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The interplay between grape ripening and weather anomalies in Northern Italy – A modelling exercise
Get PDFCurrent climate change is increasing inter- and intra-annual variability in atmospheric conditions leading to grapevine phenological shifts as well as altered grape ripening and composition at ripeness. This study aims to i) detect weather anomalies within a long-term time series, ii) model grape ripening revealing altered traits in time to target specific ripeness thresholds for four Vitis vinifera cultivars, and iii) establish empirical relationships between ripening and weather anomalies with forecasting purposes. The Day of the Year (DOY) to reach specific
grape ripeness targets was determined from time series of sugar concentrations, total acidity and pH collected from a private company in the period 2009–2021 in North-Eastern Italy. Nonlinear regression models were fitted over a time series of ripening parameters on a calendar time basis and assessed for modelling efficiency (EF) and error of prediction (RMSE) in four grapevine cultivars (Merlot, Cabernet-Sauvignon, Glera and Garganega). For each vintage and cultivar, advances or delays in DOY to target specified ripeness thresholds were assessed with respect to the average ripening dynamics. A thirteen years’ long meteorological series monitored at a ground weather station using hourly air temperature and rainfall data was analysed. Climate statistics were obtained and for each time interval (month, bimester) weather anomalies were identified. A linear regression analysis was performed to assess correlations between ripening and weather anomalies. For each cultivar, ripeness advances or delays expressed in the number of days to target the specific ripening threshold were assessed in relation to registered weather anomalies and the specific reference time interval in the vintage. Precipitation of the warmest month and temperature anomalies during late spring (May–June) and during the warmest month (August) we found to be important to understanding the effect of climate change on sugar ripeness. Maximum and minimum temperatures of the May–June bimester and maximum temperatures of the warmest month best correlate with altered total acidity evolution and pH increment during the ripening process. A new modelling framework is presented using historical data that supports management decisions by better understanding past impacts and forecasting for the future
Bilanci di energia, acqua e carbonio del vigneto: un approccio multi - scala
Get PDFThe research, carried out in 2006 and 2007, concerned the dynamics of the key physiological processes in a vineyard of the Venetian Region. The study allowed a detailed characterization of the energy, hydrological and carbon budget of the vineyard.
The measurements have been conducted at different spatial and temporal scales from the leaf, to the canopy, and up to whole the vineyard.The measurements at leaf scale permitted the parameterization of the Farquhar model of photosynthesis to interpret the physiological response of the leaf to the different environment variables. The continuous monitoring of energy and mass fluxes performed during the two years using the eddy covariance micrometeorological technique, has been used to assess the energy balance, the actual evapotranspiration, and the Net Ecosystem Exchange of the vineyard at the plot scale. A further up-scaling has been carried out using remote sensing techniques, in order to study the possibility of regionalization of the physiological processes measured at lower scales. Detailed biometrical measurements were collected during the same growing seasons, to compare the trend of the growths and carbon allocation in the different parts of the vineyard and validate the overall budget.
The adopted multi-scale approach allowed to collect unique dataset, useful to get a clear picture of the energy balance, mass exchange, and growth processes of the vineyard, and a good agreement between the different scales explored was achieved. The carbon budget, assessed and cross-validated at different scales, underlines the role of the vineyard as a possible sink of CO2, in contrast with most of the agricultural crops. A positive sink activity of the vineyard, even taking into account the harvested dry matter, can add a further environmental value to Viticulture
Comparison of MODIS-based evapotranspiration estimates with eddy covariance measurements on a vineyard in North-Eastern Italy
No full textStima dei flussi di evapotraspirazione e fotosintesi del vigneto mediante tecniche micrometeorologiche
No full textUse of hyperspectral data for assessing vineyard biophysical and quality parameters in Northern Italy
No full textA total of 39 study sites from 11 commercial vineyards located in two traditional growing areas of Northern Italy were identified for airborne hyperspectral acquisition in summer 2009 with the Aisa-EAGLE Airborne Hyperspectral Imaging Sensor.
Field sampling campaigns were conducted during the airborne overflights and around harvest, collectin canopy srtructural parameters, leaf and canopy biophysical characteristics as well as spectral signatures and must quality traits.
Several vegetation indices were calculated from each plot to relate variations in canopy structure and foliar pigment concentration to vine status and grape quality parameters.
The up-scaling model through TCARI/OSAVI index allowed to yield acceptable estimates of leaf chlorophyll content. However model refinements are needed to improve its capacity to taking into account understory grass cover at the highest intrument resolution
Using MODIS data for monitoring evapotranspiration in vineyards
No full textIn North-Eastern Italy water demand for vineyards irrigation is constantly increasing, but this conflicts with the high civil and industrial rates of water consumption in the region, which is one of the most densely populated in Europe. An appropriate management of water resources is therefore mandatory to maximise the efficiency of the whole water supply system. In this context, the fundamental prerequisite is the accurate assessment of the amount and spatio-temporal distribution of vineyard evapotranspiration (ET). This work aims at developing methodologies based on Remote Sensing for mapping water consumption in vineyards at the regional level. MODIS data, which are released at a very high time frequency with a high spectral resolution, appear to be suitable to derive usefuil information about the physiological status of vegetation, including ET. A study-site, consisting in a rather extended vineyard (25 ha) was individuated, and a monitoring eddy flux tower was installed. After having obtained MODIS time-series data for the site, ET was estimated according to a modelling approach based on MODIS data coupled with ground-measured daily meteorological observations. ET estimates were then validated against a four-years dataset of eddy covariance measurements. Two-years time-series of measurements were used for calibrating the models, while the other two were reserved for independent validation. The results obtained showed good consistency with in situ observations, and demonstrate that MODIS data are potentially suitable for monitoring ET in vineyards at the regional scale
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