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Estevez J.,University of Cordoba, Spain | Gavilan P.,Center Alameda del Obispo | Garcia-Marin A.P.,University of Cordoba, Spain | Zardi D.,University of Trento | Zardi D.,National Consortium of Universities for Atmospheric and Hydrospheric Physics
International Journal of Climatology | Year: 2015

Tipping-bucket rain gauges are convenient and reliable sensors of rainfall measurements; however, like all other field sensors, they are subject to different kinds of errors. Due to their location, rain gauges in this research can record accidental pulses produced by vibrations from works of farm machineries near the station, or may receive water from sprinkler irrigation systems. These spurious inputs are recorded as precipitation data, although they do not correspond to rain, so it is necessary to detect them in order to avoid their inclusion in the future soil-water balance. The main objective of this work is to design a simple quality control procedure to validate precipitation data generated in several stations of the Agroclimatic Information Network of Andalusia (southern Spain), and valid for similar agro-meteorological station networks. The relationship between the degree of cloudiness through attenuation of solar radiation (atmospheric transmittance coefficient), relative humidity and rainfall measurements has been studied in order to separate true and false precipitation records. Meteorological data from 2002 to 2011 were used for the study. © 2014 Royal Meteorological Society. Source


Zardi D.,University of Trento | Zardi D.,National Consortium of Universities for Atmospheric and Hydrospheric Physics | Serafin S.,University of Vienna
Quarterly Journal of the Royal Meteorological Society | Year: 2015

The article examines the flow generated by time-periodic variations in surface temperature along an infinite slope in an initially unperturbed, stably stratified atmosphere at rest. Uniform boundary conditions at the surface are conducive to an along-slope parallel flow, governed by a periodically reversing local imbalance between along-slope advection and slope-normal fluxes of momentum and heat. It is shown that solutions include both a transient part and a periodic regime and that three different flow regimes may occur. The properties of the solutions in each regime are examined and discussed, outlining novelties with respect to previously known results. © 2015 Royal Meteorological Society. Source


Laiti L.,University of Trento | Laiti L.,National Consortium of Universities for Atmospheric and Hydrospheric Physics | Zardi D.,University of Trento | Zardi D.,National Consortium of Universities for Atmospheric and Hydrospheric Physics | And 7 more authors.
Atmospheric Chemistry and Physics | Year: 2014

This study investigates the thermal structures of the atmospheric boundary layer (ABL) and the near-surface wind field associated with a lake-valley circulation in the south-eastern Italian Alps-the so-called Ora del Garda. Two flights of an equipped motorglider allowed for the exploration of the diurnal evolution of this circulation, from the onset, on Lake Garda's shoreline, throughout its development along the Sarca Valley and Lakes Valley (Valle dei Laghi), to the outflow into the Adige Valley. At the same time, surface observations, both from a targeted field campaign and from routinely operated weather stations, supported the analysis of the development of the Ora del Garda at the valley floor. In particular, in the valleys typical ABL vertical structures, characterized by rather shallow convective mixed layers (∼500 m) and (deeper) weakly stable layers above, up to the lateral crest height, are identified in the late morning. In contrast, close to the lake the ABL is stably stratified down to very low heights, as a consequence of the intense advection of colder air associated with the Ora del Garda flow (up to 6ms-1). The combined analysis of surface and airborne observations (remapped over 3-D high-resolution grids) suggests that the lake-breeze front propagating up-valley from the shoreline in the late morning penetrates slightly later at the eastern end of the valley inlet (delay: ∼1 h), probably due to the asymmetric radiative forcing caused by the N-S valley orientation. On the other hand, in the early afternoon the Ora del Garda overflows through an elevated gap, producing an anomalous, strong cross-valley wind (5ms-1) at the Adige Valley floor north of Trento, which overwhelms the local upvalley wind. This feature is associated with a strong deepening of the local mixed layer (from 400 to 1300 m). The potential temperature 3-D field suggests that the intense turbulent mixing may be attributed to the development of a downslope wind across the gap, followed by a hydraulic jump downstream. © 2014 Author(s). Source


Laiti L.,University of Trento | Laiti L.,National Consortium of Universities for Atmospheric and Hydrospheric Physics | Zardi D.,University of Trento | Zardi D.,National Consortium of Universities for Atmospheric and Hydrospheric Physics | And 5 more authors.
Atmospheric Science Letters | Year: 2013

Residual kriging (RK) is applied to data from measurements performed with an instrumented motorglider in an Alpine Valley, where a coupled lake and valley wind develops. Results provide an insight into a typical mean vertical structure of the valley boundary layer, displaying a rather shallow convective mixed layer, surmounted by a deep stable layer. Mapping with RK allows to detect spatial temperature anomalies associated with the local development of diurnal winds over each explored valley cross section. Local scale features, such as cross-valley thermal asymmetries, amenable to surface inhomogeneities and their effects on heat fluxes, are also identified. © 2013 Royal Meteorological Society. Source


Laiti L.,University of Trento | Laiti L.,National Consortium of Universities for Atmospheric and Hydrospheric Physics | Zardi D.,University of Trento | Zardi D.,National Consortium of Universities for Atmospheric and Hydrospheric Physics | And 5 more authors.
Atmospheric Research | Year: 2013

The paper investigates a coupled lake-breeze and valley-wind system, known as Ora del Garda. The latter typically originates on clear-sky days over the northern shore of Lake Garda in the Alps. After channelling into the nearby Sarca Valley and Lakes Valley, this airflow finally breaks out, through an elevated saddle, into the adjacent Adige Valley, where it strongly interacts with the local valley wind. Two flights of an instrumented motorglider explored, under different synoptic conditions, the thermal structure of the atmospheric boundary layer (ABL) associated with this wind at selected vertical sections-namely over the lake shore, at mid-valley, and at the junction with the Adige Valley. Data from airborne measurements, as well as from weather stations disseminated along the valley floor, provided the basis for mapping 3D fields of potential temperature over high-resolution grids by means of a Residual Kriging (RK) technique. This representation allowed the identification of site-specific ABL features associated with the Ora del Garda. In particular, a typical daytime coastal-breeze structure is detected in the lake shore region, where the advection of colder air tends to stabilize the atmosphere throughout the ABL depth. Mid-valley vertical profiles from both flights display shallow convective mixed layers, surmounted by deeper weakly stable layers. On the other hand, RK-gridded temperature maps show cross-valley thermal asymmetries, amenable to the complex topography and to the inhomogeneous surface coverage, as well as to a curvature of the valley axis. Finally, in the area where the upper Lakes Valley joins the Adige Valley, specific features associated with the complex interaction between the Ora del Garda and the local up-valley wind are found. © 2013 Elsevier B.V. Source

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