scholarly journals A Tropical Squall Line Observed during TOGA COARE: Extended Comparisons between Simulations and Doppler Radar Data and the Role of Midlevel Wind Shear

2000 ◽  
Vol 128 (11) ◽  
pp. 3709-3730 ◽  
Author(s):  
Thibaut Montmerle ◽  
Jean-Philippe Lafore ◽  
Jean-Luc Redelsperger
Keyword(s):  
Wind Shear ◽  
Doppler Radar ◽  
Radar Data ◽  
Squall Line ◽  
Doppler Radar Data ◽  
Toga Coare

Retrieved Thermodynamic Structure of Hurricane Rita (2005) from Airborne Multi-Doppler Radar Data

2021 ◽  
Author(s):  
Annette M. Boehm ◽  
Michael M. Bell
Keyword(s):  
Wind Shear ◽  
Doppler Radar ◽  
Three Dimensional ◽  
Vertical Wind Shear ◽  
Vertical Motion ◽  
Radar Data ◽  
Vertical Wind ◽  
Vertical Acceleration ◽  
Hurricane Rita ◽  
Doppler Radar Data

AbstractThe newly developed SAMURAI-TR is used to estimate three-dimensional temperature and pressure perturbations in Hurricane Rita on 23 September 2005 from multi-Doppler radar data during the RAINEX field campaign. These are believed to be the first fully three-dimensional gridded thermodynamic observations from a TC. Rita was a major hurricane at this time and was affected by 13 m s−1 deep-layer vertical wind shear. Analysis of the contributions of the kinematic and retrieved thermodynamic fields to different azimuthal wavenumbers suggests the interpretation of eyewall convective forcing within a three-level framework of balanced, quasi-balanced, and unbalanced motions. The axisymmetric, wavenumber-0 structure was approximately in thermal-wind balance, resulting in a large pressure drop and temperature increase toward the center. The wavenumber-1 structure was determined by the interaction of the storm with environmental vertical wind shear resulting in a quasi-balance between shear and shear-induced kinematic and thermo-dynamic perturbations. The observed wavenumber-1 thermodynamic asymmetries corroborate results of previous studies on the response of a vortex tilted by shear, and add new evidence that the vertical motion is nearly hydrostatic on the wavenumber-1 scale. Higher-order wavenumbers were associated with unbalanced motions and convective cells within the eyewall. The unbalanced vertical acceleration was positively correlated with buoyant forcing from thermal perturbations and negatively correlated with perturbation pressure gradients relative to the balanced vortex.

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 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.

An Example of the Use of Mobile, Doppler Radar Data for Tornado Verification

2009 ◽  
Vol 24 (3) ◽  
pp. 884-891 ◽  
Author(s):  
Michael M. French ◽  
Howard B. Bluestein ◽  
Louis J. Wicker ◽  
David C. Dowell ◽  
Matthew R. Kramar
Keyword(s):  
Doppler Radar ◽  
Radar Data ◽  
Squall Line ◽  
Final Conclusion ◽  
Supporting Evidence ◽  
Damage Survey ◽  
Doppler Radar Data ◽  
Straight Line ◽  
Visual Confirmation ◽  
Tornado Damage

Abstract On 16 May 2003, two ground-based, mobile, Doppler radars scanned a potentially tornadic supercell in the Texas Panhandle intermittently from ∼0200 to 0330 UTC. The storm likely was tornadic, but because it was dark, visual confirmation of any tornadoes was not possible. A damage survey was completed after the storm moved through the area. The final conclusion of the damage survey prior to this analysis was that there were two tornadoes near Shamrock, Texas: one that formed prior to 0300 UTC and one that formed at or after 0300 UTC. High-resolution, mobile, Doppler radar data of the supercell were compared with the damage survey information at different times. The location of the first tornado damage path was not consistent with the locations of the low-level circulations in the supercell identified through the mobile, Doppler radar data. The damage within the first path, which consisted mostly of downed trees, may have been caused by straight-line winds in a squall line that moved through the area after the passage of the supercell. The mobile, Doppler radar data did not provide any supporting evidence for the first tornado, but the data did support the existence of the second tornado in Wheeler County on the evening of 15 May 2003. Ground-based, mobile, Doppler radar data may be used as an important tool to help to confirm (or deny) tornado damage reports in situations in which a damage survey cannot be completed or in which the survey does not provide clear evidence as to what phenomenon caused the damage.

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