optical depth increase is due to the presence of geometrically thicker clouds over water. In addition, our analysis indicates that over the last 5 years, October and March average polar cloud fraction has increased by about 7 and 10 percent, respectively, as year average sea ice extent has decreased by 5 to 7 percent. The observed cloud changes are likely due to a number of effects including, but not limited to, the observed decrease in sea ice extent and thickness. Increasing cloud amount and changes in vertical distribution and optical properties have the potential to affect the radiative balance of the Arctic region by decreasing both the upwelling terrestrial longwave radiation and the downward shortwave solar radiation. Since longwave radiation dominates in the long polar winter, the overall effect of increasing low cloud cover is likely a warming of the Arctic and thus a positive climate feedback, possibly accelerating the melting of Arctic sea ice.

  19. Influence of Arctic Sea Ice Extent on Polar Cloud Fraction and Vertical Structure and Implications for Regional Climate

    NASA Technical Reports Server (NTRS)

    Palm, Stephen P.; Strey, Sara T.; Spinhirne, James; Markus, Thorsten

    2010-01-01

    Recent satellite lidar measurements of cloud properties spanning a period of 5 years are used to examine a possible connection between Arctic sea ice amount and polar cloud fraction and vertical distribution. We find an anticorrelation between sea ice extent and cloud fraction with maximum cloudiness occurring over areas with little or no sea ice. We also find that over ice!free regions, there is greater low cloud frequency and average optical depth. Most of the optical depth increase is due to the presence of geometrically thicker clouds over water. In addition, our analysis indicates that over the last 5 years, October and March average polar cloud fraction has increased by about 7% and 10%, respectively, as year average sea ice extent has decreased by 5% 7%. The observed cloud changes are likely due to a number of effects including, but not limited to, the observed decrease in sea ice extent and thickness. Increasing cloud amount and changes in vertical distribution and optical properties have the potential to affect the radiative balance of the Arctic region by decreasing both the upwelling terrestrial longwave radiation and the downward shortwave solar radiation. Because longwave radiation dominates in the long polar winter, the overall effect of increasing low cloud cover is likely a warming of the Arctic and thus a positive climate feedback, possibly accelerating the melting of Arctic sea ice.

  20. Particle size distributions in Arctic polar stratospheric clouds, growth and freezing of sulfuric acid droplets, and implications for cloud formation

    NASA Technical Reports Server (NTRS)

    Dye, James E.; Baumgardner, D.; Gandrud, B. W.; Kawa, S. R.; Kelly, K. K.; Loewenstein, M.; Ferry, G. V.; Chan, K. R.; Gary, B. L.

    1992-01-01

    The paper uses particle size and volume measurements obtained with the forward scattering spectrometer probe model 300 during January and February 1989 in the Airborne Arctic Stratospheric Experiment to investigate processes important in the formation and growth of polar stratospheric cloud (PSC) particles. It is suggested on the basis of comparisons of the observations with expected sulfuric acid droplet deliquescence that in the Arctic a major fraction of the sulfuric acid droplets remain liquid until temperatures at least as low as 193 K. It is proposed that homogeneous freezing of the sulfuric acid droplets might occur near 190 K and might play a role in the formation of PSCs.

  1. Denitrification in the Arctic mid-winter 2004/2005 observed by airborne submillimeter radiometry

    NASA Technical Reports Server (NTRS)

    Kleinbohl, Armin; Bremer, Holger; Kullmann, Harry; Kuttippurath, Jayanarayanan; Browell, Edward V.; Canty, Timothy; Salawitch, Ross J.; Toon, Geoffrey C.; Nothol, Justus

    2005-01-01

    We present measurements of unusually low mixing ratios of HNO3 in the exceptionally cold Arctic vortex of late-January and early-February 2005. The measurements were obtained by the airborne submillimeter radiometer ASUR during the polar aura validation experiment (PAVE). The distribution of HNO3 inside the vortex reaches minima below 4 ppbv around 22 km altitude and maxima above 13 ppbv around 16 km altitude, with a considerable spatial variability.

  2. El Chichon volcanic debris in an Arctic tropopause fold

    SciTech Connect

    Shapiro, M.A.; Schnell, R.C.; Parungo, F.P.; Oltmans, S.J.; Bodhaine, B.A.

    1984-05-01

    A research flight with the NOAA WP-3D aircraft revealed evidence for stratospheric-tropospheric exchange within the Arctic through tropopause folding on the flank of the polar vortex. Observations showed descent of the tropopause and of stratospheric ozone to 700 mb along the west coast of Greenland. Measurements of condensation nuclei and analysis of high volume impactor samples documented the presence of volcanic debris probably from the 1982 El Chichon eruption, including H/sub 2/SO/sub 4/ droplets, within the polar vortex and associated tropopause fold. 14 references, 6 figures.

  3. El Chichon volcanic debris in an Arctic tropopause fold

    NASA Astrophysics Data System (ADS)

    Shapiro, M. A.; Schnell, R. C.; Parungo, F. P.; Oltmans, S. J.; Bodhaine, B. A.

    A research flight with the NOAA WP-3D aircraft revealed evidence for stratospheric-tropospheric exchange within the Arctic through tropopause folding on the flank of the polar vortex. Observations showed descent of the tropopause and of stratospheric ozone to 700 mb along the west coast of Greenland. Measurements of condensation nuclei and analysis of high volume impactor samples documented the presence of volcanic debris probably from the 1982 El Chichon eruption, including H2SO4 droplets, within the polar vortex and associated tropopause fold.

  4. Nitric oxide measurements in the Arctic winter stratosphere

    NASA Technical Reports Server (NTRS)

    Fahey, D. W.; Kawa, S. R.; Chan, K. R.

    1990-01-01

    Measurements of NO from five flights of the NASA ER-2 aircraft during the Airborne Arctic Stratospheric Expedition are presented. The NO values and vertical gradient near 60 deg N latitude are similar to previous measurements near 50 deg N in winter (Ridley et al., 1984, 1987). The NO latitudinal gradient is distinctly negative outside of the polar vortex, approaching zero at the boundary of the vortex, and remaining below the 20 pptv detection limit inside the vortex. Steady state NO2 and NO(x) (NO + NO2) are calculated from measured NO, O3, and ClO, and modeled photodissociation rates. NO(x) outside the vortex shows a negative dependence on latitude and solar zenith angle. Low NO(x) and NO(x)/NO(y), inside and near the vortex boundary may be indications of heterogeneous removal of ClONO2 and N2O5.

  5. Creation of a three-dimensional super-resolution transversally polarized focal spot by 4? tight focusing of radially polarized vortex beams

    NASA Astrophysics Data System (ADS)

    Nie, Zhongquan; Shi, Guang; Li, Dongyu; Zhang, Xueru; Wang, Yuxiao; Song, Yinglin

    2015-05-01

    The intensity profiles near the focus of a 4? high numerical aperture focusing configuration for two counter-propagating radially polarized hollow Gaussian (HG) vortex beams are examined numerically. Theoretical calculations manifest that, in contrast to the single-objective focusing system, a three-dimensional super-resolution focal spot with purely transverse polarization can be formed. Such an unusual pattern stems from combining the faultlessly destructive interference of the longitudinal component of the electric field with the constructive interference of the transverse components (azimuthal and radial components) created by the two counter-propagating radially polarized vortex beams, as well as benefits from the higher-order HG mode (e.g., n = 4) to govern the aspect ratio of the focal spot. Moreover, the tolerances on focusing performance for modest displacement from the center of the HG beams with different orders are researched in detail. We expect that such a three-dimensional super-resolution field with transverse polarization can be extensively used in super-resolution confocal microscopy and three-dimensional high-density optical storage.

  6. Evolution of the Antarctic polar vortex in spring: Response of a GCM to a prescribed Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Boville, B. A.; Kiehl, J. T.; Briegleb, B. P.

    1988-01-01

    The possible effect of the Antartic ozone hole on the evolution of the polar vortex during late winter and spring using a general circulation model (GCM) is examined. The GCM is a version of the NCAR Community Climate Model whose domain extends from the surface to the mesosphere and is similar to that described on Boville and Randel (1986). Ozone is not a predicted variable in the model. A zonally averaged ozone distribution is specified as a function of latitude, pressure and month for the radiation parameterization. Rather that explicitly address reasons for the formation of the ozone hole, researchers postulate its existence and ask what effect it has on the subsequent evolution of the vortex. The evolution of the model when an ozone hole is imposed is then discussed.

  7. Cosmogenic 35S: A unique tracer to Antarctic atmospheric chemistry and the polar vortex

    NASA Astrophysics Data System (ADS)

    Priyadarshi, Antra; Dominguez, Gerardo; Savarino, Joel; Thiemens, Mark

    2011-07-01

    The cosmogenic radionuclide 35S (half life ˜87 d) exists in both 35SO2 gas and 35SO42- aerosol phase in the atmosphere. Cosmogenic 35S fulfils a unique niche in that it has an ideal half-life for use as a tracer of atmospheric processes, possesses a gas phase precursor and undergoes gas to particle conversion, providing a chronometer that complements other measurements of radiogenic isotopes of different half lives and chemical properties. Based on radiogenic 35S measurements and concomitant model calculations, we demonstrate that 35S is a unique tracer to understand stratospheric-tropospheric air mass transport dynamics and the atmospheric oxidation capacity on a short time scale. Reported are the first measurements of 35S contained in SO42- aerosols (bulk and size aggregated) at Antarctica. 35SO42- concentrations at Dome C and Dumont D'Urville exhibit summer maxima and winter minima with a secondary winter peak. Higher oxidative capacity of the atmosphere and long range transport of mid latitude air increases 35SO42- activity in summer whereas a lack of air mass mixing coupled with low oxidant concentration in winter significantly decreases 35SO42- activity. A 3% contribution from stratospheric 35SO42- into the free troposphere during stratosphere-troposphere air mass mixing accounts for the secondary winter 35SO42- peak. In the future, this work will be extended to 35S activity measurements of both gas and aerosol phases to further understand gas to particle conversion, vortex dynamics and trace polar stratospheric cloud sedimentation frequency.

  8. Temporal trends and transport within and around the Antarctic polar vortex during the formation of the 1987 Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Proffitt, M. H.; Powell, J. A.; Tuck, A. F.; Fahey, D. W.; Kelly, K. K.; Loewenstein, M.; Podolske, J. R.; Chan, K. Roland

    1988-01-01

    During AAOE in 1987 an ER-2 high altitude aircraft made twelve flights out of Punta Arenas, Chile (53 S, 71 W) into the Antarctic polar vortex. The aircraft was fitted with fast response instruments for in situ measurements of many trace species including O3, ClO, BrO, NO sub y, NO, H2O, and N2O. Grab samples of long-lived tracers were also taken and a scanning microwave radiometer measured temperatures above and below the aircraft. Temperature, pressure, and wind measurements were also made on the flight tracks. Most of these flights were flown to 72 S, at a constant potential temperature, followed by a dip to a lower altitude and again assuming a sometimes different potential temperature for the return leg. The potential temperature chosen was 425 K (17 to 18 km) on 12 of the flight legs, and 5 of the flight legs were flown at 450 K (18 to 19 km). The remaining 7 legs of the 12 flights were not flown on constant potential temperature surfaces. Tracer data have been analyzed for temporal trends. Data from the ascents out of Punta Arenas, the constant potential temperature flight legs, and the dips within the vortex are used to compare tracer values inside and outside the vortex, both with respect to constant potential temperature and constant N2O. The time trend during the one-month period of August 23 through September 22, 1987, shows that ozone decreased by 50 percent or more at altitudes form 15 to 19 km. This trend is evident whether analyzed with respect to constant potential temperature or constant N2O. The trend analysis for ozone outside the vortex shows no downward trend during this period. The analysis for N2O at a constant potential temperature indicates no significant trend either inside or outside the vortex; however, a decrease in N2O with an increase in latitude is evident.

  9. A case study of high Arctic anthropogenic disturbance to polar desert permafrost and ecosystems

    NASA Astrophysics Data System (ADS)

    Becker, M. S.; Pollard, W. H.

    2013-12-01

    One of the indirect impacts of climate change on Arctic ecosystems is the expected increase of industrial development in high latitudes. The scale of terrestrial impacts cannot be known ahead of time, particularly due to a lack of long-term impact studies in this region. With one of the slowest community recovery rates of any ecosystem, the high Artic biome will be under a considerable threat that is exacerbated by a high susceptibility to change in the permafrost thermal balance. One such area that provides a suitable location for study is an old airstrip near Eureka, Ellesmere Island, Nunavut (80.0175°N, 85.7340°W). While primarily used as an ice-runway for winter transport, the airstrip endured a yearly summer removal of vegetation that continued from 1947 until its abandonment in 1951. Since then, significant vegetative and geomorphic differences between disturbed and undisturbed areas have been noted in the literature throughout the decades (Bruggemann, 1953; Beschel, 1963; Couture and Pollard, 2007), but no system wide assessment of both the ecosystem and near-surface permafrost has been conducted. Key to our study is that the greatest apparent geomorphic and vegetative changes have occurred and persisted in areas where underlying ice-wedges have been disturbed. This suggests that the colonizing communities rapidly filled new available thermokarst niches and have produced an alternative ice-wedge stable state than the surrounding polar desert. We hypothesize that disturbed areas will currently have greater depths of thaw (deeper active layers) and degraded ice-wedges, with decreased vegetation diversity but higher abundance due to a changed hydrological balance. To test this a comprehensive set of near-surface active layer and ecosystem measurements were conducted. Permafrost dynamics were characterized using probing and high-frequency Ground Penetrating Radar (500 MHz) to map the near-surface details of ice-wedges and active layer. Vegetation was measured using quadrat sampling for species richness and abundance. Soil measures consisted of temperature at depth, moisture content, and bioavailable nutrients, all augmented with hourly microclimate data. NMDS ordination was performed as an exploratory analysis of clustering between disturbed/undisturbed microsite differences. Further statistical analysis showed that disturbed polygon tops have an active layer 30% deeper than other microsites (p < .001) despite having no greater vegetation cover than undisturbed polygon tops. Conversely, disturbed troughs show no difference in active layer, but their soils have double the water content of other microsites (p < .001), likely accounting for a significantly greater, but less-diverse, biomass that may be buffering the active layer from further development. Our results suggest that a disturbance to the thermal regime of high Arctic ice-wedge polygon systems results in long-lasting and significant effects on the polar desert landscape. Understanding how the polar desert responds to disturbance after 60 years of ';recovery' will provide useful information for applying conceptual thermal models of landscape disturbance in the high Arctic, as well as information to governments and industries hoping to plan and minimize their impacts.

  10. The Polar Crust Project- BSC Diversity and Variability in the Arctic and Antarctica

    NASA Astrophysics Data System (ADS)

    Williams, Laura; Borchhardt, Nadine; Komisc-Buchmann, Karin; Becker, Burkhard; Karsten, Ulf; Büdel, Burkhard

    2015-04-01

    The Polar Crust Project is a newly funded DFG initiative that aims to provide a precise evaluation of the biodiversity of eukaryotic green microalgae and cyanobacteria in Biological Soil Crusts (BSC) isolated from the Antarctic Peninsula and Arctic Svalbard. This project will include a thorough investigation into the composition of BSC in the Polar regions, this especially is important for Svalbard due to the severe lack of any previous research on such communities in this area. During our expedition to Spitsbergen, Svalbard in August 2014 we were particularly surprised to find that the coverage of BSC is extremely high and is certainly the dominant vegetation type around Ny Ålesund. Due to this discovery the project has now been extended to include long term measurements of CO2 gas exchange in order to gain exact seasonal carbon fixation rates and therefore discovering how the BSC contributes to the ecosystems carbon balance. The research areas of Spitsbergen were centred around 2 localities: Ny-Ålesund is a research town, home to the AWIPEV station, on the Brøgger peninsula. Longyearbyen, which is the largest settlement on the island, is found in the valley Longyeardalen on the shore of Adventfjorden. Areas where BSC is the prevalent vegetation type were identified, 6 around Ny-Ålesund and 4 for Longyearbyen, and vegetation surveys were conducted. This entailed 625 single point measurements at each site and identifying the crust/or other cover type. For example, green algal lichen, cyanobacterial crust, higher plant, open soil. Samples were also taken at every location in order to study the green algal and cyanobacterial diversity. The vegetation survey will allow us to get a good overview of the BSC composition at the different sites. In January 2015 an expedition to the Antarctic Peninsular took place, here the sampling method was repeated and therefore both Polar Regions BSC composition can be described and compared. Here, we wish to introduce the Polar Crust Project and present the results of the vegetation study to date. This should provide a general overview of what we hope to be a very interesting and important project in the further understanding of Polar BSC and how they stand to cope and/or change in the face of global warming.

  11. A comparison of Arctic lower stratospheric winter temperatures for 1988-89 with temperatures since 1964

    NASA Technical Reports Server (NTRS)

    Nagatani, Ronald M.; Miller, Alvin J.; Gelman, Melvyn E.; Newman, Paul A.

    1990-01-01

    Lower stratospheric temperatures during the Airborne Arctic Stratospheric Expedition are compared with temperatures available since January, 1964. January, 1989, was the coldest averaged January in the last 26 years at high latitude, lower stratospheric levels. There have been other months with temperatures almost as low as the level of January, 1989, and localized temperatures (e.g., minimum polar vortex temperatures) have been lower than that encountered in January 1989. February, 1989, was warmer than average and March, 1989, had some of the highest polar vortex temperatures in the last 26 years. Conditions were therefore not very favorable for Polar Stratospheric Cloud (PSC) formation into early spring.

  12. A comparison of Arctic lower stratospheric winter temperatures for 1988-89 with temperatures since 1964

    SciTech Connect

    Nagatani, R.M.; Miller, A.J.; Gelman, M.E. ); Newman, P.A. )

    1990-03-01

    Lower stratospheric temperatures during the Airborne Arctic Stratospheric Expedition are compared with temperatures available since January, 1964. January, 1989, was the coldest average January in the last 26 years at high altitude, lower stratospheric levels. There have been other months with temperatures almost as low as the level of January, 1989, and localized temperatures (e.g., minimum polar vortex temperatures) have been lower than that encountered in January 1989. February, 1989, was warmer than average and March, 1989, had some of the highest polar vortex temperatures in the last 26 years. Conditions were therefore not very favorable for Polar Stratospheric Cloud (PSC) formation into early spring.

  13. Integrating Access to Arctic Environmental Change and Human Health Research for the International Polar Year and Beyond

    NASA Astrophysics Data System (ADS)

    Garrett, C. L.

    2006-12-01

    Each day, people in the communities of the Arctic face challenges to their health and well-being from changing climatic and environmental conditions and increasing levels of pollution to emerging infectious diseases. For this reason, it is critical that Arctic researchers and residents have access to timely, accurate, and relevant information addressing their unique concerns. To meet this need, the National Library of Medicine (NLM) and the University of Alaska Anchorage (UAA) have developed the Arctic Health website, www.arctichealth.org. The website provides an easy-to-use one-stop shop for information on the diverse health-related aspects of the Arctic region. It is organized around relevant topics, including climate change and environmental health, traditional healing and telehealth/telemedicine. The Arctic Health website provides links to the most reliable resources available from local, state, and international agencies, universities, and professional organizations. Two major goals of the site are to create a comprehensive, accessible repository for various media and a listing of research projects, past and present that relate to climate change and human health in the Arctic. To increase the site's relevance, the project has established and continues to create collaborations with researchers, communities, and other organizations to supply publications not available elsewhere, including gray literature, streaming video of traditional healers, and oral histories. These collaborations will also help ensure a database with a comprehensive list of research projects being done in the Arctic, from the international to the local level. Finding ways to negotiate the legal, cultural and national concerns of data sharing are a continuing job for the management team. All of this helps to create a system that will eventually track and ensure that data and reports from the research database translate to the publications database. As part of these efforts, the site is hosting the Arctic Human Health Initiative (AHHI), the human health focus of the International Polar Year activities. AHHI will coordinate research in the areas of infectious disease; the effects of anthropogenic pollution, UV radiation, and climate variability on human health; and telehealth innovations. A major goal of AHHI is the better integration of the findings of Arctic health research through outreach programs and public education.

  14. Airborne lidar observations in the wintertime Arctic stratosphere - Ozone

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Ismail, S.; Carter, A. F.; Butler, C. F.; Fenn, M. A.; Kooi, S. A.; Tuck, A. F.; Toon, O. B.; Loewenstein, M.; Schoeberl, M. R.

    1990-01-01

    Large-scale distributions of ozone (O3) were measured with an airborne lidar system as part of the 1989 Airborne Arctic Stratospheric Expedition. Measurements of O3 distributions were obtained between January 6 and February 15, 1989, on 15 long-range flights into the polar vortex from the Solar Air Station, Norway. The observed O3 distribution was found to clearly indicate the edge of the polar vortex and to be an effective tracer of dynamical processes in the lower stratosphere. On the last two flights of the expedition, large regions with reduced O3 levels were observed by the lidar inside the polar vortex. Ozone had decreased by as much as 17 percent in the center of these areas, and using the in situ measurements made on the ER-2 aircraft, it was concluded that this decline was due to chemical O3 destruction.

  15. Interannual Variability of Ozone in the Polar Vortex during the Fall Season

    NASA Technical Reports Server (NTRS)

    Bhartia, P. K. (Technical Monitor); Kawa, S. R.; Newman, P. A.; Schoeberl, M. R.; Stolarski, R. S.; Bevilacqua, R.

    2002-01-01

    Previous analysis has shown that the distribution of O3 at high northern latitudes in the lower-to-middle stratosphere at the beginning of the winter season has a characteristic distribution, which is consistent between in situ and satellite measurements. Initial O3 profiles in the vortex are similar to each other and are quite different from outside the vortex at the same latitude and also from a zonal mean climatology. In the vortex, O3 is nearly constant from 500 to above 800 K with a value near 3 ppmv. Values outside the vortex are up to a factor of 2 higher and increase significantly with potential temperature. Model analysis indicates that the characteristic vortex O3 profiles arise from a combination of seasonally accelerated photochemical loss at high latitudes and minimal transport of air from lower latitudes. Analysis of the relatively high-resolution POAM data shows that these characteristic O3 distributions are consistent from year to year and between the hemispheres. Here we emphasize analysis of the 24-year time series of O3 data from SBUV in the lower-to-middle stratosphere at high latitudes in the fall vortex. We find that the variability of O3 from SBUV is relatively small in this regime and no significant trend is detectable. The implications of the findings for stratospheric O3 chemistry and transport will be explored.

  16. Synchronous polar winter starphotometry and lidar measurements at a High Arctic station

    NASA Astrophysics Data System (ADS)

    Baibakov, K.; O'Neill, N. T.; Ivanescu, L.; Duck, T. J.; Perro, C.; Herber, A.; Schulz, K.-H.; Schrems, O.

    2015-09-01

    We present recent progress on nighttime retrievals of aerosol and cloud optical properties over the PEARL (Polar Environmental Atmospheric Research Laboratory) station at Eureka (Nunavut, Canada) in the High Arctic (80° N, 86° W). In the spring of 2011 and 2012, a star photometer was employed to acquire aerosol optical depth (AOD) data, while vertical aerosol and cloud backscatter profiles were measured using the CANDAC Raman Lidar (CRL). We used a simple backscatter coefficient threshold (?thr) to distinguish aerosols from clouds and, assuming that aerosols were largely fine mode (FM)/sub-micron, to distinguish FM aerosols from coarse mode (CM)/super-micron cloud or crystal particles. Using prescribed lidar ratios, we computed FM and CM AODs that were compared with analogous AODs estimated from spectral star photometry. We found (?thr dependent) coherences between the lidar and star photometer for both FM events and CM cloud and crystal events with averaged, FM absolute differences being <∼0.03 when associated R2 values were between 0.2 and 0.8. A ?thr sensitivity study demonstrated that zero crossing absolute differences and R2 peaks were in comparable regions of the ?thr range (or physical reasons were given for their disparity). The utility of spectral vs. temporal cloud screening of star photometer AODs was also illustrated. In general our results are critical to building confidence in the physical fidelity of derived, weak amplitude, star photometry AODs and, in turn, towards the development of AOD climatologies and validation databases for polar winter models and satellite sensors.

  17. Connections Between the Spring Breakup of the Southern Hemisphere Polar Vortex, Stationary Waves, and Air-sea Roughness

    NASA Technical Reports Server (NTRS)

    Garfinkel, Chaim I.; Oman, Luke David; Barnes, Elizabeth A.; Waugh, Darryn W.; Hurwitz, Margaret H.; Molod, Andrea M.

    2013-01-01

    A robust connection between the drag on surface-layer winds and the stratospheric circulation is demonstrated in NASA's Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). Specifically, an updated parameterization of roughness at the air-sea interface, in which surface roughness is increased for moderate wind speeds (4ms to 20ms), leads to a decrease in model biases in Southern Hemispheric ozone, polar cap temperature, stationary wave heat flux, and springtime vortex breakup. A dynamical mechanism is proposed whereby increased surface roughness leads to improved stationary waves. Increased surface roughness leads to anomalous eddy momentum flux convergence primarily in the Indian Ocean sector (where eddies are strongest climatologically) in September and October. The localization of the eddy momentum flux convergence anomaly in the Indian Ocean sector leads to a zonally asymmetric reduction in zonal wind and, by geostrophy, to a wavenumber-1 stationary wave pattern. This tropospheric stationary wave pattern leads to enhanced upwards wave activity entering the stratosphere. The net effect is an improved Southern Hemisphere vortex: the vortex breaks up earlier in spring (i.e., the spring late-breakup bias is partially ameliorated) yet is no weaker in mid-winter. More than half of the stratospheric biases appear to be related to the surface wind speed biases. As many other chemistry climate models use a similar scheme for their surface layer momentum exchange and have similar biases in the stratosphere, we expect that results from GEOSCCM may be relevant for other climate models.

  18. Leveraging scientific credibility about Arctic sea ice trends in a polarized political environment

    PubMed Central

    Hall Jamieson, Kathleen; Hardy, Bruce W.

    2014-01-01

    This work argues that, in a polarized environment, scientists can minimize the likelihood that the audience’s biased processing will lead to rejection of their message if they not only eschew advocacy but also, convey that they are sharers of knowledge faithful to science’s way of knowing and respectful of the audience’s intelligence; the sources on which they rely are well-regarded by both conservatives and liberals; and the message explains how the scientist arrived at the offered conclusion, is conveyed in a visual form that involves the audience in drawing its own conclusions, and capsulizes key inferences in an illustrative analogy. A pilot experiment raises the possibility that such a leveraging–involving–visualizing–analogizing message structure can increase acceptance of the scientific claims about the downward cross-decade trend in Arctic sea ice extent and elicit inferences consistent with the scientific consensus on climate change among conservatives exposed to misleadingly selective data in a partisan news source. PMID:25225380

  19. Analysis of the physical state of one Arctic polar stratospheric cloud based on observations

    NASA Technical Reports Server (NTRS)

    Drdla, K.; Tabazadeh, A.; Turco, R. P.; Jacobson, M. Z.; Dye, J. E.; Twohy, C.; Baumgardner, D.

    1994-01-01

    During the Arctic Airborne Stratospheric Expedition (AASE) simultaneous measurements of aerosol size distribution and NO(y)(HN03 + NO + NO2 + 2(N205)) were made along ER-2 flight paths. The flow characteristics of the NO(y) instrument allow us to derive the condensed NO(y) amount (assumed to be HN03) present during polar stratospheric cloud (PSC) events. Analysis of the January 24th flight indicates that this condensed HN03 amount does not agree well with the aerosol volume if the observed PSCs are composed of solid nitric acid trihydrate (NAT), as is generally assumed. However, the composition agrees well with that predicted for liquid H2S04/HN03/H20 solution droplets using a new Aerosol Physical Chemistry Model (APCM). The agreement corresponds in detail to variations in temperature and humidity. The weight percentages of H2SO4, HN03, and H2O derived from the measurements all correspond to those predicted for ternary, liquid solutions.

  20. Analysis of the physical state of one Arctic polar stratospheric cloud based on observations

    SciTech Connect

    Drdla, K.; Tabazadeh, A.; Turco, R.P.; Jacobson, M.Z.; Dye, J.H.; Twohy, C.; Baumgardner, D.

    1994-11-15

    During the Arctic Airborne Stratospheric Expedition, simultaneous measurements of aerosol size distribution and NO{sub y} (HNO{sub 3} + NO + NO{sub 2} + 2{center_dot}N{sub 2}O{sub 5}) were made along ER-2 flight paths. The flow characteristics of the NO{sub y} instrument allow the authors to derive the condensed NO{sub y} amount (assumed to be HNO{sub 3}) present during polar stratospheric cloud (PSC) events. Analysis of the January 24th flight indicates that this condensed HNO{sub 3} amount does not agree well with the aerosol volume if the observed PSCs are composed of solid nitric acid trihydrate (NAT), as is generally assumed. However, the composition agrees well with that predicted for liquid H{sub 2}SO{sub 4}/HNO{sub 3}/H{sub 2}O solution droplets using a new Aerosol Physical Chemistry Model (APCM). The agreement corresponds in detail to variations in temperature and humidity. The weight percentages of H{sub 2}SO{sub 4}, HNO{sub 3}, and H{sub 2}O derived from the measurements all correspond to those predicted for ternary, liquid solutions. 26 refs., 4 figs.

  1. Polar front associated variation in prokaryotic community structure in Arctic shelf seafloor

    PubMed Central

    Nguyen, Tan T.; Landfald, Bjarne

    2015-01-01

    Spatial variations in composition of marine microbial communities and its causes have largely been disclosed in studies comprising rather large environmental and spatial differences. In the present study, we explored if a moderate but temporally permanent climatic division within a contiguous arctic shelf seafloor was traceable in the diversity patterns of its bacterial and archaeal communities. Soft bottom sediment samples were collected at 10 geographical locations, spanning spatial distances of up to 640 km, transecting the oceanic polar front in the Barents Sea. The northern sampling sites were generally colder, less saline, shallower, and showed higher concentrations of freshly sedimented phytopigments compared to the southern study locations. Sampling sites depicted low variation in relative abundances of taxa at class level, with persistent numerical dominance by lineages of Gamma- and Deltaproteobacteria (57–66% of bacterial sequence reads). The Archaea, which constituted 0.7–1.8% of 16S rRNA gene copy numbers in the sediment, were overwhelmingly (85.8%) affiliated with the Thaumarchaeota. Beta-diversity analyses showed the environmental variations throughout the sampling range to have a stronger impact on the structuring of both the bacterial and archaeal communities than spatial effects. While bacterial communities were significantly influenced by the combined effect of several weakly selective environmental differences, including temperature, archaeal communities appeared to be more uniquely structured by the level of freshly sedimented phytopigments. PMID:25667586

  2. A 3D simulation of the early winter distribution of reactive chlorine in the north polar vortex

    SciTech Connect

    Douglass, A.; Rood, R. ); Waters, J.; Froidevaux, L.; Read, W.; Elson, L. ); Geller, M.; Chi, Y. ); Cerniglia, M.; Steenrod, S.

    1993-06-18

    This paper presents the results of 3D simulations of the formation of reactive chlorine on polar stratospheric clouds in the southern polar vortex. The purpose behind these simulations is to compare calculations with measurements of the microwave limb sounder (MLS) carried on the upper atmosphere research satellite (UARS), which showed regions of enhanced ClO in early December 1991, in regions south of areas where temperatures would support the formation of polar stratospheric clouds. The presently accepted model is that reactive chlorine is formed by rapid chemical reactions on the surfaces of particles in polar stratospheric clouds, from gases such as HCl and ClONO[sub 2]. It is then converted to ClO by photochemical processes. The simulations look at cyclonic and anticyclonic circulation patterns in the region of polar stratospheric cloud formation, and the impact this circulation has on the transport of reactive chlorine northward or southward from its creation to regions where it is converted to ClO.

  3. Reconstruction of the constituent distribution and trends in the Antarctic polar vortex from ER-2 flight observations

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.; Lait, Leslie R.; Newman, Paul A.; Martin, Russell L.; Proffitt, Michael H.; Hartmann, Dennis L.; Loewenstein, Max; Podolske, James; Strahan, Susan E.; Gary, Bruce

    1989-01-01

    The measurements of ozone, ClO, and N2O concentrations in the south polar region taken aboard the ER-2 aircraft during the Airborne Antarctic Ozone Experiment are analyzed using conservative coordinate transformations to potential temperature-N2O and potential temperature-potential vorticity space. The latter transformation is equivalent to interpreting trace species observations within the modified Lagrangian mean (MLM) coordinate system. The results show that the MLM transformed ozone concentration decreases at about 0.06 ppmv per day between 20- and 16-km altitude inside the polar vortex during the mid-August to mid-September period. These ozone changes are collocated with the region of high ClO concentration. Outside the chemically perturbed region, at the highest aircraft altitudes, ozone concentration systematically increases, suggesting a diabatic cooling of the order 0.3-0.6 K/day.

  4. Variability of water vapour in the Arctic stratosphere

    NASA Astrophysics Data System (ADS)

    Thölix, L.; Backman, L.; Kivi, R.; Karpechko, A.

    2015-08-01

    This study evaluates the stratospheric water vapour distribution and variability in the Arctic. A FinROSE chemistry climate model simulation covering years 1990-2013 is compared to observations (satellite and frostpoint hygrometer soundings) and the sources of stratospheric water vapour are studied. According to observations and the simulations the water vapour concentration in the Arctic stratosphere started to increase after year 2006, but around 2011 the concentration started to decrease. Model calculations suggest that the increase in water vapour during 2006-2011 (at 56 hPa) is mostly explained by transport related processes, while the photochemically produced water vapour plays a relatively smaller role. The water vapour trend in the stratosphere may have contributed to increased ICE PSC occurrence. The increase of water vapour in the precense of the low winter temperatures in the Arctic stratosphere led to more frequent occurrence of ICE PSCs in the Arctic vortex. The polar vortex was unusually cold in early 2010 and allowed large scale formation of the polar stratospheric clouds. The cold pool in the stratosphere over the Northern polar latitudes was large and stable and a large scale persistent dehydration was observed. Polar stratospheric ice clouds and dehydration were observed at Sodankylä with accurate water vapour soundings in January and February 2010 during the LAPBIAT atmospheric sounding campaign. The observed changes in water vapour were reproduced by the model. Both the observed and simulated decrease of the water vapour in the dehydration layer was up to 1.5 ppm.

  5. Long term changes in the polar vortices

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2015-04-01

    As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented.

  6. On the influence of polar stratospheric cloud formation on chemical composition during the 1988/89 Arctic winter

    SciTech Connect

    Jones, R.L.; McKenna, D.S. ); Poole, L.R. ); Solomon, S. )

    1990-03-01

    The northern winter polar vortex is more disturbed dynamically and warmer than the Antarctic equivalent, and correspondingly fewer polar stratospheric clouds (PSCs) are observed to form. However, the rapid flow of stratospheric air through slow moving synoptically forced PSC regions can result in exposure of both vortical and extra vortical air to PSCs intermittently throughout the winter months. This periodic exposure to PSCs may be sufficient to perturb the chemical composition of large volumes of northern hemisphere air. The synoptic forcing also leads to marked meridional flow which has a profound effect on chemical composition, having major impacts on both short term ozone depletion and the longer term recovery to lower ClOx abundances. Accurate simulation of the air flow is thus essential for the reliable calculation of ozone loss in polar regions.

  7. On the influence of polar stratospheric cloud formation on chemical composition during the 1988/89 Arctic winter

    NASA Technical Reports Server (NTRS)

    Jones, R. L.; Mckenna, D. S.; Poole, L. R.; Solomon, S.

    1990-01-01

    The northern winter polar vortex is more disturbed dynamically and warmer than the Antarctic equivalent, and correspondingly fewer polar stratospheric clouds (PSCs) are observed to form. However, the rapid flow of stratospheric air through slow moving synoptically forced PSC regions can result in exposure of both vortical and extra vortical air to PSCs intermittently throughout the winter months. This periodic exposure to PSCs may be sufficient to perturb the chemical composition of large volumes of nothern hemisphere air. The synoptic forcing also leads to marked meridional flow which has a profound effect on chemical composition, having major impacts on both short term ozone depletion and the longer term recovery to lower ClOx abundances. Accurate simulation of the air flow is thus essential for the reliable calculation of ozone loss in polar regions.

  8. Arctic chemical Ozone Loss Observed by the AROTEL Instrument during the SOLVE Campaign, December 1999 - March 2000

    NASA Technical Reports Server (NTRS)

    McGee, Thomas J.; Burris, John F.; Hoegy, Walter; Newman, Paul; Heaps,William; Silbert, Donald; Lait, Leslie; Sumnicht, Grant; Twigg, Laurence

    2000-01-01

    During the winter of 1999-2000, the AROTEL instrument was deployed on the NASA DC-8 at Kiruna, Sweden for the SAGE III Ozone Loss Validation Experiment (SOLVE). Measurements of ozone, temperature and aerosols were made on 18 local science flights from December to March. Extremely low temperatures were observed throughout most of the Arctic vortex and polar stratospheric clouds were observed throughout the Arctic area during January. Significant ozone loss was measured after the sun began to rise on the vortex area in February. Ozone mixing ratios as low as 800 ppbv were observed during flights in March.

  9. Subsidence, Mixing and Denitrification of Polar Vortex Air Measured During Polaris

    NASA Technical Reports Server (NTRS)

    Rex, M.; Salawitch, R.; Toon, G.; Sen, B.; Margitan, J.; Osterman, G.; Blavier, J.; Gao, R.; Del Negro, L.; Donnelly, S.; Keim, E.; Neuman, J.; Fahey, D.; Webster, C.; Scott, D.; Herman, B.; May, R.; Moyer, L.; Gunson, M.; Irion, F.; Chang, A.; Rinsland, R.; Bui, P.; Loewenstein, M.

    1998-01-01

    We use the correlation between CH(sub 4) and N(sub 2)O as measured during the POLARIS campaign in spring 1997 to estimate the degree of mixing between descended air masses from the vortex and air masses from mid-latitudes.

  10. ArtArctic Science: a polarTREC effort to educate about Antarctica through art

    NASA Astrophysics Data System (ADS)

    Botella, J.; Racette, B.

    2013-12-01

    Formal scientific education is as important as ever for raising awarness about Antarctic issues, but some people resistance to learning about scienctific issues demands novel approaches for reaching people who are not in the classroom. ArtArctic Science is an interactive exhibit of photography and paintings presented at the Overture Center for the Arts, in Madison, WI by Monona Grove High School students and a science teacher that attempts to educate the general audience about Antarctic science. The exhibit explores art as a form of perceiving and understanding the world around us, and as a way of igniting the spark of curiosity that can lead to scientific inquiries. Antarctica has inspired explorers and scientists for over 100 years, and we add our work to efforts that share scientific results with common people. Antarctica offers stunning views of amazing geometric ice structures complemented and contrasted by the organisms that inhabit it that fascinate most everyone. We probe these scenes through photography and paintings knowing that there is more in each image than what the eye can 'see'. We invite the viewer to discover these secrets by engaging the observer in a mimicking of the scientific method (observation, questioning, finding an explanation, revising the explanation). Each art piece has a question and a scientific explanation hidden under a wooden lid. The observer is invited to explore the scene, involve itself with the scientific query, come up with an answer, and compare his or her idea with the hidden explanation. The exhibit is inspired by an Antarctic PolarTREC expedition in which our science teacher participated as a member of a scientific research team. In this presentation we share the knowledge acquired through this experience in hopes that it will help others attempting a similar Project.

  11. Polar Gateways Arctic Circle Sunrise Conference 2008, Barrow, Alaska: IHY-IPY Outreach on Exploration of Polar and Icy Worlds in The Solar System

    NASA Astrophysics Data System (ADS)

    Cooper, John F.; Kauristie, K.; Weatherwax, A. T.; Sheehan, G. W.; Smith, R. W.; Sandahl, I.; Østgaard, N.; Chernouss, S.; Moore, M. H.; Peticolas, L. M.; Senske, D. A.; Thompson, B. J.; Tamppari, L. K.; Lewis, E. M.

    2008-09-01

    Polar, heliophysical, and planetary science topics related to the International Heliophysical and Polar Years 2007-2009 were addressed during this circumpolar video conference hosted January 23-29, 2008 at the new Barrow Arctic Research Center of the Barrow Arctic Science Consortium in Barrow, Alaska. This conference was planned as an IHY-IPY event science outreach event bringing together scientists and educational specialists for the first week of sunrise at subzero Arctic temperatures in Barrow. Science presentations spanned the solar system from the polar Sun to Earth, Moon, Mars, Jupiter, Saturn, and the Kuiper Belt. On-site participants experienced look and feel of icy worlds like Europa and Titan by being in the Barrow tundra and sea ice environment and by going "on the ice" during snowmobile expeditions to the near-shore sea ice environment and to Point Barrow, closest geographic point in the U.S. to the North Pole. Many science presentations were made remotely via video conference or teleconference from Sweden, Norway, Russia, Canada, Antarctica, and the United States, spanning up to thirteen time zones (Alaska to Russia) at various times. Extensive educational outreach activities were conducted with the local Barrow and Alaska North Slope communities and through the NASA Digital Learning Network live from the "top of the world" at Barrow. The Sun-Earth Day team from Goddard, and a videographer from the Passport to Knowledge project, carried out extensive educational interviews with many participants and native Inupiaq Eskimo residents of Barrow. Video and podcast recordings of selected interviews are available at http://sunearthday.nasa.gov/2008/multimedia/podcasts.php. Excerpts from these and other interviews will be included in a new high definition video documentary called "From the Sun to the Stars: The New Science of Heliophysics" from Passport to Knowledge that will later broadcast on NASA TV and other educational networks. Full conference proceedings are accessible at http://polargateways2008.org/.

  12. Polar Gateways Arctic Circle Sunrise Conference 2008, Barrow, Alaska: IHY-IPY Outreach on Exploration of Polar and Icy Worlds in the Solar System

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Kauristie, Kirsti; Weatherwax, Allan T.; Sheehan, Glenn W.; Smith, Roger W.; Sandahl, Ingrid; Ostgaard, Nikolai; Chernouss, Sergey; Thompson, Barbara J.; Peticolas, Laura; Moore, Marla H.; Senske, David A.; Tamppari, Leslie K.; Lewis, Elaine M.

    2008-01-01

    Polar, heliophysical, and planetary science topics related to the International Heliophysical and Polar Years 2007-2009 were addressed during this circumpolar video conference hosted January 23-29, 2808 at the new Barrow Arctic Research Center of the Barrow Arctic Science Consortium in Barrow, Alaska. This conference was planned as an IHY-IPY event science outreach event bringing together scientists and educational specialists for the first week of sunrise at subzero Arctic temperatures in Barrow. Science presentations spanned the solar system from the polar Sun to Earth, Moon, Mars, Jupiter, Saturn, and the Kuiper Belt. On-site participants experienced look and feel of icy worlds like Europa and Titan by being in the Barrow tundra and sea ice environment and by going "on the ice" during snowmobile expeditions to the near-shore sea ice environment and to Point Barrow, closest geographic point in the U.S. to the North Pole. Many science presentations were made remotely via video conference or teleconference from Sweden, Norway, Russia, Canada, Antarctica, and the United States, spanning up to thirteen time zones (Alaska to Russia) at various times. Extensive educational outreach activities were conducted with the local Barrow and Alaska North Slope communities and through the NASA Digital Learning Network live from the "top of the world" at Barrow. The Sun- Earth Day team from Goddard, and a videographer from the Passport to Knowledge project, carried out extensive educational interviews with many participants and native Inupiaq Eskimo residents of Barrow. Video and podcast recordings of selected interviews are available at http://sunearthday.nasa.gov/2008/multimedidpodcasts.php. Excerpts from these and other interviews will be included in a new high definition video documentary called "From the Sun to the Stars: The New Science of Heliophysics" from Passport to Knowledge that will later broadcast on NASA TV and other educational networks. Full conference proceedings are accessible at http://polargateways2008.org/.

  13. Chlorine Partitioning in the Arctic Vortex During Winter 1995 Derived From Submillimeterwave Remote Sensing and in Situ Constituent Measurements

    NASA Technical Reports Server (NTRS)

    Stachnik, R. A.; Hardy, J. C.; Engel, A.; Schmidt, U.

    1995-01-01

    High altitude balloon flights of a combined payload of the Submillimeterwave Limb Sounder and the whole air sampler instruments were performed on 27 January 1995 and 08 March 1995. Both flights were launched from sweden as part of the Second European Stratospheric Arctic and Mid-latitude Experiment (SESAME). Results of the first flight suggest that most of the available chlorine had been converted to CLOx in the observed air parcel, while warmer air in the second flight had much more HCl than CLOx.

  14. Airborne measurements of stratospheric constituents over the Arctic in the winter of 1989

    SciTech Connect

    Mankin, W.G.; Coffey, M.T.; Goldman, A. ); Schoeberl, M.R.; Lait, L.R.; Newman, P.A. )

    1990-03-01

    The authors have used a Fourier transform spectrometer aboard the NASA DC-8 aircraft during the Airborne Arctic Stratospheric Expedition (AASE) to record infrared absorption spectra of the polar stratosphere. From these high resolution spectra the authors have derived vertical column amounts above flight altitude of O{sub 3}, CH{sub 4}, N{sub 2}O, HCl, HF, NO, NO{sub 2}, ClONO{sub 2}, and HNO{sub 3} for eleven flights poleward of 60{degree}N. The authors report here measurements on the flight of 26 January 1989 when the flight path during the observations crossed from outside the polar vortex to inside. This allowed a clear comparison of the conditions of the air within the vortex with that outside. Observations of passive tracers such as CH{sub 4} and HF indicate that air of a certain composition within the polar vortex occurs at lower altitude than air outside. Within the vortex, they observed markedly reduced columns of HCl and NO{sub 2}. The ratio of HCl to HF column dropped from its typical midlatitude value of 4.5 to as low as 1.7 within the vortex, implying that the HCl had been chemically or physically removed from the air in the vortex. NO{sub 2} values within the vortex were near 3.0{times}10{sup 14} molecules-cm{sup {minus}2}, about a factor of two less than columns outside. In contrast to the Antarctic observations, HNO{sub 3} values were elevated within the vortex. HNO{sub 3} columns inside the vortex reached values of 30{times}10{sup 15} molecules-cm{sup {minus}2}. The ClONO{sub 2} column was largest within the vortex, peaking at 4{times}10{sup 15} molecules-cm{sup {minus}2} near the boundary of the vortex, and decreasing farther into the vortex.

  15. Archaeal Ammonia Oxidizers and Total Production of N2O and CH4 in Arctic Polar Desert Soils

    NASA Astrophysics Data System (ADS)

    Brummell, Martin; Robert, Stan; Bodrossy, Levente; Abell, Guy; Siciliano, Steven

    2014-05-01

    Ammonia-oxidizing Archaea are abundant in Arctic desert soils and appear to be responsible for the majority of ammonia oxidation activity in these cold and dry ecosystems. We used DNA microarrays to characterize the microbial community consisting of ammonia-oxidizing Archaea and methane-oxidizing Bacteria in three polar deserts from Ellesmere Island, Canada. Patterns of net greenhouse gas production, including production and consumption of CO2, CH4, and N2O were compared with community relative richness and abundance in a structural equation model that tested causal hypotheses relating edaphic factors to the biological community and net gas production. We extracted and amplified DNA sequences from soils collected at three polar deserts on Ellesmere Island in the Canadian high Arctic, and characterized the community structure using DNA microarrays. The functional genes Archaeal AmoA and pMMO were used to compare patterns of biological community structure to the observed patterns of net greenhouse gas production from those soils, as measured in situ. Edaphic factors including water content, bulk density, pH, and nutrient levels such as nitrate, ammonia, and extractable organic carbon were also measured for each soil sample, resulting in a highly multivariate dataset. Both concentration and net production of the three greenhouse gases were correlated, suggesting underlying causal factors. Edaphic factors such as soil moisture and pH had important, direct effects on the community composition of both functional groups of microorganisms, and pH further had a direct effect on N2O production. The structural relationship between the examined microbial communities and net production of both N2O and CH4 was strong and consistent between varying model structures and matrices, providing high confidence that this model relationship accurately reflects processes occurring in Arctic desert soils.

  16. Arctic Ocean circulation, processes and water masses: A description of observations and ideas with focus on the period prior to the International Polar Year 2007-2009

    NASA Astrophysics Data System (ADS)

    Rudels, Bert

    2015-03-01

    The evolving knowledge of the Arctic Ocean, its hydrography and its water masses and their transformations and circulation is reviewed starting with the observations made on Fram 1893-1896 and extending to the International Polar Year (IPY) 2007-2009. The expeditions and observations after Fram to the mid 20th century as well as the more extensive and systematic studies of water masses and circulation made from ice stations and airborne expeditions from the late 1940s to the late 1970s are briefly described. The early concepts of the connections and exchanges between the Arctic Ocean and the world ocean are also discussed. In the 1980s scientific icebreakers were beginning to enter the inner parts of the Arctic Ocean and large international programmes were launched, culminating in the IPY. The changes in the Arctic Ocean, first noted in the Atlantic layer in 1990 and shortly after in the upper layers, are described. The exchanges between the Arctic Ocean and the surrounding seas through the four main openings, Fram Strait, Barents Sea, Bering Strait and the Canadian Arctic Archipelago as well the volume and freshwater balances of the Arctic Ocean are examined.

  17. The impacts of volcanic aerosol on stratospheric ozone and the Northern Hemisphere polar vortex: separating radiative-dynamical changes from direct effects due to enhanced aerosol heterogeneous chemistry

    NASA Astrophysics Data System (ADS)

    Muthers, S.; Arfeuille, F.; Raible, C. C.; Rozanov, E.

    2015-10-01

    After major volcanic eruptions the enhanced aerosol causes ozone changes due to greater heterogeneous chemistry on the particle surfaces (HET-AER) and from dynamical effects related to the radiative heating of the lower stratosphere (RAD-DYN). We carry out a series of experiments with an atmosphere-ocean-chemistry-climate model to assess how these two processes change stratospheric ozone and Northern Hemispheric (NH) polar vortex dynamics. Ensemble simulations are performed under present day and preindustrial conditions, and with aerosol forcings representative of different eruption strength, to investigate changes in the response behaviour. We show that the halogen component of the HET-AER effect dominates under present-day conditions with a global reduction of ozone (-21 DU for the strongest eruption) particularly at high latitudes, whereas the HET-AER effect increases stratospheric ozone due to N2O5 hydrolysis in a preindustrial atmosphere (maximum anomalies +4 DU). The halogen-induced ozone changes in the present-day atmosphere offset part of the strengthening of the NH polar vortex during mid-winter (reduction of up to -16 m s-1 in January) and slightly amplify the dynamical changes in the polar stratosphere in late winter (+11 m s-1 in March). The RAD-DYN mechanism leads to positive column ozone anomalies which are reduced in a present-day atmosphere by amplified polar ozone depletion (maximum anomalies +12 and +18 DU for present day and preindustrial, respectively). For preindustrial conditions, the ozone response is consequently dominated by RAD-DYN processes, while under present-day conditions, HET-AER effects dominate. The dynamical response of the stratosphere is dominated by the RAD-DYN mechanism showing an intensification of the NH polar vortex in winter (up to +10 m s-1 in January). Ozone changes due to the RAD-DYN mechanism slightly reduce the response of the polar vortex after the eruption under present-day conditions.

  18. Monitoring the Seasonal Evolution of the North and South Polar Vortex on Titan during 10 Years with Cassini/Vims

    NASA Astrophysics Data System (ADS)

    Le Mouelic, S.; Rousseau, B.; Rodriguez, S.; Cornet, T.; Sotin, C.; Barnes, J. W.; Brown, R. H.; Buratti, B. J.; Baines, K. H.; Clark, R. N.; Nicholson, P. D.

    2014-12-01

    Cassini entered in Saturn's orbit in July 2004. In ten years, more than 100 targeted flybys of Titan have been performed. We focus our study on the comprehensive analysis of the Visual and Infrared Mapping Spectrometer data set acquired between 2004 and 2014, with a particular emphasis on the atmospheric polar features. First evidences for a vast ethane cloud covering the North Pole have been detected as soon as the second targeted flyby in December 2005 [1]. The first detailed imaging of this north polar feature with VIMS was obtained in December 2006, thanks to a change in inclination of the spacecraft orbit [2]. At this time, the northern lakes and seas of Titan were totally masked to the optical instruments by the haze and clouds, whereas the southern pole was well illuminated and mostly clear of haze and vast clouds. Subsequent flybys revealed that the vast north polar feature was progressively vanishing around the equinox in 2009 [2,3,4], in agreement with the predictions of Global Circulation Models [5]. It revealed progressively the underlying lakes to the ISS and VIMS instruments. First evidences of an atmospheric vortex growing over the South Pole occurred in May 2012, with a high altitude feature detected at each flybys since then. In this study, we have computed individual global maps of the north and south poles for each of the 100 targeted flybys, using VIMS wavelengths sensitive both to clouds and surface features. This allows a more complete monitoring of the evolution of the north polar cloud than was previously done before using a selection of individual flybys only. It also provides a detailed investigation of what is currently acting over the South Pole. [1] Griffith et al., Science, 2006. [2] Le Mouélic et al., PSS, 2012. [3] Rodriguez et al., Nature, 2009. [4] Rodriguez et al., Icarus 2011. [5] Rannou et al., Science 2005

  19. Arctic Amplification and Potential Mid-Latitude Weather Linkages

    NASA Astrophysics Data System (ADS)

    Overland, J. E.

    2014-12-01

    Increasing temperatures and other changes continued in the Arctic over the last decade, even though the rate of global warming has decreased in part due to a cool Pacific Ocean. Thus Arctic temperatures have increased at least 3 times the rate of mid-latitude temperatures. Credibility for persistent Arctic change comes from multiple indicators which are now available for multiple decades. Further, the spatial pattern of Arctic Amplification differs from patterns of natural variability. The role of the Arctic in the global climate system is based on multiple interacting feedbacks represented by these indicators as a causal basis for Arctic Amplification driven by modest global change. Many of these processes act on a regional basis and their non-linear interactions are not well captured by climate models. For example, future loss of sea ice due to increases in CO2 are demonstrated by these models but the rates of loss appear slow. It is reasonable to suspect that Arctic change which can produce the largest temperature anomalies on the planet and demonstrate recent extremes in the polar vortex could be linked to mid-latitude weather, especially as Arctic change will continue over the next decades. The meteorological community remains skeptical, however, in the sense of "not proven." Natural variability in chaotic atmospheric flow remains the main dynamic process, and it is difficult to determine whether Arctic forcing of a north-south linkage is emerging from the most recent period of Arctic change since 2007. Nonetheless, such a hypothesis is worthy of investigation, given the need to further understand Arctic dynamic atmospheric processes, and the potential for improving mid-latitude seasonal forecasts base on high-latitude forcing. Several AGU sessions and other forums over the next year (WWRP, IASC,CliC) address this issue, but the topic is not ready for a firm answer. The very level of controversy indicates the state of the science.

  20. Resolution and contrast enhancement of subtractive second harmonic generation microscopy with a circularly polarized vortex beam

    PubMed Central

    Tian, Nian; Fu, Ling; Gu, Min

    2015-01-01

    We extend the subtractive imaging method to label-free second harmonic generation (SHG) microscopy to enhance the spatial resolution and contrast. This method is based on the intensity difference between two images obtained with circularly polarized Gaussian and doughnut-shaped beams, respectively. By characterizing the intensity and polarization distributions of the two focused beams, we verify the feasibility of the subtractive imaging method in polarization dependent SHG microscopy. The resolution and contrast enhancement in different biological samples is demonstrated. This work will open a new avenue for the applications of SHG microscopy in biomedical research. PMID:26364733

  1. Resolution and contrast enhancement of subtractive second harmonic generation microscopy with a circularly polarized vortex beam

    NASA Astrophysics Data System (ADS)

    Tian, Nian; Fu, Ling; Gu, Min

    2015-09-01

    We extend the subtractive imaging method to label-free second harmonic generation (SHG) microscopy to enhance the spatial resolution and contrast. This method is based on the intensity difference between two images obtained with circularly polarized Gaussian and doughnut-shaped beams, respectively. By characterizing the intensity and polarization distributions of the two focused beams, we verify the feasibility of the subtractive imaging method in polarization dependent SHG microscopy. The resolution and contrast enhancement in different biological samples is demonstrated. This work will open a new avenue for the applications of SHG microscopy in biomedical research.

  2. The International Polar Year, 2007-2008, an opportunity to focus on infectious diseases in Arctic regions.

    PubMed

    Parkinson, Alan J

    2008-01-01

    On 3 occasions over the past 125 years, scientists from around the world have worked together to organize scientific and exploration activities in polar regions (www.ipy.org). The first International Polar Year (IPY) in 1881-1884 marked the first major coordinated international scientific initiative to collect standardized meteorological and geophysical data in polar regions. Fifteen expeditions led by 12 nations amassed a large amount of data, but the scientific value was diminished by disjointed publication efforts and lack of long-term institutional commitment; lessons were learned and corrected in subsequent polar years. The second IPY began in 1932. Forty-four nations led expeditions in the Arctic and Antarctic, resulting in greater understanding of the aurora, magnetism, and meteorology. Air and marine navigation, radio operations, and weather forecasting were greatly improved as a result. The third IPY, in 1957-58, was renamed the International Geophysical Year and capitalized on technologic advances developed during World War II. Technologic and scientific momentum was redirected toward research, particularly to studies of the upper atmosphere, a legacy that continues to the present day. Notable achievements included launching the first satellite, measurement of atmospheric greenhouse gases, delineating the system of mid-ocean ridges, and confirming the theory of plate tectonics. PMID:18258069

  3. Quantifying the response strength of the southern stratospheric polar vortex to Indian Ocean warming in austral summer

    NASA Astrophysics Data System (ADS)

    Li, Shuanglin; Chen, Xiaoting

    2014-03-01

    A previous multiple-AGCM study suggested that Indian Ocean Warming (IOW) tends to warm and weaken the southern polar vortex. Such an impact is robust because of a qualitative consistency among the five AGCMs used. However, a significant difference exists in the modeled strengths, particularly in the stratosphere, with those in three of the AGCMs (CCM3, CAM3, and GFS) being four to five times as strong as those in the two other models (GFDL AM2, ECHAM5). As to which case reflects reality is an important issue not only for quantifying the role of tropical ocean warming in the recent modest recovery of the ozone hole over the Antarctic, but also for projecting its future trend. This issue is addressed in the present study through comparing the models' climatological mean states and intrinsic variability, particularly those influencing tropospheric signals to propagate upward and reach the stratosphere. The results suggest that differences in intrinsic variability of model atmospheres provide implications for the difference. Based on a comparison with observations, it is speculated that the impact in the real world may be closer to the modest one simulated by GFDL AM2 and ECHAM5, rather than the strong one simulated by the three other models (CCM3, CAM3 and GFS). In particular, IOW during the past 50 years may have dynamically induced a 1.0°C warming in the polar lower stratosphere (˜ 100 hPa), which canceled a fraction of radiative cooling due to ozone depletion.

  4. Observational Evidence Against Mountain-Wave Generation of Ice Nuclei as a Prerequisite for the Formation of Three Solid Nitric Acid Polar Stratospheric Clouds Observed in the Arctic in Early December 1999

    NASA Technical Reports Server (NTRS)

    Pagan, Kathy L.; Tabazadeh, Azadeh; Drdla, Katja; Hervig, Mark E.; Eckermann, Stephen D.; Browell, Edward V.; Legg, Marion J.; Foschi, Patricia G.

    2004-01-01

    A number of recently published papers suggest that mountain-wave activity in the stratosphere, producing ice particles when temperatures drop below the ice frost point, may be the primary source of large NAT particles. In this paper we use measurements from the Advanced Very High Resolution Radiometer (AVHRR) instruments on board the National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites to map out regions of ice clouds produced by stratospheric mountain-wave activity inside the Arctic vortex. Lidar observations from three DC-8 flights in early December 1999 show the presence of solid nitric acid (Type Ia or NAT) polar stratospheric clouds (PSCs). By using back trajectories and superimposing the position maps on the AVHRR cloud imagery products, we show that these observed NAT clouds could not have originated at locations of high-amplitude mountain-wave activity. We also show that mountain-wave PSC climatology data and Mountain Wave Forecast Model 2.0 (MWFM-2) raw hemispheric ray and grid box averaged hemispheric wave temperature amplitude hindcast data from the same time period are in agreement with the AVHRR data. Our results show that ice cloud formation in mountain waves cannot explain how at least three large scale NAT clouds were formed in the stratosphere in early December 1999.

  5. Stratospheric trace gas concentrations in the Arctic Polar night derived by FTIR-spectroscopy with the moon as IR light source

    SciTech Connect

    Notholt, J.; Neuber, R.; Schrems, O.; Clarmann, T.V.

    1993-10-08

    This article reports measurements of column densities of trace gas concentrations within the polar vortex by means of an FTIR instrument using moon light as a light source. N[sub 2]O, CH[sub 4], HF, HCl, O[sub 3], NO[sub 2], HNO[sub 3], and ClONO[sub 2] were measured, and correlated with the observation of polar stratospheric clouds, which appeared at several times during the observation period.

  6. The Earth Is Faster Now: Indigenous Observations of Arctic Environmental Change. Frontiers in Polar Social Science.

    ERIC Educational Resources Information Center

    Krupnik, Igor, Ed.; Jolly, Dyanna, Ed.

    This book focuses on documenting and understanding the nature of environmental changes observed by indigenous residents of the Arctic. Common themes include increasing variability and unpredictability of the weather and seasonal climatic patterns, as well as changes in the sea ice and the health of wildlife. Nine papers focus on these changes,…

  7. Remote-sensing measurements in the polar vortex: Comparison to in situ observations and implications for the simultaneous retrievals and analysis of the NO2 and OClO species

    NASA Astrophysics Data System (ADS)

    Berthet, G.; Renard, J.-B.; Catoire, V.; Chartier, M.; Robert, C.; Huret, N.; Coquelet, F.; Bourgeois, Q.; RivièRe, E. D.; Barret, B.; LefèVre, F.; Hauchecorne, A.

    2007-11-01

    Nighttime remote-sensing balloon observations conducted by the SALOMON instrument in the arctic polar vortex in January 2006 reveal high amounts of stratospheric NO2 in the lower stratosphere similarly to previously published profiles. NO2 concentration enhancements are also present in the vertical profiles observed by the GOMOS instrument on board the Envisat satellite and obtained coincidently to the balloon measurements. Such quantities are not present in in situ observations obtained by the SPIRALE instrument in similar geophysical conditions. While OClO amounts are acceptably reproduced by Chemistry Transport Model (CTM) calculations, NO2 simulated values are well below the observed quantities. The examination of the slant column densities of NO2 obtained at float altitude highlights unexpected strong enhancements with respect to the elevation angle and displacement of the balloon. It is shown that these fluctuations result from NO2 spatial inhomogeneities located above the balloon float altitude. Potential vorticity maps reveal the presence of midlatitude NO2-rich air in the upper stratosphere or lower mesosphere as a result of the perturbed dynamical situation of the vortex. The presence of spatial inhomogeneities crossed by the lines of sight leads to artificial high concentration values of NO2 in the vertical profile retrieved from the slant column densities assuming spatial homogeneity. A direct implication is that the differences previously observed between measurements of NO2 and OClO and model results are probably mostly due to the improper inversion of NO2 in the presence of perturbed dynamical conditions or when mesospheric NOx production events occur. The dynamical situation will have to be systematically analyzed in future studies involving remote-sensing observations.

  8. POLAR-UVI and other Coordinated Observations of a Traveling Convection Vortex Event Observed on 24 July 1996

    NASA Technical Reports Server (NTRS)

    Clauer, C. R.; Baker, J. B.; Ridley, A. J.; Sitar, R. J.; Papitashvili, V. O.; Cumnock, J.; Spann, J. F., Jr.; Brittnacher, M. J.; Parks, G. K.

    1997-01-01

    Coordinated analysis of data from the POLAR UVI instrument, ground magnetometers, incoherent scatter radar, solar wind monitors IMP-8 and WIND, and DMSP satellite is focused on a traveling convection vortex (TCV) event on 24 July 1966. Starting at 10:48 UT, ground magnetometers in Greenland and eastern Canada measure pulsations consistent with the passing overhead of a series of alternating TCV field-aligned current pairs. Sondrestrom incoherent scatter radar measures strong modulation of the strength and direction of ionospheric plasma flow, The magnetometer pulsations grow in magnitude over the next hour, peaking in intensity at 11:39 UT, at which time the UVI instrument measures a localized intensification of auroral emissions over central and western Greenland. Subsequent images show the intensification grow in strength and propagate westward (tailward) until approximately 11:58 UT at which time the emissions fade. These observations are consistent with the westward passage of two pairs of moderately intense TCVs over central Greenland followed by a third very intense TCV pair. The intensification of auroral emissions at 11:39 UT is associated with the trailing vortex of the third TCV pair, thought to be the result of an upward field-aligned current. Measurements of the solar wind suggest that a pressure change may be responsible for triggering the first two pairs of TCVS, and that a subsequent sudden change in orientation of the IMF may have produced the intensification of the third TCV pair and the associated aurora] brightening. DMSP particle data indicate that the TCVs occur on field lines which map to the boundary plasma sheet or outer edge of the low latitude boundary layer.

  9. Airborne measurements of stratospheric constituents over the Arctic in the winter of 1989

    NASA Technical Reports Server (NTRS)

    Mankin, William G.; Coffey, M. T.; Goldman, Aaron; Schoeberl, Mark R.; Lait, Leslie R.; Newman, Paul A.

    1990-01-01

    A Fourier transform spectrometer aboard the NASA DC-8 aircraft was used during the Airborne Arctic Stratospheric Expedition (AASE) to record infrared absorption spectra of the polar stratosphere. From these high resolution spectra, vertical column amounts above flight altitude were derived of O3, CH4, N2O, H2O, HCl, HF, NO, NO2, ClONO2, and HNO3 for eleven flights poleward of 60 deg N. In this paper, measurements on the flight of January 26, 1989 were derived when the flight path during the observations crossed from outside the polar vortex to inside. This allowed a clear comparison of the conditions of the air within the vortex with that outside. Observations of passive tracers such as CH4 and HF indicate that air of a certain composition within the polar vortex occurs at lower altitude than air outside. Within the vortex, markedly reduced columns of HCl and NO2. The ratio of HCl to HF column dropped from its typical midlatitude value of 4.5 to as low as 1.7 within the vortex, implying that the HCl had been chemically or physically removed from the air in the vortex. In contrast to the Antarctic observations, HNO3 values were elevated within the vortex.

  10. Arctic technology and policy

    SciTech Connect

    Dyer, I.; Chryssostomidis, C.

    1984-01-01

    Topics covered include: legal regime of the arctic, including national and international legal frameworks that govern arctic resource development; environmental policy and socio-economic issues, focusing on the political and economic considerations of LNG transport in icebound waterways; risk and safety assessment for arctic offshore projects, drilling systems for the arctic; arctic offshore technology, including island, steel, and concrete structures; icebreaking technology, focusing on the current state of the art and indicating future research areas; arctic oceanography, summarizing characteristics of ice from field experiments pertaining to the design of structures, ships, and pipelines; arctic seismic exploration, detailing signal processes for underwater communication in the context of arctic geology and geophysics; ice morphology, providing information about ice shapes, particularly critical to the determination of overall strength of ice masses; remote sensing; modeling of arctic ice fields, including information about the design and construction of offshore facilities in polar areas; and engineering properties of ice, providing theoretical and experimental studies.

  11. Distribution and inventories of polychlorinated biphenyls in the polar mixed layer of seven pan-arctic shelf seas and the interior basins.

    PubMed

    Carrizo, Daniel; Gustafsson, Örjan

    2011-02-15

    Assessment of the Arctic as a global repository of polychlorinated biphenyls (PCBs) and of uptake processes in the base of its marine food chain hinges on reliable information of PCB distribution in surface seawater, yet there is a scarcity of quality-assured PCB measurements in this key compartment. Here, surface seawater PCB concentrations and congener fingerprints are evaluated for all seven pan-Arctic shelf seas and for the interior basins. Particulate and dissolved PCBs were collected via trace-clean protocols on three basin-wide expeditions (AO-01, Beringia-2005, and ISSS-08). Concentrations of the sum of 13 abundant congeners (?13PCB) were 0.13-21 pg/L, with higher concentrations in the shelf seas and lower concentrations in the Central Arctic Basin. Trichlorinated PCBs constituted about half of the total loadings in the Eastern Arctic (Beaufort, Chukchi, East Siberian, and Laptev Seas) and in the Central Basin, indicating an atmospheric source. In contrast, hexachlorinated PCBs were more abundant than tri-PCBs in the western sector, suggesting a role also for waterborne transport from regions of heavy PCB consumption in North America and Europe. Finally, the inventory of ?13PCB in the polar mixed layer of the entire Arctic Ocean was 0.39 ton, which implies that only 0.0008% of historical PCB emissions are now residing in Arctic surface waters. PMID:21222432

  12. Lidar Measurements of Aerosol and Ozone Distributions During the 1992 Airborne Arctic Stratospheric Expedition

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Butler, C. F.; Fenn, M. A.; Grant, W. B.; Carter, A. F.

    1992-01-01

    The LaRC airborne lidar system was operated from the ARC DC-8 aircraft during the 1992 Airborne Arctic Stratospheric Expedition (ASEE-2) to investigate the distribution of stratospheric aerosols and O3 across the Arctic vortex from Jan. to Mar. 1992. Monthly flights were made across the Arctic vortex from Anchorage, Alaska, to Stavanger, Norway, and then back to Bangor, Maine, and additional round-trip flights north into the vortex were made each month from either Stavanger or Bangor depending on the location of the vortex that month. The airborne lidar system uses the differential absorption lidar (DIAL) technique at laser wavelengths of 301.5 and 310.8 nm to measure O3 profiles above the DC-8 over the 12-25 km altitude range. Lidar measurements of aerosol backscatter and depolarization profiles over the 12-30 km altitude range are made simultaneously with the O3 measurements using infrared (IR) and visible (VIS) laser wavelengths of 603 and 1064 nm, respectively. The measurements of Pinatubo aerosols, polar stratospheric clouds, and O3 made with the airborne DIAL system during the AASE-2 expedition and to chemical and dynamical process that contribute to O3 depletion in the wintertime Arctic stratosphere.

  13. Future Arctic temperature and ozone: The role of stratospheric composition changes

    NASA Astrophysics Data System (ADS)

    Langematz, Ulrike; Meul, Stefanie; Grunow, Katja; Romanowsky, Erik; Oberländer, Sophie; Abalichin, Janna; Kubin, Anne

    2014-03-01

    Using multidecadal simulations with the European Centre/Hamburg-Modular Earth Submodel System Atmospheric Chemistry (EMAC) model, the role of changing concentrations of ozone-depleting substances (ODSs) and greenhouse gases (GHGs) on Arctic springtime ozone was examined. The focus is on potential changes in the meteorological conditions relevant for Arctic ozone depletion. It is found that with rising GHG levels the lower Arctic stratosphere will cool significantly in early winter, while no significant temperature signal is identified later in winter or spring. A seasonal shift of the lowest polar minimum temperatures from late to early winter in the second part of the 21st century occurs. However, Arctic lower stratosphere temperatures do not seem to decline to new record minima. The future Arctic lower stratosphere vortex will have a longer lifetime, as a result of an earlier formation in autumn. No extended vortex persistence is found in spring due to enhanced dynamical warming by tropospheric wave forcing. Because of the dominant early winter cooling, largest accumulated polar stratospheric cloud (PSC) areas (APSC) are projected for the middle of the 21st century. A further increase of APSC toward the end of the 21st century is prevented by increased dynamical polar warming. EMAC suggests that in the near future, there is a chance of low Arctic springtime ozone in individual years; however, there is no indication of a formation of regular Arctic ozone holes. Toward the end of the 21st century, when ODSs will be close to the 1960 levels, further rising GHG levels will cause increased Arctic springtime ozone.

  14. Radiative effects of polar stratospheric clouds during the Airborne Antarctic Ozone Experiment and the Airborne Arctic Stratospheric Expedition

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.

    1992-01-01

    Results are presented of a study of the radiative effects of polar stratospheric clouds during the Airborne Antarctic Ozone Experiment (AAOE) and the Airborne Arctic Stratospheric Expedition (AASE) in which daily 3D Type I nitric acid trihydrate (NAT) and Type II water ice polar stratospheric clouds (PSCs) were generated in the polar regions during AAOE and the AASE aircraft missions. Mission data on particular composition and size, together with NMC-analyzed temperatures, are used. For AAOE, both Type I and Type II clouds were formed for the time period August 23 to September 17, after which only Type I clouds formed. During AASE, while Type I clouds were formed for each day between January 3 and February 10, Type II clouds formed on only two days, January 24 and 31. Mie theory and a radiative transfer model are used to compute the radiative heating rates during the mission periods, for clear and cloudy lower sky cases. Only the Type II water ice clouds have a significant radiative effect, with the Type I NATO PSCs generating a net heating or cooling of 0.1 K/d or less.

  15. USCGC Polar Star Arctic West Summer 2002 Cruise Summary: Shelf-Basin Interactions

    E-print Network

    Pickart, Robert S.

    of the 2002 Arctic West Summer cruise (AWS02) were to (1) deploy a system of moorings that will measure 150 150 200 200 200 200 200 500 500 500 500 1000 1000 1000 2000 2000 2000 3000 3000 3000 Alaska AWS02 Shelf-basin Interactions 15 Jul--13 Aug, 2002 1 2 3 4 5 6 Figure 1: AWS02 CTD stations (inverted red

  16. Oceanographic Aspects of Recent Changes in the Arctic

    NASA Astrophysics Data System (ADS)

    Morison, J. H.

    2002-12-01

    In the Arctic recent decadal-scale changes have marked the atmosphere, ocean, and land. Connections between the oceanographic changes and large-scale atmospheric circulation changes are emerging. Surface atmospheric pressure has shown a declining trend over the Arctic. In the 1990s, the Arctic Ocean circulation took on a more cyclonic character, and the front separating Atlantic-derived waters of the Eurasian Basin and the Pacific-derived waters of the Canadian Basin shifted counterclockwise. The temperature of Atlantic water in the Arctic Ocean reached record levels. The cold halocline, which isolates the surface from the warm Atlantic water, grew thinner disappearing entirely from the Amundsen Basin at one point [Steele and Boyd, 1998]. Arctic sea ice extent has decreased 3% per decade since the 1970s [Parkinson et al., 1999]. Sea ice thickness over much of the Arctic decreased 43% between 1958-1976 and 1993-1997 [Rothrock et al., 1999]. Arctic ecosystems have responded to these changes. Sea ice studies in the late 1990s indicate that the sea ice algal species composition changed from decades before, with the species recently being characterized by more brackish and freshwater forms. Barents Sea fisheries have shifted north following reductions in ice extent. Pacific salmon species have been found entering rivers in the Arctic. There is evidence that this complex of pan-Arctic changes is connected with the rising trend in the Arctic Oscillation (AO) or Northern Hemisphere atmospheric polar vortex in the 1990s. Theoretical evidence that a positive trend in the AO index might be indicative of greenhouse warming raises the possibility that the recent complex of changes is an Arctic characteristic of global climate change. Also, the changes in ice cover manifest a connection between the complex of change and global climate through ice-albedo feedback, by which reductions in ice cover reduce the amount of sunlight reflected from the earth's surface. Another important climate feedback is that the changes in ocean circulation and ice production have increased the amount of relatively fresh surface water exported to the sub-Arctic Seas, increasing stratification there, and arguably reducing the strength of the global thermohaline circulation. Since the mid-1990s the strength of the Polar Vortex (AO) has relaxed partially toward earlier levels. Recent observations show that Arctic Ocean water mass structure has relaxed somewhat towards climatology near the surface but is still changing at depth. The cold halocline has recovered in some areas. This reinforces the notion that the changes in the Arctic are tied to the atmospheric circulation of the whole northern hemisphere. The events of the last 10-15 years suggest ways the Arctic environment may be an indicator and agent of climate change and highlight the importance of a systematic program to observe the changing Arctic. References Parkinson C. L., D. J. Cavalieri, P. Gloersen, H. J. Zwally, and J. C. Comiso, 1999, Arctic sea ice extents, areas, and trends, 1978-1996, J. Geophys. Res., 104, 20,387-20,856. Rothrock, D. A., Y. Yu, and G. A. Maykut, 1999, Thinning of the Arctic sea-ice cover, Geophys. Res. Lett., 26(23), 3469-3472. Steele, M., and T. Boyd, 1998, Retreat of the cold halocline layer in the Arctic Ocean, J. Geophys. Res., 103, 10,419-10,435.

  17. Polarization of 'water-skies' above arctic open waters: how polynyas in the ice-cover can be visually detected from a distance.

    PubMed

    Hegedüs, Ramón; Akesson, Susanne; Horváth, Gábor

    2007-01-01

    The foggy sky above a white ice-cover and a dark water surface (permanent polynya or temporary lead) is white and dark gray, phenomena called the 'ice-sky' and the 'water-sky,' respectively. Captains of icebreaker ships used to search for not-directly-visible open waters remotely on the basis of the water sky. Animals depending on open waters in the Arctic region may also detect not-directly-visible waters from a distance by means of the water sky. Since the polarization of ice-skies and water-skies has not, to our knowledge, been studied before, we measured the polarization patterns of water-skies above polynyas in the arctic ice-cover during the Beringia 2005 Swedish polar research expedition to the North Pole region. We show that there are statistically significant differences in the angle of polarization between the water-sky and the ice-sky. This polarization phenomenon could help biological and man-made sensors to detect open waters not directly visible from a distance. However, the threshold of polarization-based detection would be rather low, because the degree of linear polarization of light radiated by water-skies and ice-skies is not higher than 10%. PMID:17164851

  18. Depletion of stratospheric ozone over the Antarctic and Arctic: responses of plants of polar terrestrial ecosystems to enhanced UV-B, an overview.

    PubMed

    Rozema, Jelte; Boelen, Peter; Blokker, Peter

    2005-10-01

    Depletion of stratospheric ozone over the Antarctic has been re-occurring yearly since 1974, leading to enhanced UV-B radiation. Arctic ozone depletion has been observed since 1990. Ozone recovery has been predicted by 2050, but no signs of recovery occur. Here we review responses of polar plants to experimentally varied UV-B through supplementation or exclusion. In supplementation studies comparing ambient and above ambient UV-B, no effect on growth occurred. UV-B-induced DNA damage, as measured in polar bryophytes, is repaired overnight by photoreactivation. With UV exclusion, growth at near ambient may be less than at below ambient UV-B levels, which relates to the UV response curve of polar plants. UV-B screening foils also alter PAR, humidity, and temperature and interactions of UV with environmental factors may occur. Plant phenolics induced by solar UV-B, as in pollen, spores and lignin, may serve as a climate proxy for past UV. Since the Antarctic and Arctic terrestrial ecosystems differ essentially, (e.g. higher species diversity and more trophic interactions in the Arctic), generalization of polar plant responses to UV-B needs caution. PMID:16005756

  19. Multi-Instrument Analysis of a Traveling Convection Vortex Event on July 24, 1996 Coordinated with the Polar UVI

    NASA Technical Reports Server (NTRS)

    Sitar, R. J.; Clauer, C. R.; Baker, J. B.; Ridley, A. J.; Cumnock, J.; Germany, G. A.; Spann, J. F., Jr.; Brittnacher, M. J.; Parks, G. K.

    1998-01-01

    We present the analysis of a coordinated set of observations from the POLAR Ultraviolet Imager (UVI), ground magnetometers, incoherent scatter radar, solar wind monitors, DMSP and GOES satellites, focused on a traveling convection vortex (TCV) event on 24th July 1996. Starting at approximately 10:48 UT, around magnetometers in Greenland and northern Canada observe pulsations consistent with the passing overhead of a series of alternating TCV filed-aligned current pairs. Azimuthal scans by the Sondrestrom incoherent scatter radar located near Kangerlussuaq (formerly Sondrestrom), Greenland, at this time show strong modulation in the strength and direction of ionospheric plasma flow. The magnetometer pulsations grow in magnitude over the next hour, peaking in intensity at 11:39 UT, at which time images form the UVI instrument show a localized intensification of auroral emissions over central and western Greenland. Subsequent images show the intensification grow in strength and propagate westward (tailward) until approximately 11:58 UT at which time the intensification fades. These observations are consistent with the westward passage of two pairs of moderately intense TCVs over central Greenland followed by a third very intense TCV pair. The intensification of auroral emissions at 11:39 UT is associated with the trailing vortex of the third TCV pair, thought to be the result of an upward field aligned current. The modulated flow observed by the radar is the result of the strong electric fields associated with the impulsive TCV related field aligned current systems as they pass through the field of view of the radar. Measurements of the solar wind from the V;IND and IMP-8 spacecraft suggest that a pressure change may be responsible for triggering the first two pairs of TCVS, and that a subsequent sudden change in the orientation of the interplanetary magnetic field may have produced the intensification of the third TCV pair and the associated auroral brightening. Magnetometer data from the GOES satellite located over the eastern United States at geostationary orbit is consistent with a series of field-aligned moving tailward past the satellite. DMSP particle data indicated that the TCVs occur on field lines which map to the boundary plasma sheet (BPS).

  20. Aboveground activity rhythm in Arctic black-capped marmot ( Marmota camtschatica bungei Katschenko 1901) under polar day conditions

    NASA Astrophysics Data System (ADS)

    Semenov, Youri; Ramousse, Raymond; Le Berre, Michel; Vassiliev, Vladimir; Solomonov, Nikita

    2001-04-01

    Daily aboveground activity of wild black-capped marmots of Yakutia ( Marmota camtschatica bungei) was recorded under 'polar day' conditions at 71°56' N and 127°19' E (north of the Polar Circle). From the beginning of May until the end of August, the sun was permanently above or close to the horizon. However under this condition of continuous lighting, the aboveground activity of these arctic hibernating mammals was periodic. Onset and end of activity showed marked changes throughout the seasons. Activity time increased strongly from hibernation emergence until the end of July and then decreased slowly until onset of hibernation. Below daily mean temperatures of 5 °C, activity started when the sun was 35° above the horizon, and ended when it dropped below 28°. When daily mean temperatures were above 5 °C, activity onset was synchronised with a solar altitude around 17-18° and activity ended at 10°. Activity onset was more precise relative to the solar altitude than the end of activity. This may be explained by late feeding bouts, following a midday thermal stress. In absence of rapid natural light-dark (LD) transitions that occur at civil twilight, our results suggest that the activity pattern of black-capped marmots may be synchronised by the light cycle through the solar altitude and ambient temperature.

  1. Airborne lidar measurements of ozone during the 1989 airborne Arctic stratospheric expedition

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Fenn, Marta A.; Kooi, Susan A.

    1991-01-01

    The NASA/NOAA Airborne Arctic Stratospheric Expedition (AASE) was conducted during the winter to study the conditions leading to possible ozone (O3) destruction in the wintertime Arctic stratosphere. As part of this experiment, the NASA-Langley airborne differential absorption lidar (DIAL) system was configured for operation on the NASA-Ames DS-8 aircraft to make measurements of O3 profiles from about 1 km above the aircraft to altitudes of 22 to 26 km. The airborne DIAL system remotely sensed O3 above the DC-8 by transmitting two laser beams at 10 Hz using wavelengths of 301.5 and 311 nm. Large scale distributions of O3 were obtained on 15 long range flights into the polar vortex during the AASE. Selected data samples are presented of O3 observed during these flights, general trends observed in O3 distributions, and correlations between these measurements and meteorological and chemical parameters. The O3 distribution observed on the first flight of the DC-8 into the polar vortex on Jan. 6 reflected the result of diabatic cooling of the air inside the vortex during the winter compared to the warmer air outside the vortex. On a potential temperature surface, the O3 mixing ratio generally increases when going from outside to inside the vortex.

  2. Polar bears exhibit genome-wide signatures of bioenergetic adaptation to life in the Arctic environment

    USGS Publications Warehouse

    Welch, Andreanna J.; Bedoya-Reina, Oscar C.; Carretero-Paulet, Lorenzo; Miller, Webb; Rode, Karyn D.; Lindqvist, Charlotte

    2014-01-01

    Polar bears (Ursus maritimus) face extremely cold temperatures and periods of fasting, which might result in more severe energetic challenges than those experienced by their sister species, the brown bear (U. arctos). We have examined the mitochondrial and nuclear genomes of polar and brown bears to investigate if polar bears demonstrate lineage-specific signals of molecular adaptation in genes associated with cellular respiration/energy production. We observed increased evolutionary rates in the mitochondrial cytochrome c oxidase I gene in polar but not brown bears. An amino acid substitution occurred near the interaction site with a nuclear-encoded subunit of the cytochrome c oxidase complex, and was predicted to lead to a functional change, although the significance of this remains unclear. The nuclear genomes of brown and polar bears demonstrate different adaptations related to cellular respiration. Analyses of the genomes of brown bears exhibited substitutions that may alter the function of proteins that regulate glucose uptake, which could be beneficial when feeding on carbohydrate-dominated diets during hyperphagia, followed by fasting during hibernation. In polar bears, genes demonstrating signatures of functional divergence and those potentially under positive selection were enriched in functions related to production of nitric oxide, which can regulate energy production in several different ways. This suggests that polar bears may be able to fine-tune intracellular levels of nitric oxide as an adaptive response to control trade-offs between energy production in the form of ATP versus generation of heat (thermogenesis).

  3. Polar Bears Exhibit Genome-Wide Signatures of Bioenergetic Adaptation to Life in the Arctic Environment

    PubMed Central

    Welch, Andreanna J.; Carretero-Paulet, Lorenzo; Miller, Webb; Rode, Karyn D.; Lindqvist, Charlotte

    2014-01-01

    Polar bears (Ursus maritimus) face extremely cold temperatures and periods of fasting, which might result in more severe energetic challenges than those experienced by their sister species, the brown bear (U. arctos). We have examined the mitochondrial and nuclear genomes of polar and brown bears to investigate whether polar bears demonstrate lineage-specific signals of molecular adaptation in genes associated with cellular respiration/energy production. We observed increased evolutionary rates in the mitochondrial cytochrome c oxidase I gene in polar but not brown bears. An amino acid substitution occurred near the interaction site with a nuclear-encoded subunit of the cytochrome c oxidase complex and was predicted to lead to a functional change, although the significance of this remains unclear. The nuclear genomes of brown and polar bears demonstrate different adaptations related to cellular respiration. Analyses of the genomes of brown bears exhibited substitutions that may alter the function of proteins that regulate glucose uptake, which could be beneficial when feeding on carbohydrate-dominated diets during hyperphagia, followed by fasting during hibernation. In polar bears, genes demonstrating signatures of functional divergence and those potentially under positive selection were enriched in functions related to production of nitric oxide (NO), which can regulate energy production in several different ways. This suggests that polar bears may be able to fine-tune intracellular levels of NO as an adaptive response to control trade-offs between energy production in the form of adenosine triphosphate versus generation of heat (thermogenesis). PMID:24504087

  4. Polar bears exhibit genome-wide signatures of bioenergetic adaptation to life in the arctic environment.

    PubMed

    Welch, Andreanna J; Bedoya-Reina, Oscar C; Carretero-Paulet, Lorenzo; Miller, Webb; Rode, Karyn D; Lindqvist, Charlotte

    2014-02-01

    Polar bears (Ursus maritimus) face extremely cold temperatures and periods of fasting, which might result in more severe energetic challenges than those experienced by their sister species, the brown bear (U. arctos). We have examined the mitochondrial and nuclear genomes of polar and brown bears to investigate whether polar bears demonstrate lineage-specific signals of molecular adaptation in genes associated with cellular respiration/energy production. We observed increased evolutionary rates in the mitochondrial cytochrome c oxidase I gene in polar but not brown bears. An amino acid substitution occurred near the interaction site with a nuclear-encoded subunit of the cytochrome c oxidase complex and was predicted to lead to a functional change, although the significance of this remains unclear. The nuclear genomes of brown and polar bears demonstrate different adaptations related to cellular respiration. Analyses of the genomes of brown bears exhibited substitutions that may alter the function of proteins that regulate glucose uptake, which could be beneficial when feeding on carbohydrate-dominated diets during hyperphagia, followed by fasting during hibernation. In polar bears, genes demonstrating signatures of functional divergence and those potentially under positive selection were enriched in functions related to production of nitric oxide (NO), which can regulate energy production in several different ways. This suggests that polar bears may be able to fine-tune intracellular levels of NO as an adaptive response to control trade-offs between energy production in the form of adenosine triphosphate versus generation of heat (thermogenesis). PMID:24504087

  5. Gaia Paradigm: A Biotic Origin Of The Polar Sunrise Arctic Bromine Explosion

    E-print Network

    M. Iudin

    2010-07-09

    The main attention is given to discussion of the natural causes and regularities of the Arctic bromine pollution. We make notice of marine microbial organisms and their metabolism as a prime driving force for the elemental biogeochemical cycles. One of the important conclusions of this study is on similarity between ocean bromine concentrating as by-product of the marine microbial activities and nitrogen fixation by soil bacteria. In both cases, microbial organisms and their food webs maintain the sustainability of the superficial environments throughout the geological ages of the biotic Earth. Phenomenology of bromine explosion points on synchronization of the biogeochemical processing upon the solar factor. Spatial-temporal extent and statistical properties of the Arctic BrO cloud make the bromine explosion phenomena an exceptionally valuable for modeling. In our analysis of of the interannual (Solar Cycle 23) variability of the BrO cloud, we rely on on the processed from GOME satellite data and on the ground observations. Sustainability of the earth superficial environments is impossible without ozone-oxygen transformations. Bromine pollution activate catalytic depletion of ozone, which leads to the intensification of oxygen fluxes and atmosphere-ocean exchange and to the stimulation of the seasonal production of the superficial Northern Hemisphere's biota. The biotic bromine explosion illustrates the major concepts of Gaia hypothesis and yields on the foundational principle of multiple unity of the Earth's life and planetary operations.

  6. Investigation of polar mesocyclones in Arctic Ocean using COSMO-CLM and WRF numerical models and remote sensing data

    NASA Astrophysics Data System (ADS)

    Varentsov, Mikhail; Verezemskaya, Polina; Baranyuk, Anastasia; Zabolotskikh, Elizaveta; Repina, Irina

    2015-04-01

    Polar lows (PL), high latitude marine mesoscale cyclones, are an enigmatic atmospheric phenomenon, which could result in windstorm damage of shipping and infrastructure in high latitudes. Because of their small spatial scales, short life times and their tendency to develop in remote data sparse regions (Zahn, Strorch, 2008), our knowledge of their behavior and climatology lags behind that of synoptic-scale cyclones. In case of continuing global warming (IPCC, 2013) and prospects of the intensification of economic activity and marine traffic in Arctic region, the problem of relevant simulation of this phenomenon by numerical models of the atmosphere, which could be used for weather and climate prediction, is especially important. The focus of this paper is researching the ability to simulate polar lows by two modern nonhydrostatic mesoscale numerical models, driven by realistic lateral boundary conditions from ERA-Interim reanalysis: regional climate model COSMO-CLM (Böhm et. al., 2009) and weather prediction and research model (WRF). Fields of wind, pressure and cloudiness, simulated by models, were compared with remote sensing data and ground meteorological observations for several cases, when polar lows were observed, in Norwegian, Kara and Laptev seas. Several types of satellite data were used: atmospheric water vapor, cloud liquid water content and surface wind fields were resampled by examining AMSR-E and AMSR-2 microwave radiometer data (MODIS Aqua, GCOM-W1), and wind fields were additionally extracted from QuickSCAT scatterometer. Infrared and visible pictures of cloud cover were obtained from MODIS (Aqua). Completed comparison shown that COSMO-CLM and WRF models could successfully reproduce evolution of polar lows and their most important characteristics such as size and wind speed in short experiments with WRF model and longer (up to half-year) experiments with COSMO-CLM model. Improvement of the quality of polar lows reproduction by these models in relation to source reanalysis fields were investigated. References: 1. Böhm U. et al. CLM - the climate version of LM: Brief description and long-term applications [Journal] // COSMO Newsletter. - 2006. - Vol. 6. 2. IPCC Fifth Assessment Report: Climate Change 2013 (AR5) Rep.,Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. 3. Zahn, M., and H. von Storch (2008), A long-term climatology of North Atlantic polar lows, Geophys. Res. Lett., 35, L22702

  7. Record Arctic Ozone Loss in Spring 2011 compared with Antarctic Ozone Hole Conditions

    NASA Astrophysics Data System (ADS)

    Rex, M.; Wohltmann, I.; Deckelmann, H.; von der Gathen, P.; Manney, G. L.; Santee, M. L.; Livesey, N. J.; Davies, J.; Dorokhov, V.; Gernandt, H.; Johnson, B. J.; Kivi, R.; Kyro, E.; Larsen, N.; Makshtas, A.; McElroy, T.; Nakajima, H.; Parrondo, M.; Tarasick, D. W.; Walker, K. A.; Zinoviev, N. S.

    2011-12-01

    The Arctic winter 2010/2011 was characterized by an unusually stable and cold polar vortex in the lower stratosphere. Meteorological data shows that conditions for the formation of polar stratospheric clouds, and hence the activation of chlorine from reservoir species through heterogeneous processes, were widespread. Values of Vpsc, a temperature based parameter that characterizes the winter average extent of such conditions were in the range of the extreme values reached in the coldest winters on record, i.e., 2000 and 2005. However, in contrast to these previous winters, when the ozone loss period was ended by major stratospheric warmings in March, in 2011 the very stable polar vortex stayed intact and cold well into April. The combination of extremely cold conditions throughout the winter with a long lived and stable vortex in spring led to record chemical destruction of ozone in the Arctic. Based on the measurements of the Match ozonesonde network and the Microwave Limb Sounder (MLS) instrument on Aura we will discuss the degree and the time evolution of this record loss and compare the Arctic ozone loss in 2011 with the range of ozone losses that occurred in early and recent Antarctic ozone holes.

  8. Such Low Temperatures in the Arctic Region: How Can the Polar Bears Call It Home?

    ERIC Educational Resources Information Center

    Pringle, Rose M.

    2002-01-01

    Presents an activity on polar bears that integrates language arts and science. Teaches the characteristics of organisms and how distinct environments support distinct organisms. Uses both mathematics and science skills and targets students at the K-4 grade level. (YDS)

  9. POLAR-PALOOZA Polar Researchers and Arctic Residents Engage, Inform and Inspire Diverse Public Audiences by sharing Polar Science and Global Connections during the International Polar Year, using a New Model of Informal Science Education

    NASA Astrophysics Data System (ADS)

    Haines-Stiles, G.; Akuginow, E.

    2006-12-01

    (Please note that the POLAR-PALOOZA initiative described in this Abstract is-as of 9/7/2006-"pending" for possible support from NSF and NASA as part of this year's IPY solicitation. Subject to decisions expected by 9/30, this presentation would either be withdrawn, or amplified with specific participants, locations and dates.) Despite the success of well-regarded movies like "March of the Penguins", the polar regions remain a great unknown for most people. Public knowledge about the Arctic and Antarctic, and the critical role of the Poles in the entire Earth system, is nonexistent, incomplete or burdened with misperceptions. The International Polar Years of 2007-2009-and associated "I*Y" science years such as IHY, IYPE and eGY-present a unique opportunity to change this. The people who can best effect this change are those who know the Poles best, through living or working there. Based on innovative but proven models, POLAR-PALOOZA will use three complementary strategies to engage, inform and inspire large public audiences. (1) A national tour, under the working title "Stories from a Changing Planet", will include in-person presentations at science centers, museums, libraries and schools across North America, including Canada and Mexico. The presentations will be augmented by High Definition Video taped on location at the Poles, audio and video podcasts, and special education and outreach activities for targeted audiences. "Stories from a Changing Planet" will provide diverse audiences with an exciting opportunity to meet and interact directly with polar experts, and to appreciate why the Poles and the research done there are directly relevant to their lives. (2) The "HiDef Video Science Story Capture Corps" is a team of professional videographers, using the latest generation of low-cost, high-quality cameras, deployed to both Poles. They will document the work of multiple researchers and projects, rather than focusing on one topic for a single broadcast program. The resulting HD footage will be cataloged, archived and made available as public domain material, accessible to government research agencies for media releases, to the researchers and their home universities, and to science centers and museums. (3) POLAR- PALOOZA will edit short video and audio podcasts from this archive, and distribute them non-exclusively through an open network of websites, including iTunes, YouTube, Google, Yahoo, and the official IPY, US-IPY, NSF and NASA websites. Project design targets underserved groups and regions, and has developed a detailed strategy by which to reach out to under-served minorities and mid-sized and smaller communities over the entire two years of IPY. A balanced cadre of researchers, both male and female, young and old, ethnically-diverse and representing the many disciplines engaged in polar research, has already been identified, and over twenty five scientists, engineers, artists and journalists have committed to participating. The project's Advisors include members of the National Academy's Polar Research Board, and the two U.S. representatives to the international IPY Education and Outreach Committee.

  10. In-Situ Measurements of BrO in the early 2011/2012 Arctic Polar Vortex

    NASA Astrophysics Data System (ADS)

    Heinecke, F.; Afchine, A.; von Hobe, M.; Richter, A.; Schönfeld, A.; Steinert, C.; Suminska, O.; Tan, V.; Stroh, F.

    2012-04-01

    The Bromine Monoxide radical was measured along with Chlorine Monoxide with the HALOX instrument during two flights of the M55-Geophysica high-altitude research aircraft from Kiruna (Sweden) employing the Chemical Conversion Resonance Fluorescence (CCRF) Technique, first demonstrated on aircraft by Brune et al., 1989. In the effort to narrow down the remaining uncertainties for the inorganic Bromine loading (Bry) of the stratosphere, In-Situ BrO data provide valuable information, as BrO is the most abundant inorganic Bromine species in sunlit stratospheric air. The BrO detection limit was lowered by recent modifications of the optical setup in the HALOX instrument aiming at the reduction of stray light. However a closer look at the stray light problem also revealed the need for an improved instrument calibration. A concept for a reliable calibration was developed. The new method will be applied to the new dataset and compared to the former calibration. The results from the acquired BrO data along the flight track will be discussed and compared to earlier measurements. Based on the demonstrated field performance the potential of the CCRF technique to quantify the extremely low BrO concentrations in the UTLS and TTL regions in future tropical field measurements will be evaluated. Brune, W. H., J. G. Anderson, and K. R. Chan (1989), In Situ Observations of BrO Over Antarctica: ER-2 Aircraft Results From 54°S to 72°S Latitude, J. Geophys. Res., 94(D14), 16,639-16,647, doi:10.1029/JD094iD14p16639.

  11. feeding rhythm during the Arctic polar day and night [14], and the emperor

    E-print Network

    Ghazanfar, Asif

    . Importantly, circadian arrhythmia in reindeer does not mean complete arrhythmia. Indeed, as Lu et al. [1.J., Gerkema, M.P., Folkow, L., Blix, A.S., and Stokkan, K.A. (2005). Circadian organization in reindeer). Where clocks are redundant: weak circadian mechanisms in reindeer living under polar photic conditions

  12. Interhemispheric differences in polar stratospheric HNO3, H2O, ClO, and O3

    NASA Technical Reports Server (NTRS)

    Santee, M. L.; Read, W. G.; Waters, J. W.; Froidevaux, L.; Manney, G. L.; Flower, D. A.; Jarnot, R. F.; Harwood, R. S.; Peckham, G. E.

    1995-01-01

    Simultaneous global measurements of nitric acid (HNO3), water (H2O), chlorine monoxide (ClO), and ozone (O3) in the stratosphere have been obtained over complete annual cycles in both hemispheres by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite. A sizeable decrease in gas-phase HNO3 was evident in the lower stratospheric vortex over Antarctica by early June 1992, followed by a significant reduction in gas-phase H2O after mid-July. By mid-August, near the time of peak ClO, abundances of gas-phase HNO3 and H2O were extremely low. The concentrations of HNO3 and H2O over Antarctica remained depressed into November, well after temperatures in the lower stratosphere had risen above the evaporation threshold for polar stratospheric clouds, implying that denitrification and dehydration had occurred. No large decreases in either gas-phase HNO3 or H2O were observed in the 1992-1993 Arctic winter vortex. Although ClO was enhanced over the Arctic as it was over the Antarctic, Arctic O3 depletion was substantially smaller than that over Antarctica. A major factor currently limiting the formation of an Arctic ozone 'hole' is the lack of denitrification in the northern polar vortex, but future cooling of the lower stratosphere could lead to more intense denitrification and consequently larger losses of Arctic ozone.

  13. Interhemispheric differences in polar stratospheric HNO3, H2O, ClO, and O3

    SciTech Connect

    Santee, M.L.; Read, W.G.; Waters, J.W.; Froidevaux, L.; Manney, G.L.; Flower, D.A.; Jarnot, R.F.; Harwood, R.S.; Peckham, G.E.

    1995-02-01

    Simultaneous global measurements of nitric acid (HNO3), water (H2O), chlorine monoxide (ClO), and ozone (O3) in the stratosphere have been obtained over complete annual cycles in both hemispheres by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite. A sizeable decrease in gas-phase HNO3 was evident in the lower stratospheric vortex over Antarctica by early June 1992, followed by a significant reduction in gas-phase H2O after mid-July. By mid-August, near the time of peak ClO, abundances of gas-phase HNO3 and H2O were extremely low. The concentrations of HNO3 and H2O over Antarctica remained depressed into November, well after temperatures in the lower stratosphere had risen above the evaporation threshold for polar stratospheric clouds, implying that denitrification and dehydration had occurred. No large decreases in either gas-phase HNO3 or H2O were observed in the 1992-1993 Arctic winter vortex. Although ClO was enhanced over the Arctic as it was over the Antarctic, Arctic O3 depletion was substantially smaller than that over Antarctica. A major factor currently limiting the formation of an Arctic ozone `hole` is the lack of denitrification in the northern polar vortex, but future cooling of the lower stratosphere could lead to more intense denitrification and consequently larger losses of Arctic ozone.

  14. Arctic stratospheric dehydration - Part 1: Unprecedented observation of vertical redistribution of water

    NASA Astrophysics Data System (ADS)

    Khaykin, S. M.; Engel, I.; Vömel, H.; Formanyuk, I. M.; Kivi, R.; Korshunov, L. I.; Krämer, M.; Lykov, A. D.; Meier, S.; Naebert, T.; Pitts, M. C.; Santee, M. L.; Spelten, N.; Wienhold, F. G.; Yushkov, V. A.; Peter, T.

    2013-05-01

    We present high-resolution measurements of water vapour, aerosols and clouds in the Arctic stratosphere in January and February 2010 carried out by in-situ instrumentation on balloon-sondes and high-altitude aircraft combined with satellite observations. The measurements provide unparalleled evidence of dehydration and rehydration due to gravitational settling of ice particles. An extreme cooling of the Arctic stratospheric vortex during the second half of January 2010 resulted in a rare synoptic-scale outbreak of ice PSCs (polar stratospheric clouds) detected remotely by the lidar aboard the CALIPSO satellite. The widespread occurrence of ice clouds was followed by sedimentation and consequent sublimation of ice particles, leading to vertical redistribution of water inside the vortex. A sequence of balloon and aircraft soundings with chilled mirror and Lyman-? hygrometers (CFH, FISH, FLASH) and backscatter sondes (COBALD) conducted in January 2010 within the LAPBIAT and RECONCILE campaigns captured various phases of this phenomenon: ice formation, irreversible dehydration and rehydration. Consistent observations of water vapour by these independent measurement techniques show clear signatures of irreversible dehydration of the vortex air by up to 1.6 ppmv in the 20-24 km altitude range and rehydration by up to 0.9 ppmv in a 1 km-thick layer below. Comparison with space-borne Aura MLS water vapour observations allow the spatiotemporal evolution of dehydrated air masses within the Arctic vortex to be derived and upscaled.

  15. Investigation of Polar Stratospheric Cloud Solid Particle Formation Mechanisms Using ILAS and AVHRR Observations in the Arctic

    NASA Technical Reports Server (NTRS)

    Irie, H.; Pagan, K. L.; Tabazadeh, A.; Legg, M. J.; Sugita, T.

    2004-01-01

    Satellite observations of denitrification and ice clouds in the Arctic lower stratosphere in February 1997 are used with Lagrangian microphysical box model calculations to evaluate nucleation mechanisms of solid polar stratospheric cloud (PSC) particles. The occurrences of ice clouds are not correlated in time and space with the locations of back trajectories of denitrified air masses, indicating that ice particle surfaces are not always a prerequisite for the formation of solid PSCs that lead to denitrification. In contrast, the model calculations incorporating a pseudoheterogeneous freezing process occurring at the vapor-liquid interface can quantitatively explain most of the observed denitrification when the nucleation activation free energy for nitric acid dihydrate formation is raised by only approx.10% relative to the current published values. Once nucleated, the conversion of nitric acid dihydrate to the stable trihydrate phase brings the computed levels of denitrification closer to the measurements. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0320 Atmospheric Composition and SblctureC: loud physics and chemistry; 0340 Atmospheric Composition and Structure: Middle atmosphere-composition and chemistry

  16. Understanding the Arctic stratosphere during IPY through a combination of ground-based measurements, models and dynamical analyses

    NASA Astrophysics Data System (ADS)

    Batchelor, R.; Strong, K.; Lindenmaier, R.; Manson, A.; Meek, C.; Manney, G.; Daffer, W.; Polavarapu, S.; Reszka, M.; Neish, M.; Robichaud, A.; Degrandpré, J.; Roch, M.; Chabrillat, S.; Beagley, S.; Barthlott, S.; Blumenstock, T.; Hase, F.; Klyft, J.; Strandberg, A.; Mellqvist, J.; Palm, M.; Notholt, J.; Hannigan, J.; Coffey, M.; Kasai, Y.; Kagawa, A.

    2009-05-01

    While chemical ozone depletion in the Antarctic spring-time stratosphere is now an annually occurring and well-understood phenomenon, dynamical variability in the Arctic stratosphere means ozone depletion in the northern polar vortex is both less predictable and more susceptible to changes resulting from climate change than in the southern vortex. In order to examine ozone-depleting processes and quantify chemical changes occurring in the Arctic polar stratosphere, it is important to combine a range of data sources to describe both the chemistry and the dynamics of the polar vortex. Ground-based Fourier transform spectroscopy provides a well-defined and useful data set of atmospheric trace gas measurements around the globe. Key chemical species involved in stratospheric ozone depletion, including chlorine reservoirs HCl and ClONO2, nitrogen reservoir HNO3, fluorine reservoir HF and ozone itself are standard measurements for the Network for the Detection of Atmospheric Composition Change (NDACC) Fourier transform infrared (FTIR) spectrometers. During the 2007 and 2008 International Polar Year (IPY) spring periods, measurements were made with ground-based FTIR spectrometers at six NDACC stations around the Arctic. In this work, these measurements will be used in conjunction with dynamical analyses in order to characterize the Arctic polar stratosphere. In addition, the measurements will be compared and contrasted with the IPY runs of two meteorologically assimilated global chemistry models, the Canadian Middle Atmosphere Model - Data Assimilated (CMAM-DA), and the Environment Canada Global Environmental Multiscale stratospheric model, run with the BIRA (Belgian Institute for Space Aeronomy) online chemistry package (GEM-BACH) in order to better quantify our current understanding of the processes occurring in the polar atmosphere.

  17. Evaluation of the SKYHI general circulation model using aircraft N2O measurements. 1: Polar winter stratospheric meteorology and tracer morphology

    SciTech Connect

    Strahan, S.E.; Mahlman, J.D. NOAA Geophysical Fluid Dynamics Lab, Princeton, NJ )

    1994-05-01

    Winter polar stratospheric nitric oxide (N2O) measurements made during two NASA polar aircraft field campaigns are used to evaluate the dynamics of the Geophysical Fluid Dynamics Laboratory's 'SKYHI' general circulation model. SKYHI has 1 deg latitude by 1.2 deg longitude grid spacing and 40 vertical levels (up to 80 km) and precscribed N2O dissociation coefficients. The model has been integrated a total of 20 months, producing one Antarctic and two Artic winters. The climatologies of these winters are compared with the known northern and southern hemisphere climatologies and to the meteorological conditions durng the time of the field campaigns. The two Arctic SKYHI winters show considerable interannual variability. In the lower stratosphere, SKYHI realistically simulates the magnitude and variability of winds and temperatures both inside and outside the polar vortex and can produce a credible sudden warming. In the Antarctic the magnitude and variablity of winds and temperatures around the polar vortex are quite realistic, but inside the vortex, temperatures are too low. Flight data from each mission have been averaged together to produce a contour map showing N2O morphology in and around the vortex. Because the N2O distribution in the lower stratosphere is under dynamical control, the mean N2O field can be used to interpret the dynamics of the polar stratosphere. At the Arctic vortex edge, Airborne Arctic Stratospheric Experiment (AASE) data show large gradients of N2O on isentropic surfaces. SKYHI vortex edge gradients are nearly as large, and model mixing ratios between 400 and 500 K (potential temperature) are similar to the observations. In the Antarctic, model mixing ratios are too high everywhere and the edge gradients are flatter than the observed gradients. The comparison of mean N2O fields suggests realistic wave activity in the SKYHI Arctic winter but inadequate wave activity in the SKYHI Antarctic winter.

  18. Polar night retrievals of trace gases in the Arctic using the Extended-range Atmospheric Emitted Radiance Interferometer

    NASA Astrophysics Data System (ADS)

    Mariani, Z.; Strong, K.; Palm, M.; Lindenmaier, R.; Adams, C.; Zhao, X.; Savastiouk, V.; McElroy, C. T.; Goutail, F.; Drummond, J. R.

    2013-01-01

    The Extended-range Atmospheric Emitted Radiance Interferometer (E-AERI) was installed at the Polar Environment Atmospheric Research Laboratory (PEARL) at Eureka, Nunavut, Canada in October 2008. Spectra from the E-AERI provide information about the radiative balance and budgets of trace gases in the Canadian high Arctic. Measurements are taken every seven minutes year-round, including polar night when the solar-viewing spectrometers at PEARL are not operated. This allows E-AERI measurements to fill the gap in the PEARL dataset during the four months of polar night. Measurements were taken year-round in 2008-2009 at the PEARL Ridge Lab, which is 610 m above sea-level, and from 2011-onwards at the Zero-Altitude PEARL Auxiliary Lab (0PAL), which is 15 km from the Ridge Lab at sea level. Total columns of O3, CO, CH4, and N2O have been retrieved using a modified version of the SFIT2 retrieval algorithm adapted for emission spectra. This provides the first nighttime measurements of these species at Eureka. Changes in the total columns driven by photochemistry and dynamics are observed. Analyses of E-AERI retrievals indicate accurate spectral fits (root-mean-square residuals < 1.5%) and a 10-15% uncertainty in the total column, depending on the trace gas. O3 comparisons between the E-AERI and a Bruker IFS 125HR Fourier transform infrared (FTIR) spectrometer, three Brewer spectrophotometers, two UV-visible ground-based spectrometers, and a System D'Analyse par Observations Zenithales (SAOZ) at PEARL are made from 2008-2009 and for 2011. 125HR CO, CH4, and N2O columns are also compared with the E-AERI measurements. Mean relative differences between the E-AERI and the other spectrometers are 1-14% (depending on the gas), which are less than the E-AERI's total column uncertainties. The E-AERI O3 and CO measurements are well correlated with the other spectrometers; the best correlation is with the 125HR (r > 0.92). The 24-h diurnal cycle and 365-day seasonal cycle of CO are observed and their amplitudes are quantified by the E-AERI (6-12% and 46%, respectively). The seasonal variability of H2O has an impact on the retrievals, leading to larger uncertainties in the summer months. Despite increased water vapour at the lower-altitude site 0PAL, measurements at 0PAL are consistent with measurements at PEARL.

  19. Deep lakes in the Polar Urals - unique archives for reconstructing the Quaternary climate and glacial history in the Russian Arctic

    NASA Astrophysics Data System (ADS)

    Svendsen, J.; Gyllencreutz, R.; Henriksen, M.; Lohne, O. S.; Mangerud, J.; Nazarov, D.

    2009-12-01

    A lake coring campaign in the Polar Urals is carried out within the framework of the Norwegian-Russian IPY-project “The Ice Age Development and Human Settlement in Northern Eurasia” (ICEHUS). The overall aim of the project is to improve the description and understanding of the Late Quaternary environmental and climate changes in the Russian Arctic and how these changes may have affected the early human occupation. In order to obtain a continuous record of climate variability back in time seismic records and sediment cores have been collected from selected mountain lakes. The summer of 2009 we cored two lakes situated near the water shed in the interior northernmost Urals. Seismic profiles show that both these glacially eroded basins contain thick sequences of Quaternary sediments. The thickest strata were found in Bolshoye Shuchye, the largest and deepest lake in the Ural Mountains. This lake is 13 km long and 140 m deep and contains more than 130 m of acoustically laminated sediments. These strata probably accumulated over a rather long time span, possibly covering several interglacial-glacial cycles. Up to 24 m long cores were obtained from the lake floors. We anticipate that they will provide unique high resolution records of the climate and glacial history during the last Ice Age. The seismic records and the sediment cores will form a well-founded basis for assessing the potential and possibilities to core also the deeper strata that could not be reached with the applied coring equipment. In view of the obtained results from the investigated basins, as well as other geological and geochronological data from the surrounding areas, we find it highly unlikely that any glaciers extended into these lakes during the Last Glacial Maximum (LGM), supporting our current hypothesis that the local glaciers in the Polar Urals remained small during the LGM. Our observations indicate that the mountain valleys have been essentially ice free since Marine Isotope Stage 4, at around 70-60,000 yrs ago. At this time, the major valley systems in the Polar Urals seem to have been inundated by an ice sheet advance from the Kara Sea. Fresh results from the coring campaign will be presented during the meeting.

  20. Comparative hepatic in vitro depletion and metabolite formation of major perfluorooctane sulfonate precursors in Arctic polar bear, beluga whale, and ringed seal.

    PubMed

    Letcher, Robert J; Chu, Shaogang; McKinney, Melissa A; Tomy, Gregg T; Sonne, Christian; Dietz, Rune

    2014-10-01

    Perfluorooctane sulfonate (PFOS) has been reported to be among the most concentrated persistent organic pollutants in Arctic marine wildlife. The present study examined the in vitro depletion of major PFOS precursors, N-ethyl-perfluorooctane sulfonamide (N-EtFOSA) and perfluorooctane sulfonamide (FOSA), as well as metabolite formation using an assay based on enzymatically viable liver microsomes for three top Arctic marine mammalian predators, polar bear (Ursus maritimus), beluga whale (Delphinapterus leucas), and ringed seal (Pusa hispida), and in laboratory rat (Rattus rattus) serving as a general mammalian model and positive control. Rat assays showed that N-EtFOSA (38 nM or 150 ng mL(-1)) to FOSA metabolism was >90% complete after 10 min, and at a rate of 23 pmol min(-1) mg(-1) protein. Examining all species in a full 90 min incubation assay, there was >95% N-EtFOSA depletion for the rat active control and polar bear microsomes, ?65% for ringed seals, and negligible depletion of N-EtFOSA for beluga whale. Concomitantly, the corresponding in vitro formation of FOSA from N-EtFOSA was also quantitatively rat?polar bear>ringed seal>beluga whale. A lack of enzymatic ability and/or a rate too slow to be detected likely explains the lack of N-EtFOSA to FOSA transformation for beluga whale. In the same assays, the depletion of the FOSA metabolite was insignificant (p>0.01) and with no concomitant formation of PFOS metabolite. This suggests that, in part, a source of FOSA is the biotransformation of accumulated N-EtFOSA in free-ranging Arctic ringed seal and polar bear. PMID:25048910

  1. 1Frey & Smith 2003: Polar Research 22(2), xx-xx The sensitivity of Arctic climate is documented

    E-print Network

    in West Siberia and their association with the Arctic Oscillation Karen E. Frey & Laurence C. Smith located throughout West Siberia are used to identify climatic trends and determine to what extent in atmospheric variability are associated with broad Arctic climate change, West Siberia appears particularly

  2. A Composite View of Ozone Evolution in the 1995-1996 Northern Winter Polar Vortex Developed from Airborne Lidar and Satellite Observations

    NASA Technical Reports Server (NTRS)

    Douglass, A. R.; Schoeberl, M. R.; Kawa, S. R.; Browell, E. V.

    2000-01-01

    The processes which contribute to the ozone evolution in the high latitude northern lower stratosphere are evaluated using a three dimensional model simulation and ozone observations. The model uses winds and temperatures from the Goddard Earth Observing System Data Assimilation System. The simulation results are compared with ozone observations from three platforms: the differential absorption lidar (DIAL) which was flown on the NASA DC-8 as part of the Vortex Ozone Transport Experiment; the Microwave Limb Sounder (MLS); the Polar Ozone and Aerosol Measurement (POAM II) solar occultation instrument. Time series for the different data sets are consistent with each other, and diverge from model time series during December and January. The model ozone in December and January is shown to be much less sensitive to the model photochemistry than to the model vertical transport, which depends on the model vertical motion as well as the model vertical gradient. We evaluate the dependence of model ozone evolution on the model ozone gradient by comparing simulations with different initial conditions for ozone. The modeled ozone throughout December and January most closely resembles observed ozone when the vertical profiles between 12 and 20 km within the polar vortex closely match December DIAL observations. We make a quantitative estimate of the uncertainty in the vertical advection using diabatic trajectory calculations. The net transport uncertainty is significant, and should be accounted for when comparing observations with model ozone. The observed and modeled ozone time series during December and January are consistent when these transport uncertainties are taken into account.

  3. What Controls the Temperature of the Arctic Stratosphere during the Spring?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Rosenfield, Joan E.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Understanding the mechanisms that control the temperature of the polar lower stratosphere during spring is key to understanding ozone loss in the Arctic polar vortex. Spring ozone loss rates are directly tied to polar stratospheric temperatures by the formation of polar stratospheric clouds, and the conversion of chlorine species to reactive forms on these cloud particle surfaces. In this paper, we study those factors that control temperatures in the polar lower stratosphere. We use the National Centers for Environmental Prediction (NCEP)/NCAR reanalysis data covering the last two decades to investigate how planetary wave driving of the stratosphere is connected to polar temperatures. In particular, we show that planetary waves forced in the troposphere in mid- to late winter (January-February) are principally responsible for the mean polar temperature during the March period. These planetary waves are forced by both thermal and orographic processes in the troposphere, and propagate into the stratosphere in the mid and high latitudes. Strong mid-winter planetary wave forcing leads to a warmer Arctic lower stratosphere in early spring, while weak mid-winter forcing leads to cooler Arctic temperatures.

  4. Global Hawk dropsonde observations of the Arctic atmosphere obtained during the Winter Storms and Pacific Atmospheric Rivers (WISPAR) field campaign

    NASA Astrophysics Data System (ADS)

    Intrieri, J. M.; de Boer, G.; Shupe, M. D.; Spackman, J. R.; Wang, J.; Neiman, P. J.; Wick, G. A.; Hock, T. F.; Hood, R. E.

    2014-11-01

    In February and March of 2011, the Global Hawk unmanned aircraft system (UAS) was deployed over the Pacific Ocean and the Arctic during the Winter Storms and Pacific Atmospheric Rivers (WISPAR) field campaign. The WISPAR science missions were designed to (1) mprove our understanding of Pacific weather systems and the polar atmosphere; (2) evaluate operational use of unmanned aircraft for investigating these atmospheric events; and (3) demonstrate operational and research applications of a UAS dropsonde system at high latitudes. Dropsondes deployed from the Global Hawk successfully obtained high-resolution profiles of temperature, pressure, humidity, and wind information between the stratosphere and surface. The 35 m wingspan Global Hawk, which can soar for ~ 31 h at altitudes up to ~ 20 km, was remotely operated from NASA's Dryden Flight Research Center at Edwards Air Force Base (AFB) in California. During the 25 h polar flight on 9-10 March 2011, the Global Hawk released 35 sondes between the North Slope of Alaska and 85° N latitude, marking the first UAS Arctic dropsonde mission of its kind. The polar flight transected an unusually cold polar vortex, notable for an associated record-level Arctic ozone loss, and documented polar boundary layer variations over a sizable ocean-ice lead feature. Comparison of dropsonde observations with atmospheric reanalyses reveal that, for this day, large-scale structures such as the polar vortex and air masses are captured by the reanalyses, while smaller-scale features, including low-level jets and inversion depths, are mischaracterized. The successful Arctic dropsonde deployment demonstrates the capability of the Global Hawk to conduct operations in harsh, remote regions. The limited comparison with other measurements and reanalyses highlights the potential value of Arctic atmospheric dropsonde observations where routine in situ measurements are practically nonexistent.

  5. Arctic greening can cause earlier seasonality of Arctic amplification

    E-print Network

    Frierson, Dargan

    [Intergovernmental Panel on Climate Change AR4, 2007]. This feature, referred to as Arctic amplification to the annual mean. Although vegetation changes throughout the year, its effect on Arctic climate may exhibit, Pasadena, California, USA, 3 Division of Polar Climate Change Research, Korea Polar Research Institute

  6. Longer ice-free seasons increase the risk of nest depredation by polar bears for colonial breeding birds in the Canadian Arctic.

    PubMed

    Iverson, Samuel A; Gilchrist, H Grant; Smith, Paul A; Gaston, Anthony J; Forbes, Mark R

    2014-03-22

    Northern polar regions have warmed more than other parts of the globe potentially amplifying the effects of climate change on biological communities. Ice-free seasons are becoming longer in many areas, which has reduced the time available to polar bears (Ursus maritimus) to hunt for seals and hampered bears' ability to meet their energetic demands. In this study, we examined polar bears' use of an ancillary prey resource, eggs of colonial nesting birds, in relation to diminishing sea ice coverage in a low latitude region of the Canadian Arctic. Long-term monitoring reveals that bear incursions onto common eider (Somateria mollissima) and thick-billed murre (Uria lomvia) nesting colonies have increased greater than sevenfold since the 1980s and that there is an inverse correlation between ice season length and bear presence. In surveys encompassing more than 1000 km of coastline during years of record low ice coverage (2010-2012), we encountered bears or bear sign on 34% of eider colonies and estimated greater egg loss as a consequence of depredation by bears than by more customary nest predators, such as foxes and gulls. Our findings demonstrate how changes in abiotic conditions caused by climate change have altered predator-prey dynamics and are leading to cascading ecological impacts in Arctic ecosystems. PMID:24500172

  7. Unraveling the empirical relationship between Arctic stratospheric ozone loss and temperature

    NASA Astrophysics Data System (ADS)

    von Hobe, Marc; Grooß, Jens-Uwe; Müller, Rolf

    2014-05-01

    Ever since the discovery of the Antarctic ozone hole it has been recognized that cold temperatures play a key role in fostering strong ozone depletion in the polar stratosphere. Compact negative correlations between total winter ozone loss and vortex area exposed to temperatures below certain threshold values have been demonstrated (e.g. Harris et al., 2010; Rex et al., 2006; Rex et al., 2004). The most commonly used threshold is the NAT equilibrium temperature, but other choices have been suggested, such as the temperature when the rate of chlorine activation on liquid aerosols exceeds a certain limit. Interestingly, both thresholds relate to critical temperatures in the context of heterogeneous chlorine activation, and Harris et al., 2010, stated that original activation (i.e. the activation in early winter) is the most important factor influencing ozone loss. But at least two other key processes - catalytic ozone loss and denitrification - depend directly on temperature, and temperature also controls the stability and therefore the persistence of the polar vortex. Here, we investigate such "vortex area" correlations for a number of different temperature thresholds, as well as direct correlations with vortex mean temperature and with the date of the final warming. We also carry out sensitivity studies using the Chemical Lagrangian Model of the Stratosphere (CLaMS) to investigate the response of ozone loss to temperature modifications for particle formation and growth, surface reaction probabilities and gas phase reactivity separately. Rex et al., Arctic ozone loss and climate change, Geophys. Res. Lett., 31, L04116, 2004. Rex et al., Arctic winter 2005: Implications for stratospheric ozone loss and climate change, Geophys. Res. Lett., 33, L23808, 2006. Harris et al., A closer look at Arctic ozone loss and polar stratospheric clouds, Atmos. Chem. Phys., 10, 8499-8510, 2010.

  8. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing

    E-print Network

    Marshall, John C.

    In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries ...

  9. A CCM simulation of the breakup of the Antarctic polar vortex in the years 1980-2004 under the CCMVal scenarios

    NASA Astrophysics Data System (ADS)

    Akiyoshi, H.; Zhou, L. B.; Yamashita, Y.; Sakamoto, K.; Yoshiki, M.; Nagashima, T.; Takahashi, M.; Kurokawa, J.; Takigawa, M.; Imamura, T.

    2009-02-01

    The changes in breakup time of the Antarctic polar vortex in the years 1980-2004 are examined using the output of chemistry climate model (CCM) calculations, data from the National Centers for Environmental Prediction/the National Center for Atmospheric Research (NCEP/NCAR) Reanalysis, and data from the European Center for Medium-Range Weather Forecasts Reanalysis (ERA40). The CCM used in this study is from the Center for Climate System Research/National Institute for Environmental Studies (CCSR/NIES). The CCM calculations are performed with the two ensemble members for REF1 scenario of the chemistry climate model validation (CCMVal) and the one ensemble member for the REF2 scenario. CCM simulates the development of the ozone hole from 1982 to 2000, as observed with a total ozone mapping spectrometer (TOMS), although the year-to-year variation is different from the observation owing to the internal variability of CCM and the ozone decreasing trends of CCM ozone in the two ensemble members of REF1 are underestimated. The trends in temperature and zonal mean zonal wind are analyzed and compared with the observations. There is consistency among the trends in zonal mean temperature, zonal mean zonal wind, and total ozone, but they differ among the ensemble members and observations. The diabatic heating rates and Eliassen-Palm flux fields are investigated in order to explain the differences. A delay trend in the breakup time of the Antarctic polar vortex is obtained for the period of 1980-1999 in the NCEP/NCAR and ERA40 data. A similar trend is also obtained from the CCM simulations, with statistical significance in one ensemble member of REF1 and REF2. Because the trends of the observations in the EP flux from the troposphere and its deposition in the lower stratosphere are consistent with an advanced breakup date of the polar vortex and because the trends of the CCM simulations are very small, it is likely that the Antarctic ozone depletion had some effect on the delay during the period 1980-1999. From 2000 to 2004, the NCEP/NCAR data show a large variation in breakup time, which makes the delay trend much less important. It is likely that the large variation in wave flux masked the effects of the ozone loss during that period. The two ensemble members of the REF1 simulation do not show such a dramatic change in the trend for the period 2000-2004, whereas REF2 shows a change in the trend for that period.

  10. Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Zukor, Dorothy J. (Technical Monitor)

    2000-01-01

    The Arctic Ocean is the smallest of the Earth's four major oceans, covering 14x10(exp 6) sq km located entirely within the Arctic Circle (66 deg 33 min N). It is a major player in the climate of the north polar region and has a variable sea ice cover that tends to increase its sensitivity to climate change. Its temperature, salinity, and ice cover have all undergone changes in the past several decades, although it is uncertain whether these predominantly reflect long-term trends, oscillations within the system, or natural variability. Major changes include a warming and expansion of the Atlantic layer, at depths of 200-900 m, a warming of the upper ocean in the Beaufort Sea, a considerable thinning (perhaps as high as 40%) of the sea ice cover, a lesser and uneven retreat of the ice cover (averaging approximately 3% per decade), and a mixed pattern of salinity increases and decreases.

  11. Evolution of Polarization Vortex Pairs in a Uniaxially Compressed Single-Crystal BaTiO3 Thin Film: From Initiation to Annihilation

    NASA Astrophysics Data System (ADS)

    Tian, Xiao Bao; Yang, Xin Hua; Wang, Peng

    2015-10-01

    Using the molecular dynamics method based on the shell model, a uniaxially compressed single-crystal BaTiO3 thin film with initial polarization configuration of double 90° domains has been simulated. Initiation and vertical propagation of domain switching induced by displacement loading lead to the occurrence of vortices and antivortices in pairs. However, further transverse extension results in separation between vortices and their corresponding antivortices of the same pair and the approach between vortices and antivortices of different pairs. As a result, a complete evolution process of the vortices and antivortices from initiation, to motion, then to collision, and finally to annihilation is observed. The internal mechanism of vortex- antivortex pair evolution is revealed.

  12. Polar stratospheric ozone: interactions with climate change, results from the EU project RECONCILE, and the 2010/11 Arctic ozone hole

    NASA Astrophysics Data System (ADS)

    von Hobe, Marc

    2013-04-01

    One of the most profound and well known examples of human impacts on atmospheric chemistry is the so called ozone hole. During the second half of the 20th century, anthropogenic emissions of chlorofluorocarbons (CFCs) led to a significant increase in stratospheric chlorine levels and hence the rate of ozone removal by catalytic cycles involving chlorine. While CFCs were essentially banned by the 1987 Montreal Protocol and its subsequent amendments, and stratospheric chlorine levels have recently started to decline again, another anthropogenic influence may at least delay the recovery of the stratospheric ozone layer: climate change, with little doubt a result of human emissions of carbon dioxide and other greenhouse gases, has led to changes in stratospheric temperature and circulation. The large ozone losses that typically occur in polar regions in spring are particularly affected by these changes. Here, we give an overview of the ozone-climate interactions affecting polar stratospheric ozone loss, and present latest results from the international research project RECONCILE funded by the European Commission. Remaining open questions will be discussed including the possible impacts of recently suggested geoengineering concepts to artificially enhance the stratospheric aerosol loading. A special focus will also be put on the 2010/11 Arctic winter that saw the first Arctic Ozone hole, including an impact study on surface UV radiation in the densely populated northern mid-latitudes.

  13. Aura Microwave Limb Sounder Observations of Dynamics and Transport During the Record-Breaking 2009 Arctic Stratospheric Major Warming

    NASA Technical Reports Server (NTRS)

    Manney, Gloria L.; Schwartz, Michael J.; Krueger, Kirstin; Santee, Michelle L.; Pawson, Steven; Lee, Jae N.; Daffer, William H.; Fuller, Ryan A.; Livesey, Nathaniel J.

    2009-01-01

    A major stratospheric sudden warming (SSW) in January 2009 was the strongest and most prolonged on record. Aura Microwave Limb Sounder (MLS) observations are used to provide an overview of dynamics and transport during the 2009 SSW, and to compare with the intense, long-lasting SSW in January 2006. The Arctic polar vortex split during the 2009 SSW, whereas the 2006 SSW was a vortex displacement event. Winds reversed to easterly more rapidly and reverted to westerly more slowly in 2009 than in 2006. More mixing of trace gases out of the vortex during the decay of the vortex fragments, and less before the fulfillment of major SSW criteria, was seen in 2009 than in 2006; persistent well-defined fragments of vortex and anticyclone air were more prevalent in 2009. The 2009 SSW had a more profound impact on the lower stratosphere than any previously observed SSW, with no significant recovery of the vortex in that region. The stratopause breakdown and subsequent reformation at very high altitude, accompanied by enhanced descent into a rapidly strengthening upper stratospheric vortex, were similar in 2009 and 2006. Many differences between 2006 and 2009 appear to be related to the different character of the SSWs in the two years.

  14. Is There an Arctic Ozone Hole?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.

    2000-01-01

    Total ozone observations from the Total Ozone Mapping Spectrometer (TOMS) instruments during March 1997 revealed an extensive region of low column densities in the Arctic region centered near the north pole. Values were below 250 Dobson units for nearly a two week period during this period, and were correlated with the position of the northern lower stratospheric polar vortex. The March 1997 average total ozone column densities were more than 30% lower than the average of column densities observed during the 1979-1982 March period. Both the northern spring seasons of 1998 and 1999 have shown much higher levels of total ozone. In this presentation, we will discuss the causes of the low total ozone values in 1997 and contrast those low values with the higher 1998 and 1999 observations. I will additionally discuss the just completed SOLVE campaign and the March 2000 ozone values.

  15. Arctic stratospheric dehydration - Part 1: Unprecedented observation of vertical redistribution of water

    NASA Astrophysics Data System (ADS)

    Khaykin, S. M.; Engel, I.; Vömel, H.; Formanyuk, I. M.; Kivi, R.; Korshunov, L. I.; Krämer, M.; Lykov, A. D.; Meier, S.; Naebert, T.; Pitts, M. C.; Santee, M. L.; Spelten, N.; Wienhold, F. G.; Yushkov, V. A.; Peter, T.

    2013-11-01

    We present high-resolution measurements of water vapour, aerosols and clouds in the Arctic stratosphere in January and February 2010 carried out by in situ instrumentation on balloon sondes and high-altitude aircraft combined with satellite observations. The measurements provide unparalleled evidence of dehydration and rehydration due to gravitational settling of ice particles. An extreme cooling of the Arctic stratospheric vortex during the second half of January 2010 resulted in a rare synoptic-scale outbreak of ice polar stratospheric clouds (PSCs) remotely detected by the lidar aboard the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) satellite. The widespread occurrence of ice clouds was followed by sedimentation and consequent sublimation of ice particles, leading to vertical redistribution of water inside the vortex. A sequence of balloon and aircraft soundings with chilled mirror and Lyman- ? hygrometers (Cryogenic Frostpoint Hygrometer, CFH; Fast In Situ Stratospheric Hygrometer, FISH; Fluorescent Airborne Stratospheric Hygrometer, FLASH) and backscatter sondes (Compact Optical Backscatter Aerosol Detector, COBALD) conducted in January 2010 within the LAPBIAT (Lapland Atmosphere-Biosphere Facility) and RECONCILE (Reconciliation of Essential Process Parameters for an Enhanced Predictability of Arctic Stratospheric Ozone Loss and its Climate Interactions) campaigns captured various phases of this phenomenon: ice formation, irreversible dehydration and rehydration. Consistent observations of water vapour by these independent measurement techniques show clear signatures of irreversible dehydration of the vortex air by up to 1.6 ppmv in the 20-24 km altitude range and rehydration by up to 0.9 ppmv in a 1 km thick layer below. Comparison with space-borne Aura MLS (Microwave Limb Sounder) water vapour observations allow the spatiotemporal evolution of dehydrated air masses within the Arctic vortex to be derived and upscaled.

  16. Correlation of N sub 2 O and ozone in the southern polar vortex during the Airborne Antarctic Ozone Experiment

    SciTech Connect

    Strahan, S.E.; Loewenstein, M.; Podolske, J.R.; Starr, W.L.; Chan, K.R. ); Proffitt, M.H. Univ. of Colorado, Boulder ); Kelly, K.K. )

    1989-11-30

    N{sub 2}O mixing ratios, measured in situ by an airborne laser spectrometer (ATLAS), have been used along with in situ ozone measurements to determine the correlation of N{sub 2}O and ozone in the Antarctic stratosphere during the late austral winter. N{sub 2}O and ozone measurements on five transit flights between Ames Research Center, California (37{degree}N), and Punta Arenas, Chile (53{degree}S), were used to determine the correlation of N{sub 2}O and ozone between 13 and 20 km in the mid-latitudes. The mid-latitude correlation is negative ({le} {minus}0.5). However, poleward of 53{degree}S, N{sub 2}O and ozone often show a strong positive correlation which approximately coincides with the wind speed maximum surrounding the Antarctic vortex. Strong zonal winds appearing between 60{degree}S and 70{degree}S are colocated with strong potential vorticity gradients, indicating that the wind speed maximum is a good marker for the vortex boundary. Flight tracks penetrating well beyond the wind maximum show a return to negative correlation. With few exceptions, regions in the vortex with a positive N{sub 2}O and O{sub 3} correlation are colocated with total water mixing ratios of greater than 2.9 ppmv, and negatively correlated regions with water mixing ratios of less than 2.9 ppmv. The driest regions appear to be colocated with the greatest ozone loss. Because positive correlation between N{sub 2}O and O{sub 3} cannot be explained by horizontal or vertical transport (below 35 km), positive N{sub 2}O and O{sub 3} correlations appear to be a sensitive indicator of chemical loss of ozone.

  17. Why unprecedented ozone loss in the Arctic in 2011? Is it related to climate change?

    NASA Astrophysics Data System (ADS)

    Pommereau, J.-P.; Goutail, F.; Lefèvre, F.; Pazmino, A.; Adams, C.; Dorokhov, V.; Eriksen, P.; Kivi, R.; Stebel, K.; Zhao, X.; van Roozendael, M.

    2013-05-01

    An unprecedented ozone loss occurred in the Arctic in spring 2011. The details of the event are revisited from the twice-daily total ozone and NO2 column measurements of the eight SAOZ/NDACC (Système d'Analyse par Observation Zénithale/Network for Detection of Atmospheric Composition Changes) stations in the Arctic. It is shown that the total ozone depletion in the polar vortex reached 38% (approx. 170 DU) by the end of March, which is larger than the 30% of the previous record in 1996. Aside from the long extension of the cold stratospheric NAT PSC period, the amplitude of the event is shown to be resulting from a record daily total ozone loss rate of 0.7% d-1 after mid-February, never seen before in the Arctic but similar to that observed in the Antarctic over the last 20 yr. This high loss rate is attributed to the absence of NOx in the vortex until the final warming, in contrast to all previous winters where, as shown by the early increase of NO2 diurnal increase, partial renoxification occurs by import of NOx or HNO3 from the outside after minor warming episodes, leading to partial chlorine deactivation. The cause of the absence of renoxification and thus of high loss rate, is attributed to a vortex strength similar to that of the Antarctic but never seen before in the Arctic. The total ozone reduction on 20 March was identical to that of the 2002 Antarctic winter, which ended around 20 September, and a 15-day extension of the cold period would have been enough to reach the mean yearly amplitude of the Antarctic ozone hole. However there is no sign of trend since 1994, either in PSC (polar stratospheric cloud) volume (volume of air cold enough to allow formation of PSCs), early winter denitrification, late vortex renoxification, and vortex strength or in total ozone loss. The unprecedented large Arctic ozone loss in 2011 appears to result from an extreme meteorological event and there is no indication of possible strengthening related to climate change.

  18. Extensive sampling of polar bears (Ursus maritimus) in the Northwest Passage (Canadian Arctic Archipelago) reveals population differentiation across multiple spatial and temporal scales

    PubMed Central

    Campagna, Leonardo; Van Coeverden de Groot, Peter J; Saunders, Brenda L; Atkinson, Stephen N; Weber, Diana S; Dyck, Markus G; Boag, Peter T; Lougheed, Stephen C

    2013-01-01

    As global warming accelerates the melting of Arctic sea ice, polar bears (Ursus maritimus) must adapt to a rapidly changing landscape. This process will necessarily alter the species distribution together with population dynamics and structure. Detailed knowledge of these changes is crucial to delineating conservation priorities. Here, we sampled 361 polar bears from across the center of the Canadian Arctic Archipelago spanning the Gulf of Boothia (GB) and M'Clintock Channel (MC). We use DNA microsatellites and mitochondrial control region sequences to quantify genetic differentiation, estimate gene flow, and infer population history. Two populations, roughly coincident with GB and MC, are significantly differentiated at both nuclear (FST = 0.01) and mitochondrial (?ST = 0.47; FST = 0.29) loci, allowing Bayesian clustering analyses to assign individuals to either group. Our data imply that the causes of the mitochondrial and nuclear genetic patterns differ. Analysis of mtDNA reveals the matrilineal structure dates at least to the Holocene, and is common to individuals throughout the species’ range. These mtDNA differences probably reflect both genetic drift and historical colonization dynamics. In contrast, the differentiation inferred from microsatellites is only on the scale of hundreds of years, possibly reflecting contemporary impediments to gene flow. Taken together, our data suggest that gene flow is insufficient to homogenize the GB and MC populations and support the designation of GB and MC as separate polar bear conservation units. Our study also provide a striking example of how nuclear DNA and mtDNA capture different aspects of a species demographic history. PMID:24102001

  19. Extensive sampling of polar bears (Ursus maritimus) in the Northwest Passage (Canadian Arctic Archipelago) reveals population differentiation across multiple spatial and temporal scales.

    PubMed

    Campagna, Leonardo; Van Coeverden de Groot, Peter J; Saunders, Brenda L; Atkinson, Stephen N; Weber, Diana S; Dyck, Markus G; Boag, Peter T; Lougheed, Stephen C

    2013-09-01

    As global warming accelerates the melting of Arctic sea ice, polar bears (Ursus maritimus) must adapt to a rapidly changing landscape. This process will necessarily alter the species distribution together with population dynamics and structure. Detailed knowledge of these changes is crucial to delineating conservation priorities. Here, we sampled 361 polar bears from across the center of the Canadian Arctic Archipelago spanning the Gulf of Boothia (GB) and M'Clintock Channel (MC). We use DNA microsatellites and mitochondrial control region sequences to quantify genetic differentiation, estimate gene flow, and infer population history. Two populations, roughly coincident with GB and MC, are significantly differentiated at both nuclear (F ST = 0.01) and mitochondrial (?ST = 0.47; F ST = 0.29) loci, allowing Bayesian clustering analyses to assign individuals to either group. Our data imply that the causes of the mitochondrial and nuclear genetic patterns differ. Analysis of mtDNA reveals the matrilineal structure dates at least to the Holocene, and is common to individuals throughout the species' range. These mtDNA differences probably reflect both genetic drift and historical colonization dynamics. In contrast, the differentiation inferred from microsatellites is only on the scale of hundreds of years, possibly reflecting contemporary impediments to gene flow. Taken together, our data suggest that gene flow is insufficient to homogenize the GB and MC populations and support the designation of GB and MC as separate polar bear conservation units. Our study also provide a striking example of how nuclear DNA and mtDNA capture different aspects of a species demographic history. PMID:24102001

  20. Assessment of neurotoxic effects of mercury in beluga whales (Delphinapterus leucas), ringed seals (Pusa hispida), and polar bears (Ursus maritimus) from the Canadian Arctic.

    PubMed

    Krey, Anke; Ostertag, Sonja K; Chan, Hing Man

    2015-03-15

    Marine mammals are indicator species of the Arctic ecosystem and an integral component of the traditional Inuit diet. The potential neurotoxic effects of increased mercury (Hg) in beluga whales (Delphinapterus leucas), ringed seals (Pusa hispida), and polar bears (Ursus maritimus) are not clear. We assessed the risk of Hg-associated neurotoxicity to these species by comparing their brain Hg concentrations with threshold concentrations for toxic endpoints detected in laboratory animals and field observations: clinical symptoms (>6.75 mg/kg wet weight (ww)), neuropathological signs (>4 mg/kg ww), neurochemical changes (>0.4 mg/kg ww), and neurobehavioral changes (>0.1mg/kg ww). The total Hg (THg) concentrations in the cerebellum and frontal lobe of ringed seals and polar bears were <0.5mg/kg ww, whereas the average concentration in beluga whale brain was >3mg/kg ww. Our results suggest that brain THg levels in polar bears are below levels that induce neurobehavioral effects as reported in the literature, while THg concentrations in ringed seals are within the range that elicit neurobehavioral effects and individual ringed seals exceed the threshold for neurochemical changes. The relatively high THg concentration in beluga whales exceeds all of the neurotoxicity thresholds assessed. High brain selenium (Se):Hg molar ratios were observed in all three species, suggesting that Se could protect the animals from Hg-associated neurotoxicity. This assessment was limited by several factors that influence neurotoxic effects in animals, including: animal species; form of Hg in the brain; and interactions with modifiers of Hg-associated toxicity, such as Se. Comparing brain Hg concentrations in wildlife with concentrations of appropriate laboratory studies can be used as a tool for risk characterization of the neurotoxic effects of Hg in Arctic marine mammals. PMID:24958011

  1. Life in a temperate Polar sea: a unique taphonomic window on the structure of a Late Cretaceous Arctic marine ecosystem

    PubMed Central

    Chin, Karen; Bloch, John; Sweet, Arthur; Tweet, Justin; Eberle, Jaelyn; Cumbaa, Stephen; Witkowski, Jakub; Harwood, David

    2008-01-01

    As the earth faces a warming climate, the rock record reminds us that comparable climatic scenarios have occurred before. In the Late Cretaceous, Arctic marine organisms were not subject to frigid temperatures but still contended with seasonal extremes in photoperiod. Here, we describe an unusual fossil assemblage from Devon Island, Arctic Canada, that offers a snapshot of a ca 75?Myr ago marine palaeoecosystem adapted to such conditions. Thick siliceous biogenic sediments and glaucony sands reveal remarkably persistent high primary productivity along a high-latitude Late Cretaceous coastline. Abundant fossil faeces demonstrate that this planktonic bounty supported benthic invertebrates and large, possibly seasonal, vertebrates in short food chains. These ancient organisms filled trophic roles comparable to those of extant Arctic species, but there were fundamental differences in resource dynamics. Whereas most of the modern Arctic is oligotrophic and structured by resources from melting sea ice, we suggest that forested terrestrial landscapes helped support the ancient marine community through high levels of terrigenous organic input. PMID:18713718

  2. QBO Influence on Polar Stratospheric Variability in the GEOS Chemistry-Climate Model

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Oman, L. D.; Li, F.; Slong, I.-S.; Newman, P. A.; Nielsen, J. E.

    2010-01-01

    The quasi-biennial oscillation modulates the strength of both the Arctic and Antarctic stratospheric vortices. Model and observational studies have found that the phase and characteristics of the quasi-biennial oscillation (QBO) contribute to the high degree of variability in the Arctic stratosphere in winter. While the Antarctic stratosphere is less variable, recent work has shown that Southern Hemisphere planetary wave driving increases in response to "warm pool" El Nino events that are coincident with the easterly phase of the QBO. These events hasten the breakup of the Antarctic polar vortex. The Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) is now capable of generating a realistic QBO, due a new parameterization of gravity wave drag. In this presentation, we will use this new model capability to assess the influence of the QBO on polar stratospheric variability. Using simulations of the recent past, we will compare the modeled relationship between QBO phase and mid-winter vortex strength with the observed Holton-Tan relation, in both hemispheres. We will use simulations of the 21 St century to estimate future trends in the relationship between QBO phase and vortex strength. In addition, we will evaluate the combined influence of the QBO and El Nino/Southern Oscillation (ENSO) on the timing of the breakup of the polar stratospheric vortices in the GEOS CCM. We will compare the influence of these two natural phenomena with trends in the vortex breakup associated with ozone recovery and increasing greenhouse gas concentrations.

  3. Detrital zircons (U-Pb and Lu-Hf) and host hemipelagic sediments (Pb-Sr-Nd-Os) from the Polar Arctic

    NASA Astrophysics Data System (ADS)

    Kapitonov, Igor; Belyatsky, Boris; Petrov, Eugeny; Sergeev, Sergey

    2015-04-01

    We studied deep-sea sediments from 6 sampling sites on the steep slopes of seamounts that accumulate during the last one million years. The goal of the study - to characterize the bedrock, which are coming to the surface from the overlying deposits for most of these steep slopes and weathering give talus deposits accumulating at the foot of the slopes.. The result proved to be similar enough for heavy fraction of all sediment columns spaced along the Alpha-Mendeleev Ridge on a 450 km. This suggest provenance similarity, which can be achieved either by erosion of the same rocks composing this ridge or by continental origin of material. We conducted control sampling of deep-water pelagic sediments in several remote places and held various positions with respect to the morphological ocean structure: on the flatten top surface of the deep-water ridge, on the bottom surface of the Amundsen Basin, 100 km to the west of the Lomonosov Ridge, at the Geophysicists Spur from the eastern side of the Lomonosov Ridge, and from the Laptev Sea. There are five control samples, which showed some local differences in the composition and distribution of zircon ages, with a total general similarity of these distributions. This fact indicates move the character of precipitation, as on the surface elevations and depressions in the sediment at the expense of local erosion of bedrock can not be formed. One of the sources of the Arctic Ocean sediments are traditionally considered «dirty» sea ice carrying material from the Canadian Archipelago, which are moved into the central part of the ocean due to Bofourt Gear flow. However, the distribution of zircon ages, revealed in the sediments, differs significantly from similar distributions for detrital zircon of Arctic coast of Alaska, the Canadian Archipelago, Greenland, Europe (Baltic Shield) and North America. But there are a lot more similarities with the zircon ages distributions typical for Asian continent, excluding China and India. However, a direct resemblance to the Permo-Triassic and Jurassic sandstones of coastal areas of the Arctic, we also do not see. Another factor in the formation of deep marine sediments is fluvial transference. The total input of the Arctic rivers reaches about 1x106 tonnes per year. When comparing the characteristics of detrital zircons of different river systems, we see that the similar is the distribution of zircon ages from the deposits of the Lena, Yenisei and Yana-Indigirka. Given that the Laptev Sea is the main source of «dirty» sea ice, carried by Transpolar Drift in the central part of the Arctic Ocean, detrital zircons from sediments of Lena river, which is characterized by the highest among Arctic rivers discharge, apparently, ensure the formation of the heavy fraction of hemipelagic mud in a large deep-water area of the Arctic Ocean, including the polar region. The observed variations in local distribution of zircon ages in the studied sampling points do not exclude the presence of local material, but to determine its share and establish with certainty the composition further research is required.

  4. Vulcanized Vortex

    E-print Network

    Cho, Inyong

    2008-01-01

    We investigate vortex configurations with the "vulcanization" term introduced for renormalization of $\\phi_\\star^4$ theory in canonical $\\theta$-deformed noncommutativity. In the small-$\\theta$ limit, we perform numerical calculations and find that nontopological vortex solutions exist as well as Q-ball type solutions, but topological vortex solutions are not admitted.

  5. Airborne Arctic Stratospheric Expedition 2: Air Parcel Trajectories

    NASA Technical Reports Server (NTRS)

    1993-01-01

    An overview of Airborne Arctic Stratospheric Expedition 2 is given. Effects of Pinatubo aerosol on stratospheric ozone at mid-latitudes, in situ measurements of ClO and ClO/HCl ratio, balloon-borne measurements of ClO, NO, and O3 in a volcanic cloud, and new observations of the NO(y)/N2O correlation in the lower stratosphere are discussed. Among other topics addressed are the following: in situ tracer correlations of methane, nitrous oxide, and ozone as observed aboard the DC-8, in situ measurements of changes in stratospheric aerosol and the N2O-aerosol relationship inside and outside of the polar vortex, measurements of halogenated organic compounds near the tropical tropopause, and airborne brightness measurements of the polar winter troposphere.

  6. Development of a Polar Stratospheric Cloud Model within the Community Earth System Model using constraints on Type I PSCs from the 2010-2011 Arctic winter

    NASA Astrophysics Data System (ADS)

    Zhu, Yunqian; Toon, Owen B.; Lambert, Alyn; Kinnison, Douglas E.; Brakebusch, Matthias; Bardeen, Charles G.; Mills, Michael J.; English, Jason M.

    2015-06-01

    Polar stratospheric clouds (PSCs) are critical elements of Arctic and Antarctic ozone depletion. We establish a PSC microphysics model using coupled chemistry, climate, and microphysics models driven by specific dynamics. We explore the microphysical formation and evolution of STS (Supercooled Ternary Solution) and NAT (Nitric Acid Trihydrate). Characteristics of STS particles dominated by thermodynamics compare well with observations. For example, the mass of STS is close to the thermodynamic equilibrium assumption when the particle surface area is >4 µm2/cm3. We derive a new nucleation rate equation for NAT based on observed denitrification in the 2010-2011 Arctic winter. The homogeneous nucleation scheme leads to supermicron NAT particles as observed. We also find that as the number density of NAT particles increases, the denitrification also increases. Simulations of the PSC lidar backscatter, denitrification, and gas phase species are generally within error bars of the observations. However, the simulations are very sensitive to temperature, which limits our ability to fully constrain some parameters (e.g., denitrification, ozone amount) based on observations.

  7. Contamination of food by crude oil affects food selection and growth performance, but not appetite, in an Arctic fish the polar cod (Boreogadus saida)

    SciTech Connect

    Christiansen, J.S.; George, S.G.

    1995-04-01

    The polar cod (Boreogadus saida) is recognized as a key species in Arctic marine food webs and it may, therefore, be important for the transfer of xenobiotics from lower trophic levels to its main predators, birds and sea mammals. The present work examines the effects of foods contaminated with 200 or 400 ppm crude oil on food selection patterns and appetite-growth relationship in polar cod using X-radiography. It is shown that sexually mature polar cod consumed mixtures of uncontaminated and oil-contaminated foods, and did not show a reduced overall appetite as compared with fish provided with uncontaminated food only. Food selection was, however, influenced by both sex and individual appetite. Male fish selected uncontaminated food when appetite was low, whereas females ingested contaminated and uncontaminated foods equally, irrespective of appetite level. The ingestion of oil-contaminated food led to a significant depression in growth performance in both male and female fish. Food contaminated with oil at a concentration of 500 ppm was completely rejected by both sexes. 6 refs., 4 figs., 2 tabs.

  8. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing. (Invited)

    NASA Astrophysics Data System (ADS)

    Marshall, J.; Ferreira, D.; Bitz, C. M.

    2013-12-01

    In recent decades the Arctic has been warming with sea ice disappearing. But the Antarctic has been (mainly) cooling and sea ice is growing. We argue here that inter-hemispheric asymmetries in the mean ocean circulation, with sinking in the northern north Atlantic and upwelling around Antarctica, strongly influences the surface response to GHG forcing, accelerating warming in the Arctic and delaying it in the Antarctic. Moreover, while GHG forcing has been qualitatively similar at the poles, ozone depletion only occurs in the Antarctic. The coupled atmosphere-ocean response to ozone depletion may further help to explain the Antarctic trends. A framework is presented to quantify the processes at work built around `Climate Response Functions' for GHG and Ozone-hole forcing.

  9. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing.

    PubMed

    Marshall, John; Armour, Kyle C; Scott, Jeffery R; Kostov, Yavor; Hausmann, Ute; Ferreira, David; Shepherd, Theodore G; Bitz, Cecilia M

    2014-07-13

    In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries in the mean ocean circulation, with sinking in the northern North Atlantic and upwelling around Antarctica, strongly influence the sea-surface temperature (SST) response to anthropogenic greenhouse gas (GHG) forcing, accelerating warming in the Arctic while delaying it in the Antarctic. Furthermore, while the amplitude of GHG forcing has been similar at the poles, significant ozone depletion only occurs over Antarctica. We suggest that the initial response of SST around Antarctica to ozone depletion is one of cooling and only later adds to the GHG-induced warming trend as upwelling of sub-surface warm water associated with stronger surface westerlies impacts surface properties. We organize our discussion around 'climate response functions' (CRFs), i.e. the response of the climate to 'step' changes in anthropogenic forcing in which GHG and/or ozone-hole forcing is abruptly turned on and the transient response of the climate revealed and studied. Convolutions of known or postulated GHG and ozone-hole forcing functions with their respective CRFs then yield the transient forced SST response (implied by linear response theory), providing a context for discussion of the differing warming/cooling trends in the Arctic and Antarctic. We speculate that the period through which we are now passing may be one in which the delayed warming of SST associated with GHG forcing around Antarctica is largely cancelled by the cooling effects associated with the ozone hole. By mid-century, however, ozone-hole effects may instead be adding to GHG warming around Antarctica but with diminished amplitude as the ozone hole heals. The Arctic, meanwhile, responding to GHG forcing but in a manner amplified by ocean heat transport, may continue to warm at an accelerating rate. PMID:24891392

  10. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing

    PubMed Central

    Marshall, John; Armour, Kyle C.; Scott, Jeffery R.; Kostov, Yavor; Hausmann, Ute; Ferreira, David; Shepherd, Theodore G.; Bitz, Cecilia M.

    2014-01-01

    In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries in the mean ocean circulation, with sinking in the northern North Atlantic and upwelling around Antarctica, strongly influence the sea-surface temperature (SST) response to anthropogenic greenhouse gas (GHG) forcing, accelerating warming in the Arctic while delaying it in the Antarctic. Furthermore, while the amplitude of GHG forcing has been similar at the poles, significant ozone depletion only occurs over Antarctica. We suggest that the initial response of SST around Antarctica to ozone depletion is one of cooling and only later adds to the GHG-induced warming trend as upwelling of sub-surface warm water associated with stronger surface westerlies impacts surface properties. We organize our discussion around ‘climate response functions’ (CRFs), i.e. the response of the climate to ‘step’ changes in anthropogenic forcing in which GHG and/or ozone-hole forcing is abruptly turned on and the transient response of the climate revealed and studied. Convolutions of known or postulated GHG and ozone-hole forcing functions with their respective CRFs then yield the transient forced SST response (implied by linear response theory), providing a context for discussion of the differing warming/cooling trends in the Arctic and Antarctic. We speculate that the period through which we are now passing may be one in which the delayed warming of SST associated with GHG forcing around Antarctica is largely cancelled by the cooling effects associated with the ozone hole. By mid-century, however, ozone-hole effects may instead be adding to GHG warming around Antarctica but with diminished amplitude as the ozone hole heals. The Arctic, meanwhile, responding to GHG forcing but in a manner amplified by ocean heat transport, may continue to warm at an accelerating rate. PMID:24891392

  11. Microplastics in Arctic polar waters: the first reported values of particles in surface and sub-surface samples

    PubMed Central

    Lusher, Amy L.; Tirelli, Valentina; O’Connor, Ian; Officer, Rick

    2015-01-01

    Plastic, as a form of marine litter, is found in varying quantities and sizes around the globe from surface waters to deep-sea sediments. Identifying patterns of microplastic distribution will benefit an understanding of the scale of their potential effect on the environment and organisms. As sea ice extent is reducing in the Arctic, heightened shipping and fishing activity may increase marine pollution in the area. Microplastics may enter the region following ocean transport and local input, although baseline contamination measurements are still required. Here we present the first study of microplastics in Arctic waters, south and southwest of Svalbard, Norway. Microplastics were found in surface (top 16?cm) and sub-surface (6?m depth) samples using two independent techniques. Origins and pathways bringing microplastic to the Arctic remain unclear. Particle composition (95% fibres) suggests they may either result from the breakdown of larger items (transported over large distances by prevailing currents, or derived from local vessel activity), or input in sewage and wastewater from coastal areas. Concurrent observations of high zooplankton abundance suggest a high probability for marine biota to encounter microplastics and a potential for trophic interactions. Further research is required to understand the effects of microplastic-biota interaction within this productive environment. PMID:26446348

  12. Microplastics in Arctic polar waters: the first reported values of particles in surface and sub-surface samples.

    PubMed

    Lusher, Amy L; Tirelli, Valentina; O'Connor, Ian; Officer, Rick

    2015-01-01

    Plastic, as a form of marine litter, is found in varying quantities and sizes around the globe from surface waters to deep-sea sediments. Identifying patterns of microplastic distribution will benefit an understanding of the scale of their potential effect on the environment and organisms. As sea ice extent is reducing in the Arctic, heightened shipping and fishing activity may increase marine pollution in the area. Microplastics may enter the region following ocean transport and local input, although baseline contamination measurements are still required. Here we present the first study of microplastics in Arctic waters, south and southwest of Svalbard, Norway. Microplastics were found in surface (top 16?cm) and sub-surface (6?m depth) samples using two independent techniques. Origins and pathways bringing microplastic to the Arctic remain unclear. Particle composition (95% fibres) suggests they may either result from the breakdown of larger items (transported over large distances by prevailing currents, or derived from local vessel activity), or input in sewage and wastewater from coastal areas. Concurrent observations of high zooplankton abundance suggest a high probability for marine biota to encounter microplastics and a potential for trophic interactions. Further research is required to understand the effects of microplastic-biota interaction within this productive environment. PMID:26446348

  13. Microplastics in Arctic polar waters: the first reported values of particles in surface and sub-surface samples

    NASA Astrophysics Data System (ADS)

    Lusher, Amy L.; Tirelli, Valentina; O'Connor, Ian; Officer, Rick

    2015-10-01

    Plastic, as a form of marine litter, is found in varying quantities and sizes around the globe from surface waters to deep-sea sediments. Identifying patterns of microplastic distribution will benefit an understanding of the scale of their potential effect on the environment and organisms. As sea ice extent is reducing in the Arctic, heightened shipping and fishing activity may increase marine pollution in the area. Microplastics may enter the region following ocean transport and local input, although baseline contamination measurements are still required. Here we present the first study of microplastics in Arctic waters, south and southwest of Svalbard, Norway. Microplastics were found in surface (top 16?cm) and sub-surface (6?m depth) samples using two independent techniques. Origins and pathways bringing microplastic to the Arctic remain unclear. Particle composition (95% fibres) suggests they may either result from the breakdown of larger items (transported over large distances by prevailing currents, or derived from local vessel activity), or input in sewage and wastewater from coastal areas. Concurrent observations of high zooplankton abundance suggest a high probability for marine biota to encounter microplastics and a potential for trophic interactions. Further research is required to understand the effects of microplastic-biota interaction within this productive environment.

  14. Physiologically-based pharmacokinetic modelling of immune, reproductive and carcinogenic effects from contaminant exposure in polar bears (Ursus maritimus) across the Arctic.

    PubMed

    Dietz, Rune; Gustavson, Kim; Sonne, Christian; Desforges, Jean-Pierre; Rigét, Frank F; Pavlova, Viola; McKinney, Melissa A; Letcher, Robert J

    2015-07-01

    Polar bears (Ursus maritimus) consume large quantities of seal blubber and other high trophic marine mammals and consequently have some of the highest tissue concentrations of organohalogen contaminants (OHCs) among Arctic biota. In the present paper we carried out a risk quotient (RQ) evaluation on OHC-exposed polar bears harvested from 1999 to 2008 and from 11 circumpolar subpopulations spanning from Alaska to Svalbard in order to evaluate the risk of OHC-mediated reproductive effects (embryotoxicity, teratogenicity), immunotoxicity and carcinogenicity (genotoxicity). This RQ evaluation was based on the Critical Body Residue (CBR) concept and a Physiologically-Based Pharmacokinetic Modelling (PBPK) approach using OHC concentrations measured in polar bear adipose or liver tissue. The range of OHC concentrations within polar bear populations were as follows for adipose, sum polychlorinated biphenyls ?PCBs (1797-10,537 ng/g lw), sum methylsulphone-PCB ?MeSO2-PCBs (110-672 ng/g lw), sum chlordanes ?CHLs (765-3477 ng/g lw), ?-hexachlorocyclohexane ?-HCH (8.5-91.3 ng/g lw), ?-hexachlorocyclohexane ?-HCH (65.5-542 ng/g lw), sum chlorbenzenes ?ClBzs (145-304 ng/g lw), dichlorodiphenyltrichloroethane ?DDTs (31.5-206 ng/g lw), dieldrin (69-249 ng/g lw), polybrominated diphenyl ethers ?PBDEs (4.6-78.4 ng/g lw). For liver, the perfluorooctanesulfonic acid (PFOS) concentrations ranged from 231-2792 ng/g ww. The total additive RQ from all OHCs ranged from 4.3 in Alaska to 28.6 in East Greenland bears for effects on reproduction, immune health and carcinogenicity, highlighting the important result that the toxic effect threshold (i.e. RQ>1) was exceeded for all polar bear populations assessed. PCBs were the main contributors for all three effect categories, contributing from 70.6% to 94.3% of the total risk and a RQ between 3.8-22.5. ?MeSO2-PCBs were the second highest effect contributor for reproductive and immunological effects (0.17polar bears. We therefore suggest that Critical Daily Doses (CDD) should be investigated in "ex vivo" dose-response studies on polar bears to replace laboratory studies on rats (Rattus rattus) to reveal whether high RQs are maintained. PMID:25825130

  15. Arctic ozone depletion in 2002-2003 measured by ASUR and comparison with POAM observations

    NASA Astrophysics Data System (ADS)

    Kuttippurath, Jayanarayanan; KleinböHl, Armin; Sinnhuber, Miriam; Bremer, Holger; Küllmann, Harry; Notholt, Justus; Godin-Beekmann, Sophie; Tripathi, Omprakash; Nikulin, Grigory

    2011-11-01

    We present ozone loss estimated from airborne measurements taken during January-February and March in the Arctic winter 2002/2003. The first half of the winter was characterized by unusually cold temperatures and the second half by a major stratospheric sudden warming around 15-18 January 2003. The potential vorticity maps show a vortex split in the lower stratosphere during the major warming (MW) in late January and during the minor warming in mid-February due to wave 1 amplification. However, the warming can be termed as a vortex displacement event as there was no vortex split during the MW period at 10 hPa. Very low temperatures, large areas of polar stratospheric clouds (PSCs), and high chlorine activation triggered significant ozone loss in the early winter, as the vortex moved to the midlatitude regions. The ozone depletion derived from the ASUR measurements sampled inside the vortex, in conjunction with the Mimosa-Chim model tracer, shows a maximum of 1.3 ± 0.2 ppmv at 450-500 K by late March. The partial column loss derived from the ASUR ozone profiles reaches up to 61 ± 4 DU in 400-550 K in the same period. The evolution of ozone and ozone loss assessed from the ASUR measurements is in very good agreement with POAM observations. The reduction in ozone estimated from the POAM measurements shows a similar maximum of 1.3 ± 0.2 ppmv at 400-500 K or 63 ± 4 DU in 400-550 K in late March. Our study reveals that the Arctic winter 2002/2003 was unique as it had three minor warmings and a MW, yet showed large loss in ozone. No such feature was observed in any other Arctic winter in the 1989-2010 period. In addition, an unusually large ozone loss in December, around 0.5 ± 0.2 ppmv at 450-500 K or 12 ± 1 DU in 400-550 K, was estimated for the first time in the Arctic. A careful and detailed diagnosis with all available published results for this winter exhibits an average ozone loss of 1.5 ± 0.3 ppmv at 450-500 K or 65 ± 5 DU in 400-550 K by the end of March, which exactly matches the ozone depletion derived from the ASUR, POAM and model data. The early ozone loss together with considerable loss afterwards put the warm Arctic winter 2002/2003 amongst the moderately cold winters in terms of the significance of the ozone loss.

  16. Why unprecedented ozone loss in the Arctic in 2011? Is it related to climatic change?

    NASA Astrophysics Data System (ADS)

    Pommereau, J.-P.; Goutail, F.; Lefèvre, F.; Pazmino, A.; Adams, C.; Dorokhov, V.; Eriksen, P.; Kivi, R.; Stebel, K.; Zhao, X.; van Rozendael, M.

    2013-01-01

    An unprecedented ozone loss occurred in the Arctic in spring 2011. The details of the event are re-visited from the twice-daily total ozone and NO2 columns measurements of the eight SAOZ/NDACC (Système d'Analyse par Observation Zénitale/Network for Detection of Atmospheric Composition Changes) stations in the Arctic. It is shown that the total ozone depletion in the polar vortex reached 38% (approx. 170 DU) by the end of March that is larger than the 30% of the previous record in 1996. Asides from the long extension of the cold stratospheric NAT PSC period, the amplitude of the event is shown to be resulting from a record daily total ozone loss rate of 0.7% day-1 after mid-February, never seen before in the Arctic but similar to that observed in the Antarctic over the last 20 yr. This high loss rate is attributed to the absence of NOx in the vortex until the final warming, in contrast to all previous winters where, as shown by the early increase of NO2 diurnal increase, partial renoxification is occurring by import of NOx or HNO3 from the outside after minor warming episodes, leading to partial chlorine deactivation. The cause of the absence of renoxification and thus of high loss rate, is attributed to a vortex strength similar to that of the Antarctic but never seen before in the Arctic. The total ozone reduction on 20 March was identical to that of the 2002 Antarctic winter, which ended around 20 September, and a 15-day extension of the cold period would have been enough to reach the mean yearly amplitude of the Antarctic ozone hole. However there is no sign of trend since 1994, neither in PSC volume, early winter denitrification, late vortex renoxification, and vortex strength nor in total ozone loss. The unprecedented large Arctic ozone loss in 2011 appears to resulting from an extreme meteorological event and there is no indication of possible strengthening related to climate change.

  17. The influence of polar heterogeneous processes on reactive chlorine at middle latitudes - Three dimensional model implications

    NASA Astrophysics Data System (ADS)

    Douglass, Anne R.; Rood, Richard B.; Kaye, Jack A.; Stolarki, Richard S.; Allen, Dale J.

    1991-01-01

    Three-dimensional model calculations with the NASA/GSFC chemistry and transport model have been designed to consider the impact of heterogeneous processes occurring on polar stratospheric clouds (PSCs) in the Arctic vortex on the HCl distribution. By examining the HCl concentration for a calculation with PSCs relative to a calculation with gas phase chemistry only, the impact of polar processing on reactive chlorine species at middle latitudes is inferred. Results from the chemistry and transport model reproduce basic features of the ClO measurements (Toohey et al., 1991), which were made on the ferry flights of the ER-2 from Stavanger, Norway to Moffett Field, California via Wallops Island, Virginia on February 20 and 21, 1989. The model indicates that perturbed air which is contained within the polar vortex during winter is not homogeneously mixed, and that the ferry flights were made through air with the largest conversion of HCl to reactive chlorine that is seen at middle latitudes.

  18. Polar stratospheric cloud climatology based on Stratospheric Aerosol Measurement II observations from 1978 to 1989

    NASA Technical Reports Server (NTRS)

    Poole, Lamont R.; Pitts, Michael C.

    1994-01-01

    The probability of polar stratospheric cloud (PSC) occurrence in the Antarctic and Arctic has been estimated using Stratospheric Aerosol Measurement (SAM) II aerosol extinction data from 1978 to 1989. Antarctic PSCs are typically observed by SAM II from mid-May to early November, with a maximum zonal average probability of about 0.6 at 18-20 km in August. The typical Arctic PSC season extends only from late November to early March, with a peak zonal average probability of about 0.1 in early February at 20-22 km. There is considerable year-to-year variability in Arctic PSC sightings because of changes in the dynamics of the northern polar vortex. Year-to-year variability in Antarctic sightings is most prominent in the number of late season clouds. Maximum PSC sighting probabilities in both polar regions occur in the region from 90 deg W through the Greenwich meridian to 90 deg E, where temperatures are coldest on average. Arctic sighting probabilities approach zero outside this region, but clouds have been sighted in the Antarctic at all longitudes during most months. Inferred PSC formation temperatures remain constant throughout the Arctic winter and are similar to those in early Antarctic winter. PSC formation temperatures in the Antarctic drop markedly in the 15 to 20-km region by September, a pattern consistent with the irreversible loss of HNO3 and H2O vapor in sedimenting PSC particles.

  19. Polar stratospheric cloud climatology based on Stratospheric Aerosol Measurement II observations from 1978 to 1989

    SciTech Connect

    Poole, L.R.; Pitts, M.C. |

    1994-06-01

    The probability of polar stratospheric cloud (PSC) occurrence in the Antarctic and Arctic has been estimated using Stratospheric Aerosol Measurement (SAM) II aerosol extinction data from 1978 to 1989. Antarctic PSCs are typically observed by SAM II from mid-May to early November, with a maximum zonal average probability of about 0.6 at 18-20 km in August. The typical Arctic PSC season extends only from late November to early March, with a peak zonal average probability of about 0.1 in early February at 20-22 km. There is considerable year-to-year variability in Arctic PSC sightings because of changes in the dynamics of the northern polar vortex. Year-to-year variability in Antarctic sightings is most prominent in the number of late season clouds. Maximum PSC sighting probabilities in both polar regions occur in the region from 90 deg W through the Greenwich meridian to 90 deg E, where temperatures are coldest on average. Arctic sighting probabilities approach zero outside this region, but clouds have been sighted in the Antarctic at all longitudes during most months. Inferred PSC formation temperatures remain constant throughout the Arctic winter and are similar to those in early Antarctic winter. PSC formation temperatures in the Antarctic drop markedly in the 15 to 20-km region by September, a pattern consistent with the irreversible loss of HNO3 and H2O vapor in sedimenting PSC particles.

  20. Changing Global Circumpolar Vortex

    NASA Astrophysics Data System (ADS)

    Choi, G.; Robinson, D. A.

    2013-12-01

    Observations and projections of the circumpolar vortex (CV) in both hemispheres are examined in the context of climate change. Long-term (1951~2100) maps and statistics of daily/monthly CV size, perimeter and circularity ratio (CR) are produced from the NCEP/NCAR reanalysis I (1951~present) and IPCC CMIP5 (present~2100) modeled 500hPa pressure data sets using Geographic Information System (GIS) methods. Analyses of daily/monthly data show that the size and perimeter of the Northern Hemisphere CV have shrunk, particularly in spring and summer, while pattern changes are not seen around the Antarctica. No obvious change in the CR of the CV in either hemisphere indicates that abnormal temperature events such as cold surges in winter and heat waves in summer around circumpolar regions still occur periodically in the recent warmer climate. Pattern changes observed in the Northern Hemisphere may be associated with the complexity of the land-ocean distribution and Arctic cryospheric feedbacks (e.g. the reduction of albedo due to melting Arctic sea ice and reduced continental snow cover). The absence of notable changes in the Southern Hemisphere may be due to less atmosphere warming or cryospheric changes over Antarctica and the Southern Ocean. Projected future CV characteristics will also be discussed in detail. Keywords: circumpolar vortex, cryospheric feedbacks, climate change, Geographic Information System (GIS)

  1. Simultaneous Bro and Oclo Profile Measurements In The Arctic Vortex; Implications For The Clo and Bro Chemistry and Inferred Ozone Loss From The Clo/bro Ozone Loss Cycle

    NASA Astrophysics Data System (ADS)

    Dorf, M.; Bösch, H.; Chipperfield, M.; Camy-Peyret, C.; Fitzenberger, R.; Payan, S.; Sinnhuber, B.; Weidner, F.; Pfeilsticker, K.

    During the EuroSolve campaign in winter 1999/2000, the LPMA/DOAS (Labora- toire de Physique Moleculaire et Applications/Differential Optical Absorption Spec- troscopy) balloon was lauched from Kiruna into the highly activated arctic vortex on Feb. 18, 2000. The azimuth-controlled balloon gondola carried three spectrometer, which performed solar occultation measurements in virtually at whole all wavelength from 320 nm into the mid-infrared. Line of sight absorption and profile of a suite of atmospheric gases (O3, NO2, BrO, OClO, IO, OIO, CH4, H2O, HCl, ClONO2, N2O,.....) were measured and compared with 3-D CTM and 1D trajectory models. The present paper reports on the simultaneous BrO, and OClO measurements. BrO concentrations of up 16.6+/-2 ppt - implying a total Bry of 23+/-2.5 ppt - , and OClO of up to 12+/-2 ppt (at 90 SZA) - implying ClOx = 1.8+/-0.2ppb - at 19 km were measured. These values are apparently compatible with the modeled and measured bromine and chlorine chemistry and budget. The BrO and OClO measurements allow us to infer ozone loss rates due to the ClO dimer cycle and the coupled BrO/ClO cy- cle, which are compared with inferred O3 loss rates. The OClO measured above 25 km (8+/- 2ppt), where NOx is found to be large (> 500 ppt), however, is much larger than what can be easily explained by present photochemistry. This finding points to a deficit in our understanding of the NOx/ClOx/BrOx coupling, a finding also reported previously from from SAOZ/LPMA and AMON. Various possibilites to solve that discrepancy and their potential for ozone chemistry will be discussed.

  2. Vulcanized Vortex

    E-print Network

    Inyong Cho; Youngone Lee

    2009-02-07

    We investigate vortex configurations with the "vulcanization" term inspired by the renormalization of $\\phi_\\star^4$ theory in the canonical $\\theta$-deformed noncommutativity. We focus on the classical limit of the theory described by a single parameter which is the ratio of the vulcanization and the noncommutativity parameters. We perform numerical calculations and find that nontopological vortex solutions exist as well as Q-ball type solutions, but topological vortex solutions are not admitted.

  3. Vulcanized vortex

    SciTech Connect

    Cho, Inyong; Lee, Youngone

    2009-01-15

    We investigate vortex configurations with the 'vulcanization' term inspired by the renormalization of {phi}{sub *}{sup 4} theory in the canonical {theta}-deformed noncommutativity. We focus on the classical limit of the theory described by a single parameter which is the ratio of the vulcanization and the noncommutativity parameters. We perform numerical calculations and find that nontopological vortex solutions exist as well as Q-ball type solutions, but topological vortex solutions are not admitted.

  4. Vulcanized vortex

    NASA Astrophysics Data System (ADS)

    Cho, Inyong; Lee, Youngone

    2009-01-01

    We investigate vortex configurations with the “vulcanization” term inspired by the renormalization of ??4 theory in the canonical ?-deformed noncommutativity. We focus on the classical limit of the theory described by a single parameter which is the ratio of the vulcanization and the noncommutativity parameters. We perform numerical calculations and find that nontopological vortex solutions exist as well as Q-ball type solutions, but topological vortex solutions are not admitted.

  5. Implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming Arctic

    USGS Publications Warehouse

    Peacock, Elizabeth; Sonsthagen, Sarah A.; Obbard, Martyn E.; Boltunov, Andrei N.; Regehr, Eric V.; Ovsyanikov, Nikita; Aars, Jon; Atkinson, Stephen N.; Sage, George K.; Hope, Andrew G.; Zeyl, Eve; Bachmann, Lutz; Ehrich, Dorothee; Scribner, Kim T.; Amstrup, Steven C.; Belikov, Stanislav; Born, Erik W.; Derocher, Andrew E.; Stirling, Ian; Taylor, Mitchell K.; Wiig, Øystein; Paetkau, David; Talbot, Sandra L.

    2015-01-01

    We provide an expansive analysis of polar bear (Ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. We sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. Characterizing their circumpolar genetic structure using microsatellite data, we defined four clusters that largely correspond to current ecological and oceanographic factors: Eastern Polar Basin, Western Polar Basin, Canadian Archipelago and Southern Canada. We document evidence for recent (ca. last 1–3 generations) directional gene flow from Southern Canada and the Eastern Polar Basin towards the Canadian Archipelago, an area hypothesized to be a future refugium for polar bears as climate-induced habitat decline continues. Our data provide empirical evidence in support of this hypothesis. The direction of current gene flow differs from earlier patterns of gene flow in the Holocene. From analyses of mitochondrial DNA, the Canadian Archipelago cluster and the Barents Sea subpopulation within the Eastern Polar Basin cluster did not show signals of population expansion, suggesting these areas may have served also as past interglacial refugia. Mismatch analyses of mitochondrial DNA data from polar and the paraphyletic brown bear (U. arctos) uncovered offset signals in timing of population expansion between the two species, that are attributed to differential demographic responses to past climate cycling. Mitogenomic structure of polar bears was shallow and developed recently, in contrast to the multiple clades of brown bears. We found no genetic signatures of recent hybridization between the species in our large, circumpolar sample, suggesting that recently observed hybrids represent localized events. Documenting changes in subpopulation connectivity will allow polar nations to proactively adjust conservation actions to continuing decline in sea-ice habitat.

  6. Implications of the Circumpolar Genetic Structure of Polar Bears for Their Conservation in a Rapidly Warming Arctic

    PubMed Central

    Peacock, Elizabeth; Sonsthagen, Sarah A.; Obbard, Martyn E.; Boltunov, Andrei; Regehr, Eric V.; Ovsyanikov, Nikita; Aars, Jon; Atkinson, Stephen N.; Sage, George K.; Hope, Andrew G.; Zeyl, Eve; Bachmann, Lutz; Ehrich, Dorothee; Scribner, Kim T.; Amstrup, Steven C.; Belikov, Stanislav; Born, Erik W.; Derocher, Andrew E.; Stirling, Ian; Taylor, Mitchell K.; Wiig, Øystein; Paetkau, David; Talbot, Sandra L.

    2015-01-01

    We provide an expansive analysis of polar bear (Ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. We sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. Characterizing their circumpolar genetic structure using microsatellite data, we defined four clusters that largely correspond to current ecological and oceanographic factors: Eastern Polar Basin, Western Polar Basin, Canadian Archipelago and Southern Canada. We document evidence for recent (ca. last 1–3 generations) directional gene flow from Southern Canada and the Eastern Polar Basin towards the Canadian Archipelago, an area hypothesized to be a future refugium for polar bears as climate-induced habitat decline continues. Our data provide empirical evidence in support of this hypothesis. The direction of current gene flow differs from earlier patterns of gene flow in the Holocene. From analyses of mitochondrial DNA, the Canadian Archipelago cluster and the Barents Sea subpopulation within the Eastern Polar Basin cluster did not show signals of population expansion, suggesting these areas may have served also as past interglacial refugia. Mismatch analyses of mitochondrial DNA data from polar and the paraphyletic brown bear (U. arctos) uncovered offset signals in timing of population expansion between the two species, that are attributed to differential demographic responses to past climate cycling. Mitogenomic structure of polar bears was shallow and developed recently, in contrast to the multiple clades of brown bears. We found no genetic signatures of recent hybridization between the species in our large, circumpolar sample, suggesting that recently observed hybrids represent localized events. Documenting changes in subpopulation connectivity will allow polar nations to proactively adjust conservation actions to continuing decline in sea-ice habitat. PMID:25562525

  7. Implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming Arctic.

    PubMed

    Peacock, Elizabeth; Sonsthagen, Sarah A; Obbard, Martyn E; Boltunov, Andrei; Regehr, Eric V; Ovsyanikov, Nikita; Aars, Jon; Atkinson, Stephen N; Sage, George K; Hope, Andrew G; Zeyl, Eve; Bachmann, Lutz; Ehrich, Dorothee; Scribner, Kim T; Amstrup, Steven C; Belikov, Stanislav; Born, Erik W; Derocher, Andrew E; Stirling, Ian; Taylor, Mitchell K; Wiig, Øystein; Paetkau, David; Talbot, Sandra L

    2015-01-01

    We provide an expansive analysis of polar bear (Ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. We sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. Characterizing their circumpolar genetic structure using microsatellite data, we defined four clusters that largely correspond to current ecological and oceanographic factors: Eastern Polar Basin, Western Polar Basin, Canadian Archipelago and Southern Canada. We document evidence for recent (ca. last 1-3 generations) directional gene flow from Southern Canada and the Eastern Polar Basin towards the Canadian Archipelago, an area hypothesized to be a future refugium for polar bears as climate-induced habitat decline continues. Our data provide empirical evidence in support of this hypothesis. The direction of current gene flow differs from earlier patterns of gene flow in the Holocene. From analyses of mitochondrial DNA, the Canadian Archipelago cluster and the Barents Sea subpopulation within the Eastern Polar Basin cluster did not show signals of population expansion, suggesting these areas may have served also as past interglacial refugia. Mismatch analyses of mitochondrial DNA data from polar and the paraphyletic brown bear (U. arctos) uncovered offset signals in timing of population expansion between the two species, that are attributed to differential demographic responses to past climate cycling. Mitogenomic structure of polar bears was shallow and developed recently, in contrast to the multiple clades of brown bears. We found no genetic signatures of recent hybridization between the species in our large, circumpolar sample, suggesting that recently observed hybrids represent localized events. Documenting changes in subpopulation connectivity will allow polar nations to proactively adjust conservation actions to continuing decline in sea-ice habitat. PMID:25562525

  8. Mapping Arctic circumpolar albedo at 250-m spatial resolution during International Polar Year by fusion of MODIS/TERRA land bands B1-B7

    NASA Astrophysics Data System (ADS)

    Trishchenko, Alexander; Luo, Yi; Khlopenkov, Konstantin; Park, William; Wang, Shusen

    The time series of spatially-enhanced MODIS surface albedo for the Arctic circumpolar zone (9,000km × 9,000km) are generated as the Canada Centre for Remote Sensing (CCRS) contribution to the Canadian component of the International Polar Year (IPY) Program. The imagery is obtained by a fusion of MODIS bands B1-B2 observed at 250-meter spatial resolution with bands B3-B7 observed at 500-meter spatial resolution to satisfy the Global Climate Observing System (GCOS) requirements for spatial resolution of satellite products for climate. The fusion method employed an adaptive regression and normalization to preserve the image radiometric properties. A new cloud and cloud shadow detection method and clear-sky compositing scheme were employed for the 250m multi-spectral data. Unlike standard MODIS products divided into separate thematic categories, this new product is spatially continuous over the entire circumpolar area and includes all surface types: land, ocean, snow/ice. New bi-directional reflectance distribution model based on POLDER multiangular observations is employed. This model accounts better for the hot-spot effect and makes distinction between surfaces covered by a canopy and surfaces with specular reflection, such as water and snow/ice. By the end of the IPY in 2009, a decade long (2000-2009) time series of these data at 10-day intervals will be available to document the state and variability of the Arctic region at high spatial and temporal resolution. This study is conducted at the Canada Centre for Remote Sensing (CCRS), Earth Sciences Sector of the Department of Natural Resources Canada as part of the Project J35 of the Program on "Enhancing Resilience in a Changing Climate" and the "Climate Change and Ecosystem Impact" Project supported by the Canadian Space Agency through the Government Related Initiatives Program (GRIP). The MODIS data were acquired through the NASA Distributed Active Archive Center (DAAC).

  9. Rapid development of arctic cyclone in June 2008 simulated by the cloud resolving global model NICAM

    NASA Astrophysics Data System (ADS)

    Aizawa, Takuro; Tanaka, H. L.; Satoh, Masaki

    2014-11-01

    In this study, we conducted a numerical simulation of a rapid development of an arctic cyclone (AC) that appeared in June 2008 using a cloud resolving global model, Nonhydrostatic ICosahedral Atmospheric Model (NICAM). We investigated the three dimensional structure and intensification mechanism of the simulated AC that developed to the minimum sea level pressure of 971 hPa in the model. According to the result, the AC indicates a barotropic structure with a warm core in the lower stratosphere and a cold core in the troposphere. The development of the AC is accompanied by an intense mesoscale cyclone (MC) showing baroclinic structure with a marked local arctic front. The upper level warm core of the AC is formed by an adiabatic heating associated with the downdraft in the lower stratosphere. The rapid development of the AC is caused by the combination of the intensification of the upper level warm core and the merging with the baroclinically growing MC in the lower level. The merging of the AC and MC and the vertical vortex coupling with the upper air polar vortex are the most important mechanisms for the rapid development of the arctic cyclone.

  10. In situ measurements of BrO in the Arctic stratosphere

    SciTech Connect

    Toohey, D.W.; Anderson, J.G. ); Brune, W.H. ); Chan, K.R. )

    1990-03-01

    Mixing ratios of BrO have been measured in the Arctic lower stratosphere with an instrument mounted on the NASA ER-2 aircraft. Observations from fourteen flights above the Arctic Circle in January and February of 1989 defined mixing ratios within the vortex of 4{plus minus}2 parts per trillion by volume (pptv) at a potential temperature of 400 K, rising to 8{plus minus}2 pptv at 470 K. These values are twice as large as values found at equivalent potential temperatures at lower latitudes, and are comparable to the mixing ratios found inside the Antarctic polar vortex. Within the statistical uncertainty of the measurements, no BrO was observed in darkness at any time either inside or outside of the vortex, indicating that active bromine was sequestered in long-lived reservoirs, probably BrONO{sub 2} and BrCl. These measurements, in conjunction with measurements of ClO, demonstrate that the interaction of bromine and chlorine could represent a major sink for ozone in the presence of sunlight.

  11. In situ measurements of BrO in the Arctic stratosphere

    NASA Technical Reports Server (NTRS)

    Toohey, D. W.; Anderson, J. G.; Brune, W. H.; Chan, K. R.

    1990-01-01

    Mixing ratios of BrO have been measured in the Arctic lower statosphere with an instrument mounted on the NASA ER-2 aircraft. Observations from fourteen flights above the Arctic Circle in January and February of 1989 defined mixing ratios within the vortex of 4 + or - 2 parts per trillion by volume (pptv) at a potential temperature of 400 K, rising to 8 + or - 2 pptv at 470 K. These values are twice as large as values found at equivalent potential temperatures at lower latitudes, and are comparable to the mixing ratios found inside the antarctic polar vortex. Within the statistical uncertainty of the measurements, no BrO was observed in darkness at any time either inside or outside of the vortex, indicating that active bromine was sequestered in long-lived reservoirs, probably BrONO2 and BrCl. These measurements, in conjuction with measurements of ClO, demonstrate that the interaction of bromine and chlorine could represent a major sink for ozone in the presence of sunlight.

  12. Surviving in the Arctic

    USGS Multimedia Gallery

    This image is of two polar bears cuddled together on a piece of Arctic sea ice, surrounded by ocean water and thin layers of sea ice. This image allows for a deeper understanding of the endangered species and highlights the need for USGS research to help in their protection. ...

  13. Polar Bear

    USGS Publications Warehouse

    Amstrup, S.D.; DeMaster

    1988-01-01

    Polar bears are long-lived, late-maturing carnivores that have relatively low rates of reproduction and natural mortality. Their populations are susceptible to disturbance from human activities, such as the exploration and development of mineral resources or hunting. Polar bear populations have been an important renewable resource available to coastal communities throughout the Arctic for thousands of years.

  14. Observation of stable-vector vortex solitons.

    PubMed

    Izdebskaya, Yana; Assanto, Gaetano; Krolikowski, Wieslaw

    2015-09-01

    We report on the first experimental observation of stable-vector vortex solitons in nonlocal nonlinear media with a reorientational response, such as nematic liquid crystals. These solitons consist of two co-polarized, mutually trapped beams of different colors, a bright fundamental spatial soliton, and a nonlinear optical vortex. The nonlinear vortex component, which is normally unstable in nonlinear media, is stabilized and confined here by the highly nonlocal refractive potential induced by the soliton. PMID:26368742

  15. A 3D simulation of the early winter distribution of reactive chlorine in the north polar vortex

    NASA Technical Reports Server (NTRS)

    Douglass, A.; Rood, R.; Waters, J.; Froidevaux, L.; Read, W.; Elson, L.; Geller, M.; Chi, Y.; Cerniglia, M.; Steenrod, S.

    1993-01-01

    Early in December 1991, high values of ClO are seen by the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite at latitudes south of areas of temperatures cold enough to form polar stratospheric clouds (PSCs). A 3D simulation shows that the heterogeneous conversion of chlorine reservoirs to reactive chlorine on the surfaces of PSCs (processing) takes place at high latitudes. Often the processed air must be transported to lower latitudes, where the reactive chlorine is photochemically converted to ClO, to be observed by MLS. In this simulation, one incidence of cold temperatures is associated with an anticyclone, and a second with a cyclone. The transport of processed air associated with the anticyclone is marked by shearing; a decrease in the maximum of the processed air is accompanied by growth of the area influenced by the processing. In contrast, the air processed in the cyclonic event spreads more slowly. This shows that transport and shearing is a crucial element to the evolution of reactive chlorine associated with a processing event. In particular, transport and shearing, as well as photochemical processes, can cause variations in observed ClO.

  16. Dynamics of the exceptional warming events during the Arctic winters 2003/04, 2005/06 and 2008/09

    NASA Astrophysics Data System (ADS)

    Kuttippurath, Jayanarayanan; Godin-Beekmann, Sophie; Lefèvre, Franck; Nikulin, Grigory

    2010-05-01

    Sudden stratospheric warmings (SSW) are common features of the Arctic meteorology. During a major SSW, polar temperature rises and the zonal mean flow weakens dramatically over a short period of time. This situation causes displacement, distortion or split of the polar vortex. The Arctic winters 2003/04, 2005/06 and 2008/09 were characterized by major midwinter warming of different proportions. The major warming occurred in early January in 2003/04 and in mid-January in the other winters in the lower stratosphere. The winter 2003/04 was remarkable in that a stable vortex formed again in March 2004 after two months of severe disturbance. No vortex was evident in other winters after the mid-January major warming. The planetary waves 1 and 2 play a key role in warming events and in vortex distortions as they control the stratospheric circulation. The dominating presence and amplitude of these waves were also different in each winter. In this presentation, we characterize the winters 2003/04, 2005/06 and 2008/09 in terms of chemical and dynamical situation during the winters. In order to illustrate, we exploit the heat flux, zonal wind characteristics, Eliassen-Palm vectors and planetary wave analyzes for the winters in a comparative perspective. The dynamical parameters are derived from ECMWF analyzes and the chemical realm are discussed in terms of the measurements from MLS (Microwave Limb Sounder) and POAM (Polar Ozone and Aerosol Measurement) as well as simulations from the Mimosa-Chim global three-dimensional chemical transport model.

  17. USGS Arctic science strategy

    USGS Publications Warehouse

    Shasby, Mark; Smith, Durelle

    2015-01-01

    The United States is one of eight Arctic nations responsible for the stewardship of a polar region undergoing dramatic environmental, social, and economic changes. Although warming and cooling cycles have occurred over millennia in the Arctic region, the current warming trend is unlike anything recorded previously and is affecting the region faster than any other place on Earth, bringing dramatic reductions in sea ice extent, altered weather, and thawing permafrost. Implications of these changes include rapid coastal erosion threatening villages and critical infrastructure, potentially significant effects on subsistence activities and cultural resources, changes to wildlife habitat, increased greenhouse-gas emissions from thawing permafrost, threat of invasive species, and opening of the Arctic Ocean to oil and gas exploration and increased shipping. The Arctic science portfolio of the U.S. Geological Survey (USGS) and its response to climate-related changes focuses on landscapescale ecosystem and natural resource issues and provides scientific underpinning for understanding the physical processes that shape the Arctic. The science conducted by the USGS informs the Nation's resource management policies and improves the stewardship of the Arctic Region.

  18. Live from the Arctic

    NASA Astrophysics Data System (ADS)

    Haines-Stiles, G.; Warnick, W. K.; Warburton, J.; Sunwood, K.

    2003-12-01

    For reasons of geography and geophysics, the poles of our planet, the Arctic and Antarctica, are places where climate change appears first: they are global canaries in the mine shaft. But while Antarctica (its penguins and ozone hole, for example) has been relatively well-documented in recent books, TV programs and journalism, the far North has received somewhat less attention. This project builds on and advances what has been done to date to share the people, places, and stories of the North with all Americans through multiple media, over several years. In a collaborative project between the Arctic Research Consortium of the United States (ARCUS) and PASSPORT TO KNOWLEDGE, Live from the Arctic will bring the Arctic environment to the public through a series of primetime broadcasts, live and taped programming, interactive virtual field trips, and webcasts. The five-year project will culminate during the 2007-2008 International Polar Year (IPY). Live from the Arctic will: A. Promote global understanding about the value and world -wide significance of the Arctic, B. Bring cutting-edge research to both non-formal and formal education communities, C. Provide opportunities for collaboration between arctic scientists, arctic communities, and the general public. Content will focus on the following four themes. 1. Pan-Arctic Changes and Impacts on Land (i.e. snow cover; permafrost; glaciers; hydrology; species composition, distribution, and abundance; subsistence harvesting) 2. Pan-Arctic Changes and Impacts in the Sea (i.e. salinity, temperature, currents, nutrients, sea ice, marine ecosystems (including people, marine mammals and fisheries) 3. Pan-Arctic Changes and Impacts in the Atmosphere (i.e. precipitation and evaporation; effects on humans and their communities) 4. Global Perspectives (i.e. effects on humans and communities, impacts to rest of the world) In The Earth is Faster Now, a recent collection of comments by members of indigenous arctic peoples, arctic residents speak in eloquent terms of the changes they see around them, manifested in new patterns of vegetation, the melting of permafrost and the absence of game species that used to be abundant. Meanwhile, new satellites and more sophisticated sensors on the ground and in the ice, add scientific testimony that seems to support and even extend native perceptions. Live from the Arctic will unify both perspectives, and use todays most powerful and effective communications media to connect young people and general audiences all across America to researchers and communities living and working in the Arctic. During IPY there will be a level of interest in the Polar regions unprecedented in a generation. Live from the Arctic offers unique resources to satisfy that curiosity, and encourage active participation and engagement in understanding some of Earths most significant peoples, places and rapidly changing conditions.

  19. Chemical analysis of polar stratospheric cloud particles

    PubMed

    Schreiner; Voigt; Kohlmann; Arnold; Mauersberger; Larsen

    1999-02-12

    A balloon-borne gondola carrying a particle analysis system, a backscatter sonde, and pressure and temperature sensors was launched from Kiruna, Sweden, on 25 January 1998. Measurements within polar stratospheric cloud layers inside the Arctic polar vortex show a close correlation between large backscatter ratios and enhanced particle-related water and nitric acid signals at low temperatures. Periodic structures in the data indicate the presence of lee waves. The H2O/HNO3 molar ratios are consistently found to be above 10 at atmospheric temperatures between 189 and 192 kelvin. Such high ratios indicate ternary solution particles of H2O, HNO3, and H2SO4 rather than the presence of solid hydrates. PMID:9974386

  20. Arctic spring ozone reduction associated with projected sea ice loss

    NASA Astrophysics Data System (ADS)

    Deser, C.; Sun, L.; Tomas, R. A.; Polvani, L. M.

    2013-12-01

    The impact of Arctic sea ice loss on the stratosphere is investigated using the Whole-Atmosphere Community Climate Model (WACCM), by prescribing the sea ice in the late 20th century and late 21st century, respectively. The localized Sea Surface Temperature (SST) change associated with sea ice melt is also included in the future run. Overall, the model simulates a negative annular-mode response in the winter and spring. In the stratosphere, polar vortex strengthens from February to April, peaking in March. Consistent with it, there is an anomalous cooling in the high-latitude stratosphere, and polar cap ozone reduction is up to 20 DU. Since the difference between these two runs lies only in the sea ice and localized SST in the Arctic, the stratospheric circulation and ozone changes can be attributed to the surface forcing. Eliassen-Palm analysis reveals that the upward propagation of planetary waves is suppressed in the spring as a consequence of sea ice loss. The reduction in propagation causes less wave dissipation and thus less zonal wind deceleration in the extratropical stratosphere.

  1. Decadal Time Scale change in terrestrial plant communities in North American arctic and alpine tundra: A contribution to the International Polar Year Back to the Future Project (Invited)

    NASA Astrophysics Data System (ADS)

    Tweedie, C. E.; Ebert-May, D.; Hollister, R. D.; Johnson, D. R.; Lara, M. J.; Villarreal, S.; Spasojevic, M.; Webber, P.

    2010-12-01

    The International Polar Year-Back to the Future (IPY-BTF) is an endorsed International Polar Year project (IPY project #214). The overarching goal of this program is to determine how key structural and functional characteristics of high latitude/altitude terrestrial ecosystems have changed over the past 25 or more years and assess if such trajectories of change are likely to continue in the future. By rescuing data, revisiting, re-sampling historic research sites and assessing environmental change over time, we aim to provide greater understanding of how tundra is changing and what the possible drivers of these changes are. Resampling of sites established by Patrick J. Webber between 1964 and 1975 in northern Baffin Island, Northern Alaska and in the Rocky Mountains form a key contribution to the BTF project. Here we report on resampling efforts at each of these locations and initial results of a synthesis effort that finds similarities and differences in change between sites. Results suggest that although shifts in plant community composition are detectable at each location, the magnitude and direction of change differ among locations. Vegetation shifts along soil moisture gradients is apparent at most of the sites resampled. Interestingly, however, wet communities seem to have changed more than dry communities in the Arctic locations, while plant communities at the alpine site appear to be becoming more distinct regardless of soil moisture status. Ecosystem function studies performed in conjunction with plant community change suggest that there has been an increase in plant productivity at most sites resampled, especially in wet and mesic land cover types.

  2. Organochlorines in antarctic and arctic avian top predators: a comparison between the South Polar Skua and two species of northern hemisphere gulls.

    PubMed

    Bustnes, Jan O; Tveraa, Torkild; Henden, John A; Varpe, Oystein; Janssen, Kirstin; Skaare, Janneche U

    2006-04-15

    Different organochlorine compounds (OCs) were measured in the blood of breeding south polar skuas (Catharacta maccormicki) at Svarthamaren, Dronning Maud Land (Antarctica) and compared to those in two species of northern hemisphere gulls: the Arctic glaucous gull (Larus hyperboreus) and the subarctic great black-backed gull (Larus marinus). The skuas had 8% and 29% of the SigmaOC levels (45 ng/g, wet weight) of glaucous gulls (591 ng/g) and great black-backed gulls (158 ng/g), respectively. Polychlorinated biphenyls (PCBs) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) were very low in skuas compared to northern gulls, but the mean hexachlorobenzene (HCB) level was 1.7 times higher than in great black-backed gulls and one-third of the glaucous gull level. Mirex levels in skuas were among the highest reported in birds, the mean level being 3 and 26 times higher than those in glaucous gull and great black-backed gulls, respectively. In skuas, the mean levels of HCB, oxychlordane, p,p'-DDE, and PCBs increased by about 30% during a 2-week period, and mirex increased by nearly 60%. In glacuous gulls, HCB, p,p'-DDE, and PCBs increased by 10-20%. For HCB, mirex, and oxychlordane, only a relatively small proportion of the increase in skuas could be explained by changes in lipid pools and the levels at first sampling, compared to glaucous gulls. Thus, skuas were probably accumulating these compounds when present in Antarctica. p,p'-DDE and PCB levels, in contrast, seemed much more stable in the skuas. Relatively high levels of mirex and HCB in south polar skuas are concerning with regard to potential adverse effects. PMID:16683630

  3. Arctic Intersection

    USGS Multimedia Gallery

    The Canadian Coast Guard Ship Louis S. St-Laurent ties up to the Coast Guard Cutter Healy in the Arctic Ocean Sept. 5, 2009. The two ships are taking part in a multi-year, multi-agency Arctic survey that will help define the Arctic continental shelf....

  4. Evidence for subsidence in the 1989 Arctic winter stratosphere from airborne infrared composition measurements

    NASA Technical Reports Server (NTRS)

    Toon, G. C.; Farmer, C. B.; Schaper, P. W.; Lowes, L. L.; Norton, R. H.; Schoeberl, M. R.; Lait, L. R.; Newman, P. A.

    1992-01-01

    Simultaneous measurements of the stratospheric burdens of CO2, HCN, N2O, CH4, OCS, CF2Cl2, CFCl3, CHF2Cl and HF were made by the Jet propulsion Laboratory MkIV interferometer on board the NASA DC-8 aircraft during January and early February 1989 as part of the Airborne Arctic Stratosphere Experiment. Data were acquired on 11 flights at altitudes of up to 12 km over a geographic region covering the NE Atlantic Ocean, Iceland and Greenland. The results obtained show large variations in the burdens of these tracers due to the effects of transport. The tropospheric source gas burdens were reduced inside the polar vortex, suggesting that the air had subsided with respect to the surrounding midlatitude air. Increased HF burdens inside the vortex support this interpretation. The results obtained from the different tracers are highly consistent with each other and indicate that in the 15- to 20-km altitude range inside the vortex, surfaces of constant volume mixing ratio were located some 5-6 km lower in absolute altitude than outside the vortex. The results also indicate that the magnitude of this subsidence increases with altitude. These conclusions are consistent with other measurements.

  5. Vortex dynamics during blade-vortex interactions

    NASA Astrophysics Data System (ADS)

    Peng, Di; Gregory, James W.

    2015-05-01

    Vortex dynamics during parallel blade-vortex interactions (BVIs) were investigated in a subsonic wind tunnel using particle image velocimetry (PIV). Vortices were generated by applying a rapid pitch-up motion to an airfoil through a pneumatic system, and the subsequent interactions with a downstream, unloaded target airfoil were studied. The blade-vortex interactions may be classified into three categories in terms of vortex behavior: close interaction, very close interaction, and collision. For each type of interaction, the vortex trajectory and strength variation were obtained from phase-averaged PIV data. The PIV results revealed the mechanisms of vortex decay and the effects of several key parameters on vortex dynamics, including separation distance (h/c), Reynolds number, and vortex sense. Generally, BVI has two main stages: interaction between vortex and leading edge (vortex-LE interaction) and interaction between vortex and boundary layer (vortex-BL interaction). Vortex-LE interaction, with its small separation distance, is dominated by inviscid decay of vortex strength due to pressure gradients near the leading edge. Therefore, the decay rate is determined by separation distance and vortex strength, but it is relatively insensitive to Reynolds number. Vortex-LE interaction will become a viscous-type interaction if there is enough separation distance. Vortex-BL interaction is inherently dominated by viscous effects, so the decay rate is dependent on Reynolds number. Vortex sense also has great impact on vortex-BL interaction because it changes the velocity field and shear stress near the surface.

  6. Building Partnerships in Polar Research and Education. Report from the Arctic Science Education Workshop (New Orleans, Louisiana, April 6-8, 1997).

    ERIC Educational Resources Information Center

    Arctic Research Consortium of the United States, Fairbanks, AK.

    To examine the role of arctic science in U.S. primary and secondary education, 58 teachers, researchers, and curriculum specialists met in a workshop in April 1997 in New Orleans. The workshop sought to provide a forum for development of K-12 educational materials investigating the Arctic and to bring current research activities into K-12…

  7. Air-water exchange of anthropogenic and natural organohalogens on International Polar Year (IPY) expeditions in the Canadian Arctic.

    PubMed

    Wong, Fiona; Jantunen, Liisa M; Pu?ko, Monika; Papakyriakou, Tim; Staebler, Ralf M; Stern, Gary A; Bidleman, Terry F

    2011-02-01

    Shipboard measurements of organohalogen compounds in air and surface seawater were conducted in the Canadian Arctic in 2007-2008. Study areas included the Labrador Sea, Hudson Bay, and the southern Beaufort Sea. High volume air samples were collected at deck level (6 m), while low volume samples were taken at 1 and 15 m above the water or ice surface. Water samples were taken within 7 m. Water concentration ranges (pg L(-1)) were as follows: ?-hexachlorocyclohexane (?-HCH) 465-1013, ?-HCH 150-254, hexachlorobenzene (HCB) 4.0-6.4, 2,4-dibromoanisole (DBA) 8.5-38, and 2,4,6-tribromoanisole (TBA) 4.7-163. Air concentration ranges (pg m(-3)) were as follows: ?-HCH 7.5-48, ?-HCH 2.1-7.7, HCB 48-71, DBA 4.8-25, and TBA 6.4 - 39. Fugacity gradients predicted net deposition of HCB in all areas, while exchange directions varied for the other chemicals by season and locations. Net evasion of ?-HCH from Hudson Bay and the Beaufort Sea during open water conditions was shown by air concentrations that averaged 14% higher at 1 m than 15 m. No significant difference between the two heights was found over ice cover. The ?-HCH in air over the Beaufort Sea was racemic in winter (mean enantiomer fraction, EF = 0.504 ± 0.008) and nonracemic in late spring-early summer (mean EF = 0.476 ± 0.010). This decrease in EF was accompanied by a rise in air concentrations due to volatilization of nonracemic ?-HCH from surface water (EF = 0.457 ± 0.019). Fluxes of chemicals during the southern Beaufort Sea open water season (i.e., Leg 9) were estimated using the Whitman two-film model, where volatilization fluxes are positive and deposition fluxes are negative. The means ± SD (and ranges) of net fluxes (ng m(-2) d(-1)) were as follows: ?-HCH 6.8 ± 3.2 (2.7-13), ?-HCH 0.76 ± 0.40 (0.26-1.4), HCB -9.6 ± 2.7 (-6.1 to -15), DBA 1.2 ± 0.69 (0.04-2.0), and TBA 0.46 ± 1.1 ng m(-2) d(-1) (-1.6 to 2.0). PMID:21194218

  8. Vortex formation and instability in the left ventricle

    NASA Astrophysics Data System (ADS)

    Le, Trung Bao; Sotiropoulos, Fotis; Coffey, Dane; Keefe, Daniel

    2012-09-01

    We study the formation of the mitral vortex ring during early diastolic filling in a patient-specific left ventricle (LV) using direct numerical simulation. The geometry of the left ventricle is reconstructed from Magnetic Resonance Imaging (MRI) data of a healthy human subject. The left ventricular kinematics is modeled via a cell-based activation methodology, which is inspired by cardiac electro-physiology and yields physiologic LV wall motion. In the fluid dynamics videos, we describe in detail the three-dimensional structure of the mitral vortex ring, which is formed during early diastolic filling. The ring starts to deform as it propagates toward the apex of the heart and becomes inclined. The trailing secondary vortex tubes are formed as the result of interaction between the vortex ring and the LV wall. These vortex tubes wrap around the circumference and begin to interact with and destabilize the mitral vortex ring. At the end of diastole, the vortex ring impinges on the LV wall and the large-scale intraventricular flow rotates in clockwise direction. We show for the first time that the mitral vortex ring evolution is dominated by a number of vortex-vortex and vortex-wall interactions, including lateral straining and deformation of vortex ring, the interaction of two vortex tubes with unequal strengths, helicity polarization of vortex tubes and twisting instabilities of the vortex cores.

  9. The Airborne Arctic Stratospheric Expedition - Prologue

    NASA Technical Reports Server (NTRS)

    Turco, Richard; Plumb, Alan; Condon, Estelle

    1990-01-01

    This paper presents an introduction to the initial scientific results of the Airborne Arctic Stratospheric Expedition (AASE), as well as data from other atmospheric experiments and analyses carried out during the Arctic polar winter of 1989. Mission objectives of the AASE were to study the mechanisms of ozone depletion and redistribution in the northern polar stratosphere, including the influences of Arctic meteorology, and polar stratospheric clouds formed at low temperatures. Some major aspects of the AASE are described including: logistics and operations, meteorology, polar stratospheric clouds, trace composition and chemistry, and ozone depletion. It is concluded that the Arctic-89 experiments have provided the scientific community with a wealth of new information that will contribute to a better understanding of the polar winter stratosphere and the critical problem of global ozone depletion.

  10. ATMOS Measurements of H2O + 2CH4 and Total Reactive Nitrogen in the November 1994 Antarctic Stratosphere: Dehydration and Denitrification in the Vortex

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Gunson, M. R.; Salawitch, R. J.; Newchurch, M. J.; Zander, R.; Abbas, M. M.; Abrams, M. C.; Manney, G. L.; Michelsen, H. A.; Chang, A. Y.; Goldman, A.

    1996-01-01

    Simultaneous stratospheric volume mixing ratios (VMR's) measured inside and outside the Antarctic vortex by the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument in November 1994 reveal previously unobserved features in the distributions of total reactive nitrogen (NO(y)) and total hydrogen (H2O + 2CH4). Maximum removal of NO(y) due to sedimentation of polar stratospheric clouds (PSC's) inside the vortex occurred at a potential temperature (Theta) of 500-525 K (approximately 20 km), where values were 5 times smaller than measurements outside. Maximum loss of H2O + 2CH4 due to PSC's occurred in the vortex at 425-450 K, approximately 3 km lower than the peak NO(y) loss. At that level, H2O + 2CH4 VMR's inside the vortex were approximately 70% of corresponding values outside. The Antarctic and April 1993 Arctic measurements by ATMOS show no significant differences in H2O + 2CH4 VMR's outside the vortices in the two hemispheres. Elevated NO(y) VMRs were measured inside the vortex near 700 K. Recent model calculations indicate that this feature results from downward transport of elevated NO(y) produced in the thermosphere and mesosphere.

  11. Arctic stratospheric ice nucleation and dehydration within CLaMS

    NASA Astrophysics Data System (ADS)

    Tritscher, Ines; Grooß, Jens-Uwe; Müller, Rolf

    2015-04-01

    Polar stratospheric clouds (PSCs) provide the surface for heterogeneous reactions enhancing concentrations of active, ozone destroying chlorine and thereby cause polar ozone loss in late winter and early spring. The understanding of PSC microphysics is therefore essential to simulate polar ozone accurately. The Chemical Lagrangian Model of the Stratosphere (CLaMS) allows growth, evaporation, and gravitational settling of individual cloud particles to be calculated along their trajectories. Particles consisting of nitric acid trihydrate (NAT) were the focus of previous work and are known for their potential to denitrify the polar stratosphere by sedimentation. This study goes a step further and deals with the nucleation of ice particles and related dehydration, i.e. irreversible redistribution of water vapor. Homogeneous and heterogeneous nucleation of ice particles have been considered. Finally, we will also include NAT formation downwind of ice clouds. To start with, we concentrate on the Arctic winter 2009/2010, which is already well characterized because of the RECONCILE campaign and connected work. Unusually low temperatures at stratospheric levels led to the formation of synoptic-scale ice PSCs for a week-long period. We present CLaMS results in comparison to PSC observations from the cloud-aerosol lidar CALIOP. Moreover, we juxtapose CLaMS simulations of water vapor with single balloon-borne measurements as well as with vortex-wide MLS observations. The hemispheric picture allows tracking dehydrated air masses around the vortex. Changes in the denitrification pattern, which might arise due to the implementation of ice particles, will be discussed.

  12. Measurements of total reactive nitrogen during the Airborne Arctic Stratospheric Expedition

    NASA Technical Reports Server (NTRS)

    Kawa, S. R.; Fahey, D. W.; Anderson, L. C.; Loewenstein, M.; Chan, K. R.

    1990-01-01

    Composite distributions of measured total reactive nitrogen NO(y), from the NASA ER-2 during the Airborne Arctic Stratospheric Expedition are presented. The observed features of these distributions are discussed in terms of the controlling dynamical, chemical and microphysical processes. In the latitudinal profile from 58 deg N to within about 4 deg poleward of the polar vortex boundary, NO(y) conforms closely to predictions of NO(y) based on N2O measurements. Poleward of 5 deg of latitude within the boundary, the average NO(y) decreases sharply and is significantly lower than that predicted from N2O. This feature is consistent with loss of NO(y) through sedimentation of particles containing NO(y) in polar stratospheric clouds.

  13. Stratospheric Aerosol Measurement II (SAM II) aerosol measurements during the 1989 AASE (Airborne Arctic Stratospheric Expedition)

    SciTech Connect

    Osborn, M.T.; Pitts, M.C.; Powell, K.A. ); McCormick, M.P. )

    1990-03-01

    The Stratospheric Aerosol Measurement II (SAM II) satellite experiment measures 14 daily 1.0-{mu}m aerosol extinction profiles in the high northern latitudes. These SAM II data were used to spot the locations of polar stratospheric clouds (PSCs) and provide an overview of the vertical structure of the upper tropospheric and stratospheric aerosols during the 1989 Airborne Arctic Stratospheric Expedition (AASE). Contour plots of aerosol extinction vs. longitude and altitude are shown for 24 days during AASE which summarize these measurements. PSC sightings occurred during the first week of January and from January 18 through February 2, 1989. Although SAM II measured a higher than average number of PSCs in January 1989 as compared to the previous 10 years, the number of PSCs sighted during the entire 1989 winter season is only slightly above average. Also discussed is the vertical gradient in aerosol extinction which occurs as the SAM II measurement locations cross the polar vortex.

  14. Polar low monitoring

    NASA Astrophysics Data System (ADS)

    Bobylev, Leonid; Zabolotskikh, Elizaveta; Mitnik, Leonid

    2010-05-01

    Polar lows are intense mesoscale atmospheric low pressure weather systems, developing poleward of the main baroclinic zone and associated with high surface wind speeds. Small size and short lifetime, sparse in-situ observations in the regions of their development complicate polar low study. Our knowledge of polar lows and mesocyclones has come almost entirely during the period of satellite remote sensing since, by virtue of their small horizontal scale, it was rarely possible to analyse these lows on conventional weather charts using only the data from the synoptic observing network. However, the effects of intense polar lows have been felt by coastal communities and seafarers since the earliest times. These weather systems are thought to be responsible for the loss of many small vessels over the centuries, although the nature of the storms was not understood and their arrival could not be predicted. The actuality of the polar low research is stipulated by their high destructive power: they are a threat to such businesses as oil and gas exploration, fisheries and shipping. They could worsen because of global warming: a shrinking of sea ice around the North Pole, which thawed to its record minimum in the summer of 2007, is likely to give rise to more powerful storms that form only over open water and can cause hurricane-strength winds. Therefore, study of polar lows, their timely detection, tracking and forecasting represents a challenge for today meteorology. Satellite passive microwave data, starting from Special Sensor Microwave Imager (SSM/I) onboard Defense Meteorological Satellite Program (DMSP) satellite, remain invaluable source of regularly available remotely sensed data to study polar lows. The sounding in this spectral range has several advantages in comparison with observations in visible and infrared ranges and Synthetic Aperture Radar (SAR) data: independence on day time and clouds, regularity and high temporal resolution in Polar Regions. Satellite passive microwave data make it possible to retrieve several important atmospheric and oceanic parameters inside the polar lows, such as sea surface wind speed, water vapour content in the atmosphere, total liquid water content in the clouds and others, providing not only qualitative image of a vortex, but also quantitative information about these severe events, constituting a promising tool for their study and monitoring. An approach for detection and tracking of polar lows is developed utilizing the data from two sensors: SSM/I onboard DMSP and Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) onboard Aqua satellite. This approach consists of two stages. At the first stage total atmospheric water vapor fields are retrieved from SSM/I and AMSRE-E measurement data using precise Arctic polar algorithms, developed at NIERSC. These algorithms are applicable over open water. They have high retrieval accuracies under a wide range of environmental conditions. Algorithms are based on numerical simulation of brightness temperatures and their inversion by means of Neural Networks. At the second stage the vortex structures are detected in these fields, polar lows are identified and tracked and some of their parameters are calculated. A few case studies are comprehensively conducted based on SSM/I and AMSRE-E measurements and using other satellite data including visible, infrared and SAR images, QuickScat Scatterometer wind fields, surface analysis maps and re-analysis data, which demonstrated the advantages of satellite passive microwave data usage in the polar low studies.

  15. Simulating Arctic Climate Warmth and Icefield Retreat in the

    E-print Network

    Born, Andreas

    , Devon, and Meighen ice caps in the Canadian Arctic, and possibly in Camp Century (northwest Greenland the entire western Arctic from 57-N to 85-N, including Greenland and smaller scale ice caps in Iceland Project members In the future, Arctic warming and the melting of polar glaciers will be considerable

  16. Marine Transportation Implications of the Last Arctic Sea Ice Refuge

    NASA Astrophysics Data System (ADS)

    Brigham, L. W.

    2010-12-01

    Marine access is increasing throughout the Arctic Ocean and the 'Last Arctic Sea Ice Refuge' may have implications for governance and marine use in the region. Arctic marine transportation is increasing due to natural resource developemnt, increasing Arctic marine tourism, expanded Arctic marine research, and a general linkage of the Arctic to the gloabl economy. The Arctic Council recognized these changes with the release of the Arctic Marine Shipping Assessment of 2009. This key study (AMSA)can be viewed as a baseline assessment (using the 2004 AMSA database), a strategic guide for a host of stakeholders and actors, and as a policy document of the Arctic Council. The outcomes of AMSA of direct relevance to the Ice Refuge are within AMSA's 17 recommendations provided under three themes: Enhancing Arctic Marine Safety, Protecting Arctic People and the Environment, and Building the Arctic Marine Infrastructure. Selected recommendations of importance to the Ice Refuge include: a mandatory polar navigation code; identifying areas of heightened ecological and cultural significance; potential designation of special Arctic marine areas; enhancing the tracking and monitoring of Arctic marine traffic; improving circumpolar environmental response capacity; developing an Arctic search and rescue agreement; and, assessing the effects of marine transportation on marine mammals. A review will be made of the AMSA outcomes and how they can influence the governance, marine use, and future protection of this unique Arctic marine environment.

  17. A New Ground-Based Carbon Monoxide Radiometer for Observing the Dynamics of the Arctic Middle Atmosphere

    NASA Astrophysics Data System (ADS)

    Ryan, Niall; Palm, Mathias; Notholt, Justus

    2015-04-01

    The dynamical properties of the middle atmosphere must largely be derived from interpretation of observed chemical tracer data, predominantly from measurements by ground-based or satellite-borne instruments. Carbon monoxide (CO) is a well-suited tracer for polar middle atmosphere dynamics: during polar winter, the chemical reactions involving the gas are negligible due to lack of sunlight and the gas exhibits strong vertical and horizontal gradients. Ground-based measurements of the atmosphere are increasingly important for making long-term records of atmospheric composition and, because of the likely upcoming gap in satellite measurements, are needed to intercompare past and future satellite instruments. This contribution presents a new ground-based millimeter wave radiometer, CORAM, that is designed to measure radiation, at ~230 GHz, emitted during rotational transitions of CO. CORAM will be housed at the APIWEV station in Ny Alesund, Spitsbergen (79° N), an ideal location for observing middle atmosphere dynamics from inside and outside the polar vortex, and make continuous CO observations in the High-Arctic. The observations from CORAM will be used for validation of the polar dynamics in atmospheric models, and to investigate the short-term variability of polar middle atmosphere dynamics. Used in combination with measurements in Kiruna, Sweden (68° N), information about the CO gradient across the polar vortex edge can also be recovered. I will describe the new instrument and inversion technique, and present the ability of the observation system operating in a High-Arctic location. I will show the sensitivity of the system to CO concentrations in the altitude range of approximately 40-80 km with a preliminary error analysis using optimal estimation, and the effect of inversion nonlinearities on CO trend analysis.

  18. Vortex methods

    SciTech Connect

    Chorin, A.J. |

    1993-06-01

    Vortex methods originated from the observation that in incompressible inviscid flow vorticity (or, more accurately, circulation) is a conserved quantity, as can be readily deduced from the absence of tangential stresses. Thus, if the vorticity is known at time t=0, one can find the flow at a later time by simply following the vorticity. In this narrow context, a vortex method is a numerical method that follows vorticity. The author restricts himself in these lectures to a special class of numerical vortex methods, those that are based on a Lagrangian transport of vorticity in hydrodynamics by smoothed particles (blobs) and those whose analysis contributes to the understanding of blob methods. Blob methods started in the 1930`s.

  19. Interhemispheric differences in polar stratospheric HNO{sub 3}, H{sub 2}O, ClO, and O{sub 3}

    SciTech Connect

    Santee, M.L.; Read, W.G.; Waters, J.W.; Froidevaux, L.; Manney, G.L.; Flower, D.A.; Jarnot, R.F.; Harwood, R.S.

    1995-02-10

    Simultaneous global measurements of nitric acid (HNO{sub 3}), water (H{sub 2}O), chlorine monoxide (ClO), and ozone (O{sub 3}) in the stratosphere have been obtained over complete annual cycles in both hemispheres by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite. A sizeable decrease in gas-phase HNO{sub 3} was evident in the lower stratospheric vortex over Antarctica by early June 1992, followed by a significant reduction in gas-phase H{sub 2}O after mid-July. By mid-August, near the time of peak ClO, abundances of gas-phase HNO{sub 3} and H{sub 2}O were extremely low. The concentrations of HNO{sub 3} and H{sub 2}O over Antarctica remained depressed into November, well after temperatures in the lower stratosphere had risen above the evaporation threshold for polar stratospheric clouds, implying that denitrification and dehydration had occurred. No large decreases in either gas-phase HNO{sub 3} or H{sub 2}O were observed in the 1992-1993 Arctic winter vortex. Although ClO was enhanced over the Arctic as it was over the Antarctic, Arctic O{sub 3} depletion was substantially smaller than that over Antarctica. A major factor currently limiting the formation of an Arctic ozone {open_quotes}hole{close_quotes} is the lack of denitrification in the northern polar vortex, but future cooling of the lower stratosphere could lead to more intense denitrification and consequently larger losses of Arctic ozone. 34 refs., 2 figs.

  20. Super Interglacials and persistent warmth paced Arctic Climate Evolution over the Past 3.6 Myr: Lake El'gygytgyn, Western Beringia, a new polar lens focused on high latitude environmental change

    NASA Astrophysics Data System (ADS)

    Brigham-Grette, Julie; Melles, Martin; Minyuk, Pavel

    2013-04-01

    The Pliocene-Pleistocene climate evolution of the Arctic must have modulated the glacial history of Greenland and the onset of Northern Hemisphere glaciation. Yet what is known from the terrestrial stratigraphy of Arctic climate change comes from sites that are spatially and temporally fragmented. In 2009, International Continental Deep drilling at Lake El'gygytgyn (67o30' N, 172 o 05' E) recovered lacustrine sediments dating back to 3.58 Ma that now provide the first time-continuous Pliocene-Pleistocene Arctic paleoclimate record of alternating glacial-interglacial change. The warmest/wettest Pliocene interval of the lake record occurs from ~3.58-3.34 Ma and is dominated by exceptional tree pollen implying July temperatures nearly 7-8o C warmer than today with nearly ~3 times the annual precipitation. Atmospheric CO2 levels are estimated to have been 360 to 400 ppm implying exceptionally high climate sensitivity and polar amplification. In fact, pollen spectra and modern analog analysis show an unbroken persistence of summers much warmer and wetter than the last interglacial, MIS 5e until nearly 2.2 Ma. Extreme warmth in the Mid Pliocene Arctic occurs at the same time ANDRILL results suggest the West Antarctic Ice Sheet was non-existent. Modeling sensitivity experiments using 300 and 400 ppm CO2 are consistent with sustained forests at Lake El'gygytgyn during this interval and restricted glacial ice over Greenland in both cold and warm boreal summer orbits especially for the PRISM interval. This has implications for reinterpreting the M2 isotopic shift in the North Atlantic suggesting that most of the ice advance at that time was in Antarctica. Using physical, chemical, and biological proxies we find pronounced glacial episodes commenced ~2.6 Ma ago, but the full range of typical Pleistocene glacial/interglacial change wasn't established until ~1.8 Ma ago. Greenland must have also responded to numerous "super interglacials" during the Quaternary record, with maximum summer temperatures and annual precipitation, especially during MIS 9,11 and 31, at Lake El'gygytgyn exceeding that documented for MIS 5e. The correspondence of many of these super-interglacials with retreat of the West Antarctic Ice Sheet (Naish et al. 2009) could coincide with intervals when the Greenland Ice was reduced in size. The climate record from Lake El'gygytgyn, especially the history of past interglacials, provides a fresh means of testing the evolving magnitude of polar amplification over time, and the sensitivity of the Greenland Ice Sheet to extreme warmth in the rest of the Arctic.

  1. Is There an Arctic Ozone Hole?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.

    1999-01-01

    Total ozone observations from the Total Ozone Mapping Spectrometer (TOMS) instruments during March 1997 revealed an extensive region of low column densities in the Arctic region centered near the north pole. Values were below 250 Dobson units for nearly a two week period during this period, and were correlated with the position of the northern lower stratospheric polar vortex. The March 1997 average total ozone column densities were more than 30% lower than the average of column densities observed during the 1979-1982 March period. Both the northern spring seasons of 1998 and 1999 have shown much higher levels of total ozone. In this presentation, we will discuss the causes of the low total ozone values in 1997 and contrast those low values with the higher 1998 and 1999 observations. The reason for my travel to the University of Valparaiso is to give this seminar and provide information to my colleagues on our work here at GSFC. The benefit to NASA is to interact with my Univ. of Valparaiso colleagues, gain their insights and input into this research, and establish collaborations with the current research efforts at the University.

  2. Dietary correlates of an at-risk BMI among Inuit adults in the Canadian high arctic: cross-sectional international polar year Inuit health survey, 2007-2008

    PubMed Central

    2012-01-01

    Background The study’s objective was to investigate the dietary correlates of an at-risk body mass index (BMI) among Inuit adults from thirty-six communities across the Canadian Arctic using data from the cross-sectional International Polar Year Inuit Health Survey, conducted in 2007–2008. Methods The survey included assessments of 24-hr dietary recall, sociodemographics, physical activity, and anthropometry. Dietary characteristics of overweight and obesity were similar and therefore combined into one at- risk BMI category (?25?kg/m2) for analyses. The relationship between an at-risk BMI and energy intake from macronutrients, high sugar drinks, high-fat foods, saturated fatty acids, and traditional foods were examined entering each dietary variable separately into a logistic regression model as an independent variable. Analyses were adjusted for age, sex, region, kcalories, walking, smoking and alcohol consumption. Further multivariable models considered selected dietary variables together in one model. Results An at-risk BMI was present for 64% with a prevalence of overweight and obesity of 28% and 36%, respectively. Consumption of high-sugar drinks (>15.5% E) was significantly related with having an at-risk BMI (OR?=?1.6; 95% CI 1.2; 2.2), whereas the % E from total carbohydrate evaluated as a continuous variable and as quartiles was inversely related to an at-risk BMI (P?-trend

  3. Public Perceptions of Arctic Change

    NASA Astrophysics Data System (ADS)

    Hamilton, L.

    2014-12-01

    What does the general US public know, or think they know, about Arctic change? Two broad nationwide surveys in 2006 and 2010 addressed this topic in general terms, before and after the International Polar Year (IPY). Since then a series of representative national or statewide surveys have carried this research farther. The new surveys employ specific questions that assess public knowledge of basic Arctic facts, along with perceptions about the possible consequences of future Arctic change. Majorities know that late-summer Arctic sea ice area has declined compared with 30 years ago, although substantial minorities -- lately increasing -- believe instead that it has now recovered to historical levels. Majorities also believe that, if the Arctic warms in the future, this will have major effects on the weather where they live. Their expectation of local impacts from far-away changes suggests a degree of global thinking. On the other hand, most respondents do poorly when asked whether melting Arctic sea ice, melting Greenland/Antarctic land ice, or melting Himalayan glaciers could have more effect on sea level. Only 30% knew or guessed the right answer to this question. Similarly, only 33% answered correctly on a simple geography quiz: whether the North Pole could best be described as ice a few feet or yards thick floating over a deep ocean, ice more than a mile thick over land, or a rocky, mountainous landscape. Close analysis of response patterns suggests that people often construct Arctic "knowledge" on items such as sea ice increase/decrease from their more general ideology or worldview, such as their belief (or doubt) that anthropogenic climate change is real. When ideology or worldviews provide no guidance, as on the North Pole or sealevel questions, the proportion of accurate answers is no better than chance. These results show at least casual public awareness and interest in Arctic change, unfortunately not well grounded in knowledge. Knowledge problems seen on these surveys highlights both the need and the challenge of communicating polar science.

  4. Investigation of elliptical vortex beams propagating in atmospheric turbulence by numerical simulations

    NASA Astrophysics Data System (ADS)

    Taozheng

    2015-08-01

    In recent years, due to the high stability and privacy of vortex beam, the optical vortex became the hot spot in research of atmospheric optical transmission .We numerically investigate the propagation of vector elliptical vortex beams in turbulent atmosphere. Numerical simulations are realized with random phase screen. To simulate the vortex beam transport processes in the atmospheric turbulence. Using numerical simulation method to study in the atmospheric turbulence vortex beam transmission characteristics (light intensity, phase, polarization, etc.) Our simulation results show that, vortex beam in the atmospheric transmission distortion is small, make elliptic vortex beam for space communications is a promising strategy.

  5. Record-breaking Ozone Loss during Arctic Winter 2010/2011: Comparison with Arctic Winter 1996/1997

    NASA Astrophysics Data System (ADS)

    Godin Beekmann, S.; Kuttipurath, J.; Lefèvre, F.; Santee, M. L.; Froidevaux, L.

    2011-12-01

    Polar processing and chemical ozone loss is analysed during the Arctic winter/spring 2010/2011. The analyses with temperatures and potential vorticity (PV) data show a prolonged vortex from early December through mid-April. The PV maps illustrate strong vortex persistence in the lower stratosphere between 450 and 675 K, showing similar evolution with time. The minimum temperatures extracted from ECMWF data at 40-90°N show values below 195 K for a record period of first week of December through second week of April, indicating the longest period of colder temperatures for 17 years. At 10 hPa, there was a warming of about 10 K at 60°N and 40 K at 90°N around mid-January. The heat flux also showed high values in line with the increase in temperatures, of about 425 m K/s at 60°N at the same pressure level. However, the westerlies were strong (e.g. 35-45 m/s at 60°N) enough to keep the vortex intact until mid-April. Because of the cold temperatures in late winter and early spring, large areas of Polar Stratospheric Clouds (PSC) were found in the 400-600 K isentropic level range. Though the maximum values of PSCs area are smaller compared to other cold winters such as 2005, the extended period of presence of PSCs during this winter was exceptional, especially in late February-mid-March, in agreement with the cold temperatures during the period. Ozone loss analyses with high resolution Mimosa-Chim chemical transport model simulations show that the loss started by early January, and was about 0.5 ppmv in late January. The loss progressed slowly to 1 ppmv by the end of February, and then intensified by early March. The ozone depletion estimated by the passive method finds a maximum value of about 2-2.3 ppmv by the end of March-early April in the 450-550K range inside the vortex, which coincides with the areas of PSCs and high chlorine activation. This is the largest loss ever estimated with this model for any Arctic winter. It is consistent with the unprecedented chlorine activation that occurred in the winter, as the modeled ClO values show about 1.7 ppbv in early January and about 1 ppbv in March at 450-550K. This is longest period of chlorine activation noted among the Arctic winters. The ozone partial column loss reaches about 115-150 DU in the range 350 - 550 K. These model results for ozone, ozone loss and ClO are in good agreement with those found from Aura Microwave Limb Sounder observations. Since the winter 1996/1997 was also very cold in March - April, a comparison between both winters 2011 and 1997 will be presented, based on temperature, PV, Heat flux data and ozone loss estimations. Similarities and differences in the polar processing and ozone loss during both winters will be discussed using various measurements and model simulations. Copyright 2011. All rights reserved.

  6. Arctic Watch

    NASA Astrophysics Data System (ADS)

    Orcutt, John; Baggeroer, Arthur; Mikhalevsky, Peter; Munk, Walter; Sagen, Hanne; Vernon, Frank; Worcester, Peter

    2015-04-01

    The dramatic reduction of sea ice in the Arctic Ocean will increase human activities in the coming years. This will be driven by increased demand for energy and the marine resources of an Arctic Ocean more accessible to ships. Oil and gas exploration, fisheries, mineral extraction, marine transportation, research and development, tourism and search and rescue will increase the pressure on the vulnerable Arctic environment. Synoptic in-situ year-round observational technologies are needed to monitor and forecast changes in the Arctic atmosphere-ice-ocean system at daily, seasonal, annual and decadal scales to inform and enable sustainable development and enforcement of international Arctic agreements and treaties, while protecting this critical environment. This paper will discuss multipurpose acoustic networks, including subsea cable components, in the Arctic. These networks provide communication, power, underwater and under-ice navigation, passive monitoring of ambient sound (ice, seismic, biologic and anthropogenic), and acoustic remote sensing (tomography and thermometry), supporting and complementing data collection from platforms, moorings and autonomous vehicles. This paper supports the development and implementation of regional to basin-wide acoustic networks as an integral component of a multidisciplinary, in situ Arctic Ocean Observatory.

  7. Arctic winter 2010/2011 at the brink of an ozone hole

    NASA Astrophysics Data System (ADS)

    Sinnhuber, B.-M.; Stiller, G.; Ruhnke, R.; von Clarmann, T.; Kellmann, S.; Aschmann, J.

    2011-12-01

    The Arctic stratospheric winter of 2010/2011 was one of the coldest on record with a large loss of stratospheric ozone. Observations of temperature, ozone, nitric acid, water vapor, nitrous oxide, chlorine nitrate and chlorine monoxide from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard ENVISAT are compared to calculations with a chemical transport model (CTM). There is overall excellent agreement between the model calculations and MIPAS observations, indicating that the processes of denitrification, chlorine activation and catalytic ozone depletion are sufficiently well represented. Polar vortex integrated ozone loss reaches 120 Dobson Units (DU) by early April 2011. Sensitivity calculations with the CTM give an additional ozone loss of about 25 DU at the end of the winter for a further cooling of the stratosphere by 1 K, showing locally near-complete ozone depletion (remaining ozone <200 ppbv) over a large vertical extent from 16 to 19 km altitude. In the CTM a 1 K cooling approximately counteracts a 10% reduction in stratospheric halogen loading, a halogen reduction that is expected to occur in about 13 years from now. These results indicate that severe ozone depletion like in 2010/2011 or even worse could appear for cold Arctic winters over the next decades if the observed tendency for cold Arctic winters to become colder continues into the future.

  8. Airborne Arctic Stratospheric Expedition 2: An overview

    NASA Technical Reports Server (NTRS)

    Anderson, James G.; Toon, Owen B.

    1993-01-01

    The sudden onset of ozone depletion in the antarctic vortex set a precedent for both the time scale and the severity of global change. The Airborne Antarctic Ozone Experiment (AAOE), stages from Punta Arenas, Chile, in 1987, established that CFCs, halons, and methyl bromide, the dominant sources of chlorine and bromide radicals in the stratosphere, control the rate of ozone destruction over the Antarctic; that the vortex is depleted in reactive nitrogen and water vapor; and that diabatic cooling during the antarctic winter leads to subsidence within the vortex core, importing air from higher altitudes and lower latitudes. This last conclusion is based on observed dramatic distortion in the tracer fields, most notably N2O. In 1989, the first Airborne Arctic Stratospheric Expedition (AASE-1), staged from Stavanger, Norway, and using the same aircraft employed for AAOE (the NASA ER-2 and the NASA DC-8), discovered that while NO(x) and to some degree NO(y) were perturbed within the arctic vortex, there was little evidence for desiccation. Under these (in contrast to the antarctic) marginally perturbed conditions, however, ClO was found to be dramatically enhanced such that a large fraction of the available (inorganic) chlorine resided in the form of ClO and its dimer ClOOCl. This leaves two abiding issues for the northern hemisphere and the mission of the second Airborne Arctic Stratospheric Expedition (AASE-2): (1) Will significant ozone erosion occur within the arctic vortex in the next ten years as chlorine loading in the stratosphere exceeds four parts per billion by volume? (2) Which mechanisms are responsible for the observed ozone erosion poleward of 30 deg N in the winter/spring northern hemisphere reported in satellite observations?

  9. Airborne Arctic Stratospheric Expedition 2: An Overview

    NASA Technical Reports Server (NTRS)

    Anderson, James G.; Toon, Owen B.

    1993-01-01

    The sudden onset of ozone depletion in the antarctic vortex set a precedent for both the time scale and the severity of global change. The Airborne Antarctic Ozone Experiment (AAOE), staged from Punta Arenas, Chile, in 1987, established that CFCs, halons, and methyl bromide, the dominant sources of chlorine and bromine radicals in the stratosphere, control the rate of ozone destruction over the Antarctic; that the vortex is depleted in reactive nitrogen and water vapor; and that diabatic cooling during the antarctic winter leads to subsidence within the vortex core, importing air from higher altitudes and lower latitudes. This last conclusion is based on observed dramatic distortion in the tracer fields, most notably N2O. In 1989, the first Airborne Arctic Stratospheric Expedition (AASE-I), staged from Stavanger, Norway, and using the same aircraft employed for AAOE (the NASA ER-2 and the NASA DC-8), discovered that while NO(x) and to some degree NO(y) were perturbed within the arctic vortex, there was little evidence for desiccation. Under these (in contrast to the antarctic) marginally perturbed conditions, however, Cl0 was found to be dramatically enhanced such that a large fraction of the available (inorganic) chlorine resided in the form of Cl0 and its dimer ClOOCl. This leaves two abiding issues for the northern hemisphere and the mission of the second Airborne Arctic Stratospheric Expedition (AASE-II): (1) Will significant ozone erosion occur within the arctic vortex in the next ten years as chlorine loading in the stratosphere exceeds four parts per billion by volume? and (2) Which mechanisms are responsible for the observed ozone erosion poleward of 30 deg N in the winter/spring northern hemisphere reported in satellite observations?

  10. Dynamics of recent climate change in the Arctic.

    PubMed

    Moritz, Richard E; Bitz, Cecilia M; Steig, Eric J

    2002-08-30

    The pattern of recent surface warming observed in the Arctic exhibits both polar amplification and a strong relation with trends in the Arctic Oscillation mode of atmospheric circulation. Paleoclimate analyses indicate that Arctic surface temperatures were higher during the 20th century than during the preceding few centuries and that polar amplification is a common feature of the past. Paleoclimate evidence for Holocene variations in the Arctic Oscillation is mixed. Current understanding of physical mechanisms controlling atmospheric dynamics suggests that anthropogenic influences could have forced the recent trend in the Arctic Oscillation, but simulations with global climate models do not agree. In most simulations, the trend in the Arctic Oscillation is much weaker than observed. In addition, the simulated warming tends to be largest in autumn over the Arctic Ocean, whereas observed warming appears to be largest in winter and spring over the continents. PMID:12202816

  11. Arctic house

    E-print Network

    Turkel, Joel A. (Joel Abram), 1969-

    1999-01-01

    Currently available housing in the Arctic is limited to solutions that have been adapted from designs for less severe climates. This thesis has developed a new manner of residential construction designed specifically for ...

  12. Arctic Refuge

    Atmospheric Science Data Center

    2014-05-15

    ... and is the largest wildlife refuge in the United States. Animals of the Refuge include the 130,000-member Porcupine caribou herd, 180 ... location:  United States Arctic Ocean region:  Alaska and Hawaii Order:  27 ...

  13. On the seasonal onset of polar mesospheric clouds and the breakdown of

    E-print Network

    Wirosoetisno, Djoko

    On the seasonal onset of polar mesospheric clouds and the breakdown of the stratospheric polar) On the seasonal onset of polar mesospheric clouds and the breakdown of the stratospheric polar vortex the seasonal onset of polar mesospheric clouds and the breakdown of the stratospheric polar vortex

  14. Arctic energy technologies workshop: proceedings

    SciTech Connect

    Not Available

    1985-04-01

    The objectives of this ''Arctic Energy Technologies Workshop'' were threefold: To acquaint participants with the current US Department of Energy, Office of Fossil Energy, Arctic and Offshore Research Program. To obtain information on Arctic oil and gas development problem areas, and on current and planned research. To provide an opportunity for technical information exchange among engineers, geologists, geophysicists, physical scientists, oceanographers, statisticians, analysts, and other participants engaged in similar research areas. The first section of the proceedings is the keynote address ''Current Arctic Offshore Technology'', presented by Kenneth Croasdale, of K.R. Croasdale and Associates, Ltd., Calgary, Alberta, Canada. The second section of the proceedings includes 14 technical papers presented in two sessions at the Workshop: Sea Ice Research, and Seafloor/Soils Research. The third section of the proceedings includes the summaries of four work-group discussion sessions from the second day of the meeting: (1) Arctic Offshore Structures, (2) Arctic Offshore Pipelines, (3) Subice Development Systems, and (4) Polar-Capable Ice Vessels. The work groups addressed state-of-the-art, technical issues, R and D needs, and environmental concerns in these four areas. All papers in this proceedings have been processed for inclusion in the Energy Data Base.

  15. Simulation of polar ozone depletion: An update

    NASA Astrophysics Data System (ADS)

    Solomon, Susan; Kinnison, Doug; Bandoro, Justin; Garcia, Rolando

    2015-08-01

    We evaluate polar ozone depletion chemistry using the specified dynamics version of the Whole Atmosphere Community Climate Model for the year 2011. We find that total ozone depletion in both hemispheres is dependent on cold temperatures (below 192 K) and associated heterogeneous chemistry on polar stratospheric cloud particles. Reactions limited to warmer temperatures above 192 K, or on binary liquid aerosols, yield little modeled polar ozone depletion in either hemisphere. An imposed factor of three enhancement in stratospheric sulfate increases ozone loss by up to 20 Dobson unit (DU) in the Antarctic and 15 DU in the Arctic in this model. Such enhanced sulfate loads are similar to those observed following recent relatively small volcanic eruptions since 2005 and imply impacts on the search for polar ozone recovery. Ozone losses are strongly sensitive to temperature, with a test case cooler by 2 K producing as much as 30 DU additional ozone loss in the Antarctic and 40 DU in the Arctic. A new finding of this paper is the use of the temporal behavior and variability of ClONO2 and HCl as indicators of the efficacy of heterogeneous chemistry. Transport of ClONO2 from the southern subpolar regions near 55-65°S to higher latitudes near 65-75°S provides a flux of NOx from more sunlit latitudes to the edge of the vortex and is important for ozone loss in this model. Comparisons between modeled and observed total column and profile ozone perturbations, ClONO2 abundances, and the rate of change of HCl bolster confidence in these conclusions.

  16. In situ measurements of the ClO/HCl ratio: Heterogeneous processing on sulfate aerosols and polar stratospheric clouds

    NASA Technical Reports Server (NTRS)

    Webster, C. R.; May, R. D.; Toohey, D. W.; Avallone, L. M.; Anderson, J. G.; Solomon, S.

    1993-01-01

    Simultaneous in situ measurements of stratospheric ClO and HCl have been made for the first time, during numerous flights of the ER-2 aircraft covering latitudes 24-90 deg N from October 1991 through March 1992. The ClO/HCl ratio is identified as a key indicator of heterogeneous processing both outside and within the Arctic polar vortex. For ClO mixing ratios below about 120 pptv, remarkably constant ClO/HCl values of about 15% characterize the lower stratosphere. The observed values are significantly higher than those derived from a 2-D model using either gas phase photochemistry alone (2%), or including heterogeneous sulfate chemistry (5-10%). During the Arctic early spring, after conversion of HCl into reactive chlorine has taken place, the vortex edge is poorly defined by ClO levels. Loss of HCl and its slow recovery following low-temperature polar heterogeneous chemistry distinguishes HCl as a new and unique dynamical tracer of polar stratospheric clouds (PSC)-processed air.

  17. Aerosols and polar stratospheric clouds measurements during the EASOE campaign

    NASA Technical Reports Server (NTRS)

    Haner, D.; Godin, S.; Megie, G.; David, C.; Mitev, V.

    1992-01-01

    Preliminary results of observations performed using two different lidar systems during the EASOE (European Arctic Stratospheric Ozone Experiment), which has taken place in the winter of 1991-1992 in the northern hemisphere lattitude regions, are presented. The first system is a ground based multiwavelength lidar intended to perform measurements of the ozone vertical distribution in the 5 km to 40 km altitude range. It was located in Sodankyla (67 degrees N, 27 degrees E) as part of the ELSA experiment. The objectives of the ELSA cooperative project is to study the relation between polar stratospheric cloud events and ozone depletion with high vertical resolution and temporal continuity, and the evolution of the ozone distribution in relation to the position of the polar vortex. The second system is an airborne backscatter lidar (Leandre) which allows for the study of the 3-D structure and the optical properties of polar stratospheric clouds. The Leandre instrument is a dual-polarization lidar system, emitting at 532 nm, which allows for the determination of the type of clouds observed, according to the usual classification of polar stratospheric clouds. More than 60 hours of flight were performed in Dec. 1991, and Jan. and Feb. 1992 in Kiruna, Sweden. The operation of the Leandre instrument has led to the observation of the short scale variability of the Pinatubo volcanic cloud in the high latitude regions and to several episodes of polar stratospheric clouds. Preliminary analysis of the data is presented.

  18. Chemical ozone loss and ozone mini-hole event during the Arctic winter 2010/2011 as observed by SCIAMACHY and GOME-2

    NASA Astrophysics Data System (ADS)

    Hommel, R.; Eichmann, K.-U.; Aschmann, J.; Bramstedt, K.; Weber, M.; von Savigny, C.; Richter, A.; Rozanov, A.; Wittrock, F.; Khosrawi, F.; Bauer, R.; Burrows, J. P.

    2014-04-01

    Record breaking loss of ozone (O3) in the Arctic stratosphere has been reported in winter-spring 2010/2011. We examine in detail the composition and transformations occurring in the Arctic polar vortex using total column and vertical profile data products for O3, bromine oxide (BrO), nitrogen dioxide (NO2), chlorine dioxide (OClO), and polar stratospheric clouds (PSC) retrieved from measurements made by SCIAMACHY (Scanning Imaging Absorption SpectroMeter for Atmospheric CHartography) on-board Envisat (Environmental Satellite), as well as total column ozone amount, retrieved from the measurements of GOME-2 (Global Ozone Monitoring Experiment) on MetOp-A (Meteorological Experimental Satellite). Similarly we use the retrieved data from DOAS (Differential Optical Absorption Spectroscopy) measurements made in Ny-Ålesund (78.55° N, 11.55° E). A chemical transport model (CTM) has been used to relate and compare Arctic winter-spring conditions in 2011 with those in the previous year. In late winter-spring 2010/2011 the chemical ozone loss in the polar vortex derived from SCIAMACHY observations confirms findings reported elsewhere. More than 70% of O3 was depleted by halogen catalytic cycles between the 425 and 525 K isentropic surfaces, i.e. in the altitude range ~16-20 km. In contrast, during the same period in the previous winter 2009/2010, a typical warm Arctic winter, only slightly more than 20% depletion occurred below 20 km, while 40% of O3 was removed above the 575 K isentrope (~23 km). This loss above 575 K is explained by the catalytic destruction by NOx descending from the mesosphere. In both Arctic winters 2009/2010 and 2010/2011, calculated O3 losses from the CTM are in good agreement to our observations and other model studies. The mid-winter 2011 conditions, prior to the catalytic cycles being fully effective, are also investigated. Surprisingly, a significant loss of O3 around 60%, previously not discussed in detail, is observed in mid-January 2011 below 500 K (~19 km) and sustained for approximately 1 week. The low O3 region had an exceptionally large spatial extent. The situation was caused by two independently evolving tropopause elevations over the Asian continent. Induced adiabatic cooling of the stratosphere favoured the formation of PSC, increased the amount of active chlorine for a short time, and potentially contributed to higher polar ozone loss later in spring.

  19. An Assessment of the Ozone Loss During the 1999-2000 SOLVE Arctic Campaign

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.; Newman, Paul A.; Lait, Leslie R.; McGee, Thomas J.; Burris, John F.; Browell, Edward V.; Grant, William B.; Richard, Eric; VonderGathen, Peter; Bevilacqua, Richard; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Ozone observations from ozonesondes, the lidars aboard the DC-8, in situ ozone measurements from the ER-2, and satellite ozone measurements from Polar Ozone and Aerosol Measurement III (POAM) were used to assess ozone loss during the Sage III Ozone Loss and Validation Experiment (SOLVE) 1999-2000 Arctic campaign. Two methods of analysis were used. In the first method a simple regression analysis is performed on the ozonesonde and POAM measurements within the vortex. In the second method, the ozone measurements from all available ozone data were injected into a free running diabatic trajectory model and carried forward in time from December 1 to March 15. Vortex ozone loss was then estimated by comparing the ozone values of those parcels initiated early in the campaign with those parcels injected later in the campaign. Despite the variety of observational techniques used during SOLVE, the measurements provide a fairly consistent picture. Over the whole vortex, the largest ozone loss occurs between 550 and 400 K potential temperatures (approximately 23-16 km) with over 1.5 ppmv lost by March 15, the end of the SOLVE mission period. An ozone loss rate of 0.04-0.05 ppmv/day was computed for March 15. Ozonesondes launched after March 15 suggest that an additional 0.5 ppmv or more ozone was lost between March 15 and April 1. The small disagreement between ozonesonde and POAM analysis of January ozone loss is found to be due to biases in vortex sampling. POAM makes most of its solar occultation measurements at the vortex edge during January 2000 which bias samples toward air parcels that have been exposed to sunlight and likely do experience ozone loss. Ozonesonde measurements and the trajectory technique use observations that are more distributed within the interior of the vortex. Thus the regression analysis of the POAM measurements tends to overestimate mid-winter vortex ozone loss. Finally, our loss calculations are broadly consistent with other loss computations using ER-2 tracer data and MLS satellite data, but we find no evidence for the 1992 high mid-January loss reported using the Match technique.

  20. NO2 vertical profiles retrieved from ground-based measurements during spring 1999 in the Canadian Arctic

    E-print Network

    Strong, Kimberly

    10 K warmer than those over Antarctica, pre- venting the formation of polar stratospheric clouds; Canadian Arctic; Arctic polar vertex 1. Introduction The dramatic springtime stratospheric ozone (O3 2003; accepted 4 August 2003 Abstract During the 1990s, Arctic stratospheric temperatures were lower

  1. Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere

    NASA Technical Reports Server (NTRS)

    Allen, D. R.; Douglass, A. R.; Manney, G. L.; Strahan, S. E.; Krosschell, J. C.; Trueblood, J.

    2010-01-01

    Immediately following the breakup of the 2005 Arctic spring stratospheric vortex, a tropical air mass, characterized by low potential vorticity (PV) and high nitrous oxide (N2O), was advected poleward and became trapped in the easterly summer polar vortex. This feature, known as a "Frozen-In Anticyclone (FrIAC)", was observed in Earth Observing System (EOS) Aura Microwave Limb Sounder (MLS) data to span the potential temperature range from approximately 580 to 1100 K (approximately 25 to 40 km altitude) and to persist from late March to late August 2005. This study compares MLS N2O observations with simulations from the Global Modeling Initiative (GMI) chemistry and transport model, the GEOS-5/MERRA Replay model, and the VanLeer Icosahedral Triangular Advection isentropic transport model to elucidate the processes involved in the lifecycle of the FrIAC which is here divided into three distinct phases. During the "spin-up phase" (March to early April), strong poleward flow resulted in a tight isolated anticyclonic vortex at approximately 70-90 deg N, marked with elevated N2O. GMI, Replay, and VITA all reliably simulted the spin-up of the FrIAC, although the GMI and Replay peak N2O values were too low. The FrIAC became trapped in the developing summer easterly flow and circulated around the polar region during the "anticyclonic phase" (early April to the end of May). During this phase, the FrIAC crossed directly over the pole between the 7th and 14th of April. The VITA and Replay simulations transported the N2O anomaly intact during this crossing, in agreement with MLS, but unrealistic dispersion of the anomaly occurred in the GMI simulation due to excessive numerical mixing of the polar cap. The vortex associated with the FrIAC was apparently resistant to the weak vertical hear during the anticyclonic phase, and it thereby protected the embedded N20 anomaly from stretching. The vortex decayed in late May due to diabatic processes, leaving the N2O anomaly exposed to horizontal and vertical wind shears during the "shearing phase" (June to August). The observed lifetime of the FrIAC during this phase is consistent with time-scales calculated from the ambient horizontal and vertical wind shear. Replay maintained the horizontal structure of the N2O anomaly similar to NILS well into August. The VITA simulation also captured the horizontal structure of the FrIAC during this phase, but VITA eventually developed fine-scale N2O structure not observed in MLS data.

  2. Study Of The Fundamental Physical Principles in Atmospheric Modeling Based On Identification Of Atmosphere - Climate Control Factors: Bromine Explosion At The Polar Arctic Sunrise

    E-print Network

    M. Iudin

    2010-07-09

    We attempt is to provide accumulated evidence and qualitative understanding of the associated atmospheric phenomena of the Arctic bromine explosion and their role in the functioning of the biotic Earth. We rationalize the empirical expression of the bromine influx into atmospheric boundary layer and calculate total amounts of the tropospheric BrO and Bry of the Arctic origin. Based on the quantities and partitioning of the reactive bromine species, we estimate the biogeochemical parametric constraint on the surface ozone field of the springtime NH. The constraint expresses strong relationship between atmosphere-climate control factors of the Earth's life and of external energy source. Physical atmosphere can be seen as a complex network of maximum complexity. Henceforth, we analyze the network context of the Arctic bromine pollution. We suggest that demonstrated attitudinal approach to the distributed surface flux would be successfully used in the innovative atmospheric modeling. The analysis is illustrated by GEM model results which stay in a good agreement with the observational data and support the original idea of the global NH effect of bromine chemistry.

  3. Unprecedented Arctic ozone loss in 2011.

    PubMed

    Manney, Gloria L; Santee, Michelle L; Rex, Markus; Livesey, Nathaniel J; Pitts, Michael C; Veefkind, Pepijn; Nash, Eric R; Wohltmann, Ingo; Lehmann, Ralph; Froidevaux, Lucien; Poole, Lamont R; Schoeberl, Mark R; Haffner, David P; Davies, Jonathan; Dorokhov, Valery; Gernandt, Hartwig; Johnson, Bryan; Kivi, Rigel; Kyrö, Esko; Larsen, Niels; Levelt, Pieternel F; Makshtas, Alexander; McElroy, C Thomas; Nakajima, Hideaki; Parrondo, Maria Concepción; Tarasick, David W; von der Gathen, Peter; Walker, Kaley A; Zinoviev, Nikita S

    2011-10-27

    Chemical ozone destruction occurs over both polar regions in local winter-spring. In the Antarctic, essentially complete removal of lower-stratospheric ozone currently results in an ozone hole every year, whereas in the Arctic, ozone loss is highly variable and has until now been much more limited. Here we demonstrate that chemical ozone destruction over the Arctic in early 2011 was--for the first time in the observational record--comparable to that in the Antarctic ozone hole. Unusually long-lasting cold conditions in the Arctic lower stratosphere led to persistent enhancement in ozone-destroying forms of chlorine and to unprecedented ozone loss, which exceeded 80 per cent over 18-20 kilometres altitude. Our results show that Arctic ozone holes are possible even with temperatures much milder than those in the Antarctic. We cannot at present predict when such severe Arctic ozone depletion may be matched or exceeded. PMID:21964337

  4. Method of stabilizing flueric vortex valves and vortex amplifiers

    NASA Technical Reports Server (NTRS)

    Erwin, L. R.; Mc Fall, R. H.

    1970-01-01

    Inducing losses in the vortex chamber of vortex valves and vortex amplifiers resolves the problem of unstable operation caused by a sufficiently large positive feedback. Induced losses also reduce pressure gain and throttling range of vortex pressure amplifier.

  5. Vortex Flow Aerodynamics, volume 1

    NASA Technical Reports Server (NTRS)

    Campbell, J. F. (editor); Osborn, R. F. (editor); Foughner, J. T., Jr. (editor)

    1986-01-01

    Vortex modeling techniques and experimental studies of research configurations utilizing vortex flows are discussed. Also discussed are vortex flap investigations using generic and airplane research models and vortex flap theoretical analysis and design studies.

  6. Polar Science Is Cool!

    ERIC Educational Resources Information Center

    Weeks, Sophie

    2012-01-01

    Children are fascinated by the fact that polar scientists do research in extremely cold and dangerous places. In the Arctic they might be viewed as lunch by a polar bear. In the Antarctic, they could lose toes and fingers to frostbite and the wind is so fast it can rip skin off. They camp on ice in continuous daylight, weeks from any form of…

  7. Climatology of large-scale isentropic mixing in the Arctic winter stratosphere from analyzed winds

    NASA Technical Reports Server (NTRS)

    Dahlberg, Steven P.; Bowman, Kenneth P.

    1994-01-01

    Dynamic isolation of the winter Arctic circumpolar vortex is studied using analyzed winds derived from geopotential height fields. Isentropic trajectories are calculated for assemblages of particles initialized on uniform latitude-longitude grids. Transport across isolines of Ertel potential vorticity (PV) is used to characterize the mixing processes of ejection of vortex air and entrainment of midlatitude air into the vortex. During January and February a barrier to mixing, where exchange of air is inhibited, typically forms near the vortex boundary. At 450 K, transport across the barrier is predominantly in the form of thin filaments of particles ejected from the vortex. These filaments tend to wrap around the vortex, creating a layered structure of vortex and midlatitude air at the vortex edge. Near or total splits of the vortex into two or more distinct vortex fragments are quite common based on these trajectory calculations. Significant entrainment deep into the vortex is rare and results from only a limited number of the splitting events. During December and March the mixing barrier is less evident due to nonconservative factors during the spin-up and breakdown of the vortex, respectively. In December both ejection and entrainment are only weakly inhibited by the mixing barrier. Exchange in March is dominated by ejection of air from the vortex.

  8. Ozone and other trace gases in the Arctic and Antarctic regions: Three-dimensional model simulations

    SciTech Connect

    Granier, C.; Brasseur, G. )

    1991-02-20

    A three-dimensional mechanistic model of the middle atmosphere with calculated dynamics and chemistry is used to study the behavior of chemically active trace gases at high latitudes in winter and spring, and to simulate the formation of an ozone hole in Antarctica. The dynamics of both hemispheres is simulated by applying at the lower boundary of the model (8.5 km) a wavelike perturbation representing qualitatively a climatological tropospheric forcing. The chemical heterogeneous processes converting chlorine reservoirs into active chlorine in cold air masses are parameterized. The model simulates the behavior of nitrogen oxides, nitric acid, water vapor, methane, hydrogen radicals, chlorine compounds, and ozone. It reproduces important features observed during different Antarctic and Arctic observation campaigns. The ozone hole in the southern hemisphere can only be simulated when the heterogeneous polar chemistry is taken into account. The springtime ozone depletion over Antarctica calculated in the model is thus mostly the result of chemical removal although the dynamics is responsible for the low temperature that triggers the large ozone loss rates. Unresolved questions are related to the strength of the vertical exchanges inside the vortex, the preconditioning of trace gases before and during the winter season, the behavior of the different trace gases as the vortex breaks down (dilution effects), accurate determination of the ozone sink inside the vortex, and a better quantitative estimation of the role of polar stratospheric clouds. Despite elevated concentrations of active chlorine at high latitudes in the northern hemisphere in late winter, no ozone hole is produced by the model, even with chlorine levels as high as 6 ppbv. This conclusion could, however, be modified for very stable and cold winters with delayed final warming.

  9. Microphysical Simulations of Polar Stratospheric Clouds Compared with Calipso and MLS Observations

    NASA Astrophysics Data System (ADS)

    Zhu, Y.; Toon, O. B.; Kinnison, D. E.; Lambert, A.; Brakebusch, M.

    2014-12-01

    Polar stratospheric clouds (PSCs) form in the lower stratosphere during the polar night due to the cold temperature inside the polar vortex. PSCs are important to understand because they are responsible for the formation of the Antarctic ozone hole and the ozone depletion over the Arctic. In this work, we explore the formation and evolution of STS particles (Super-cooled Ternary Solution) and NAT (Nitric-acid Trihydrate) particles using the SD-WACCM/CARMA model. SD-WACCM/CARMA couples the Whole Atmosphere Community Climate Model using Specific Dynamics with the microphysics model (CARMA). The 2010-2011 Arctic winter has been simulated because the Arctic vortex remained cold enough for PSCs from December until the end of March (Manney et al., 2011). The unusual length of this cold period and the presence of PSCs caused strong ozone depletion. This model simulates the growth and evaporation of the STS particles instead of considering them as being in equilibrium as other models do (Carslaw et al., 1995). This work also explores the homogeneous nucleation of NAT particles and derives a scheme for NAT formation based on the observed denitrification during the winter 2010-2011. The simulated microphysical features (particle volumes, size distributions, etc.) of both STS (Supercooled Ternary Solutions) and NAT particles show a consistent comparison with historical observations. The modeled evolution of PSCs and gas phase ozone related chemicals inside the vortex such as HCl and ClONO2 are compared with the observations from MLS, MIPAS and CALIPSO over this winter. The denitrification history indicate the surface nucleation rate from Tabazadeh et al. (2002) removes too much HNO3 over the winter. With a small modification of the free energy term of the equation, the denitification and the PSC backscattering features are much closer to the observations. H2O, HCl, O3 and ClONO2 are very close to MLS and MIPAS observations inside the vortex. The model underestimates ozone depletion for this winter by about 15%.

  10. Episodes of Cross-Polar Transport in the Arctic Troposphere During July 2008 as Seen from Models, Satellite, and Aircraft Observations

    NASA Technical Reports Server (NTRS)

    Sodemann, H.; Pommier, M.; Arnold, S. R.; Monks, S. A.; Stebel, K.; Burkhart, J. F.; Hair, J. W.; Diskin, G. S.; Clerbaux, C.; Coheur, P.-F.; Hurtmans, D.; Schlager, H.; Blechschmidt, A.-M.; Kristjansson, J. E.; Stohl, A.

    2011-01-01

    During the POLARCAT summer campaign in 2008, two episodes (2 5 July and 7 10 July 2008) occurred where low-pressure systems traveled from Siberia across the Arctic Ocean towards the North Pole. The two cyclones had extensive smoke plumes from Siberian forest fires and anthropogenic sources in East Asia embedded in their associated air masses, creating an excellent opportunity to use satellite and aircraft observations to validate the performance of atmospheric transport models in the Arctic, which is a challenging model domain due to numerical and other complications. Here we compare transport simulations of carbon monoxide (CO) from the Lagrangian transport model FLEXPART and the Eulerian chemical transport model TOMCAT with retrievals of total column CO from the IASI passive infrared sensor onboard the MetOp-A satellite. The main aspect of the comparison is how realistic horizontal and vertical structures are represented in the model simulations. Analysis of CALIPSO lidar curtains and in situ aircraft measurements provide further independent reference points to assess how reliable the model simulations are and what the main limitations are. The horizontal structure of mid-latitude pollution plumes agrees well between the IASI total column CO and the model simulations. However, finer-scale structures are too quickly diffused in the Eulerian model. Applying the IASI averaging kernels to the model data is essential for a meaningful comparison. Using aircraft data as a reference suggests that the satellite data are biased high, while TOMCAT is biased low. FLEXPART fits the aircraft data rather well, but due to added background concentrations the simulation is not independent from observations. The multi-data, multi-model approach allows separating the influences of meteorological fields, model realisation, and grid type on the plume structure. In addition to the very good agreement between simulated and observed total column CO fields, the results also highlight the difficulty to identify a data set that most realistically represents the actual pollution state of the Arctic atmosphere.

  11. Current induced vortex wall dynamics in helical magnetic systems

    NASA Astrophysics Data System (ADS)

    Roostaei, Bahman

    2015-03-01

    Nontrivial topology of interfaces separating phases with opposite chirality in helical magnetic metals result in new effects as they interact with spin polarized current. These interfaces or vortex walls consist of a one dimensional array of vortex lines. We predict that adiabatic transfer of angular momentum between vortex array and spin polarized current will result in topological Hall effect in multi-domain samples. Also we predict that the motion of the vortex array will result in a new damping mechanism for magnetic moments based on Lenz's law. We study the dynamics of these walls interacting with electric current and use fundamental electromagnetic laws to quantify those predictions. On the other hand discrete nature of vortex walls affects their pinning and results in low depinning current density. We predict the value of this current using collective pinning theory.

  12. Proceedings of the eighth international conference on offshore mechanics and Arctic engineering. 1989

    SciTech Connect

    Sinha, N.K. ); Sodhi, D.S. ); Chung, J.S. )

    1989-01-01

    This book contains papers presented at a conference on arctic and polar technology. The topics covered are: Ice properties; Ice mechanics and dynamics; Spray ice technology; Ice forces; Ice accretion; Standards on arctic developments; The Barents Sea; and Arctic structures and drilling.

  13. Peeking through a frosty window: molecular insights into the ecology of Arctic soil fungi

    E-print Network

    Taylor, Lee

    Peeking through a frosty window: molecular insights into the ecology of Arctic soil fungi Ina: Arctic Biodiversity Climate change Cold adaptation Community structure Edaphic factors Fungi Mycorrhiza Polar regions Stress tolerance Tundra a b s t r a c t Fungi are ubiquitous in Arctic soils, where

  14. A Remotely Operated Lidar for Aerosol, Temperature, and Water Vapor Profiling in the High Arctic

    E-print Network

    Duck, Thomas J.

    facilitate year-round study of the polar atmosphere. Disproportionate climatic change in the Arctic has in the changing Arctic climate than the albedo. Knowledge of the vertical dis- tribution of the water vapor Arctic (798599N, 858569W) as part of the Canadian Network for the Detection of Atmospheric Change

  15. Ocean advection, Arctic-Atlantic Connections, Climate P.B.Rhines, University of Washington

    E-print Network

    Ocean advection, Arctic-Atlantic Connections, Climate P.B.Rhines, University of Washington Sirpa to high Arctic · Atmospheric and oceanic transports, strongly coupled, supply continental and polar warmth scales of atmospheric circulation, · Transports by ocean circulation: connecting the Arctic and Atlantic

  16. The Arctic Research Consortium of the United States (ARCUS)

    NASA Astrophysics Data System (ADS)

    Fox, S. E.; Wiggins, H. V.

    2011-12-01

    The Arctic Research Consortium of the United States (ARCUS) is a nonprofit membership organization composed of universities and institutions that have a substantial commitment to research in the Arctic. ARCUS was formed in 1988 to serve as a forum for planning, facilitating, coordinating, and implementing interdisciplinary studies of the Arctic; to act as a synthesizer and disseminator of scientific information on arctic research; and to educate scientists and the general public about the needs and opportunities for research in the Arctic. ARCUS, in collaboration with the broader science community, relevant agencies and organizations, and other stakeholders, coordinates science planning and educational activities across disciplinary and organizational boundaries. Examples of ARCUS projects include: - Arctic Sea Ice Outlook - an international effort that provides monthly summer reports synthesizing community estimates of the expected sea ice minimum. - Sea Ice for Walrus Outlook - a resource for Alaska Native subsistence hunters, coastal communities, and others that provides weekly reports with information on sea ice conditions relevant to walrus in Alaska waters. - PolarTREC (Teachers and Researchers Exploring and Collaborating) - a program whereby K-12 educators and researchers work together in hands-on field experiences in the Arctic and Antarctic to advance polar science education. - ArcticInfo mailing list, Witness the Arctic newsletter, and the Arctic Calendar - communication tools for the arctic science community to keep apprised of relevant news, meetings, and announcements. - Coordination for the Study of Environmental Arctic Change (SEARCH) program, which aims to provide scientific understanding of arctic environmental change to help society understand and respond to a rapidly changing Arctic.

  17. The Arctic Research Consortium of the United States (ARCUS)

    NASA Astrophysics Data System (ADS)

    Fox, S. E.; Wiggins, H. V.; Creek, K. R.

    2012-12-01

    The Arctic Research Consortium of the United States (ARCUS) is a nonprofit membership organization composed of universities and institutions that have a substantial commitment to research in the Arctic. Founded in 1988 to serve as a forum for advancing interdisciplinary studies of the Arctic, ARCUS synthesizes and disseminates scientific information on arctic research and educates scientists and the general public about the needs and opportunities for research in the Arctic. ARCUS works closely with national and international stakeholders in advancing science planning and educational activities across disciplinary and organizational boundaries. Examples of ARCUS projects include: - Arctic Sea Ice Outlook - an international effort that provides monthly summer reports synthesizing community estimates of the expected sea ice minimum. - Sea Ice for Walrus Outlook - a resource for Alaska Native subsistence hunters, coastal communities, and others that provides weekly reports with information on sea ice conditions relevant to walrus in Alaska waters. - PolarTREC (Teachers and Researchers Exploring and Collaborating) - a program for K-12 educators and researchers to work together in hands-on field experiences in the Arctic and Antarctic to advance polar science education. - ArcticInfo mailing list, Witness the Arctic newsletter, and the Arctic Calendar - communication tools for the arctic community to keep apprised of relevant news, meetings, and announcements. - Project Office for the Study of Environmental Arctic Change (SEARCH) program, which aims to provide scientific understanding of arctic environmental change to help society understand and respond to a rapidly changing Arctic. More information about these and other ARCUS activities can be found at the ARCUS website at: http://www.arcus.org.

  18. The Arctic Research Consortium of the United States (ARCUS)

    NASA Astrophysics Data System (ADS)

    Creek, K. R.; Fox, S. E.

    2013-12-01

    The Arctic Research Consortium of the United States (ARCUS) is a nonprofit membership organization composed of universities and institutions that have a substantial commitment to research in the Arctic. Founded in 1988 to serve as a forum for advancing interdisciplinary studies of the Arctic, ARCUS synthesizes and disseminates scientific information on arctic research and educates scientists and the general public about the needs and opportunities for research in the Arctic. ARCUS works closely with national and international stakeholders in advancing science planning and educational activities across disciplinary and organizational boundaries. Examples of ARCUS projects include: - Arctic Sea Ice Outlook - an international effort that provides monthly summer reports synthesizing community estimates of the expected sea ice minimum. - Sea Ice for Walrus Outlook - a resource for Alaska Native subsistence hunters, coastal communities, and others that provides weekly reports with information on sea ice conditions relevant to walrus in Alaska waters. - PolarTREC (Teachers and Researchers Exploring and Collaborating) - a program for K-12 educators and researchers to work together in hands-on field experiences in the Arctic and Antarctic to advance polar science education. - ArcticInfo mailing list, Witness the Arctic newsletter, and the Arctic Calendar - communication tools for the arctic community to keep apprised of relevant news, meetings, and announcements. - Project Office for the Study of Environmental Arctic Change (SEARCH) program, which aims to provide scientific understanding of arctic environmental change to help society understand and respond to a rapidly changing Arctic. More information about these and other ARCUS activities can be found at the ARCUS website at: http://www.arcus.org.

  19. Quality of reanalysis data during stratospheric vortex weakening and intensification events

    E-print Network

    Son, Seok-Woo

    winter, stratospheric polar vortex often abruptly changes within a week or two, resulting in a sudden warming or cooling in the polar stratosphere. Such extreme events, which are often referredQuality of reanalysis data during stratospheric vortex weakening and intensification events Patrick

  20. Lesson Summary Students will learn about the Arctic Beaufort Sea

    E-print Network

    Mojzsis, Stephen J.

    of people and animals in the arctic regions. They will also learn about how their actions can affect - Get an Animal's-Eye View - Preserving Biodiversity Polar Regions: Arctic Adaptations and Global Impacts Overview: Ocean literacy involves understanding, among other things, that the ocean supports

  1. Fractional vortex Hilbert's Hotel

    E-print Network

    Gbur, Greg

    2015-01-01

    We demonstrate how the unusual mathematics of transfinite numbers, in particular a nearly perfect realization of Hilbert's famous hotel paradox, manifests in the propagation of light through fractional vortex plates. It is shown how a fractional vortex plate can be used, in principle, to create any number of "open rooms," i.e. topological charges, simultaneously. Fractional vortex plates are therefore demonstrated to create a singularity of topological charge, in which the vortex state is completely undefined and in fact arbitrary.

  2. Comparisons of polar processing diagnostics from 34 years of the ERA-Interim and MERRA reanalyses

    NASA Astrophysics Data System (ADS)

    Lawrence, Z. D.; Manney, G. L.; Minschwaner, K.; Santee, M. L.; Lambert, A.

    2015-04-01

    We present a comprehensive comparison of polar processing diagnostics derived from the National Aeronautics and Space Administration (NASA) Modern Era Retrospective-analysis for Research and Applications (MERRA) and the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Reanalysis (ERA-Interim). We use diagnostics that focus on meteorological conditions related to stratospheric chemical ozone loss based on temperatures, polar vortex dynamics, and air parcel trajectories to evaluate the effects these reanalyses might have on polar processing studies. Our results show that the agreement between MERRA and ERA-Interim changes significantly over the 34 years from 1979 to 2013 in both hemispheres and in many cases improves. By comparing our diagnostics during five time periods when an increasing number of higher-quality observations were brought into these reanalyses, we show how changes in the data assimilation systems (DAS) of MERRA and ERA-Interim affected their meteorological data. Many of our stratospheric temperature diagnostics show a convergence toward significantly better agreement, in both hemispheres, after 2001 when Aqua and GOES (Geostationary Operational Environmental Satellite) radiances were introduced into the DAS. Other diagnostics, such as the winter mean volume of air with temperatures below polar stratospheric cloud formation thresholds (VPSC) and some diagnostics of polar vortex size and strength, do not show improved agreement between the two reanalyses in recent years when data inputs into the DAS were more comprehensive. The polar processing diagnostics calculated from MERRA and ERA-Interim agree much better than those calculated from earlier reanalysis data sets. We still, however, see fairly large differences in many of the diagnostics in years prior to 2002, raising the possibility that the choice of one reanalysis over another could significantly influence the results of polar processing studies. After 2002, we see overall good agreement among the diagnostics, which demonstrates that the ERA-Interim and MERRA reanalyses are equally appropriate choices for polar processing studies of recent Arctic and Antarctic winters.

  3. Comparisons of polar processing diagnostics from 34 years of the ERA-Interim and MERRA reanalyses

    NASA Astrophysics Data System (ADS)

    Lawrence, Z. D.; Manney, G. L.; Minschwaner, K.; Santee, M. L.; Lambert, A.

    2014-12-01

    We present a comprehensive comparison of polar processing diagnostics derived from the National Aeronautics and Space Administration (NASA) Modern Era Retrospective-analysis for Research and Applications (MERRA) and the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Reanalysis (ERA-Interim). We use diagnostics that focus on meteorological conditions related to stratospheric chemical ozone loss based on temperatures, polar vortex dynamics, and air parcel trajectories to evaluate the effects these reanalyses might have on polar processing studies. Our results show that the agreement between MERRA and ERA-Interim changes significantly over the 34 years from 1979 through 2013 in both hemispheres, and in many cases improves. By comparing our diagnostics during five time periods when an increasing number of higher quality observations were brought into these reanalyses, we show how changes in the data assimilation systems (DAS) of MERRA and ERA-Interim affected their meteorological data. Many of our stratospheric temperature diagnostics show a convergence toward significantly better agreement, in both hemispheres, after 2001 when Aqua and GOES (Geostationary Operational Environmental Satellite) radiances were introduced into the DAS. Other diagnostics, such as the winter mean volume of air with temperatures below polar stratospheric cloud formation thresholds (VPSC) and some diagnostics of polar vortex size and strength, do not show improved agreement between the two reanalyses in recent years when data inputs into the DAS were more comprehensive. The polar processing diagnostics calculated from MERRA and ERA-Interim agree much better than those calculated from earlier reanalysis datasets. We still, however, see fairly large relative biases in many of the diagnostics in years prior to 2002, raising the possibility that the choice of one reanalysis over another could significantly influence the results of polar processing studies. After 2002, we see overall good agreement among the diagnostics, which demonstrates that the ERA-Interim and MERRA reanalyses are equally appropriate choices for polar processing studies of recent Arctic and Antarctic winters.

  4. In Situ Measurements of the ClO/HCl Ratio: Heterogeneous Processing on Sulfate Aerosols and Polar Stratospheric Clouds

    NASA Technical Reports Server (NTRS)

    Webster, C. R.; May, R. D.; Toohey, D. W.; Avallone, L. M.; Anderson, J. G.; Solomon, S.

    1993-01-01

    Simultaneous in situ measurements of stratospheric ClO and HCl have been made for the first time, during numerous flights of the ER-2 aircraft covering latitudes 24-90 deg. N from October 1991 through March 1992. The ClO/HCl ratio is identified as a key indicator of heterogeneous processing both outside and within the Arctic polar vortex. For ClO mixing ratios below about 120 pptv, remarkably constant ClO/HCl values of about 15% characterize the lower stratosphere. The observed values are significantly higher than those derived from a 2-D model using either gas phase photochemistry alone (2%), or including heterogeneous sulfate chemistry (5-10%). During the Arctic early spring, after conversion of HCl into reactive chlorine has taken place, the vortex edge is poorly defined by ClO levels. Loss of HCl and its slow recovery following low-temperature polar heterogeneous chemistry distinguishes HCl as a new and unique dynamical tracer of PSC-processed air.

  5. In Situ Measurements of the ClO/HCl Ratio: Heterogeneous Processing on Sulfate Aerosols and Polar Stratospheric Clouds

    NASA Technical Reports Server (NTRS)

    Webster, C. R.; May, R. D.; Toohey, D. W.; Avallone, L. M.; Anderson, J. G.; Solomon, S.

    1993-01-01

    Simultaneous in situ measurements of stratospheric ClO and HCl have been made for the first time, during numerous flights of the ER-2 aircraft covering latitudes 24-90 deg N from October 1991 through March 1992. The ClO/HCl ratio is identified as a key indicator of heterogeneous processing both outside and within the Arctic polar vortex. For ClO mixing ratios below about 120 pptv, remarkably constant ClO/HCl values of about 15% characterize the lower stratosphere. The observed values are significantly higher than those derived from a 2-D model using either gas phase photochemistry alone (2%), or including heterogeneous sulfate chemistry (5-10%). During the Arctic early spring, after conversion of HCl into reactive chlorine has taken place, the vortex edge is poorly defined by ClO levels. Loss of HCl and its slow recovery following low-temperature polar heterogeneous chemistry distinguishes HCl as a new and unique dynamical tracer of PSC-processed air.

  6. In situ measurements of the ClO/HCl ratio: Heterogeneous processing on sulfate aerosols and polar stratospheric clouds

    SciTech Connect

    Webster, C.R.; May, R.D. ); Toohey, D.W. ); Avallone, L.M.; Anderson, J.G. ); Solomon, S.

    1993-11-19

    Simultaneous in situ measurements of stratospheric ClO and HCl have been made for the first time, during numerous flights of the ER-2 aircraft covering latitudes 24-90[degrees]N from October 1991 through March 1992. The ClO/HCl ratio is identified as a key indicator of heterogeneous processing both outside and within the Arctic polar vortex. For ClO mixing ratios below about 120 pptv, remarkably constant ClO/HCl values of about 15% characterize the lower stratosphere. The observed values are significantly higher than those derived from a 2-D model using either gas phase photochemistry alone (2%), or including heterogeneous sulfate chemistry (5-10%). During the Arctic early spring, after conversion of HCl into reactive chlorine has taken place, the vortex edge is poorly defined by ClO levels. Loss of HCl and its slow recovery following low-temperature polar heterogeneous chemistry distinguishes HCl as a new and unique dynamical tracer of PSC-processed air. 19 refs., 4 figs.

  7. Aura's Microwave Limb Sounder Estimates of Ozone Loss, 2004/2005 Arctic Winter

    NASA Technical Reports Server (NTRS)

    2005-01-01

    These data maps from Aura's Microwave Limb Sounder depict levels of hydrogen chloride (top), chlorine monoxide (center), and ozone (bottom) at an altitude of approximately 19 kilometers (490,000 feet) on selected days during the 2004-05 Arctic winter. White contours demark the boundary of the winter polar vortex.

    The maps from December 23, 2004, illustrate vortex conditions shortly before significant chemical ozone destruction began. By January 23, 2005, chlorine is substantially converted from the 'safe' form of hydrogen chloride, which is depleted throughout the vortex, to the 'unsafe' form of chlorine monoxide, which is enhanced in the portions of the region that receive sunlight at that time of year. Ozone increased over the month as a result of dynamical effects, and chemical ozone destruction is just beginning at this time. A brief period of intense cold a few days later promotes further chlorine activation and consequent changes in hydrogen chloride and chlorine monoxide levels on January 27, 2005. Peak chlorine monoxide enhancement occurs in early February.

    By February 24, 2005, chlorine deactivation is well underway, with chlorine monoxide abundances dropping and hydrogen chloride abundances rising. Almost all chlorine monoxide has been quenched by March 10, 2005. The fact that hydrogen chloride has not fully rebounded to December abundances suggests that some of that chemical was recovered into another chlorine reservoir species.

    Ozone maps for January 27, 2005, through March 10, 2005, show indications of mixing of air from outside the polar vortex into it. Such occurrences throughout this winter, especially in late February and early March, complicate analyses, and detailed calculations are required to rigorously disentangle chemical and dynamical effects and accurately diagnose chemical ozone destruction.

    Based on various analyses of Microwave Limb Sounder data, we estimate that maximum local ozone loss of approximately 2 parts per million by volume (approximately 60 percent) has taken place at this level during the period from January 23, 2005, to March 10, 2005, with vortex-averaged loss of approximately 1.5 parts per million by volume.

  8. Vortex profiles and vortex interactions at the electroweak crossover

    NASA Astrophysics Data System (ADS)

    Chernodub, M. N.; Ilgenfritz, E.-M.; Schiller, A.

    Local correlations of Z-vortex operators with gauge and Higgs fields (lattice quantum vortex profiles) as well as vortex two-point functions are studied in the crossover region near a Higgs mass of 100 GeV within the 3 DSU(2) Higgs model. The vortex profiles resemble certain features of the classical vortex solutions in the continuum. The vortex-vortex interactions are analogous to the interactions of Abrikosov vortices in a type-I superconductor.

  9. Satellite-derived attributes of cloud vortex systems and their application to climate studies

    NASA Technical Reports Server (NTRS)

    Carleton, Andrew M.

    1987-01-01

    Defense Meteorological Satellite Program (DMSP) visible and infrared mosaics are analyzed in conjunction with synoptic meteorological observations of sea level pressure (SLP) and upper-air height to derive composite patterns of cyclonic cloud vortices for the Northern Hemisphere. The patterns reveal variations in the structure and implied dynamics of cyclonic systems at different stages of development that include: (1) increasing vertical symmetry of the lower-level and upper-air circulations and (2) decreasing lower-tropospheric thicknesses and temperature advection, associated with increasing age of the vortex. Cloud vortices are more intense in winter than in summer and typically reach maximum intensity in the short-lived prespiral signature stage. There are major structural differences among frontal wave, polar air, and 'instant occlusion' cyclogenesis types. Cyclones in the dissipation stage may reintensify (deepen), as denoted by the appearance in the imagery of an asymmetric cloud band or a tightened spiral vortex. The satellite-derived statistics on cloud vortex intensity, which are seasonal- and latitude- as well as type-dependent, are applied to a preliminary examination of the synoptic manifestations of seasonal climate variability. An apparently close relationship is found, for two winter and spring seasons, between Northern Hemisphere cyclonic activity and variations in cryosphere variables, particularly the extent of Arctic sea ice. The results may indicate that increased snow and ice extent accompany a southward displacement of cyclonic activity and/or a predominance of deeper systems. However, there is also a strong regional dependence to the ice-synoptics feedback. This study demonstrates the utility of high resolution meteorological satellite imagery for studies of climate variations (climate dynamics).

  10. The Polar Stratosphere in a Changing Climate (POLSTRACC)

    NASA Astrophysics Data System (ADS)

    Oelhaf, Hermann; Sinnhuber, Björn-Martin; Woiwode, Wolfgang; Rapp, Markus; Dörnbrack, Andreas; Engel, Andreas; Boenisch, Harald

    2015-04-01

    The POLSTRACC mission aims at providing new scientific knowledge on the Arctic lowermost stratosphere (LMS) and upper troposphere under the present load of halogens and state of climate variables. POLSTRACC is the only HALO (High Altitude and LOng Range Research Aircraft, German Research Community) mission dedicated to study the UTLS at high latitudes several years after the last intensive Arctic campaigns. The scientific scope of POLSTRACC will be broadened by its combination with the SALSA (Seasonality of Air mass transport and origin in the Lowermost Stratosphere using the HALO Aircraft) and GW-LCYCLE (Gravity Wave Life Cycle Experiment, a BMBF/ROMIC project) missions, which address complementary scientific goals sharing the same HALO payload. POLSTRACC, SALSA and GW-LCYCLE will offer the unique opportunity to study the bottom of the polar vortex and the high-latitude UTLS along with their impact on lower latitudes throughout an entire winter/spring cycle. The POLSTRACC consortium includes national (KIT, Forschungszentrum Jülich, DLR, Max Planck Institute for Chemistry, Universities of Frankfurt, Heidelberg, Mainz and Wuppertal) and international partners (e.g. NASA). The payload for the combined POLSTRACC, SALSA and GW-LCYCLE campaigns comprises an innovative combination of remote sensing techniques providing 2- and 3-D distributions of temperature and a large number of substances, and precise in-situ instruments measuring T, O3, H2O, tracers of different lifetimes and chemically active species at the aircraft level with high time-resolution. Drop sondes will add information about temperature, humidity and wind in the atmosphere underneath the aircraft. The field campaign will be divided into three phases for addressing (i) the early polar vortex and its wide-scale vicinity in December 2015 (from Oberpfaffenhofen, Germany), (ii) the mid-winter vortex from January to March 2016 (from Kiruna, Sweden), and (iii) the late dissipating vortex and its wide-scale vicinity in March 2016 (from Kiruna and Oberpfaffenhofen). The activities from Kiruna will be split into two intensive phases, with a focus on gravity wave observations in January 2016. Actual mission planning will be supported by flight planning and model tools and will be tested already in the preceding winter in a dry-run activity. The airborne field observations will be complemented by ground-based activities (e.g. lidars, radars and radio soundings) and satellite observations (e.g. CALIPSO, MLS and ACE-FTS). The Poster is intended to present an overview of the scientific objectives, the payload, and the mission rationale, and to attract international scientific groups to join the POLSTRACC framework and extend its scientific scope.

  11. Groundbased spectroscopic measurements of stratospheric NO[sub 2] and OClO in arctic winter 1989/90

    SciTech Connect

    Fiedler, M.; Frank, H.; Gomer, T.; Hausmann, M.; Pfeilsticker, K.; Platt, U.

    1993-05-21

    The authors report on column measurements of stratospheric nitrogen dioxide and OClO made near the arctic vortex. This is part of an effort to study ozone depletion effects in the artic region by looking for atmospheric signatures of gases which contribute to catalyzing ozone depletion, denitrification, and activation of halogen species. OClO is viewed as a sensitive indicator of activated halogene chemistry, since it is produced via chlorine oxide and bromine oxide interactions. It also is rapidly photolyzed. Using direct moonlight or zenith scattered sunlight, UV and visible spectroscopy was able to measure slant column integrated NO[sub 2] and OClO abundances, and convert them to vertical column densities. Elevated levels of OClO were detected during February 6, 8, 1990, when atmospheric temperatures may have favored formation of polar stratospheric clouds.

  12. The Arctic Research Consortium of the United States (ARCUS)

    NASA Astrophysics Data System (ADS)

    Creek, K. R.; Fox, S. E.; Wiggins, H. V.

    2010-12-01

    The Arctic Research Consortium of the United States (ARCUS) is a nonprofit membership organization composed of universities and institutions that have a substantial commitment to research in the Arctic. ARCUS was formed in 1988 to serve as a forum for planning, facilitating, coordinating, and implementing interdisciplinary studies of the Arctic; to act as a synthesizer and disseminator of scientific information on arctic research; and to educate scientists and the general public about the needs and opportunities for research in the Arctic. ARCUS, in collaboration with the broader science community, relevant agencies and organizations, and other stakeholders, coordinates science planning and educational activities across disciplinary and organizational boundaries. Examples of current ARCUS science planning activities include: serving as the project office for the multi-agency Study of Environmental Arctic Change (SEARCH) program, providing support to the related Bering Ecosystem Study (BEST), and serving as the Science Management Office for the National Science Foundation (NSF) Arctic System Science (ARCSS) Program. ARCUS’ central educational activity is PolarTREC (Teachers and Researchers Exploring and Collaborating), an International Polar Year (IPY) program whereby K-12 educators and researchers work together in hands-on field experiences in the Arctic and Antarctic to advance polar science education. Additional science planning, educational, information, and outreach activities include, among many others, the Witness the Arctic newsletter, the Arctic Visiting Speakers’ Series, the ArcticInfo listserve, the Internet Media Archive (IMA), and the annual Arctic Forum conference. More information about these and other ARCUS activities can be found at the ARCUS website at: http://www.arcus.org.

  13. The Arctic Research Consortium of the United States (ARCUS)

    NASA Astrophysics Data System (ADS)

    Wiggins, H. V.; Warnick, W. K.

    2008-12-01

    The Arctic Research Consortium of the United States (ARCUS) is a nonprofit membership organization composed of universities and institutions that have a substantial commitment to research in the Arctic. ARCUS was formed in 1988 to serve as a forum for planning, facilitating, coordinating, and implementing interdisciplinary studies of the Arctic; to act as a synthesizer and disseminator of scientific information on arctic research; and to educate scientists and the general public about the needs and opportunities for research in the Arctic. ARCUS, in collaboration with the broader science community, relevant agencies and organizations, and other stakeholders, coordinates science planning and educational activities across disciplinary and organizational boundaries. Examples of current ARCUS science planning activities include: serving as the project office for the multi- agency Study of Environmental Arctic Change (SEARCH) program, providing support to the related Bering Ecosystem Study (BEST), and serving as the Science Management Office for the National Science Foundation (NSF) Arctic System Science (ARCSS) Program. ARCUS" central educational activity is PolarTREC (Teachers and Researchers Exploring and Collaborating), an International Polar Year (IPY) program whereby K-12 educators and researchers work together in hands-on field experiences in the Arctic and Antarctic to advance polar science education. Additional science planning, educational, information, and outreach activities include, among many others, the Witness the Arctic newsletter, the Arctic Visiting Speakers" Series, the ArcticInfo listserve, the Internet Media Archive (IMA), and the annual Arctic Forum conference. More information about these and other ARCUS activities can be found at the ARCUS website at: http://www.arcus.org.

  14. The Arctic Research Consortium of the United States (ARCUS)

    NASA Astrophysics Data System (ADS)

    Fox, S. E.; Wiggins, H. V.; Creek, K. R.

    2009-12-01

    The Arctic Research Consortium of the United States (ARCUS) is a nonprofit membership organization composed of universities and institutions that have a substantial commitment to research in the Arctic. ARCUS was formed in 1988 to serve as a forum for planning, facilitating, coordinating, and implementing interdisciplinary studies of the Arctic; to act as a synthesizer and disseminator of scientific information on arctic research; and to educate scientists and the general public about the needs and opportunities for research in the Arctic. ARCUS, in collaboration with the broader science community, relevant agencies and organizations, and other stakeholders, coordinates science planning and educational activities across disciplinary and organizational boundaries. Examples of current ARCUS science planning activities include: serving as the project office for the multi-agency Study of Environmental Arctic Change (SEARCH) program, providing support to the related Bering Ecosystem Study (BEST), and serving as the Science Management Office for the National Science Foundation (NSF) Arctic System Science (ARCSS) Program. ARCUS’ central educational activity is PolarTREC (Teachers and Researchers Exploring and Collaborating), an International Polar Year (IPY) program whereby K-12 educators and researchers work together in hands-on field experiences in the Arctic and Antarctic to advance polar science education. Additional science planning, educational, information, and outreach activities include, among many others, the Witness the Arctic newsletter, the Arctic Visiting Speakers’ Series, the ArcticInfo listserve, the Internet Media Archive (IMA), and the annual Arctic Forum conference. More information about these and other ARCUS activities can be found at the ARCUS website at: http://www.arcus.org.

  15. Arctic Social Sciences: Opportunities in Arctic Research.

    ERIC Educational Resources Information Center

    Arctic Research Consortium of the United States, Fairbanks, AK.

    The U.S. Congress passed the Arctic Research and Policy Act in 1984 and designated the National Science Foundation (NSF) the lead agency in implementing arctic research policy. In 1989, the parameters of arctic social science research were outlined, emphasizing three themes: human-environment interactions, community viability, and rapid social…

  16. On the Influence of North Pacific Sea Surface Temperature on the Arctic Winter Climate

    NASA Technical Reports Server (NTRS)

    Hurwitz, Margaret M.; Newman, P. A.; Garfinkel, C. I.

    2012-01-01

    Differences between two ensembles of Goddard Earth Observing System Chemistry-Climate Model simulations isolate the impact of North Pacific sea surface temperatures (SSTs) on the Arctic winter climate. One ensemble of extended winter season forecasts is forced by unusually high SSTs in the North Pacific, while in the second ensemble SSTs in the North Pacific are unusually low. High Low differences are consistent with a weakened Western Pacific atmospheric teleconnection pattern, and in particular, a weakening of the Aleutian low. This relative change in tropospheric circulation inhibits planetary wave propagation into the stratosphere, in turn reducing polar stratospheric temperature in mid- and late winter. The number of winters with sudden stratospheric warmings is approximately tripled in the Low ensemble as compared with the High ensemble. Enhanced North Pacific SSTs, and thus a more stable and persistent Arctic vortex, lead to a relative decrease in lower stratospheric ozone in late winter, affecting the April clear-sky UV index at Northern Hemisphere mid-latitudes.

  17. Arctic Languages: An Awakening.

    ERIC Educational Resources Information Center

    Collis, Dermid R. F., Ed.

    This work is a study of Arctic languages written in an interdisciplinary manner. Part of the Unesco Arctic project aimed at safeguarding the linguistic heritage of Arctic peoples, the book is the outcome of three Unesco meetings at which conceptual approaches to and practical plans for the study of Arctic cultures and languages were worked out.…

  18. Crystalline geometries from a fermionic vortex lattice

    NASA Astrophysics Data System (ADS)

    Mohammadi Mozaffar, M. Reza; Mollabashi, Ali

    2014-02-01

    We study charged Dirac fermions on an AdS2×R2 background with a nonzero magnetic field. Under certain boundary conditions, we show that the charged fermion can make the background unstable, resulting in spontaneous formation of a vortex lattice. We observe that an electric field emerges in the backreacted solution due to the vortex lattice constructed from spin polarized fermions. This electric field may be extended to the UV boundary which leads to a finite charge density. We also discuss corrections to the thermodynamic functions due to the lattice formation.

  19. Estimation of polar low characteristics for the Nordic Seas for 1995-2008 using satellite data

    NASA Astrophysics Data System (ADS)

    Smirnova, Julia; Chapron, Bertrand; Zabolotskikh, Elizaveta; Leonid Bobylev, Mr

    In recent years the scientific research confirmed the fact of the global warming. The Arctic climate is warming even more rapidly. Powerful storm polar lows having wind speeds of about 25 m/c are known to be the cause of hazardous weather. Polar lows present themselves as the atmospheric phenomena the horizontal dimensions of which do not exceed 1,000 km, appear and which exist from 12 to 24 hours. The wave fall and low temperatures can lead to increased probability of vessel icing the intensity of which increases with the high wind speed and large wave height. Study of the mesoscale processes, such as polar lows in the Arctic has become especially relevant due to the sharp sea ice decreasing in the Arctic Ocean and Arctic seas in recent years. Only the use of satellite data allows obtaining regular and spacious information about the polar lows. Early detection and evaluation of the characteristics of the polar lows is an extremely important task to ensure the safety of navigation, fishing and oil industry in the Arctic region. With new open areas dangerous polar lows can arise over them. So early detection of the polar lows, studying their characteristics, tracking their movement and prediction presents one the most important problems of the modern science. The present-day meteorological observational network has severe limitations in detecting all, especially small mesoscale cyclones, so there is a strong need for new and/or improved methods to detect and monitor polar lows. Satellite remote sensing seems to be the most feasible tool for early detection and monitoring of the polar lows. Several remote sensing sensors are capable to detect a polar low but each of them suffers from various deficiencies. In the work, satellite passive microwave data have been intensively exploited aiming at obtaining the fields of geophysical parameters inside the polar lows. DMSP Special Sensor Microwave/Imager - SSM/I data were used in the research. The polar lows have been identified on satellite passive microwave imagery by fields of means of analysis of atmospheric water vapour fields using a new approach. This approach consists of two stages. During the first stage the total atmospheric water vapor fields are calculated from passive microwave measurements using precise retrieval Neural Network Algorithms (Bobylev et al., 2010). During the second stage the vortex structures are detected in these fields, and polar lows are identified and tracked. Based on this approach, were estimated polar low characteristics in the Nordic seas for the period of 1995 - 2008. All polar lows have been identified for this period on SSM/I imagery. Other satellite data, such as QuikSCAT SeaWinds, NOAA AVHRR were used as additional information for polar low parameter retrieval and analysis.

  20. In situ measurements of water vapor in the Arctic winter lower stratosphere

    NASA Astrophysics Data System (ADS)

    Spackman, James Ryan

    The Harvard Lyman-alpha photofragment fluorescence hygrometer measured water vapor aboard the NASA ER-2 aircraft during the SAGE III Ozone Loss and Validation Experiment (SOLVE), based from Kiruna, Sweden (68°N, 20°E), during January--March 2000. In situ measurements of water vapor, CH4, and N2O, acquired during SOLVE, are used to examine (1) dehydration in the Arctic vortex and (2) transport into the lowermost stratosphere in the context of middle- and high-latitude ozone declines. Knowledge of the total hydrogen budget of the Arctic winter stratosphere is pertinent to understanding the processes of formation of polar stratospheric clouds (PSCs) and quantifying the reactive uptake coefficients of the relevant cold aerosols, factors determining how fast reservoir halogen species (i.e., ClONO2, HCl) are converted to active forms (i.e., ClO, ClOOCl). Although the data indicate only isolated dehydration and rehydration episodes along ER-2 flight tracks (i.e., between 400 and 470 K) in the vortex, the relationship between H2O and CH4 for all flights during SOLVE suggests that subtle, widespread dehydration occurred above the ER-2 flight tracks, consistent with meteorological reanalysis data. Isentropic transport from the tropics plays a major role in redistributing ozone and water vapor at middle and high latitudes. Analysis of tracer-tracer correlations of the observed quantities H2O + 2*CH 4 and N2O indicates that rapid, poleward isentropic transport from the lower tropical stratosphere coupled with diabatic descent between the subtropical jet and polar jet delivers very young air to the high-latitude lowermost stratosphere during winter, while descent from the vortex and subsequent transport to lower latitudes is very limited. No evidence of isentropic mixing from the upper tropical troposphere survives in the high-latitude lowermost stratosphere except below 350 K, where markedly higher water vapor mixing ratios indicate mixing from the extratropical troposphere. The balance of all of these transport processes poses dynamical and chemical consequences for ozone. Transport from the lower tropical stratosphere (1) exports ozone-poor air to midlatitudes and the subvortex region and (2) distributes seasonally variable water vapor to the middle- and high-latitude lower stratosphere, potentially enhancing halogen-catalyzed ozone destruction through heterogeneous processing.

  1. Coarse mode aerosols in the High Arctic

    NASA Astrophysics Data System (ADS)

    Baibakov, K.; O'Neill, N. T.; Chaubey, J. P.; Saha, A.; Duck, T. J.; Eloranta, E. W.

    2014-12-01

    Fine mode (submicron) aerosols in the Arctic have received a fair amount of scientific attention in terms of smoke intrusions during the polar summer and Arctic haze pollution during the polar winter. Relatively little is known about coarse mode (supermicron) aerosols, notably dust, volcanic ash and sea salt. Asian dust is a regular springtime event whose optical and radiative forcing effects have been fairly well documented at the lower latitudes over North America but rarely reported for the Arctic. Volcanic ash, whose socio-economic importance has grown dramatically since the fear of its effects on aircraft engines resulted in the virtual shutdown of European civil aviation in the spring of 2010 has rarely been reported in the Arctic in spite of the likely probability that ash from Iceland and the Aleutian Islands makes its way into the Arctic and possibly the high Arctic. Little is known about Arctic sea salt aerosols and we are not aware of any literature on the optical measurement of these aerosols. In this work we present preliminary results of the combined sunphotometry-lidar analysis at two High Arctic stations in North America: PEARL (80°N, 86°W) for 2007-2011 and Barrow (71°N,156°W) for 2011-2014. The multi-years datasets were analyzed to single out potential coarse mode incursions and study their optical characteristics. In particular, CIMEL sunphotometers provided coarse mode optical depths as well as information on particle size and refractive index. Lidar measurements from High Spectral Resolution lidars (AHSRL at PEARL and NSHSRL at Barrow) yielded vertically resolved aerosol profiles and gave an indication of particle shape and size from the depolarization ratio and color ratio profiles. Additionally, we employed supplementary analyses of HYSPLIT backtrajectories, OMI aerosol index, and NAAPS (Navy Aerosol Analysis and Prediction System) outputs to study the spatial context of given events.

  2. The Remarkable 2003--2004 Winter and Other Recent Warm Winters in the Arctic Stratosphere Since the Late 1990s

    NASA Technical Reports Server (NTRS)

    Manney, Gloria L.; Kruger, Kirstin; Sabutis, Joseph L.; Sena, Sara Amina; Pawson, Steven

    2005-01-01

    The 2003-2004 Arctic winter was remarkable in the approximately 50-year record of meteorological analyses. A major warming beginning in early January 2004 led to nearly 2 months of vortex disruption with high-latitude easterlies in the middle to lower stratosphere. The upper stratospheric vortex broke up in late December, but began to recover by early January, and in February and March was the strongest since regular observations began in 1979. The lower stratospheric vortex broke up in late January. Comparison with 2 previous years, 1984-1985 and 1986-1987, with prolonged midwinter warming periods shows unique characteristics of the 2003-2004 warming period: The length of the vortex disruption, the strong and rapid recovery in the upper stratosphere, and the slow progression of the warming from upper to lower stratosphere. January 2004 zonal mean winds in the middle and lower stratosphere were over 2 standard deviations below average. Examination of past variability shows that the recent frequency of major stratospheric warmings (7 in the past 6 years) is unprecedented. Lower stratospheric temperatures were unusually high during 6 of the past 7 years, with 5 having much lower than usual potential for polar stratospheric cloud (PSC) formation and ozone loss (nearly none in 1998-1999, 2001-2002, and 2003-2004, and very little in 1997-1998 and 2000-2001). Middle and upper stratospheric temperatures, however, were unusually low during and after February. The pattern of 5 of the last 7 years with very low PSC potential would be expected to occur randomly once every 850 years. This cluster of warm winters, immediately following a period of unusually cold winters, may have important implications for possible changes in interannual variability and for determination and attribution of trends in stratospheric temperatures and ozone.

  3. Arctic Summer Ice Processes

    NASA Technical Reports Server (NTRS)

    Holt, Benjamin

    1999-01-01

    The primary objective of this study is to estimate the flux of heat and freshwater resulting from sea ice melt in the polar seas. The approach taken is to examine the decay of sea ice in the summer months primarily through the use of spaceborne Synthetic Aperture Radar (SAR) imagery. The improved understanding of the dynamics of the melt process can be usefully combined with ice thermodynamic and upper ocean models to form more complete models of ice melt. Models indicate that more heat is absorbed in the upper ocean when the ice cover is composed of smaller rather than larger floes and when there is more open water. Over the course of the summer, floes disintegrate by physical forcing and heating, melting into smaller and smaller sizes. By measuring the change in distribution of floes together with open water over a summer period, we can make estimates of the amount of heating by region and time. In a climatic sense, these studies are intended to improve the understanding of the Arctic heat budget which can then be eventually incorporated into improved global climate models. This work has two focus areas. The first is examining the detailed effect of storms on floe size and open water. A strong Arctic low pressure storm has been shown to loosen up the pack ice, increase the open water concentration well into the pack ice, and change the distribution of floes toward fewer and smaller floes. This suggests episodic melting and the increased importance of horizontal (lateral) melt during storms. The second focus area is related to an extensive ship-based experiment that recently took place in the Arctic called Surface Heat Budget of the Arctic (SHEBA). An icebreaker was placed purposely into the older pack ice north of Alaska in September 1997. The ship served as the base for experimenters who deployed extensive instrumentation to measure the atmosphere, ocean, and ice during a one-year period. My experiment will be to derive similar measurements (floe size, open water, temporal change) using spaceborne SAR data obtained during the summer of 1998, and compare these results with an ocean and ice model of summer melt. Additional information is contained in the original.

  4. The Age of the Arctic.

    ERIC Educational Resources Information Center

    Young, Oran R.

    1986-01-01

    Examines trends related to exploration in the Arctic by considering: (1) technology and military strategies; (2) foreign policy and the Arctic; (3) Arctic industrialization; (4) the Arctic policy agenda; and (5) recent United States initiatives in this region. (JN)

  5. Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations.

    PubMed

    Rode, Karyn D; Regehr, Eric V; Douglas, David C; Durner, George; Derocher, Andrew E; Thiemann, Gregory W; Budge, Suzanne M

    2014-01-01

    Polar bears (Ursus maritimus) have experienced substantial changes in the seasonal availability of sea ice habitat in parts of their range, including the Beaufort, Chukchi, and Bering Seas. In this study, we compared the body size, condition, and recruitment of polar bears captured in the Chukchi and Bering Seas (CS) between two periods (1986-1994 and 2008-2011) when declines in sea ice habitat occurred. In addition, we compared metrics for the CS population 2008-2011 with those of the adjacent southern Beaufort Sea (SB) population where loss in sea ice habitat has been associated with declines in body condition, size, recruitment, and survival. We evaluated how variation in body condition and recruitment were related to feeding ecology. Comparing habitat conditions between populations, there were twice as many reduced ice days over continental shelf waters per year during 2008-2011 in the SB than in the CS. CS polar bears were larger and in better condition, and appeared to have higher reproduction than SB bears. Although SB and CS bears had similar diets, twice as many bears were fasting in spring in the SB than in the CS. Between 1986-1994 and 2008-2011, body size, condition, and recruitment indices in the CS were not reduced despite a 44-day increase in the number of reduced ice days. Bears in the CS exhibited large body size, good body condition, and high indices of recruitment compared to most other populations measured to date. Higher biological productivity and prey availability in the CS relative to the SB, and a shorter recent history of reduced sea ice habitat, may explain the maintenance of condition and recruitment of CS bears. Geographic differences in the response of polar bears to climate change are relevant to range-wide forecasts for this and other ice-dependent species. PMID:23913506

  6. Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations

    USGS Publications Warehouse

    Rode, Karyn D.; Regehr, Eric V.; Douglas, David C.; Durner, George; Derocher, Andrew E.; Thiemann, Gregory W.; Budge, Suzanne M.

    2014-01-01

    Polar bears (Ursus maritimus) have experienced substantial changes in the seasonal availability of sea ice habitat in parts of their range, including the Beaufort, Chukchi, and Bering Seas. In this study, we compared the body size, condition, and recruitment of polar bears captured in the Chukchi and Bering Seas (CS) between two periods (1986–1994 and 2008–2011) when declines in sea ice habitat occurred. In addition, we compared metrics for the CS population 2008–2011 with those of the adjacent southern Beaufort Sea (SB) population where loss in sea ice habitat has been associated with declines in body condition, size, recruitment, and survival. We evaluated how variation in body condition and recruitment were related to feeding ecology. Comparing habitat conditions between populations, there were twice as many reduced ice days over continental shelf waters per year during 2008–2011 in the SB than in the CS. CS polar bears were larger and in better condition, and appeared to have higher reproduction than SB bears. Although SB and CS bears had similar diets, twice as many bears were fasting in spring in the SB than in the CS. Between 1986–1994 and 2008–2011, body size, condition, and recruitment indices in the CS were not reduced despite a 44-day increase in the number of reduced ice days. Bears in the CS exhibited large body size, good body condition, and high indices of recruitment compared to most other populations measured to date. Higher biological productivity and prey availability in the CS relative to the SB, and a shorter recent history of reduced sea ice habitat, may explain the maintenance of condition and recruitment of CS bears. Geographic differences in the response of polar bears to climate change are relevant to range-wide forecasts for this and other ice-dependent species.

  7. Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions

    NASA Astrophysics Data System (ADS)

    von Hobe, M.; Bekki, S.; Borrmann, S.; Cairo, F.; D'Amato, F.; Di Donfrancesco, G.; Dörnbrack, A.; Ebersoldt, A.; Ebert, M.; Emde, C.; Engel, I.; Ern, M.; Frey, W.; Griessbach, S.; Grooß, J.-U.; Gulde, T.; Günther, G.; Hösen, E.; Hoffmann, L.; Homonnai, V.; Hoyle, C. R.; Isaksen, I. S. A.; Jackson, D. R.; Jánosi, I. M.; Kandler, K.; Kalicinsky, C.; Keil, A.; Khaykin, S. M.; Khosrawi, F.; Kivi, R.; Kuttippurath, J.; Laube, J. C.; Lefèvre, F.; Lehmann, R.; Ludmann, S.; Luo, B. P.; Marchand, M.; Meyer, J.; Mitev, V.; Molleker, S.; Müller, R.; Oelhaf, H.; Olschewski, F.; Orsolini, Y.; Peter, T.; Pfeilsticker, K.; Piesch, C.; Pitts, M. C.; Poole, L. R.; Pope, F. D.; Ravegnani, F.; Rex, M.; Riese, M.; Röckmann, T.; Rognerud, B.; Roiger, A.; Rolf, C.; Santee, M. L.; Scheibe, M.; Schiller, C.; Schlager, H.; Siciliani de Cumis, M.; Sitnikov, N.; Søvde, O. A.; Spang, R.; Spelten, N.; Stordal, F.; Sumi?ska-Ebersoldt, O.; Viciani, S.; Volk, C. M.; vom Scheidt, M.; Ulanovski, A.; von der Gathen, P.; Walker, K.; Wegner, T.; Weigel, R.; Weinbuch, S.; Wetzel, G.; Wienhold, F. G.; Wintel, J.; Wohltmann, I.; Woiwode, W.; Young, I. A. K.; Yushkov, V.; Zobrist, B.; Stroh, F.

    2012-11-01

    Significant reductions in stratospheric ozone occur inside the polar vortices each spring when chlorine radicals produced by heterogeneous reactions on cold particle surfaces in winter destroy ozone mainly in two catalytic cycles, the ClO dimer cycle and the ClO/BrO cycle. Chlorofluorocarbons (CFCs), which are responsible for most of the chlorine currently present in the stratosphere, have been banned by the Montreal Protocol and its amendments, and the ozone layer is predicted to recover to 1980 levels within the next few decades. During the same period, however, climate change is expected to alter the temperature, circulation patterns and chemical composition in the stratosphere, and possible geo-engineering ventures to mitigate climate change may lead to additional changes. To realistically predict the response of the ozone layer to such influences requires the correct representation of all relevant processes. The European project RECONCILE has comprehensively addressed remaining questions in the context of polar ozone depletion, with the objective to quantify the rates of some of the most relevant, yet still uncertain physical and chemical processes. To this end RECONCILE used a broad approach of laboratory experiments, two field missions in the Arctic winter 2009/10 employing the high altitude research aircraft M55-Geophysica and an extensive match ozone sonde campaign, as well as microphysical and chemical transport modelling and data assimilation. Some of the main outcomes of RECONCILE are as follows: (1) vortex meteorology: the 2009/10 Arctic winter was unusually cold at stratospheric levels during the six-week period from mid-December 2009 until the end of January 2010, with reduced transport and mixing across the polar vortex edge; polar vortex stability and how it is influenced by dynamic processes in the troposphere has led to unprecedented, synoptic-scale stratospheric regions with temperatures below the frost point; in these regions stratospheric ice clouds have been observed, extending over >106km2 during more than 3 weeks. (2) Particle microphysics: heterogeneous nucleation of nitric acid trihydrate (NAT) particles in the absence of ice has been unambiguously demonstrated; conversely, the synoptic scale ice clouds also appear to nucleate heterogeneously; a variety of possible heterogeneous nuclei has been characterised by chemical analysis of the non-volatile fraction of the background aerosol; substantial formation of solid particles and denitrification via their sedimentation has been observed and model parameterizations have been improved. (3) Chemistry: strong evidence has been found for significant chlorine activation not only on polar stratospheric clouds (PSCs) but also on cold binary aerosol; laboratory experiments and field data on the ClOOCl photolysis rate and other kinetic parameters have been shown to be consistent with an adequate degree of certainty; no evidence has been found that would support the existence of yet unknown chemical mechanisms making a significant contribution to polar ozone loss. (4) Global modelling: results from process studies have been implemented in a prognostic chemistry climate model (CCM); simulations with improved parameterisations of processes relevant for polar ozone depletion are evaluated against satellite data and other long term records using data assimilation and detrended fluctuation analysis. Finally, measurements and process studies within RECONCILE were also applied to the winter 2010/11, when special meteorological conditions led to the highest chemical ozone loss ever observed in the Arctic. In addition to quantifying the 2010/11 ozone loss and to understand its causes including possible connections to climate change, its impacts were addressed, such as changes in surface ultraviolet (UV) radiation in the densely populated northern mid-latitudes.

  8. Expanded record of Quaternary oceanographic change: Amerasian Arctic Ocean

    USGS Publications Warehouse

    Ishman, S.E.; Polyak, L.V.; Poore, R.Z.

    1996-01-01

    Four sediment cores collected from the Northwind and Mendeleyev ridges, Arctic Ocean, from 1089 m to 1909 m water depth, provide an oceanographic record extending back into the Matuyama reversed polarity chron. Benthic foraminiferal analyses show four prominent assemblage zones: Bolivina arctica, Cassidulina teretis, Bulimina aculeata, and Oridorsalis tener from the upper Matuyama reversed polarity chronozone through the Brunhes normal polarity chronozone. These assemblage zones represent depth-dependent benthic foraminiferal biofacies changes associated with oceanographic events that occurred in the Amerasian basin at ??? 780 and 300 ka, and indicate oceanographic influence from the North Atlantic. Recognition of these benthic assemblage zones in Arctic cores from the Alpha Ridge indicates that the benthic foraminiferal zonations in intermediate to deep water (>1000 m) Arctic cores may be more useful than preexisting lithostratigraphic zonations and should provide important information pertaining to the Quaternary paleoceanographic evolution of the Arctic Ocean.

  9. Vortex cutting in superconductors

    NASA Astrophysics Data System (ADS)

    Vlasko-Vlasov, Vitalii K.; Koshelev, Alexei E.; Glatz, Andreas; Welp, Ulrich; Kwok, Wai-K.

    2015-03-01

    Unlike illusive magnetic field lines in vacuum, magnetic vortices in superconductors are real physical strings, which interact with the sample surface, crystal structure defects, and with each other. We address the complex and poorly understood process of vortex cutting via a comprehensive set of magneto-optic experiments which allow us to visualize vortex patterns at magnetization of a nearly twin-free YBCO crystal by crossing magnetic fields of different orientations. We observe a pronounced anisotropy in the flux dynamics under crossing fields and the filamentation of induced supercurrents associated with the staircase vortex structure expected in layered cuprates, flux cutting effects, and angular vortex instabilities predicted for anisotropic superconductors. At some field angles, we find formation of the vortex domains following a type-I phase transition in the vortex state accompanied by an abrupt change in the vortex orientation. To clarify the vortex cutting scenario we performed time-dependent Ginzburg-Landau simulations, which confirmed formation of sharp vortex fronts observed in the experiment and revealed a left-handed helical instability responsible for the rotation of vortices. This work was supported by the U.S. Department of Energy, Office of Science, Materials Sciences and Engineering Division.

  10. Defining the Vortex Boundary Using N2O Measurements

    NASA Technical Reports Server (NTRS)

    Greenblatt, Jeffery; Jost, Hans-Jurg; Loewenstein, Max; Podolske, James R.; Newman, Paul A.; Lait, Leslie R.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    Defining the stratospheric vortex boundary is typically done using; the Nash criterion,(a) which determines the maximum gradient of Ertel's potential vorticity (EPV) in the vicinity of maximum zonal winds. However, such a procedure is insensitive to small-scale variations near the boundary, because EPV maps rely on interpolation from sparse data, and are therefore only accurate over large areas. An examination was made of high-speed N2O measurements during SOLVE, from Argus ER-2 flights across the vortex boundary in the 1999-2000 Arctic winter, to see whether sharp changes in N2O concentrations co-occur sufficiently well with the Nash definition of the vortex edge to serve as a reliable alternate definition.

  11. Dynamic decay of a single vortex into vortex-antivortex pairs

    NASA Astrophysics Data System (ADS)

    Lendínez, Sergi; Jain, Shikha; Novosad, Valentyn; Fradin, Frank Y.; Pearson, John E.; Tejada, Javier; Bader, Samuel D.

    2014-05-01

    A variety of metastable states, including vortices, antivortices, and their combinations, is typical for magnetically soft, thin films and patterned structures. The physics of individual spin vortices in patterned structures has been rather extensively explored. In contrast, there are few studies of the vortex-antivortex-vortex (v-av-v) system, in part because the configuration is rather challenging to obtain experimentally. We demonstrate herein how a recently proposed resonant-spin-ordering technique can be used to induce the dynamic decay of a single vortex into v-av states in elongated elements. The approach is based on first driving the system from the linear regime of constant vortex gyrations to the non-linear regime of vortex-core reversals at a fixed excitation frequency, and then subsequently reducing the excitation field back to the linear regime. This procedure stabilizes the system into a v-av-v state that is completely decoupled from the initialization excitation frequency. The newly acquired state is stable in remanence. The dynamic response of this system is expected to demonstrate a number of collective modes, depending on the combination of the vortex core polarities, and/or the excitation field direction, and, hence, is of interest for future studies.

  12. Ferroelectric nanostructure having switchable multi-stable vortex states

    DOEpatents

    Naumov, Ivan I. (Fayetteville, AR); Bellaiche, Laurent M. (Fayetteville, AR); Prosandeev, Sergey A. (Fayetteville, AR); Ponomareva, Inna V. (Fayetteville, AR); Kornev, Igor A. (Fayetteville, AR)

    2009-09-22

    A ferroelectric nanostructure formed as a low dimensional nano-scale ferroelectric material having at least one vortex ring of polarization generating an ordered toroid moment switchable between multi-stable states. A stress-free ferroelectric nanodot under open-circuit-like electrical boundary conditions maintains such a vortex structure for their local dipoles when subject to a transverse inhomogeneous static electric field controlling the direction of the macroscopic toroidal moment. Stress is also capable of controlling the vortex's chirality, because of the electromechanical coupling that exists in ferroelectric nanodots.

  13. Reconstruction of Arctic surface temperature in past 100 years using DINEOF

    NASA Astrophysics Data System (ADS)

    Zhang, Qiyi; Huang, Jianbin; Luo, Yong

    2015-04-01

    Global annual mean surface temperature has not risen apparently since 1998, which is described as global warming hiatus in recent years. However, measuring of temperature variability in Arctic is difficult because of large gaps in coverage of Arctic region in most observed gridded datasets. Since Arctic has experienced a rapid temperature change in recent years that called polar amplification, and temperature risen in Arctic is faster than global mean, the unobserved temperature in central Arctic will result in cold bias in both global and Arctic temperature measurement compared with model simulations and reanalysis datasets. Moreover, some datasets that have complete coverage in Arctic but short temporal scale cannot show Arctic temperature variability for long time. Data Interpolating Empirical Orthogonal Function (DINEOF) were applied to fill the coverage gap of NASA's Goddard Institute for Space Studies Surface Temperature Analysis (GISTEMP 250km smooth) product in Arctic with IABP dataset which covers entire Arctic region between 1979 and 1998, and to reconstruct Arctic temperature in 1900-2012. This method provided temperature reconstruction in central Arctic and precise estimation of both global and Arctic temperature variability with a long temporal scale. Results have been verified by extra independent station records in Arctic by statistical analysis, such as variance and standard deviation. The result of reconstruction shows significant warming trend in Arctic in recent 30 years, as the temperature trend in Arctic since 1997 is 0.76°C per decade, compared with 0.48°C and 0.67°C per decade from 250km smooth and 1200km smooth of GISTEMP. And global temperature trend is two times greater after using DINEOF. The discrepancies above stress the importance of fully consideration of temperature variance in Arctic because gaps of coverage in Arctic cause apparent cold bias in temperature estimation. The result of global surface temperature also proves that global warming in recent years is not as slow as thought.

  14. Electrostatically Enhanced Vortex Separator

    NASA Technical Reports Server (NTRS)

    Collins, Earl R.

    1993-01-01

    Proposed device removes fine particles from high-pressure exhaust gas of chemical reactor. Negatively charged sectors on rotating disks in vortex generator attracts positively charged particles from main stream of exhaust gas. Electrostatic charge enhances particle-separating action of vortex. Gas without particles released to atmosphere.

  15. Scientist Examines Tornado Vortex

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In this Quick Time movie, a scientist examines what appears to be a tornado vortex (blue) coming out of a thunderstorm. The scientist uses 3D glasses to be able to see in 3 dimensions the different flows going out into the vortex. Earth science and weather studies are an important ongoing function of NASA and its affiliates.

  16. Improved vortex reactor system

    DOEpatents

    Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)

    1995-01-01

    An improved vortex reactor system for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor.

  17. Oregon Zoo Polar Bear

    USGS Multimedia Gallery

    Tasul, an Oregon Zoo polar bear, sports a high-tech collar that will help researchers study her endangered wild counterparts in the Arctic. Photo by Michael Durham, courtesy of the Oregon Zoo. Photo by Michael Durham, courtesy of the Oregon Zoo....

  18. Vortex control: Further encounters

    NASA Technical Reports Server (NTRS)

    Rao, Dhanvada M.

    1991-01-01

    The progress of continuing investigations on vortex control techniques is updated. The following topics are briefly discussed: (1) vortex flaps adapted for high-alpha control; (2) alleviation of leading edge extension (LEX) vortex induced twin-tail buffet; (3) controlled decoupling of interactive forebody chine and wing vortices; (4) forebody vortex manipulation by mechanical and pneumatic techniques; and (5) stall-departure alleviation of high aspect-ratio wings. Salient results of exploratory low speed wind tunned experiments are presented. The investigations, primarily aimed at concept validation, were performed on generic configurations utilizing flow visualizations and pressure and balance measurements. Selected results illustrate the efficacy and potential for development of specific vortex control concepts for improved high-alpha configuration aerodynamics.

  19. Vortex-antivortex dynamics driven by spin-torque in a nanocontact

    NASA Astrophysics Data System (ADS)

    Zaspel, C. E.; Kireev, V. E.

    2015-10-01

    A spin-polarized current in a nanocontact has been shown to induce the formation of a magnetic vortex at the nanocontact by the Oersted field, and spin-torque drives the vortex core in an elliptical orbit about the nanocontact. For the case of an external in-plane magnetic field in an extended free layer, the magnetization will be uniform far from the nanocontact, implying that vortex formation must be accompanied by the formation of an antivortex. Using the Thiele approach to describe the vortex-antivortex dynamics it is shown that the frequency of gyrotropic motion of the vortex is a function of the nanocontact current which is linear for large vortex-antivortex separations and it becomes nonlinear as the separation is decreased. The equilibrium vortex -antivortex separation can be controlled by the nanocontact current as well as the external magnetic field.

  20. High Speed Vortex Flows

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Wilcox, Floyd J., Jr.; Bauer, Steven X. S.; Allen, Jerry M.

    2000-01-01

    A review of the research conducted at the National Aeronautics and Space Administration (NASA), Langley Research Center (LaRC) into high-speed vortex flows during the 1970s, 1980s, and 1990s is presented. The data reviewed is for flat plates, cavities, bodies, missiles, wings, and aircraft. These data are presented and discussed relative to the design of future vehicles. Also presented is a brief historical review of the extensive body of high-speed vortex flow research from the 1940s to the present in order to provide perspective of the NASA LaRC's high-speed research results. Data are presented which show the types of vortex structures which occur at supersonic speeds and the impact of these flow structures to vehicle performance and control is discussed. The data presented shows the presence of both small- and large scale vortex structures for a variety of vehicles, from missiles to transports. For cavities, the data show very complex multiple vortex structures exist at all combinations of cavity depth to length ratios and Mach number. The data for missiles show the existence of very strong interference effects between body and/or fin vortices and the downstream fins. It was shown that these vortex flow interference effects could be both positive and negative. Data are shown which highlights the effect that leading-edge sweep, leading-edge bluntness, wing thickness, location of maximum thickness, and camber has on the aerodynamics of and flow over delta wings. The observed flow fields for delta wings (i.e. separation bubble, classical vortex, vortex with shock, etc.) are discussed in the context of' aircraft design. And data have been shown that indicate that aerodynamic performance improvements are available by considering vortex flows as a primary design feature. Finally a discussing of a design approach for wings which utilize vortex flows for improved aerodynamic performance at supersonic speed is presented.

  1. Measurements of Chlorine Partitioning in the Winter Arctic Stratosphere

    NASA Technical Reports Server (NTRS)

    Stachnik, R.; Salawitch, R.; Engel, A.; Schmidt, U.

    1999-01-01

    Under the extremely cold conditions in the polar winter stratosphere, heterogeneous reactions involving HCl and CIONO(sub 2) on the surfaces of polar stratospheric cloud particles can release large amounts of reactive chlorine from these reservoirs leading to rapid chemical loss of ozone in the Arctic lower stratosphere during late winter and early spring.

  2. Arctic polynyas

    NASA Astrophysics Data System (ADS)

    Alexander, Vera; Muench, Robin

    Polynyas are areas of open water that occur at specific, recurrent locations in the polar regions and that are surrounded by ice-covered waters. They have been of interest historically because they are centers of upper trophic level biological activity and were consequently foci of both commercial whaling activities and of native subsistence hunting. They have more recently become of interest from a basic research viewpoint because they are typified by intensive biological activity and energetic physical processes. They are similar, in many respects, to the marginal ice zones, which are an ongoing focus of considerable oceanographic research. Polynyas can be conceptually envisaged as polar oceanic “oases” in which biological activities are focused locally while they are surrounded by relatively unproductive waters. Polynyas serve as outposts of enhanced production within the pack ice remote from the biologically rich marginal ice zones.

  3. Islands of the Arctic

    NASA Astrophysics Data System (ADS)

    Overpeck, Jonathan

    2004-02-01

    Few environments on Earth are changing more dramatically than the Arctic. Sea ice retreat and thinning is unprecedented in the period of the satellite record. Surface air temperatures are the warmest in centuries. The biology of Arctic lakes is changing like never before in millennia. Everything is pointing to the meltdown predicted by climate model simulations for the next 100 years. At the same time, the Arctic remains one of the most pristine and beautiful places on Earth. For both those who know the Arctic and those who want to know it, this book is worth its modest price. There is much more to the Arctic than its islands, but there's little doubt that Greenland and the major northern archipelagos can serve as a great introduction to the environment and magnificence of the Arctic. The book uses the islands of the Arctic to give a good introduction to what the Arctic environment is all about. The first chapter sets the stage with an overview of the geography of the Arctic islands, and this is followed by chapters that cover many key aspects of the Arctic: the geology (origins), weather and climate, glaciers, ice sheets, sea ice, permafrost and other frozen ground issues, coasts, rivers, lakes, animals, people, and environmental impacts. The material is pitched at a level well suited for the interested layperson, but the book will also appeal to those who study the science of the Arctic.

  4. The Arctic Research Program: International

    E-print Network

    Arctic Research Program/COD/CPO #12;Arctic Research Program- Ocean-Ecosystem Observations GOALS: 2004 of the Arctic from an ice covered ocean to an ocean where ice may disappear in the summer. . · To facilitate and deploy Arctic system-wide observing tools to track Pan-Arctic ice-ocean-ecosystem changes and impacts (3

  5. Oceanic and atmospheric transport of multiyear El Niño-Southern Oscillation (ENSO) signatures to the polar regions

    NASA Astrophysics Data System (ADS)

    Jevrejeva, S.; Moore, J. C.; Grinsted, A.

    2004-12-01

    Using Monte-Carlo Singular Spectrum Analysis (MC- SSA) and Wavelet Transform (WT) we separate statistically significant components from time series and demonstrate significant co-variance and consistent phase differences between ice conditions and the Arctic Oscillation and Southern Oscillation indices (AO and SOI) at 2.2, 3.5, 5.7 and 13.9 year periods. The 2.2, 3.5 and 5.7 year signals detected in the Arctic are generated about three months earlier in the tropical Pacific Ocean. In contrast, we show that the 13.9 year signal propagates eastward from the western Pacific as equatorial coupled waves (ECW, 0.13-0.15 ms-1), and then as fast boundary waves (1-3 ms-1) along the western margins of the Americas, with a phase difference of about 1.8-2.1 years by the time they reach the Arctic. Our results provide evidence of dynamical connections between high latitude surface conditions, tropical ocean sea surface temperatures mediated by tropical wave propagation, the wintertime polar vortex and the AO.

  6. The Arctic Grand Challenge: Abrupt Climate Change

    NASA Astrophysics Data System (ADS)

    Wilkniss, P. E.

    2003-12-01

    Trouble in polar paradise (Science, 08/30/02), significant changes in the Arctic environment are scientifically documented (R.E. Moritz et al. ibid.). More trouble, lots more, "abrupt climate change," (R. B. Alley, et al. Science 03/28/03). R. Corell, Arctic Climate Impact Assessment team (ACIA), "If you want to see what will happen in the rest of the world 25 years from now just look what's happening in the Arctic," (Arctic Council meeting, Iceland, 08/03). What to do? Make abrupt Arctic climate change a grand challenge for the IPY-4 and beyond! Scientifically:Describe the "state" of the Arctic climate system as succinctly as possible and accept it as the point of departure.Develop a hypothesis and criteria what constitutes "abrupt climate change," in the Arctic that can be tested with observations. Observations: Bring to bear existing observations and coordinate new investments in observations through an IPY-4 scientific management committee. Make the new Barrow, Alaska, Global Climate Change Research Facility a major U.S. contribution and focal point for the IPY-4 in the U.S Arctic. Arctic populations, Native peoples: The people of the North are living already, daily, with wrenching change, encroaching on their habitats and cultures. For them "the earth is faster now," (I. Krupnik and D. Jolly, ARCUS, 2002). From a political, economic, social and entirely realistic perspective, an Arctic grand challenge without the total integration of the Native peoples in this effort cannot succeed. Therefore: Communications must be established, and the respective Native entities must be approached with the determination to create well founded, well functioning, enduring partnerships. In the U.S. Arctic, Barrow with its long history of involvement and active support of science and with the new global climate change research facility should be the focal point of choice Private industry: Resource extraction in the Arctic followed by oil and gas consumption, return the combustion products as greenhouse gases to their regions of origin. Thus multinational company operations are affected by their own activities. There is a strong, convincing case, that these industrial giants must be involved in Arctic partnerships of the grand challenge. A most instructive, very successful example is the collaboration by the chemical companies after the discovery of the polar ozone holes, followed by the replacement of the culprit chlorofluorocarbon compounds. Public relations and involvement/education: The IPY offers a unique opportunity to showcase and drive home, into homes, the seriousness of the issue, Hollywood/Madison Avenue/ NASA style, nothing else will do. Ultimately we need to be mindful that "civilizations are ephemeral compared to species. -What we need is a primer on science, clearly written and unambiguous in its meaning-a primer for anyone interested in the state of the Earth and how to survive and live well on it." (James Lovelock, Science, 08/05/98). - Let's start in the Arctic-NOW.

  7. High concentrations of exopolymeric substances in Arctic winter sea ice: implications for the polar ocean carbon cycle and cryoprotection of diatoms

    NASA Astrophysics Data System (ADS)

    Krembs, C.; Eicken, H.; Junge, K.; Deming, J. W.

    2002-12-01

    Exopolymeric substances (EPS) produced by microorganisms play important roles in various aquatic, porous, and extreme environments. Only recently has their occurrence in sea ice been considered. We used macroscopic and microscopic approaches to study the content and possible ecological role of EPS in wintertime fast ice near Barrow, Alaska (71°20' N, 156°40' W). Using Alcian blue staining of melted ice samples, we observed high concentrations of EPS in all samples examined, ranging from 0.79 to 7.71 mg xanthan gum equivalents (XGEQV) l -1. Areal conversions to carbon equivalents yielded 1.5-1.9 g C m -2 ice in March and 3.3-4.0 g C m -2 in May (when the ice was thicker). Although EPS did not correlate with macronutrient or pigment data, the latter analyses indicated ongoing or recent biological activity in the ice within temperature horizons of -11°C to -9°C and warmer. EPS correlated positively with bacterial abundance (although no functional relationship could be deduced) and with dissolved organic carbon (DOC) concentrations. Ratios of EPS/DOC decreased at colder temperatures within the core, arguing against physical conversion of DOC to EPS during freezing. When sea-ice segments were maintained at representative winter temperatures (-5°C,-15°C and -25°C) for 3-14 months, the total EPS content increased significantly at rates of 5-47 ?g XGEQV l -1 d -1, similar to published rates of EPS production by diatoms. Microscopic images of ice-core sections at these very cold temperatures, using a recently developed non-invasive method, revealed diatoms sequestered in spacious brine pockets, intact autofluorescent chloroplasts in 47% of the (pennate) diatoms observed, and indications of mucus in diatom-containing pores. The high concentrations of EPS detected in these winter ice cores represent a previously unrecognized form of organic matter that may contribute significantly to polar ocean carbon cycles, not only within the ice but after springtime release into the water column. The EPS present in very high concentrations in the brine of these microhabitats appear to play important buffering and cryoprotectant roles for microorganisms, especially diatoms, against harsh winter conditions of high salinity and potential ice-crystal damage.

  8. NASA wake vortex research

    NASA Technical Reports Server (NTRS)

    Stough, H. P., III; Greene, George C.; Stewart, Eric C.; Stuever, Robert A.; Jordan, Frank L., Jr.; Rivers, Robert A.; Vicroy, Dan D.

    1993-01-01

    NASA is conducting research that will enable safe improvements in the capacity of the nation's air transportation system. The wake-vortex hazard is a factor in establishing the minimum safe spacing between aircraft during landing and takeoff operations and, thus, impacts airport capacity. The ability to accurately model the wake hazard and determine safe separation distances for a wide range of aircraft and operational scenarios may provide the basis for significant increases in airport capacity. Current and planned NASA research is described which is focused on increasing airport capacity by safely reducing wake-hazard-imposed aircraft separations through advances in a number of technologies including vortex motion and decay prediction, vortex encounter modeling, wake-vortex hazard characterization, and in situ flow sensing.

  9. Magnetic vortex oscillators

    NASA Astrophysics Data System (ADS)

    Hrkac, Gino; Keatley, Paul S.; Bryan, Matthew T.; Butler, Keith

    2015-11-01

    The magnetic vortex has sparked the interest of the academic and industrial communities over the last few decades. From their discovery in the 1970s for bubble memory devices to their modern application as radio frequency oscillators, magnetic vortices have been adopted to modern telecommunication and sensor applications. Basic properties of vortex structures in the static and dynamic regime, from a theoretical and experimental point of view, are presented as well as their application in spin torque driven nano-pillar and magnetic tunnel junction devices. Single vortex excitations and phase locking phenomena of coupled oscillators are discussed with an outlook of vortex oscillators in magnetic hybrid structures with imprinted domain confinement and dynamic encryption devices.

  10. Improved vortex reactor system

    DOEpatents

    Diebold, J.P.; Scahill, J.W.

    1995-05-09

    An improved vortex reactor system is described for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor. 12 figs.

  11. Atmospheric-wake vortex interactions

    NASA Technical Reports Server (NTRS)

    Bilanin, A. J.; Hirsh, J. E.; Teske, M. E.; Hecht, A. M.

    1978-01-01

    The interactions of a vortex wake with a turbulent stratified atmosphere are investigated with the computer code WAKE. It is shown that atmospheric shear, turbulence, and stratification can provide the dominant mechanisms by which vortex wakes decay. Computations included the interaction of a vortex wake with a viscous ground plane. The observed phenomenon of vortex bounce is explained in terms of secondary vorticity produced on the ground. This vorticity is swept off the ground and advected about the vortex pair, thereby altering the classic hyperbolic trajectory. The phenomenon of the solitary vortex is explained as an interaction of a vortex with crosswind shear. Here, the vortex having the sign opposite that of the sign of the vorticity in the shear is dispersed by a convective instability. This instability results in the rapid production of turbulence which in turn disperses the smoke marking the vortex.

  12. Carbon dynamics in arctic vegetation 

    E-print Network

    Street, Lorna Elizabeth

    2011-11-24

    Rapid climate change in Arctic regions is of concern due to important feedbacks between the Arctic land surface and the global climate system. A large amount of organic carbon (C) is currently stored in Arctic soils; if ...

  13. Carbon dioxide in Arctic and subarctic regions

    SciTech Connect

    Gosink, T. A.; Kelley, J. J.

    1981-03-01

    A three year research project was presented that would define the role of the Arctic ocean, sea ice, tundra, taiga, high latitude ponds and lakes and polar anthropogenic activity on the carbon dioxide content of the atmosphere. Due to the large physical and geographical differences between the two polar regions, a comparison of CO/sub 2/ source and sink strengths of the two areas was proposed. Research opportunities during the first year, particularly those aboard the Swedish icebreaker, YMER, provided additional confirmatory data about the natural source and sink strengths for carbon dioxide in the Arctic regions. As a result, the hypothesis that these natural sources and sinks are strong enough to significantly affect global atmospheric carbon dioxide levels is considerably strengthened. Based on the available data we calculate that the whole Arctic region is a net annual sink for about 1.1 x 10/sup 15/ g of CO/sub 2/, or the equivalent of about 5% of the annual anthropogenic input into the atmosphere. For the second year of this research effort, research on the seasonal sources and sinks of CO/sub 2/ in the Arctic will be continued. Particular attention will be paid to the seasonal sea ice zones during the freeze and thaw periods, and the tundra-taiga regions, also during the freeze and thaw periods.

  14. CANOZE measurements of the Arctic ozone hole

    NASA Technical Reports Server (NTRS)

    Evans, W. F. J.; Kerr, J. B.; Fast, H.

    1988-01-01

    In CANOZE 1 (Canadian Ozone Experiment), a series of 20 ozone profile measurements were made in April, 1986 from Alert at 82.5 N. CANOZE is the Canadian program for study of the Arctic winter ozone layer. In CANOZE 2, ozone profile measurements were made at Saskatoon, Edmonton, Churchill and Resolute during February and March, 1987 with ECC ozonesondes. Ground based measurements of column ozone, nitrogen dioxide and hydrochloric acid were conducted at Saskatoon. Two STRATOPROBE balloon flights were conducted on February 26 and March 19, 1987. Two aerosol flights were conducted by the University of Wyoming. The overall results of this study will be reported and compared with the NOZE findings. The results from CANOZE 3 in 1988, are also discussed. In 1988, as part of CANOZE 3, STRATOPROBE balloon flights were conducted from Saskatchewan on January 27 and February 13. A new lightweight infrared instrument was developed and test flown. A science flight was successfully conducted from Alert (82.5 N) on March 9, 1988 when the vortex was close to Alert; a good measurement of the profile of nitric acid was obtained. Overall, the Arctic spring ozone layer exhibits many of the features of the Antarctic ozone phenomenon, although there is obviously not a hole present every year. The Arctic ozone field in March, 1986 demonstrated many similarities to the Antarctic ozone hole. The TOMS imagery showed a crater structure in the ozone field similar to the Antarctic crater in October. Depleted layers of ozone were found in the profiles around 15 km, very similar to those reported from McMurdo. Enhanced levels of nitric acid were measured in air which had earlier been in the vortex. The TOMS imagery for March 1987 did not show an ozone crater, but will be examined for an ozone crater in February and March, 1988, the target date for the CANOZE 3 project.

  15. Development of Exhibit on Arctic Climate Change Called The Arctic: A Friend Acting Strangely Exhibition

    Sc