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1.
G. Mastrantonio A. P. Viola S. Argentini G. Fiocco L. Giannini L. Rossini G. Abbate R. Ocone M. Casonato 《Boundary-Layer Meteorology》1994,71(1-2):67-80
In the period June–July 1992, four Doppler sodars were operated simultaneously in Rome and the surrounding area. The data have been used to investigate the contributions from sea breeze events to the local low-level circulation. Three days in which synoptic-scale pressure gradients were weak have been selected. A number of characteristics of the sea breeze are examined including the onset and cessation of the phenomenon, the behavior of the wind speed, and the depth of the density flow. The time propagation of the events and the influence of orography are obtained from a comparison between the data at different sites. The low-level circulation in the early morning is associated with the land breeze and appears to be enhanced by a mountain wind from the surrounding hills. The observed behavior of the vertical velocity field associated with the sea breeze is consistent with model predictions. 相似文献
2.
A three-axis Doppler system has been set-up in a configuration that allows for simultaneous monostatic and bistatic modes of operation. Each of the antennas radiates a different frequency, and each is allowed to receive and process signals at three frequencies. A considerable increase in the information retrieved appears to be possible: preliminary experimental results are presented. 相似文献
3.
P. Martano D. Cava G. Mastrantonio S. Argentini A. Viola 《Boundary-Layer Meteorology》2005,115(1):85-103
Nocturnal convection, originating in a well-mixed marine cloud-topped boundary layer, advected onshore, was observed using a Doppler sodar on the Tyrrhenian coast in Italy. The horizontal and vertical dimensions of the downdrafts were evaluated. The oscillation frequency triggered by the downdrafts at the inversion layer, derived from the harmonic analysis of the sodar measured vertical velocity (w), is compared with the Brunt-Vaisala frequency, obtained from the rawinsonde temperature profile. A similarity function for the 2w vertical profile was used to fit the sodar experimental data and to retrieve the depth of the mixing layer and the sensible heat flux at the top of the cloud layer. The results are in agreement with the convection layer depth observed in the sodar echoes facsimile record, and with the energy budget evaluated at the top of the cloud layer using the rawinsonde profiles. 相似文献
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Igor Petenko Giangiuseppe Mastrantonio Angelo Viola Stefania Argentini Ilaria Pietroni 《Boundary-Layer Meteorology》2014,150(2):215-233
The characteristics of the temporal and height variations of the temperature structure parameter $C_\mathrm{T}^{2}$ in strongly convective situations derived from the sodar echo-signal intensity measurements were analyzed for the first 100 m. It was corroborated that the probability density function (pdf) of the logarithm of $C_\mathrm{T}^{2}$ in the lower convective boundary layer is markedly non-Gaussian, whereas turbulence theory predicts it to be normal. It was also corroborated that the sum of two weighted Gaussians, which characterize the statistics of $C_\mathrm{T}^{2}$ within convective plumes and in their environment and the probability of plume occurrence, well approximates the observed pdfs. It was shown that the height behaviour of the arithmetic mean of $ C_\mathrm{T}^{2}$ (both total and within plumes) follows well a power law $C_\mathrm{T}^{2} (z) \sim z^{-q}$ with the exponent $q$ close to the theoretically predicted value of 4/3. But for the geometrical means of $C_\mathrm{T}^{2}$ (both total and within the plumes), $q$ is close to 1. The difference between arithmetically and geometrically averaged $C_\mathrm{T}^{2}$ profiles was analyzed. The vertical profiles of the standard deviation, skewness and kurtosis of $\hbox {ln}C_\mathrm{T}^{2}$ pdfs were analyzed to show their steady behaviour with height. The standard deviations of the logarithm of $C_\mathrm{T}^{2}$ within the plumes and between them are similar and are 1.5 times less than the total standard deviation. The estimate of the variability index $F_\mathrm{T}$ and its height behaviour were obtained, which can be useful to validate some theoretical and modelling predictions. The vertical profiles of the skewness and kurtosis show the negative asymmetry of pdfs and their flatness, respectively. The spectra of variations in $\hbox {ln}C_\mathrm{T}^{2}$ are shown to be satisfactorily fitted by the power law $f^{-\gamma } $ in the frequency range 0.02 and 0.2 Hz, with the average exponent $\approx $ 1.27 $\pm $ 0.22. 相似文献
6.
Local Circulation Diurnal Patterns and Their Relationship with Large-Scale Flows in a Coastal Area of the Tyrrhenian Sea 总被引：1，自引：0，他引：1
Igor Petenko Giangiuseppe Mastrantonio Angelo Viola Stefania Argentini Lucia Coniglio Paolo Monti Giovanni Leuzzi 《Boundary-Layer Meteorology》2011,139(2):353-366
In order to characterise the local low-level circulation in the Tyrrhenian Sea coastal area near Rome, the wind field observed
by conventional anemometers, Doppler sodar, and rawinsonde has been analysed. The prevailing diurnal behaviour of wind speed
and direction as a function of season was highlighted, and the existence of two different patterns of the local circulation,
mainly due to land and sea breezes and to the drainage flow from the mouth of the Tiber valley, revealed. The comparison between
the low-level circulation and synoptic flow allowed us to determine the influence of the large-scale flow on nocturnal currents
that are observed at the Pratica di Mare site and the way that wind direction evolves during the day. Numerical simulations
are consistent with experimental data and depict the main features of the low-level wind field in the area. 相似文献
7.
Antonello Maruotti Antonio Punzo Gianluca Mastrantonio Francesco Lagona 《Stochastic Environmental Research and Risk Assessment (SERRA)》2016,30(6):1725-1740
The modelling of animal movement is an important ecological and environmental issue. It is well-known that animals change their movement patterns over time, according to observable and unobservable factors. To trace the dynamics of behaviors, to identify factors influencing these dynamics and unobserved characteristics driving intra-subjects correlations, we introduce a time-dependent mixed effects projected normal regression model. A set of animal-specific parameters following a hidden Markov chain is introduced to deal with unobserved heterogeneity. For the maximum likelihood estimation of the model parameters, we outline an expectation–maximization algorithm. A large-scale simulation study provides evidence on model behavior. The data analysis approach based on the proposed model is finally illustrated by an application to a dataset, which derives from a population of Talitrus saltator from the beach of Castiglione della Pescaia (Italy). 相似文献
8.
This paper focuses on the historical range of variability of landslide activity and its relation to climate in the Aconcagua Park, Argentina. Landslide frequency data are obtained through historic compilation, including the review of more than 85 data sources and personal interviews with members of the local community. Based on these records, the study analyzes major landslide triggering mechanisms and evaluates the role of climate. Slope instability in Aconcagua Park appears to be mainly forced by the melting of snow accumulated during the winter season, which in turn promotes soil saturation and landslide occurrence the following spring–summer (December–February). This finding is supported by a strong correlation between landslides and stream flows of Andean rivers. These peaks occur during warmer seasons, fed by snow and ice‐glacier melting. In contrast, the correlation between landslide frequency and precipitation (diary/accumulative/monthly/annual) is less certain; and the relationship of landslide to temperature records (mean annual temperature/mean temperature during November–February period) is weak. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
9.
G. Mastrantonio V. Malvestuto S. Argentini T. Georgiadis A. Viola 《Meteorology and Atmospheric Physics》1999,71(1-2):127-132
Summary The development of a convective boundary layer over the Antarctic Plateau is documented by a Doppler minisodar data-set recorded
during a 10 day campaign in January 1997. The vertical velocities associated with thermals do not exceed 1 m/s, while the
depth of the convective layer, usually less than 200 m, never surpasses 300 m. Measurements of momentum flux, sensible heat
flux, wind speed and radiation budget show characteristics that are typical of a convective boundary layer evolution. The
diurnal behaviour of absolute humidity, however, exhibits features that are not expected, e.g. anticorrelation with incoming
net radiation and air temperature.
Received October 30, 1998 Revised May 26, 1999 相似文献
10.
Igor Petenko Giangiuseppe Mastrantonio Angelo Viola Stefania Argentini Ilaria Pietroni 《Boundary-Layer Meteorology》2012,143(1):125-141
Some characteristics of wavelike motions in the atmospheric boundary layer observed by sodar are considered. In an experiment
carried out in February 1993 in Milan, Italy, Doppler sodar measurements were accompanied by in situ measurements of temperature
and wind velocity vertical profiles using a tethered balloon up to 600 m. The oscillations of elevated wavy layers containing
intense thermal turbulence, usually associated with temperature-inversion zones, were studied by using correlation and spectral
analysis methods. The statistics of the occurrence of wavelike and temperature-inversion events are presented. The height
distributions of Brunt–Vaisala frequency and wind shear and their correlation within elevated inversion layers were determined,
with a strong correlation observed between the drift rate of the wavy layers and the vertical velocity measured by Doppler
sodar inside these layers. Spectral analysis showed similarities regarding their frequency characteristics. The phase speed
and propagation direction of waves were estimated from the time delay of the signals at three antennae to provide estimates
of wavelength. Moreover, wavelengths were estimated from the intrinsic frequency obtained from sodar measurements of the Doppler
vertical velocity and oscillations of wavy turbulent layers. The two wavelength estimates are in good agreement. 相似文献