GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 Temperature variability assessment at vineyard scale: control of data accuracy and data processing protocol

Temperature variability assessment at vineyard scale: control of data accuracy and data processing protocol

Abstract

Context and purpose of the study – Climatic variability studies at fine scale have been developed in recent years with the reduction of material cost and the development of competitive miniaturized sensors. This work is forming part the LIFE-ADVICLIM project, of which one of the objectives is to model spatial temperature variability at vineyard scale. In the Bordeaux pilot site, a large network of data loggers has been set up to record temperature close to the vine canopy. The reduced distance between plant foliage and measurement equipment raises specific issues and leads to an increased rate of outliers compared to data retrieved from classical weather stations. Some of these were detected during data analysis, but others could not be easily identified. The present study aims to address the issue of data quality control and provide recommendations for data processing in climatic studies at fine scale.
Material and methods – Temperature variability at vineyard scale was assessed from a network of 90 temperature stations set up in Saint-Emilion, Pomerol, and their satellite appellations. In order to test the accuracy of the measurement, 2 temperature sensors T1 and T2 (Tinytag talk 2, Gemini UK) have been connected to each temperature station and programmed to record hourly minimum and maximum temperature. The accuracy given by the constructor for this material is 0.4°C. The difference between the 2 sensors for each temperature station was analyzed during the 2017 campaign and compared. A classical meteorological station installed in Saint-Emilion (Meteo France) provided the information on climatic condition in the pilot site. A temperature station was also set up next to this meteorological station to assess both the impact of canopy and the type of material on temperature. Raw temperature data and bioclimatic indices like Winkler index were analyzed.
Results – Differences exceeding material accuracy have been detected over the whole network for several locations and dates. Average of differences is higher for maximum temperature than minimum when the whole year is taken into account. Differences can change Winkler index up to 106 degree.days for the same temperature station. Seasonal effect was observed for minimum and maximum temperature with higher differences between T1 and T2 during the winter.
Significant difference on maximum temperature was observed between data from the classical meteorological station and temperature recorded by the neighboring data logger installed in the canopy. Temperature recorded by temperature station is 1 to 4 °C warmer because the solar shield is less ventilated. A seasonal effect was observed, with higher difference recorded during the summer, which induced significant differences between calculated degree days. To eliminate confusion between degree days recorded by these 2 systems, a “Canopy Winkler Index” was created for the Winkler Index constructed with the temperature station, located inside the canopy.
Careful data processing is needed to obtain accurate temperatures from miniaturized temperature station located inside the canopy. Installation of 2 sensors for each temperature station is recommended to control and detect outliers. An automatic data processing system is under development to detect and replace outliers.

DOI:

Publication date: March 11, 2024

Issue: GiESCO 2019

Type: Poster

Authors

Théo PETITJEAN1*, Laure de RESSEGUIER1, Hervé QUENOL², Cornelis van LEEUWEN1

1 EGFV, Bordeaux Sciences Agro, INRA, Univ. Bordeaux, F-33882 Villenave d’Ornon, 
² LETG-Rennes, CNRS-UMR 6554, Université Rennes-2, Place Recteur H. Le Moal, 35043 Rennes cedex, France

Contact the author

Keywords

Fine scale, Temperature variability, Temperature stations, Data accuracy, Data processing , Vineyards

Tags

GiESCO | GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Variations of soil attributes in vineyards influence their reflectance spectra

Knowledge on the reflectance spectrum of soil is potentially useful since it carries information on soil chemical composition that can be used to the planning of agricultural practices. If compared with analytical methods such as conventional chemical analysis, reflectance measurement provides non-destructive, economic, near real-time data. This paper reports results from reflectance measurements performed by spectroradiometry on soils from two vineyards in south Brazil. The vineyards are close to each other, are on different geological formations, but were subjected to the same management. The objective was to detect spectral differences between the two areas, correlating these differences to variations in their chemical composition, to assess the technique’s potential to predict soil attributes from reflectance data.To that end, soil samples were collected from ten selected vine parcels. Chemical analysis yield data on concentration of twenty-one soil attributes, and spectroradiometry was performed on samples. Chemical differences significant to a 95% confidence level between the two studied areas were found for six soil attributes, and the average reflectance spectra were separated by this same level along most of the observed spectral domain. Correlations between soil reflectance and concentrations of soil attributes were looked for, and for ten soil traits it was possible to define wavelength domains were reflectance and concentrations are correlated to confidence levels from 95% to 99%. Partial Least Squares Regression (PLSR) analyses were performed comparing measured and predicted concentrations, and for fifteen out of 21 soil traits we found Pearson correlation coefficients r > 0.8. These preliminary results, which have to be validated, suggest that variations of concentration in the investigated soil attributes induce differences in reflectance that can be detected by spectroradiometry. Applications of these observations include the assessment of the chemical content of soils by spectroradiometry as a fast, low-cost alternative to chemical analytical methods.

The true cost of the vineyard landscape enhancement. First results in the Venezia biodistrict 

The research is part of the “Ecovinegoals” project, financed by Interreg Adrion funds. It aims to encourage the adoption and dissemination of agroecological practices in intensive wine-growing areas. The study focuses on cost analysis of the wine-growing landscape enhancement in an organic winery in order to provide a useful tool for winemakers to direct their investments in green infrastructures. One of the Italian pilot areas of the Ecovinegoals project is the Venezia Biodistrict, characterized by viticulture in a flat reclamation area of 105,800 hectares.

Estudio de la adaptación y del comportamiento productivo y enológico de variedades blancas foráneas en la zona vitícola del Penedés

Estudio comparativo del comportamiento de ocho variedades de viníferas blancas en el Penedés, injertadas sobre los portainjertos 41-B y 110-R.
Se describen los comportamientos

The impacts of frozen material-other-than-grapes (MOG) on aroma compounds of red wine varieties

An undesirable note called “floral taint” has been observed in red wines by winemakers in the Niagara region caused by large volumes of frozen leaves and petioles [materials-other-than-grapes (MOG)] introduced during mechanical harvest and subsequent winemaking late in the season. The volatiles, which we hypothesized are responsible, are primarily terpenes, norisoprenoids, and specific esters in frozen leaves and petioles. The purpose of this study was to investigate the volatile compounds which may cause the floral taint problem and explore how much of them (thresholds) may lead to the problem. Also, the glycosidic precursors of some of these compounds were analyzed to see the changes happening during frost events.

NMR profiling of grape musts from some italian regions

With wine fraud, being a widespread problem [1], the need for more sophisticated and precise analytical methods of its detection remains ever persistent.