GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    An Idealized Physical Model for the Severe Convective Storm Environmental Sounding
    American Meteorological Society ; 2021
    In:  Journal of the Atmospheric Sciences Vol. 78, No. 2 ( 2021-02), p. 653-670
    Details
    In: Journal of the Atmospheric Sciences, American Meteorological Society, Vol. 78, No. 2 ( 2021-02), p. 653-670
    Abstract: This work develops a theoretical model for steady thermodynamic and kinematic profiles for severe convective storm environments, building off the two-layer static energy framework developed in work by Agard and Emanuel. The model is phrased in terms of static energy, and it allows for independent variation of the boundary layer and free troposphere separated by a capping inversion. An algorithm is presented to apply the model to generate a sounding for numerical simulations of severe convective storms, and the model is compared and contrasted with that of Weisman and Klemp. The model is then fit to a case-study sounding associated with the 3 May 1999 tornado outbreak, and its potential utility is demonstrated via idealized numerical simulation experiments. A long-lived supercell is successfully simulated with the historical sounding but not the analogous theoretical sounding. Two types of example experiments are then performed that do simulate a long-lived supercell: 1) a semitheoretical experiment in which a portion of the theoretical sounding is modified to match the real sounding (low-level moisture); 2) a fully theoretical experiment in which a model physical parameter is modified (free-tropospheric relative humidity). Overall, the construction of this minimal model is flexible and amenable to additional modifications as needed. The model offers a novel framework that may be useful for testing how severe convective storms depend on the vertical structure of the hydrostatic environment, as well as for linking variability in these environments to the physical processes that produce them within the climate system.
    Type of Medium: Online Resource
    ISSN: 0022-4928 , 1520-0469
    URL: Article
    DOI: 10.1175/JAS-D-20-0120.1
    RVK:
    UA 4800
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2021
    detail.hit.zdb_id: 218351-1
    detail.hit.zdb_id: 2025890-2
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Climatology of Severe Local Storm Environments and Synoptic-Scale Features over North America in ERA5 Reanalysis and CAM6 Simulation
    American Meteorological Society ; 2020
    In:  Journal of Climate Vol. 33, No. 19 ( 2020-10-01), p. 8339-8365
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 33, No. 19 ( 2020-10-01), p. 8339-8365
    Abstract: Severe local storm (SLS) activity is known to occur within specific thermodynamic and kinematic environments. These environments are commonly associated with key synoptic-scale features—including southerly Great Plains low-level jets, drylines, elevated mixed layers, and extratropical cyclones—that link the large-scale climate to SLS environments. This work analyzes spatiotemporal distributions of both extreme values of SLS environmental parameters and synoptic-scale features in the ERA5 reanalysis and in the Community Atmosphere Model, version 6 (CAM6), historical simulation during 1980–2014 over North America. Compared to radiosondes, ERA5 successfully reproduces SLS environments, with strong spatiotemporal correlations and low biases, especially over the Great Plains. Both ERA5 and CAM6 reproduce the climatology of SLS environments over the central United States as well as its strong seasonal and diurnal cycles. ERA5 and CAM6 also reproduce the climatological occurrence of the synoptic-scale features, with the distribution pattern similar to that of SLS environments. Compared to ERA5, CAM6 exhibits a high bias in convective available potential energy over the eastern United States primarily due to a high bias in surface moisture and, to a lesser extent, storm-relative helicity due to enhanced low-level winds. Composite analysis indicates consistent synoptic anomaly patterns favorable for significant SLS environments over much of the eastern half of the United States in both ERA5 and CAM6, though the pattern differs for the southeastern United States. Overall, our results indicate that both ERA5 and CAM6 are capable of reproducing SLS environments as well as the synoptic-scale features and transient events that generate them.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    URL: Article
    DOI: 10.1175/JCLI-D-19-0986.1
    DOI: 10.1175/JCLI-D-19-0986.s1
    RVK:
    UA 4548
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2020
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    The Role of Elevated Terrain and the Gulf of Mexico in the Production of Severe Local Storm Environments over North America
    American Meteorological Society ; 2021
    In:  Journal of Climate Vol. 34, No. 19 ( 2021-10), p. 7799-7819
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 34, No. 19 ( 2021-10), p. 7799-7819
    Abstract: The prevailing conceptual model for the production of severe local storm (SLS) environments over North America asserts that upstream elevated terrain and the Gulf of Mexico are both essential to their formation. This work tests this hypothesis using two prescribed-ocean climate model experiments with North American topography removed or the Gulf of Mexico converted to land and analyzes how SLS environments and associated synoptic-scale drivers (southerly Great Plains low-level jets, drylines, elevated mixed layers, and extratropical cyclones) change relative to a control historical run. Overall, SLS environments depend strongly on upstream elevated terrain but more weakly on the Gulf of Mexico. Removing elevated terrain substantially reduces SLS environments especially over the continental interior due to broad reductions in both thermodynamic instability and vertical wind shear, leaving a more zonally uniform residual distribution that is maximized near the Gulf coast and decays toward the continental interior. This response is associated with a strong reduction in synoptic-scale drivers and a cooler and drier mean-state atmosphere. Replacing the Gulf of Mexico with land modestly reduces SLS environments over the Great Plains (driven primarily thermodynamically) and increases them over the eastern United States (driven primarily kinematically), shifting the primary local maximum eastward into Illinois; it also eliminates the secondary, smaller local maximum over southern Texas. This response is associated with modest changes in synoptic-scale drivers and a warmer and drier lower troposphere. These experiments provide insight into the role of elevated terrain and the Gulf of Mexico in modifying the spatial distribution and seasonality of SLS environments.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    URL: Article
    DOI: 10.1175/JCLI-D-20-0607.1
    DOI: 10.1175/JCLI-D-20-0607.s1
    RVK:
    UA 4548
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2021
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Simulations of Polarimetric, X-Band Radar Signatures in Supercells. Part I: Description of Experiment and Simulated ρhv Rings
    American Meteorological Society ; 2017
    In:  Journal of Applied Meteorology and Climatology Vol. 56, No. 7 ( 2017-07), p. 1977-1999
    Details
    In: Journal of Applied Meteorology and Climatology, American Meteorological Society, Vol. 56, No. 7 ( 2017-07), p. 1977-1999
    Abstract: With the development of multimoment bulk microphysical schemes and polarimetric radar forward operators, one can better examine convective storms simulated in high-resolution numerical models from a simulated polarimetric radar perspective. Subsequently, relationships between observable and unobservable quantities can be examined that may provide useful information about storm intensity and organization that otherwise would be difficult to obtain. This paper, Part I of a two-part sequence, describes the bulk microphysics scheme, polarimetric radar forward operator, and numerical model configuration used to simulate supercells in eight idealized, horizontally homogenous environments with different wind profiles. The microphysical structure and evolution of copolar cross-correlation coefficient (ρ hv ) rings associated with simulated supercells are examined in Part I, whereas Part II examines Z DR columns, Z DR rings, and K DP columns. In both papers, some systematic differences between the signature seen at X and S bands are discussed. The presence of hail is found to affect ρ hv much more at X band than at S band (and is found to affect Z DR more at S band than at X band), which corroborates observations. The ρ hv half ring is found to be associated with the presence of large, sometimes wet, hail aloft, with an ~20-min time lag between increases in the size of the ρ hv ring aloft and the occurrence of a large amount of hail near the ground in some simulations.
    Type of Medium: Online Resource
    ISSN: 1558-8424 , 1558-8432
    URL: Article
    DOI: 10.1175/JAMC-D-16-0138.1
    RVK:
    UA 4547
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2017
    detail.hit.zdb_id: 2227779-1
    detail.hit.zdb_id: 2227759-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Simulations of Polarimetric, X-Band Radar Signatures in Supercells. Part II: ZDR Columns and Rings and KDP Columns
    American Meteorological Society ; 2017
    In:  Journal of Applied Meteorology and Climatology Vol. 56, No. 7 ( 2017-07), p. 2001-2026
    Details
    In: Journal of Applied Meteorology and Climatology, American Meteorological Society, Vol. 56, No. 7 ( 2017-07), p. 2001-2026
    Abstract: A high-resolution numerical model and polarimetric forward operator allow one to examine simulated convective storms from the perspective of observable polarimetric radar quantities, enabling a better comparison of modeled and observed deep moist convection. Part I of this two-part study described the model and forward operator used for all simulations and examined the structure and evolution of rings of reduced copolar cross-correlation coefficient (i.e., ρ hv rings). The microphysical structure of upward extensions of enhanced differential reflectivity ( Z DR columns and Z DR rings) and enhanced specific differential phase ( K DP columns) near and within the updrafts of convective storms serve as the focus of this paper. In general, simulated Z DR columns are located immediately west of the midlevel updraft maximum and are associated with rainwater lofted above the 0°C level and wet hail/graupel, whereas Z DR rings are associated with wet hail located near and immediately east of the midlevel updraft maximum. The deepest areas of Z DR 〉 1 dB aloft are associated with supercells in the highest shear environments and those that have the most intense updrafts; the upper extent of the Z DR signatures is found to be positively correlated with the amount and mean-mass diameter of large hail aloft likely as a by-product of the shared correlations with updraft intensity and wind shear. Large quantities of rain compose the K DP columns, with the size and intensity of the updrafts directly proportional to the size and depth of the K DP columns.
    Type of Medium: Online Resource
    ISSN: 1558-8424 , 1558-8432
    URL: Article
    DOI: 10.1175/JAMC-D-16-0139.1
    RVK:
    UA 4547
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2017
    detail.hit.zdb_id: 2227779-1
    detail.hit.zdb_id: 2227759-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    Low-Level Polarimetric Radar Signatures in EnKF Analyses and Forecasts of the May 8, 2003 Oklahoma City Tornadic Supercell: Impact of Multimoment Microphysics and Comparisons with Observation
    Hindawi Limited ; 2013
    In:  Advances in Meteorology Vol. 2013 ( 2013), p. 1-13
    Details
    In: Advances in Meteorology, Hindawi Limited, Vol. 2013 ( 2013), p. 1-13
    Abstract: The impact of increasing the number of predicted moments in a multimoment bulk microphysics scheme is investigated using ensemble Kalman filter analyses and forecasts of the May 8, 2003 Oklahoma City tornadic supercell storm and the analyses are validated using dual-polarization radar observations. The triple-moment version of the microphysics scheme exhibits the best performance, relative to the single- and double-moment versions, in reproducing the low- Z DR hail core and high- Z DR arc, as well as an improved probabilistic track forecast of the mesocyclone. A comparison of the impact of the improved microphysical scheme on probabilistic forecasts of the mesocyclone track with the observed tornado track is also discussed.
    Type of Medium: Online Resource
    ISSN: 1687-9309 , 1687-9317
    URL: Article
    DOI: 10.1155/2013/818394
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2013
    detail.hit.zdb_id: 2486777-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    A Method to Control the Environmental Wind Profile in Idealized Simulations of Deep Convection with Surface Friction
    American Meteorological Society ; 2019
    In:  Monthly Weather Review Vol. 147, No. 11 ( 2019-11-01), p. 3935-3954
    Details
    In: Monthly Weather Review, American Meteorological Society, Vol. 147, No. 11 ( 2019-11-01), p. 3935-3954
    Abstract: In idealized, horizontally homogeneous, cloud model simulations of convective storms, the action of surface friction can substantially modify the near-ground environmental wind profile over time owing to the lack of a large-scale pressure gradient force to balance the frictional force together with the Coriolis force. This situation is undesirable for many applications where the impact of an unchanging environmental low-level wind shear on the simulated storm behavior is the focus of investigation, as it introduces additional variability in the experiment and accordingly complicates interpretation of the results. Partly for this reason, many researchers have opted to perform simulations with free-slip lower boundary conditions, which with appropriate boundary conditions allows for more precise control of the large-scale environmental wind profile. Yet, some recent studies have advocated important roles of surface friction in storm dynamics. Here, a simple method is introduced to effectively maintain any chosen environmental wind profile in idealized storm simulations in the presence of surface friction and both resolved and subgrid-scale turbulent mixing. The method is demonstrated through comparisons of simulations of a tornadic supercell with and without surface friction and with or without invoking the new method. The method is compared with similar techniques in the literature and potential extensions and other applications are discussed.
    Type of Medium: Online Resource
    ISSN: 0027-0644 , 1520-0493
    URL: Article
    DOI: 10.1175/MWR-D-18-0462.1
    RVK:
    RA 1000
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2019
    detail.hit.zdb_id: 2033056-X
    detail.hit.zdb_id: 202616-8
    SSG: 14
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 8
    Online Resource
    Online Resource
    Bin-Emulating Hail Melting in Three-Moment Bulk Microphysics
    American Meteorological Society ; 2020
    In:  Journal of the Atmospheric Sciences Vol. 77, No. 10 ( 2020-10-01), p. 3361-3385
    Details
    In: Journal of the Atmospheric Sciences, American Meteorological Society, Vol. 77, No. 10 ( 2020-10-01), p. 3361-3385
    Abstract: A three-moment bulk microphysics scheme is modified to treat melting in a size-dependent manner that emulates results from a spectral bin scheme. The three-moment bulk framework allows the distribution shape to change and accommodate some direct effects of melting on both the hail and raindrop size distributions. Reflectivity changes and shed raindrop sizes are calculated over discrete size ranges of the hail particle spectrum. Smaller ice particles are treated as melting into drops of the same mass, whereas large particles shed drops as they melt. As small ice particles are lost, the size spectrum naturally becomes narrower and the mean size of small hail can increase. Large hail with a narrow spectrum, however, can decrease in size from melting. A substantial effect is seen on the rain median volume diameter when small drops are shed from large melting hail. The NSSL bulk scheme is compared with bin microphysics in steady-state hail shafts and in a supercell storm case. It is also shown that melting (or any substantial removal of mass) induces gravitational size sorting in bulk microphysics to increase hail size despite the design of the process rates to maintain the mean size of the melting ice. This unintended side effect can be a correct behavior for small hail, but not for large hail with a narrow distribution, when mean hail size should decrease by melting.
    Type of Medium: Online Resource
    ISSN: 0022-4928 , 1520-0469
    URL: Article
    DOI: 10.1175/JAS-D-19-0268.1
    RVK:
    UA 4800
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2020
    detail.hit.zdb_id: 218351-1
    detail.hit.zdb_id: 2025890-2
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 9
    Online Resource
    Online Resource
    Impact of the Environmental Low-Level Wind Profile on Ensemble Forecasts of the 4 May 2007 Greensburg, Kansas, Tornadic Storm and Associated Mesocyclones
    American Meteorological Society ; 2012
    In:  Monthly Weather Review Vol. 140, No. 2 ( 2012-02), p. 696-716
    Details
    In: Monthly Weather Review, American Meteorological Society, Vol. 140, No. 2 ( 2012-02), p. 696-716
    Abstract: The early tornadic phase of the Greensburg, Kansas, supercell on the evening of 4 May 2007 is simulated using a set of storm-scale (1-km horizontal grid spacing) 30-member ensemble Kalman filter (EnKF) data assimilation and forecast experiments. The Next Generation Weather Radar (NEXRAD) level-II radar data from the Dodge City, Kansas (KDDC), Weather Surveillance Radar-1988 Doppler (WSR-88D) are assimilated into the National Severe Storms Laboratory (NSSL) Collaborative Model for Multiscale Atmospheric Simulation (COMMAS). The initially horizontally homogeneous environments are initialized from one of three reconstructed soundings representative of the early tornadic phase of the storm, when a low-level jet (LLJ) was intensifying. To isolate the impact of the low-level wind profile, 0–3.5-km AGL wind profiles from Vance Air Force Base, Oklahoma (KVNX), WSR-88D velocity-azimuth display (VAD) analyses at 0130, 0200, and 0230 UTC are used. A sophisticated, double-moment bulk ice microphysics scheme is employed. For each of the three soundings, ensemble forecast experiments are initiated from EnKF analyses at various times prior to and shortly after the genesis of the Greensburg tornado (0200 UTC). Probabilistic forecasts of the mesocyclone-scale circulation(s) are generated and compared to the observed Greensburg tornado track. Probabilistic measures of significant rotation and observation-space diagnostic statistics are also calculated. It is shown that, in general, the track of the Greensburg tornado is well predicted, and forecasts improve as forecast lead time decreases. Significant variability is also seen across the experiments using different VAD wind profiles. Implications of these results regarding the choice of initial mesoscale environment, as well as for the “Warn-on-Forecast” paradigm for probabilistic numerical prediction of severe thunderstorms and tornadoes, are discussed.
    Type of Medium: Online Resource
    ISSN: 0027-0644 , 1520-0493
    URL: Article
    DOI: 10.1175/MWR-D-11-00008.1
    RVK:
    RA 1000
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2012
    detail.hit.zdb_id: 2033056-X
    detail.hit.zdb_id: 202616-8
    SSG: 14
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 10
    Online Resource
    Online Resource
    A Triple-Moment Representation of Ice in the Predicted Particle Properties (P3) Microphysics Scheme
    American Meteorological Society ; 2021
    In:  Journal of the Atmospheric Sciences Vol. 78, No. 2 ( 2021-02), p. 439-458
    Details
    In: Journal of the Atmospheric Sciences, American Meteorological Society, Vol. 78, No. 2 ( 2021-02), p. 439-458
    Abstract: In the original Predicted Particle Properties (P3) bulk microphysics scheme, all ice-phase hydrometeors are represented by one or more “free” ice categories, where the physical properties evolve smoothly through changes to the four prognostic variables (per category), and with a two-moment representation of the particle size distribution. As such, the spectral dispersion cannot evolve independently, which thus results in limitations in representation of ice—in particular, hail—due to necessary constraints in the scheme to prevent excessive gravitational size sorting. To overcome this, P3 has been modified to include a three-moment representation of the size distribution of each ice category through the addition of a fifth prognostic variable, the sixth moment of the size distribution. The details of the three-moment ice parameterization in P3 are provided. The behavior of the modified scheme, with the single-ice-category configuration, is illustrated through simulations in a simple 1D kinematic model framework as well as with near large-eddy-resolving (250-m grid spacing) 3D simulations of a hail-producing supercell. It is shown that the three-moment ice configuration controls size sorting in a physically based way and leads to an improved capacity to simulate large, heavily rimed ice (hail), including mean and maximum sizes and reflectivity, and thus an overall improvement in the representation of ice-phase particles in the P3 scheme.
    Type of Medium: Online Resource
    ISSN: 0022-4928 , 1520-0469
    URL: Article
    DOI: 10.1175/JAS-D-20-0084.1
    RVK:
    UA 4800
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2021
    detail.hit.zdb_id: 218351-1
    detail.hit.zdb_id: 2025890-2
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...