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Comparison of MODIS-based evapotranspiration estimates with eddy covariance measurements on a vineyard in North-Eastern Italy
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Trends in phenology of grapevine in North-Eastern Italy.
No full textPlants are sensitive indicators of climate change and the analysis of shifts in phenological records may help in
confirming trends not easily detected by instrumental observations alone.
We have analyzed a detailed phenological database for grapevine, using observations collected from 1986 to 2008
in two sites of North-Eastern Italy, on the cultivars Prosecco, Chardonnay, Merlot and Cabernet Sauvignon. Parameters
of models for winter dormancy, vegetative growth, and ripening phases have been fitted and validated on
a subset, yielding a consistent estimate of chilling and heat requirements.
A significant shift of flowering, veraison and harvest dates were observed, reaching almost -1 day per year in
the warmer site for the earlier cultivars. While traditional breeding programs have been so far seeking for early
ripening capacity, the trends we detected show the close risk of a negative impact of climate change on enological
characteristics of grapes even in Northern Italy and the opportunity to look for late-ripening types
Testing MODIS products against eddy fluxes and biometric features in a vineyard in North-Eastern Italy
No full textIn a typical wine growing area of the Veneto Region (North Eastern Italy, 45° 74' N, 12° 44' E), a monitoring station has been set up on a vineyard and operated since summer
2005. Being flat, homogeneous and extensive (25 hectares), the plot is very well suited both for direct micrometeorological measurements and remote sensing observations.
The site was intended to be an anchor station to study grapevine energy, water and carbon budgets in quasi-ideal conditions. The vineyard is also characterized by a very uniform management (cultivar, pruning, plant height) and soil profile.
Belonging to the CarboItaly/FLUXNET network, an eddy covariance tower provides continuous measurements of sensible heat, water vapour and carbon dioxide fluxes
since date of deploying, and benefits of specially-processed products by the Moderate Resolution Imaging Spectroradiometer (MODIS) initiative. At the coarsest resolution (1 km), more than 80% of the pixel centred on the tower contains the vineyard canopy, while for the middle and highest resolutions (500 and 250 m) 100% vineyard pixels
are available. Vegetative growth (leaf area, above-ground biomass), canopy parameters (leaf gas exchange, plant water status, radiation interception), phenological development, fruit growth and final yield are also monitored.
MODIS products related to vegetation properties (e.g. LAI, FPAR, NDVI) were tested against ground-based biometric measurements as predictors for grapevine canopy features.
While the validation activity is still under completion due to temporary unavailability of part of MODIS data, still undergoing a reprocessing, results obtained so far were generally in a good agreement with the in situ observations
Use 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
ICARO: un software per valutare l’idoneità dei terreni agrari alla distribuzione delle acque reflue dei frantoi oleari
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Validation of phenological models for grapevine in the Veneto Region
No full textIn this study we have compared the predictive ability of two phenological models: a traditional Thermal Time (TT) and a version of the more recently developed Unified Model (UM). Unlike TT, which quantifies the accumulation of heat units which trigger bud break and the subsequent development phases, the UM describes also the fulfillment of chilling requirements, predictiing the date of dormancy break, and implements a finer description of the plant development temperature-dependancy. The model were fitted and validated on phenological observations collected from 1986 to 2008 in a site of North-Eastern Italy, on the cultivars Glera, Chardonnay, Merlot and Cabernet Sauvignon.
The UM fitted better to observations than TT, and yielded more accurate estimates on the validation dataset. In both models, the accuracy of estimates decreasedf from bud break to veraison
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