Search Results

You are looking at 1 - 10 of 136 items for :

  • Bulletin of the American Meteorological Society x
  • All content x
Clear All
Walter A. Petersen, Robert C. Cifelli, Steven A. Rutledge, Brad S. Ferrier, and Bradley F. Smull

Shipborne Doppler radar operations were conducted over the western Pacific warm pool during TOGA COARE using the Massachusetts Institute of Technology and NOAA TOGA C-band Doppler radars. Occasionally the ships carrying these radars were brought to within 50 km of each other to conduct coordinated dual-Doppler scanning. The dual-Doppler operations were considered a test of the logistical and engineering constraints associated with establishing a seagoing dual-Doppler configuration. A very successful dual-Doppler data collection period took place on 9 February 1993 when an oceanic squall line developed, intensified, and propagated through the shipborne dual-Doppler lobes. Later on the same day, NOAA P-3 aircraft sampled a more intense squall line located approximately 400 km to the southeast of the shipborne operations. This study provides an overview of the shipborne dual-Doppler operations, followed by a comparison of the kinematic and precipitation structures of the convective systems sampled by the ships and aircraft. Special emphasis is placed on interpretation of the results relative to the electrical characteristics of each system.

Soundings taken in the vicinity of the ship and aircraft cases exhibited similar thermodynamic instability and shear. Yet Doppler radar analyses suggest that the aircraft case exhibited a larger degree of low-level forcing, stronger updrafts, more precipitation mass in the mixed-phase region of the clouds, and a relatively higher degree of electrification as evidenced by lightning observations. Conversely, convection in the ship case, while producing maximum cloud-top heights of 16 km, was associated with relatively weaker low-level forcing, weaker vertical development above the −5°C level, moderate electric fields at the surface, and little detectable lightning. Differences in the kinematic and precipitation structures were further manifested in composite vertical profiles of mean convective precipitation and vertical motion. When considered relative to the electrical properties of the two systems, the results provide further circumstantial evidence to support previously hypothesized vertical velocity and radar reflectivity thresholds that must be exceeded in the 0° to −20°C regions of tropical cumulonimbi prior to the occurrence of lightning.

Full access
Full access
Carl M. Thomas and David M. Schultz

interpretation of our results, so we stick with more common usage and only plot potential temperature. A strength of potential temperature is that the kinematics and dynamics of fronts are derived in terms of potential temperature. For example, the Sawyer–Eliassen equation for the secondary circulation of fronts is expressed as a function of potential temperature (e.g., Sawyer 1956 ; Eliassen 1962 ; summarized in Eliassen 1990 ). Foundational dynamical studies of fronts—both dry (e.g., Hoskins and

Open access
Nicholas McCarthy, Hamish McGowan, Adrien Guyot, and Andrew Dowdy

The Bushfire Convective Plume Experiment examines the ability of portable, dual-polarized X-band radar to quantify the kinematics of pyroconvection through three case studies. The broad range of scales at which wildfires interact with the atmosphere presents a complex problem for predicting the spread of wildfires and managing their impacts on natural and built environments. The importance of fire–atmosphere coupling has been acknowledged as early as the 1950s in wildfire reconstructions and

Open access
Kenneth P. Bowman, John C. Lin, Andreas Stohl, Roland Draxler, Paul Konopka, Arlyn Andrews, and Dominik Brunner

( Schoeberl and Dessler 2011 ). At a recent conference on Lagrangian methods ( Lin et al. 2011 Lin et al. 2013 ), the participants discussed the evolving requirements for input data for Lagrangian kinematic models. This paper provides a brief review of Lagrangian methods and presents proposals for improving the accuracy of atmospheric Lagrangian models through better access to meteorological analysis and forecast products. LAGRANGIAN METHODS. Model equations. Dynamical models of fluid motion can be

Full access
Timothy J. Wagner, Petra M. Klein, and David D. Turner

transmitting at different channels. These factors combine to put a practical limit on the temporal frequency at which launches can occur, and launches are usually spaced no less than one hour apart so that a balloon can profile a sufficient depth of the atmosphere while allowing enough time to prepare the subsequent sonde. Mobile remote sensing profiling facilities can alleviate these issues by providing detailed analyses of the evolution of the kinematic and thermodynamic structure and stability of the

Open access
Pedro L. Fernández-Cabán, A. Addison Alford, Martin J. Bell, Michael I. Biggerstaff, Gordon D. Carrie, Brian Hirth, Karen Kosiba, Brian M. Phillips, John L. Schroeder, Sean M. Waugh, Eric Williford, Joshua Wurman, and Forrest J. Masters

. Biggerstaff , 2015 : High-resolution dual-Doppler observations of tropical cyclone vortex Rossby waves. 37th Int. Conf. on Radar Meteorology , Amer. Meteor. Soc., 154, https://ams.confex.com/ams/37RADAR/webprogram/Paper275848.html . Alford , A. A. , and M. I. Biggerstaff , 2017 : Mobile radar observations of the kinematics and microphysics of Hurricanes Isaac (2012) and Hermine (2016). 38th Int. Conf. on Radar Meteorology , Amer. Meteor. 12B.3, Soc., https://ams.confex.com/ams/38RADAR

Open access
M. P. Jensen, W. A. Petersen, A. Bansemer, N. Bharadwaj, L. D. Carey, D. J. Cecil, S. M. Collis, A. D. Del Genio, B. Dolan, J. Gerlach, S. E. Giangrande, A. Heymsfield, G. Heymsfield, P. Kollias, T. J. Lang, S. W. Nesbitt, A. Neumann, M. Poellot, S. A. Rutledge, M. Schwaller, A. Tokay, C. R. Williams, D. B. Wolff, S. Xie, and E. J. Zipser

black/red square is the ARM Central Facility, the yellow bullseye is the C-band radar (C-SAPR), and the red bullseye is the N-Pol. The extensive ground instrumentation deployed during MC3E allowed for an integrated analysis of kinematic and microphysical interactions during this event. Figure 11 shows one example of the detailed observations available for storm dynamics studies. In Fig. 11 , radar data were gridded using Cressman weighting to 500-m spacing and multi-Doppler synthesis was

Full access
Patrick Broxton, Peter A. Troch, Mike Schaffner, Carl Unkrich, and David Goodrich

atmosphere is often too cool for there to be significant evaporation. This paper describes a coupled modeling system that considers the localized nature of many flash flood–producing storms, and the importance of snowmelt, and allows high temporal and spatial resolutions required for accurate flash flood prediction. The coupled model (called KINEROS/hsB-SM) combines the Kinematic Erosion and Runoff (KINEROS) overland flow/channel routing model and the hillslope-storage Boussinesq Soil Moisture (hsB

Full access
Bianca Adler, Alexander Gohm, Norbert Kalthoff, Nevio Babić, Ulrich Corsmeier, Manuela Lehner, Mathias W. Rotach, Maren Haid, Piet Markmann, Eckhard Gast, George Tsaknakis, and George Georgoussis

Valley Investigated by Dual-Doppler Lidar Measurements (CROSSINN) project. The addressed research questions, which are formulated in Table 1 , can roughly be divided into three categories: (i) the kinematic flow structure in the valley, (ii) the impact of the flow in the valley on the MoBL characteristics, and (iii) the influence of the synoptic scale flow and surface conditions on the flow structure in the valley. T able 1. Selected research questions. We chose the Inn Valley in Austria—a major

Full access