Georg Mayr - Academia.edu (original) (raw)
Papers by Georg Mayr
Annals of The Rheumatic Diseases, 2011
ObjectiveMicro RNAs (miRNAs) are a new class of regulatory elements. Altered expression of miRNAs... more ObjectiveMicro RNAs (miRNAs) are a new class of regulatory elements. Altered expression of miRNAs has been demonstrated in inflamed joints of patients suffering from rheumatoid arthritis (RA). However, the exact role of miRNAs in the pathogenesis of this disease has not been defined so far.MethodsCollagen induced arthritis (CIA) and K/BxN serum transfer arthritis was induced in wt and miR155−/− mice.
ABSTRACT Precipitation in mountainous regions is an essential process in meteorological research ... more ABSTRACT Precipitation in mountainous regions is an essential process in meteorological research for its strong impact on the hydrological cycle. To support scientists, we present the design of a meteorological application using the ASKALON environment comprising graphical workflow modeling and execution in a Cloud computing environment. We illustrate performance results that demonstrate that, although limited by Amdahl's law, our workflow can gain important speedup when executed in a virtualized Cloud environment with important operational cost reductions. Results from the meteorological research show the usefulness of our model for determining precipitation distribution in the case of two field campaigns over Norway.
2014 IEEE 3rd International Conference on Cloud Networking (CloudNet), 2014
Quarterly Journal of the Royal Meteorological Society, 2008
ABSTRACT This study investigates the onset phase of a strong Adriatic bora windstorm that occurre... more ABSTRACT This study investigates the onset phase of a strong Adriatic bora windstorm that occurred on 4 April 2002. The target area is a gap about 20 km wide embedded in the coastal mountain barrier of the Dinaric Alps that favours strong jet-like winds. Airborne-aerosol back-scatter lidar measurements on board the DLR Falcon research aircraft, together with surface and upper-air observations, are used to verify high-resolution numerical experiments conducted with the mesoscale atmospheric model RAMS and a single-layer shallow-water model (SWM). Especially during the breakthrough phase of the bora, the flow at the gap exit exhibits a complex spatial structure and temporal evolution. On a transect through the centre of the gap, a hydraulic jump forms; this is located close to the coast throughout the night, and starts to propagate downstream in the early morning. On a transect through the edge of the gap, a lee-wave-induced rotor becomes established, due to boundary-layer separation. It starts to propagate downstream about two hours after the jump. This flow evolution implies that the onset of strong winds at the coast occurs several hours earlier downstream of the centre of the gap than downwind of the edge of the gap. Consequently, the wind field in the vicinity of Rijeka airport, located downwind of the gap, is strongly inhomogeneous and transient, and represents a potential hazard to aviation. Measured bora winds at the surface exceed 20 ms−1, and the simulated wind speed in the gap wind layer exceeds 30 ms−1. The simulated turbulent kinetic energy exceeds 10 m2 s−2.RAMS indicates that wave-breaking near a critical level is the dominant mechanism for the generation of the windstorm. Gap jets can be identified downstream of several mountain passes. The simulated wave pattern above the Dinaric Alps, the wave decay with height due to directional wind shear and the strong flow descent on the leeward side of the barrier are supported by measured back-scatter intensities. Basic bora flow features, including gap jets and jumps, are remarkably well reproduced by SWM simulations. The RAMS reference run captures observed flow phenomena and the temporal flow evolution qualitatively well. A cold low-level bias, an overestimated bora inversion strength, and a slightly too-early bora onset are probably related to insufficient turbulent mixing in the boundary layer. The amplitude of trapped gravity waves, the time of the bora breakthrough and the inversion strength are found to be quite sensitive to the turbulence parametrization. Copyright © 2008 Royal Meteorological Society
Quarterly Journal of the Royal Meteorological Society, 2010
Quarterly Journal of the Royal Meteorological Society, 2007
Quarterly Journal of the Royal Meteorological Society, 2007
Quarterly Journal of the Royal Meteorological Society, 2004
Quarterly Journal of the Royal Meteorological Society, 2005
ABSTRACT A detailed analysis of bora winds is presented that were observed on 28 March 2002 in th... more ABSTRACT A detailed analysis of bora winds is presented that were observed on 28 March 2002 in the north-eastern part of the Adriatic Sea. Very high-resolution numerical simulations are compared with airborne, surface, and balloon observations. The key instrument for the verification of the numerical results is an aerosol backscatter lidar on board the DLR Falcon research aircraft. The high spatial resolution of the model and of the observational dataset allows several small-scale aspects of the bora winds to be explored. The study emphasises the great impact of boundary-layer effects including convective mixing and surface friction on the structure of the bora flow.The numerical model reveals that the diurnal cycle of the planetary boundary layer causes a diurnal variation of the gravity-wave amplitude and consequently a variation in the bora strength. The downslope flow is strongest during the night-time when the impinging air mass is stably stratified and exhibits a low-level jet. The bora strength weakens during the daytime due to the evolution of a neutrally stratified convective boundary layer. Lidar observations and simulations both suggest that the observed bora winds are driven by the dynamics of orographic gravity waves. In the deep north-easterly cross-mountain flow steeply amplified but non-breaking gravity waves as well as trapped lee waves are found throughout the troposphere. Vertical separation of the boundary layer over the steep leeward terrain slope prevents the bora flow from reaching the coast. As a result, the flow is kept aloft in a series of at least three unsteady trapped lee waves before it reattaches to the surface over the sea downstream of the mountains. No clear evidence is found for the existence of low-level rotors underneath these lee waves. The ability of the model to capture the trapped waves is found to depend on the horizontal model resolution. Bora winds are identified as jets emanating from several mountain gaps. The physical mechanism for the gap flow formation is boundary-layer separation controlled by surface friction. Flow separation is more effective over the highest terrain where a broad wake forms downstream with weak winds compared to the mountain gaps where the strong bora flow eventually reattaches to the surface. The strongest gap jet belongs to the Vratnik Pass upstream of the town Senj and forms the primary shear line in the northern Adriatic with a corresponding potential-vorticity (PV) banner. The numerical model reveals several secondary orographic PV banners and embedded PV filaments. The vertical PV distribution exhibits a two-layer structure with PV anomalies at lower (higher) elevations originating from mountain gaps (isolated mountain peaks). Surface friction has a minor direct effect on PV generation but has a major indirect effect in controlling the mechanism for the generation of PV. In a simulation without surface friction the primary PV banner forms as a result of gravity-wave breaking. In the more realistic simulation, however, the primary mechanism for PV generation is flow separation controlled by surface friction. Copyright © 2005 Royal Meteorological Society
Monthly Weather Review, 2004
... REFERENCES. Afanasyev, Ya D., and WR Peltier, 2001a: On breaking internal waves over the sill... more ... REFERENCES. Afanasyev, Ya D., and WR Peltier, 2001a: On breaking internal waves over the sill in Knight Inlet. ... Soc. London, A457, 27992825. Afanasyev, Ya D., and WR Peltier, 2001b: Reply to comment on the paper On breaking internal waves over the sill in Knight Inlet.. ...
Monthly Weather Review, 2005
Monthly Weather Review, 2004
Meteorology and Atmospheric Physics, 2004
Meteorology and Atmospheric Physics, 2000
Summary ¶Intra-mountain summertime precipitation was studied in the Alps in a 40×20 km2 area cen... more Summary ¶Intra-mountain summertime precipitation was studied in the Alps in a 40×20 km2 area centered around Innsbruck, Austria, from June through September 1997. An observational network with a mean separation distance of 9 km and forecasts from the ECMWF model were used to examine the role the strong forcing from the lower boundary plays in creating “hot spots” for the formation of thunderstorms
Meteorology and Atmospheric Physics, 2000
Journal of the Atmospheric Sciences, 2010
Journal of the Atmospheric Sciences, 2000
The influence of the obstacle shape, expressed through the ratio of spanwise to streamwise extens... more The influence of the obstacle shape, expressed through the ratio of spanwise to streamwise extension , on flow over and around a mesoscale mountain is examined numerically. The initial wind U as well as the buoyancy frequency N are constant; the earth's rotation and surface friction are neglected. In these conditions the flow response depends primarily on the nondimensional mountain
Journal of Atmospheric and Oceanic Technology, 2009
Annals of The Rheumatic Diseases, 2011
ObjectiveMicro RNAs (miRNAs) are a new class of regulatory elements. Altered expression of miRNAs... more ObjectiveMicro RNAs (miRNAs) are a new class of regulatory elements. Altered expression of miRNAs has been demonstrated in inflamed joints of patients suffering from rheumatoid arthritis (RA). However, the exact role of miRNAs in the pathogenesis of this disease has not been defined so far.MethodsCollagen induced arthritis (CIA) and K/BxN serum transfer arthritis was induced in wt and miR155−/− mice.
ABSTRACT Precipitation in mountainous regions is an essential process in meteorological research ... more ABSTRACT Precipitation in mountainous regions is an essential process in meteorological research for its strong impact on the hydrological cycle. To support scientists, we present the design of a meteorological application using the ASKALON environment comprising graphical workflow modeling and execution in a Cloud computing environment. We illustrate performance results that demonstrate that, although limited by Amdahl's law, our workflow can gain important speedup when executed in a virtualized Cloud environment with important operational cost reductions. Results from the meteorological research show the usefulness of our model for determining precipitation distribution in the case of two field campaigns over Norway.
2014 IEEE 3rd International Conference on Cloud Networking (CloudNet), 2014
Quarterly Journal of the Royal Meteorological Society, 2008
ABSTRACT This study investigates the onset phase of a strong Adriatic bora windstorm that occurre... more ABSTRACT This study investigates the onset phase of a strong Adriatic bora windstorm that occurred on 4 April 2002. The target area is a gap about 20 km wide embedded in the coastal mountain barrier of the Dinaric Alps that favours strong jet-like winds. Airborne-aerosol back-scatter lidar measurements on board the DLR Falcon research aircraft, together with surface and upper-air observations, are used to verify high-resolution numerical experiments conducted with the mesoscale atmospheric model RAMS and a single-layer shallow-water model (SWM). Especially during the breakthrough phase of the bora, the flow at the gap exit exhibits a complex spatial structure and temporal evolution. On a transect through the centre of the gap, a hydraulic jump forms; this is located close to the coast throughout the night, and starts to propagate downstream in the early morning. On a transect through the edge of the gap, a lee-wave-induced rotor becomes established, due to boundary-layer separation. It starts to propagate downstream about two hours after the jump. This flow evolution implies that the onset of strong winds at the coast occurs several hours earlier downstream of the centre of the gap than downwind of the edge of the gap. Consequently, the wind field in the vicinity of Rijeka airport, located downwind of the gap, is strongly inhomogeneous and transient, and represents a potential hazard to aviation. Measured bora winds at the surface exceed 20 ms−1, and the simulated wind speed in the gap wind layer exceeds 30 ms−1. The simulated turbulent kinetic energy exceeds 10 m2 s−2.RAMS indicates that wave-breaking near a critical level is the dominant mechanism for the generation of the windstorm. Gap jets can be identified downstream of several mountain passes. The simulated wave pattern above the Dinaric Alps, the wave decay with height due to directional wind shear and the strong flow descent on the leeward side of the barrier are supported by measured back-scatter intensities. Basic bora flow features, including gap jets and jumps, are remarkably well reproduced by SWM simulations. The RAMS reference run captures observed flow phenomena and the temporal flow evolution qualitatively well. A cold low-level bias, an overestimated bora inversion strength, and a slightly too-early bora onset are probably related to insufficient turbulent mixing in the boundary layer. The amplitude of trapped gravity waves, the time of the bora breakthrough and the inversion strength are found to be quite sensitive to the turbulence parametrization. Copyright © 2008 Royal Meteorological Society
Quarterly Journal of the Royal Meteorological Society, 2010
Quarterly Journal of the Royal Meteorological Society, 2007
Quarterly Journal of the Royal Meteorological Society, 2007
Quarterly Journal of the Royal Meteorological Society, 2004
Quarterly Journal of the Royal Meteorological Society, 2005
ABSTRACT A detailed analysis of bora winds is presented that were observed on 28 March 2002 in th... more ABSTRACT A detailed analysis of bora winds is presented that were observed on 28 March 2002 in the north-eastern part of the Adriatic Sea. Very high-resolution numerical simulations are compared with airborne, surface, and balloon observations. The key instrument for the verification of the numerical results is an aerosol backscatter lidar on board the DLR Falcon research aircraft. The high spatial resolution of the model and of the observational dataset allows several small-scale aspects of the bora winds to be explored. The study emphasises the great impact of boundary-layer effects including convective mixing and surface friction on the structure of the bora flow.The numerical model reveals that the diurnal cycle of the planetary boundary layer causes a diurnal variation of the gravity-wave amplitude and consequently a variation in the bora strength. The downslope flow is strongest during the night-time when the impinging air mass is stably stratified and exhibits a low-level jet. The bora strength weakens during the daytime due to the evolution of a neutrally stratified convective boundary layer. Lidar observations and simulations both suggest that the observed bora winds are driven by the dynamics of orographic gravity waves. In the deep north-easterly cross-mountain flow steeply amplified but non-breaking gravity waves as well as trapped lee waves are found throughout the troposphere. Vertical separation of the boundary layer over the steep leeward terrain slope prevents the bora flow from reaching the coast. As a result, the flow is kept aloft in a series of at least three unsteady trapped lee waves before it reattaches to the surface over the sea downstream of the mountains. No clear evidence is found for the existence of low-level rotors underneath these lee waves. The ability of the model to capture the trapped waves is found to depend on the horizontal model resolution. Bora winds are identified as jets emanating from several mountain gaps. The physical mechanism for the gap flow formation is boundary-layer separation controlled by surface friction. Flow separation is more effective over the highest terrain where a broad wake forms downstream with weak winds compared to the mountain gaps where the strong bora flow eventually reattaches to the surface. The strongest gap jet belongs to the Vratnik Pass upstream of the town Senj and forms the primary shear line in the northern Adriatic with a corresponding potential-vorticity (PV) banner. The numerical model reveals several secondary orographic PV banners and embedded PV filaments. The vertical PV distribution exhibits a two-layer structure with PV anomalies at lower (higher) elevations originating from mountain gaps (isolated mountain peaks). Surface friction has a minor direct effect on PV generation but has a major indirect effect in controlling the mechanism for the generation of PV. In a simulation without surface friction the primary PV banner forms as a result of gravity-wave breaking. In the more realistic simulation, however, the primary mechanism for PV generation is flow separation controlled by surface friction. Copyright © 2005 Royal Meteorological Society
Monthly Weather Review, 2004
... REFERENCES. Afanasyev, Ya D., and WR Peltier, 2001a: On breaking internal waves over the sill... more ... REFERENCES. Afanasyev, Ya D., and WR Peltier, 2001a: On breaking internal waves over the sill in Knight Inlet. ... Soc. London, A457, 27992825. Afanasyev, Ya D., and WR Peltier, 2001b: Reply to comment on the paper On breaking internal waves over the sill in Knight Inlet.. ...
Monthly Weather Review, 2005
Monthly Weather Review, 2004
Meteorology and Atmospheric Physics, 2004
Meteorology and Atmospheric Physics, 2000
Summary ¶Intra-mountain summertime precipitation was studied in the Alps in a 40×20 km2 area cen... more Summary ¶Intra-mountain summertime precipitation was studied in the Alps in a 40×20 km2 area centered around Innsbruck, Austria, from June through September 1997. An observational network with a mean separation distance of 9 km and forecasts from the ECMWF model were used to examine the role the strong forcing from the lower boundary plays in creating “hot spots” for the formation of thunderstorms
Meteorology and Atmospheric Physics, 2000
Journal of the Atmospheric Sciences, 2010
Journal of the Atmospheric Sciences, 2000
The influence of the obstacle shape, expressed through the ratio of spanwise to streamwise extens... more The influence of the obstacle shape, expressed through the ratio of spanwise to streamwise extension , on flow over and around a mesoscale mountain is examined numerically. The initial wind U as well as the buoyancy frequency N are constant; the earth's rotation and surface friction are neglected. In these conditions the flow response depends primarily on the nondimensional mountain
Journal of Atmospheric and Oceanic Technology, 2009