A Tropical Squall Line Observed during the COPT 81 Experiment in West Africa. Part 1: Kinematic Structure Inferred from Dual-Doppler Radar Data

1987 ◽  
Vol 115 (3) ◽  
pp. 670-694 ◽  
Author(s):  
Michel Chong ◽  
Paul Amayenc ◽  
Georges Scialom ◽  
Jacques Testud
Keyword(s):  
West Africa ◽  
Doppler Radar ◽  
Radar Data ◽  
Squall Line ◽  
Kinematic Structure ◽  
Doppler Radar Data ◽  
Dual Doppler Radar

scholarly journals Multiple-Radar Data Assimilation and Short-Range Quantitative Precipitation Forecasting of a Squall Line Observed during IHOP_2002

2007 ◽  
Vol 135 (10) ◽  
pp. 3381-3404 ◽  
Author(s):  
Qingnong Xiao ◽  
Juanzhen Sun
Keyword(s):  
Data Assimilation ◽  
Radial Velocity ◽  
Doppler Radar ◽  
Radar Data ◽  
Squall Line ◽  
Convective System ◽  
Precipitation Forecasting ◽  
Doppler Radar Data ◽  
The Impact ◽  
Radar Data Assimilation

Abstract The impact of multiple–Doppler radar data assimilation on quantitative precipitation forecasting (QPF) is examined in this study. The newly developed Weather Research and Forecasting (WRF) model Advanced Research WRF (ARW) and its three-dimensional variational data assimilation system (WRF 3DVAR) are used. In this study, multiple–Doppler radar data assimilation is applied in WRF 3DVAR cycling mode to initialize a squall-line convective system on 13 June 2002 during the International H2O Project (IHOP_2002) and the ARW QPF skills are evaluated for the case. Numerical experiments demonstrate that WRF 3DVAR can successfully assimilate Doppler radial velocity and reflectivity from multiple radar sites and extract useful information from the radar data to initiate the squall-line convective system. Assimilation of both radial velocity and reflectivity results in sound analyses that show adjustments in both the dynamical and thermodynamical fields that are consistent with the WRF 3DVAR balance constraint and background error correlation. The cycling of the Doppler radar data from the 12 radar sites at 2100 UTC 12 June and 0000 UTC 13 June produces a more detailed mesoscale structure of the squall-line convection in the model initial conditions at 0000 UTC 13 June. Evaluations of the ARW QPF skills with initialization via Doppler radar data assimilation demonstrate that the more radar data in the temporal and spatial dimensions are assimilated, the more positive is the impact on the QPF skill. Assimilation of both radial velocity and reflectivity has more positive impact on the QPF skill than does assimilation of either radial velocity or reflectivity only. The improvement of the QPF skill with multiple-radar data assimilation is more clearly observed in heavy rainfall than in light rainfall. In addition to the improvement of the QPF skill, the simulated structure of the squall line is also enhanced by the multiple–Doppler radar data assimilation in the WRF 3DVAR cycling experiment. The vertical airflow pattern shows typical characteristics of squall-line convection. The cold pool and its related squall-line convection triggering process are better initiated in the WRF 3DVAR analysis and simulated in the ARW forecast when multiple–Doppler radar data are assimilated.

scholarly journals Shear Instability Wave along a Snowband: Instability Structure, Evolution, and Energetics Derived from Dual-Doppler Radar Data

2005 ◽  
Vol 62 (2) ◽  
pp. 351-370 ◽  
Author(s):  
Masayuki Kawashima ◽  
Yasushi Fujiyoshi
Keyword(s):  
Linear Growth ◽  
Doppler Radar ◽  
Growth Period ◽  
Radar Data ◽  
Shear Instability ◽  
Instability Wave ◽  
Horizontal Shear ◽  
Pressure Work ◽  
Doppler Radar Data ◽  
Dual Doppler Radar

Abstract This article presents a detailed analysis of a meso-γ-scale (∼17 km wavelength) shear instability wave along a snowband using a series of dual-Doppler radar data. The wave developed along a low-level shear line that formed under the strain wind field caused by an adjacent mesoscale vortex. The horizontal wind shear across the line was largest at lower levels, and the eddy-component horizontal winds and the retrieved pressure anomaly showed a bottom-intensified structure as well. The resultant vertical pressure gradient force was found to be responsible for the enhancement of alternating updrafts and downdrafts that were subsequently related to the formation of the reflectivity core/gap structure of the wave. Eddy kinetic energy (EKE) budgets of the evolving disturbance were investigated using time series of retrieved kinematic and thermodynamic data. The wave grew at an approximately constant growth rate for about 40 min from its onset. The EKE in this quasi-linear growth period was primarily generated by the horizontal shear that decreased with height. The pressure work was found to remove about two-thirds of this generation in the layer below 1 km, while in the upper layer it was constructive to EKE generation and comparable to the generation of EKE by horizontal shear. These results indicate that the source of EKE was basically located at low levels and the energy was transported upward mainly by the pressure work. After the quasi-linear growth period, horizontal shear generation rapidly decreased and EKE peaked. The buoyancy generation of EKE was small but positive in the quasi-linear growth period, then became negative because of the development of thermally indirect circulations.

The Kinematic Structure of Hurricane Gloria (1985) Determined from Nested Analyses of Dropwindsonde and Doppler Radar Data

1993 ◽  
Vol 121 (9) ◽  
pp. 2433-2451 ◽  
Author(s):  
James L. Franklin ◽  
Stephen J. Lord ◽  
Steven E. Feuer ◽  
Frank D. Marks
Keyword(s):  
Doppler Radar ◽  
Radar Data ◽  
Kinematic Structure ◽  
Doppler Radar Data

scholarly journals An Automatic Recognition Method for Airflow Field Structures of Convective Systems Based on Single Doppler Radar Data

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 142
Author(s):  
Ping Wang ◽  
Kai Gu ◽  
Jinyi Hou ◽  
Bingjie Dou
Keyword(s):  
Doppler Radar ◽  
Three Dimensional ◽  
Radar Data ◽  
Automatic Recognition ◽  
Squall Line ◽  
Appearance Model ◽  
Recognition Method ◽  
Convective Systems ◽  
Doppler Radar Data ◽  
Airflow Field

Airflow structures within convective systems are important predictors of damaging convective disasters. To automatically recognize different kinds of airflow structures (the convergence, divergence, cyclonic rotation, and anticyclonic rotation) within convective systems, an airflow structure recognition method is proposed, in this paper, based on a regular hexagonal template. On the basis of single Doppler radar data, the template is designed according to the appearance model of airflows in radial velocity maps. The proposed method is able to output types and intensities of airflow structures within convective systems. In addition, the outputs of the proposed method are integrated into a projection map of the airflow field structure types and intensities (PMAFSTI), which is developed in this work to visualize three-dimensional airflow structures within convective cells. The proposed airflow structure automatic recognition method and the PMAFSTI were tested using three typical cases. Results of the tests suggest the following: (1) At different evolution stages of the convective systems, e.g., growth, split, and dissipation, the three-dimensional distribution of the airflow fields within convective systems could be clearly observed through the PMAFSTI and (2) on the basis of recognizing the structures of the airflow field, the complex airflow field, such as a squall line, could be further divided into several small parts making the analysis of convective systems more scientific and elaborate.

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