ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Insights into Hydrometeorological Factors Constraining Flood Prediction Skill during the May and October 2015 Texas Hill Country Flood Events (2018)
    American Meteorological Society
    Details
    Publication Date: 2018-08-01
    Description: This study evaluates the May and October 2015 flood prediction skill of a physically based model resembling the U.S. National Water Model (NWM) over the Texas Hill Country. It also investigates hydrometeorological factors that contributed to a record flood along the Blanco River at Wimberley (WMBT2) in May 2015. Using two radar-based quantitative precipitation estimation (QPE) products—Stage IV and Multi-Radar Multi-Sensor (MRMS)—it is shown that the event precipitation accuracy dominates the prediction skill, where the finer-resolution MRMS QPE mainly benefits basins with small drainage areas. Overall, the model exhibits good performance at gauges with fast flood response from causative rainfall and gauges that are not forecast points in the National Weather Service’s Advanced Hydrometeorological Prediction System, showing great promise for forecasts, warnings, and emergency response. However, the model suffers from poor prediction skill over regions without rapid flood response and regions with human-altered flows, suggesting the need to revisit the channel routing algorithm and incorporate modules to represent human alterations. Two contrasting flood events at WMBT2 with similar meteorological characteristics are examined in greater detail, revealing that the location of intense rainfall combined with land physiographic features are key to the flood response differences. Model sensitivity tests further show the record flood peak could be better obtained by tuning the deep-layer soil wetness and the flow velocity field in the river network, which offers hydrometeorological insights into the causes and the complex nature of such a flood and why the model struggles to predict the record flood peak.
    Print ISSN: 1525-755X
    Electronic ISSN: 1525-7541
    Topics: Geography , Geosciences , Physics
    Published by American Meteorological Society
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Drop-Size Distribution Variations Associated with Different Storm Types in Southeast Texas (2019)
    Molecular Diversity Preservation International
    Details
    Publication Date: 2019-12-20
    Description: Drop-size distributions (DSDs) provide important microphysical information about rainfall and are used in rainfall estimates from radar. This study utilizes a four-year DSD dataset of 163 rain events obtained using a Joss–Waldvogel impact disdrometer located in southeast Texas. A seasonal comparison of the DSD data shows that small (~1 mm diameter) drops occur more frequently in winter and fall, whereas summer and spring months see an increase in the relative frequency of medium and large (~〉2 mm diameter) drops, with notable interannual variability in all seasons. Each rain event is classified by dynamic forcing and radar precipitation structure to more directly link environmental and storm organization properties to storm microphysics. Cold fronts and upper-level disturbances account for 80% of the rain events, whereas warm fronts, weakly forced situations, and tropical cyclones comprise the other 20%. Warm frontal storms and upper-level disturbances have smaller drops compared to the climatological DSD for southeast Texas, whereas the more dynamically vigorous cold fronts and weakly forced environments have larger drops. Tropical cyclones generally produce smaller drops than the climatology, but their DSD anomalies are sensitive to what part of the storm is sampled. Regardless of dynamic forcing, storms with precipitation structures that are mostly deep convective or stratiform rain formed from deep convection have larger drops, whereas stratiform rain formed from non-deep convection has smaller drops. Reflectivity-rain rate (Z-R) relationships that account for dynamic forcing and precipitation structures improve rainfall estimates compared to climatological Z-R relationships despite a wide spread in Z-R relationships by storm.
    Electronic ISSN: 2073-4433
    Topics: Geosciences
    Published by Molecular Diversity Preservation International
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Assessing the Applicability of the Tropical Convective–Stratiform Paradigm in the Extratropics Using Radar Divergence Profiles (2014)
    American Meteorological Society
    Details
    Publication Date: 2014-08-28
    Description: Long-term radar observations from a subtropical location in southeastern Texas are used to examine the impact of storm systems with tropical or extratropical characteristics on the large-scale circulation. Climatological vertical profiles of the horizontal wind divergence are analyzed for four distinct storm classifications: cold frontal (CF), warm frontal (WF), deep convective upper-level disturbance (DC-ULD), and nondeep convective upper-level disturbances (NC-ULD). DC-ULD systems are characterized by weakly baroclinic or equivalent barotropic environments that are more tropical in nature, while the remaining classifications are representative of common midlatitude systems with varying degrees of baroclinicity. DC-ULD systems are shown to have the highest levels of nondivergence (LND) and implied diabatic heating maxima near 6 km, whereas the remaining baroclinic storm classifications have LND altitudes that are about 0.5–1 km lower. Analyses of climatological mean divergence profiles are also separated by rain regions that are primarily convective, stratiform, or indeterminate. Convective–stratiform separations reveal similar divergence characteristics to those observed in the tropics in previous studies, with higher altitudes of implied heating in stratiform rain regions, suggesting that the convective–stratiform paradigm outlined in previous studies is applicable in the midlatitudes. Divergence profiles that cannot be classified as primarily convective or stratiform are typically characterized by large regions of stratiform rain with areas of embedded convection of shallow to moderate extent (i.e., echo tops
    Print ISSN: 0894-8755
    Electronic ISSN: 1520-0442
    Topics: Geography , Geosciences , Physics
    Published by American Meteorological Society
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Modeled and Observed Variations in Storm Divergence and Stratiform Rain Production in Southeastern Texas (2012)
    American Meteorological Society
    Details
    Publication Date: 2012-03-30
    Description: Storm divergence profiles observed by an S-band Doppler radar are compared to ensemble simulations of 10 disparate precipitating systems occurring in warm-season, weakly baroclinic, and strongly baroclinic environments in southeastern Texas. Eight triply nested mesoscale model simulations are conducted for each case using single- and double-moment microphysics with four convective treatments (i.e., two convective parameterizations and explicit versus parameterized convection at 9 km). Observed and simulated radar reflectivities are objectively separated into convective, stratiform, and nonprecipitating anvil columns and comparisons are made between ensemble mean echo coverages and levels of nondivergence (LNDs). In both the model and observations, storms occurring in less baroclinic environments have more convective rain area, less stratiform rain area, and more elevated divergence profiles. The model ensemble and observations agree best for well-organized leading-line trailing-stratiform systems. Excessive convective area fractions are simulated for several less-organized cases, especially those whose ensemble mean LNDs are about 1–2 km more elevated than observed. Simulations parameterizing convection on the intermediate grid produced less-elevated divergence profiles with smaller magnitudes compared to their explicit counterparts. In one warm-season case, utilizing double-moment microphysics when parameterizing convection on both outer grids generated lower LNDs associated with variations in convective intensity and depth, detraining less ice to anvil and stratiform regions at midlevels relative to its single-moment counterpart. Similarly, mesoscale convective vortex simulations employing an ensemble-based versus a single-closure convective parameterization on both outer grids produced the least-elevated heating structures (closer to observed), resulting in the weakest midlevel vortices.
    Print ISSN: 0022-4928
    Electronic ISSN: 1520-0469
    Topics: Geography , Geosciences , Physics
    Published by American Meteorological Society
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Baroclinicity Influences on Storm Divergence and Stratiform Rain: Subtropical Upper-Level Disturbances (2009)
    American Meteorological Society
    Details
    Publication Date: 2009-04-01
    Description: Divergence structures associated with the spectrum of precipitating systems in the subtropics and midlatitudes are not well documented. A mesoscale model is used to quantify the relative importance different baroclinic environments have on divergence profiles for storms primarily caused by upper-level disturbances in southeastern Texas, a subtropical region. The divergence profiles simulated for a subset of the modeled storms are consistent with those calculated from an S-band Doppler radar. Realistic convective and stratiform divergence signals are also generated when applying a two-dimensional convective–stratiform separation algorithm to reflectivities derived from the mesoscale model, although the model appears to underestimate stratiform rain area. Divergence profiles from the modeled precipitating systems vary in magnitude and structure across the wide range of baroclinicities common in southeastern Texas. Barotropic storms more characteristic of the tropics generate the most elevated divergence (and thus diabatic heating) structures with the largest magnitudes. In addition, stratiform rain regions in barotropic storms contain thicker, more elevated midlevel convergence signatures than more baroclinic storms. As the degree of baroclinicity increases, stratiform area fractions generally increase while the levels of nondivergence (LNDs) decrease. However, some weakly baroclinic storms contain stratiform area fractions and/or divergence profiles with magnitudes and LNDs that are similar to barotropic storms, despite having lower tropopause heights and less deep convection. Additional convection forms after the passage of barotropic and weakly baroclinic storms that contain elevated divergence signatures, circumstantially suggesting that heating at upper levels may cause diabatic feedbacks that help to drive regions of persistent convection in the subtropics.
    Print ISSN: 0027-0644
    Electronic ISSN: 1520-0493
    Topics: Geography , Geosciences , Physics
    Published by American Meteorological Society
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...