Study of Turbulence Associated with the Faraji Cyclone

Ciardullo, Giuseppe; Primavera, Leonardo; Ferrucci, F.; Carbone, V.; Lepreti, F.

doi:10.3390/cli10020021

Cited by 3 publications

(12 citation statements)

References 17 publications

(33 reference statements)

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“…air temperature and altitude quantities. In paper [9], by analyzing the brightness temperature, we found there was a strict correspondence between the modes of the POD spectrum and the corresponding Fourier modes computed through an ordinary two-dimensional Fast Fourier Transform and by averaging in time the shell-integrated spectra of each single snapshot of the brightness temperature, it was possible to clearly distinguish in the resulting spectrum three different zones. We interpreted the presence of these two breakpoints in the spectrum of the temperature as due to a change, at given scales, in the dynamics of turbulent motions.…”

Section: Geostationary Data Analysismentioning

confidence: 90%

“…For cases of non-homogeneous and anisotropic fluids, as the examined event can be considered, many studies of the turbulent evolution of the structures that characterize the system have been carried out. In particular, the technique chosen in this work for this type of analysis is the Proper Orthogonal Decomposition [9][10][11][12][13] method. This technique allows to obtain an optimal decomposition of a scalar or vector field defined on a space-time domain.…”

Section: Geostationary Instrument Analysismentioning

confidence: 99%

“…The spectrum shows, also in this case, the fitting power law that gives the spectral indices separately for the three-scales classification previously discussed. If we consider a direct comparison with the spectrum obtained from the brightness temperature field, we can immediately see that the two are identical, and the slope assessment is given according to the same empirical criterion [9]. Moreover, we start from the assumption that in the three zones of the spectrum, that we call Z1, Z2 and Z3, the energy E(k) as a function of the modulus of the wavevector K = |k| obeys to a power law with spectral index α.…”

Section: Geostationary Data Analysismentioning

confidence: 99%

“…The first part of the work is centered on data collected during the rapid intensification phase of the Indian-Ocean hurricane Faraji, by the Spinning Enhanced Visible Infra-Red Imager (SEVIRI) radiometer, orbiting onboard the geostationary satellite Meteosat Second Generation 8 Indian Ocean Data Collection (MSG-8 IODC) [8]. With this specific database, an in-depth study of the spatiotemporal dynamics of Faraji using the proper orthogonal decomposition (POD) technique was carried out [9][10][11][12][13]. This technique allows to extract a set of empirical basis functions from a generic ensemble of snapshots (typically representing the time evolution) of a field, that can therefore be written as a linear superposition of orthogonal eigenfunctions, the so-called POD modes.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the spatial and temporal components of the dynamics, described by the extracted eigenfunctions and coefficients, respectively, are factorized and while the eigenfunctions keep into account the spatial distribution of the energy of the field, the coefficients account for its temporal dynamics. In [9], we carried out this analysis to extract the POD eigenfunctions and coefficients from a collection of satellite products related to the brightness temperature of the Faraji cyclone. From this extraction, the energy content is studied by separating the two components and building up energy spectra, in which it is possible to visualize how the hurricane evolves into three different characteristic ranges of scales.…”

Section: Introductionmentioning

confidence: 99%

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New Investigation of a Tropical Cyclone: Observational and Turbulence Analysis for the Faraji Hurricane

et al. 2023

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In the general framework of the atmosphere, the in-depth study of extreme events of complex nature such as tropical cyclones remains an open problem. Nowadays, there are different useful studies aiming to enlarge the current knowledge of these events. Under this perspective, the search for mechanisms and geographical areas of formation and dynamics of tropical cyclones at different latitudes needs better constraints on their preliminary results.This work focuses on a diagnostic analysis of a tropical cyclone, with the aim of identifying key points that characterize its evolution, from a dynamic and observational point of view. The study is applied to Hurricane Faraji, the most powerful tropical cyclone of the 2021 Indian Ocean season, classified as fifth-category on the Saffir–Simpson intensity scale. The study develops in three main sections, all related to each other. The starting point is a large set of satellite products from both polar and geostationary platforms. From the data acquired by the polar instruments, an accurate study of the evolution of the hurricane is carried out, focused on the extraction of physical information related to the system (temperature and altitude of the associated cloudy system, temperature gradient, pressure in the different regions) at moderate resolutions. From the data acquired by the geostationary instruments, it is possible to obtain very high temporal resolution pictures of the temperature field of the cyclone, from which a study of the turbulent dynamics is carried out. In particular, to investigate the maximum energy content in the different regions of the cyclone, the Proper Orthogonal Decomposition (POD) technique is used to extract the associated spectra of both the spatial and temporal components, studied separately on three different ranges of scales.

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Section: Geostationary Data Analysismentioning

confidence: 90%

Section: Geostationary Instrument Analysismentioning

confidence: 99%

Section: Geostationary Data Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New Investigation of a Tropical Cyclone: Observational and Turbulence Analysis for the Faraji Hurricane

et al. 2023

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A Satellite Analysis: Comparing Two Medicanes

Ciardullo,

Primavera,

Ferrucci

et al. 2024

Atmosphere

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Morphological features of the Mediterranean Sea basin have recently been precursors to a significant increase in the formation of extreme events, in relation to climate change effects. It happens very frequently that rotating air masses and the formation of mesoscale vortices can evolve into events with characteristics similar to large-scale tropical cyclones. Generally, they are less intense, with smaller size and duration; thus, they are called Medicanes, a short name for Mediterranean hurricanes, or tropical-like cyclones (TLCs). In this paper, we propose a new perspective for the study and analysis of cyclonic events, starting with data and images acquired from satellites and focusing on the diagnostics of the evolution of atmospheric parameters for these events. More precisely, satellite remote sensing techniques are employed to elaborate on different high spatial-resolution satellite images of the events at a given sensing time. Two case studies are examined, taking into account their development into Medicane stages: Ianos, which intensified in the Ionian Sea and reached the coast of Greece between 14 and 21 September 2020, and Apollo, which impacted Mediterranean latitudes with a long tracking from 24 October to 2 November 2021. For these events, 20 images were acquired from two different satellite sensors, onboard two low-Earth orbit (LEO) platforms, by deeply exploiting their thermal infrared (TIR) spectral channels. A useful extraction of significant physical information was carried out from every image, highlighting several atmospheric quantities, including temperature and altitude layers from the top of the cloud, vertical temperature gradient, atmospheric pressure field, and deep convection cloud. The diagnostics of the two events were investigated through the spatial scale capabilities of the instruments and the spatiotemporal evolution of the cyclones, including the comparison between satellite data and recording data from the BOLAM forecasting model. In addition, 384 images were extracted from the geostationary (GEO) satellite platform for the investigation of the events’ one-day structure intensification, by implementing time as the third dimension.

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New investigation of a tropical cyclone: observational and turbulence analysis for the Faraji hurricane

Ciardullo

Primavera²,

Ferrucci³

et al. 2023

Preprint

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<p>In the general framework of the atmosphere, the in-depth study of extreme events of complex nature such as tropical cyclones remains an open problem. Nowadays, it is possible to study and predict the directionality that a cyclone can acquire in a very short term. However, the search for mechanisms and geographical areas of formation and dynamics of such events in different regions needs better constraints on the preliminary nature of the current results. This work focuses on a diagnostic analysis of a tropical cyclone, with the aim of identifying key points that characterize its evolution, from a dynamic and observational point of view. The study is applied to Hurricane Faraji, the most powerful tropical cyclone of the 2021 Indian Ocean season, classified as fifth-category on the Saffir-Simpson intensity scale. The study develops in three main sections, all related to each other. The starting point is a large set of satellite products from both polar and geostationary platforms. From the data acquired by the polar instruments, an accurate study of the evolution of the hurricane is carried out, focused on the extraction of physical information related to the system (temperature and altitude of the associated cloudy system, temperature gradient, pressure in the different regions) at moderate resolutions. From the data acquired by the geostationary instruments, it is possible to obtain very high temporal resolution pictures of the temperature field of the cyclone, from which a study of the turbulent dynamics is carried out. In particular, to investigate the maximum energy content in the different regions of the cyclone, the Proper Orthogonal Decomposition (POD) technique is used to extract the associated spectra of both the spatial and temporal components, studied separately on three different ranges of scales.</p>

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Study of Turbulence Associated with the Faraji Cyclone

Cited by 3 publications

References 17 publications

New Investigation of a Tropical Cyclone: Observational and Turbulence Analysis for the Faraji Hurricane

New Investigation of a Tropical Cyclone: Observational and Turbulence Analysis for the Faraji Hurricane

A Satellite Analysis: Comparing Two Medicanes

New investigation of a tropical cyclone: observational and turbulence analysis for the Faraji hurricane

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