Simulations of the concept of using a small nonscanning Doppler radar for wind shear detection

AbstractHurricane Matthew (2016) was observed by ground-based polarimetric radars in Miami (KAMX), Melbourne (KMLB), and Jacksonville (KJAX) and a NOAA P3 airborne tail Doppler radar near the coast of the southeastern United States during an eyewall replacement cycle (ERC). The radar observations indicate that Matthew’s primary eyewall was replaced with a weaker outer eyewall, but unlike a classic ERC, Matthew did not reintensify after the inner eyewall disappeared. Triple Doppler analysis was calculated from the NOAA P3 airborne fore and aft radar scanning combined with the KAMX radar data during the period of secondary eyewall intensification and inner eyewall weakening from 19 UTC 6 October to 00 UTC 7 October. Four flight passes of the P3 aircraft show the evolution of the reflectivity, tangential winds, and secondary circulation as the outer eyewall became well-established. Further evolution of the ERC is analyzed from the ground-based single Doppler radar observations for 35 hours with high temporal resolution at a 5-minute interval from 19 UTC 6 October to 00 UTC 8 October using the Generalized Velocity Track Display (GVTD) technique. The single-Doppler analyses indicate that the inner eyewall decayed a few hours after the P3 flight, while the outer eyewall contracted but did not reintensify and the asymmetries increased episodically. The analysis suggests that the ERC process was influenced by a complex combination of environmental vertical wind shear, an evolving axisymmetric secondary circulation, and an asymmetric vortex Rossby wave damping mechanism that promoted vortex resiliency despite increasing shear.

Download Full-text

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

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-20-0195.1 ◽

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.

Download Full-text

Performance Evaluation of a Doppler Radar System for Wind Shear Detection

10.23919/acc.1990.4790837 ◽

1990 ◽

Cited By ~ 3

Author(s):

Camille S. Khalaf ◽

Joseph L. Hibey ◽

Leo D. Staton

Keyword(s):

Performance Evaluation ◽

Wind Shear ◽

Doppler Radar ◽

Radar System

Download Full-text

Radar Kinematic Information as a Surrogate for Isentropes in Stratiform Precipitation Systems

Monthly Weather Review ◽

10.1175/mwr-d-16-0470.1 ◽

2017 ◽

Vol 145 (9) ◽

pp. 3763-3774 ◽

Cited By ~ 1

Author(s):

Bart Geerts ◽

Jordan I. Christian

Keyword(s):

Wind Shear ◽

Doppler Radar ◽

Potential Temperature ◽

Vertical Gradient ◽

Horizontal Wind ◽

Model Output ◽

Vertical Resolution ◽

Equivalent Potential ◽

Stratiform Precipitation ◽

Kinematic Information

Abstract This study illustrates that dual-Doppler-derived wind shear (vertical gradient of the horizontal wind) in stratiform, nonturbulent flow is structured in long, thin striations. The reason this has not been documented before is that scanning ground-based radars have inadequate vertical resolution, deteriorating with range. Here data from an airborne radar with a fine, range-independent vertical resolution are used. A comparison of the radar-derived wind shear with model output of isentropes in vertical transects in the comma head of two frontal disturbances suggests that the wind shear layers describe material surfaces. Model output itself further confirms the alignment of isentropes with wind shear in vertical transects. Thus, Doppler-radar-derived wind shear (a kinematic conserved variable) may serve as a suitable proxy for thermodynamic conserved variables such as equivalent potential temperature in stratiform precipitation. Furthermore, the presence of shear striations in vertical transects can be used as a marker for nonturbulent flow, and their persistence as an indicator of limited dispersion in such flow.

Download Full-text

A Velocity Dealiasing Scheme Based on Minimization of Velocity Differences between Regions

Advances in Meteorology ◽

10.1155/2020/6157636 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Yue Yuan ◽

Ping Wang ◽

Di Wang ◽

Junzhi Shi

Keyword(s):

Radial Velocity ◽

Wind Shear ◽

Doppler Radar ◽

Heavy Precipitation ◽

Probability Of Detection ◽

Strong Wind ◽

Velocity Data ◽

Step Velocity ◽

Noise Data ◽

Radial Velocity Data

The velocity dealiasing is an essential work of automatic weather phenomenon identification, nowcasting, and disaster monitoring based on radial velocity data. The noise data, strong wind shear, and isolated echo region in the Doppler radar radial velocity data severely interfere with the velocity dealiasing algorithm. This paper proposes a two-step velocity dealiasing algorithm based on the minimization of velocity differences between regions to solve this problem. The first step is to correct aliased velocities by minimizing the sum of gradients in every region to eliminate abnormal velocity gradients between points. The interference of noise data and strong wind shear can be reduced by minimizing the whole gradients in a region. The second step is to dealiase velocities by the velocity differences between different isolated regions. The velocity of an unknown isolated region is determined by the velocities of all known regions. This step improves the dealiasing results of isolated regions. In this paper, 604 volume scan samples, including typhoons, squall lines, and heavy precipitation, were used to test the algorithm. The statistical results and analysis show that the proposed algorithm can dealiase the velocity field with a high probability of detection and a low false alarm rate.

Download Full-text

Misocyclone Characteristics along Florida Gust Fronts during CaPE

Monthly Weather Review ◽

10.1175/mwr3040.1 ◽

2005 ◽

Vol 133 (11) ◽

pp. 3345-3367 ◽

Cited By ~ 16

Author(s):

Katja Friedrich ◽

David E. Kingsmill ◽

Carl R. Young

Keyword(s):

Wind Shear ◽

Doppler Radar ◽

Vertical Wind Shear ◽

Static Stability ◽

Vertical Wind ◽

Horizontal Wind ◽

Gust Fronts ◽

Convection Initiation ◽

The Relationship ◽

Gust Front

Abstract Multiple-Doppler radar and rawinsonde data are used to examine misocyclone characteristics along gust fronts observed during the Convection and Precipitation/Electrification (CaPE) project in Florida. The objective of this study is to investigate the observational representativeness of previous numerical simulations of misocyclones by employing a consistent analysis strategy to 11 gust fronts observed in the same region. The investigation focuses on the intensity range of misocyclones and their organization along gust fronts; the relationship between misocyclone intensity and horizontal wind shear, vertical wind shear, and static stability; and the relationship between misocyclones and convection initiation. The intensity of misocyclones, as indicated by the maximum values of vertical vorticity, varied from 2.8 × 10−3 to 13.9 × 10−3 s−1, although all but one case exhibited values less than 6.4 × 10−3 s−1. Organized misocyclone patterns were only found along small segments of gust fronts. Within those segments misocyclones were spaced between 3 and 7 km. Results show that the intensity of misocyclones was most closely related to the strength of horizontal wind shear across the gust front. The relationship between misocyclone intensity and vertical wind shear and static stability was not as clear. Although convection was initiated along the gust front in 7 of the 11 cases, those regions were not collocated with or in close proximity to misocyclones.

Download Full-text