TITLE

Extreme Helicity and Intense Convective Towers in Hurricane Bonnie

AUTHOR(S)
Molinari, John; Vollaro, David
PUB. DATE
November 2008
SOURCE
Monthly Weather Review;Nov2008, Vol. 136 Issue 11, p4355
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Helicity was calculated in Hurricane Bonnie (1998) using tropospheric-deep dropsonde soundings from the NASA Convection and Moisture Experiment. Large helicity existed downshear of the storm center with respect to the ambient vertical wind shear. It was associated with veering, semicircular hodographs created by strong, vortex-scale, radial-vertical flow induced by the shear. The most extreme values of helicity, among the largest ever reported in the literature, occurred in the vicinity of deep convective cells in the downshear-left quadrant. These cells reached as high as 17.5 km and displayed the temporal and spatial scales of supercells. Convective available potential energy (CAPE) averaged 861 J kg-1 downshear, but only about one-third as large upshear. The soundings nearest the deep cells were evaluated using two empirical supercell parameters that make use of CAPE, helicity, and/or shear. These parameters supported the possible existence of supercells as a consequence of the exceptional helicity combined with moderate but sufficient CAPE. Ambient vertical wind shear exceeded 12 m s-1 for 30 h, yet the hurricane maintained 50 m s-1 maximum winds. It is hypothesized that the long-lived convective cells enabled the storm to resist the negative impact of the shear. Supercells in large-helicity, curved-hodograph environments appear to provide a useful conceptual model for intense convection in the hurricane core. Helicity calculations might also give some insight into the behavior of vortical hot towers, which share some characteristics with supercells.
ACCESSION #
35204815

 

Related Articles

  • MEASURING STORM SURGE WITH AN AIRBORNE WIDE-SWATH RADAR ALTIMETER. Wright, C. Wayne; Walsh, E. J.; Krabill, W. B.; Shaffer, W. A.; Baig, S. R.; Peng, M.; Pietrafesa, L. J.; Garcia, A. W.; Marks, Jr., F. D.; Black, P. G.; Sonntag, J.; Beckley, B. D. // Bulletin of the American Meteorological Society;Oct2009, Vol. 90 Issue 10, p1454 

    The article presents a study on the use of airborne wide-swath radar altimeter technology as an effective tool in measuring storm surge. The researchers studied the storm surge of Hurricane Bonnie on August 26, 1998 to demonstrate the potential benefits of direct airborne measurement. It says...

  • Making the Skies Safer. Allan, Roger // Electronic Design;5/24/2004, Vol. 52 Issue 11, p47 

    This article focuses on the development of the wind-shear detection system developed by researchers at the Airborne Wind-Shear Detection and Avoidance Program of the National Aeronautics and Space Administration (NASA). The development began when alarm over commercial airline crashes related to...

  • Heat, Moisture, and Momentum Budgets of Isolated Deep Midlatitude and Tropical... Schlesinger, Robert // Journal of the Atmospheric Sciences;10/15/99, Vol. 56 Issue 20, p3520 

    Presents information on a study which evaluated the feedback of isolated deep convective clouds over a horizontal scale comparable to one grid cell in typical mesoscale numerical prediction models. Sensitivity of the feedback to modest changes in the initial vertical wind shear intensity and...

  • Distribution of Helicity, CAPE, and Shear in Tropical Cyclones. Molinari, John; Vollaro, David // Journal of the Atmospheric Sciences;Jan2010, Vol. 67 Issue 1, p274 

    The previous study of helicity, CAPE, and shear in Hurricane Bonnie (1998) was extended to all eight tropical cyclones sampled by NASA during the Convection and Moisture Experiments (CAMEX). Storms were categorized as having large or small ambient vertical wind shear, with 10 m s-1 as the...

  • Validation of Satellite-Based Objective Overshooting Cloud-Top Detection Methods Using CloudSat Cloud Profiling Radar Observations. Bedka, Kristopher M.; Dworak, Richard; Brunner, Jason; Feltz, Wayne // Journal of Applied Meteorology & Climatology;Oct2012, Vol. 51 Issue 10, p1811 

    Two satellite infrared-based overshooting convective cloud-top (OT) detection methods have recently been described in the literature: 1) the 11- μm infrared window channel texture (IRW texture) method, which uses IRW channel brightness temperature (BT) spatial gradients and thresholds, and 2)...

  • news and notes.  // Bulletin of the American Meteorological Society;Sep2001, Vol. 82 Issue 9 

    Reports developments related to climatology in the United States as of September 2001. Link between weather and disease; Appropriation of research grants to the National Aeronautics and Space Administration for global carbon cycle studies; Interaction between wind and ocean in the Hawaiian islands.

  • Thick Anvils as Viewed by the TRMM Precipitation Radar. Wei Li; Schumacher, Courtney // Journal of Climate;Mar2011, Vol. 24 Issue 6, p1718 

    This study investigates anvils from thick, nonprecipitating clouds associated with deep convection as observed in the tropics by the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) during the 10-yr period, 1998--2007. Anvils observable by the PR occur, on average, 5 out of...

  • High-Resolution Simulation of Hurricane Bonnie (1998). Part I: The Organization of Eyewall Vertical Motion. Braun, Scott A.; Montgomery, Michael T.; Zhaoxia Pu // Journal of the Atmospheric Sciences;Jan2006, Vol. 63 Issue 1, p19 

    The fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) is used to simulate Hurricane Bonnie at high resolution (2-km spacing) in order to examine how vertical wind shear impacts the distribution of vertical...

  • In-Flight Spectral Characterization and Calibration Stability Estimates for the Clouds and the Earth’s Radiant Energy System (CERES). Matthews, Grant // Journal of Atmospheric & Oceanic Technology;Sep2009, Vol. 26 Issue 9, p1685 

    It is essential to maintain global measurements of the earth radiation budget (ERB) from space, the scattered solar and emitted thermal radiative fluxes leaving the planet. These are required for the purpose of validating current climate model predictions of the planet’s future response...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics