scholarly journals Thunderstorms in Corsica Island measured during the EXAEDRE aircraft campaign

2021 ◽  
Author(s):  
Keunok Lee ◽  
Eric Defer ◽  
Pauline Combarnous ◽  
Jean-Pierre Pinty ◽  
Magalie Buguet ◽  
...  
Keyword(s):  
Atmospheric Electricity ◽  
Convective Cloud ◽  
Cloud Microphysics ◽  
Convective Systems ◽  
Cloud Radar ◽  
Weather Radars ◽  
Cloud Resolving Model ◽  
Mapping Array ◽  
Locating System ◽  
Horizontal Grid

<p>The aim of this study is to enhance our understanding about the microphysical structure of convective cloud systems and its relationships to the ambient electrical field, and to assess the capability of a model to capture the cloud electrical properties. This study relies on the EXAEDRE (EXploiting new Atmospheric Electricity Data for Research and the Environment) aircraft campaign that took place from 13 September to 8 October 2018 in Corsica Island. Eight electrified convective systems were successfully sampled during the campaign by the French Falcon 20 aircraft (e.g. RASTA Doppler cloud radar, microphysics probes, electric field mills) and ground-based platforms (Lightning Mapping Array network, Météorage operational lightning locating system and Météo-France weather radars). In this study, a multi-cell thunderstorm which developed over the complex topography of Corsica Island on 17 September 2018 was selected to investigate and to understand the physical processes linking lightning occurrence, electrification efficiency, cloud microphysics and dynamics. The detailed analysis results using the unprecedented airborne and ground-based dataset and their comparison to the numerical simulation results with a horizontal grid spacing of 1 km comprising the explicit electrical scheme CELLS (Cloud Electrification and Lightning Scheme) implemented in the cloud resolving model Meso-NH has been conducted. The key results will be presented at the conference.</p>

scholarly journals Reconstruction of cloud geometry using a scanning cloud radar

2015 ◽  
Vol 8 (6) ◽  
pp. 2491-2508 ◽  
Author(s):  
F. Ewald ◽  
C. Winkler ◽  
T. Zinner
Keyword(s):  
Remote Sensing ◽  
Radiative Transfer ◽  
Interpolation Method ◽  
Three Dimensional ◽  
Convective Cloud ◽  
Cloud Microphysics ◽  
Reconstruction Method ◽  
Cloud Radar ◽  
Barycentric Interpolation ◽  
Microphysical Parameters

Abstract. Clouds are one of the main reasons of uncertainties in the forecasts of weather and climate. In part, this is due to limitations of remote sensing of cloud microphysics. Present approaches often use passive spectral measurements for the remote sensing of cloud microphysical parameters. Large uncertainties are introduced by three-dimensional (3-D) radiative transfer effects and cloud inhomogeneities. Such effects are largely caused by unknown orientation of cloud sides or by shadowed areas on the cloud. Passive ground-based remote sensing of cloud properties at high spatial resolution could be crucially improved with this kind of additional knowledge of cloud geometry. To this end, a method for the accurate reconstruction of 3-D cloud geometry from cloud radar measurements is developed in this work. Using a radar simulator and simulated passive measurements of model clouds based on a large eddy simulation (LES), the effects of different radar scan resolutions and varying interpolation methods are evaluated. In reality, a trade-off between scan resolution and scan duration has to be found as clouds change quickly. A reasonable choice is a scan resolution of 1 to 2\\degree. The most suitable interpolation procedure identified is the barycentric interpolation method. The 3-D reconstruction method is demonstrated using radar scans of convective cloud cases with the Munich miraMACS, a 35 GHz scanning cloud radar. As a successful proof of concept, camera imagery collected at the radar location is reproduced for the observed cloud cases via 3-D volume reconstruction and 3-D radiative transfer simulation. Data sets provided by the presented reconstruction method will aid passive spectral ground-based measurements of cloud sides to retrieve microphysical parameters.

scholarly journals Reconstruction of 3-D cloud geometry using a scanning cloud radar

2014 ◽  
Vol 7 (11) ◽  
pp. 11345-11378
Author(s):  
F. Ewald ◽  
C. Winkler ◽  
T. Zinner
Keyword(s):  
Remote Sensing ◽  
Radiative Transfer ◽  
Interpolation Method ◽  
Three Dimensional ◽  
Convective Cloud ◽  
Cloud Microphysics ◽  
Reconstruction Method ◽  
Cloud Radar ◽  
Barycentric Interpolation ◽  
Microphysical Parameters

Abstract. Clouds are one of the main reasons of uncertainties in the forecasts of weather and climate. In part, this is due to limitations of remote sensing of cloud microphysics. Present approaches often use passive spectral measurements for the remote sensing of cloud microphysical parameters. Large uncertainties are introduced by three dimensional (3-D) radiative transfer effects and cloud inhomogeneities. Such effects are largely caused by unknown orientation of cloud sides or by shadowed areas on the cloud. Passive ground based remote sensing of cloud properties at high spatial resolution could be improved crucially with this kind of additional knowledge of cloud geometry. To this end, a method for the accurate reconstruction of 3-D cloud geometry from cloud radar measurements is developed in this work. Using a radar simulator and simulated passive measurements of static LES model clouds, the effects of different radar scan resolutions and varying interpolation methods are evaluated. In reality a trade-off between scan resolution and scan duration has to be found as clouds are changing quickly. A reasonable choice is a scan resolution of 1 to 2°. The most suitable interpolation procedure identified is the barycentric interpolation method. The 3-D reconstruction method is demonstrated using radar scans of convective cloud cases with the Munich miraMACS, a 35 GHz scanning cloud radar. As a successful proof of concept, camera imagery collected at the radar location is reproduced for the observed cloud cases via 3-D volume reconstruction and 3-D radiative transfer simulation. Data sets provided by the presented reconstruction method will aid passive spectral ground-based measurements of cloud sides to retrieve microphysical parameters.

scholarly journals Classification of Hydrometeors Using Measurements of the Ka-Band Cloud Radar Installed at the Milešovka Mountain (Central Europe)

2018 ◽  
Vol 10 (11) ◽  
pp. 1674 ◽  
Author(s):  
Zbyněk Sokol ◽  
Jana Minářová ◽  
Petr Novák
Keyword(s):  
Central Europe ◽  
Terminal Velocity ◽  
Small Particles ◽  
Cloud Droplets ◽  
Vertical Temperature Profile ◽  
Ka Band ◽  
Cloud Radar ◽  
Weather Radars ◽  
Cloud Particles ◽  
Linear Depolarization Ratio

In radar meteorology, greater interest is dedicated to weather radars and precipitation analyses. However, cloud radars provide us with detailed information on cloud particles from which the precipitation consists of. Motivated by research on the cloud particles, a vertical Ka-band cloud radar (35 GHz) was installed at the Milešovka observatory in Central Europe and was operationally measuring since June 2018. This study presents algorithms that we use to retrieve vertical air velocity (Vair) and hydrometeors. The algorithm calculating Vair is based on small-particle tracers, which considers the terminal velocity of small particles negligible and, thereby, Vair corresponds to the velocity of the small particles. The algorithm classifying hydrometeors consists of calculating the terminal velocity of hydrometeors and the vertical temperature profile. It identifies six hydrometeor types (cloud droplets, ice, and four precipitating particles: rain, graupel, snow, and hail) based on the calculated terminal velocity of hydrometeors, temperature, Vair, and Linear Depolarization Ratio. The results of both the Vair and the distribution of hydrometeors were found to be realistic for a thunderstorm associated with significant lightning activity on 1 June 2018.

scholarly journals A study of the relationship between cloud-to-ground lightning and precipitation in the convective weather system in China

2002 ◽  
Vol 20 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Y. Zhou ◽  
X. Qie ◽  
S. Soula
Keyword(s):  
Atmospheric Electricity ◽  
Estimation Method ◽  
Gansu Province ◽  
Lightning Flash ◽  
Weather System ◽  
Convective Systems ◽  
Observation Area ◽  
Precipitation Estimation ◽  
Convective Weather ◽  
Cg Lightning

Abstract. In this paper, the correlation between cloud-to-ground (CG) lightning and precipitation has been studied by making use of the data from weather radar, meteorological soundings, and a lightning location system that includes three direction finders about 40 km apart from each other in the Pingliang area of east Gansu province in P. R. China. We have studied the convective systems that developed during two cold front processes passing over the observation area, and found that the CG lightning can be an important factor in the precipitation estimation. The regression equation between the average precipitation intensity (R) and the number of CG lightning flashes (L) in the main precipitation period is R = 1.69 ln (L) - 0.27, and the correlation coefficient r is 0.86. The CG lightning flash rate can be used as an indicator of the formation and development of the convective weather system. Another more exhaustive precipitation estimation method has been developed by analyzing the temporal and spatial distributions of the precipitation relative to the location of the CG lightning flashes. Precipitation calculated from the CG lightning flashes is very useful, especially in regions with inadequate radar cover.Key words. Meteorology and atmospheric dynamics (atmospheric electricity; lightning; precipitation)

scholarly journals The Cloud-resolving model Radar SIMulator (CR-SIM) Version 3.3: description and applications of a virtual observatory

2020 ◽  
Vol 13 (4) ◽  
pp. 1975-1998 ◽  
Author(s):  
Mariko Oue ◽  
Aleksandra Tatarevic ◽  
Pavlos Kollias ◽  
Dié Wang ◽  
Kwangmin Yu ◽  
...  
Keyword(s):  
High Resolution ◽  
Climate Models ◽  
Model Simulation ◽  
Atmospheric Model ◽  
Cloud Microphysics ◽  
Virtual Observatory ◽  
Design Strategies ◽  
Modeling Framework ◽  
Cloud Resolving Model ◽  
Radar Simulator

Abstract. Ground-based observatories use multisensor observations to characterize cloud and precipitation properties. One of the challenges is how to design strategies to best use these observations to understand these properties and evaluate weather and climate models. This paper introduces the Cloud-resolving model Radar SIMulator (CR-SIM), which uses output from high-resolution cloud-resolving models (CRMs) to emulate multiwavelength, zenith-pointing, and scanning radar observables and multisensor (radar and lidar) products. CR-SIM allows for direct comparison between an atmospheric model simulation and remote-sensing products using a forward-modeling framework consistent with the microphysical assumptions used in the atmospheric model. CR-SIM has the flexibility to easily incorporate additional microphysical modules, such as microphysical schemes and scattering calculations, and expand the applications to simulate multisensor retrieval products. In this paper, we present several applications of CR-SIM for evaluating the representativeness of cloud microphysics and dynamics in a CRM, quantifying uncertainties in radar–lidar integrated cloud products and multi-Doppler wind retrievals, and optimizing radar sampling strategy using observing system simulation experiments. These applications demonstrate CR-SIM as a virtual observatory operator on high-resolution model output for a consistent comparison between model results and observations to aid interpretation of the differences and improve understanding of the representativeness errors due to the sampling limitations of the ground-based measurements. CR-SIM is licensed under the GNU GPL package and both the software and the user guide are publicly available to the scientific community.

scholarly journals Sensitivity of a Cloud-Resolving Model to Bulk and Explicit Bin Microphysical Schemes. Part I: Comparisons

2009 ◽  
Vol 66 (1) ◽  
pp. 3-21 ◽  
Author(s):  
Xiaowen Li ◽  
Wei-Kuo Tao ◽  
Alexander P. Khain ◽  
Joanne Simpson ◽  
Daniel E. Johnson
Keyword(s):  
Cloud Microphysics ◽  
Squall Line ◽  
Mature Stage ◽  
High Temporal Resolution ◽  
Stratiform Region ◽  
Storm Flow ◽  
Cloud Resolving Model ◽  
Storm Dynamics ◽  
Convective Cells ◽  
Heating Profiles

Abstract A two-dimensional cloud-resolving model is used to study the sensitivities of two microphysical schemes, a bulk scheme and an explicit spectral bin scheme, in simulating a midlatitude summertime squall line [Preliminary Regional Experiment for Storm-Scale Operational and Research Meteorology (PRE-STORM), 10–11 June 1985]. In this first part of a two-part paper, the developing and mature stages of simulated storms are compared in detail. Some variables observed during the field campaign are also presented for validation. It is found that both schemes agree well with each other, and also with published observations and retrievals, in terms of storm structures and evolution, average storm flow patterns, pressure and temperature perturbations, and total heating profiles. The bin scheme is able to produce a much more extensive and homogeneous stratiform region, which compares better with observations. However, instantaneous fields and high temporal resolution analyses show distinct characteristics in the two simulations. During the mature stage, the bulk simulation produces a multicell storm with convective cells embedded in its stratiform region. Its leading convection also shows a distinct life cycle (strong evolution). In contrast, the bin simulation produces a unicell storm with little temporal variation in its leading cell regeneration (weak evolution). More detailed, high-resolution observations are needed to validate and, perhaps, generalize these model results. Interactions between the cloud microphysics and storm dynamics that produce the sensitivities described here are discussed in detail in Part II of this paper.

Characterizing precipitation in convective cloud regimes in the trades with the polarimetric C-band radar POLDIRAD

2020 ◽  
Author(s):  
Martin Hagen ◽  
Florian Ewald ◽  
Silke Groß ◽  
Qiang Li ◽  
Lothar Oswald ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
High Resolution ◽  
Temporal Evolution ◽  
Convective Cloud ◽  
Weather Radar ◽  
Cloud Microphysics ◽  
Radiation Budget ◽  
Precipitation Pattern ◽  
Aircraft Measurements ◽  
The Earth

<p>Low-level clouds in the trade regions play an important role in the Earth’s climate system since they have a considerable influence on the Earth’s radiation budget. However, the understanding of the coupling between cloud dynamics, cloud microphysics, and mesoscale organization is limited. This results in a large uncertainty in current climate predictions. Despite the importance, observations in these regions are limited. Geostationary satellites cannot provide high resolution three-dimensional details of clouds and precipitation. Polar orbiting satellites like the A-Train satellites Cloudsat and Calipso or the upcoming EarthCARE satellite do provide detailed profiles of cloud properties, but the temporal evolution cannot be observed. On the other hand, long range weather radar observations can provide both, high spatial and temporal observations, however not many weather radar do cover the trades.</p><p>During the Eurec4a campaign DLRs C-band polarimetric weather radar POLDIRAD was installed on the island of Barbados. The scope of the radar measurements is manifold:</p><p>- POLDIRAD will provide high resolution observations of the different mesoscale cloud patterns as observed from satellites: Flowers, Gravel, Fish, and Sugar. Will the mesoscale organization have an influence on observable microphysical properties?</p><p>- POLDIRAD will put the detailed measurements by aircraft (in situ and remote sensing) into a greater context. How are the aircraft measurements related to the spatial distribution of the precipitation pattern? How are the aircraft measurements related to the temporal evolution of the precipitation pattern?</p><p>- POLDIRAD will put the observed profiles of clouds and precipitation at the Barbados Cloud Observatory BCO at Deebles Point into a greater context. How are the profile measurements related to the spatial distribution of the precipitation pattern? How are the profile measurements related to the temporal evolution of the precipitation pattern?</p>

A Wave-Relative Framework Analysis of AEW–MCS Interactions Leading to Tropical Cyclogenesis

2020 ◽  
Vol 148 (11) ◽  
pp. 4657-4671
Author(s):  
Kelly M. Núñez Ocasio ◽  
Jenni L. Evans ◽  
George S. Young
Keyword(s):  
West Africa ◽  
Thermodynamic Characteristics ◽  
Convective Cloud ◽  
Type Systems ◽  
Squall Line ◽  
Tropical Cyclogenesis ◽  
Framework Analysis ◽  
Convective Systems ◽  
Cloud Clusters ◽  
Mesoscale Convective

AbstractAn African easterly wave (AEW) and associated mesoscale convective systems (MCSs) dataset has been created and used to evaluate the propagation of MCSs, AEWs, and, especially, the propagation of MCSs relative to the AEW with which they are associated (i.e., wave-relative framework). The thermodynamic characteristics of AEW–MCS systems are also analyzed. The analysis is done for both AEW–MCS systems that develop into tropical cyclones and those that do not to quantify significant differences. It is shown that developing AEWs over West Africa are associated with a larger number of convective cloud clusters (CCCs; squall-line-type systems) than nondeveloping AEWs. The MCSs of developing AEWs propagate at the same speed of the AEW trough in addition to being in phase with the trough, whereas convection associated with nondeveloping AEWs over West Africa moves faster than the trough and is positioned south of it. These differences become important for the intensification of the AEW vortex as this slower-moving convection (i.e., moving at the same speed of the AEW trough) spends more time supplying moisture and latent heat to the AEW vortex, supporting its further intensification. An analysis of the rainfall rate (MCS intensity), MCS area, and latent heating rate contribution reveals that there are statistically significant differences between developing AEWs and nondeveloping AEWs, especially over West Africa where the fraction of extremely large MCS areas associated with developing AEWs is larger than for nondeveloping AEWs.

Sign in / Sign up

Export Citation Format

Share Document