Satellite data analysis
Copernicus
Copernicus is the European Union's Earth observation programme, dedicated to monitoring our planet and its environment.
The programme uses huge amounts of data from satellites and ground, airborne and maritime measurement systems to provide information to help improve the quality of life of European citizens.
The information services are accessible to citizens free of charge. We used EO Browser to derive the images and data shown in this page.
Pollution in our area
Nitrogen dioxide (NO2)
Nitrogen oxides are gases present in the earth's atmosphere, particularly in the troposphere and stratosphere. These gases are the result of anthropogenic activities, combustion of fossil fuels and biomass, but also of natural processes such as fires, lightning, and microbiological processes in the soil.
The Po Valley, and in particular the areas of Monza and Milan, have been in the news in the early months of 2024 due to high levels of air pollution.
The seriousness of the situation is easily visible through satellite data. It is clear that the Po Valley is one of the most polluted regions in Europe.
The most polluted areas are marked in red, with a high presence of nitrogen oxides.
The least polluted areas are coloured in blue, with the presence of nitrogen oxides close to zero.
The effects of the bad weather on 25 July 2023
Through Sentinel satellite images we tried to study and observe the effects of the bad weather of 25 July 2023 on the vegetation of our city. In particular, we focused on Monza Park on two dates: 20 July 2023 and 14 August 2023.
The following images were taken with the Barren soil filter, which allows to map the soil and its fertility. All regions with vegetation are shown in green, while barren soil appears in red. This filter is useful to investigate the extent of phenomena such as erosion and desertification.
A comparison of the two images immediately shows the destructive effects of the bad weather of 25 July: in the entire northernmost area of the park, between Biassono and Lesmo, there is a severe lack of vegetation. A closer look reveals that the damage also extends to other regions of the park, such as the area around the racing track facilities.
The following images represent the NDVI, normalised difference vegetation index. This is a simple but effective index for quantifying green vegetation. It measures the health of vegetation based on how plants reflect light at specific wavelengths. The value of NDVI varies between -1 and 1. Negative values near -1 correspond to water. Values near zero (-0.1 to 0.1) usually correspond to dry areas of rock, sand or snow. Small positive values correspond to meadows and shrubs (0.2 to 0.4), high values close to 1 indicate lush forests.
Again, a comparison of the two images shows the disappearance of large areas of healthy vegetation between 20 July and 14 August 2023, as is also evident from photographs taken a few months later (on the right below).
The graphs below show a histogram of the NDVI values over the entire park area. Not only there is a clear decrease in the maximum intensity, but also a widening of the graph, clearly indicating a worse state of health of the vegetation.
Vegetation health analysis from 2017 to 2023
We then observed with Sentinel satellite images how the health of our city's vegetation has changed between 2017 and 2023. We created timelapses for the months of January, April, July and October, with an image for each year. This allowed us to compare data and changes in vegetation health between seasons and years.
The folloqing images represent the NDVI, normalized difference vegetation index.
The following images represent the Normalised Difference Moisture Index (NDMI), which is used to determine the water content of vegetation and to monitor drought. The NDMI value varies between -1 and 1. Negative values approaching -1 correspond to barren soil. Values close to zero (between -0.2 and 0.4) usually correspond to water stress. High values correspond to lush vegetation without water stress (between 0.4 and 1).
From the previous timelapses, the seasonal variations of vegetation humidity can be clearly observed.
It can be seen that 2022 was an extremely dry year, especially in the summer and spring months.