The map shows the Saturnalia Vigour Index (SVI) computed over the Margaux appellation.
The greener is the colour, the higher the estimated vine vigour. Lower wines vigour has been found to be directly linked to wine quality ( Filippetti I., 2013 , Dry P.R., 1998 ), particularly when is combined with other variables analysis, such as in Saturnalia's case.
The pie chart shows that 83% of the values are between the medium and high SVI.
SVI distribution across vintages give us an idea of the relative quality that is to be expected in each one of them. 2018, considered a high quality vintage, shows lower vigour, with 32% of the vineyards classified as medium, which also suggests higher ripeness and alcohol content. 2019 seems to be more classic in this respect, and more similar to 2016 in quality and style.
This graph describes the distribution of SVI within the appellation, showing high homogeneity (normal distribution shape with rather narrow peak) within the vintages, which in itself is an indication of the high quality of the terroir. Again, 2018 shows a more compacted distribution towards the lower level of vigour, typical of this very ripe and dry vintage, whereas 2019 seems to be aligned with more classic 2016 and 2015 to a certain extent.
Rainfall distribution throughout the year (top-left) shows that 2019 was one of the driest summer seasons, even drier than 2018, whereas spring rain was similar to 2016 and 2018, suggesting a lighter year in terms of pathogens pressure in the vineyard. The total amount of rain from November to October (top-right) was similar to 2015.
The total of Growing Degree Days (GDD, top-right) describes the amount of heat available for the plant growth, showing that 2019 wasn't extreme in this sense, more similar to 2017 than warmer 2018 and above all 2015, and cooler 2016. The distribution of GDD (bottom-left) shows that initial growth in 2019 was similar to 2017, followed by a slow-down in spring.
Diurnal variation (bottom-right) is important to describe the difference in temperature between night and day, which is often considered important for the development of aromas and phenolic maturity. In this respect, 2019 shows a lower difference (i.e. smaller difference between night and day temperature), particularly after veraison and through the harvest.