The Simulation of Three-Dimensional Convective Storm Dynamics

1978 ◽  
Vol 35 (6) ◽  
pp. 1070-1096 ◽  
Author(s):  
Joseph B. Klemp ◽  
Robert B. Wilhelmson
Keyword(s):  
Three Dimensional ◽  
Convective Storm ◽  
Storm Dynamics

Evaluation of micro physical products of GPM/DPR with X-band radar network data

2021 ◽  
Author(s):  
Nobuhiro Takahashi ◽  
Takeharu Kouketsu
Keyword(s):  
Wind Speed ◽  
Three Dimensional ◽  
Vertical Wind ◽  
Network Data ◽  
Dual Frequency ◽  
Convective Storm ◽  
Radar Rainfall ◽  
Radar Network ◽  
X Band ◽  
Vertical Wind Speed

<p>One of the major characteristics of dual-frequency precipitation radar (DPR) onboard Global Precipitation Measurement (GPM) core satellite, is estimation of cloud physical properties of precipitation such as drop size distribution (DSD), existence of hail/graupel particles and possibly the mixed phase region above freezing height.  In this study, ground-based X-band radar network data are utilized for evaluate the cloud physical products from GPM/DPR.  The X-band radar network, composed of 39 X-band dual polarimetric radars developed by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) of Japan, called XRAIN[1] is utilized for the evaluation.  The XRAIN radar completes volume scan up to the elevation angle of 20 degrees in 5 minutes.  By using multiple radars, three dimensional wind field is estimated by using the dual-Doppler analysis technique.　In this analysis DSD parameter from DPR (which is called epsilon in DPR product) and dual frequency ratio (DFR) that correlate well median diameter of DSD are compared with ZDR and KDP from XRAIN data.  The vertical wind data from XRAIN is utilized to characterize the Z of DPR. The case on August 27, 2018, on which GPM satellite flew over a hail producing convective storm around Tokyo, is analyzed.  Comparison of three dimensional structure of the storm between KuPR (Ku-band radar of DPR) and XRAIN from multiple radar observations shows that both observations are quite similar each other except for the KuPR observation show rather larger volume because of the larger footprint size.  At the rain region (below freezing height), the DSD parameter of DPR (epsilon) and DFR correlate well with ZDR and KDP from XRAIN, respectively.  This result indicates the DPR algorithm works well to estimate the DSD information of rain.  The comparison of Z with vertical wind speed indicates that the higher Z is characterized as higher variance of vertical wind speed. Above the freezing height, the relationship between both observations are complicated.  This result indicates that the various types of precipitation particles not only solid particles but also liquid/mixed phase particle can exist in the severe convective storm.  The hydrometeor type classification from XRAIN by using the method by Kouketsu et al. (2015) [2] confirms that the various types of precipitation exist in this case.</p><p>References</p><p>[1] Tsuchiya, S., M. Kawasaki, H. Godo, 2015: Improvement of the radar rainfall accuracy of XRAIN by modifying of rainfall attenuation correction and compositing radar rainfall, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 2015, Volume 71, Issue 4, pp. I_457-I_462 (in Japanese with English abstract).</p><p>[2] Kouketsu, T., Uyeda, H., Ohigashi, T., Oue, M., Takeuchi, H., Shinoda, T., Tsuboki, K., Kubo, M., and Muramoto, K., 2015: A Hydrometeor Classification Method for X-Band Polarimetric Radar: Construction and Validation Focusing on Solid Hydrometeors under Moist Environments, Journal of Atmospheric and Oceanic Technology, 32(11), 2052-2074.</p>

scholarly journals Storm-Centered Ensemble Data Assimilation for Tropical Cyclones

2014 ◽  
Vol 142 (6) ◽  
pp. 2309-2320 ◽  
Author(s):  
Erika L. Navarro ◽  
Gregory J. Hakim
Keyword(s):  
Data Assimilation ◽  
Large Scale ◽  
Inner Core ◽  
Three Dimensional ◽  
Water Model ◽  
Ensemble Data Assimilation ◽  
Ensemble Data ◽  
Relative Coordinates ◽  
Order Of Magnitude ◽  
Storm Dynamics

Abstract A significant challenge for tropical cyclone ensemble data assimilation is that storm-scale observations tend to make analyses that are more asymmetric than the prior forecasts. Compromised structure and intensity, such as an increase of amplitude across the azimuthal Fourier spectrum, are a routine property of ensemble-based analyses, even with accurate position observations and frequent assimilation. Storm dynamics in subsequent forecasts evolve these states toward axisymmetry, creating difficulty in distinguishing between model-induced and actual storm asymmetries for predictability studies and forecasting. To address this issue, a novel algorithm using a storm-centered approach is proposed. The method is designed for use with existing ensemble filters with little or no modification, facilitating its adoption and maintenance. The algorithm consists of 1) an analysis of the environment using conventional coordinates, 2) a storm-centered analysis using storm-relative coordinates, and 3) a merged analysis that combines the large-scale and storm-scale fields together at an updated storm location. This algorithm is evaluated in two sets of observing system simulation experiments (OSSEs): first, no-cycling tests of the update step for idealized three-dimensional storms in radiative–convective equilibrium; second, full cycling tests of data assimilation applied to a shallow-water model for a field of interacting vortices. Results are compared against a control experiment based on a conventional ensemble Kalman filter (EnKF) scheme as well as an alternative EnKF scheme proposed by Lawson and Hansen. The storm-relative method yields vortices that are more symmetric and exhibit finer inner-core structure than either approach, with errors reduced by an order of magnitude over a control case with prior spread consistent with the National Hurricane Center (NHC)’s mean 5-yr forecast track error at 12 h. Azimuthal Fourier error spectra exhibit much-reduced noise associated with data assimilation as compared to both the control and the Lawson and Hansen approach. An assessment of free-surface height tendency of model forecasts after the merge step reveals a balanced trend between the storm-centered and conventional approaches, with storm-centered values more closely resembling the reference state.

The Evolution of Hail Production in Simulated Supercell Storms

2021 ◽  
Author(s):  
Matthew R. Kumjian ◽  
Kelly Lombardo ◽  
Scott Loeffler
Keyword(s):  
Vortex Shedding ◽  
Supercooled Liquid ◽  
Liquid Water Content ◽  
Convective Storm ◽  
True Nature ◽  
Novel Approach ◽  
Storm Evolution ◽  
Supercell Storms ◽  
Storm Dynamics ◽  
Socioeconomic Risk

AbstractHailstorms pose a significant socioeconomic risk, necessitating detailed assessments of how the hail threat changes throughout their lifetimes. Hail production involves the favorable juxtaposition of ingredients, but how storm evolution affects these ingredients is unknown, limiting understanding of how hail production evolves. Unfortunately, neither surface hail reports nor radar-based swath estimates have adequate resolution or details needed to assess evolving hail production. Instead, we use a novel approach of coupling a detailed hail trajectory model to idealized convective storm simulations to better understand storm evolution’s influence on hail production. Hail production varies substantially throughout storms’ mature phases: maximum sizes vary by a factor of two, and the concentration of severe hail more than fivefold during 45-60-min periods. This variability arises from changes in updraft properties, which come from (i) changes in low-level convergence, and (ii) internal storm dynamics, including anticyclonic vortex shedding/storm splitting, and the response of the updraft’s airflow and supercooled liquid water content to these events. Hodograph shape strongly affects such behaviors. Straighter hodographs lead to more prolific hail production through wider updrafts and weaker mesocyclones, and a periodicity in hail size metrics associated with anticyclonic vortex shedding and/or storm splitting. In contrast, a curved hodograph (favorable for tornadoes) led to a storm with a stronger but more compact updraft, which occasionally produced giant (10-cm) hail, but that was a less-prolific severe hail producer overall. Unless storms are adequately sampled throughout their lifecycles, snapshots from ground reports will insufficiently resolve the true nature of hail production.

scholarly journals A Three-Dimensional Simulation of Supercell Convective Storm

2010 ◽  
Vol 2010 ◽  
pp. 1-15 ◽  
Author(s):  
V. Spiridonov ◽  
Z. Dimitrovski ◽  
M. Curic
Keyword(s):  
High Resolution ◽  
Cloud Model ◽  
Cell Formation ◽  
Three Dimensional ◽  
Domain Size ◽  
Radar Reflectivity ◽  
Physical Parameters ◽  
Convective Storm ◽  
Cloud Resolving Model ◽  
Dimensional Simulation

A supercell convective storm is simulated by using a cloud-resolving model. Numerical experiments have been performed in 3D by using the same domain size, with a different spatial and temporal resolution of the model. High-resolution cloud model has been shown to represent convective processing quite well. Running the model in a high-resolution mode gives a more realistic view of the life cycle of convective storm, internal structure, and storm behavior. The storm structure and evolutionary properties are evaluated by comparing the modeled radar reflectivity to the observed radar reflectivity. The comparative analysis between physical parameters shows good agreement among both model runs and compares well with observations, especially using a fine spatial resolution. The lack of measurements of these species in the convective outflow region does not allow us to evaluate the model results with observations. A three-dimensional simulation using higher grid resolution mode exhibits interesting features which include a double vortex circulation, cell splitting, and secondary cell formation.

scholarly journals Automated thunderstorm tracking: utilization of three-dimensional lightning- and radar data

2013 ◽  
Vol 13 (1) ◽  
pp. 2179-2216 ◽  
Author(s):  
V. K. Meyer ◽  
H. Höller ◽  
H. D. Betz
Keyword(s):  
Hybrid Method ◽  
Three Dimensional ◽  
Active Regions ◽  
Radar Data ◽  
Close Monitoring ◽  
Continuous Assessment ◽  
Storm Evolution ◽  
Comprehensive Picture ◽  
Storm Dynamics ◽  
Total Lightning

Abstract. This paper presents a new hybrid method for automated thunderstorm observation by tracking and monitoring of electrically charged cells (ec-TRAM). The developed algorithm combines information about intense ground precipitation derived from low-level radar-reflectivity scans with three-dimensionally resolved lightning data, which are provided by the European VLF/LF lightning detection network LINET. Based on the already existing automated radar tracker rad-TRAM (Kober and Tafferner, 2009), the new method li-TRAM identifies and tracks electrically active regions in thunderclouds using lightning data only. The algorithm ec-TRAM uses the output of the two autonomously operating routines rad-TRAM and li-TRAM in order to assess, track, and monitor a more comprehensive picture of thunderstorms. The main motivation of this work is to assess the benefit of three-dimensionally resolved total lightning information (TL) for thunderstorm tracking and nowcasting. The focus is laid on the temporal development whereby TL is characterized by an effective in-cloud (IC) and cloud-to-ground (CG) event-discrimination. It is found that the algorithms li-TRAM and ec-TRAM are both feasible methods for thunderstorm nowcasting. The tracking performance of li-TRAM turns out to be comparable to that of rad-TRAM, a result that strongly encourages utilization of lightning data as independent data source for thunderstorm tracking. It is found that lightning data allow an accurate and close monitoring of storm regions with intense internal dynamics as soon as convection induces electrical activity. A case study shows that the current short-term storm dynamics are clearly reflected in the amount of strokes, change of stroke rates and IC/CG ratio. The hybrid method ec-TRAM outperforms rad-TRAM and li-TRAM regarding reliability and continuous assessment of storm tracks especially in more complexly developing storms, where the use of discharge information contributes to more detailed information about storm stage and storm evolution.

scholarly journals Automated thunderstorm tracking: utilization of three-dimensional lightning and radar data

2013 ◽  
Vol 13 (10) ◽  
pp. 5137-5150 ◽  
Author(s):  
V. K. Meyer ◽  
H. Höller ◽  
H. D. Betz
Keyword(s):  
Hybrid Method ◽  
Three Dimensional ◽  
Active Regions ◽  
Radar Data ◽  
Close Monitoring ◽  
Continuous Assessment ◽  
Storm Evolution ◽  
Comprehensive Picture ◽  
Storm Dynamics ◽  
Total Lightning

Abstract. This paper presents a new hybrid method for automated thunderstorm observation by tracking and monitoring of electrically charged cells (ec-TRAM). The developed algorithm combines information about intense ground precipitation derived from low-level radar-reflectivity scans with three-dimensionally resolved lightning data, which are provided by the European VLF/LF lightning detection network LINET. Based on the already existing automated radar tracker rad-TRAM (Kober and Tafferner, 2009), the new method li-TRAM identifies and tracks electrically active regions in thunderclouds using lightning data only. The algorithm ec-TRAM uses the output of the two autonomously operating routines rad-TRAM and li-TRAM in order to assess, track, and monitor a more comprehensive picture of thunderstorms. The main motivation of this work is to assess the benefit of three-dimensionally resolved total lightning (TL) information for thunderstorm tracking and monitoring. The focus is laid on the temporal development whereby TL is characterized by an effective in-cloud (IC) and cloud-to-ground (CG) event discrimination. It is found that the algorithms li-TRAM and ec-TRAM are both feasible methods for thunderstorm monitoring with potential for nowcasting. The tracking performance of li-TRAM turns out to be comparable to that of rad-TRAM, a result that strongly encourages utilization of lightning data as independent data source for thunderstorm tracking. It is found that lightning data allow an accurate and close monitoring of storm regions with intense internal dynamics as soon as convection induces electrical activity. A case study shows that the current short-term storm dynamics are clearly reflected in the amount of strokes, change of stroke rates and IC/CG ratio. The hybrid method ec-TRAM outperforms rad-TRAM and li-TRAM regarding reliability and continuous assessment of storm tracks especially in more complexly developing storms, where the use of discharge information contributes to more detailed information about storm stage and storm evolution.

scholarly journals Urban Aerosol Impacts on Downwind Convective Storms

2007 ◽  
Vol 46 (6) ◽  
pp. 828-850 ◽  
Author(s):  
Susan C. van den Heever ◽  
William R. Cotton
Keyword(s):  
Mesoscale Model ◽  
Cold Pool ◽  
Urban Aerosol ◽  
Convective Storm ◽  
Urban Centers ◽  
Surface Precipitation ◽  
Convective Storms ◽  
Unique Character ◽  
Storm Dynamics ◽  
The City

Abstract The impacts of urban-enhanced aerosol concentrations on convective storm development and precipitation over and downwind of St. Louis, Missouri, are investigated. This is achieved through the use of a cloud-resolving mesoscale model, in which sophisticated land use processes and aerosol microphysics are both incorporated. The results indicate that urban-forced convergence downwind of the city, rather than the presence of greater aerosol concentrations, determines whether storms actually develop in the downwind region. Once convection is initiated, urban-enhanced aerosols can exert a significant effect on the dynamics, microphysics, and precipitation produced by these storms. The model results indicate, however, that the response to urban-enhanced aerosol depends on the background concentrations of aerosols; a weaker response occurs with increasing background aerosol concentrations. The effects of aerosols influence the rate and amount of liquid water and ice produced within these storms, the accumulated surface precipitation, the strength and timing of the updrafts and downdrafts, the longevity of the updrafts, and the strength and influence of the cold pool. Complex, nonlinear relationships and feedbacks between the microphysics and storm dynamics exist, making it difficult to make definitive statements about the effects of urban-enhanced aerosols on downwind precipitation and convection. Because the impacts of urban aerosol on downwind storms decrease with increasing background aerosol concentrations, generalization of these results depends on the unique character of background aerosol for each urban area. For urban centers in coastal areas where background aerosol concentrations may be very low, it is speculated that urban aerosol can have very large influences on convective storm dynamics, microphysics, and precipitation.

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