Application of the Hess-Brezowsky classification to the identification of weather patterns causing heavy winter rainfall in Brittany (France)

An accurate knowledge of the weather patterns causing winter rainfall over the Scorff watershed in western Brittany (W. France) was developed prior to studies of the impact of the climate factor on land use management, and of the hydrological reponses to rain-producing weather patterns. These two studies are carried out in the context of the climate change. The identification of rainy air-circulation types was realized using the objective computational version of the 29-type Hess and Brezowsky Grosswetterlagen system of classifying European synoptic regimes, for the cold season (November-March) of the 1958–2005 period at the reference weather station of Lorient, and 13 other stations located in western and southern Brittany, including a more detailed study for the wet 2000–2001 cold season for three reference stations of the Scorff watershed (Lorient, Plouay and Plouray). The precipitation proportion (including the days with rainfall ≥20 mm) was calculated by major air-circulation type (GWT: see Appendix A) and by individual air-circulation subtype (GWL: see Appendix A) for the studied time-period. The most frequently occurrence of rainy days associated with westerly and southerly GWL confirmed well-known observations in western Europe and so justify the use of the Hess-Brezowsky classification in other areas outside Central Europe. The southern or south-western exposure of the watershed with a hilly inland area enhanced the heavy rainfall generated by the SW and S circulation types, and increased the difference between the rainfall amounts of coastal and inland stations during the wettest days

La vid (Vitis vinífera L. cv. Tannat) como indicadora del cambio climático: el caso de Uruguay

Es conocido el hecho que las plantas responden a las condiciones climáticas del año. La vid es particularmente sensible a las temperaturas diurnas y nocturnas así como al régimen hídrico que se expresa en la respuesta de la planta: variación en la duración de los estados fenológicos como la maduración, composición de la uva o en su sanidad. El objetivo de este estudio es mostrar a través de la evolución de índices bioclimáticos adaptados a la vid la variabilidad climática y para los últimos quince años, analizar la respuesta del cultivo al clima, de manera de poder considerar a la vid como posible indicadora del cambio y la variabilidad climática. Para confirmar esta hipótesis se presentan resultados provenientes de una serie de quince años de parcelas de experimentación de la variedad Tannat de viñedos implantados en el sur del Uruguay en el que se relacionan los factores del clima con la respuesta de la planta.Eje: Clima.Universidad Nacional de La Plat

La vid (Vitis vinífera L. cv. Tannat) como indicadora del cambio climático: el caso de Uruguay

Es conocido el hecho que las plantas responden a las condiciones climáticas del año. La vid es particularmente sensible a las temperaturas diurnas y nocturnas así como al régimen hídrico que se expresa en la respuesta de la planta: variación en la duración de los estados fenológicos como la maduración, composición de la uva o en su sanidad. El objetivo de este estudio es mostrar a través de la evolución de índices bioclimáticos adaptados a la vid la variabilidad climática y para los últimos quince años, analizar la respuesta del cultivo al clima, de manera de poder considerar a la vid como posible indicadora del cambio y la variabilidad climática. Para confirmar esta hipótesis se presentan resultados provenientes de una serie de quince años de parcelas de experimentación de la variedad Tannat de viñedos implantados en el sur del Uruguay en el que se relacionan los factores del clima con la respuesta de la planta.Eje: Clima.Universidad Nacional de La Plat

Variability in flowering, fruit set and yield in response to vineyard topography and pruning type in Pinot noir

Aim: This study investigates the effects of site aspect and pruning management on flowering, fruit set and yield in Pinot noir vines. Methods: Two rows of 19-year-old Pinot noir vines were selected within a commercial vineyard with south, hilltop, and north-facing aspects. Vines were either cane- or spur-pruned, retaining 20 nodes per vine. One monitoring vine was selected at each sub-plot (consisting of four vines) and used to assess days to 50% flowering, fruit set (%) and days to 50% veraison. Total soluble solids samples were taken from each sub-plot and vines were harvested separately for yield. Results/Findings: Days to 50% flowering was affected by the topographical position. Vines from south-facing plots reached 50% flowering three days earlier during 2018-19 and eight days earlier 2020-21 compared to other plots. Cane pruning advanced the flowering date by one day compared with spur pruned vines (2019-20). Fruit set (%) was affected by topography. Vines from the hilltop plots had less than 50% fruit set during 2018-19 and 2020-21 compared to south and north plots (>70% fruit set). The lower fruit set was reflected in reduced yields. Despite the delayed flowering, vines from the hilltop position reached 50% veraison four days earlier than vines from the south and north plots during 2020–21. While there were initial differences in total soluble solids (at 7 to 8 oBrix) at six topographical positions, these variations disappeared by the time the vines were ready for a commercial harvest (>20 oBrix). The type of pruning generally had little effect on fruit set, the date of véraison or soluble solids at harvest, although cane pruning resulted in a 40% increase in yield in 2019–20 when compared to spur pruning. Conclusions: Flowering, fruit set, veraison, and vine yield were affected by topography (site aspect) and pruning type had little to no effect. Vine yield was a reflection of the fruit set (%) with differences between topographical positions. Positions with delayed veraison showed delayed soluble solids accumulation but reached a similar harvest soluble solids and yield

La vid (Vitis vinífera L. cv. Tannat) como indicadora del cambio climático: el caso de Uruguay

Es conocido el hecho que las plantas responden a las condiciones climáticas del año. La vid es particularmente sensible a las temperaturas diurnas y nocturnas así como al régimen hídrico que se expresa en la respuesta de la planta: variación en la duración de los estados fenológicos como la maduración, composición de la uva o en su sanidad. El objetivo de este estudio es mostrar a través de la evolución de índices bioclimáticos adaptados a la vid la variabilidad climática y para los últimos quince años, analizar la respuesta del cultivo al clima, de manera de poder considerar a la vid como posible indicadora del cambio y la variabilidad climática. Para confirmar esta hipótesis se presentan resultados provenientes de una serie de quince años de parcelas de experimentación de la variedad Tannat de viñedos implantados en el sur del Uruguay en el que se relacionan los factores del clima con la respuesta de la planta.Eje: Clima.Universidad Nacional de La Plat

Investigation of grapevine areas under climatic stress using high resolution atmospheric modelling: case studies in South Africa and New Zealand

High-resolution atmospheric simulations (500 m) were used to assess viticultural areas under climatic stress in South Africa and New Zealand. The potential areas in which high daytime temperature stress was likely to affect grapevine photosynthesis and grape composition were identified. Results indicated different diurnal temperature variations within the two areas due to synoptic and local environmental factors, often associated with the influence of terrain

The influence of site aspect and pruning types on Pinot noir phenology and shoot growth

Aim: Managing the influence that terroir in vineyards has on vine development depends on improving our understanding the effect of the interaction of within-site variability, within-vine variability, and management practices (such as pruning types) on phenology and vine development. This study evaluates the consequence of site aspect and pruning management on budburst, leaf appearance rate, and shoot growth in Pinot noir vines. Methods and results: Two rows of 19-year-old Pinot noir vines were selected within a commercial vineyard with south, hilltop, and north-facing aspects (note: the north-facing slope is sun-facing in the Southern Hemisphere). Vines were either cane- or spur-pruned, retaining 20 nodes per vine. Budburst, shoot development, and leaf appearance were assessed, and vine trunk circumference was measured to quantify the accumulated differences in vine vigour. Hilltop plots had smaller trunk circumferences when compared to the south- and north-facing plots. Irrespective of topographical positions, budburst was earlier in cane-pruned vines compared to spur-pruned vines, but no differences were observed by the time of 12-leaf stage. The rate of shoot growth reflected the variations in topographical positions and trunk circumference. Cane-pruning exhibited more significant within-vine variation in budburst, budburst duration, and shoot growth when compared with spur-pruning. Shoots from hilltop vines were shorter relative to the vines at other plots for both pruning systems. Conclusions: The rate of shoot growth and development was associated more with site and vine vigour as determined by trunk circumference than pruning type. Spur-pruned vines had a later but more uniform budburst when compared to cane-pruned vines. Significance and impact of the study: Pruning type and within-site variability may lead to differences in canopy density and vine vigour, which can ultimately impact subsequent growth and development of the grapevine. Determining the influence of terroir within the vineyard on budburst, leaf appearance, and shoot growth variability will enable the development of improved phenology and growth models to describe within vineyard variability

Analyse climatique à l'échelle des Coteaux du Layon

International audienceClimate impact studies on vine require downscaling because climatic factors depend on topography, vegetation, orientation …In the framework of the ANR-JC Terviclim, 22 data loggers were settled in the “Coteaux du Layon” vineyards to characterize the particular climate of these terroirs. Temperatures analysis shows strong disparities between data loggers locate on the same plots or on nearby plots. Bioclimatic index as growing degree days are also contrasting depending on the data loggers situation in the vineyardLes études d’impact du climat sur la vigne nécessite de descendre à des échelles très fines car les facteurs climatiques sont tributaires de la topographie, la végétation, les expositions… Dans le cadre du programme ANR-JC Terviclim, 22 capteurs ont été installés dans les vignobles des Coteaux du Layon afin de caractériser le climat particulier de ces terroirs. L’analyse des températures montre de fortes disparités entre les data loggers et pourtant situés parfois sur les mêmes parcelles ou sur des parcelles voisines. Les indices bioclimatiques tels les degrés jours sont également contrastés suivant la situation des capteurs sur les coteau