VHF/UHF radar observations of tropical mesoscale convective systems over southern India

Abstract. Several campaigns have been carried out to study the convective systems over Gadanki (13.5° N, 79.2° E), a tropical station in India, using VHF and UHF radars. The height-time sections of several convective systems are investigated in detail to study reflectivity, turbulence and vertical velocity structure. Structure and dynamics of the convective systems are the main objectives of these campaigns. The observed systems are classified into single- and multi-cell systems. It has been observed that most of the convective systems at this latitude are multi-cellular in nature. Simultaneous VHF and UHF radar observations are used to classify the observed precipitating systems as convective, intermediary and stratiform regions. Composite height profiles of vertical velocities in these regions were obtained and the same were compared with the profiles obtained at other geographical locations. These composite profiles of vertical velocity in the convective regions have shown their peaks in the mid troposphere, indicating that the maximum latent heat is being released at those heights. These profiles are very important for numerical simulations of the convective systems, which vary significantly from one geographical location to the other. Keywords. Meteorology and atmospheric dynamics (Mesoscale meteorology; Convective processes) – Radio science (Remote sensing)

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Comparing the Convective Structure and Microphysics in Two Sahelian Mesoscale Convective Systems: Radar Observations and CRM Simulations

Monthly Weather Review ◽

10.1175/mwr-d-12-00053.1 ◽

2013 ◽

Vol 141 (2) ◽

pp. 582-601 ◽

Cited By ~ 6

Author(s):

Nick Guy ◽

Xiping Zeng ◽

Steven A. Rutledge ◽

Wei-Kuo Tao

Keyword(s):

Three Dimensional ◽

Mesoscale Convective Systems ◽

Modeling Framework ◽

Microphysics Scheme ◽

Radar Observations ◽

Convective Systems ◽

Convective Structure ◽

High Reflectivity ◽

Mesoscale Convective ◽

Cloud Resolving Model

Abstract Two mesoscale convective systems (MCSs) observed during the African Monsoon Multidisciplinary Analyses (AMMA) experiment are simulated using the three-dimensional (3D) Goddard Cumulus Ensemble model. This study was undertaken to determine the performance of the cloud-resolving model in representing distinct convective and microphysical differences between the two MCSs over a tropical continental location. Simulations are performed using 1-km horizontal grid spacing, a lower limit on current embedded cloud-resolving models within a global multiscale modeling framework. Simulated system convective structure and microphysics are compared to radar observations using contoured frequency-by-altitude diagrams (CFADs), calculated ice and water mass, and identified hydrometeor variables. Vertical distributions of ice hydrometeors indicate underestimation at the mid- and upper levels, partially due to the inability of the model to produce adequate system heights. The abundance of high-reflectivity values below and near the melting level in the simulation led to a broadening of the CFAD distributions. Observed vertical reflectivity profiles show that high reflectivity is present at greater heights than the simulations produced, thought to be a result of using a single-moment microphysics scheme. Relative trends in the population of simulated hydrometeors are in agreement with observations, though a secondary convective burst is not well represented. Despite these biases, the radar-observed differences between the two cases are noticeable in the simulations as well, suggesting that the model has some skill in capturing observed differences between the two MCSs.

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Comparison of Simulated and Observed Continental Tropical Anvil Clouds and Their Radiative Heating Profiles

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-11-0251.1 ◽

2012 ◽

Vol 69 (9) ◽

pp. 2662-2681 ◽

Cited By ~ 28

Author(s):

Scott W. Powell ◽

Robert A. Houze ◽

Anil Kumar ◽

Sally A. McFarlane

Keyword(s):

Mesoscale Model ◽

Model Performance ◽

Radar Data ◽

Radiative Heating ◽

Radar Observations ◽

Convective Systems ◽

Mesoscale Convective ◽

Atmospheric Radiation Measurement ◽

Stringent Test ◽

Heating Profiles

Abstract Vertically pointing millimeter-wavelength radar observations of anvil clouds extending from mesoscale convective systems (MCSs) that pass over an Atmospheric Radiation Measurement Program (ARM) field site in Niamey, Niger, are compared to anvil structures generated by the Weather Research and Forecasting (WRF) mesoscale model using six different microphysical schemes. The radar data provide the statistical distribution of the radar reflectivity values as a function of height and anvil thickness. These statistics are compared to the statistics of the modeled anvil cloud reflectivity at all altitudes. Requiring the model to be statistically accurate at all altitudes is a stringent test of the model performance. The typical vertical profile of radiative heating in the anvil clouds is computed from the radar observations. Variability of anvil structures from the different microphysical schemes provides an estimate of the inherent uncertainty in anvil radiative heating profiles. All schemes underestimate the optical thickness of thin anvils and cirrus, resulting in a bias of excessive net anvil heating in all of the simulations.

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Aboveground Thermodynamic Observations in Convective Storms from Balloonborne Probes Acting as Pseudo-Lagrangian Drifters

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-17-0204.1 ◽

2018 ◽

Vol 99 (4) ◽

pp. 711-724 ◽

Cited By ~ 4

Author(s):

Paul M. Markowski ◽

Yvette P. Richardson ◽

Scott J. Richardson ◽

Anders Petersson

Keyword(s):

Mesoscale Meteorology ◽

Severe Storms ◽

Convective Storms ◽

Convective Systems ◽

Lagrangian Drifters ◽

Straight Line ◽

Mesoscale Convective ◽

Supercell Storms ◽

Lagrangian Drifter

AbstractThe severe storms research community lacks reliable, aboveground, thermodynamic observations (e.g., temperature, humidity, and pressure) in convective storms. These missing observations are crucial to understanding the behavior of both supercell storms (e.g., the generation, reorientation, and amplification of vorticity necessary for tornado formation) and larger-scale (mesoscale) convective systems (e.g., storm maintenance and the generation of damaging straight-line winds). This paper describes a novel way to use balloonborne probes to obtain aboveground thermodynamic observations. Each probe is carried by a pair of balloons until one of the balloons is jettisoned; the remaining balloon and probe act as a pseudo-Lagrangian drifter that is drawn through the storm. Preliminary data are presented from a pair of deployments in supercell storms in Oklahoma and Kansas during May 2017. The versatility of the observing system extends beyond severe storms applications into any area of mesoscale meteorology in which a large array of aboveground, in situ thermodynamic observations are needed.

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